Changes in ecosystem services and runoff due to land use change in the watersheds of San Antonio, Texas /
The process of urbanization in San Antonio, Texas is resulting in transformation of land surfaces from rural to urban uses. This transformation could result in a loss of ecological services and also alter the hydrology of the affected watersheds involved. The purpose of this study was to quantify th...
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| Format: | Thesis eBook |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Summary: | The process of urbanization in San Antonio, Texas is resulting in transformation of land surfaces from rural to urban uses. This transformation could result in a loss of ecological services and also alter the hydrology of the affected watersheds involved. The purpose of this study was to quantify the degree of land use change in San Antonio from 1976 through 1991, estimate the economic value of natural resources, specifically those lost due to urbanization, and determine the impact these changes could have on stormwater peak flows. Remotely-sensed LANDSAT images of the area were used to determine the area of each land use/land cover class in each watershed. The economic value of the natural resources lost was assessed by applying an ecological service valuation model to each of the land use classes over the discreet time periods. Hydrologic peak flow models using the Soil Conservation Service Curve Number Method were developed and applied to each watershed for each discreet time period. Urbanization resulted in a substantial loss of agricultural lands in the fifteen-year time period studied, but the results were somewhat marred due to the limitations of using satellite images, specifically cloud cover and different land use classes having similar spectral signatures. There was an average reduction of 36.3% in the total value of natural resources in each area due to urbanization. The largest loss was seen in the 1976 to 1985 time period, a time of great economic growth in San Antonio. The sensitivity analysis showed the value assigned to agriculture to be the most sensitive parameter on the whole, so the results of the economic valuation model put great importance on the studies used as the basis for the model. The peak flows associated with each watershed increased from 0.505% to 3.802%. The small increases may be due to the difficulties with the land use classification or the broad-categoried curve numbers. This study indicates that critical services provided by nature are being lost due to urbanization. It also indicates that further research is needed to devise a more defendable way to quantify this loss. |
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| Item Description: | "Major subject: Agricultural Engineering". Vita. |
| Physical Description: | ix, 84 leaves : illustrations, maps ; 28 cm. Also available online. Issued also on microfiche from Lange Micrographics. |
| Bibliography: | Includes bibliographical references (leaves 65-70). |