and so welcome everyone to our university of birmingham and university of birmingham dubai
world water day 2022 event we are absolutely thrilled to have um you with us today and we
are doing it as a split site event and the first part from our dubai campus
and the second part then from our birmingham campus
and we've got an exciting program of speakers and panel discussions lined up and for you today so
and the first part has we have two speakers so we have professor stefan krause and dr chris
bradley both from the university of birmingham and then this afternoon we will have uh four speakers
and who i will introduce to you in the afternoon session um so we also have um yeah
our chair our unesco chair of water who is at today at expo 2020 in dubai so um we'll
be giving some uh shout out to his activities today as well and um give you the hashtag to
follow and things to see what he's up to um so welcome everyone and with no further ado then i
shall introduce our first speaker of this morning so uh professor stefan krause is a professor of
ecohydrology and biogeochemistry at the school of job of the earth and environmental sciences
stefan's interdisciplinary research group work on coupled groundwater and surface water systems
investigating the multifaceted impacts of global environmental change on hydrological fluxes
biogeochemical cycling and contaminant transport he also looks at ecohydrological
feedback functions in complex landscapes stefan is currently pioneering research into the hot spots
and hot moments of microplastic transport and accumulation in fresh water systems and today as
part of our split site uob world water day 2022 event stefan will tell us about his research on
making the invisible visible the global threat of microplastic water pollution over to you stefan
thank you very much sea salt and happy world war today uh a good morning good afternoon depending
on where you are to everyone uh happy about water day from our great uh campus out in in dubai here
and uh the theme for this year's world war today is groundwater making the invisible visible and
that's what we're trying to do here i'm going to talk about the global threat of microplastic
water pollution and many of you might ask oh i can't advance the slides here currently
oh it seems to work this way thank you uh many of you might ask what is invisible in this topic
isn't it something that is in fact very visible isn't it something that's on everybody's mind that
gets a lot of media attention due to the fantastic work of some real advocates of this topic like
sir david attenborough and and his blue planet programs a lot of other people that worked a lot
on raising the awareness for in particular plastic pollution in the oceans and indeed it is and it's
a topic that a lot of people have been working on everyone has some knowledge and many people very
strong opinions on and what i want to focus on today is that more invisible part of that global
plastic cycle if you think about plastic pollution and these are some really uh dramatic data that
we have these are focusing back on on data from 2010 where we had around eight billion
uh uh metric tons of of plastic produced so the numbers that you see are are in thousands
uh metric tons so that's that's the amount of plastic that is being produced and a lot
plastic that gets produced of course ends up in some smaller parts of that in recycling
and they keep in that recycling loop uh some of them are still in stock roughly a quarter
uh and and roughly half of it is getting uh uh used uh uh as it's getting used and gets
to the towards the end of life when it gets uh discarded or some of it actually gets incinerated
but what you see is it's a huge number of of uh plastic waste and the problem arises when that
plastic waste becomes mismanaged when basically it doesn't end up being incinerated or or being
contained but when it ends up in the environment so we know from some key seminal work of of people
like like jenna jambek that a lot of plastic waste actually gets discharged to the oceans by rivers
uh these are model estimates between five and a bit more than 10 million metric tons per year
uh and we know from from some observational work as well that tried to upscale that
uh some of them particularly the largest rivers worldwide initially people thought maybe the top
10 uh most uh polluting rivers contributed a lot and that has been revised recently
to 20 or potentially rather 100 a reverse set that contributed an overly proportional amount
of that plastic waste that that we see visually quite floating on top of the oceans however
if we are quantifying and some people made some fantastic efforts in that in the last five to
ten years how much plastic we we actually see floating in the ocean that is actually orders
of magnitude rather to the tenth to a hundred thousands metric tons uh that that are found
there that's that's in contrast to the uh uh more than a billion rather than the low number
of billion metric tons that have been uh sorry million metric tons that have been uh discharged
uh into the environment already so there seems to be a gap there seems to be a part
of of this plastic cycle that it's more invisible and that's something that in the next 10 minutes
or so i would like to take you on a journey to elucidate a little bit uh so to get a bit of an
insight there and to bust some some plastic myths as we call them with their and the first myth that
we want to to pass there is that the majority of plastic waste is actually accumulated in the
world's ocean i want to show you while there is a lot of plastic waste uh causing dramatic
impact in the world's oceans unfortunately the world oceans are not the only things
but also rivers and the river catchments are heavily affected by by microplastics and larger
parts of plastic as well and they're not merely conduits for plastic transport but also areas
where plastic accumulate for a long time there's a residence time in that in that catchment it's long
enough and then rivers is long enough to actually cause some potentially a quite severe impact so i
want to take you along that journey and start with some fantastic work that one of our undergraduate
students actually did it was a student of one of my colleagues greg sunbrook smith a couple of
years ago who started on our doorstep to look into how much plastics do i find in a river one of our
famous uh famously uh supposedly one of the most polluted rivers in the whole of britain river tame
that flows through birmingham and and he looked into as you can see on that map here
uh quite a lot of uh locations along the river they sampled from microplastics
in the water column and a lot of work up to that point has been trying to identify sources
of microplastic following the hypothesis that you can link microplastic pollution in
watercourses like rivers predominantly through to their main sources which are
uh really pronounced in urban areas what he found was a release very weak relationship to
to that urban areas he found some real hot spots of microplastic pollution and esau said we work a
lot on hot spots as well as hot moments but i also found some areas the microplastic pollution was
significantly lower and very interestingly he found uh that was the main finding of
this otherwise quite complex study was that in particular where we had lakes and reservoirs yeah
not surprisingly the plastic content the microplastic content dropped significantly
and that made us think what what are the reasons for that it's mainly that plastic is a sediment
gets transported a bit differently than other sediments but not that differently
and if your flow velocity goes down it starts to actually fall out and to settle as well
that's one of the processes i mentioned some others in in a few minutes so so really it's
not just rivers being conduits but also really being modulators of this rather invisible size of
of plastic pollution we talk about particles that are defined to be smaller than five millimeters in
size but the majority of them as a smaller you you go in the in the size scale the more particles you
find so in particular on the lower scale of of the micro scale as as well as when you get into the
nano sphere you find increasing numbers of these fine particles so what have people found there
the studies that i'm mentioning here ours that we conducted in birmingham was at the river tame we
found particle numbers that were rather similar to what the colleagues found uh uh like alex horton
here a couple of years before in the thames so rather similar some colleagues in manchester found
one to almost two order of magnitude larger numbers of particles and then uh quite quite
a a wide range of particle numbers uh from rivers across the world being shown here as well
so there's quite a lot of variability and of course we expect there to be variability in this
emerging pollutant and how it's distributed in the world but we didn't expect that large variety
actually at such a small scale like even just between birmingham uh manchester and the
north and the thames south of us so what this uh comparison made us think of is how do we actually
sample how do we analyze microplastics in the environment in particular in rivers and we found
we don't have any real comparable methodology uh we all use different methods that makes the
intercomparability really uh very very limited and it really hinders how much we can compare what is
observed in the environment so we developed a program and that was with our a former post-doc
dr hollinel now working for cfas who really pioneered that development of a very easy to
use easy enough to use that it can be used by by citizen scientists around the world
methodology to go out and sample micro plastics from river water and from river sediments and we
started the 100 plastic rivers project that's funded by the lava home trust uh globally
trying to create a benchmark of microplastic pollution in rivers around the world
we work with a fantastic charity the clean seas odyssey that works a lot with citizen scientists
and did do that along the the general coast of the the british channel both the uk and the french
sides uh basically better testing that methodology with us which was fantastic and and we are very
grateful for their support there and that led to really fantastic findings in particular in in the
estuaries of some of the larger rivers discharging into the british channel as well as in some of the
more remote areas like the silly ielts here where where we could actually show that that methodology
that holly developed there co-developed there with a whole range of colleagues
works really nicely to identify some real hot spots of microplastic pollution but also
is uh sensitive enough to pick up the differences in particle size distributions and different types
of polymers etc and their cross-contamination which is a huge issue if you work with this
type of pollutant can be kept quite low we have since then rolled out this program
globally and we are working towards developing and establishing this really first a baseline
of global microplastic pollution and that's that's really important but what does it tell us it gives
us a snapshot of how uh spatially distributed this this otherwise invisible uh pollutants in in
surface waters and their sediments are we wanted to go a bit further we wanted to understand also
how they behave not just how they are distributed but why they are distributed in in in a specific
way and i'll show you here it's a very uh fresh outcomes of a rather epic survey where we got
support from a lot of colleagues in in india as well as in the uk and globally to actually
sample just before covet hit the world in the post-monsoon period of the year 2019 uh
more than a two and a half thousand kilometers of the mighty uh ganga river in india and sampling
more than 80 locations along the course of the main stem of the ganga and its main tributaries
microplastic pollution uh in surface waters and in sediment and what i want to show you here is
basically a couple of hot spots we identified that some of them like in the midstream sections and
in the downstream sections aren't locations where we would anticipate that we would anticipate that
this particulate pollutant is is accumulating downstream but we found some very distinct
hotspots in the midstream and as well as in the upper midstream sections that then i followed the
river flows from the top left to the bottom right that are followed by some sections that are a bit
less polluted and that really made us very much aware of the legacy the spatial legacy that exists
for some real hot spots of sources where where you get the inputs of microplastic pollution and how
far they are actually transported downstream and how quickly that happens and that maybe
they have to rethink some of our concepts of how long lasting these uh pollutants are
and and also how large the catchment areas that actually contributes to that plastic that end up
in the ocean because so far people have mainly focused onto rivers in their coastal areas
we we combined that observations with some modeling results uh here a model that we run
together with a colleague and friend jose gomez vallis from vanderbilt university in in the us
where where we simulate microplastic pollution in rivers and you see the catchment of the the ganges
just here around the world and and what we did show there is that the majority of microplastic
pollution in this large rivers is actually accreted in 10 to 1000 kilometers away from the
coast which really indicates we have to we have to adopt the catchment approach and really start
focusing on rivers that are providing this uh to the eye invisible pollutant from much further far
the shore than initially it has been anticipated it also made us aware and you see the results of
the mekong river at catchment on the left and of the the ganga that i just talked about on the
right that made a surveyor there in that really large catchments does microplastic accumulate and
for alone quite dramatically looking into all the plastic that has been contributed in these
catchments in the last 70 years the model results are predicting and they are validated based on
observations as well that models they predict that less than three percent of these large
contributors of plastic to the ocean less than three percent of all the plastic that ever entered
that catchment has actually been discharged the majority is still sitting in the catchments in
particular in catchment sediments and it will take decades for some of them centuries to actually
bleed out of the catchment towards the oceans which really highlights
the legacy the pollution legacy of this invisible pollutant that we have already created as society
and i want to finish off you with some results of our post-doc uh dr jen drummond that she recently
uh published in science advances using a different type of a model a more stochastic approach
to quantifying how long and where in rivers their plastic resides in particular in the
stream bed sediments where it's flushed in through hybrid exchange and how long it takes
to actually transport with the sediment she averaged that in particular for the low order
stream section so that's a small contributors to flow in this big rivers that in that sections
the the main travel time is roughly seven years for a kilometer of of plastic to be further
transported downstream which makes you understand that for some of these streams that have more
than several f of several thousands kilometers of flow length it will take a really long time
for that plastic to be discharged out and we're focusing a lot of course also in
into the extreme behavior during flood events how we could get jumps during these times so
where are we going with this we are trying to further elucidate where
microplastic is transported in the subsurface yeah in line with with the theme of
this year's uh world water day we tried to make the invisible visible there focusing in a recently
started project to go with colleagues from roehampton university in london on the transport
of microplastic towards and within groundwater and also another project funded by the royal society
doing that and together with colleagues in the university of lyon focusing in birmingham
focusing on how small invertebrates are able to facilitate the faster transport of microplastics
into parts of the of the subsurface of rivers and their catchments where they are even less visible
and why are we doing that and i'm finishing with this well it i think we we have shown
that microplastics and microplastic pollution is only present you can't escape it whether you are
walking a street and you are inhaling it whether you are taking it up or through your food and and
your water and there's increasing evidence that microplastic pollution can have impacts not only
on the functioning of environments but also in our own health uh with additives potential additives
like like endocrine disrupting phthalates uh bisphenol a uh and others leeching from it
and it's something we need to start to understand where and when we are exposed to this uh invisible
uh pollutant so with this i would like to finish i thank you all for for attending uh
today's world water day uh session across our two campuses and would not like to finish without also
thanking this huge amount of of people early a lot of early career scientists and esteemed
colleagues around the world that have contributed to that work i've just been presenting thank you
super thank you very much stefan for a wonderful start to our world water
day uh making the invisible visible and i forgot to say before i introduced you to
that everyone is invited to add their questions to the chat or to the q a function so please do
add your questions in there and we will try and address them and one has come in already from uh
rodrigo maruzi who is asking he says many thanks for the brilliant presentation have you seen any
correlation between imperviousness in urban areas and microplastic pollution and how relevant is
stormwater for microplastic transport in urban areas yes so a lot of i mean i should have
said i hope i highlighted that this it's a really emerging field of research and there are a lot of
groups that are doing fantastic research on this uh worldwide there has been quite a bit of a focus
on the contributions of of stormwater runoff of storm sewer overflows uh uh and and other uh
urban infrastructure sustainable urban drainage infrastructure et cetera on contributions of
microplastic pollution particularly during storm events there was a a quite epic study in the bay
area in california that has identified storm sewers to be a main contributor to microplastic
pollution they are doing during storm events that uh might differ regionally it really depends on
the development of infrastructure as well and and why large parts of the world you don't have
a similarly developed storms to a network as it has been uh investigated there but we know we
are absolutely correct that there is a strong relationship with runoff from uh sealed areas
one also has to highlight as a community we still struggle to resolve there's an even more invisible
part of this microplastic particles or that that is related to runoff from roads in particular uh
car tire and brake wear and tear particles are really hard to to find in the environment because
most of them of the methods that we are using are optical methods ftir and raman spectroscopy
are relatively well established to pick up a lot of these particles but they they still fail to
pick up uh this car tire uh wear and tear and uh brake wear and tear particles so synthetic rubbers
mainly but also some microplastics which are assumed to to constitute more than thirty percent
of the total global burden and and and that's an area where there's a lot of research focusing on
at the moment in order to make this even more invisible part more more visible because a lot
of that is related to runoff from impermeable services services as you rightly mentioned
super thank you um a couple more questions come in then so from ben howard is there any potential to
remediate microplastics from river sediments and do we have mechanisms already and is it practical
to do so yeah these are three really really challenging questions thanks ben uh they are
pioneered there's quite a bit of pioneering work going on with solutions none of them really have
have a field applications there are suggestions of uh bubble corridors at the mouths of of large
rivers that are basically uh bringing up a lot of the floating or suspended microplastics it
wouldn't remove microplastic from the sediment but they they would capture what is what is floating
in the river and then you might be able to capture that at the surface energy demand
of that is of course critical so i'm not sure how feasible that will be there are there are thoughts
of people starting to think what's happening to that sediment that is mined in particular many uh
asian rivers many of the finer sediments the sun's because with that you take out microplastics that
sediment goes mainly into construction so what's happening to that what does that mean for the life
cycle of plastic there there's potential uh uh uh and their initial discussions on going out how uh
uh potentially streambed sediments could could help to trap microplastics for for a longer time
and and there's been a lot of uh restoration work going into uh the development of of features that
enhance this hyperbaric exchange that jan drummond the last piece of work that i did show has been
researching a lot uh how that can be enhanced and reverse how you can actually enhance a flow of
surface water into sediments that would bring also more particles into sediments it's questionable
is that something you want what are the consequences of that there's a big concern about
unintended consequences what's the impact on on this uh uh food webs in that interface between uh
sediment and and water as well so the short answer is there are unfortunately while there are
methods to retain and and collect macro plastic in particular floating microplastics from rivers
and from the oceans and the vet also reduce the amount of microplastics that is still produced
secondarily from that macroplastic that are in the environment that that happens and i
think that happens quite efficiently but we don't have yet similar methodologies for for
microplastics that are already out in the environment a lot of work to do there super
um and another question then from michael mackin um who says you talk of citizen scientists and
then what have you done to encourage their involvement in this sort of work
that's a really great question and and maybe not well we were surprised but
maybe we shouldn't have been it doesn't need any encouragement it seems to be uh
a topic we recently had had a fantastic discussion around that while a lot of environmental problems
