 |
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
Numerical Flow/Transport Models
WHPAs can be delineated using computer models that approximate ground water flow and/or solute transport equations numerically. These models are generally recognized as technically superior means to delineate wellhead zones of contribution, if sufficient data can be assembled. Models are generally grouped as two- and three-dimensional. Data requirements are similar to hydrogeologic mapping and analytical models. However, numerical models are able to incorporate much more of this information. A comparison of WHPA boundaries delineated using the calculated fixed radius method, an analytical model, and a numerical model was presented by EPA. Because there is wide variety in hydrogeologic settings, no set of examples should be considered typical.
Numerical models provide a very high potential degree of accuracy and can be applied to nearly all types of hydrogeologic settings. They may be very desirable in areas where there are other ongoing groundwater management programs in place. Costs for this method are relatively higher than others, and considerable technical expertise in hydrogeology and modeling is required to use this method. However, the cost may be warranted in areas where there are higher risks of contamination and a high degree of reliability is necessary.