[ Silence ]
Hello?
I think we’re ready to get started. Welcome, everyone, to our next
Western Geographic Science Center science seminar.
This week, we’ll be hearing from Dr. Laura Norman.
And I’m going to briefly introduce her
and then turn it over to her wonderful talk.
Laura Norman is a supervisory research physical scientist
with the USGS in Tucson, Arizona. She received her B.S. in forestry
from Oregon State University and her master’s in watershed
management and Ph.D. in watershed management
with remote sensing and spatial analysis from the University of Arizona.
Her dissertation explored urban development and
green infrastructure scenarios to reduce nonpoint source pollutants
in shared water resources of the U.S.-Mexico border.
Over the past 20 years, Dr. Norman’s work has focused on
characterizing tradeoffs between different management actions
using complex geospatial hydrological, hydraulic,
and land use and land cover models.
She has published over 47 peer-reviewed journal articles
on a wide range of topics, including environmental health, cross-border
policy, regional planning, ecosystem services, and restoration design.
Welcome, Laura, and we’re looking forward to your talk.
- Thank you. Thank you.
All right, can you hear me? Is that working? All right.
Well, hello.
The title of my talk is Ecohydrology of Aridland Water Harvesting.
And so I’m going to go through a brief introduction to what that means
before I start talking about the science.
Where we live in the Basin and Range province,
soils begin in the island mountain ranges. Weathering breaks them down into rocks
and smaller particles, and they wash out
into the flood plains, sometimes in flash floods.
And you guys might have seen on the news recently there’s some
serious problems related to the flash flooding in Arizona.
The Desert Basin gets carved out and formed by these floods and flows.
So here’s some pictures of what that erosion looks like
in and around Tucson, Arizona.
You can see the soils eroding in through the washes, and you can
see that it’s a problem for some of the trees that are
holding onto the sides of the – of the washes there.
There’s just a publication by Gellis and others
that just came out that does a nice description of that.
And I actually cited one of his older papers that talks about the
evolution and development of gullies, desert washes, and flood plains.
So here’s some pictures of the gullies that washed through,
how they get carved out by the water.
They leave behind those dry arroyos, and some of the arroyos
get larger and larger and turn into these nice kind of lush flood plains.
And from there, we see some desert wetlands.
So we call those cienegas in the area that we live in.
So here’s a picture that was taken of the Babocomari
on the right-hand side – the Babocomari Cienega.
And you can see how the grass is green, and the trees are green,
and they call the kind of ribbons of green in this area –
that’s called the Madrean Archipelago Ecoregion.
So that’s a smaller subdivision, kind of, of the Basin and Range province.
And the topography in the Madrean Archipelago Ecoregion,
or the Sky Islands, ranges from 10,000 to 1,200 feet.
So because of that great variation in topography, there’s also a
great variation in climate that influences the different plants and animals.
You can see the little islands that are outlined in the black polygons.
Those are the Sky Islands.
And they’re surrounded by the Sonoran and the Chihuahuan Desert.
You can see the Sierra Madres are coming up from the south,
and they call them little stepping stones that go up to the Rocky Mountains.
So they act as conduits for different animals that are
trying to get from south to north or north to south.
There’s a lot of different biodiversity. The biotic communities vary greatly.
In this little animation, you can see the range goes from the mixed conifer
forest all the way down to the desert scrub, and everything in between.
So it provides a lot of different habitat for a lot of different species.
Here’s a map of how many species are actually imperiled in the
Sky Islands region. You can see there’s quite a bit – 28 to 47
in the red kind of blobs that occur in the Sky Island area that we’re studying.
But also ranges down – some of those you might be familiar with.
It is the location of the only jaguar in the United States.
But a lot of other species depend on the different habitats
that are provided in the Sky Islands as well.
So some of the drivers of land use and land cover change include, of course,
the climate associated with the topography that I was talking about.