and challenges that we are facing as society are creating uh uh well not not necessarily are
creating consensus but already uh uh devising uh if you think about uh a politization of a lot of
of of research we don't see that at least not yet when it comes to plastic pollution a lot of people
are extremely keen and won't want to get involved in that and when a birmingham team uh uh uh
started the birmingham an action campaign uh esau is leading involved in that as well and a whole
a range of of fantastic early career researchers in birmingham where we were overwhelmed by the
response of of citizen scientists that wanted to contribute and and help with that program and i
think that is an experience that is shared with many colleagues it's it's and and i i i credit uh
some some programs like david attenborough's blue planet for that it really really hit
down the message fantastically of of what a challenge we are facing as society and and and
uh i think people are eager to contribute and to help we just have to learn to generalize that
that eagerness properly and and and best use it and i think there's still a lot to learn in our
academic community uh but yeah we didn't have to encourage that at all we were rather overwhelmed
by by the enthusiasm of of citizen scientists that that want to contribute and and industry
colleagues and friends in industry that want to be part of the solution
super thank you very much stefan okay i don't see any further questions at the minute but we will
have um a panel discussion with stefan in a little while so if there are further questions please do
continue to type them into the q a and if you have questions for for chris who's on his presentation
please do type them in now as well and so our next speaker then is is dr chris bradley who
is an associate professor at the university of birmingham and his research is on hydrogenomics
of floodplain wetlands and it seeks to advance ways to investigate the hydrology of low land
floodplain wetlands and includes modeling of shallow ground water flows and river aquifer
interaction and he has been very involved in the development of fluorescent probes
and sensors and specific research projects have included modeling of transient water
table variation on flood plant wetlands using the usgs groundwater modeling program mod flow
and using fluorescent approaches uh chris's research has also explored microbial water quality
in sewage impact rivers and ground waters and also as part of his role at uob dubai chris is leading
the establishment of the msc water resources management program and which will introduce
students to the key principles of water management to mitigate the impact of these pressures and help
in achieving the un's sustainable development goals relating to clean water and sanitation
and today as part of our world water day 2022 chris will talk about water and health a time
for new solutions over to you chris and don't forget to put your questions in the q a thank you
that's great well thanks so much indeed insults and good morning from
university birmingham to dubai it's um stefan i think it's given that some excellent introduction
to what's like the scope of water and i think we need to acknowledge that it really is very much
an interdisciplinary approach that's required and i'm sort of coming at water as a background as a
physical geographer and so i'm very pleased to be the workings of dubai on the development of a new
bsc physical geography program and we're also developing as they sort of a new water resources
management msc what i want to talk about today is um to to give a broad overview of some of
the research that um a number of us have been engaged with over a number of years at sort of
birmingham it's um we've been using environmental fluorescence to look at water in new ways and as
stefan was talking i was trying to think of how i could segue uh water and health onto his um
presentation and really what i want to focus on is it's demonstrate and perhaps have introduced
to some of you the potential to use environmental fluorescence to look at water into new ways
and so when we look at water and have given the the nature of world war today we we take
for granted the water that we we have in many parts of the world when we turn the tap as it
showed on the left-hand side groundwater again which is the theme for world war today is um
taken for granted but we have um globally enormous problems with poor water quality it affects
public health certainly currently in the um um many parts of the world um but also infects
environmental health and i'd like to take a very broad look at some health from both
the perspective of the impacts on the environment but also public health as well so for some context
here some of the work that we've been doing um recently into birmingham has been sort of looking
at the the impacts of combined sewer overflows where when we're looking at some river systems
and we're looking at the nature of the the urban drainage nets then the sewers during storm events
are incredibly important to the conduits for our water movement both for accommodating uh storm
flows of recent precipitation but also uh serving a function for uh um for sewage for transmission
and so in the middle image there there we have a shop from a recent urban flood event
in the in the city of birmingham equally within birmingham we have some problems with very super
water quality in certain rivers particularly when the combined suit overflows for discharge
if we were to look so globally um there is an incredibly importance of widespread motivation
for looking at water for looking at the number of people that are affected by problems of either too
much water or too little water or water that is too um too poor in terms of quality so if we're
focusing very much on a device and perspective we might um focus on the implications of the
drought and thinking about what the um what the potential source of our potable waters might be
if we're looking in um to areas of globally we might sort of think about the
the effects of poor um sanitation um and as you see here from the the numbers of
people potentially affected by adequate water and sanitation are by as much as 700 000 ounce people
also water is sort of fundamentally threatened potentially by natural disasters and conflict of
whatever's of nature and we can look at some water again from a disciplinary perspective trying to to
capture the variability into the precipitation evapotranspiration and thinking how that might
have changed look into the future but equally it's essential we focus on what the economic damage is
if insufficient water is available or if that water is um essentially of too poor quality to
be uh to be used and the estimates have given here for economic damage are um well in terms
of flooding so 31 billions of us dollars um in terms of earthquakes and some damage at 30 billion
if we're we are looking at this from a sort of a developed world perspective we we have
a really long history of looking at water into new ways and i think this particular slide um
perhaps it relates to some of the stefan's waves of looking at water into new ways and making the
invisibles invisible because almost for 200 years or so at the go there was a considerable problem
with water supply in cities like well birmingham but also into london and i find it fascinating of
looking at cartoons like this from 1826 where when you look at the nature of the cartoon we have a
lady who's looking at her cup of tea but she's looking at it
through a magnifying glass and what she sees when she's looking at it through the magnifying glass
is really sort of quite a wide variety of sort of fauna which through the 19th century became
whether it was recognized were having an impact on human health so the priority in terms of the
um what's the engineering approach to looking for water through the 19th century
was to improve the provision of clean drinking water but also to think about how
sewage could be could be treated and problems of contamination of possible water supplies could be
resolved as we've seen later we still have a problem with impacts of poor water quality in
cities likes of london city's likes of birmingham because of the interconnections between the
sewage system and the natural drainage system elsewhere though we have today a significance
of proportions of the population in some countries that are impacted by problems of
poor water quality and this data taken from a landsat sort of synthesis of water pollution
problems suggests that if we're looking at central africa in some countries like um
likes of chad we can have numbers of deaths per 100 000 population in excess of 100. if we
look at the situation within countries like the united kingdom um the situation isn't ideal so
deaths between five to twenty per hundred thousand the population the situation in the united arab
emirates where we are at the moment is actually a little bit better between one to four um
hundred thousand the population and so the the situation then with respect to looking at water
pollution is um is different so clearly it's a geographical context it's um it relates to the
way in which the people actually access there's a clean drinking water supplies it's the way in
which they store the foods potentially within the individual community or the household and they're
also impacted by the treatment of wastewater and sewage and so with some colleagues um in
the medical school we've been looking for example um samira miniski holland that's a problem scenes
of gambia and we um mentioned later on we're um at present so working in zavali looking at some
new approaches to quantify the extent of water pollution problems in the individual household
so when we um sort of look at these wider water quality problems are links between the water and
health we can identify classic examples around the world where there's been a significant investment
in the water infrastructure we can look into countries like from south africa
where provision of cleansing drinking water is provided routinely for small communities
we have problems elsewhere in um say the indian subcontinent in southeast asia where there are
very real problems in terms of people accessing waters from the local rivers that are very heavily
contaminated in some cases and in which the case they might be heavily reliant on the abstraction
of shallow ground waters as we see with the image on the on the right hand side well over the last
um 15 years or so so now it's at birmingham we've been sort of trialling the the use of
environmental fluorescence to look at the water um into different ways to look at it into real time
tried to do what the lady from the river thames water was doing in 1826
to see what the composition of that water might be to see whether that water might be sort of
safe to drink and to understand something about the pathways that the waters might be so taking
as it passes through catchments out of different scales and essentially what we're doing here is um
looking at the water in some new ways we're looking at so trying to quantify the fluorescence
of the water and recognizing that when we look out for the water many substances thrusts will give
outs of radiation energy at wavelengths of light that we can't see um until very recently
and that the our ability to look at the the energy emitted was relatively limited um but
in recent years we're able to use advances in optical technology to look at some fluorescence
of different wavelengths and relate that to the microbial composition of the water
so what's what is fluorescence and essentially fluorescence is a
physical processes that occurs that when a molecule absorbs a high-energy photon
um the the electron within the the orbit around the the molecule is raised to a higher um
orbit and re-emits a lower energy photon with a longer wavelength as it then
relaxes normally the absorbance is in the ultraviolet and the emitted light is in
the visible range but that's a varies depending upon the particular molecule
so the sort of less molecules that we can see in the water environment it includes some humic
matter inclusive chlorophyll it includes some proteins that depending upon the um the energy of
the light that we shine to the water we should be able to to characterize the individual molecules
that are so visible within that's a water particle and the nature of the fluorescence emitted varies
depending upon the molecular composition of the um of the um water that we're considering
so what we can now do we can use some take advantage of improvements in technology
to map fluorescence or to map particle space and what we don't see in this map is looking at the
the fluorescence intensity of untreated wastewater acts of different wavelengths so we have here an
image showing the um energy or excitation energies going from 220 nanometers to 400 nanometers
along the x-axis and then the emitted energy is shown on the y-axis from 300 to 500 nanometers
we can look at that as a 3d plot we can also look at that as a 2d plot and by using that
technology like this we're able to unpick the the composition of the water and ideally have a better
understanding of the organic molecules within the water that are responsible for that fluorescence
so the sort of wavelengths that we see we see microbial material here um shown on the on the
right hand side we see humic and fulvic substances we see fluorescence widening agents we see
chlorophyll shown on the right hand side and a plot like this could be sort of generated in about
10 seconds or so on a benchtop barometer but what we can also do now is that we can go to individual
wavelength pairs and use in-situ technology to see how the fluorescent signature at a particular xy
point varies in time and that enables us to get us a better idea of how some of these individual
molecules might vary um in a river depending upon the flow characteristics
or how um catchment processes vary during an individual airflow event
so the improvements of technology that we see we see some mass-produced instruments we see off the
shelf instruments that have them the ability to look at water into new ways
and we're able to produce optical maps in um well in seconds that took more than 50 minutes
a decade or so ago and about two hours in the 1980s and what we also are able to do now is to
make use of new advances in terms of sensors that are uh much more supportable so we can go out into
the developing the world's perspective we can look at the real world characteristics of the water
and we can use those sort of led sources within in-situ sort of sensors
so the sort of work that we've been doing this over the last of 10 years or so has been sort
of using instruments like this which is an smf 4 that was manufactured by safe instruments to
go out into different catchments in south africa to look at the relationship between
the microbial composition of water and some problems like like sewage or industrial
effluent what we did in this particular study was look at how we could relate the fluorescence
of the waters to lab counts of e coli and as we see with the the image here there's a
there's a fair amount of the noise in the relationship between e coli and the presence
intensity but as um catchment hydraulics we can look at try to understand what the
compounding influences might be that can explain that variability in the real world
um so part of that from south africans would study we were exploring some rivers like the um
river in south africa it's a peterborough iceberg going through down to durban we were looking at
some relatives of rural sort of catchments of rivers that in some cases were quite turbid and
we're also sort of looking at some variations in water quality in the urban area of the town where
of durban where we were seeing how in a relatively small urban river there were
quite some marked variations in the in the fluorescence and in the e coli um counts
but to a certain extent might actually maps the um also the variation names of microplastics or
ends of other contaminations that reflect the nature of the catchment psychological process
so when we sort of unpick some of the variability we have um a of simple and sort of predictable
sort of relationship between fluorescence and e coli um that varies depending upon where in
the catchment we are and varies depending upon how turbid the water is as we see in the lower
left image and there is also most importantly depending upon the the nature of the widest
attachments and the uh the lower right image shows probably one of the most um unpleasant bits
of field work that i did where we were actually sampling behind a just by a combined to overflow
um it was near a um a settlement where the perhaps say practices of sanitation weren't uh weren't
ideal and it were points like this that we're having um counts of states of e coli that were
orders of magnitude higher than they were in the upper catchment
and so globally now there's some this technology has been taken up in a number of studies where
people have sought to focus on the the correlation between fluorescence individual wavelength pairs
and um and e coli it's had some particular applications for sort of groundwater uh given
that the the actual surrounding to confounding influences are a little bit less on the uh
fluorescence or signature um but it also enables us to um to actually reflect on the nature of
the ways in which of um individual groundwater absolute science might be recharged it reflects
perhaps the nature of which waters in some cases might be um passing through rapidly
through the lines of groundwater's body and that might explain um local increases in e coli
so what we've um well i think it's important to recognize is that when we're using those in situ
those sums of field-based sensors we're only looking at one point one xy point in optical space
and what we're seeking to do now is to unpick more of the variability that we see and that's
the composition of water looking at the full what we call excitation and emission matrices
to look across optical space to see how some of the the individual fluorophores or the
the um the composition of the water might vary through a catchment going from headwaters
downstream but also during individual flow events where we can expect the actual composition of the
waters might to vary so in an urban catchment for example during the flow events we might see
an initial impact ons of the water quality that reflects the initial pathways that water takes
and then the nature of the urban drainage system uh before we subsequently get a dilution of eggs
um so with them to kill carbons of david hanna um we did a review of um
looking at the um the water qualities are very close to the uh edge persons of campus
on the borne brook looking at the nature of um of the organic material composition of the water
using um in-situ sensors to try to unpick what the variability of the um like the composition the
water was and looking at some trends between sort of high flows and low flows thinking also about
the the seas and also trends that one might expect to see and what we're sort of doing at the at the
moment with survivor we're um we're looking at how we can take some of that fluorescence later to
relate to the changes in specifically into the eco lines of trying to to understand how it's possible
to use fluorescence in real sort of catchments and the images on the on the right-hand side side here
are taken from um mid-reaches of the the river ray um in in birmingham um it's the same sort
of shots but some in the upper image it's drawing a period of relatives of low flow the lower image
is one where flows are a little bit higher but the confounding influence here is that at long bridge
there's been some sort of recent construction uh rates of um significant amounts of sediments
are mobilized the um the contractors um made no attempt to trap the uh the sediments and we have
some very high rates of suspended sediments are passing through which doesn't actually
equate into its of high levels of microbial contamination but leads to some complications
interpreting the uh the fluorescent sort of signal because of what we call inner filter effects
um so the point out of emphasize here really is that we we need to think and i say this as
a geographer we need to think in terms of the temple and spatial variability we need to think
about some discontinuities in the way in which the water moves through the system and something like
fluorescence actually provides a tool to unpick a little bit more of almost like our understanding
of non-stationarity instead of hydrology and the way in which um individual water flow pathways
might switch on and off during an individual flow event and how that might also explain some of the
changes that we see and that's a cocktail of water that's moving through the at the urban system
um what we're um also doing with um with samira and um both in the gambia it's a word that we're
writing up so shortly and instead of marley is looking to see how we can
go into areas where we can use this technology to suggest whether there is a um whether water
might potentially be safe to drink or or not to identify areas perhaps where there might be
some contamination the water transmission sort of systems the water distributions or systems
we um we're moving beyond the smf iv that we use in south africa to to have um well
hopefully have some instruments that have a better minimum detection limit because the
confoundings of problems at the moment really with fluorescence and the sensors we're using is
the well well the the minimum detection limit isn't sort of negligible and so there is that
sort of threshold of background fluorescence um where um we're not necessarily so confident of
the correlation with uh with e coli so that's sort of work on the progress and we we are um
suggested to working into africa at the moment to try to impact some of those relationships
so in summary then we use resonance spectroscopy to provide a rapid almost instantaneous indication
of things like total organic carbon bod we can use some fluorescence in different ways as a
portable or an in-situ sort of sensor what we do need to do is um address that to actually think
about some ways new ways of looking at water um to move beyond perhaps to use the magnifying glass
to think about the ways in which we can use the technologies into different ways to look at the
better process understanding of what's happening in certain catchments and understand a little bit
more about the variability the relationship between fluorescence and bacterial counts
um and the final point there is that what we can also do from a psychophysical perspective
is useful for essence to um look in real time at some of the problems of poor water quality
and that has some sort of quite exciting implications from a uk perspective where
