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Filters: Types: OGC WMS Layer (X) > partyWithName: Barbara J Mahler (X) > partyWithName: Oklahoma-Texas Water Science Center (X)

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Temporal patterns in glyphosate and atrazine concentrations were measured weekly by the U.S. Geological Survey (USGS) during the 2013 growing season in 100 small streams in the Midwestern United States. Concentrations also were measured every 2 days at a subset of 8 of the sites, all located in Missouri. Glyphosate was detected more frequently in urban streams than in agricultural streams, and at concentrations similar to those in streams with high agricultural land use in the watershed. In contrast, atrazine was detected more frequently and at higher concentrations in agricultural streams than in urban streams. This data release provides watershed characteristics and 2013 glyphosate and atrazine compound concentrations...
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The Edwards aquifer is a karst aquifer system that is a primary water source for a large part of central Texas including the city of San Antonio, Texas. These vector geospatial data represent the geographic extent of the contributing zones for the Northern, Barton Springs, and San Antonio segments of the Edwards aquifer. The contributing zone is defined as the drainage area of the Edwards Plateau that contributes surface water to the Edwards aquifer recharge zone. The recharge zone is where surface water and precipitation infiltrate into the outcrop of the rocks that compose the aquifer (see Ashworth and Hopkins, 1995, and George and others, 2011). References Ashworth, J.B., and Hopkins, Janie, 1995, Aquifers of...


    map background search result map search result map Concentrations of glyphosate and atrazine compounds in 100 Midwest United States streams in 2013 Contributing Zones of the San Antonio, Barton Springs, and Northern segments of the Edwards aquifer Contributing Zones of the San Antonio, Barton Springs, and Northern segments of the Edwards aquifer Concentrations of glyphosate and atrazine compounds in 100 Midwest United States streams in 2013