Center Looking southwest across Mosier Valley toward Mt. Hood, Oregon. Newly planted cherry trees (foreground) transition into mature cherry trees (red foliage) with grape vineyards in the backgroud (yellow foliage). (Photograph taken by Jonathan Haynes, U.S. Geological Survey, 2007). Right Looking southwest along the Columbia RIver toward the Mosier syncline and the the City of Mosier, Oregon.
Repeat sampling and age tracers were used to examine trends in nitrate, arsenic, and uranium concentrations in groundwater beneath irrigated cropland. Much higher nitrate concentrations in shallow modern groundwater were observed at both the Columbia Plateau and High Plains sites (median values of 10.2 and 15.4 mg/L as N, respectively) than in groundwater that recharged prior to the onset of intensive irrigation (median values of <1 and <4 mg/L as N, respectively). Repeat sampling of these well networks indicates that high nitrate concentrations in modern, shallow groundwater have been sustained for decades, posing a future risk to older, deeper groundwater used for drinking water. In fact, nitrate concentrations in older modern water (30−60 years since recharge) at the High Plains site have increased in the past decade. Groundwater irrigated areas in the Columbia Plateau tend to have higher nitrate concentrations in groundwater than continued...
Lower left: Map showing select groups of wells with similar hydraulic response within portions of the Umatilla Basin, Oregon. Hydrographs showing the trend lines of spring median water levels for select groups of wells with similar hydraulic response in the Umatilla Basin, Oregon (East-West groups). (See figures 10 and 11B, respectively, in the report.) Center foreground: Map showing distribution of groundwater-level trends in the Columbia Plateau Regional Aquifer System for the period 1968-2009. Red circles indicate groundwater-level declines, yellow circles indicate little or no change in groundwater levels, and blue circles indicate groundwater-level rises. Circle size is representative of magnitude of change. (See figure 8 in the report.) Lower right: Map showing select groups of wells with similar hydraulic response within portions of the Palouse Slope and the Columbia Basin Ground Water Management Area, Washington. Hydrographs showing the trend lines of spring median water levels for groups of wells with similar hydraulic response in the vicinity of the Palouse Slope and the Columbia Basin Ground Water Management Area, Washington (Eastern Flowpath groups). (See figures 15 and 17, respectively, in the report) Background: Photograph of Frenchman's Coulee in the vicinity of Quincy, Washington.
Upper Klamath Lake (UKL) is the source of the Klamath River that flows through southern Oregon and northern California. The UKL Basin provides water for 81,000 + ha (200,000+ acres) of irrigation on the U.S. Bureau of Reclamation Klamath Project located downstream of the UKL Basin. Irrigated agriculture also occurs along the tributaries to UKL. During 2013-2016, water rights calls resulted in various levels of curtailment of irrigation diversions from the tributaries to UKL. However, information on the extent of curtailment, how much irrigation water was saved, and its impact on the UKL is unknown. In this study, we combined Landsat-based actual evapotranspiration (ETa) data obtained from the Operational Simplified Surface Energy Balance model with gridded precipitation and U.S. Geological Survey station discharge data to evaluate the hydrologic impact of the curtailment program. Analysis was performed for 2004, 2006, 2008-2010 (base years), and 2013-2016 (target years) over irrigated areas above UKL. Our results indicate that the savings from the curtailment program over the June to September time period were highest during 2013 and declined in each of the following years. The total on-field water savings was approximately 60 hm 3 in 2013 and 2014, 44 hm 3 in 2015, and 32 hm 3 in 2016(1 hm3 = 10,000 m 3 or 810.7 ac-ft). The instream water flow changes or extra water available were 92, 68, 45, and 26 hm 3 , respectively, for 2013, 2014, 2015, and 2016. Highest water savings came from pasture and wetlands. Alfalfa showed the most decline in water use among grain crops. The resulting extra water available from the curtailment contributed to a maximum of 19% of the lake inflows and 50% of the lake volume. The Landsat-based ETa and other remote sensing datasets used in this study can be used to monitor crop water use at the irrigation district scale and to quantify water savings as a result of land-water management changes.
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