Fundamentals of the Capture Zone Calculations to Qualitatively Protect Cities Drinking Water Wells

This study is an attempt to introduce scientific fundamentals and available methods for wellhead protection area (capture zone) delineation for drinking water wells in cities. The results of this study could obviate some demands of the national water and wastewater company in quality control of the drinking water resources by delineation and application of the wellhead protection areas. For this purpose, the available literaturer reviewed to extract, criteria and methods of wellhead protection delineation, Then, (1) fixed radius method, (2) simplified variable shape methods, and (3) flow-transport analytical methods implemented in the computer code WHPA are introduced. The applicability of these methods is shown by some sample calculations for Urmia drinking water wells. Samples of the calculated wellhead protection areas for 36 wells in Urmia City will be shown using three analytical modules in WHPA. The effects of the hydrogeologic parameters on the wellhead areas will be discussed. When reliable hydrogeologic parameters are available in the region where wells are located, the analytical methods and WHPA code produce accurate results for wellhead protection areas.