We experience heavy monsoons in the summer, and that sometimes means
there’s floods. And we also have fires like you guys have out here.
We have severe droughts, and the fires and floods kind of work with the
human influence of urbanization and groundwater pumping, agriculture,
cattle grazing, timber, mining, hunting, fishing, and trapping.
And, of course, fire suppression, so –
has also worked as a driver of land use change.
So there’s some people that have identified this area
as being at its tipping point. There’s a couple kind of pinnacle papers
and books that have been out talking about the threats to the species in the
Sky Islands, the threats to the ecosystems of the Sky Islands,
threats to the cienegas, and, of course, the Requiem for the
Santa Cruz, which is the threat to the loss of the river.
In 2014, the Good Neighbor Environmental Board identified
ecological restoration as the most important thing for the
U.S.-Mexico border and to try to go back and create a more
comprehensive approach to ecological restoration at this – at this location.
And our research was highlighted in that report to the president.
Since then, a group of us in Tucson and around Tucson have created
a small consortium of agencies to share and integrate conservation efforts
in the Madrean Sky Island in order to do landscape-level assessment
at a multiple-watershed scale and to evaluate condition
and prioritize areas and methods for restoration treatment.
We met again in 2015. And since then, we have put out
two 40-plus-page annual reports talking about collaborative research.
So this is working with the Forest Service, the BLM,
U.S. Fish and Wildlife Service, Sky Island Alliance,
Bat Conservation International, Cuenca Los Ojos,
and Borderlands Restoration, and the National Park Service, of course.
And we identified that, between the group in this study area,
we’ve invested over $4 million in two years.
And so this is a pretty big issue. There’s a lot of money being thrown at
trying to do a lot of good work, and there’s a need for science behind it.
Nationwide, there’s billions of dollars being spent restoring streams and rivers,
yet right now, nobody’s identified the best standards for what
actually works to make the best river or ecological restoration.
So we started looking at what the science behind rock detention structures
are, or erosion control structures. And some of those are pictured here –
gully plugs, check dams, and trincheras. Gabions are rocks that are wrapped
in wire and fit into the channel. And the point is to try to slow down
water and slow down sediments from coming out of the – out of the islands.
Check dams have been around for a really long time.
They were identified as early as 27 B.C.
And in the Madrean area, as early as 750 A.D.
So they were originally used for agriculture –
slow down the water and allow the plants to grow at that location.
So the FAO and also the USDA has identified check dams and
gabions as working all over the country,
especially in the Rocky Mountains, to stabilize gullies.
Another practice somewhat different
than that is the Rosgen-style structures.
And these are a little bit more artistic trying to armor or do pole planting.
And in our neck of the woods, there’s a group – Zeedyk and Clothier
have identified some zuni bowls and one-rock dams –
different rock structures to slow water down.
And they really don’t think that check dams or gabions are a good idea.
And then, of course, there’s – beavers have been creating
beaver dams around our area. So different styles.
Some people don’t like the beavers. Some people do.
So we’ve been just kind of looking at, not which one is best, but rather what are
the impacts of the different structures and how we might best monitor them.
In the state of Arizona, putting structures in the water
is against the law if you’re going to be retaining water.
And so some of that – the laws around first in time, first in right,
have become an issue for people that are trying to do restoration.
And so looking at, what are the different laws.
Is it prior appropriation, or is the – are the dams retaining or detaining water?
Also, the U.S. Army Corps of Engineers and EPA have laws – the 404 permits
that need to be gotten before any structures can get put in.
And so there’s a lot of policy implications
that we are addressing as well.
But there has been a lot of work looking at the different structures
in India and also in Italy and some of the other countries.
But what we are interested is trying to figure out is, can these rock detention
structures be used to increase water availability in the Sky Islands?
So there’s your background to my study area.
Our project objectives are to determine metrics to discern
the effectiveness of rock detention structures for our partners.
