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MODULE-2 Wellhead Protection Areas
- Wellhead Protection Areas
- Wellhead Protection Area Delineation Methods
- Selecting a Wellhead Protection Area Delineation Method
Wellhead Protection Area Delineation Methods
Hydrogeologic Mapping Methods
Hydrogeologic mapping methods are loosely defined by EPA as geologic, geophysical, and dye-tracing methods that can be used to define zones of contribution. In Washington, where hydrogeologic and geologic information is often either regional in scope or non-existent, hydrogeologic mapping is often required to characterize aquifer properties, groundwater flow directions, and aquifer boundaries as a prelude to analytical numerical modeling.
Hydrogeologic mapping methods can be useful where hydrogeologic conditions preclude application of simple analytical models. Examples of settings where geologic features exert strong control over groundwater flow direction and rates are fractured rock settings (such as basalt), karst, small valley fill deposits, and irregular river or barrier boundaries. Data required include geologic maps, aquifer water level mapping, pump test data, hydrogeologic reports, and well reports. These methods require specialized expertise in geologic and geomorphic mapping, plus significant judgment on what constitutes likely flow boundaries.