Data Series 255
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AbstractThe Arroyo Colorado is in the lower Rio Grande Valley of southern Texas and extends from near Mission, Texas, eastward to the Laguna Madre estuarine and coastal marine system, which separates Padre Island from the Texas mainland. Streamflow in the Arroyo Colorado primarily is sustained by effluent from municipal wastewater-treatment plants along the stream banks. Since 1986, the tidal segment of the Arroyo Colorado from the port of Harlingen to the Laguna Madre has been designated by the State of Texas as an impaired water body because of low dissolved oxygen concentrations. Efforts to develop predictive water-quality models for the tidal segment of the Arroyo Colorado have been hampered by a lack of physical, biological, and biochemical data. Specifically, data on primary algal productivity, nutrient cycling, sediment deposition rates, and the relations between these processes and dissolved oxygen dynamics in the stream have been inadequate to support water-quality modeling efforts. The U.S. Geological Survey, in cooperation with the Texas Commission on Environmental Quality, did a study in 2006 to collect data associated with primary algal productivity, nutrient cycling, and dissolved oxygen dynamics in the tidal segment (2201) of the Arroyo Colorado near Rio Hondo. Specific objectives of the study were to (1) characterize water quality by measuring basic properties; (2) characterize the concentrations of carbon and nutrients, biochemical oxygen demand, total organic carbon, total suspended solids, and volatile suspended solids; (3) measure the seasonal differences of nutrient-dependent algal growth and algal production in the water column; (4) measure oxygen respiration or production rates; and (5) measure rates of sediment deposition. |
Roussel, M.C., Canova, M.G., Asquith, W.H., and Kiesling, R.L., 2007, Water-quality and ancillary data collected from the Arroyo Colorado near Rio Hondo, Texas, 2006: U.S. Geological Survey Data Series 255, 46 p.
Abstract
Introduction
Purpose and Scope
Description of Study Area
Acknowledgments
Methods of Investigation
Site Selection
Sampling/Monitoring and Analysis
Algal Productivity
Continuous Water-Quality Monitoring
Sedimentation
Discrete Samples
Algal Growth and Mortality
Bioassay Analysis
Phytoplankton and Zooplankton Analysis
Vertical Profiles
Data Treatment
Water-Quality and Ancillary Data
References
Appendix 1—Data collected at near-bottom and near-surface depths of the Arroyo Colorado near Rio Hondo, Texas
Appendix 2—Vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas
For additional information contact: Director, Texas Water Science Center U.S. Geological Survey 8027 Exchange Drive Austin, Texas 78754-4733 World Wide Web: http://tx.usgs.gov/ |
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