there's interest in terms of bathing water quality where there might be some problems
with combines through overflow discharges into building waters around the coast um and so using
fluorescence we should be able to identify whether um whether there are confounding problems with
points or diffuse sources of pollution within this attachment or problems related to that turbidity
but i'll um i'll finish there and then happy to try to answer any questions
thank you chris that was wonderful um we have a first question in and i'm sure others will um
will come in now over the next few minutes um so the first question then was from pippa tucker and
she asks are there any problems with interference or selectivity yeah so um i mean that's a that's
a really good sort of question i mean there are clearly some interference or problems and that's
why groundwater is um it's perhaps some of them the um the more easier associations between e coli
and fluorescence relate to say groundwater because there isn't that surroundings of influence of um
stupidity might say one example um there are also difficulties in terms of making the associations
between some particular fluorescence in particular sort of microbial um um composition and um
i mean one example we look at the association between fluorescence at a particular wavelength
and e coli um but unfortunately hydrocarbons for us at the same time wavelength and so that it's
really important to think about what the wider process might be and what the errors might be
in terms of looking at association between june fluorescence and e coli um the other
sort of problem this is some sort of work that's um appearance of leading on is that there are also
first further um confounding influences depending upon the nature of the sediment um and so we could
um we could look at hypothetical catchments and the um the the composition the suspended
sediment might vary and which would vary and that could influence the the present signal as well
so there's an awful lot of noise there um i mean what we're hoping is that when we're moving to to
work in a perhaps a more household area into africa um some of that's a wider influences
that we see and say in rivers is lacking and we should have a better sort of correlation there
super um it did just occur to me linking your and stefan's work and when you mention
the hydrocarbons then whether microplastics might interfere as well absolutely yeah i i mean we have
we have sort of thought about well i mean whether you can actually sort of look at some
fluorescence of microplastics i mean it's a it's a classic study i think for uh for eco lab because
the problem in the real world is that you actually can't filter out those wider environmentals
of influences but of course in a controlled environment where we have a series of flumes
we could actually potentially succeed it with potential microplastics and so look at the signal
um but yeah but i i mean the short answer is yes but um um but what what you would do also sort
of see when you're using some of these in situ sort of sensors you see quite a bit of the noise
within the the signal which again we'd normally average out and so it's trying to understand what
the nature of that sort of noise might be whether it reflects the individual or the composition of
individual ally pots of water as they're passing through or whether it's a problem of perhaps of
local hydraulics depending upon where the sensor is sitting above the riverbed super okay another
challenging question from ben um ben asks how do you separate the fluorescent signal of e coli from
that of other microbial species that fluoresce at similar excitation emission pairs and could
this explain some of the noise in the relationship between fluorescence intensity and e coli number
absolutely well i mean that's our explanation for the um for that sort of noise and that's
also africans of data set i mean that's i mean what we're finding there is that stupidity was
actually it's a really good predictor and so i mean what what always are doing at this
stage is look at the uh the correlation between um the fluorescence of a particular wavelength pair
and sort of lab counts of e coli um i mean there's a question i guess of whether you you're actually
trying to improve the correlations or i mean some have actually suggested that um e coli might sorry
in this situ observations of fluorescence might be a a better indication of microbial contamination
than lab accounts given that lab counts might take sort of 24 hours or so to process and um
i'm supposed to work at the um universities west of england for example which is suggesting that um
reynolds group that you can sort of look at the fluorescence and that gives you an idea
of microbial activity um which can be a um very useful sort of indicator of um almost like the
widest composition of lots of water um the the other perhaps way to come back to ben said a
question i i mean what what i think we could do is if we had to take more data where we had the full
excitation emission matrices then we might actually be able to unpick some of that
variability but stupidity certainly with the south african study was the main confounding
influence okay um and then we have a question again from rodrigo maruzi who says many thanks
for your presentation e coli may naturally decay have you tested this tech for pathogens
other than e coli and he asked specifically for cryptosporidium parvum oocytes oocytes
the short answer is no i i haven't i mean in south africa we were looking into total cold
forms as well but it was basically it was a cold alert system that we were using and um and so and
which is the standard um there's a process that public health um england might have used i'd i
have given that i gave this a presentation in um in brazil a few years ago and there was a dutch
colleague there who was was actually looking at um emerging contaminants and actually looking at
a whole range of different microbial communities and it was a little bit like um was like the
analogy of coming back to that lady with the tea cup and some thames water that the more you look
the more there is there and we are looking at e coli essentially because we that's the
requirement that some so there's a public health monitoring but um there's an awful lot i think
that we could do to focus on other um so microbes and other elements that's a microbial community
super and i have what might be a relatively naive question but i'm going to ask it anyway and do
you think these sorts of fluorescent probes could be used to look more broadly at edna for example
so it's a vda it's um
environmental dna sorry could they be used
i've i really couldn't answer that actually i'm i'm sort of looking across the stephan but um
i died i really um i really don't know i mean what what personally as a nun sort of chemist coming at
this one what i found was very helpful is thinking about say what's actually for essence going
back to the physical principles of where these electrons are sort of um orbiting so i i think
we would be able to go back to that sort of basic sort of chemistry and say well what should we
expect to see um but i i i honestly wouldn't be able to answer that sorry okay no worries at all
no worries at all okay thank you very much chris for a wonderful presentation and then perhaps
we can get stefan to come back up as well and we can um maybe stop sharing and segue into a
a panel discussion with both of you so don't go anywhere chris perfect perfect okay so we have a
a topic broadly for um the 2022 world water day of making the invisible visible and groundwater
in particular and i think chris you mentioned at the start of your talk that people take their
groundwater is taken for granted and i wonder do you have any thoughts about why this might be and
you know how it arose that we that we take it for granted
yeah i'm so very very concerned i'm speaking as a perhaps more of a surface board or hydrology
sort of person and if i'm looking at this from a geographical sort of perspective i i think there
is that's a feeling that some groundwater is out of sight out of mind and um it is
really important i think to reflect on where the water comes when we turn over open this will tap
and in many parts of the world i mean that's a ground that that would be the groundwater and so
from a uk perspective my sort of family is from the east midlands and um more of the water coming
out of the tap is from the groundwater and so when we sort of boil the water in the cattle you
see the calcium carbonates of deposits instead of birmingham um i mean we have really goods of welsh
rainwater and so we don't necessarily have that's a problem but there are other parts of the country
lily where's the groundwater is very important and then into dubai
of course the water that we have at the tap is um well if you look at the source it's
um it's come from the gulf and it's gone through a very expensive desalination to the process
um so it's a groundwater i think it's right to focus on that but from a water perspective
um it's one of the um was one of a number of sources of outer potables with drinking water
stefan any thoughts from you on why groundwater might be taken for granted or
less that the the general public might have less of awareness of its its importance
i i think that chris is absolutely right and and what he mentioned there's a definitely a bit of
this element it's it's it's out of sight so it's out of mind and that also means when there are
changes both in quantity as well as in quality they they appear
sometimes less uh uh pronounced and and often with a quite significant time lag that means uh they're
often not directly attributed to a specific impact if you if you see your surface water levels
dropping in summer because it's actually pretty dry you you attribute that to the weather if uh
if your surface water levels are rising uh during a flat you actually attribute that to the recent
fall of precipitation and and the same with chris had a great example there of of uh the
impact of some uh construction on on on the turbidity of of of the water right and and
uh and so so a lot of that has immediate effect and and is quite visible whereas for
groundwater it's often less visible you need to look you know you can of course
see responses in groundwater boreholes and but but you see them uh differently and and you often see
them with a real time lag and we know that for for uh many pollutants like we talked about the
uh groundwater uh time bomb of nitrate and that's something for that that we have as a community
been talking about for for a long time there have been papers published more than 10 years ago on
that and we just start to think of pollutants more emerging pollutants pharmaceuticals
microplastics etc what's the residence time when when do we see that response in waters
we start seeing it uh for many of them but how long has has actually that that pollutant uh
traveled in in until it uh with a recharge until it it hits the ground produce and that often means
that there's no direct association anymore with actually the polluting event with that dry summer
with that significant uh amount of precipitation that fell over over a certain period or so and i
i uh i think i think that's uh i don't want to put anyone on the spot but i just see doris is
is coming on here as well knows a lot about brown water and i don't know doris if it is because he
wanted to to add something as well may i just introduce you first doris so yeah absolutely
yeah no perfect so i i noticed doris had had turned on her camera as well and so doris is a
research associate at the university of bristol and an honorary research fellow here at the
university of birmingham and as stefan said she is an expert in all things groundwater management so
please doris if you have any any thoughts as well on on this important topic um of why we think
it might be less in the public conscience or less understood by the ordinary person
yeah thanks i hope the signal is good enough in the garden uh i just took the most of the nice
weather here um so thanks to zelda and stefan and and chris um so i just i just thought to add uh
something really i think compared to surface water groundwater is very much hidden away is in this
aquifer so whenever like when people are using it they basically either have a spring and that
naturally occurs so it's really hard to determine or maybe a pipe and if there's over pressure it
means it actually bursts out so um it's hard to see how much water is available and it's very
hard to see what's the consequence of your water compared to say the surface water reservoir where
you can literally see the water level drop um and and this this makes it harder to say
you're using too much you're using too little this is available that's not available now
you're mining now you're not watch the quality because consequences outside of your catchments
outside of your neighborhood or municipality uh are going to degradation so i think that's why
i think that contributes to the trouble to the problem that it's taken for granted um simply
because it's it's literally more hidden away um yeah and and not used as the first instance i
know very few regions in the world where they first saw us groundwater before surface water
um so it's very often the the combination of the two okay so it's it's used more typically when
reservoirs surface water reservoirs are are low and then we or or not available uh if there are no
rivers like in denmark it's 100 percent sourced by groundwater and that's basically because um
that's an that's a that's a very allevial uh very suitable aquifer for it um yeah and it depends
very much from from place to place what what kind of deposits there are what kind of aquifer
where the rivers are flowing how many people are living there what resources they have to
to manage or to use it so that leads very nicely then into into a next question which is sort of
if we you know if we need to raise awareness of the management of groundwater and
and we need to you know we need to think into the future where we're you know again we're seeing
much more visible um flooding events and drought events how can we connect the understanding of
the implications of those for for groundwater and you know i mean as a as a non-hydrologist i would
often say you know i'm being from ireland where it rains continuously i was you know if we could
capture the rain water or you know tax it as it comes over to the uk ireland would be the richest
country on the planet so you know are are there things we can be thinking about you know with
a more sort of hydrological cycle viewpoint and i put that to to all three of you and um
i don't know who'd like to start yeah i i i think because um so certainly again speaking for myself
as an ungrounded hydrologist so i think it's a really important sort of questions there and
i think as a hydrologist i'd say we do need to think better about the interconnections
of the hydrological cycle and that's to think about what the source of our rainfall is and
one of my sort of favorite questions is what's the start of the hydrological cycle and you
can answer that by looking at the isotopic composition and say it's when the waters first
evaporated um but some of the ground waters that we're using some fossil ground waters they might
be hundreds of years old and um they're a product of um lots of nets and precipitations of um
many um against hundreds of years ago and they're being abstracted at rates that
are unsustainable and so if we make too much use of lots of resources then
within a well potentially so very so quickly uh we might run out of water and then there's a really
good way to visualize that which is looking at the um the groundwater footprint and so but look it's
a current rates of recharge and what's the current rates of water loss are the other way i mean let's
press before i hand over to stefano and the other way i would suggest to look at this and this is
just purely from a personal perspective um so from the introduction that sorts of very kindly gave me
i mean i i have a wide variety of interests my phd was looking to wetland hydrology but
one of the most interesting things i've done in the last few years has been sort of working as a
advising um well i um the owner of a state home is of norfolk who's convinced that some the defend
his friend in the norfolk broads is affected by over abstraction of groundwater and the the
environment agency has spent so many millions of pounds developing a regional um groundwater model
um but there is insufficient i what some of us would argue understanding of what the
importance of the changes in the patterns of water abstraction might be on the groundwater dependent
ecosystems that we see in areas like outlines of norfolk and what we might be able to do there is
actually absolute better hydroecological models that enable us to quantify
um how important it is to maintain sufficient data groundwater recharge to
to support those systems but we also need to think very much about the nature of regions like that
as a as a wider catchment um linking into the ecology and the the further complication there
which i think we also have in the um into dubai in the uae is impacts of save rising sea level
and so some of these rivers some of these groundwater bodies might be affected by
saline intrusion if those aquifers are over abstracted and so the local farmer might
appreciate that when suddenly he can't use his uh his um sort of local well um say in the um
um so in the region to cultivate his irregulars of crops um but we need to
have some better ways of actually making sure that of different generations appreciates that
actually the way in which these subsurface water reservoirs have been used is is unsustainable
yeah i agree with fully with chris and i think there's a lot of work still to be done to to
raise awareness that that we're talking about the hydrological continuum and that ground waters and
surface water is is closely interconnected i mean what i said in the beginning that there
can be quite some time lag in the response that doesn't mean that there's no connectivity it
just means that quite often a signal whether that's a pollution signal or a response to an
abstraction potentially an over obstruction it's not immediately seen but it is it is there is that
connectivity and it will have have an impact and there's a lot of awareness to to be raised about
that and it's uh it's probably not just surprising that there's still so so much awareness to raise
about because as humans we don't understand for that long yet uh historically i was surprised as a
student to learn how how little time only has has passed since we started to understand that that
our rivers basically flow uh outside of periods of precipitation because they are they're basically
uh recharged by groundwater and and groundwater discharges is the main a a contributor to the
base flow of our rivers and and even in the uk uh uh many of the rivers uh uh during during summer
uh are heavily uh affected by the management of groundwater not just obstructions from surface
water but management of groundwater which of course the uk is a well-regulated uh country and
many other parts of the world are not and that's where of course there's a lot
of source of for conflict as well the conflict that we are already seeing and while sometimes
our viewpoint when it comes to international use of of water resources across borders because the
water cycle doesn't doesn't care about any any political borders and boundaries right
we tend to focus on the large rivers but of course there are many large aquifers that are across
cutting boundaries and and the region we are in in in the arabian peninsula and the middle east this
we see that a lot the uae itself doesn't doesn't uh uh rely on groundwater a lot what does not as
chris said in the beginning a a larger contributor to the water water mixture but other parts of
course of the middle east are and and obstructions from aquifers in in of one country have an impact
on on the availability of groundwater in another country and that's something again where this
invisibility because you and the time lag have have quite an impact uh on how decisions are
made and and how how our responses are designed to to certain management and practice as well
doris did you want to add um yeah yeah perhaps well i would i would
agree with with stefan and chris i'm just thinking like so what chris was saying about
the that when you are investigating the stores and and like the groundwater availability cross
regions and there's also highlights to what stefan said it's that there are few models of
representations availa available for groundwater whether they're abstract or what are they applied
and then if they are accessible to the public or to the regulator in the first place you can ask
oh did they actually include management is this historic abstractions is this current obstructions
are there any management is it is a dynamic component is it static component because of
the complexity of building a model in the first place um there are very few tools available
um to to address both both the interaction of surface water groundwater the availability of
groundwater and then how we how we change those two um and so there are for the uk there are
a couple of national uh models available but literally just came out in the last two years
um and and and across the world this is this is quite an emerging topic really um and when
thinking of your initial question is old about too little and too much at the wrong times
you were saying could we not store all the water of ireland and sell it off well this is this is i
think this is a brilliant question and a very nice way of conceptualizing it but yes this happens
so so people are looking into flexible flexible operations integrating surface water ground water
storing water seagulls sorry i'm in bristol um so uh integrating surface water high
uh groundwater looking into storing water either in reservoirs in in aquifers so that's what um
uh shin yinchin is going to talk about or has talked about many people here are aware this
is managed for recharge happening in california big scales smaller skills here in the in the uk
but yeah there's also there's a lot of transport already in in england
water from birmingham water drinking water in birmingham comes from whales
and um and yeah so there's a whole suit of of options really yeah right it does feel
a bit like our you know my grandparents our grandparents generation seemed to know more
because i remember sort of my grandmother having you know big barrels that they collected the water
in and they use that water to water the garden because we didn't have a top with you know in a
hose so they were they were already much more i guess thoughtful in how they they managed
