A PRACTICAL METHOD FOR ESTIMATING THE IMPACT OF LAND-USE CHANGE ON SURFACE RUNOFF, GROUNDWATER RECHARGE AND WETLAND HYDROLOGY

Environmental scientists and local planners need a way to estimate ini tially the impacts of land-use change on groundwater recharge, water s upply and wetland hydrology. Using a core component of more complex mo dels, a simple spreadsheet analysis can estimate the change in runoff and recharge from past or proposed land-use changes. This day-to-day t ool for planners uses only readily available data. In a sample analysi s, conversion of woodland to high-density residential and commercial u ses causes an eleven- to nineteen-fold increase in run-off volumes, an d loss of 11 to 100 percent of the natural groundwater recharge. A sur vey of planners found enthusiasm for the model. Potential applications are plan review, raising community awareness of potential problems an d support for regulatory action, and as part of local guidelines to mi nimize disturbance of the hydrologic regime.