And in doing that, we broke the study into looking at the impacts on water,
the impacts on soils, and the impacts on vegetation.
And working with our partners to try to identify the ecosystem services
associated with rock detention structures for flood prevention,
vegetation and habitat, healing, groundwater recharge, reducing erosion,
nonpoint source pollution, increasing water availability,
and just armoring or protecting landscapes.
Here’s a picture of the rock detention structures.
And the first one is the spreader, or the one-rock dam.
The second one is the loose rock check dams, or gully plugs.
And last, the gabions. And this was done –
these sketches were done by a student that was working us, Chloe Fandel.
The study of ecohydrology is a subdiscipline of hydrology that
focuses on ecological processes occurring within the hydrological cycle.
So the water budget – everything that comes in must,
you know, come back out.
So we’re looking at all of the different processes associated with that.
And the general assumption is to reverse degradation and achieve
sustainable water and ecosystems in anthropogenically modified basins.
So the different methods that we are using to do that are,
first of all, looking at processing remotely sensed imagery
to monitor changes in vegetation health and geomorphology.
A lot of you guys are experts in remote sensing.
But we’re using two different – both passive and active sensors to look at
measuring the natural energy and also sending out signals to come back.
And I’ll talk about those. We’ve got repeat photography.
So here’s a picture of a gabion from 2001 through 2011,
and these were taken by our partners at Cuenca Los Ojos.
And looking at how vegetation and sediment respond to the
structure being installed in the channel there.
We’re also using the Landsat imagery – the longest-running satellite program –
to look at the vegetation changes. And so looking at healthy vegetation
versus stressed vegetation using the NDVI formula in satellite imagery.
And this is a diagram showing our experimental design at the
Cuenca Los Ojos and national wildlife refuge
in the San Bernardino Cienega and the U.S.-Mexico border.
The green – or, I guess I’ll start on the left.
On the left-hand side are – we mapped all the gabion structures
that had been put in in the ’90s, and we used satellite imagery to
monitor where those structures – through time, from 1984 to 2011.
And then we also selected in the – on the right-hand side,
the green spots are the circles that are represented on the left.
And then the red spots are our control sites – so upstream
and downstream and around the streams,
where there actually weren’t any structures, to look at
the difference between treated and control vegetation over time.
And our results show that the average treated sites
remained healthy vegetation-wise –
in fact, sometimes increased their vegetation health over time.
And the areas that were our control sites decreased in their health over time.
And the decreasing trend kind of matched up with the precipitation,
or drought, trend that was also being identified in the area at the time.
And so the structures were able to maintain
or increase vegetation despite the drought in that area.
In this slide, the green – or the X’s show where the structures are.
The green spots, as they get bigger and bigger,
show where it got more and more healthy vegetation-wise.
The brown spots show where it got less healthy vegetation-wise.
And you can see that most of the spots that have gabions, or X’s, are green.
And most of the spots that don’t are brown.
So you also see, down below our study area, there’s one spot
that doesn’t have an X that’s pretty green and very large.
And for that reason, we decided to investigate what the impacts
downstream from the structures were. Because there was some question about
whether or not structures were absorbing water from downstream water rights.
So we added an index – the NDII – so the normalized difference infrared index.
And we expanded our study in space and in time to include the 2016 data set
and looked at major zones of restoration. And this is being led by Natalie Wilson,
who has recently joined the USGS on this project.
And we found that the further analysis confirms the potential of the structures
to increase vegetation up to 5 kilometers downstream from the structures.
So that’s a really big piece of news for policy holders.
It’s increasing the water availability downstream, not decreasing it.
We’re using the small unmanned aircraft systems – sUAS.
This is a picture from the front page of the Tucson newspaper with our – one of
our pilots, Lance Brady, from – he’s now with the BLM, but USGS then.
And John Vogel was working to do some image collection.
This is a picture at the Cienega Ranch of Geoff DeBenedetto flying the drone.
