Walker Basin Project

Research Projects Phase III: 2013-2016

Research Project Descriptions

Using the Walker River Basin Decision Support Tool to Perform Impact Assessments of Water Right Acquisitions, System Efficiency Scenarios, and River Health

Douglas P. Boyle (UNR) – Project Lead Investigator
Scott Bassett (UNR) – Co-Project Investigator
Chris Garner (UNR) – Co-Project Investigator
Kumud Acharya (DRI) – Co-Project Investigator
Donald Sada (DRI) – Co-Project Investigator
Tim Minor (DRI) – Co-Project Investigator
Greg Pohll (DRI) – Co-Project Investigator
Enrique Triana (MWH Global) – MODSIM Support

Previous Work:

Decision Support Tool
In Phases I and II of this project, we developed, tested, and implemented a computer-based Decision Support Tool (DST) in support of potential water right acquisitions in the Walker River Basin.  The Walker River Basin DST represents a major step forward in understanding the complex hydrologic relationships within the real system and allows users to track water from the headwaters, where streamflow originates, through the complicated deliveries and returns in the heavily irrigated Smith and Mason Valleys to the USGS surface water station at Wabuska. The latest version of the DST (version 2.0) captures the spatial and temporal complexity of important relationships among climate, crop demand, river flows, groundwater-surface water exchange along the river and delivery ditches, irrigation practices, groundwater pumping, and all known existing water rights (e.g., decree, storage, flood, and groundwater pumping) in both Mason and Smith Valleys. Another important accomplishment in Phase II was the development of a web-based GIS spatial database that is used to store all model variables (input, state, and output), parameters, and other model related information. This database has varying levels of secure access allowing the DST team to interact and share different model related information and data with other research scientists, stakeholders, and the general public on a number of different operating platforms. This database was recently migrated to servers in the Nevada State Climate Office (NSCO) where the same GIS spatial database approach is used to store and serve weather and climate information throughout Nevada to satisfy the legislative requirements of the NSCO.

Proposed New Work:

DST Overview
Throughout the first two phases of this project, the DST has been applied in scenarios that are strictly focused on assessing the impacts of potential water right acquisitions (and the associated change in place of use) on the efficiency of water deliveries throughout the system.  These efforts have been in close collaboration with a broad group of stakeholders that comprise the Walker River Water Group (WRWG) and, recently, were determined by the Nevada State Engineer’s Office (NSEO) to be essential to informing a current water right change of use application in Mason Valley.  These collaborative activities have been a significant portion of our workload in Phase II and we propose to continue these activities in Phase III.

Many of the features and capabilities of the existing DST make it very attractive for use in studies related to broader (e.g., agricultural, economic, and ecologic) impact assessments of water transactions (both permanent and temporary) under possible future climate change and/or other system changes (e.g., land use, alternative crop types, irrigation and ditch efficiency improvements, etc.) and restoration activities associated with both the upland and riparian areas.  There are, however, limitations and/or challenges associated with the DST 2.0 that need to be addressed to move forward with these studies.  The primary weakness of the DST in these applications is its reliance on the historic observations of irrigation ditch diversions to create the demand necessary to “drive” the model forward in time.  Another related issue is the lack of logic in the DST to simulate the storage and flood operations and diversions (i.e., current scenario simulations are constrained by historic reservoir operations and flood deliveries).  In Phase III, we propose to make modifications to the DST that include the ability to simulate the storage and flood operations and allow the ditch diversions for all types of surface water (i.e., storage, flood, and decree) to be simulated by crop demand and water right priorities at the ditch scale.  With these new modifications/improvements we propose to utilize the new DST (version 3.0) to investigate a much broader range of scenarios that include water transactions involving different combinations of water rights (e.g., storage, flood, decree, groundwater pumping, etc.) with an expanded range of impact assessment studies (e.g., agricultural, economic, and ecologic) using a more formal scenario assessment framework (please see unfunded proposed scenario project titled “A Scenario Assessment Framework for the Walker River Basin”).

