By Kimberly Mann Bruch
Part of the ancestral home of the Northern Paiute people, Nevada's Walker Basin has provided a source of water for the area's booming agricultural industry for many years. However, to support agriculture needs, water is diverted from the Walker River to irrigate crops in California and Nevada - instead of flowing naturally into the basin's natural desert terminal lake, Walker Lake. Due to the lake's declining water levels from agricultural diversions, Total Dissolved Solids (TDS) have increased so much that the lake can no longer support its native fish and wildlife populations such as the Lahontan cutthroat trout, which is now nonexistent in the lake.
What exactly are TDS and why is this concerning? Specifically, TDS are inorganic salts and small organic matter - typically consisting of minerals, salts, metals, cations or anions like calcium, magnesium, sodium, potassium, chloride and sulfate. When there is a high level of TDS, aquatic species cannot thrive; for instance, high levels of dissolved salt causes severe dehydration and can cause a species to die.
To assist in monitoring Walker Lake TDS and overall streamflow conditions in the Walker River Basin, the U.S. Geological Survey (USGS) Nevada Water Science Center, in cooperation with the Walker Basin Conservancy, the National Fish and Wildlife Foundation, the Walker River Irrigation District, and the Walker River Paiute Tribe, recently developed an innovative real-time mapping tool to inform agricultural and ecological restoration stakeholders.
To build the Walker Basin Hydro Mapper, data from USGS monitoring stations were integrated into a central web page for visualization.
"The goal of the Walker Basin Hydro Mapper is to aid resource management and conservation interests by providing a public tool for tracking dynamic hydrologic conditions throughout the basin," said Gwen Davies, Hydrologist with the USGS Nevada Water Science Center. "The interactive and easy-to-use web platform is a dashboard containing real-time streamflow data, waterbody storage, water quality, and weather conditions. In one-click, users can visualize a variety of data to better understand current and historic hydrologic conditions in the Walker River Basin. The Walker Basin Hydro Mapper tracks the delivery of program water (water that has been acquired for restoration purposes) to Walker Lake and the current progress towards the Walker Lake TDS restoration goal. The Walker Basin Hydro Mapper allows stakeholders from a variety of backgrounds to understand the movement of surface water through a complex river basin."
More recently, USGS water quality data collection at Walker Lake has expanded to include more frequent monitoring trips and real-time lake temperature profiles. This data is incorporated into the Walker Basin Hydro Mapper through a number of interactive data visualizations. Continuous temperature profiles, collected at two water quality buoys at the north and center regions of Walker Lake, provide real-time data on lake stratification and the potential cooling effect of increased surface water inflow to Walker Lake. Additionally, monthly water quality profiles of parameters including specific conductance, dissolved oxygen, chlorophyll-a, and blue-green algae can be plotted by sampling event and location. The interactive plots allow users to understand how water quality changes on a seasonal and annual basis at Walker Lake, and track potential changes related to restoration efforts.
“The Hydro Mapper is an essential part of our efforts to restore Walker Lake,” said Carlie Henneman, Water Program Director with the Walker Basin Conservancy. “We acquire water rights from willing sellers, protect them instream and deliver water to Walker Lake. The Walker Basin Hydro Mapper provides real-time tracking so we can ensure our water is in the river and going to Walker Lake as expected. The Conservancy is committed to increasing transparency on water usage throughout the Basin, and this tool demonstrates to the public how our water moves through the system.”
Real-time streamflow and stage/capacity data are collected at select sites by on-site automated recording equipment. Measurements are recorded at fixed intervals of 15- to 60-minutes and transmitted to the USGS every hour through the Geostationary Operational Environmental Satellite (GOES) system. Most current data are classified as "provisional" data since the accuracy of the measurement is unverified and subject to revision. Quality-assured data classified as "approved" is available from the USGS Water Data for the Nation.
Storage capacity is calculated using the elevation-surface area method. Surface area is calculated at selected elevations at incremental steps for each lake/reservoir determined from either a bathymetric survey or a topographic map. The incremental storage capacity is computed for each elevation step and the incremental storage volumes are then accumulated to obtain the stage-capacity relations for each lake.
“The Walker Basin Hydro Mapper is a societally impactful application of data science that makes use of USGS’ vast, publicly available data,” said Ashley Atkins, West Big Data Innovation Hub Director. “It serves as an example that communities around the West Hub region facing similar challenges can look to and learn from.”
About the Walker Basin Conservancy:
In 2015, Walker Basin Conservancy was established as a nonprofit to administer the Walker Basin Restoration Program. As of summer 2021, the Walker Basin Conservancy has acquired approximately 53 percent of the water necessary to restore Walker Lake to the primary restoration goal of 12,000 mg/L TDS. The Conservancy is responsible for the stewardship of over 15,000 acres of land that was primarily used for agricultural purposes. Stewardship activities balance agricultural interests, cultural activities, wildlife habitat, and recreational use, while providing for landscape stabilization.
About West Big Data Innovation Hub:
The West Big Data Innovation Hub is one of four regional hubs funded by the National Science Foundation (NSF) to build and strengthen strategic partnerships across industry, academia, nonprofits, and government. The West Hub community aims to catalyze and scale data science for societal needs – connecting research, education, and practice in thematic areas such as natural resources and hazards, metro data science, health, and data-enabled discovery and learning. Coordinated by UC Berkeley’s Division of Computing, Data Science, and Society, the San Diego Supercomputer Center, and the University of Washington, the West Hub region includes contributors and data enthusiasts from Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming, and a global network of partners.