And you can see what it looks like on the ground –
the tanks at Cienega Ranch – and what it looks like from the sUAS.
So now we’ve got this very high-resolution data set to be
working with with our partners at the Fish and Wildlife Service.
We also are using terrestrial Lidar data sets.
So here’s some friends out in the field collecting
some before-and-after Lidar data sets in one of the channels.
And this is what it looks like from the field
and what it looks like after they did the processing.
So now we’ve got this nice, very high-resolution sub-centimeter data
set describing where the sediments are being collected or being scoured from.
And when you look at that from above ground – the bare earth DEM.
Here’s the Hillshade. And then looking at
before and after, the red areas show where there was erosion occurring,
and the blue and green show where there’s deposition occurring.
So now we’re looking at the geomorphology in the streams.
We’re actually using this really neat tool Joe Wheaton has
developed to do DEM differencing now. And we’re looking at the differences
between the befores and after and where sediment is going to
and where is it coming from.
And now we can get some numbers and put some
volume numbers – metrics with our data, so identifying that the structures can
decrease sedimentation downstream, increase water quality downstream.
One of the neat things from this publication was using the raw data set
versus the thresholded data set, which is pretty popular in the
terrestrial Lidar world, and finding that the raw data set
was really useful for riparian restoration and is published in this journal.
Okay, so we also have been instrumenting sites to document the
hydrologic and vegetative responses from structures.
And we’ve been working with James Callegary at the USGS.
And Chloe Fandel I mentioned – the artist,
a student that did her master’s thesis.
And of course, Natalie Wilson, who has been doing the vegetation analysis.
So Chloe’s thesis was instrumenting this gabion with wildlife cameras,
buried temperature loggers, and pressure transducers.
And there she is out in the field, and she did a really great job.
Put all these structures in and drew the pictures afterwards so that we could
represent what was happening and what we had expected to happen.
And she designed this housing to put her temperature sensors in.
And the pictures were really very useful as well.
Here’s a picture of what the Babocomari gabion number 2
looks like most of the time and then what it looked during flow,
which is not what we had expected it to look like during flow.
So the wildlife cameras were really useful in this case.
But throughout her thesis, one of the things – the major finding
that we’re using now in our research is an average
of 10% increase in soil moisture around structures.
We’ve also developed – as I mentioned, Natalie’s been hired to work at –
and look at the botany and looking at the vegetation growth around structures and
wondering, you know, whether or not that is impacting the hydrologic cycle.
And so she’s been developing different methodology to track
the structures and growth around them through time
using long-term plots and also using short-term plots.
So she’s going into her field season now and spending
the next couple weeks going out with her backpack and her –
and her instruments to look at the frequency and cover.
And then, you know, of course going back in time,
and she’s got her rebar there.
But some of the preliminary results – you know, she is finding that vegetation
is occurring where it hadn’t occurred before at and within structures.
And there’s some species introduction associated with that, and we’re going to
be tying that into the satellite image analysis that I talked about earlier.
We also went out to look at the hydrologic response
of streams restored with check dams.
This is a paired watershed study in the Chiricahua Mountains.
There’s the Rock Creek Watershed at the top and the
Turkey Pen Watershed below it. It’s a smaller watershed.
But in the Turkey Pen Watershed, we went out and GPS-ed
almost 2,000 check dams. There’s probably a lot more than that.
We stopped GPS-ing and assumed that they were
in every single channel and on every single hillside.
But you can see what the check dams in that area look like.
And the other watershed has zero check dams.
So using a technology that was developed by the
Arizona Water Science Center, we went out and put the
continuous slope area gauges into the streams to measure discharge.
And that was working with partners at the National Park Service
and at the Arizona Water Science Center to put – to develop a mechanism
to put the pressure transducers in and go through time and see
how much water was actually passing over those pressure transducers.
And we were able to identify during one monsoon that the
control site that had no structures in it was much flashier.
