http://hdl.handle.net/1969.1/88066 2013-06-20T00:32:18Z 2013-06-20T00:32:18Z http://hdl.handle.net/1969.1/85895 2011-03-31T20:22:05Z 2008-10-10T20:54:52Z

Environmentally related water trading, transfers and environmental flows: welfare, water demand and flows This dissertation reports on economic studies of Texas Interbasin Water Transfers (IBT) as a way to lessen expected water shortages, Texas minimum freshwater inflows requirements (FWIB) to protect environmental flows and the general policy setup when generators of environmental commodities might be able to sell credits in multiple markets. The Texas-based studies address economic, hydrological and environmental impacts, focusing on welfare gain, water demand, environmental flows and complementary relationship of environmental commodities. Conduct of the two Texas studies required development of a Texas surface water model. The developed model incorporates: (a) uncertain weather patterns and supply of water; (b) river flows in most of the Texas river basins - twenty-one basins excluding only the Rio Grande; (c) demand for water by agricultural, municipal and industrial/ mining water; (d) IBT possibilities; (e) evaporation losses; and (e) return flows across the modeled basins. In studying the interbasin water transfers, three IBT projects where chosen as economically justified relocating water largely for municipal and industrial/mining uses. These IBT projects had the effect of increasing water use and instream flows in the IBT destination basins, but decreasing those in the source basins. In studying the freshwater inflows the study revealed that the suggested inflow constraints were met on average and that the inflow levels for two basins had to be lowered for the constraints to be feasible. This suggests that the contemplated limits are too high and that either multiple basin or flow dependent limits need to be developed. The results also showed that under the average FWIB constraints and IBT implementation, welfare loss from the FWIB constraints was greatly reduced due to the IBT projects which were simultaneously implemented. In the study of multiple environmental commodity markets, the results indicate that generated credits should be sold in multiple markets only when market caps are set up close to socially efficient (so called first-best) caps: this implies that marginal benefit curves are very steep. However, restricting selling into just single market achieved the same net benefits as multiple markets did when market caps were set up at levels less than the first-best caps.

2008-10-10T20:54:52Z http://hdl.handle.net/1969.1/3833 2011-06-22T13:17:24Z 2006-08-16T19:05:37Z

Incorporating salinity considerations in water availability modeling This research focused on expanding the capabilities of the Water Rights Analysis Package (WRAP) for incorporating salinity considerations in assessments of water availability. A simulation modeling approach was used to address this issue and a generalized simulation model called WRAP-SALT was developed. The Brazos River Basin served as a case study to test the simulation approach adopted by the model. The simulation model adopts a generalized modeling approach applicable to any river basin system. The model tracks salinity throughout a river basin system over different periods of time for alternative scenarios of water use, reservoir system operating policies, and salt control mechanisms. The model was applied to the Brazos River Basin considering different management scenarios and the results obtained were analyzed. Reservoir reliabilities were assessed under user imposed salinity constraints. It was observed that the water supply reliabilities decreased significantly if salinity constraints were considered. Salt control dams proposed by the U.S. Army Corps of Engineers were also incorporated in the simulation of the river basin. It was observed that salinity in the main stem of the Brazos River was significantly reduced. However, no significant improvement was observed in water supply reliabilities.

2006-08-16T19:05:37Z http://hdl.handle.net/1969.1/192 2011-06-20T18:48:38Z 2004-09-30T01:45:29Z

A statistical model for estimating mean annual and mean monthly flows at ungaged locations Prediction of flow is necessary for planning and management of water resources. The objective of this study is to estimate mean annual flows for the USA and mean monthly flows for the rivers of central Texas based on the precipitation and their watershed characteristics. Flow varies largely with topographic and climatic parameters and hence generalization of runoff models is difficult. This model aims at providing a prediction at ungaged locations with very few parameters that are easily available and measurable. Scatter in predicted data will be seen at the annual and monthly time scale in the range selected for each data. This model will work on annual and monthly means to reduce the scatter and produce better estimates.

2004-09-30T01:45:29Z http://hdl.handle.net/1969.1/121 2011-06-20T18:47:33Z 2004-09-30T01:42:56Z

Development of an ArcGIS interface and design of a geodatabase for the soil and water assessment tool This project presents the development and design of a comprehensive interface coupled with a geodatabase (ArcGISwat 2003), for the Soil and Water Assessment Tool (SWAT). SWAT is a hydrologically distributed, lumped parameter model that runs on a continuous time step. The quantity and extensive detail of the spatial and hydrologic data, involved in the input and output, both make SWAT highly complex. A new interface, that will manage the input/output (I/O) process, is being developed using the Geodatabase object model and concepts from hydrological data models such as ArcHydro. It also incorporates uncertainty analysis on the process of modeling. This interface aims to further direct communication and integration with other hydrologic models, consequently increasing efficiency and diminishing modeling time. A case study is presented in order to demonstrate a common watershed-modeling task, which utilizes SWAT and ArcGIS-SWAT2003.

2004-09-30T01:42:56Z