Restoration of Native Plant Communities Following Agricultural Conversion: Effects of Seed Source and Planting Methods on Restoration

University of Nevada, Reno, Department of Natural Resources and Environmental Science
W. Miller (UNR) – Project Coordinator and Lead Investigator
E. Leger (UNR) – Co-Project Lead Investigator; UNR/NAES
University of Nevada, Reno, Nevada Cooperative Extension
J. Davison (UNR) - Co-Project Lead Investigator

Proposed work:

It is possible that increased success in agricultural field restoration could be achieved if seed sources for these restoration projects are derived from local source plants. We propose to collect seeds of native grasses, and shrubs from within the Walker Basin and test the establishment of these sources alongside commercially-available sources. We will use supplemental watering, as in our previous experiment in order to establish seeding, but propose to compare the relative success of the addition of 6 inches of supplemental water application in the spring vs. 9 inches of supplemental water application in the fall and spring (3 inches delivered in the fall, 6 inches in the spring) during the first and second growing seasons; no water will be applied in year 3 Furthermore, we plan to seed, rather than transplant, shrubs into our experiment, which we will do with three different experimental treatments: direct seeding along with grasses in year one, direct seeding of only shrubs, and seeding into established grasses in year two, which will allow for the use of broad-leaf herbicides to control any weeds during the first year of planting.

Secondly, in more intact lowland areas, we will experiment with the arrangement of woody vegetation in shrub/tree islands, in order to maximize survival, minimize erosion, and maximize wildlife use. To do this, we will manipulate within-patch species composition, patch size, and patch density using a factorial experimental design. Over three years, we will monitor impacts of different treatments on establishment success, erosion, plant diversity and cover, and wildlife use.

The effect of important soil characteristics and parameters as they relate to the establishment of restoration vegetative cover will also be assessed. Soil samples from potential sites as sources of native seed stock would allow us to develop a "soil/seed stock resource map" consisting of a variety of soil types and properties associated with a particular seed stock. Once the Phase III restoration sites have been identified a soil assessment will be conducted there as well. We should then be able to match at least some of those study site characteristics with those from our base resource map. This will allow us to utilize native restoration seed stock from areas of similar soil characteristics. Following the selection of the restoration study sites and seed stock treatments, quantitative baseline soil conditions and changes in response to irrigation and seeding treatment will be determined.

Evaluating and Developing a Habitat Based Model for Trout that includes Temperature, Flow, and Food Production

S.E. Null (Utah State University) - Lead Investigator
D. Sada (DRI) – Co-Project Lead Investigator
K. Acharya (DRI) – Co-Project Lead Investigator
S. Chandra (UNR)—Co-Project Lead Investigator

Overview of Previous Work

Aquatic life in the Walker Basin occupies a gradient of environmental conditions where headwaters are cold and relatively uninfluenced by human activities. Generally, habitat quality degrades and the influence of human activities increases in the downstream direction, with the poorest conditions in lower reaches of the river and Walker Lake. The lake dried prehistorically and its long-term biological integrity of fishes and benthic invertebrates was reliant on colonization from river populations, likely from either headwaters or middle reaches of the river. Today, much of the lower Walker River is classified as ‘Impaired’ by the Nevada Division of Environmental Protection because of nutrients, sediment, chemicals, elevated stream temperatures, and low flow conditions. The fish community bears little resemblance to historical assemblages, and the river no longer provides a refuge for species to recolonize Walker Lake.
Clearly, a healthy river is needed to support a healthy lake ecosystem, and tools are needed to assess the efficacy of different management scenarios on river and lake health with anticipated future changes, including restoration, water management changes, water acquisition, climate warming, and nutrient input alternatives.