And the treated site was not as responsive to storms.
There is one peak on the Turkey Pen that you see
is pretty high for a hydrograph.
But there was a very localized storm right over that pressure
transducer during that day. So otherwise, it was very sedate.
We also found that, through time, there was more water in the treated site.
So at the beginning, in July, there was kind of less water at the treated site.
And through time, even though it had stopped raining
in September and October, there was water coming down.
And so we were able to deduce that 28% more flow
would come through at the check dam site over time.
So extending seasonal flows and increasing volumes.
We have also been out analyzing the soil samples behind the check dams.
And this kind of started when one of the guys from the Forest Service
said that they call carbon the “vitamin C of the forest.”
And so we went out to see if the check dams were actually
increasing organic matter behind the check dams versus next to them.
So we went out and took stable isotope samples and brought them back to the
lab at the University of Arizona and looked at the carbon and nitrogen ratios.
And we were able to find that they did sequester carbon and nitrogen.
And watersheds treated by structures prior to fires
demonstrated increased stored carbon relative to the other soils.
And so that is something that’s coming out in a publication
with James Callegary from the Water Science Center.
And last, but most exciting, we’re also using hydrologic models
to predict and extrapolate the changes in water budgets around the structures.
I’m a watershed modeler, so I think this is very fun stuff.
And so this is kind of a watershed model that you’re looking at,
and it’s just showing how water goes onto a watershed
and flows down – over-land flow, infiltration.
And looking at that in a model kind of gives you an idea of what’s happening.
So I kind of like to think about models like a secondhand version.
So if you go to, you know, a party, then the next day, I say,
oh, this is what happened. And somebody else says,
that’s not what happened. This is what happened.
And kind of everybody has their own version of what happened.
Well, models provide a version of what’s happening in the watershed.
And it’s not exactly right, but it’s a really good way to, you know,
kind of think about what’s there when you’re not able to attend the party.
So the first model that I’m going to talk about we used
at Nogales, Sonora, Mexico, to look at flood control.
And in Nogales, Sonora, there’s a lot of flooding.
You can see – and this picture, this was a really dramatic flood –
6 feet of standing water in Nogales, Sonora.
And it was actually a really dramatic flood for the U.S. side as well.
On the left-hand side of the picture is about a foot of water.
And that caused tons of damage, and there was a state emergency,
and there was lots of money thrown to handle the emergency
in the state of Arizona – never mind what happened in Sonora, Mexico.
There was a lot of deaths. People lose their lives and their
livelihoods and there’s soil lost and watershed capacity for re-vegetation.
So you can see that the water is pretty brown. There’s a lot of sediment and
other particulates in the water that are – put the human health at risk.
So we used the KINEROS model, which is developed by the USDA.
It’s event-based, so you throw a flood at it,
and it tells you what happens downstream.
It describes the processes of interception, infiltration, surface runoff, and erosion.
And it’s a distributed model.
It’s for smaller watersheds – sediment transport, erosion, and hydrology.
And this is the Nogales – Ambos Nogales Watershed
modeled using KINEROS.
And the U.S.-Mexico border goes right across the middle of that watershed.
The north side would be the United States, and south is Mexico.
And you can see the higher areas of runoff.
So looking at erosion or sediment or runoff risk
is what this model was being used for at the time.
We then talked with the city, and there was some embankment dams,
or gabions, being suggested by the city.
And so we decided to model the impacts of those structures to see if
the locations that were identified would be a useful spot to put them in.
And this research was funded by the International Boundary
and Water Commission, or the IBWC, that monitors
all of the surface runoff between the two countries.
So the model is able to describe in 3D the total volume and basin depth
of the water being ponded behind the structures.
And this is what the structure was as built.
This is – this is the – south of Nogales, Sonora.
There is two different watersheds that are
highlighted at Questa Blanca and Capulines.
And I’m going to talk about Questa Blanca first.