water or used water so um yeah i'm wondering whether rooftop collection systems or under
even under you know as part of building our houses underground rain capture systems and things should
be a you know should we go back to those sorts of ideas and things so or well with an updated twist
so yeah absolutely right there so then and just just to bring in a a final point when
we are revisiting as as society the the the approaches of managed aquifer recharge that
that doris has just mentioned right but it's the principle is not new right the principle is
is has been there for for for centuries i mean people have not done it at the large
technological scale as as we are doing it and and uh are expanding or doing it uh globally but it's
it's something that that cultures uh almost two thousand years ago or so have have done already
so it's it's uh with maybe not always the full understanding in into what uh aquifer in what time
of the water is recharging but they understood that retaining water in the landscape for longer
brings benefit during dry periods super and doris had just brought up another point that i was going
to raise which was the the sensors tracers and and the simulations and models and and chris you
had also mentioned you know isotope um tracking to sort of tell us the age of water and things
would you would any of you like to sort of tell us a little bit about you know how you think those
will will help going forward in terms of really understanding um yeah the implications of of
managed groundwater and how we better manage our groundwater
should i start and then yeah yeah i think i i think some really it was a really important
interesting sort of question i i i guess the um the difficulties whether we're talking this
from a research perspective whether we're talking in terms of say practicalities
and um if i was being sort of critical of what we've been doing over the perhaps the last of
100 or so years perhaps we have focused too much on some engineering solutions and you can look at
the ways in which people traditionally have used the world surgeons as you mentioned this all to
store water locally um i mean that could be really i i think making a mess well an immense
contribution in terms of reducing the demand of um force of um clean sort of treated outs
of water that we can sort of turn the tap and so um i mean there is a suggestion actually that um
we're treating water to such high qualities and then we're we're flushing so much
of down the down the toilet or through some dishwashers washing machines
or we're using it to um to keep the grass green onto golf course because and some gardens and so
the question then is well how do you um resolve those sort of problems and i i think ultimately
as individuals and consumers we we have to to think about the price that we should pay for the
water and um i know um i mean my father used to live in a relatively large house and um we found
that he could save 60 70 pounds a month just by moving onto a water meter um and so personally um
from a purely selfish little perspective um with a family of four and a terrorist house in birmingham
we we're making sure that we are paying according to our value of our property and if we had a water
meter we'd pay probably about three times as much as we do at the moment and so i i think the
emphasis there is perhaps thinking on um perhaps a cost model um it's not necessarily answering your
question so from say stable isotopes or models uh i think the i think we still have a way to go in
terms of using models in the sense that i think that the models are perhaps discipline specific
and that um but if we were to to look again now and say if we were to design how we should um
value the water resource in individual catchments then we might have a system that's actually quite
different from what we have at the moment um and there might be some parts of the world where we
recognize that we can't grow salad crops because of the perhaps the say the locals or climates
um but equally perhaps we can sort of look at ways in which we can change the focus of land use to
make sure it's appropriate for the climate rather than relying heavily onto the irrigation which
again can lead to problems of salinization and so on to further down the line and so it
i don't think there's an answer to your question though but although stefan might be able to uh um
i i i maybe would answer with the chambers plug for for for the presentations that we're having
this this afternoon because i think all all four of our experts have been using uh and are using uh
different types of traces to determine not just the age but also the origin of of water a lot so
andreas hartmann is a renowned uh cast hydrologist who who looks uh a lot into
particular the fast flow paths in in dual porosity systems in the subsurface and laura richards
has worked a lot with geochemical traces that tell us a lot about the more really uh geological
origin of of of waters and and uh work both work over very different time scales and adam ward was
uh uh just uh uh come on on camera as well has of course worked for a long time both with natural
as well as added races to better understand the mixing of surface and groundwater resources and
and doris a lot with natural traces in particular as well and and maybe i i think what all of this
so there's this really broad portfolio of of both natural tracers and and tracer said that we can
add into the environment in order to understand flow paths uh residence times i think there's
a big push in in the community towards understanding also where water resides for how
long water different water sources that are mixing and using some some reactive traces or smart
tracers for that and i think the real need for it is doris mentioned that it's really difficult to
to for on the modeling side to to to link up surface water and groundwater models and and
there's there are a couple of of very simple reasons for that and i think jan fleckenstein
a colleague of ours uh uh who works at the helmholtz center of of environmental research in
in germany did i think it was when he was still at uc davis uh come up with a very intuitive
nice graphic where i did show that uh if you look into the interconnectivity between groundwater and
surface water systems surface water systems are very much controlled by the temporal dynamics of
processes so they need to be able to represent and be responsive to fast changing processes whereas
uh that doesn't mean that they are not spatially distributed of course
they are but then these these responses are much more subdued in the subsurface
but whereas a spatial heterogeneity that comes in through variability and the geology etc place
again it doesn't mean that that doesn't exist on the surface of course we have topography etc as
well but it's combining this spatial and temporal dynamics in one model so their processes act at
well you could say from a millisecond to a millennial scale that is that is numerically
of course uh immensely difficult there have been massive uh developments and i think in
particular the data scientists and modelers uh modern developers in the community really push
uh uh this developments a lot i would maybe to be a bit provocative here say say now as well
pushed it almost so far that we can't have can't provide the data to in a meaningful way often
run that models because we can't we can't fill good models with data and then you end up with
uh with a rubbish in rubbish out output of of course of models quite often so so we
we we have to be able to also bring that tools like like chris uh talked about fluorescent uh
uh and and many others uh uh tools to to provide that spatial resolution and temporal resolution of
the data that we need to to actually bring that uh models together with surface and groundwater moons
super adam did you want to add anything yeah adam ward here um i just as we talk about how
our science advances sustainable management of this limited finite resource of groundwater
um i guess i also wanted to make a plug that all of the modeling and tech technological
engineering knowledge in the world isn't going to get us there unless we actually translate this
into meaningful policy um and you know so another need that maybe wasn't discussed in in that kind
of laundry list of advancements is actually how we as the scientists who are the physical
scientists perhaps who are studying this are integrating with social sciences and with managers
i would venture to say that globally much of our groundwater management occurs in a very top-down
way probably subscribing to something like hardin's tragedy of the commons as a
management philosophy we need government to save us from ruining ourselves and i just i feel some
obligation to also point out that although harden didn't win a nobel prize eleanor ostrom did with a
very different philosophy that started with the earliest of her work on groundwater management
and how commonpool resources can be successfully managed by local communities
working together in their shared interests and the pendulum has swung quite heavily toward a top-down
approach and perhaps actually helping communities understand their own resources
while not the flashiest of technological advances could be one of the most meaningful places we
put energies in sustainable management of our groundwater resources super thank you adam and
that actually reflects really well a comment we had from michael mackin also in the chat in the
question and answers who says the way to get water savings is education and behavior change and this
can be achieved by citizen involvement so really raising awareness and behavior change i think yeah
so just to to point out as well i didn't give adam a proper formal introduction but i will in the
afternoon but just to say that he's an associate professor at indiana university's o'neill school
of public and environmental affairs so obviously working with um translating research to policy is
part of his day-to-day bread and butter as well so we'll pick up a lot of these topics again in our
second section uh which will start in just over half an hour and we had one last question in the
um in the q a that was sort of a broader question but i might just sort of put it out there to to
see if we have any quick responses before we let people take a little bit of a break and then
for anyone who's interested over their coffee to have a look at the the leecy guang lecture
and but the question in the chat then was sort of how do you clean water so that you can assure
ensure it's used for for domestic use and i'm guessing that sort of in the absence of um managed
wastewater treatment so if we are collecting rainwater or collecting um surface water and
things how would we how might we make that suitable for domestic use chris since you
were working really on the the water quality for health and would you like to just take that first
i think i mean it has to be tailored to the environment and so depending upon what's like
the size of the community or the south side of the household um i mean there would be i
think some really good propriety of filtration systems that perhaps the level of the individual
household would be um would be appropriate um i mean if you're mindful of the um say potentially
contamination for safe locals of um groundwater boreholes again um perhaps think about possible
um impacts forms of lots of nitrates that stefan's mentioned um i mean you clearly do need to be able
to monitor and understand that sort of composition of water and it's both microbial but also that's a
physical chemical to properties um but i mean the tools are out there um what's um i should
say one two slides in from the south african sort of place i think what south africans have
suggested really is that you you can tailor some of the the water treatment systems to to deliver
really good sort of potable water to quite remote communities and so the science is there and they
are prioritizing the provision of acts of clean water um and then i hope so over time then some
improvements in sewage infrastructure and so on cancer to follow um but i think we want i mean i
do i mean the more i have looked at that sort of cartoon from 1826 the more i sometimes think we're
providing more and more engineering solutions well actually we're doing what the um um what
the engineers the victorian engineers who did 150 170 years ago and um perhaps there are ways
in which we can sort of think about say what's the realistics of locally and so think about it
working with nature a little bit more um but we have to understand the composition of water first
if i may i'll just briefly suggest that again it is a slightly technological solution but it is
sort of geared towards more local use there's a lot of research currently um on the use of
solar-powered desalination which is basically just distillation so it's it's sort of the equivalent
of boiling water but using solar power to to do that and then collecting the distilled water and
um but of course knowing what pollutants were in there first and you know making sure that
there still there isn't bacterial contamination of your collection um vessels and things like
that would also be be important for for you know making sure that it's it's actually potable water
um super so i am going to thank our panelists and our speakers from this morning session for
joining us live from dubai and then we shall take a short break for uh depending on where you are
coffee or an early lunch or uh just a break generally i am also um posting reposting the link
for the the lisa guang lecture so that was on groundwater um and managed aquifer recharge
and by professor yan zhang from the southern university of science and technology and really
interesting watch over your coffee if you and if you have time and so that's it from our dubai
part but i i guess stephan and chris will you be joining us for the for the next session as well
we we we will definitely join but but as uh uh participants yeah okay perfect super so enjoy your
coffee and dorison and adam we'll see you back here in half an hour for uh your presentations
and a further panel discussion and thank you everyone for joining us and we might play the the
lisa guang lecture um through this as well just in in the background while people are getting their
their coffees and things so perfect talk to you in half an hour thank you very much everyone
okay
okay perfect good so welcome back everyone and let me just see how the numbers are doing um yeah
we just give it another minute um for people to join us back again after the coffee break
um and then yeah we're missing one of our our speakers anyway welcome to part two of
our world water day 2022 and the theme of which is groundwater making the invisible visible okay
um so this morning we had um presentations from professor stefan krause and dr chris bradley and
i was chairing this morning session and then i'm joined by dr kieran kamis as co-chair for this
afternoon session and we have an exciting program of four speakers coming up um in this afternoon's
part and i will present the speakers individually in just a moment and we're absolutely delighted
to have them with us today but just before that i want to give a quick shout out to
uh professor david hanna who is also in dubai at the moment and he's at the expo at 2020 um
on the on the water themed week this week so if you're interested to see what he's doing
you can follow him on freshwater flows or you can have a look at expo 2020 dubai or followed by
people and planet so um yeah we had hoped we might be able to make a link to david there but it
proved a bit technologically challenging for us and for well for me in particular so i can just
about manage this um so we've just had a brief look for those of you over your coffee at the
um the lisa guang lecture that uh professor yan zheng gave us at the end of last year
also on the theme of groundwater and managed aquifer recharge so we thought it might be nice
just to to give people an opportunity to see that as well and then we had our presentations
as i said from stefan and chris this morning um so the four speakers that we have today um
are there our first up we have uh professor andreas hartman from the institute of groundwater
management at the technical university of dresden andreas did his msc and phd at the
university of freiburg in germany and his post doc at the university of bristol in the uk and
at mcgill university in canada from there he returned to freeburg and became a lecturer and
later an assistant professor with his own research group since october 2021 he's a
full professor of groundwater systems at the technical university of dresden in germany
his research mostly focuses on quantifying karst water resources by simulation tools and
that he applied at scales of individual caves up to entire continents and today he's going to
talk to us about fast flow into aquifers and its consequences for groundwater quality but before we
pass to andreas i thought we would introduce all of the speakers so then we'll have less
buffing back and forward between my screen and the speakers screens so our second presentation today
then will be from doris wendt who's a research associate at the university of bristol and an
honorary research fellow at the university of birmingham doris completed her phd at the
university of birmingham in march 2022 which was entitled from observing to managing and mitigating
hydrological droughts doris's research interests lie in managing the invisible groundwater
resources to increase resilience to climate extremes and in her talk doris will highlight
the power of groundwater management showing examples from various management strategies
promising success stories and recent advancements of socio hydrological modeling and her talk title
will be managing the invisible water resource of groundwater then we will have a presentation
from dr laura richards from the university of manchester she is the dame kathleen holland um
okay okay nope sorry we're just having slight technical difficulties
uh just bear with us okay that sounds better i'll keep going with my introductions then
um so laura is the dame kathleen alan renshaw research fellow in the department of earth
and environmental sciences at the university of manchester her research on groundwater processes
and remediation particularly as related to geogenic contaminants such as arsenic
and it's robustly informed by international field programmes and multidisciplinary collaborations
in south and southeast asia south america and sub-saharan africa and laura is going to talk
to us today about groundwater arsenic in bihar india distribution controls and remediation
approaches and then finally we will have a presentation from professor adam ward
from indiana university and he's at the o'neill school of public and environmental affairs
adam's research focuses on the exchange of water solutes energy and pollutants
between surface waters and ground waters adam uses a combination of field-based experiments
environmental observation and numerical modeling to quantify couplings between
physical biological and chemical systems and he applies this knowledge to predict water
quantity water quality and ecosystems responses his research portfolio also includes the study of
how we manage and regulate water resources in the face of changes including land use change
land management activities and climate change and today adam will talk about it will tell
us that groundwater is visible if we know what to look for so an exciting program of
presentations this afternoon and it is my great pleasure then to introduce professor andreas
hartmann from the institute of groundwater management at the technical university
of dresden and if i stop sharing them and pass over to you andreas you should be able to share
okay are you can you hear me now we hear you yes perfect okay so i'm gonna start screen share
all right okay so you should see what and we see your presentation perfect
the floor is yours all right okay so first of all happy world water day to everyone and thanks
to um to david and to stephen all the organizers for the invitation today i was really happy
that i could present some of my i would say not most recent work or very recent work um
i wasn't here in the morning because in fact i'm still on part-time parental leave and this
little lady is keeping me busy all day and i'm here with my um baby phone while she's sleeping
right now so if i disappear shortly after my talk please don't be angry with me as well and i'm sure
she will sleep during my talk and not because it's boring but she had a very busy morning and i will
speak today about um fast flow into aquifers and its consequences for groundwater quality
everyone who knows me knows what it will be about it will be about karst karst is a landform that is
very beautiful as you can see in these pictures it was um the the background of many um famous movies
so yeah this is a recent um king kong um movie that was taken some cast areas or cast island in
thailand this is a very nice cave in hungary um where sylvester stallone tried to land his plane
and unfortunately he paid and in the expendables too um i'm listening to somebody else so please
it would be nice if you could turn off your mic thank you and here you see um the azure gate in
gibraltar um which was in the background of game of thrones unfortunately um this gate is it's not
there anymore a storm um destroyed it so now you just have the freestanding rock and not the bridge
anymore and this is actually a very nice site because it's close to one of my study sites it's
a radio telescope in puerto rico i've heard the second largest one i am it was because it's also
turned off and this little thing fell onto the um the ground and and then they decided to not
rebuild it again but it was um and dear colleagues please i can hear you thank you please turn off
your microphone okay um and um that was where m james bond fought um the villain of um golden eye
and up here and he didn't fell fall down but that you willingly fell down cast um develops through
to the um dissolution of carbonate rock and by water and the dissolution of carbonate rock it
creates a positive feedback with hydrology meaning that if you have dissolved fractures of fissures
brings more water more water brings more acids and you have more and more um and the solution at one
place and at the end you have these like caves and landforms and that you see here on the pictures
class is not only beautiful it's also quite relevant so um ah i'm sorry yes and there are
varying definitions of cast i won't speak so much about this now but cast is also relevant um it
covers around a quarter of europe's land surface and its home of about a third of its population
breaking it down to individual countries we see that um quite a lot of countries get substantial
fractions of water from caste aquifers so this and the x-axis you see the fractions of carbon network
