Impacts of Development in El Dorado County

By Greg Greenwood and Shawn Saving

For more information please contact:
Robin Marose
Fire and Resource Assessment Program
California Department of Forestry and Fire Protection
PO Box 944246, Sacramento, CA 94244
(916) 327-3939 FAX (916) 327-1180
robin.marose@fire.ca.gov

Full Report (pdf document)

Abstract

We modeled future development in El Dorado County, California, a rapidly developing rural region of the Central Sierra Nevada Mountains, to assess ecological impacts of expanding urbanization and effectiveness of standard policy mitigation efforts. Using 1990 Hardwood Rangelands pixel data and county parcel data, we constructed a footprint of current development and simulated future development using a modified stochastic flood-fill algorithm. Incorporated into our model are constraints to development from the General Plan (high slope, stream buffers, and oak retention) and the parcel data (public ownership and easements, and existing development). To evaluate policy options facing the County Board of Supervisors, we altered these constraints in likely combinations such as wider stream buffers, set aside ordinances, regional clustering, and acquisition programs. The model overlaid development outcomes for each scenario onto the vegetation data and calculated metrics of habitat loss and fragmentation for all cover types (wildland) and for oak hardwood types only. Policy alternatives ranging from existing prescriptions to very restrictive regulations had marginal impact on mitigating habitat loss and fragmentation. Historic land parcelization limits effective mitigation of development impacts by general plan prescriptions that apply only when a parcel requires subdivision before development (current policy). Options such as county-wide ordinances or downzoning were more effective in preserving habitat and connectivity, but may not offer enough extra protection to offset the large investments of 'political capital' required for implementation. The natural latticework-like distribution of hardwoods in the region also contributes to this ineffectiveness as even low densities of development can cause significant fragmentation. Custom, parcel based acquisition scenarios minimized habitat loss and maximized connectivity. Better analysis and review of public policy and planning design may be a more effective 'smart growth' tool to minimize negative impacts of development than generic policy prescriptions.

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