The forests of California were once home to thriving populations of fish and other aquatic species,
but their numbers have dwindled due in large part to the construction of dams, roads and culverts.
The Forest Service has quite a developed road network on all 18 national forests in California, Region Five,
and those were built over a series of decades and pretty much had a single objective:
Get vehicular traffic across the stream, you know, from point A to point B.
When the majority of the transportation system was built on national forest lands, the main
goal was to get water underneath roads as quickly as possible.
So what happened is you ended up with a whole series of culverts that were placed, usually
without much regard to looking at the risks of impeding aquatic organism passage up above them.
These roads have blocked the passage not just of fish, but of amphibians and other aquatic species.
And then there are a whole suite of what I would call riparian-dependent animals, mammals,
mustelids (otters, mink), those kinds of creatures, that
use stream corridors as routes of travel throughout their habitat.
And those culverts pose the same sort of barrier to many of those organisms.
On the Lassen National Forest when we’ve done surveys on our road stream crossings,
we found that well over 90 percent of our culverts on this forest were considered impassable
by fish and, by default, we consider them also impassable by other aquatic species.
I’ve actually videotaped fish trying to reach their natal grounds, where they’ll
spawn and being frustrated in those attempts by a culvert under a road that is either too
high or too steep for them to swim through.
And it is difficult, challenging actually, to witness that and realize that that’s
being replicated at tens of thousands of crossings, across the West and thousands right here in Region Five.
The Forest Service is improving aquatic organism passages, or AOPs, by redesigning and replacing
old culverts, and in some cases, eliminating roads altogether.
Roads are a huge source of sediment to a lot of our aquatic systems.
So over the years we have identified a number of roads that we no longer need on the landscape.
When our transportation networks were created, the mission of the Forest Service was somewhat different.
And the transportation network was appropriate to that mission.
Now the goal is to restore as many miles of stream habitat per year as possible with our
appropriated budget and our partners.
This restoration requires the work of many different Forest Service specialists.
It took the efforts of many other people in hydrology, in fisheries, in engineering within
the Forest Service and other land management agencies to actually see this to its current scale.
These AOP’s are certainly a collaborative effort.
They’re pretty complex, a lot of engineering.
In terms of my role on these types of projects I can provide the biological information
in a given stream but I’m certainly not an engineer and I’m not a hydrologist either.
So you really need all these different players coming in and working together and able to pull these projects off.
You have to address these one at a time.
You try to prioritize, where do we get the most habitat connectivity for our restoration dollar.
We’ve been trying to prioritize in terms of which ones we’re going to get the most
bang for our buck on, essentially providing access to often times miles of aquatic habitat
upstream of a crossing, that species down below those crossings haven’t had access to for decades.
It’s very possible to eliminate these barriers.
And what we’re doing with aquatic organism passage restoration, is allowing the native
fish populations and other stream dwelling organisms,
to complete their lifecycles in the habitats on forest system lands.