Development of a gis database for ground-water recharge assessment of the palouse basin
2003
Murray, J. | O’Geen, A. T. | McDaniel, P. A.
The advent of Geographic Information Systems (GIS) is bringing about the expansion of soil survey data into interdisciplinary research projects. A GIS database was developed for the Palouse Basin in northern Idaho and eastern Washington to identify areas where soil and geologic features are likely to impact ground-water recharge. Using GeoProcessing operations in ArcView, 1:24,000 soil survey data and surficial geology were combined. The resulting ArcView-based GIS coverage was used to delineate recharge mechanisms and classify recharge potential in the Palouse Basin. A database was developed using binary weighting and index overlay modeling methods to assign values to soil map units based on selected soil characteristics, including permeability rates, depth to bedrock, and the presence of perched water tables. These data were then linked to Basin recharge mechanisms to produce maps indicating the potential for deep percolation through soil and subsequent recharge to the local aquifer system. Results indicate that recharge through loess is the most spatially extensive recharge mechanism, operating over 71% of the total study area. Of this, approximately 2300 ha have high potential for recharge. Recharge through stream loss operates over 16% of the total study area, whereas percolation through localized fractures in bedrock is the least extensive recharge mechanism, operating over just 13% of the total study area. Although stream loss and infiltration along Basin margins occupy a limited spatial extent they have more land area rated as ‘high potential’ for recharge. There is lower recharge potential in the eastern portion of the Basin because of the presence of extensive hydraulically restrictive subsoil horizons.
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