And you can see that the red line shows the hydrograph without a dam,
and the blue line shows the hydrograph with the dam.
So the dam reduces the peak flow by more than half in a 10-year event.
In a 25-year event, it’s still reducing flow – not quite as much,
dramatically, but still reducing flow. When you get to the 100-year,
six-hour event, the dams aren’t reducing the peak flow quite as much.
In Capulines, even in the smallest event,
we found that the dams weren’t making a very big difference
in the peak flow downstream, no matter what event we modeled.
However, in both the different situations, despite one not being
great for peak flow, both were holding back a lot of sediment.
And so that’s a – you know, one of the greater findings from this study is,
at the time, we weren’t really concerned with the sediment impacts and were
able to find that, even though they weren’t holding back the peak flows,
there was a lot of sediment being captured, which is, you know,
something that we had recommended that they clean out
behind the structures if they wanted to maintain their use in the future.
As I mentioned, there’s a lot of money that’s being spent on
flash floods in the area, and Nogales is the Arizona Department
of Emergency Management’s number-one priority for flooding.
And so we’ve been working, you know, to try to create an emergency
flood forecasting and scenario analysis using the model and working with the
U.S. NORCOM – Northern Command. They funded Floyd Gray from
the geologic division to put out some precipitation gauges in Norgales, Sonora,
that we’re now using to pipe into the KINEROS model live to look at what
storm events might create the flooding scenarios that they don’t want to happen.
So our results document decrease in peak flows for small to medium flood
events and a decrease in sedimentation and water quality increases downstream.
At the Deep Dirt Farm Institute, they’re looking at doing some
gully rehabilitation. And we used the
KINEROS model there, again, to look at the relative results,
looking at areas where there was higher runoff, or higher erosion.
Looking at the hydrographs resulting in those different flood plains.
And we were able to create some number estimates of
how much sediment might be coming to the check dams in the case of a
peak flow event and what a peak flow event might be at those structures.
So they’re able to use those numbers in their building of the structures.
So the structures benefit from modeling before the installation occurs.
Another model is the SWAT model – Soil and Water Assessment Tool.
This has also been developed by the USDA.
And it’s used for larger watersheds and creates measures of
hydrologic budgets, sediment yield,
nutrient, pesticide, and crop yields as well, which I don’t use for my models.
But their geospatial inputs there – you put the temperature and precipitation in
with any available soil, topographic or land use data sets that you can get.
And this is a daily time-step model. And so we’re looking at
cumulative effects over time. The SWAT model routes things
through the channels, and so it – you can pick up and move things
along and move things along. It’s just different for larger watersheds.
We were looking at the Babocomari River, which is a
tributary of the San Pedro River, and working with our colleagues
from Borderlands Restoration and funded by the Walton
Family Foundation to look at the restoration technology
of gabions to see if you could increase recharge there.
This is where Chloe Fandel’s thesis grew out of this project.
But originally, we were using the SWAT model to strategize about
where to place the structures that would be most beneficial in the Babocomari.
And so creating iterations of the hydrological model,
using the satellite imagery, their expert opinion, and then
going back and seeing which one was the best and how we might
marry them and couple them to create the best outcomes.
So we’ve got the model qualitative results.
The runoff – you can see the different – again, medium, high, low – different –
the graduated levels of sediment yield where the biggest producers might be.
And also looking at, in this case, the infiltration.
So this is mainly based on the soils data that we had available,
looking at the best places to try to recharge the aquifer.
So this is what the hydrograph looks like
halfway down at the upper Babocomari River.
You can see that the model is greatly overpredicting flow in the area.
The purple line shows the actual flow, and the model is in blue.
And so, in most cases, when I run the SWAT model in this area,
I take out the lateral flow component of the model.
So arid lands aren’t really great at absorbing water and passing it
underneath the soils because it’s so dry and there’s such a big disconnect.
