Hydrological Information Products for the Off-Project Water Program of the Klamath Basin Restoration Agreement

U.S. Geological Survey Open-File Report 2012-1199 U.S. Department of the Interior

By Daniel T. Snyder, John C. Risley, and Jonathan V. Haynes

Prepared in cooperation with The Klamath Tribes

Access complete report at: https://pubs.usgs.gov/of/2012/1199

Suggested citation: Snyder, D.T., Risley, J.C., and Haynes, J.V., 2012, Hydrological information products for the Off-Project Water Program of the Klamath Basin Restoration Agreement: U.S. Geological Survey Open-File Report 2012–1199, 17 p., https://pubs.usgs.gov/of/2012/1199

Summary The Klamath Basin Restoration Agreement (KBRA) was developed by a diverse group of stakeholders, Federal and State resource management agencies, Tribal representatives, and interest groups to provide a comprehensive solution to ecological and water-supply issues in the Klamath Basin. The Off-Project Water Program (OPWP), one component of the KBRA, has as one of its purposes to permanently provide an additional 30,000 acre-feet of water per year on an average annual basis to Upper Klamath Lake through “voluntary retirement of water rights or water uses or other means as agreed to by the Klamath Tribes, to improve fisheries habitat and also provide for stability of irrigation water deliveries.” The geographic area where the water rights could be retired encompasses approximately 1,900 square miles. The OPWP area is defined as including the Sprague River drainage, the Sycan River drainage downstream of Sycan Marsh, the Wood River drainage, and the Williamson River drainage from Kirk Reef at the southern end of Klamath Marsh downstream to the confluence with the Sprague River. Extensive, broad, flat, poorly drained uplands, valleys, and wetlands characterize much of the study area. Irrigation is almost entirely used for pasture. To assist parties involved with decisionmaking and implementation of the OPWP, the U.S. Geological Survey (USGS), in cooperation with the Klamath Tribes and other stakeholders, created five hydrological i nformation products. These products include GIS digital maps and datasets containing spatial information on evapotranspiration, subirrigation indicators, water rights, subbasin streamflow statistics, and return-flow indicators. The evapotranspiration (ET) datasets were created under contract for this study by Evapotranspiration, Plus, LLC, of Twin Falls, Idaho. A high-resolution remote sensing technique known as Mapping Evapotranspiration at High Resolution and Internalized Calibration (METRIC) was used to create estimates of the spatial distribution of ET. The METRIC technique uses thermal infrared Landsat imagery to quantify actual evapotranspiration at a 30-meter resolution that can be related to individual irrigated fields. Because evaporation uses heat energy, ground surfaces with large ET rates are left cooler as a result of ET than ground surfaces that have less ET. As a consequence, irrigated fields appear in the Landsat images as cooler than nonirrigated fields. Products produced from this study include total seasonal and total monthly (April–October) actual evapotranspiration maps for 2004 (a dry year) and 2006 (a wet year). Maps showing indicators of natural subirrigation were also provided by this study. “Subirrigation” as used here is the evapotranspiration of shallow groundwater by plants with roots that penetrate to or near the water table. Subirrigation often occurs at locations where the water table is at or above the plant rooting depth. Natural consumptive use by plants diminishes the benefit of retiring water rights in subirrigated areas. Some agricultural production may be possible, however, on subirrigated lands for which water rights are retired. Because of the difficulty in precisely mapping and quantifying subirrigation, this study presents several sources of spatially mapped data that can be used as indicators of higher subirrigation probability. These include the floodplain boundaries defined by stream geomorphology, water-table depth defined in Natural Resources Conservation Service (NRCS) soil surveys, and soil rooting depth defined in NRCS soil surveys. The two water-rights mapping products created in the study were “points of diversion” (POD) and “place of use” (POU) for surface-water irrigation rights. To create these maps, all surface-water rights data, decrees, certificates, permits, and unadjudicated claims within the entire 1,900 square mile study area were aggregated into a common GIS geodatabase. Surface-water irrigation rights within a 5-mile buffer of the study area were then selected and identified. The POU area was then totaled by water right for primary and supplemental water rights. The maximum annual volume (acre-feet) allowed under each water right also was calculated using the POU area and duty (allowable annual irrigation application in feet). In cases where a water right has more than one designated POD, the total volume for the water right was equally distributed to each POD listed for the water right. Because of this, mapped distribution of diversion rates for some rights may differ from actual practice. Water-right information in the map products was from digital datasets obtained from the Oregon Water Resources Department and was, at the time acquired, the best available compilation of water-right information available. Because the completeness and accuracy of the water-right data could not be verified, users are encouraged to check directly with the Oregon Water Resources Department where specific information on individual rights or locations is essential. A dataset containing streamflow statistics for 72 subbasins in the study area was created for the study area. The statistics include annual flow durations (5-, 10-, 25-, 50-, and 95-percent exceedances) and 7-day, 10-year (7Q10) and 7-day, 2-year (7Q2) low flows, and were computed using regional regression equations based on measured streamflow records in the region. Daily streamflow records used were adjusted as needed for crop consumptive use; therefore the statistics represent streamflow under more natural conditions as though irrigation diversions did not exist. Statistics are provided for flow rates resulting from streamflow originating from within the entire drainage area upstream of the subbasin pour point (referring to the outlet of the contributing drainage basin). The statistics were computed for the purpose of providing decision makers with the ability to estimate streamflow that would be expected after water conservation techniques have been implemented or a water right has been retired. A final product from the study are datasets of indicators of the potential for subsurface return flow of irrigation water from agricultural areas to nearby streams. The datasets contain information on factors such as proximity to surface-water features, geomorphic floodplain characteristics, and depth to water. The digital data, metadata, and example illustrations for the datasets described in this report are available on-line from the USGS Water Resources National Spatial Data Infrastructure (NSDI) Node Website http://water.usgs.gov/lookup/getgislist or from the U.S. Government website DATA.gov at http://www.data.gov with links provided in a Microsoft® Excel® workbook in appendix A.

