- [Narrator] The Chiricahua mountains are land of history,
wilderness and wonder in Southeastern Arizona.
But like many places, these mountains have been subject
to intense pressure from westward expansion,
climate change, and unsustainable land use practices.
However, there is one watershed in the Chiricahuas
that is deviating from this trend
and showing evidence of remarkable restoration potential,
a place where natural infrastructure
and dryland streams are supporting adaptation to
and protection from
climate related disturbances and stressors.
This is Turkey Creek.
Situated on the El Coronado Ranch
and it is an Oasis in the Chiricahuas,
maintaining water where it had been lost over time,
using nature based solutions.
Managed by Josiah Austin and Valer Austin Clark
from 1982 to 2022,
its story has intrigued scientists for decades for decades.
- I remember the first time that I came here
was in February, 2013 with a large group of people.
And we came through and we were all amazed
at the land management that the Austins had done here
where they had created these ponds
and swimming pools and bathtubs
all up and down the forest lanes
where they were harvesting water.
And I could only think that the feeling that I got
looking at these structures was completely indescribable
because it was so powerful
the amount of earth that was being moved
and the amount of water that was being harvested.
And it was also indescribable
related to my professional career
because there was no metrics
and there was no scientific quantification
that described the mechanisms
that were happening in the hydrology here.
And that made me really excited
about creating an experimental laboratory.
- [Narrator] The extraordinary thing about this watershed
is the sheer number of rock detention structures
the Austin's installed.
(loud thump) Dr. Norman and her team
were able to capture GPS data on over 2000 structures.
And remarkably, that may be only a fraction of the total.
- So my husband started building small rock dams
to harvest the water and to control erosion.
And where he did that,
we noticed that the grasses came in
and they stayed green during the dry season.
And when I say a few dams, he built several 1000.
(tranquil ambient music) - We were very Lucky
where we started putting these loose rock structures
here at El Coronado.
You know, I put in one or two to protect a road,
after we put it in that area,
I noticed that the grass was greener on both sides of this.
It was almost like a retention wall.
And I thought, well, if it works here,
you know, let's put in a few more of them.
So I put in a few more and I got instant results.
You know, after 20 years,
we have 20,000 of these loose rock structures.
If somebody had come to me and said, you know, Joe Austin,
what you need to do is put in 20,000 loose rock structures,
I would say, you're crazy.
- [Narrator] There is no other watershed
in the United States
that boast this sheer number of structures,
making it the perfect location
to conduct studies on their impacts.
And by comparing the data collected
from an adjacent watershed, Rock Creek,
where there are no check dams installed,
the USGS was able to establish a paired watershed experiment
to draw and compare quantifiable insights
about how the water behaves and how the land responds
in the presence and absence of rock detention structures.
- Using existing weather gauges to monitor rainfall
or the input of water into the watersheds,
the USGS established modified continuous slope area gauges
in both streams to capture high resolution data
on how high the water rose
and how fast it receded after a rain event.
Continuously recording pressure transducers,
crest stage gauges and direct measurements of stream flow
were used to develop stage discharge relationships,
while GPS surveys, terrestrial LIDAR
and three dimensional models refined their knowledge
of water yield and sediment loads over time.
Additionally soils were sampled
to analyze their organic material using isotope analysis.
- Now I'm standing in the Turkey pen subwatershed.
This is one of the tributaries of the Turkey Creek
that we were just looking at.
And this is one
of the areas that the Austins had invested
a lot of effort into slowing the water down.
You can see here, these are small rock check dams
that they've put into this watershed.
The water here is running pretty slowly.
If you look down,
you can see it's also very clear, so they're not very tall,
but they stretch across the width of the channel.
We don't see much incision here
and very little exposed bedrock.
- Okay, now we're standing over in Rock Creek.
This is the watershed
that's just adjacent to the Turkey pen watershed.
You can see the water flowing here
is flowing a little bit faster, and it is flowing over rock.
There's a lot of exposed bedrock here.
The water flows through deep channels with large boulders
and it flows much more rapidly and with higher turbidity.
This is our control site in the paired watershed experiment
that we did at El Coronado Ranch.
- [Narrator] The results were in
and the data confirmed Dr. Norman's suspicions
of the benefits of rock detention structures.
The first result of the hydrologic discharge analysis
showed the watershed had treated
with rock detention structures,
having a 50% reduced average rate of flow,
mainly during flash flood events.
In addition, the check dams were found
to be extending the timing of summer base flows
in the treated watershed by three to four weeks.
The result that was maybe the most shocking
was that there was 28% more water flowing downstream
in the treated watershed
when compared to the controlled watershed of Rock Creek.
This goes against conventionally held beliefs
that bare bedrock transports more water downstream.
What the evidence portrays instead
is that these rock detention structures
are allowing more water to be kept in the system.
Dr. Norman's team hypothesized that the check dams
were creating perched water tables above bedrock.
A calibrated soil and water model was applied
to estimate the total soil stored
by check dams throughout the watershed.
And it found that they stored
a little more than 200 tons per year.
This erosion control around the check dams
keeps the sediment out of the stream
and increases downstream water quality.
The results of the soil isotope analysis
depicted the potential rate of carbon capture
for rock detention structures
at between 200 and 250 metric tons per hectare,
which is equivalent to what is stored in coastal wetlands.
- All of these rock detention structures
are detaining the water, they're capturing the soil,
they're capturing what's proven to be very rich,
nutrient rich soil, they're sequestering carbon
and they're allowing the water to stand still
in these dirt sponges long enough
so that the vegetation is able to take hold.
And then the vegetation then acts on the same cycle,
helping to delay the water and keep the sediment in place.
- [Narrator] The USGS teams
scientific approach to gathering data
was able to verify the eco-hydrologic benefits
provided by restoring the landscape
with rock detention structures.
The data showed that these structures
bring much needed water back into ecosystems,
store carbon and sediment on par with coastal wetlands,
support riparian habitat, reduce erosion,
sediment yield and flow intensity,
and keep water in dry land streams longer than watersheds
not treated with rock detention structures.
This installation of
and research on rock detention structures
in the turkey pen watershed introduces low-tech
and low-cost climate mitigation and adaptation strategies,
paving the way for us to use natural infrastructure
as a nature based solution
here in the Chiricahua mountains and beyond.
If you are interested in learning more, you can find links
to the papers published from this research
and other resources mentioned throughout the video
in the video's description section.