outcrops in different countries and on the y-axis you see the contribution of cast water to total
water supply if you look at the uk we are more or less here so i guess you most of you know that
um a lot of a substantial fraction of your drinking water is coming from
chalk um a very nice example that i always like to talk about is austria
austria gets about fifty percent of its water um from caste resources but it's not empty steeply
distributed equally it's mostly the city of vienna who's fed by cars aquifers who is um
hosting or is the home of most or a large fraction of austrian people so that's the reason why if we
find a lot of austrian um people and drinking cast water unfortunately for me germany is here
in the lower than 10 area but um that's one reason why i work internationally and not
nationally internationally or globally could say that around 10 to 25 percent of the um population
is fully or partially dependent on caste water and because of that it's important
to understand the challenges for cast water management so we would like to understand what's
going on with our resources when climate change changes the boundary conditions of our acquisition
system or land exchange changes for example the et rates um of our systems and and we would like to
understand we have to understand how this affects water availability as well as water quality
a nice example about water availability shown on these photos on the right hand side and it's
the same spot so you see the same house here and here it's a casting spring in in palestine
that was um photographed in 2004 with a spring just behind this little bridge here
discharging a small river in 2011 the spring fell completely dry or it was completely dry
this was not because of land use chains or climate change it was because of excessive
pumping of the aquifer and the regional water levels they decreased so much that actually
no water was discharging more at the casting spring and this was more or less um
at the end of 2005 when the pumping began and you see here um how the discharge changed over the
season and then how it gradually decreased and fell dry at around the end of 2008 so this was
in a very short time period when the spring went from almost natural conditions to completely dry
so to quantify the impact of farming climate change land use change on cast water resource
and quality of course a lot of approaches already exist and but these approaches were
mostly developed by local water managers or by hydrogeologists that were facing a particular
problem and and for that uh hydrogeological characterization approaches and hydrological
modeling approaches were developed for i think since um computers exist but um in recent times
um there was a emergent need for large scale quantification of groundwater resources
because for water governance because for um being prepared for future changes because of
and spotting local locations and times where groundwater um would face problems
and these um quantifications were mostly based on large gas simulation models um which are of course
at those large scales strongly simplified representations of the groundwater systems
and when we apply those models globally and there will be substantial gaps not just in understanding
but also in terms of data coverage because you know it's difficult to measure what's invisible
below us and it's even harder to do this with limited financial resources or at locations or
regions where it's just hard to work outside or to reach with your um with your drill truck this um
cross section shows a larger regional groundwater system and
from the mountains with snow line and two original aquifer system local aquifer system
and the carbon and rocks here at the sea level and you see like like it's really
they're so contrasting landscapes and that we might have to ask ourselves how well do these
large-scale simulation smalls actually work in these different regions and this brings us to
what i will talk about today because my focus as a early career researcher or maybe now i'm not
early career scientist anymore i am since october but um what i have been doing in the last
six to eight years i was looking at large-scale models uh to see how well they
perform on those regions that i'm interested interested in which are the cast regions and
beyond that i try to provide improved approaches to quantify their resources at a larger scale so
in my postdoc in bristol together with thorsten wagner and and the guys over there with francesca
and rafael who are still there and we developed the first last scale cast groundwater recharge
mode and compared to other simulation tubes that perform or that are applied at this scale
this model was quite simplistic it had only four parameters it was based by its structure
on conceptual understanding of how the caste system works i will explain in a moment and
its parameters because it was so simple and could be found by something similar to a calibration we
called it a parameter estimation by soft rules because it was not as strict as a calibration
but it was an inverse problem that we solved and as observations because groundwater recharge
is as difficult to measure as groundwater some say even it's it's even more difficult
to measure we used um proxy information which was evapotranspiration and former observations
that we got from international databases um which were fluxnet and the international soil
moisture network speaking about the conceptual structure of the model and its realism you can see
how the model structure looked like and i won't go into the in every detail but what the model um
what makes the volvo different to other models and simulation approaches at the large scale is that
this one allows for preferential or concentrated recharge by allowing simulated water fluxes to
flow laterally if infiltration rates are exceeded and and and they will end up at places where
they can infiltrate more easily and and the last flow path that is indicated here is concentrated
recharge that would be a large cast conduit or caster cave the model is applied with a 0.25
decimal degree m resolution over entire europe and what you see here is the mean annual recharge that
we calculated over a 10 year time period which mostly reflects the precipitation patterns but
like in terms of in terms of pattern but um it was the first estimation of casting recharge on anti
switches and you will soon see how this compares to the recharge estimations of non-casting models
um in one of the next slides and the particular thing about this model was also it expressed
the uncertainty by the parameter estimation um strategy and you see a pattern of like
increased uncertainty towards the south where less observations of evapotranspiration and
soil moisture were available in fact down here there was nothing available we had the highest
observation density here in middle europe as you can assume okay so with this model developed we
wanted to see how how it compares to a traditional large-scale modeling approach and to do so we took
a very um common large scale or global simulation model which was a pcr globe wb model developed
by colleagues in utrecht and and led by yoshihi devada and who was also a co-author of our study
and we compared this to the model that's just a different sketch it's the same order structure
and this is what we found on the y-axis you see the observed recharge that we got from literature
with you the each point there is a study that we found where recharge was quantified by different
methods with uncertainty of course but um it was quantified at the local scale um aquifer
scale for example so we assumed that these were more precise um than the simulations at least
and on the y-axis you see the simulations of the two models in orange the non-classic pcr
globe wb model and in blue the car is small of course we see a lot of scatter but drawing a
line through the observations we we find that on average the casting model gets it a little bit
substantially better than the non-casting model which is also logical because you see here in the
sketch of the model structure which is based on the real model and that there is no possibility
for recharge to infiltrate preferentially everything that cannot infiltrate here um that
it will flow laterally and or discharge a surface runoff and here in the classic model theoretically
surface runoff is also possible but it almost never occurs under natural conditions so what
becomes surface runoff became groundwater recharge in the cast model that's why it's um receiving
more recharge and why it's being more realistic in the casting regions we also turned off groundwater
recharge in the casting model by just assuming that here there's a homogeneous um structure
of of vertical conductivities and so we did not allow a very fast flow path and that represents
vertical cast fissure and we got quite close to the 21 parameter um pcr globe wb model is just
four per millimeters so this also gave us um some indication that um despite their various different
structures the reason for the different of difference of the two models is the cast processes
so with these two models that were somehow evaluated with this independent data went
for uh prediction in that time the cmap six small ensemble was not available yet so we
went for the cm5 model ensemble and rcp 8.5 to really see uh like a worst case scenario
and and we projected groundwater recharge into the future here the simulation domain
is split into four different regions humid regions which are the green one mountain
regions which are like slightly blue one my apologies you don't see it so well i guess
but it's the alps in here former jugus latvia and here the pyrenees so this is where the mountain
regions are located somehow here turkey and then we have the mediterranean regions which are
mediterranean area mostly and then we have dessert regions which are mostly located
in the south you see um on the time axis 20-year running averages of simulated recharge
and the great um area behind the simulations that's the temporal variability that we found
within the 20 years in addition we have a dashed line only for the cast model which is always like
here the heterogeneous heat which incidence this is the simulation uncertainty that we get from
the um from the parameter estimation procedure overall what you can see in
terms of tendency both models indicate the same there will be a decrease of recharge which is
due to an increase of evapotranspiration and the decrease of precipitation at least in some
regions what we can also see that from the humid regions to the desert regions and the variability
increases which is due to the climate variability but also the uncertainty increases from those
regions where we have most observations in the human region to the mountain and the mediterranean
in the desert region and for the desert regions and certainty of the simulation model
it becomes very interesting because you see here the cast model indicates seven percent of degrees
of recharge um and you see the dashed lines they are here and here so the uncertainty of the model
of the projections of the model is actually higher than the predicted change of recharge which means
the model doesn't say anything that we can rely on so that's what like just as the side factor
important to include uncertainty especially when working with climate change projections because
you need to have some precision to actually find some trust in your results also you see quite
obviously the model's difference it remains into the future so that would tell us that and there
is potentially more groundwater available in cast regions and when we submitted this and we cut with
your comments everybody says like does this really mean we have more water we didn't know about
and of course not um there are two reasons for that first at the local scale the properties of
cost and the high infiltration rates they are known and considered and second cast despite
its high water availability is often reduced for water supply because of its um contamination risk
and this brings us now actually to the um talk today or to the main topic of the talk today
which is in the estimation of um groundwater contamination risk and caste aquifers so um
in the second part we took the same model and tried to estimate the risk of a contaminant
reaching the subsurface very quickly which should be very high in the caste system because of these
shortcuts from the surface we took the same model and we combined it with simulations of travel time
distributions which is the approach that has been often applied at the at the local scale
and we use that um to derive the fraction of water that is younger than a certain time
so in this case we took the 90-day threshold so um the collar scheme here over you indicates how much
water is actually younger than 90 days as you see we if we go down to the mediterranean region here
we find quite substantial fractions of water that is younger than 90 days while in the
middle europe northern regions we find less and we did an evaluation with stable water isotopes
to test whether this is right using the young water fraction method developed by um jim kirk
here in scott yarziko which i won't go too much into detail you have to see the paper which is
published last year and with a data set of 119 cast spring isotopic records
and we compared the simulation of the model later after finding that there is
some trust in the simulation with the half lifetimes or survival times of different
degradable pollutants so we went from the more conservative simulation of travel times
to the simulation of overused the stimulation to estimate how much of different pollutants
is still abundant in groundwater recharge and four different times of degradation
and this is my last figure and but it's a bit more complicated so i will explain it
in a couple of steps so um you see on the y-axis the different degradation times so
going from 90 days that i showed in my last slide we go um from nine from five to ninety
days we stopped at 90 days because that was the maximum value that we could evaluate and
we estimated on the y-axis the rapid fraction of recharge so this is what has been shown on the
collar bar in the last figure here you just see it for the four different regions humid mountain
mediterranean and desert so the same locations that we had also in the recharge projections also
we compared how large the rapid recharge fraction would be if focus recharge though
the concentrated recharge is turned on or turned off turned off is the case that we used to compare
with the pcr globe wb model with the other model evaluation so this is just the same setting of
the model so just no focus recharge and you can oh so you can see quite clearly when you compare the
the dashed lines the full lines that it's a really big difference whether you have focus
recharge or not and this figure is this difference is most pronounced for the mediterranean regions
if we look at like particular um solutes and we chose salinimicin and glyphosate and e-coli
pharmaceutical and that is given to frogs parks and then with the menu it comes to the field and
gleeful said everybody knows it and e coli i think everybody knows it as well and they have
like different um degradation or survival times are given in the literature i just used some
like representative values here use 10 days for glutathione i used 25 days for the poorest in
60 days and we'd look at them and all their um pharmaceutical and agricultural contaminants at
md grade you can see for all of them and how much will remain in the groundwater recharge
if um if focus 3 charge occurs and if we look at clear phosphate we find in the mediterranean
industry that a 20 might not be and decompose when it reaches our water um storage that we
use for water supply and this is something we actually don't want to happen and so
so carsick they can produce more groundwater recharge
which would potentially be more water availability for our groundwater system groundwater drinking
water supplies but because of the shortcuts we also get a high contamination risk um and if
so sorry i didn't come to practice the last slide so because of my daughter so so
overall you can say what i just say casting shortcuts allow for rapid transport
the rapid lateral flow and transport and and these result in very high groundwater recharge volumes
but if these time scales of transport fall below the time of degradation and we showed a couple
of examples where this happens and we might get pollutants in our aquifer which we wouldn't expect
if we would assume um homogeneous conditions like the pcr globe wb motor and many other ones
this was it from my side i want to thank you again for the invitation and i want to thank
all my collaborators that were co-authors on this paper it's quite a big list because
um of the data sets we used for evaluating the model and i want to thank you for your
attention and hope and didn't overstitch my time too much thanks a lot thank you very much
for that very interesting talk and in the interest of time we'll probably probably won't take
questions now but if you have a specific question that you'd like to pick up we we do have a
a panel discussion um after this this session of talk so you could pick up any specific question
for andreas then um so i'd like to now move on to our next speaker which is um dr doris wendt
um a research associate from the university of bristol and she's going to be talking about the
management of invisible water resources so could i just ask you to stop sharing your screen andreas
thanks a lot and so doris if you're if you're great
so we can see that now doris sorry so i'll pass over to you the floor is yours now
sorry doris i think i think you're still muted because we can't i know i know and the video isn't
on i'm there yes thank you uh thank you kieran um cool all right um yeah so i am doris went
uh it still sounds funny when people say dr doris i got my phd literally a year ago um and and so
now i'm recently at the university of bristol um and still uh honorary fellow at birmingham
um so i'm going to talk about um managing the invisible research groundwater uh and this is
based on on post-op and phd research uh with birmingham uh bristol and a lot of collaborators
um and as i said um yeah and images are found on various websites i would like to highlight the
photo contest that i really enjoy um and as i said i don't have so many years of experience in
the bank yet actually yes so actually i started uh from an engineering graduate i started as a water
manager uh in in bergening and then the hydrology masters works of it as consultants um but did the
phd in english where i studied mainly in the uk and in california and similar to young gen
on managed expert recharge and now bristol as a placebo so um that's me and i'm not going to talk
i'm going to talk about my main research interest really and that's how water is one resource
and many many users so it's very viable resource this is from the uh world war today frederick
mother last year um and and that's a new series artificial which is really cool um but yeah as
a valuable resource it's used for drinking water um growing food processing food a lot of energy
and an industry think of cooling or hydropower um and there's also relaxation getting into water and
being refreshed really so it's one resource with many many uses and that means it needs careful
management particularly when it runs out so this is talking about groundwater surface water and
droughts and the impacts of drought events can be very very stressful dangerous and damaging
so unlike floods drought is like a creeping event it can start very quick there's something called
flash droughts which people might not have heard of um but it generally doesn't start
as a float and it doesn't end as it's not as well and that means it's difficult and and stressful
and possibly dangerous to to handle but also to manage so it can be as chris highlighted earlier
thank you to human health food system energy um and industry and it's very costly to like provide
the sorts of water facilities compensating industry or for example the agricultural
um sector for losses um and when it's not managed well or whether it's in a frame event and
and it can be irreversible consequences for for vulnerable wetlands shrinking weapons can spring
with your bodies um or or water quality can decorate very very fast in some areas in the
world there's also subsidence uh so thinking of your of the surface basically um which
can be a compound event of many neighborhoods so in other words there's a strategic response needed
um to droughts um and groundwater acts so this is based on my ph libra research and uh and an
illustration of your standards being drawn for the thesis um so um the in like ground is very much
the invisible rescue resource so groundwork is sourced more often during rights and you can find
various resources bits and pieces in the world an area fits in various areas in the world where
this is the case it's stored on the ground it's in this big aquifer as everybody is referring to
very cool cool and clean water source um uh not always um as as previously highlighted
but it does respond a lot slower to rain so that means if there's no rain there's a lacquer vein
your rivers might fall um before your groundwater will decline so it complements river flow
and reservoir storage and therefore the dependency on groundwater increases and this has consequences
and for this i'm going to take you to the uk which you might not have known but we do have droughts
um here in the uk and they look like this roughly really so in the northern durham river style dry
in kent this is um the south east uh reservoirs were completely low
you can see the guy with the umbrella uh standing on roughly the same position
um and then the wheelchair where there's a lot of chalk streams that went dry and so i looked
into finding patterns and ground drugs making not only a groundwork availability but looking at how
it would manage then how management impacts were affecting factoring water groundwater availability
um and what we found is that it it very much needs a strategic uh groundwater response so whether
water is used in short birth periodically or continuously and i think we can find all of
this across the uk because it's a heavily used uh water sourcing dks as andrea's highlighted
one needs to consider the balance between recharge and abstraction so not making sure
that those are in proportion for all of the users involved and that's not only what it
is that's also one of our ecosystems and and so it's important to consider um slow recovery post
drought or slow onset those right so that delay is really important to uh include um so drug
management are in place uh to manage the water resources and to protect fundamental ecosystems