So when I take the lateral flow out, I’ve calibrated the model now
for the upper Babocomari, and I’m working on using
some of the results from Chloe Fandel’s research to look at the impacts of how
gabions are impacting those flows – infiltration – 10% added on.
But at the beginning, we were using the quantitative results
from the uncalibrated model to create estimates of
how big the structures should be in Vaughn Canyon at the Babocomari.
We’re also using the model at the Rock Creek and Turkey Pen site,
so that paired watershed study that I introduced earlier.
We used the SWAT model to look at exactly how much sediment was
being captured behind the structures. And so we used the discharge
measurements from the modified CSA in order to calibrate the model and
then took it from there to generate estimates of sediment deposition.
One of the interesting findings from that study was that,
out of all the precipitation, there was only actually 20 events
over the three-year study period that generated any soil erosion
or movement in the watershed. So that was a interesting finding.
But we were able to identify about 630 tons of sediment
that was stored behind the check dams over that three-year simulation.
And, of course, generate one of these maps that shows those areas
in the watershed that were more conducive to erosion in the upper
watersheds and in the steeper locations where soils might be more erodible.
SWAT is useful for coming up with the water budgets, and we’ve been
using that on a monthly basis in our findings and basically finding that this is
a very useful model for looking at erosion control structures.
Another one that I’ll talk about really briefly was developed by some of our
colleagues in the USGS in the Golden, Colorado – in the sediment lab.
It’s called the iRIC – the International River Interface Cooperative.
And the model that – or, the solver that I was using in that is the Nays2DH model,
which is fully unsteady and does 2D simulations.
It’s really fun. You can do particle tracking,
and I find it’ll be more and more useful as we’re going along.
But here’s some results where we ran the Nays2DH using the Lidar data
from 2013 versus 2015 and were able to simulate the breach
in the gabion that occurred. And so that’s very useful for
restoration is to identify which locations might be more conducive to breach.
And we were able to model the changes and increased depth of water,
decreased velocity through time, using the Lidar data sets.
I also looked at the bedform shift and geomorphology simulations
that the Nays2DH model could do and found matching patterns of erosion
and deposition from the model to the raw Lidar DEMs of difference.
So I think that has a lot of possibilities for future simulations.
So the model – the Nays2HD decreased peak flows,
increased surface water availability,
decreased sedimentation, and benefits from modeling before installation occurs.
So that’s the summation of the results from all of our findings.
I just wanted to step through them and show you how we found,
you know, different ways of finding them.
But ideally, you know, trying to measure the success
of a rock detention structure has taken many, many forms.
And we’re still trying to figure out what’s the best for different partners.
But in the interim, our findings are being leveraged for funding
and permitting by federal, state, and private agencies locally.
And also, so they can develop restoration projects
and hopefully changing some of the water policy
that’s hindering the structures from getting put in right now.
One example is working with the Bureau of Reclamation.
This project we’re partners on in the SIRC – the Sky Island
Restoration Collaboration – with Deborah Tosline,
who is leading the project out of Phoenix, who just went out and
put a bunch of monitoring devices based on our research that the
structures are not retaining, but, yes, stabilizing.
And so there’s more research to be done there.
Working with the Forest Service and Sky Island Alliance
and Borderlands Restoration, we use the models to identify
locations in the Chiricahua Mountains upstream from Leslie Canyon
on the Bar Boot Ranch to look at locations that would be good for
putting structures in, and they use that data for their NEPA.
We’re also using the model now to create NEPA for the Tonto
and San Carlos Apache Reservation using the same model.
And there’s also been some talk about doing some international policy change.
So in June, we met with our Mexican and U.S. colleagues at Nogales,
and they want to make a new Minute for the IBWC to strategize
a framework for stormwater control in Nogales Watershed.
So this kind of – this is nice.
So in conclusion, the rock detention structures are generating some of
the same ecohydrologic response that the beaver dams historically
have been recognized for – increasing soil moisture and
raising local water tables, extending seasonal flows, decreasing flooding.
