Protection Areas

What Are Wellhead Protection Areas?


Wellhead Protection Areas are the lands surrounding our water supply wells vital to the protection of our drinking water. Rainwater and snow melt provide water to replenish the aquifer that feeds our wells. If this water carries contaminants that are not filtered out by the native sands and gravels lying between the ground surface and the aquifer, then the aquifer can become contaminated. Kennewick Wellhead Protection Areas were determined by a computer modelling program, which calculated the areas based on the time that water with potential contaminants takes to get to the City's wells.

This map represents the Kennewick Wellhead Protection Areas for Ranney Collector Numbers 4 and 5. As shown, five areas with increasing Times of Travel are delineated. They range from 180 days to ten years with a buffer zone. In actual groundwater systems, contaminants may move at different rates than the groundwater depending on the specific characteristics of the contaminant. Typically, contaminants move at rates much slower than the groundwater flow rate. Contaminants released at the ground surface also travel vertically, which may take longer to reach the actual groundwater depth. It is highly unlikely that potential contaminant sources located outside of this map could cause a water quality impact at the Ranney Collectors.