This year, three of our interns (Oliver Ly, William West & Laura Nolier) volunteered to map the wet and dry sections of the Babacomari River - the main tributary to the San Pedro River within the Sierra Vista Subwatershed. Alongside Willie Sommers, Lucy Hyatt, Angela Garcia, Pierre Jouin and Kathy Collins, they walked through riparian grasslands and along Cottonwood-Willow Riparian Galleries, marking the presence of water using a GPS to identify the quantity of baseflow present in the river at the driest time of the year.
About the Initiative
Many people in the arid Southwest care about the fate of perennial streams and their associated riparian communities. The loss of flows in streams and rivers has social, economic, and ecological consequences, so managers and concerned citizens seek ways to track their status.
Every year on the third Saturday in June, The Nature Conservancy invites people to walk or ride horses along desert streams and map where the streams have surface flow and where they are dry. With more than a decade’s worth of data, this work is helping scientists and managers better understand and manage our riparian and aquatic habitats. The data have been consistently collected at the end of the dry summer months, right before the monsoon rains typically begin.
Wet/dry mapping has been used to:
The Nature Conservancy has conducted wet/dry mapping for more than a decade on the San Pedro River and its tributary streams. Data from the first twelve years of wet/dry mapping in the San Pedro Riparian National Conservation Area (SPRNCA) reveal that wetted length varies from year to year, but the river hasn’t significantly changed overall. That’s good news, and suggests that conservation efforts by public and private stakeholders have made a difference.
Wet/dry mapping turns a walk through the cottonwood forest into meaningful science. Participants in the past have included ranchers, realtors, regulatory agencies, environmentalists, City Councilmen, children, and reporters. It gives interested citizens a chance to learn more about their rivers and get their feet wet in the ecosystem. Along the way, mapping volunteers have encountered species such as coatimundi, mountain lion, leopard frogs, bear, Gila monsters, bobcats, gray hawks, and longfin dace.
By Oliver Lysaght
More than 1,000 people live, work, and play in the Sonoita Creek Watershed, all with varying opinions, values and preferences regarding the environment around them. In order to better understand this social landscape and its relationship to its near environs, in May 2017 BRLI disseminated a survey to watershed residents eliciting information on a range of topics including: attitudes towards, and participation in, activities in the Sonoita Creek Watershed; values residents associate with the area; and preferences for watershed management.
This survey is one research venture of several currently being undertaken under the rubric of the Borderlands Restoration Leadership Institute’s ‘Patagonia’s Water Future’ project. Aquifer recharge modeling, stream-flow analysis and groundwater monitoring are also being undertaken concurrently. Its insights can help us better understand how ecological restoration and a restoration economy might support the ecological and economic values of residents in, and visitors to, the Sonoita Creek Watershed.
Preliminary results were presented on June 3rd at Science on the Sonoita Plains:
BY ARIELLE ZIONTS FOR NOGALES INTERNATIONAL
Extract: A pristine portion of Sonoita Creek that was discovered last fall is providing local environmentalists with inspiration as they work to restore eroded sections of the stream.
From where the creek intersects with the northeast side of Patagonia Lake to a small waterfall a little more than a half-mile upstream, the waterway is fast moving and highly eroded. But members of the organization Friends of Sonoita Creek (FOSC) and Peter Stacey, a professor at the University of New Mexico specializing in streams in the southwest, discovered that above the waterfall – technically referred to as a “head cut,” meaning an abrupt vertical drop caused by erosion – the water slowly meanders through multiple branches level with the ground.
Stacey explained in a phone conversation that in his 20 years of field work across the southwest he’s only seen a handful of streams – including this portion of Sonoita Creek – “functioning the way it used to ... before humans had an impact on it.”
“It’s extremely rare,” he said. “It’s an example of what all of us are shooting for when we do restoration work.”
On Tuesday morning, the Patagonia-based FOSC led a group of people to observe the differences above and below the head cut. The excursion also included a demonstration of stream monitoring techniques and discussion of efforts to preserve the pristine section of the creek, reverse existing erosion and prevent further damage to ensure that the stream continues as a source of groundwater.
Kathy West, a 61-year-old retiree from Patagonia, described the lower portion of the creek as a “muddy mess.” Above the head cut, she said, “It was a little bit wilder up here and the stream was wider and it was very, very scenic.”
“It’s what it should be,” West said, noting that she could see bugs and flowers growing near the upper portion of the stream. (...)
An animation project by Chloe Fandel about water harvesting in stream channels.
How has the landscape in the dry grasslands of Arizona changed over time? How have humans affected the stream channels?
In this region, most groundwater is recharged through the sediment at the bottom of stream channels. So how might changes in the channel affect the rates of infiltration (floodwater at the surface soaking into the ground) and recharge (the infiltrated water traveling down to the water table and being stored)?
This video is based on background research for Chloe Fandel's MS Thesis:
"The Effect of Gabion Construction on Infiltration in Ephemeral Streams". The full thesis can be accessed here: http://search.proquest.com/openview/9...
Low-tech rock structures called gabions are commonly used in dryland stream channels to reduce erosion, slow floodwaters, and increase infiltration. Gabions may also increase water availability for riparian vegetation, and increase the duration of surface flow in ephemeral stream channels. However, their effects on infiltration and recharge are not well-understood. This study tested low-cost methods for easily quantifying the total infiltration induced by gabion construction in an ephemeral stream channel, over the course of a single flow event. We used well-established methods to find point infiltration fluxes from subsurface temperature time-series. Unique to this study, we then upscaled these measurements to the gabion’s entire area of influence using time-lapse photo data, which recorded the onset of flow and the duration of ponding. For a flow lasting ~5 hours, we ran 225 model scenarios, estimating that a single gabion could have increased the total infiltrated volume in the channel reach between it and the next gabion by as much as 255% or as little as 0%, but the most likely scenario is a 10.8% increase. We found the photo data to be invaluable in obtaining these estimates, and in understanding the dynamics of a remote field site. Future work would benefit from more precise measurements of point infiltration fluxes and better records of ponded surface area over time. If these improvements are made and our estimates can be replicated reliably, they would suggest that gabions are a more powerful restoration and management tool than previously understood.
More information at the USGS Aridland Water Harvesting Study:
As the old adage goes - ‘the more we know about the past, the better we’ll be prepared for the future’.
It was an honor and pleasure to hear a morning of recollections about water history in the Sonoita Creek Watershed with Patagonia's community members. We learned of the lush environment that sustained the Sonorasaurus thompsoni, a 49 ft long and 27 ft tall dinosaur that lived in our neighboring watershed in the middle of the Cretaceous period. We explored living memories with attendants who shared stories of bucolic picnics on the banks of the Sonoita Creek and wild west standoffs in the 1930s over blowing up the local bridge to prevent rising waters from flooding the town.
The Borderlands Institute, together with Friends of Sonoita Creek and the Flood and Flow Committee had the opportunity to introduce the science, models and planning processes which are being developed to better inform decision-making in our home watershed. Responses from the audience regarding which topics they view as important will direct future research of the institute, ensuring what we do is useful to the people who work, live and play in our beloved borderlands region.
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