and that's important also to prepare for uh extreme droughts with climate change
so this is the newest physiographic newest icc reports uh you can find this in the policy maker
summary um but i would really recommend you to go through uh the lethal chapters it's quite
impressive what they found together um but when we look at groundwater and the sections and water and
groundwater reserves um it stresses how well first of all it's already under pressure that many needs
are instead before that's competition ford is one water resource but climate change these droughts
extreme events are likely to occur more often happening already in many places you
can think of the last severe rights in europe for example um and the frequency of height waves will
reported more and more often and this also
refers to a change of rain seasons so for very much rain dependent lightbulbs irrigation
agriculture without irrigation this is this is crucial uh and so wooden shortages are very
and for this to illustrate it i would like to take you to an example that uh i've witnessed myself
this is a photo of danica desert in ethiopia um
and this girl is harvesting the ground water from the well open well
um for her luggage and thinking of where she now gets her life and how she can stand locally
with climate change people living like this are possibly going to be really really vulnerable
and so about so in ethiopia i was working further south by the irrigation at that time
and irrigation management and i happened to be there during a drag and of course you don't plan
these things it's very drastic and very imagined one on everybody living living at that place and
time and so from this big river you can see how well there was very little water there really
um people were gathering uh in these yellow tanks they're drinking water for washing as well
cars are being washed in the river cows and you can see the tanker there um so
and and providing solutions to well this is an extreme event i think this
was statistically going to happen well as one every 80 years based on past
observations um but but the question is is groundwater going to be the solution and
this is very much a hot topic this came out this week from the bds from allen mcdonald mistaken
um and and so the question is is this is groundwater going to be the golden bullet
is this going to save many countries from suffering drug resistance drugs and
and i think we need to be careful saying yes this is this is going to save the world
um because i think we need to have a plan we need to think when to fix ground and how to do that
and for this i'm going to take you to the world concepts of drought management so this is a bit
of my phd research again um not directly related to africa but more in a conceptual abstract way
um talking about what drought management actually is so first of all it will have some kind of drug
definition they'll have a monitoring system well which very much was the telephone
or some kind of automatic updates there will be a warning system in place
where the water reserves are high or low or well as you see here very long there are some kind of
water risk management plan so certain measures in place and you hope that's an evaluation
and one researching more and more about these drought management
plans um so this is based on the paper that came out in october
we can think of certain classics so when a drag hits the first classic way to cope with
it is using groundwater because the reservoir all the river flows are falling falling low
um and groundwater can be used for unlimitedly maybe time bound maybe it's mountain drug permits
maybe to maximum volume per day or in total um but but that's very much one kind of approach
uh that that we see more and more often another one would be restricted water use
so whether this is surface water which you can't use for certain maybe for irrigation
or or industry or groundwater there are limits on groundwater abstractions this can follow from
a monitoring system and as chris was saying earlier this can be related and it should
probably be related to vulnerable ecosystems so that when uh rivers fall low and ecosystems
uh are endangered to dry up that you stop irrigating because they are very much connected
so it's it's relating restrictions on what to use to ecosystems to water users
agricultural water use industrial and domestic and in this there's a very really wide range
and particularly um for for for different kinds of restrictions in water use um and i think the
most striking i've found so far this is again the world war today contest photo last year
was when people this is in syria had very very little even without and so we hope there are
suitable mental plans in place to avoid this for most of us um and there are so these are the two
plastics and these are lesser known management strategies so i was mentioning through excel
earlier today that there's water transport it's very commonly used strategy to move water from
an abundant place to place a shortage this can be very short and small scale like happening here in
in um pictured by someone in bangladesh um but it can also be a large scale so
in the uk for example water can be all the way from wales to scotland to the southern bay of
england and for example where young chin and i both did research in california and central
valley water comes all the way from the north of it uh central a lot of california to the sun
so water transport is apparent in all kind of um shapes and sizes uh another way we think would be
to think of integrating water sources so to look at flexible water use conjunctive use of surface
water and ground water using reusing water so whether that's treated non-treated um but thinking
really carefully when water is kind of done being used and whether you can close circles in your
so yeah as i said earlier young and i have a research a lot on
studies management for recharge which happens in the states on large scale smaller scale um on many
many other places either intentionally or not intentionally um and then as was mentioned this
morning in ua um the assassination of seawater is another solution so we have a whole suit
of different options suitable for various areas simple very management systems people vary users
but the key question is are we well equipped and are we prepared so what's next well i'm basically
modeling way water resource strategies in bristol with the water engineering group and wessex and if
i'm not indie gorgeous this is what people don't know this is the suspension bridge in bristol
and if i'm not cycling or climbing into gorgeous i'm probably typing and modeling away uh looking
at integrating water resources for congenital use uncertainty of models parameters and decision
making um so this directly with francesca um and the key question is are we well equipped enough
and prepared um so more science finding are going to be presented with egu um so i hope the program
doesn't change this is meant to be the slots um but yeah do get in touch or cool thank you
thank you very much doris for that really interesting talk so we've probably got
time for a quick question if anyone has one they want to maybe use the q a
box and if anyone has a quick question
someone's actually raised their hand i think so yeah so i can't see them on
oh maybe they've lowered their hand now so sorry yeah okay but perhaps in in the interest of time
just given that we're running a bit behind schedule if anyone has a has a question
specifically for direct maybe we could pick it up in in the panel discussion thanks a lot doris and
now next the next speaker is um dr laura richards from the university of manchester so laura will
be talking about the and the work she's been doing in india which i know she's she's um
she's been doing a lot of work there up there when arsenic so um over to you now laura thanks a lot
thanks karen can i just check if you can see my screen and get my sound okay yeah everything
everything's fine fantastic thank you okay um so yes hello everyone and happy world water day
um i'd like to thank the organizers for the invitation to join the workshop today it's
great to be here um so today i'd like to provide an overview of some of our groundwater research
activities which are in northern india and so we've been working in bihar over the last several
years as part of an indo-uk water quality project called farganga which is supported by nerc in the
uk and dst in india so this project is actually a consortium of eight different institutions
including the university of manchester i'm affiliated um i'd like to acknowledge the
many contributors to the aspects this work that i'll um present today um but particularly the fire
gang of pis dave polia and manchester and biswajit chakravordi at the national institute of hydrology
okay so in this presentation i will just briefly introduce the context of our groundwater research
and give an overview of some of the selected subprojects um in bihar all related to
different aspects of groundwater quality and management especially with a focus on arsenic
so a big motivator of my research um is that three in ten people globally still lack access
to safely managed drinking water services we know that water quality is central to the unsustainable
development goals um however there's major challenges which remain in meeting these targets
and with the groundwater theme of today and i'll do from the last two talks and we
know that groundwater resources are particularly important especially given the increased reliance
on groundwater due to climate change and especially in places like india where groundwater
provides drinking supplies for millions of people so one high priority groundwater quality challenge
in many parts of the world including india is arsenic so arsenic is an inorganic gluten and
is naturally occurring and elevated concentrations of arsenic in groundwater supplies that are used
for drinking impact the health of millions of people in south and southeast asia and elsewhere
because of the scale of these impacts groundwater arsenic pollution has been
described as the largest mass poisoning or sorry largest poisoning of the population in history
in aquifers in south and southeast asia and which are typically
reducing and relatively shallow there are common processes which contribute to the mobilization
of arsenic underground water from the surrounding sediments so when naturally occurring arsenic is
bound to sediment it presents a relatively low risk to people however when there are sources of
bioavailable organic carbon and metal reducing bacteria the arsenic can become mobilized via
the reductive dissolution of of arsenic varying iron and mining in these sediments there are also
other mechanisms of arsenic mobilization including pyrite oxidation and absorption
from arsenic variant minerals which can also occur under um certain certain circumstances
but once argentina has become mobilized so once it's released into groundwater
that's when it potentially can pose a major risk to people who are exposed
through drinking cocaine or even agriculture in some cases
and chronic exposure to arsenic in concentrations that exceeds um the world health guideline limit
um a provisional provisional limit of 10 micrograms per liter or even perhaps lower
concentrations as some more recent studies suggest can lead to a number of detrimental health impacts
okay so even though the dominant mechanisms of arsenic release are relatively well established
however there remain key questions regarding where in the subsurface these processes actually occur
and then importantly the source and type of organic matter that may be implicated
in driving arsenic released so this has led to substantial and long-standing debates in the
field of arts and geochemistry um regarding what the origins of high-ground arsenic really are
and the key question here which still remains is if human environment interactions and
particularly um large-scale groundwater pumping
have a role in leading to secular increases in groundwater arsenic
so our research group has been working to address this question and others related to
both how and why groundwater arsenic contamination occurs and ultimately what can be done about it
so we're interested to understand groundwater vulnerability in different contexts
and in particular and the processes which may impact the release and transport of groundwater
arsenic and other pollutants as well um we're also very interested in developing
um systematic decision support systems and guidance regarding the optimal selection
of remediation strategies to best mitigate against public health risks that are associated
with groundwater arsenic okay so with that um kind of background i'd like to showcase some examples
of the work that we've been recently doing in bihar so this first um example is a study that
came out in in 2020 related to the distribution and geochemical controls of arsenic and uranium
in groundwater used for drinking and bihar so here the aim was to systematically characterize
an organic geochemistry in groundwater used for drinking to understand how these contaminants
are spatially distributed and what the dominant processes are that are likely to impact this
and so we ran a field campaign before covet and where we drove across every district of bihar
every 39 districts um covering almost 6 000 kilometers um in collecting around 300 grand water
samples and from different depths and pre-selected random locations and there's a lot of details here
i won't go through and i'm happy to ask questions or answer questions if you have any on the details
um so here's some pictures from the fields you can see we collected symbols from both
private and government wells we took some measurements directly at the time of sampling
and other parameters we measured back in labs at the university of manchester and with other
collaborators as well so a very brief summary of findings and the major composition of the
groundwater was dominated by um sodium calcium and magnesium as cations and for anions bicone
bicarbonate and chloride and so this groundwater type is quite typical of shallow groundwater
and some of the groundwaters also indicated that some ion exchange reactions would occurred
so we were interested in characterizing the dominant groundwater chemistry because it helps
to identify the conditions and controls on trace contaminant mobility and also has implications in
terms of selecting appropriate remediation strategies which i'll touch on later so we
compared major concentrations to guideline values from the world health organization to determine
the proportion of samples exceeding guideline values for example there are around 16 of samples
containing arsenic over the guideline of 10 provisional guideline of 10 micrograms per liter
and also manganese nitrate and uranium exceeded guideline values in some cases
especially given the substantial work on arsenic um done already by the researchers in bihar
and elsewhere in india and we were interested to see how representative our sampling was
and to compare to some of the other studies out there and by targeting random sampling points in
advance we were aiming to reduce sampling bias as much as possible although in some
cases this was still impacted and by logistic issues like road and site access so we compared
our randomly sampled locations to a known arsenic hotspot in bihar and our random sampling in this
survey always found lower concentrations and were found in the known hops hot spot zone so this has
a couple of important indications and firstly that random sampling like we undertook and potentially
may miss localized influences but in contrast if only known hotspot areas are studied that could
potentially lead to a significant overestimation of overall concentrations across a wider area
so these maps show the distribution of arsenic on the top uranium on the bottom
with dots scaled to represent concentration and so arsenic concentrations were typically highest
near into the north of the gengar river especially between the gandak and koshi tributaries um
in contrast uranium was mostly elevated and abandoned along into the east of the gandak river
um and as you can see from these plots or from these maps and the distribution of both arsenic
and uranium is highly heterogeneous and which is likely due to both geological and redox controls
and the concentrations of groundwater arsenic and uranium are inversely correlated so that means
areas where there's higher arsenic typically have lower concentrations of uranium and vice versa
and based on median values at district level districts north of the ganga river generally
trended towards higher arsenic and lower uranium whereas districts south of the genga were inverse
to that so generally trended towards lower arsenic and higher uranium so the mobility of arsenic and
uranium is strongly controlled by redox conditions which explains this inverse relationship
with arsenic usually mobilized under reducing conditions and uranium under oxidizing conditions
okay so we also looked at the relationship between depths and these parameters
so in bihar as well as many other places and the depths of private or government wells
can vary substantially anywhere from five or six up to 200 meters um we found in our study
and we did see that the concentrations of arsenic were broadly dependent on depth for some sirens
outside so i hope that's not too distracting um the highest concentrations and typically occurred
in relatively shallow wells less than around 40 meters in depth as you can see here there's a peak
however elevated arsenic still did occur um
at deeper depths as well these similar trends are mirrored for both iron and manganese
and because iron is positively correlated with both iron and magnesium and adversely correlated
with eh and sulfate this is consistent with the mechanism i mentioned at the beginning
of arsenic released by the dissolution of iron and manganese based sediments
okay so to briefly summarize this first part um so we characterized the the major
in trace geochemistry and groundwater across all districts and be higher
um finding that arsenic and uranium were strongly inversely correlated and that the distribution was
highly heterogeneous and this work generated quite a lot of media interest in india in
particular because this was the first um published representative study across all districts of bihar
and also because groundwater uranium hadn't previously been systematically investigated across
the state um so shifting to quite a different type of groundwater pollutant and so this time
emerging organic contaminants or eocs so eocs can cover a very broad spectrum of compounds
including human and veterinary pharmaceuticals antibiotics chemicals used in agriculture industry
and chemicals used in the food and beverage industry like like artificial sweeteners
um so we published another paper last year um looking at at eoc's and groundwater
in the capital city um of bihar which is patna and this was a higher resolution
study focused on patna specifically as an example of a rapidly developing city in northern india
and where we were looking at um how urban to rural transitions might impact what sort of
inputs there are into groundwater i mean what kind of chemical signatures we're seeing in the
water that might be resulting from those inputs and so we we were looking at emerging organic
contaminants in this kind of broader context of groundwater vulnerability um but also because of
you know wider wider interests and eocs related to antimicrobial resistance and ecotoxicity
so the aim here was um really to kind of quantify and characterize the distribution of groundwater
eocs around the urban center and surrounding areas of patna um it might seem that organics are quite
unrelated to the first part of this on arsenic but more broadly we are interested in characterizing
surface-driven organics and groundwater and particularly under rapidly developing cities
and because of the potential implication over the implications of surface-derived organics on
arsenic mobilization in certain contexts okay so i'll skip quite quickly through the details um but
we did find a wide range of eoc's um there were around 70 compounds detected at low concentrations
um nanogram per liter to microgram pollution levels um the compounds had a really wide variety
of uses including medical and veterinary uses agrochemicals industrial and lifestyle chemicals
and interestingly artificial sweetened sweeteners which are classified as lifestyle
compounds were the esc that we found by far the highest concentrations in groundwater
and so the concentration and composition of eocs didn't vary quite widely across the study area
and generally with highest concentrations i'm located relatively near the urban sensor
and closer to the river whereas rural areas um in general were more dominated
by agriculturals which makes sense in terms of land usage in these areas
okay similar to um when we're looking at arsenic we looked at depth profiles
of here of eocs um noting that we found eocs at all depths and from zero to 120 meters but
noting the similar a similar near surface peak um so in some cases there clearly are localized
influences and this could be due to geological heterogeneity or a leaky borehole for example
but the important implication is that groundwater in rapidly developing cities such as patna
can be vulnerable to surface derived organic contamination such as from from eos
okay so we do know that modern organic carbon um or monica or modern organic matter is getting
into groundwater under patna but we are still working to investigate if there is a
linkage between um surface drives organics and arsenic in this context so and we're working
to use a suite of environmental tracers including residence time indicators and to estimate our
snake accumulation rates and to try to disentangle some of these underpinning processes particularly
in comparison to other arsenic impacted areas for example in cambodia and bangladesh
okay so for this third little mini section
and i'd like to give a very brief overview of remediation strategies as ultimately
um i'm interested in what can be done to improve drinking water quality in bihar and elsewhere
so any time um for example there's a contaminated groundwater and we're looking towards a safer
safer drinking water there's a number of different um remediation approaches or strategies which
could be undertaken including those related to um hazards exposure and receptor um
exposure related includes water treatment and things like well switching which
i would say um probably the majority of efforts um fall into into this category
okay and so in the context of arsenic specifically there are a number of technological approaches
um which have been applied in different settings and by far the most straightforward is just simply