Introduction

Program Background The Klamath Basin Restoration Agreement (KBRA) was developed by a diverse group of stakeholders, Federal and State resource management agencies, Tribal representatives, and interest groups to provide a comprehensive solution to ecological and water-supply issues in the basin. The KBRA covers the entire Klamath Basin, from headwater areas in southern Oregon and northern California to the Pacific Ocean, and addresses a wide range of issues that include hydropower, fisheries, and water resources. The Water Resources Program (Part IV of the KBRA) includes a section (16) known as the Off-Project Water Program (OPWP) (Klamath Basin Restoration Agreement, 2010, p. 105).

Program Goals The primary goals of the OPWP include developing an Off-Project Water Settlement to resolve upper basin water issues, improve fish habitat, and provide for stability in irrigation deliveries (Klamath Basin Restoration Agreement, 2010, p. 105). One of the approaches to achieving these objectives is a water-use retirement program. The water-use retirement program is an effort to permanently provide an additional 30,000 acre-ft of water per year on an average annual basis to Upper Klamath Lake through “voluntary retirement of water rights or water uses, or other means as agreed to by the Klamath Tribes, to improve fisheries habitat and also provide for stability of irrigation water deliveries” (Klamath Basin Restoration Agreement, 2010, p. 105–111). The KBRA sets a 24-month window after the “effective date” for development of a proposal for the Off-Project Water Settlement. There is interest on the part of the Klamath Watershed Partnership (and others) in having a decisionmaking process in place before this time line. To assist parties in the OPWP involved with decisionmaking and implementation, the USGS proposed a two-phase approach. The first phase, which is described in this report, includes compilation and evaluation of relevant existing work and data in the upper basin, and synthesizing that information into a set of five hydrological information products. These products include GIS digital maps and datasets containing spatial information on evapotranspiration, subirrigation indicators, water rights, subbasin streamflow statistics, and return-flow indicators. Should efforts continue, a second phase could be developed to implement a monitoring program to evaluate the level of success of the first phase and to address additional information needs. Understanding the response of streams and groundwater to various land-use changes (such as reduction of irrigation or changes in land management) in particular areas is important to maximizing the benefits to streams and to Upper Klamath Lake while minimizing the impacts to the agricultural community. The hydrology of the region is such that the response to changes in land use will vary from place to place. Because of this, the benefit to the stream from a particular change in land or water use may be greater in one area than another.

