http://hdl.handle.net/1969.1/2827 2013-06-19T17:37:43Z 2013-06-19T17:37:43Z http://hdl.handle.net/1969.1/149051 2013-06-19T06:11:33Z 2012-01-01T00:00:00Z

2012 Bacterial Source Tracking - State of the Science Conference Conference Proceedings The 2012 Bacterial Source Tracking - State of the Science Conference was held February 28-29 at the T Bar M Resort and Conference Center in New Braunfels, Texas. Academia involved in BST analysis; state, federal, and regional agency personnel; elected officials; and other interested persons were targeted through various media outlets. Prior to the conference, the Texas State Soil and Water Conservation Board (TSSWCB) queried state and federal agencies about what their wants and needs in regards to the state of BST science. Staff from the U.S. Environmental Protection Agency (EPA), Texas Parks and Wildlife Department (TPWD), Texas Commission on Environmental Quality (TCEQ) and others were asked to identify questions and issues that should be included in conference presentations and discussion.

2012-01-01T00:00:00Z http://hdl.handle.net/1969.1/149050 2013-06-18T06:02:54Z 2012-06-01T00:00:00Z

SWAT Modeling of the Arroyo Colorado Watershed A model setup of the Soil and Water Assessment Tool (SWAT) watershed model was developed to simulate flow and selected water quality parameters for the Arroyo Colorado watershed in South Texas. The model simulates flow, transport of sediment and nutrients, water temperature, dissolved oxygen, and biochemical oxygen demand. The model can also be used to estimate a total maximum daily load for the selected water quality parameters in the Arroyo Colorado. The model was calibrated and tested for flow with data measured during 2000–2009 at two streamflow-gaging stations. The flow was calibrated satisfactorily at monthly and daily intervals. In addition, the model was calibrated and tested sequentially for suspended sediment, orthophosphate, total phosphorus, nitrate nitrogen, ammonia nitrogen, total nitrogen, and dissolved oxygen, using data from 2000–2009. The simulated loads or concentrations of the selected water quality constituents generally matched the measured counterparts available for the calibration and validation periods. Two watershed scenarios were simulated for the years 2015 and 2025 after estimation of land cover maps for those years. The scenarios were intended to identify a suite of best management practices (BMPs) to address the depressed dissolved oxygen problem in the watershed.

2012-06-01T00:00:00Z http://hdl.handle.net/1969.1/149049 2013-06-18T06:02:53Z 2012-05-01T00:00:00Z

2011-2012 Efficient Irrigation for Water Conservation in the Rio Grande Basin Progress and Accomplishments During the past year, the RGBI Economics Team completed various technical reports and professional journals and presented findings on RGBI water-resource issues to local, statewide, and national audiences. Key topics included: 1) business economics of desalination water-treatment facilities; 2) mitigation cost investigations of increased off-site sediment runoff and nutrients associated with biofuels production; 3) economic and water conservation effects of drip irrigation compared to traditional strategies such as furrow or flood; 4) health-related economic analysis of water quality and household treatment/delivery systems; 5) impacts of analytical techniques involving discounting for time; and 6) regional market economics affected by changing water supply and demand from dynamic climate conditions and increasing population.

2012-05-01T00:00:00Z http://hdl.handle.net/1969.1/149048 2013-06-18T06:02:50Z 2012-05-01T00:00:00Z

A Multivariate Water Quality Investigation of Select Drainage Ditches in the Arroyo Colorado River Watershed, Texas Drainage ditches are widely used for agricultural water management to help remove excess water from fields, which mitigates the effects of water logging and salinization. These ditches act as a direct hydraulic link between the agricultural field and streams and rivers. As such, there is an increasing concern that drainage ditches can act as conduits for nutrient transport and, in conjunction with other point and nonpoint sources, can contribute to eutrophication and decreased dissolved oxygen levels in receiving water bodies. Studies have linked drainage ditches to hypoxia in the Gulf of Mexico and eutrophication of the Great Lakes (Dagg and Breed, 2003; Moore et al., 2010). However, there is also evidence suggesting that drainage ditches can help attenuate the loadings of phosphorus and suspended sediments (R. Kröger et al., 2008) and thus foster water quality improvements at a watershed scale. There is a growing interest in understanding the nutrient behavior in drainage ditches both in the United States (Bhattarai et al. 2009; Moore, et al. 2010; Ahiablame et al. 2011) as well as other parts of the world (Nguyen and Sukias 2002; Leone et al. 2008; Bonaiti and Borin 2010).

2012-05-01T00:00:00Z