switching to a different source for example a lower arsenic groundwater or a treated surface
water but this option might not always be available and there are a number of other
technical approaches including precipitation absorption iron exchange and membrane filtration
oxidation by our remediation in bihar and these are some of the commonly observed remediation
approaches and this is the household's reverse osmosis system and these are community scale
filtration units these are especially prevalent in areas which are not covered by centralized
supplies however um there are a number of apparent implementation barriers which exist
and in some cases this relates to technical performance and
but in other cases there are issues around access or maintenance and convenience socioeconomic
conditions awareness ownership or issues around regulation and monitoring
and so that we've observed some of these these um barriers in bihar as well as in other arsenic
impacted places that we've worked like in parts of myanmar um cambodia and vietnam as
well so especially given the um implementation barriers that are observed it's really essential
that technical aspects are considered alongside environmental socioeconomic and regulatory aspects
when considering um the selection and management of appropriate remediation approaches
and really there does not appear to be a one-size-fits-all solution that applies everywhere
so we recommend that a systematic approach to remediation selection is really needed
um which adequately considers both groundwater and stakeholder aspects in order to do so key
selection criteria should be determined and prioritized according to local requirements
um okay so during the bihar wide groundwater survey and we evaluated the performance of all
of the household and community scale groundwater remediation units that were encountered we did
find a wide range of types and scales of systems ranging from simple homemade buckets sun filters
um to multi-stage commercial filtration systems to membrane based systems um and we found that these
the performance of these systems and perhaps unsurprisingly varied very widely with removal
of arsenic and other organics ranging anywhere from zero percent to 100 under those particular
site specific conditions we also found that there are a number of remediation units which were and
which are found to be treating the arsenic waters but interestingly um source water composition um
and particularly the ratio of um of iron minus 1.8 phosphorus over arsenic was found to have a
a positive association with arsenic removal um which is which is interesting because this ratio
could then help to provide um a theoretical input relevant for remediation selection
um regarding the extent to which the groundwater composition may be geochemically compatible with
arsenic removal so this could be used to i we've done a mapping of on behalf of this um to map
out spatial patterns in geochemical compatibility and to identify where for example additional iron
might be needed to facilitate higher levels of removal so this could be used
as a decision support tool alongside other very important considerations like the managerial
socioeconomic parameters i mentioned before to help inform optimal mediation selection
underpinning um all of this is the very important um role of transparency and
effective knowledge exchange needed um to underpin effective selection and
management of remediation strategies so this is just sign posting um a resource about it
okay so um i'll bring this to a conclusion now um we have found
that inorganic contaminants such as arsenic uranium can be present in some parts of bihar
and that mobility is controlled by geochemical conditions and we've also found emerging organic
contaminants in groundwater and patna which is consistent with other studies um so they associate
that shallow groundwaters in bihar can be vulnerable to a variety of water quality impacts
in terms of remediation and there's often a gap between successful technologies and successful
implementation so an appropriate mitigation strategy must adequately consider the local
context um including geochemical socioeconomic and regulatory factors as always our work is
very much ongoing and there's much more research to be done in these areas so um
yeah it's a it's a it's a moving it's a moving machine this is just a disclaimer about some of
what has been presented um today and then lastly and most importantly i'd like to
fully acknowledge that the funders and people and institutions that have contributed to the work
um mentioned today um and the organizers again for inviting me to contribute um thanks karen
thank you very much for that really interesting talk laura an impressive
amount of field work and sampling has obviously gone into that research
so so we probably have time for it for a quick question and i think one has just popped up on
there the question and answers tab so let me just so it's from ben howard so it says thanks for your
talk laura please can you comment on how large scale surface water groundwater interactions um
we might expect these to a matrix of reducing and oxidizing conditions
that affect the mobilization of uranium and arsenic
yeah thanks ben i think that's an excellent question um i think even even in the context
of of arsenic and i know you asked about arizona can uranium but we see that like
shifting redox conditions um even due to you know groundwater table fluctuations throughout the year
can have a big role in arsenic mobilization absorption desorption processes
partial equilibrium conditions that can make it really quite complicated
um looking at you know larger scale groundwater surface water interactions i suspect it's it's
the same thing so looking at which you know which controls are the most dominant but realizing that
there's a lot of noise and probably whatever is happening and that any of these things are
probably going to be controlled by quite a complex um you know mixture of of impacts
um particularly because of the redox sensitivity of of both arsenic and uranium so yeah it's it's a
it's a great question i think there's a there's a lot that can be done to look into it further
okay that's great thanks a lot laura so in the interest of time we'll probably
move on to our to our final speaker of the session which is um adam ward who's an associate professor
at indiana university and adam's going to talk today about groundwater and what we should be
looking for in groundwater to make it more visible so i'll pass over to you now adam all right thanks
kieran and uh thanks everybody for sharing part of world water day uh with me and for the opportunity
to to muse a little bit about groundwater uh which is what i think this next 15 minutes or so will be
about um so this was mentioned in the earlier session and and of course the theme for today
um is about how we manage this seemingly invisible resource um i wanted to start there with the idea
that um there's about 40 times more groundwater on the planet than there is surface water but
clearly because it's below ground it's less obviously visible so that is sort of the
the moniker i think or or the origin of the idea of groundwater as an invisible resource
um what i'm going to argue to you today is your default position should be that all water is
ground water if you're interacting with it it's probably just temporarily spending some time
in a stream or lake in other words we should reframe our thoughts that any fresh water we're
interacting with is groundwater we just happen to catch it at an unusual time um we wouldn't
label a species nocturnal because it happened to be awake once in a while even though a majority
of it of its life cycle was occurring at night you know and and i have a similar perspective on
and so that's what i'll argue with you today is that surface water uh is a wholly inappropriate
term and we should we should start calling streams things like temporarily not below ground
and we'll look at that sort of how that's played out over the last hundred years today
so when we think about groundwater and where we can actually see it i think these are the kinds
of images that come to mind the interactions that the average human has with groundwater are almost
certainly because they're seeing it discharging at the surface this could be in the form of a spring
where you potentially put water into a plastic bottle and make millions of dollars or simply fill
your water bottle on a hike a geyser or a thermal hot spring where we sort of know and understand
that water is coming up out of the ground with different energy and chemical characteristics
and even groundwater seeps where we see evidence on the surface for example
plants that are specifically adapted to wet or saturated environments reflecting locations where
groundwater preferentially reaches the land surface so these are the obvious answers well
what what is visible about groundwater it's these few places where they intersect the land surface
and you'll see several images i'm pulling today
many of them will come from oscar meizner's work in 1923. this is actually his dissertation
and he's at least in the u.s sort of colloquially referred to as the grandfather of modern
hydrogeology and when we look at the study of groundwater we started with a group of geologists
and so it's not surprising that they brought to bear the terminology from their field
so groundwater outcrops was a was a really popular way during the 20th century to describe
things like springs as well as artesian wells and a whole host of studies were done
in which groundwater was essentially described as a function of the structural geology
and that makes sense you're bringing your traditional toolkit to bear
and in the same way that a geologic unit might have an outcrop so too might an aquifer right
the place where the water intersects the land surface well that's an outcrop
um at the same time and this is you know a hundred years ago now
we were very comfortable with the idea that the water table could intersect the land surface
in other words when we saw a stream as depicted here they're using the term depression spring
but this is a case where the water table on the phreatic surface the groundwater is
intersecting with the land surface and so more than 100 years ago we see origins of this idea
that surface water and groundwater are not separate disconnected parts of the
hydrologic cycle instead they are one in the same surface water is simply a manifestation
of where the water table writ large happens to be above the land surface at any given time
oh i'm going to focus a little bit today on intermittent streams
this is a sort of a very popular topic right now so streams that are not flowing constantly
but who are dry for some portions of the year and so this morning i went on to web of science
and searched for intermittent streams just to document you know this exponential increase in
the phrase intermittent streams in the literature we're now publishing more than 200 papers a year
on intermittent streams and citing ourselves 8 000 times in the process um and the early work
i showed you comes from again 1923 which did not make web of science apparently um
and i just wanted to highlight here this is a map of lodgepole creek this is in the northwest
or north central united states but this is a place where you've got a stream
that is alternating between being perennial meaning flowing year round and they're using
the word ephemeral here though i suspect he meant the word intermittent meaning flowing sometimes
so you know while this is a popular concept today it's it's not new here's another figure from that
same dissertation what you see on the right in sort of all of these hashed or dashed lines
is a section of the land surface and the different colors which i've added instead
of just the line types are depicting how often something flows so dashed lines are
what were described as ephemeral streams flowing only in response to storm events
in blue were perennial streams so these flowed all year and in red were intermittent streams so
streams that sometimes flowed and sometimes didn't uh and so you know we have this perspective that
these streams are representing the places and times where the water table intersects with and
is above the land surface a perennial stream is simply an indicator that the water table is always
above the land surface an intermittent stream being a place where the water table would come
and go not quite 100 years later one of my friends and mentors ken benkala in a nice publication
describes streams as the dynamic expression of local groundwater conditions and i'll take it
one step further today and and argue to you that one way of viewing streams is simply
a catastrophic failure of an aquifer in other words the only reason that surface flow exists
in many streams is because the aquifer is unable to convey groundwater now from
that perspective that puts any water above the surface as groundwater that is just temporarily
had to flow across the land surface so excuse me one way that we can conceptualize this is
thinking about a valley and all of the exchanges of water and its movement both in the surface and
the subsurface and what i'll ask you to do is stick with me in the next few slides with this
conceptual model on the right hand side the idea here is that there is a subsurface conveyance so
think of that like the colluvium that's deposited in a valley bottom and above that is a stream and
if the valley is sufficiently wide or deep or permeable that all water could be conveyed in
the subsurface it would be and in places or times where there's more water that water would upwell
to the land surface and activate a stream and so in this way we can start to simulate
down valley transport in the subsurface and the dynamic activation or turning on
and turning off of subsurface flows so i want to show you what this looks like
in a headwater catchment so this is a small second order catchment this is in the cascade range in
oregon united states it's at a long-term field site called the h.j andrews experimental forest
and so what we'll do here is apply that model to the h.j andrews to see what happens
and i'll play an animation for you and so what we've done is simulate this network
in this case for one water year so where you see gray that's an indication that it's a channel
that's not flowing and where you see the colors that's an indication of how much discharge is
flowing above the ground so what is the stream flow and so what you can see is that as we go
through the wettest portions of the year much of this channel is activated i'll point out to
you there are some places where the stream is active and then goes entirely subsurface
as we get into some storm events here through base flow recession you'll see that under high
discharges the network expands and then through recession the network contracts
until a storm causes it to expand and reactivate again so you know again from this perspective
we perhaps might want to reframe what we're thinking there's always water flowing through
this catchment it's simply manifesting sometimes as above ground and always with flow below ground
the last piece that i want to point out here
is in the summer it's extremely dry and we get these diurnal fluctuations in discharge
these are driven by daily evapotranspiration and you can see portions of the stream network that
flash on off on off during the day we have been there we've photographed it we've documented it
that's a real phenomenon that happens in this site so again this is the case where
a stream as an entity is is perhaps an odd way to think about it the stream itself is just one
one way of seeing or way of understanding what is happening to a more complicated system
so throughout the year one thing we did was take a look at these segments and ask
is the segment flowing is it not flowing and if flowing is it connected in other words could
a fish swim there from the downstream end of the catchment and so much like you saw in that diagram
um a few slides ago you can start to classify portions of the stream network as flowing
disconnected connected dry under different time periods through the year
to see just how dynamic this is what i want to show you is on the x-axis day of year
and on the y-axis distance from the outlet so the bottom left corner for example is at the outlet
of the basin on the first day of the water year and as you go up the y-axis you're going upstream
where you see white there is no flow in the stream network and where you see colors that's telling
you something about how much surface water there is so some features to point out there
are sections um up near the headwaters of the catchment that activate only during storm events
and then deactivate very quickly afterward those would have been meissner's ephemeral streams
there are places that are flowing almost year round more than half the time in the case of
of number two but are never connected to the outlet so that would have been an intermittent
portion of intermittency we see a step change in discharge at the confluence as expected
because there's significantly more tributary area downstream upstream we see significant contraction
during the driest parts of the year and rapid expansion when small storm events hit uh and i
want to show you on the next slide those diurnal fluctuations that were driven by transpiration
so we're going to zoom in on that black box that says see figure seven and when we zoom
in on that part of the year you get this this view that almost looks like corrugations in cardboard
and what you're seeing there is the diurnal expansion and contraction of the flowing network
so we estimated about about 300 meters of stream that wet and dried on a given day due to that
transpiration i want to point that out here um not because we're the first to observe it
in fact we're far from it there's a whole body of work about groundwater dependent ecosystems
going back to some great work from meibom in the 1960s and a few years later in meinzer's
1927 publication about plants as indicators of groundwater discharge and so you know well i'm
not going to talk much about vegetation as a reflection of groundwater discharge
today i want to point out that in addition to springs seeing groundwater because of its
impact on an ecosystem is another way that we have historically viewed that portion of the subsurface
okay so perhaps you're you're willing to indulge me and think about groundwater uh as sort of the
default and this dynamic realization whether it's in the form of a stream expanding and
contracting or a spring i also wanted to think a little bit about the modern ways of seeing
and so let's compare and contrast some of some tools that we're using today to those that
are um those who came before us were using
groundwater outcrops as where we started today i mentioned springs and seeps and geysers
one really interesting technology that's now being used are forward-looking infrared cameras or flear
groundwater typically being colder than surface waters in the summertime and the inverse true in
the winter using thermal cameras we can actually identify locations and estimate magnitudes of
discharge in ways that are not possible from simply viewing it with the naked eye so we're
still working on groundwater outcrops but with a much more sophisticated way to identify them
well our predecessors have used tracers so we've injected something into an aquifer and watched for
it at a different well we're increasingly using techniques like geophysical imaging to follow
that tracer in between our wells well models ranging from uh tice and the analog of groundwater
to heat flow to electrical analog models where networks of resistors and capacitors were used
to solve darcy's law to theoretical models like those of toth and maebum
we've certainly come a long way but we're still doing a similar process we're representing the key
features mechanisms processes and tensors in solving systems of equations
which is fundamentally unchanged in the last 70 years simply faster computing power
historically we would have looked at groundwater levels using a handful of wells that were
drilled in this case this is a famous prairie profile where toph did much of his early work
in a more modern setting in addition to geophysics i wanted to highlight the
the grace satellite mission where anomalies in groundwater could be detected at a global scale
by making microgravity measurements satellite-based microgravity measurements
and so we had a global picture of groundwater for the first time i really think that's an important
milestone for our field because this is the first global look at groundwater to my knowledge
and finally i wanted to also highlight education as we make groundwater visible
so this is in the 1960s where you know to become a hydrogeologist you basically tagged along with
a handful of people who identified that way and learned by doing and being in the field
the groundwater project i wanted to highlight today sort of a modern equivalent
so there are a host of really excellent resources that are available for free
for budding hydrogeologists as well as the general public to learn about groundwater
and make it more visible in our day-to-day lives okay so two things i hope you take away from today
one is that well it's easy to default to calling things surface water because that's where you see
them if we were willing to reframe our perspective and think about that as groundwater that has
temporarily been forced above ground we might have a very different picture of how the world works
and we might regulate in a more comprehensive way instead of treating these as separate entities
perhaps you'll at least if you won't go that far you'll at least agree with me that surface
waters are dynamic expressions of their local groundwater conditions and that there are
some exciting new tools and approaches that are helping make groundwater more visible
and seeing measuring understanding what is there is the first step to managing it in a sustainable
way all right thanks for your time everybody i appreciate it and i think i get to chat with
my fellow panelists uh and take any questions that you all have for any of us thank you yes
indeed so thank you adam thank you all four of you for fantastic presentations today lots of
really really interesting um reflections and i am totally with you adam on seeing um surface water
as a as an out crop or an outburst or a surface manifestation of groundwater so i like that a lot
um so we've had a couple of questions come in so that were targeted to all the panelists and
of course we need to reflect on our topic of today which was how do we make water and sustainability
issues more visible so i think we've we've addressed those broadly and just to pick up
the question that has come in so we've got very nice talks guys for all speakers so considering