Description of Project Area The OPWP area is defined in the KBRA as including the Sprague River drainage, the Sycan River drainage downstream of Sycan Marsh, the Wood River drainage, and the Williamson River drainage from Kirk Reef at the southern end of Klamath Marsh downstream to the confluence with the Sprague River, encompassing a total area of approximately 1,900 mi2. Individually, the Sprague, Williamson, and Wood Rivers provide about 33, 18, and 16 percent, respectively, of the total inflow to Upper Klamath Lake and together account for two-thirds of the total inflow (Hubbard, 1970; Kann and Walker, 1999, table 3). Extensive, broad, flat, poorly drained uplands, valleys, and wetlands characterize much of the study area. Elevations in the study area range from about 4,100 ft at Upper Klamath Lake to greater than 9,000 ft in the Cascade Range. In general, land use in the Williamson River, Sprague River, and Wood River basins varies with elevation. At the lowest elevations, adjacent to the major rivers, agricultural lands (primarily irrigated pasture) predominate. Rangelands primarily are on the tablelands, benches, and terraces, and forest is predominant on the slopes of buttes and mountains. Livestock grazing can occur on irrigated pastureland, rangeland, and forestland throughout the study area. Average annual precipitation in the area ranges from as low as about 15 in. near Upper Klamath Lake to about 65 in. at Crater Lake with most precipitation occurring largely as snow in the fall and winter (Western Regional Climate Center, 2012).

Previous Studies and Water Conservation Programs Recent studies in the Upper Klamath, Wood River, and Sprague River basins provided a foundation for many of the analyses made for this current study. A study of the regional groundwater hydrology of the Upper Klamath Basin is presented in Gannett and others (2007) and includes discussions of the hydrogeologic units, hydrologic budget, and configuration of the groundwater-flow system. Although the scale of this study is less useful for site-specific analysis, it provides a framework for analysis of the hydrology of the OPWP area. Carpenter and others (2009) provided a comprehensive analysis of hydrologic and water-quality conditions during restoration of the Wood River wetland for 2003–05. In their study, they developed a water budget for the wetland in addition to analyzing the mechanics of groundwater and soil moisture storage. Risley and others (2008) developed streamflow regression models used in this study to estimate a suite of streamflow statistics in study area subbasins. The Natural Resources Conservation Service (2009) presented findings from the Sprague River Conservation Effects Assessment Project (CEAP). Their report documented the effects of water conservation practices on private irrigated lowlands and uplands using field monitoring and hydrologic computer model simulations. Watershed Sciences LCC (2000) conducted a Forward-Looking Infrared (FLIR) survey flown in August 1999 for parts of the Upper Klamath Basin that collected both thermal infrared and color videography to map stream temperatures that can be used to identify point locations where return flows enter streams.

Purpose of This Report This report summarizes and provides details on information products created by the USGS for the OPWP and its implementation. These products include a set of digital maps in GIS (ArcMap) format that can be used together as overlays to help evaluate the relative benefits of reducing or curtailing water use in various areas. The maps are not intended to drive the decisionmaking process, but to inform the process. It is envisioned that there will be many additional considerations affecting decisions. The digital maps created for this study, and described below in more detail, are (1) evapotranspiration, (2) subirrigation indicators, (3) water rights, (4) subbasin streamflow statistics, and (5) irrigation return-flow indicators.

