F. WATER FLOW MODEL

This project will develop a decision-support tool to evaluate the effectiveness of proposed acquisitions of water rights from willing sellers to increase water delivery to Walker Lake. The tool's water flow model will include aspects of climate and evaporation from different water sources.

Researchers:

From DRI: Doug Boyle (PI), Division of Hydrologic Sciences (DHS); Greg Pohll (PI), DHS, Gregg Lamorey (Co-I), DHS; Rina Schumer, (Co-I), DHS; Tim Minor (Co-I), Division of Earth and Ecosystems (DEES), Eric McDonald (Co-I), DEES; Rosemary Carroll (Co-I), DHS
From UNR: Scott Tyler (PI), Department of Geologic Sciences and Engineering; Banmali Rawat (Co-I), Department of Electrical Engineering

Updates:

January 2008:

LIDAR data for Mason Valley was delivered on January 18, 2008, for use by this team and the project team charged with development of a water rights GIS database. The LIDAR data contains valuable spatial information on the locations of streams, ditches and drains for Mason Valley. This information is currently being used to develop the final digital elevation model (DEM) for the conceptual and numeric models for the Mason Valley. We hope there will be additional LIDAR data for Smith Valley available in the future otherwise we will have to proceed with the existing DEM.

The existing DEM (without the LIDAR information) is currently being used along with the available stream and ditch information to refine the MODFLOW groundwater modeling grid of the Mason Valley. The steady state MODFLOW model developed for Mason Valley is currently being tested and improved to accurately simulate the groundwater system over a historic time period. The development, testing, and evaluation of the hydrologic models of the headwater areas and Mason Valley are all ongoing.

February 2008:

A week-long field campaign was conducted in conjunction with the U.S. Geologic Survey to measure both soil temperatures at the Alternative Agriculture Test Stations and background groundwater inflows within the Walker River.

LIDAR data for Mason Valley was delivered to Projects 1 and 2 on January 18, 2008. The LIDAR data contains valuable spatial information on the locations of streams, ditches and drains for Mason Valley. This information is currently being used to develop the final digital elevation model (DEM) for the conceptual and numeric models for the Mason Valley. We hope there will be additional LIDAR data for Smith Valley provided to the Project 1 team sometime in the future; otherwise, we will have to proceed with the existing DEM.

The fiber optic cables installed at both Alternative Agriculture sites were tested and soil temperatures collected over a several day period in February. The testing showed very uniform soil temperatures and was consistent with the relatively uniform moisture contents observed. The testing was conducted prior to both germination and any difference in irrigation across the test plots and showed that soil temperatures could be readily used to infer soil moisture status and its variability across these fields.

March 2008:

Continued data analysis was conducted on information collected during joint field work with the USGS and at the alternative agriculture sites.

A compilation of the Distributed Temperature Sensing System and methodologies was submitted to the technical journal Water Resources Research as part of an invited Special Section on Methods in Hydrologic Science. Data presented in the manuscript and analysis were developed during testing and analysis of several DTS systems conducted at the University prior to our purchase of the Sensornet instrument.

The summary of the project was presented at the March 2008 Stakeholders Meeting in Hawthorne.

April 2008:

Field estimates of canal seepage were made in selected canals in basin.

Final DEM with streams and ditches in Mason Valley from new LIDAR data was completed, and will be used for the development and testing of hydro models. The transient MODFLOW model of Mason Valley and the steady state MODFLOW model of Smith Valley are under development.

The software package MODSIM is being used to represent the demand side of the watershed as the final DSS tool in the Walker.

Data processing of stream surveys is continuing and measurements at both alternative agriculture sites are currently underway.

May 2008:

Initial data analysis of field data and model development related to canal seepage estimates were made. Conceptual networks of streams and ditches in Mason Valley from new LIDAR improved DEM were developed for the hydrologic model development and testing effort. The transient MODFLOW model of Mason Valley and the steady state MODFLOW model of Smith Valley are still under development. Chris Garner attended custom MODSIM training in Fort Collins, CO to help with MODSIM applications in Mason and Smith Valleys. Several DRI faculty presented initial MODFLOW model results at the MODFLOW conference in Colorado.

During May 2008, a series of soil temperature profiles were collected showing clear response of the DTS (Distributed Temperature Sensing) system to both variations in soil moisture content, as well as infiltration rate. Using day and night time soil temperatures collected at the alternative agriculture sites prior to and just after sprinkler irrigation, estimates of the variation of soil moisture content across the 1 km long fiber optic cable were measured at 1 meter resolution. Moist areas of the experiment plot showed a larger difference in day minus night temperature, reflective of the higher thermal diffusivity of moist soil. At those portions of the field sites where the soil moisture in the upper 15 cm was low, the soil showed much smaller fluctuations due to limited heat transfer between the soil surface and the subsoil.

June 2008:

Analysis of canal seepage data collected in Mason Valley wildlife refuge continues. The steady state groundwater model of Mason Valley has been completed, and the final calibration of the transient groundwater model of Mason Valley is near completion.A groundwater characterization database for Smith Valley is also near completion.

A plan is being developed to collect water level and drawdown information in Smith Valley. Model development of Mason and Smith Valleys will begin when the GIS team has completed the final QA/QC version of ditches, drains and associated farm units.