what has been said during your talks i'd like to hear what you think of artificial recharge
of groundwater particularly would you consider it as an option for those areas for natural recharge
area has no longer pervious sub surfaces or even where exploitation is bigger than natural recharge
so who'd like to take that first i'm willing to stick my foot in my mouth while my fellow
panelists in a moment think about it um so um i think you know artificial recharge um
is a good potential is it potential band-aid um a potent or a plaster i should say a potential
you know it's a way to try and solve the exploitation problem without reducing our water
usage right um what what does concern me a bit is that kind of has the same ethos of the idea that
water flowing to the ocean is a waste of water and that every drop ought to be stored and managed for
human consumption and so i do get a little nervous about the downstream impacts when we
change the timing and magnitude of flows that we are so of course we're favoring human consumption
in that case over ecosystems um that may be appropriate in some cases but i i think there
are there are at least potential consequences that way that we would want to consider so i i guess
i'm i'm i have a mixed bag i'm i'm hard-pressed to watch my fellow humans not have access to
clean water right i'm also aware we've spent a few hundred years using that strategy of not letting
water flow to the ocean and rather than living within our means we continue to over exploit the
resources we have and i i fear we might be back in that cycle if we are attempting that um okay
that's the knee jerk and then maybe maybe one of my colleagues can fix the things i just said wrong
doors perhaps yeah no don't work over there i really enjoyed your talk and your queues and
groundwater that's really interesting um yeah i had a little thing and thanks for the question
um so um yeah so in so the examples that spring to mind uh for me at least are the the manage
expert recharge as it's done already 60 years in the californian central valley um and i agree with
adam that it's basically is a patch like there's a lot of irrigated water uh a lot of irrigated
agriculture there there's a huge demand so there's not so much water coming in
so they they locate water elsewhere store it into reservoirs and now also subsurface to meet that
watermark so it's one way of solving the problem to just make sure it stays that long ago but the
other way of looking at it is do we really need that amount of water which is a bigger
beyond beyond us i think a bigger question to address so yes it's possible to use this
and yes this technique works i think it's conditional to how you apply it because
in ca so in cape town where i worked with emily so the international water management institute um
there was a call for meditation for recharge after cape so after cape town in in the um in the valley
north of that close to uh close to victoria and and they used treated wastewater to do to like
infiltrate uh or like recharge the aquifer and that seems like a brilliant idea because then you
have more groundwater more storage for pretoria and all cities around it however the water wasn't
quite treated so then you have an active source of pollution intentionally going into your aquifer
and that is really really dangerous so it is really is conditional it's very much conditional
whether it's intensive uh intended managed how it's managed um i saw a talk yesterday about um
the uk like a mine shop acting as a recharge well in like old mines and wheels and you can
immediately think how the shaft of the mind is a perfect mass system with pollutions so so it's
it's very much um how is it how is it actually affecting the question and is it done properly
i just had a quick comment that i i fully agree with with doris i think it's quite
important that it's conditional in terms of water quality impacts um
it's this this is a peripheral area to my own research but i'm aware that some of the
mars systems in india are potentially vulnerable and it's highly dependent on
on the type of aquifer right that's actually there so testing and site-specific conditions is
is really quite important so um not separating the quantity issues from quality issues as well and
you don't want to solve one one problem and create another one inadvertently so yes yeah absolutely
and i think we've touched also on that point of um both legacy pollution pollutants emerging
pollutants and then of course you know the the biogenic sources of of arsenic for example so you
know obviously there there are huge considerations there and this morning we heard about for example
um microplastics we heard from andreas about glyphosate and other um organic pollutants so i
guess yeah i mean the big issue really and i guess this comes back to to adam's point in a way that
if we think the the groundwater is actually the source on the surface but the surface
water is where it actually picks up a lot of the pollutants i guess with the exception obviously of
some of the the heavy metals and things are about their geologic contaminants how do you frame that
then you know do we actually need to be thinking about cleaning of the surface water before it
goes back to the groundwater or what would be you know how how would we then frame sort of policy
recommendations and suggestions going forward of of how to to manage that holistic system again
anyone want to tackle that
well i can comment on what happens in the uk where the regulations are very very strict for manager
recharge um water that's being recharged needs to be drinking water quality so it's it's not
like it's not distilled water but it's very high quality and even here there are discussions about
whether you can very very clean wood with chloride because that's um if you can infiltrate that so
i think there's a big spectrum um in that way so that's for managed aquifer recharge but what what
about or well again i'm not a hydrologist in any way so if this is a daft question i apologize um
i guess there is natural recharge so and there one of the questions i also had was you know does that
then lead to potential risks from from stormwater runoff or from you know highly salinated you know
potential influx of seawater for example if if surface sea water levels rise and things so
um you know are those potential risks that we need to be thinking about into the future
yeah so eso i'm i'm willing to say a hundred percent yes um right so
what what is in the surface water ends up at least to some extent in the ground water
stefan showed us that a bit this morning looking at microplastics and some of jen drummond's work
on how those are potentially surface water sourced but ending up in some of the shallowest and
fastest ground water flow paths um another another application that's sort of troubling to me is
the there's been a lot of work in the last year showing that the basically tire wear compounds
so as our tires on our vehicles degrade um that those are both relatively
toxic contaminants and they also break down into other novel contaminants in the environment and
if those are in our storm water and we're using a retention basin where infiltration
is the strategy uh of what to do with our with our urban runoff what we're actually doing is creating
a point source into our groundwater uh and and sort of writing a check that is going to come
due when our next generation has to try to use that groundwater for something
and we're we're dealing with this today right as we see legacy pesticides
and high nutrient loads in our ground waters that we're trying to pump and use for other purposes um
we're we're also coping with the problems that our prior management have created so i think yeah i'm
not sure if i'm answering your question or just amusing inspired by it um but you know as as goes
our pollution on the land surface goes our ground water and the the time lag is really interesting
at least in the u.s i see that many cities would have started with surface water intakes for their
drinking water supply and then as surface water got too polluted those cities switched
to aquifers right so once i've polluted this the river too much i'll start pulling from the aquifer
it's more expensive because i have to pump it but it's cleaner
until those legacy pollutants show up and now there's too much nitrate or ddt and then perhaps
it's cheaper to go back to surface water recharge or infiltration galleries on the banks so we
we seem to be playing a game of whack-a-mole in terms of uh you know which which pollutants
are we going to deal with in which order um at least in at least in wealthier nations i think
super any thoughts or reflections from any of our other panelists laura
i guess just to a at a small comment that i mean a lot of these influences happen even without
pumping and things like that right there's natural processes that lead to the surface drawdown
so even in areas where there's not all these extra complications there's still recharge
from the surface and bringing bringing down to depth whatever is at that surface right
so i don't think that you know keeping these things completely separate is possible at all
which is adam's point entirely of his talk but in terms of you know policy as well there's a lot of
you know groundwater usage surface water you should separate you know dealt with completely
separately but you know connecting those dots a little bit more i think is probably
quite important because it does have big big influences one certainly impacts the other not
certainly a lot of you know what what a lot of the research is pointing to with with arsenic as
well you know natural contaminant but how is that maybe influenced from surface drive contaminants
even that are coming down under completely natural natural recharge processes yeah big questions yes
yeah yeah um yeah sorry i thought i think i've misunderstood your question before but um i
was thinking also of so i was thinking of the work of andreas maybe i don't know if it's on
at this moment but of the the the different travel times and how wonderful which areas are for
for natural pollutions coming from the surface to the ground water and as and as adam said rightly
so we're writing the check for the next generation we're basically um polluting the water source for
for people to come um and uh and yeah i think we should like there is more and more regulations for
like with the waterfront directive or for restricting others in europe um
uh for restricting surface pollutants but there's big questions to be answered
super so we've got a few more questions coming in on this so um from ben howard
suggestion could increasing groundwater level affect useful ecosystem functions that remove
pollutants for example higher water table leads to groundwater discharge in streams
reducing the extent of hyperx zones which are hot spots of biogeochemistry for example
anyone want to to address that adam i ben i'm willing to give you a maybe um or it depends
and i know that's not a fun answer um but it's uh you know these are really complicated systems
um and so when we it it's it's really hard to pick apart one mechanism and say well if we make this
one change for a desired effect what would be the the outcome um you can imagine a i don't know if
we've got an arsenic source that exists because of fluctuating groundwater levels going from
reducing to um aerobic environments right and we just keep the ground the water levels high
that's probably good in some ways right it might stop that mechanism or that source i'm making that
up so perhaps i could be corrected but then again you've just kept that groundwater table high and
that's going to stress out potentially trees or vegetation that have been adapted to that you're
taking away the natural signals that are triggers for fish to decide when they're going to spawn
so i'm i'm given my knee-jerk unfortunately isn't it depends because you can't it's really hard to
pick off one management question in the system and not have it have this cascading set of effects
and i think unfortunately well fortunately if you're a scientist unfortunately if you
want to do something practical there's a lot of questions where we only have kind of a first order
expectation right do x impact is y and only 10 years later do we realize that y was also
connected to z and to beta and to q um so i know that's not a satisfying answer perhaps but it's
it's i kind of think where our science is right now but maybe andreas or doris or laura wants to
wants to disagree or or come up with another example there
yeah all right i'll try um sorry thanks then that is a that's a good question and the very big one
as i acknowledge this um so that's actually sorry in eco lab you might might be aware
of this uh george larsen and bruno are looking into uh removing pollutants with wetlands and
that's the first thing that comes to mind so um sometimes there are artificial weapons and
voidlands as a kind of natural filter to generate some pollutants but but it's only
some and it only works for certain times and you know the chemistry much better than i do
so so it's really only a small bit of the answer the other the other thing i would look into if
you're interested in this is um i know that in the netherlands where it's very low-lying lands land
they have tasks to increase the groundwater level um to uh to see how that interacts
with the agricultural pollutants um so i would point you in that direction
for any useful instance but yeah very good questions i'm afraid we we can't quite answer
okay so then there was a question from layla bentley to to laura and stefan if he's still
on the call um which said i missed the discussion about desalinated water do you consider this water
to be more or less contaminated than groundwater and are the technologies to assess them similar
any solution for the arid regions such as the arabian peninsula
laura do you want to to take a first point at that yeah i'll take a first point at that um
i always find questions a little bit difficult if it's if something's more
or less contaminated because there can be a lot of different contamination types um
for example like not to keep going back to arsenic but
dangerous levels of arsenic can be very very low concentrations right at tastes that aren't you
know detectable or unseeable anything like that um the question about desalination if this is
more or less contaminated than groundwater i think again it really it really depends um technologies
to assess them if what you mean by assess is measure what's in there in the first place
you can get a rough idea about how saline water is just with a simple electrical conductivity
measurement or total dissolved solids and that's something that's quite quite easy and relatively
cheap to do with a little handhold meter if you're looking to do trace analysis of chemicals or
pathogens which you'd really need to do to have an overall kind of assessment of water quality
that's going to involve involve more um so you could for example have a very um
low low saline water low tds water that still had dangerous concentrations of pathogens or arsenic
and similarly you could have a higher tds water and arsenic pathogens fluoride might be just fine
so again i think the answer is is it entirely depends on context and i think there's kind of no
no replacement for doing site-specific testing that said there are like hazard
maps and things that can be used to give like predictive indicators of things
from your um your talk earlier you i saw that you've done some kind of in-situ measurements as
well i just wondered if you if you thought there were any potential surrogates that that may be
maybe useful for fixing up some of these other contaminants with emerging contaminants
um you're quite quiet karen i met in institute's measurements but what was the second part of that
question i said um institute i saw that you've done you've done quite a few and made quite a few
institute measurements different parameters yeah and i just wondered if you were aware of any
potential surrogates or if your initial analysis has identified whether there were any potential
surrogates for kind of the the wider suite of emerging contaminants that we were discussing
you know it's a really good question and it's something that we we've started to look into
a little bit in the data but there's nothing obvious that kind of stands out
at first look i mean the things that we commonly measure in the fields would be you know kind of
standard you know ph electrical conductivity um orp we also do in situ measurements of
nitrate nitrite ammonium iron manganese sometimes arsenic but emerging organic contaminants are
such lower levels of concentration right and there's not even necessarily a correlation between
emergent organic contaminants and total dissolved carbon for example toc or doc um
we have done field measurements of doc and have found the results to be a little bit problematic
in some in some cases i think you know there's just usual storage time and things like that as
well so i would be quite reluctant to suggest that any of the measurements that we do would actually
be suitable for eocs at that stage but i am aware there are there are researchers that are looking
for or looking into like novel sampling methods and i think in particular like
capturing on um like little cartridges i don't know the right words for it but
um little cartridges to then go extract extract those those off and better preserve um some
other contaminants so that might be you know a simpler way to do some of the mc2 sampling
um but having results real-time results right then and there i think is probably pretty far
off as far as i'm aware yeah i don't know if anyone else here wants to comment on that but
um i i would just add i guess that you know if you are you know it depends i guess on what your
as you say what the input water is and then what the intended use is so i mean if it's actually for
for human consumption then there are very strict guidance on you know tests that need to be done
to show that it um is drinking water quality whereas if it's really you know it's to remove
pollutants so that you can then re you know reuse the water and for agriculture or things
like that i would say it's probably you know maybe different levels of of quality required and good
i'm conscious of time there was one specific short question for doris that i'm just going to pick up
and then i'm going to ask each of you to give a short reflection in a second so the question
for doris was how can we improve the water challenge sustainability in sub-saharan africa
especially i guess related to the photo that you showed um of the water crisis in ethiopia
yeah i was i was not quite sure what to decide that because it's another it depends
um so so there are a couple of like so from so i so i left ethiopia like i mean 2016 and
since then a lot of things have evolved um quite good in in many ways good and bad um so so one
is that there's a lot more groundwater research going on right now and so the report i i shared
where i showed the headlines of is from the bgs and water aids and they are putting a big effort
into mapping the available value so that's that's one bit of the answer yes there is groundwater
available and yes in some cases this can really mean um that they can alternate their source of
water supply easier um well as i said before is not the golden i in my opinion is not the golden
bullet i've seen examples where they use water resources too quickly too fast and depend on 100
um and then run out of it um so so it's it's very much how much water is available how are
you going to use it because it meets the needs is it sustainable so so in in other words make like
um that that's why i stress for this plan being in place knowing when you can use it what
what is sustainable um and yeah and then there's like a series of measures like whether you're like
capturing rainwater whether you're infiltrating quickly when you are um and and so that's again
it depends um so but i think you you highlighted um in the chat as well that you have asides and
there are some options being identified so um that that's really interesting and you can touch
super so that might be a connection that you guys can follow up on okay so just in the last
couple of minutes then if each of you could
convince us as the general public or our policy makers to do one thing to change one
thing and how we currently behave in order to protect our groundwater what would what would
you recommend that either we as individuals or as policymakers should be trying to do
who wants to go
first or one message you'd like us to have taken away from today
i'll go because because mine's easy uh uh groundwater and surface water aren't
different they're the same thing and they should be regulated as one okay
stars um yeah i guess from my point of view it's um it's managing groundwork
carefully thinking of the long-term thinking of the short-term not using
it as a rescue but thinking about it in in a strategic way okay laura
yeah i think i'd add that um
systematic approaches are just really important systematic approaches that are you know informed
by evidence from the stage of testing to selecting remediation strategies to managing those you know
just systematic throughout but to make sure that the decisions made are the best decisions made
with the information available at a given time i think often that takes a lot of um
communicating between disciplines and across boundaries and effective communication is a
major challenge i think that's um can be a major barrier but coming up with ways to to bridge
that gap so that there's yeah transparent and effective knowledge exchange between stakeholders
i think is really really important to deciding how to best manage these resources in the future
good and i guess this being the year of groundwater
is also a huge step towards recognition of the importance of of groundwater
so yeah brilliant i think that takes us pretty much to the end of our activities today for world
water day 2022 so thank you very much to all of our speakers and and panelists i think it's been
really informative i've learned a lot as i always do at these events um and i'm inspired now to to
start looking for evidence of the surface water coming evidence of the groundwater bursting out
and and where i'm going to find seeps and what geezers i had heard before but seeps i hadn't
hadn't come across and looking for sources of springs from now on brilliant thank you very
much everyone it's been fantastic thank you to all our participants thank you to those of
you in the room here in birmingham and those who were present in dubai um earlier on this morning
and wishing everybody a wonderful world water day so thank you everyone and take care thanks
for having us bye happy world water day everybody happy day indeed thank you bye thank you thank you