Access to Data, Metadata, and Example Illustrations The digital data, metadata, and example illustrations for the datasets described in this report are available on-line from the USGS Water Resources National Spatial Data Infrastructure (NSDI) Node Website (U.S. Geological Survey, 2010c) or from the U.S. Government Website DATA.gov (2012). Appendix A consists of a Microsoft® Excel® workbook listing each dataset and URL links to the website for the dataset, metadata, and example illustrations.

Evapotranspiration Mapping

Development Maps quantifying evapotranspiration (ET) over the entire landscape included in the OPWP were produced under contract for this study by Evapotranspiration, Plus, LLC, of Twin Falls, Idaho. The maps were created using a high-resolution remote sensing technique first developed by the University of Idaho (Allen and others, 2007a, 2007b). The technique known as “Mapping EvapoTranspiration at High Resolution and Internalized Calibration” (METRIC) uses Landsat imagery to estimate monthly actual evapotranspiration at 30-m resolution that can be related to individual irrigated fields. For the KBRA OPWP study, METRIC was applied to 2 separate years of growing season data for which suitable Landsat imagery was available, representing wet (2006) and dry (2004) years. By using these 2 years, it was possible to develop a range of likely actual ET over varied climate conditions. A small number of irrigated areas in the extreme eastern part of the Sprague River basin were not covered by the selected Landsat images used in the METRIC analysis. For these areas, ET was estimated using more traditional approaches that used standard ET models and crop coefficients combined with knowledge of crop and vegetation types. The METRIC procedure uses thermal infrared images from Landsat satellites to quantify ET. Because evaporation uses heat energy, ground surfaces with large ET rates are left cooler than ground surfaces that have less ET. As a consequence, irrigated fields appear on the images as being cooler than nonirrigated fields. The METRIC model is internally calibrated using ground-based reference ET. Both the rate and spatial distribution of ET can be efficiently and accurately quantified. A major advantage of using METRIC over conventional methods of estimating ET that use crop coefficient curves is that neither the crop development stages nor the specific crop type need to be known. In addition to ET, the fraction of reference crop evapotranspiration (ETrF) also is computed by METRIC. The alfalfa reference evapotranspiration (ETr), computed using local weather station meteorological data, is needed in calibrating METRIC to a specific study area. Previous studies have shown that the error between ET estimated from METRIC and measured from lysimeters daily and monthly for various crops and land uses in other areas has been from 1 to 4 percent (Allen and others, 2007b). For the current study, the accuracy of the METRIC ET values for irrigated areas was estimated as 10 percent for seasonal total ET values and 20 percent for monthly ET values (R.G. Allen, Evapotranspiration, Plus, LLC, written commun., 2011). The accuracy of the METRIC ET values for nonirrigated areas was estimated as 20 percent for seasonal total ET values and 40 percent for monthly ET values (R.G. Allen, Evapotranspiration, Plus, LLC, written commun., 2011). These larger values for estimated accuracy relative to other studies are a result of a number of factors including the limited availability of Landsat images not impeded by cloud cover or sensor failure during the period of interest and the heterogeneity of the study area with regard to vegetation, terrain, and soils. When making comparisons between individual areas of actual evapotranspiration, the relative difference between the areas likely has a much better accuracy than the accuracy of the absolute values of actual evapotranspiration for the individual areas. Products produced from this study include total seasonal and total monthly (April–October) actual evapotranspiration maps, in millimeters, for 2004 (dry year) and 2006 (wet year) and Landsat image maps for April–November 2004 and April–November 2006. Full details regarding Landsat image processing, METRIC calibration, and map production for this study are provided in separate reports written by the contractor and included in the GIS metadata (Evapotranspiration, Plus, LLC, 2011a, 2011b, 2011c).

Subirrigation Indicators

Definition “Subirrigation”