Water does not abide political boundaries. Over the millennia the hydrologic cycle has carved watersheds and river basins above the land, and aquifers below. These natural boundaries are part of a fluid, dynamic process. The lumpy political boundaries of counties and states frequently overlay multiple watersheds, river basins, and aquifers. Most policy decisions are conceived of, negotiated at, and implemented with respect to political rather than natural boundaries. For many policies this is appropriate; for water it is not.
The scientific community has recognized the need to address water issues in the context of watersheds and river basins since the inception of the U.S. Geological Survey. Recently, policy makers have begun to see the merits of developing and administering water policy within natural as opposed to political boundaries. Unfortunately, most of the data related to water use collected by state and federal agencies are compiled at the county and state levels. To conduct analyses at the watershed and river basin level, these data must first be converted. The assumption most frequently made to facilitate this conversion is that water use is evenly distributed throughout the political unit. Therefore, if 50% of a county is within a given watershed then 50% of the county’s water withdrawals are attributed to that watershed. This land-area based assumption will inevitably lead to mistakes over-allocation of withdrawals in some watersheds and under-allocation in others. The question is, Do these mistakes matter?
This site maps Georgia’s agricultural permits and calculates the magnitude and direction of mistakes the land-area based assumption would make in each of the state’s 52 watersheds. The data are also aggregated up to the river basin level.
The information provided here is the outgrowth of Peter Foster’s Master of Science thesis in the Department of Agricultural and Applied Economics at the University of Georgia, under the direction of Jeffrey D. Mullen, Warren Kriesel, and Jack H. Houston. We hope you find the maps, charts, and tables in this site useful. Our intention is to incorporate similar analyses for water use by other sectors in the future.