Proposed New Work

Water temperature and dissolved oxygen monitoring and modeling (Null and Chandra)

The biological integrity of the Walker Basin depends on maintaining an integrated river system that varies within healthy ecological limits despite human water demands and land use changes.  To date, stream temperature modeling efforts have been limited by lack of measured data (streamflow, water temperature and meteorological data have been collected in different years, making acquiring necessary model input data a challenge). Stream temperatures have been modeled for one year and thermal imagery has been captured for spring and autumn 2012.  Predicting how water rights acquisitions will affect water quality, as well as sensitivity of water quality to flow and climate changes must be better understood to assess habitat for native trout species.  This Phase has three components to improve water quality monitoring and modeling in the Walker River: 

  1. Expand water temperature monitoring to headwaters and canals.  In the Truckee and Carson Rivers, canals provide habitat during low flow conditions for trout and other cold water species (NDOW unpublished data, Chandra unpublished data). Temperature loggers and handheld temperature probes will be used to identify thermal refugia and assess thermal micro-habitat in locations where modeling, thermal imaging, or the presence of trout suggest cold water exists.  We hypothesize that shallow canals may heat and cool faster than the main stem river, sometimes providing cold water habitat during summer evenings and autumn weeks when air temperatures are relatively cooler than water temperatures. 
  2. Continue refining the RMS Walker River water temperature model and evaluate proposed water rights purchases and alternative land use, climate, and population futures  using monthly flow estimates from the MODFLOW and DTS models (if available).  If alternative futures flow estimates are unavailable, sensitivity analysis will be completed on flow, air temperature, and precipitation input data to anticipate future changes. 
  3. Model dissolved oxygen (DO) using the existing water temperature model (this function has been turned off in previous Phases).  Low dissolved oxygen is a known water quality impairment in the Walker River (U.S. Fish and Wildlife Service 2003), but to date has not been studied.  Dissolved oxygen varies with stream temperatures, such that as stream temperature increases, dissolved oxygen decreases (cold water holds more oxygen than warm water).  This, in turn, affects aquatic species’ distribution and productivity.  Groundwater seeps, which may provide thermal refugia for trout and other native species in the Walker River, are typically low in dissolved oxygen and thus must be well understood before assuming these areas provide suitable habitat for cold water ecosystems. 

This Phase will improve understanding of available thermal habitat for trout species by coordinating the RMS model with the DTS and MODFLOW models through shared data and assumptions.  It will enable water managers and decision-makers to explicitly consider water quality and fish habitat changes in the Walker River from water rights purchase decisions. 

Integrate food availability and production available to trout to determine suitable temperature regimes (Sada and Acharya)

Phases I and II focused on quantitative description of relationships between the Walker River environment and its aquatic life, and determined valid ecological parameters to integrate with DST outputs. Prior to this, meager information was available to assess relationships between aquatic life and the river environment because no studies have examined these relationships in mid-elevation Great Basin stream systems. Hence, there was little ecological information that could be used to evaluate river health. Since food production for trout is critical for ongoing persistence, we have focused on establishing relationships between stream food production and temperature, which is generally governed by flow but also riparian shading and specific habitat characteristics.

Work proposed for Phase III will provide a mechanism to integrate benthic invertebrate ecological information into a temperature/discharge model and maximize its utility to assess the ecological consequences of water acquisitions and water management. This will be accomplished during a three-step process involving: 1) completion of secondary productivity data collection and quantification that was started by Sada and Acharya during Phase II studies. A few additional sample collections will be made to fill data gaps (due to high flow in June and July 2011). 2) All of the data will then be integrated into temperature/discharge relationships that were quantified during Phase II studies; this integration will create a model that integrates relationships between basic characteristics of the river environment and its ecology. (3) These relationships can then be assessed through temperature/discharge modeling outputs to provide insight into the ecological effects of different water management and water acquisition scenarios (Figure 2).

Evaluate Effects of Water Right Re-Allocation on Instream Habitat for Trout (Chandra, Sada, Acharya, Null)

An additional goal is to directly link various modeling and data collection efforts that have taken place in previous Phases.  Ecological studies during Phases I and II of the Walker River Project found that aquatic communities are strongly influenced by discharge, water temperature, and nutrients.  Research during Phase II also included monitoring flow, water temperature, macroinvertebrates, and food webs during wet years, as well as modeling studies to predict flow and water temperature at ungaged locations.  However, findings have not yet been integrated in a substantive way.

