ECONOMIC AND ENVIRONMENTAL IMPACTS OF WATER-QUALITY PROTECTION POLICIES .2. APPLICATION TO THE CENTRAL HIGH-PLAINS

A three-stage modeling framework is applied to evaluate the potential economic and environmental impacts of agricultural groundwater protect ion policies in the Central High Plains Region. Three alternative poli cies (limitations on total nitrogen applications, limitations on unit- area nitrogen applications, and restrictions on the use of selected he rbicides) are compared to a baseline scenario that reflects the absenc e of any form of groundwater quality protection measures. In general, nitrogen restrictions are more effective in reducing nitrate loadings in percolation water if implemented on a unit-area basis rather than a s a total (farm level) restriction. In contrast, the total restriction is more effective in controlling runoff losses of nitrogen. Both nitr ogen restrictions have significant impacts on crop production levels a nd regional agricultural income, while the economic consequences of th e pesticide restriction are much less pronounced. The proposed regiona l modeling framework provides critical information necessary to assess the economic and environmental tradeoffs of policy alternatives aimed at controlling agricultural nonpoint source pollution.