And, in fact, when I run the model around the dams,
I’m finding that I can add back that lateral flow after a couple years.
So if I run the model 20, 30 years in advance, I put the lateral flow
back into the watershed, which is really big news for arid lands.
If the model is able to actually tell us the story of what would happen
in the future if so many structures were put into the landscape,
then you’d see those kind of weeping hillsides that are occurring
where structures are put in, and more water would become
available for multiple uses. And so that’s pretty exciting.
You know, so everybody thinks of the beaver as a keystone species.
And so maybe, if humans, you know, replicate that same – that same
structure-building technology, then we can have the same kind of impact on the
ecosystem around us, so the vegetation and the animals might come too.
I’ve been working with Dr. Jan Schipper at ASU,
who has put out, over the past three years, cameras around the structures to
see if the animals are responding to the – to the water availability.
And there’s been some really nice responses.
You can see that little bear swimming in the middle, and the turkeys and the
deer come. And so, at the areas where there aren’t structures, they’re not.
And so it might – it might actually work that way,
but we are still in the throes of doing that.
We’re also interested, of course, in the impact on humans.
And so I’m working with a intern at Borderlands Restoration –
Oliver Lysaght – sent out a survey that we were hoping to put into
the SolVES USGS program to look at how people value restoration and the
watershed and how we might make that more attractive for people.
And, of course, you know, our research is going into looking at
the impacts on ecosystem functions. For instance, we had a flood associated
with Hurricane Odile a while back, and we’re looking at that and
how structures might have allowed for some water to go by.
But if the structures hadn’t been there, it would have been a complete reset.
We were able to minimize the rainfall event that brought it
down to a much less impact on the flood event.
And we’re also looking at the resilience associated with fire
and drought and bark beetles.
And so looking at our watershed study area, you can see the more severe burns
outside of our watershed study area where there were so many structures.
And so we’re interested to look at how the structures
might have impacted the resilience of the forest there.
Thank you.
[ Applause ]
- If people have questions for Laura, please use the microphone
so that those out in the – in TV land can hear.
- Hi, Laura. I had a question. So the flood control dams – one was
successful, one was not successful. Why was the one not successful?
- It just wasn’t maybe situated in the right location
to reduce the downstream peak flows.
So, you know, since then, I’ve seen a lot of series of dams
that have been more effective at reducing those peak flows downstream.
So maybe moving it or adding more dams to that location.
But it was still successful at sediment retention.
- Have you guys received any feedback about putting in
too many of these structures? That, you know, the next –
the next folks down in line to get the water are losing out on their rights?
- Yes. Yeah, that’s a big issue. And one of the reasons why
Natalie’s vegetation study is so important,
to show that the downstream water users are getting an
increase in water availability. But that is a big issue.
- So the field surveys show that there are some non-natives coming in
at a couple of the sites. And what do you think was the cause of that?
You think it was coming from outside during the installation?
And is that an issue that you have to worry about in the future?
- Yeah. That was something we were surprised to see.
But they were bringing the rock in from another area, and we were
assuming that there were some seeds being transported with the rock.
So maybe some on-site materials might have been more useful.
- Has there been any comparison between the successfulness
of beaver dams versus the structures that are in place?
And if so, could beavers be introduced to do the work?
- Yeah. That’s such a great question. There have been – MacFarland
and others, working with Wheaton, have recently been looking at
this difference and comparisons. But I’m very interested in
looking locally what the difference is and comparisons are.
And in one of our study areas, there was some beavers re-introduced
in the San Pedro River that made their way up to our Babocomari project.
And so looking at the impacts of the beavers has been
pretty enlightening and why I brought them into the study because of that.
But yeah, definitely re-introducing seems to be cost-effective.
- Any other questions? Let’s give Laura a big hand.
- Yay. Thank you.
[ Applause ]
[ Silence ]