Vertical temperature sensing platforms were installed and calibrated in the Wabuska reach of the Walker River. During July we are deploying a distributed temperature sensing fiber optic cable, to be used in conjunction with the vertical profiles, to record groundwater inflows through this anticipated gaining reach.

July 2008:

The analysis of canal seepage data collected in Mason Valley wildlife refuge continues. The steady state groundwater model has been completed, the final calibration of the transient groundwater model is near completion and will use data collected by the team in Project I, GIS Database Development. The Groundwater and MODSIM modeling groups have been interacting to coordinate interim model structure, parameters and results.

A groundwater characterization database for Smith Valley is near completion. A plan is being developed to collect water level and drawdown information in Smith Valley. Several farmers have been contacted for information.

Development of MODSIM models of Mason and Smith Valleys will begin soon when the quality assurance and control for ditch, drain, and associated farm unit data is complete.

Data logging of vertical temperatures in the Wabuska reach continued through July, as well as a campaign of soil temperature measurements on the alternative agriculture sites. The deployment of the fiber optic cable in the Wabuska reach was delayed to early August due to logistics of access to the field site, which are now resolved.

The soil temperature studies at the alternative agriculture sites are now showing excellent results in relating soil moisture to temperature lag at the 6" depth. In addition, irrigation efficiencies and variability in irrigation application are easily detected.

August 2008:

There are no updates this month.

September 2008:

The analysis of canal seepage data collected in Mason Valley wildlife refuge is still ongoing. The steady state groundwater model of Mason Valley has been completed. The final draft calibration of the transient groundwater model of Mason Valley has been completed and results are currently under review. A groundwater characterization database for Smith Valley is near completion and a plan is being developed to collect water level and drawdown information in Smith Valley – some of the farmers have been contacted by project staff for information. Final revisions to the headwater models are currently underway.

The Groundwater and MODSIM modeling groups have been interacting to coordinate interim model structure, parameters and results. Plans are underway to couple the MODFLOW groundwater model of Mason Valley to the MODSIM model – a sub-consultant will provide DRI research staff with necessary training in mid-September. MODSIM model development of Mason and Smith Valleys has begun and significant progress has been made – a draft MODSIM model has been implemented and is currently being calibrated and evaluated.

The following additional modifications to the existing MODSIM model are planned: inclusion of the demand side for Antelope Valley, upper East Walker (below Bridgeport Reservoir), and agricultural areas above Bridgeport Reservoir. The extent of the spatial detail of these areas represented in the MODSIM model will depend on the spatial extent of the information gathered by the Project 1 team in the next month or two.

Data logging and surveying of both the Wabuska Reach and Valley Vista sites were expanded in September to collect both low flow data (Wabuska) and during a period of fairly constant soil moisture (Valley Vista).

Additionally, nine abstracts were submitted for consideration by the American Geophysical Union for inclusion in the fall meeting that are a result of this project. Analysis of Valley Vista data was completed for presentation at the Geological Society of America annual meeting in October. A new publication resulting from the project work, "Environmental Temperature Sensing using Raman Spectra DTA Fiber-Optic Methods" was accepted for publication in the journal Water Resources Research.

October 2008:

The analysis of canal seepage data collected in Mason Valley wildlife refuge has been completed and seepage rates are implemented in the hydrologic models. The steady state and transient groundwater models of Mason Valley have been completed. The coupling of the MODFLOW and MODSIM models of Mason Valley are currently underway. Initial steady state and transient MODFLOW models of Smith Valley have been completed and are currently under review. The draft MODSIM and MODFLOW models of Smith Valley are currently being coupled.

The following additional modifications to the existing MODSIM model are underway: inclusion of the demand side for Antelope Valley, upper East Walker (below Bridgeport Reservoir) and agricultural areas above Bridgeport Reservoir. The extent of the spatial detail of these areas represented in the MODSIM model will depend on the spatial extent of the information gathered by the GIS Database Development team in the next few weeks.

Final revisions to the headwater models are currently underway. A final Wabuska stream survey was completed using fiber optic temperature sensing, showing evidence of groundwater inflows during low flow periods in that reach. A presentation on the Valley Vista soil temperature monitoring was presented at the annual meeting of the Geologic Society of America.

November 2008:

The coupling of the MODFLOW and MODSIM models of Mason Valley has been completed. Initial steady state and transient MODFLOW models of Smith Valley were completed and reviewed and are under final revision. The MODSIM and MODFLOW models of Smith Valley have been coupled, and a new MODSIM model of both the Mason and Smith Valleys is being developed.

The following additional modifications to the final MODSIM model are still underway: inclusion of the demand side for Antelope Valley, upper East Walker (below Bridgeport Reservoir), and agricultural areas above Bridgeport Reservoir. The extent of the spatial detail of these areas represented in the MODSIM model will depend on the spatial extent of the information gathered by the GIS Database Development team in the next week. Final revisions to the headwater models have been completed.

The installations at the Wabuska gauge site were dismantled, and the site was returned to pristine condition. Analysis of data collected during the last round of measurements using the fiber optic cable is under way, and the field analysis portion of the groundwater/surface water exchange studies has now been completed.

Coming up