title: Comparative study of methods for WHPA delineation.
abstract: Human activities, whether agricultural, industrial, commercial, or domestic, can contribute to ground water quality deterioration. In order to protect the ground water exploited by a production well, it is essential to develop a good knowledge of the flow system and to adequately delineate the area surrounding the well within which potential contamination sources should be managed. Many methods have been developed to delineate such a wellhead protection area (WHPA). The integration of more information on the geologic and hydrogeologic characteristics of the study area increases the precision of any given WHPA delineation method. From a practical point of view, the WHPA delineation methods allowing the simplest and least expensive integration of the available information should be favored. This paper presents a comparative study in which nine different WHPA delineation methods were applied to a well and a spring in an unconfined granular aquifer and to a well in a confined highly fractured rock aquifer. These methods range from simple approaches to complex computer models. Hydrogeological mapping and numerical modeling with MODFLOW-MODPATH were used as reference methods to respectively compare the delineation of the zone of contribution and the zone of travel obtained from the various WHPA methods. Although applied to simple ground water flow systems, these methods provided a relatively wide range of results. To allow a realistic delineation of the WHPA in aquifers of variable geometry, a WHPA delineation method should ensure a water balance and include observed or calculated regional flow characteristics.
authors.affiliation: Geological Survey of Canada, 490 rue de la Couronne, Québec, Québec, Canada G1K 9A9. dparadis@nrcan.gc.ca
authors.forename: Daniel
authors.initials: D
authors.lastname: Paradis
authors.forename: Richard
authors.initials: R
authors.lastname: Martel
authors.forename: Gilbert
authors.initials: G
authors.lastname: Karanta
authors.forename: René
authors.initials: R
authors.lastname: Lefebvre
authors.forename: Yves
authors.initials: Y
authors.lastname: Michaud
authors.forename: René
authors.initials: R
authors.lastname: Therrien
authors.forename: Miroslav
authors.initials: M
authors.lastname: Nastev
mesh_terms: D012015:Reference Standards; D014481:United States; D014484:United States Environmental Protection Agency; D014867:Water
chemical_list: D014867:Water