Richard N Slattery

Understanding nitrate dynamics in groundwater systems as a function of climatic conditions, especially during contrasting patterns of drought and wet cycles, is limited by a lack of temporal and spatial data. Nitrate sensors have the capability for making accurate, high-frequency measurements of nitrate in situ, but have not yet been evaluated for long-term use in groundwater wells. We measured in

IntroductionIn 2016, the U.S. Geological Survey (USGS), in cooperation with the San Antonio Water System, began a study to refine previously derived estimates of groundwater outflows from Medina and Diversion Lakes in south-central Texas near San Antonio. When full, Medina and Diversion Lakes (hereinafter referred to as the Medina/Diversion Lake system) (fig. 1) impound approximately 255,000 acre-

In January 2001, the U.S. Geological Survey—in cooperation with the Edwards Aquifer Authority—began a study to refine and, if possible, extend previously derived (1995–96) relations between the stage in Medina Lake and recharge to the Edwards aquifer to include the effects of reservoir stages below 1,018 feet and greater than 1,046 feet above National Geodetic Vertical Datum of 1929. The principal

The potential effects of chemicals in rivers and streams on human health or the ecology have long been a source of concern to water managers. Chemicals in rivers may result from natural or anthropogenic sources (such as industrial or residential practices) which are commonly associated with urbanized watersheds. The U.S. Geological Survey, in cooperation with the San Antonio Water System, examined

The U.S. Geological Survey-in cooperation with the U.S. Army Corps of Engineers, The Nature Conservancy, the Real Edwards Conservation and Reclamation District, and the Texas Parks and Wildlife Department-investigated streamflow gain and loss and water quality in the upper Nueces River Basin, south-central Texas, specifically in the watersheds of the West Nueces, Nueces, Dry Frio, Frio, and Sabina

Woody vegetation, including ashe juniper (Juniperus ashei), has encroached on some areas in central Texas that were historically oak grassland savannah. Encroachment of woody vegetation is generally attributed to overgrazing and fire suppression. Removing the ashe juniper and allowing native grasses to reestablish in the area as a brush management conservation practice (hereinafter referred to as

The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Natural Resources Conservation Service, the Edwards Aquifer Authority, and the Texas Parks and Wildlife Department, collected rainfall, streamflow, evapotranspiration, and stormflow water-quality data at the Laurel Canyon Creek watershed, within the Government Canyon State Natural Area, Bexar County, Tex. The purpos

During August 2006-December 2009, the U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, Fort Worth District, collected rainfall and evapotranspiration data to help characterize the hydrology of the Nueces River Basin, Texas. The USGS installed and operated a station to collect continuous (30-minute interval) rainfall and evapotranspiration data in southwest Medin

The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Natural Resources Conservation Service, the Edwards Region Grazing Lands Conservation Initiative, the Texas State Soil and Water Conservation Board, the San Antonio River Authority, the Edwards Aquifer Authority, Texas Parks and Wildlife, the Guadalupe Blanco River Authority, and the San Antonio Water System, evalua

The U.S. Geological Survey, in cooperation with the Edwards Aquifer Authority, assessed available streamflow data in the Guadalupe River Basin to determine streamflow gains and losses and the relative contribution of flow from major springs - Comal Springs, San Marcos Springs, and Hueco Springs - to streamflow in reaches of the Guadalupe River and its tributaries. The assessment is based primarily

The U.S. Geological Survey collected rainfall, streamflow, evapotranspiration, and rainfall and stormflow water-quality data from seven sites in two adjacent watersheds in the Honey Creek State Natural Area, Comal County, Texas, during August 2001–September 2003, in cooperation with the U.S. Department of Agriculture, Natural Resources Conservation Service, and the San Antonio Water System. Data c

The Edwards aquifer is one of the most productive carbonate aquifers in the Nation. The dissolution-modified, faulted limestone aquifer is the sole source of public water supply for San Antonio, Texas (fig. 1) and is the major source of water for Bexar County. In addition to providing public water supply to more than 1 million people, the Edwards aquifer supplies large quantities of water for agri