We will evaluate the Walker River as a case study for reallocating water rights from agriculture to environmental uses, with a focus on instream habitat, fisheries, and fish production.  This will explicitly include environmental criteria such as fish habitat, food availability, and primary production in water management decision-making, such as purchasing water rights for instream uses. Compiling and evaluating data from the first Phases of this project will ensure that findings are communicated with the larger science and decision-making audience, and linkages and interactions between different Phases and components of this system are identified and analyzed.  While this work compliments U.S. Fish and Wildlife Service programs by incorporating existing data and providing new finely-scaled temporal and spatial resolution ecological information to assess the efficacy of restoration programs, the additional efforts outlined here are required to integrate this information and modeling from the DST (if available) with instream habitat, fisheries, and fish production.  This synthesis of existing and ongoing research is imperative to highlight how water rights transfers affect instream habitat, and how they might impact trout and other desired aquatic communities. This modeling will also provide a mechanism to integrate relationships between water temperature and secondary production for trout that is being quantified by Drs. Acharya and Sada with water quality and habitat modeling being completed by Drs. Null and Chandra.

NFWF Phase III Statement of Work Spatial Analysis, Mapping and Database Support

T. Minor (DRI/DEES) – Project Lead Investigator


The following is a description of DRI’s proposed effort to support specific spatial analysis, mapping, and database development tasks for the National Fish and Wildlife Foundation (NFWF) and UNR’s DST development efforts in Phase III of the Walker Basin Restoration Program.  An associated budget is provided in an attached table.  The Statement of Work (SOW) and budget cover the performance period January 1, 2013 to December 31, 2015, and assumes two years for research and analysis, with a third year for finalizing the project report and responding to any review comments. 

Task Descriptions

Task 1 – Water Transaction Mapping

DRI personnel will continue to develop water transaction maps for NFWF at their request.  Map sets (in triplicate), will consist of a reference map, groundwater map, and surface water map.  Reference maps will contain PLSS data to the quarter/quarter level, parcels, and high resolution aerial photography.  Groundwater maps will include groundwater POUs and PODs.  Surface water maps will include ditches, drains, and fields serviced by specific diversions.  All features will be annotated.  Maps will be produced in PDF format.

Task 2 – Exhibit Map Development

DRI will develop, as requested by NFWF, exhibit maps showing areas of proposed surface and groundwater transfers in Mason and Smith valleys as well as the East Walker River corridor.  Information displayed on these maps will include PLSS data to the quarter/quarter section, parcel boundaries and parcel numbers, and surface and ground water rights.  Irrigated acreages will be calculated for existing and proposed water rights.

Task 3 – Ditch/Diversion Reconciliation

DRI will assist NFWF and their subcontractors with ditch/diversion reconciliation analysis.  This effort involves the analysis of diversions and irrigated fields to calculate both the total acreage of individual parcels serviced by a particular diversion and the total acreage of irrigated fields within each of those parcels.  These data will be compared to available Walker River Irrigation District (WRID) water card information to reconcile differences in water righted acreages at the parcel level, as well as water right amounts related to priority dates.  This information will also be passed on to the UNR DST modelers to assist in their model development efforts.

Task 4 – Geodatabase/Data Portal Development

DRI will continue development of a geodatabase framework for linking spatial and tabular data from NFWF’s existing ShareSite.  Spatial data layers will include PLSS data, parcel boundaries and numbers, surface water rights, groundwater POUs and PODs, and high resolution aerial photography.  Tabular data to be integrated from the ShareSite will include, but will not be limited to:  WRID water card information, including, decree, storage and priority date information; WRPT documents, acquisition documents, ditch company information, change application information, and water transaction lists.  To provide NFWF and their subcontractors with the capability to view the spatial data and hyperlink or HTML link to the documents on the ShareSite, DRI proposes the development of an Arc Server based data portal with designated permission levels for constrained access and download capabilities.  This graphical user interface will allow NFWF and their subcontractors to effectively tie spatial features of interest, such as individual parcels, points of diversion, and places of use, to the water right and other legal documents associated with these spatial entities.  DRI proposes developing the portal on a server purchased by NFWF that would be resident at DRI for the development period until transferred back to NFWF at the end of Phase III.

