Modeling Impacts to Agricultural Revenue and Government Service Costs from Urban Growth

Urban expansion in rural areas may impact agricultural revenues and the burden of service provision on local governments. Spatially explicit urban growth models shed light on the consequences of such land use decisions. The San Joaquin Valley, an important agricultural region of California, will double in population by 2050. Using this region as an example, we modeled the spatial patterns of urban growth under seven policy scenarios and calculated potential loss of annual agricultural revenue from each. We also measured the distance from existing urban areas to new development in order to develop scenario-specific indicators of the cost to local governments for providing urban services such as sewer, water, roads, police and fire protection.As with all modeling exercises, an understanding of the strengths and weaknesses of the model being applied is essential for interpretation. The modeling applied here is not a full economic mode, but instead applies simple processes using frequently available data to estimate the farmgate revenue lost to agricultural land conversion and to represent service costs. Crop replacement, relocation, and the conversion of unfarmed lands to cropland, among other factors, are not considered. Other effects either positive or negative that may result from the growth patterns have not been analyzed.The unconstrained growth scenario (Status Quo) consumed the most land and had the greatest impact on agricultural revenue. Compact development had the least impact on agricultural revenue and the shortest distances to new development. Other forms of agricultural land protection and growth management scenarios fell short of the agricultural revenue savings and service cost reductions provided by compact development.