Task 5 – General Water Acquisition Display Maps

DRI will develop, as requested by NFWF, large scale basin-wide maps of Smith and Mason valleys showing the proximity of NFWF owned properties, closed deals, and optioned properties to existing administrative and hydrologic features such as the Mason Valley Wildlife Management Area, Walker River Paiute Tribal lands, WRID boundary, ditches, river pumps, drains, Walker River reaches, and the agricultural fields aggregated scaled up to the Hydrologic Response Unit (HRU) level (diversion assignments).  These maps will be produced at D or E size.

Task 6 – Walker Basin Restoration Program Data Archiving

In Phase I of the Walker Basin Project, DRI created an archive of spatial and tabular data used in the various research projects, and also developed a data sharing protocol for dissemination of this information.  In Phase III, DRI proposes to build on the current archive with relevant digital information from Phase II and Phase III UNR/DRI efforts, including existing reports and data.  This work will be performed based on the resources available, research priorities dictated by NFWF, and the level of effort as it is identified by project PI’s as Phase III progresses over the next three years.  The first six months of the project will be spent defining the scope and depth of the archiving task, as this effort will require coordination with research entities at UNR who have done similar database development/archiving of Walker Basin data, such as Peter Weisberg’s group in the Department of Natural Resources and Environmental Sciences, and Doug Boyle’s DST modeling group.  It remains unclear how these other entities will be funded for their contributions to the archiving task, or their response to data requests as part of the archiving and data dissemination effort.

Project Coordination, Communication and Administration

Michael Collopy (UNR)- Co-Project Lead Investigator
Jim Thomas (DRI)- Co-Project Lead Investigator
Winnie Dowling (UNR)- Budget Administration

Project Summary

This project provides administrative oversight, programmatic coordination, and support for scientist outreach and coordination activities for the overall project.  All DRI budgets will be included as a sub-agreement within this task.

Primary Objectives

  1. Co-PIs for this project will provide support for all projects. The PIs responsibilities include:
  2. Assure effective communication between DRI and UNR, and with the National Fish and Wildlife Foundation.
  3. Interface with project PIs so that as projects progress information will be shared with other University of Nevada System Desert Terminal Lake participants such as Senator Reid’s staff, Stakeholder groups, the U.S. Fish and Wildlife Service, the U.S. Bureau of Reclamation; and the National Fish and Wildlife Foundation. 
  4. Coordination between researchers and appropriate existing databases to ensure project information is appropriately and permanently archived.
  5. Assure that the program stays on schedule and help resolve significant internal issues that may arise.
  6. Coordinate all science and modeling aspects of the project, making sure that that all projects are working collaboratively so that the research from the different projects meet other projects’ needs.
  7. Ensure that quarterly progress meetings and annual reports are completed on time, and that the overall project is completed on time and within budget.
  8. At the completion of Phase III, facilitate the completion of the final report and host a Walker Basin Research Conference in Reno, NV, where results of all projects supported through the Desert Terminal Lakes legislation have the opportunity to present their findings.


Good project coordination will ensure that information developed in one project, but needed in other projects, can be easily integrated across the projects to meet the overall project objectives.  Because project leaders will be responsible for completing their individual projects, having someone that is involved with the overall project will ensure that material developed in individual projects is integrated across all projects and efficient coordination is occurring with the water acquisition program, managed by the National Fish and Wildlife Foundation.  Providing timely information about project progress and results will keep all stakeholders and those interested in the project informed as the project moves forward.  Providing results as the project progresses, rather than just providing summary reports at the end of the project will be important to the entire process of acquiring water rights and delivering water to the lake.