Harvey, Dougall James Miln2006-07-282006-07-2819991999http://hdl.handle.net/10012/445Groundwater protection has become an important component of regional planning and engineering as a result of the large risk that is associated with the contamination of groundwater aquifers, their values as a resource to society and the high cost associated with remediation. One of the methods that has been proposed for the protection of regional groundwater aquifers is to zone a boundary around current production wells as a groundwater conservancy area in order to restrict risky industrial practises within the hydrogeologic environment from which public water supply wells draw their groundwater. The USEPA has detailed a methodology for generating the boundary around a production well and designated the area within this boundary as a wellhead protection area (WHPA). However, all of the methods that are currently consider acceptable for WHPA delineation do not necessarily provide the best alternative for determining the WHPA boundary when approached from a benefit-cost-risk perspective. The risk associated with WHPA delineation is related to the improper zoning of land that is not necessary for groundwater protection under the criteria and constraints set out in the Wellhead Protection Plan. The present research developed a Wellhead Protection (WHP) Plan for the community of Pleasant Plains, New Jersey using information from State WHP plans that have submitted to the USEPA for approval. The Pleasant Plains WHP Plan sets out the criteria and constraints that are necessary for WHPA delineation at the municipal wellfields, and will be used as a basis for determining the best methodology for WHPA delineation. The delineation methods that were compared include arbitrary and calculated fixed radii, analytical methods, analytical and numerical models as detailed by the USEPA, as well as random walk numerical modeling. The research compared these methodologies to determine the best alternative for WHPA delineation, and the regret associated with not using the most scientifically defensible method of delineating groundwater protection areas. The results indicate that the best alternative for generating wellhead protection areas is based on numerical modeling that includes the affects of both advection and dispersion. The results also show that there is a reduction in risk associated with being closer to the "true" WHPA boundary based on the constraints set out in the WHP Plan. Uncertainty analysis was then performed on the numerical WHPA models to determine the value of information associated with the uncertainty in the put parameters of the conceptual model of the groundwater environment around the study site. This value of information represents the maximum exploration and sampling budget that should be put toward obtaining new data to reduce input uncertainty to the numerical model for delineating WHPA boundaries. Finally, the transient nature of hydrologic stresses on the groundwater flow field was investigated to determine their effect on the WHPA boundaries. These transient effects include changes to the pumping rates for existing wells, the addition of new wells to the wellfield, and the decommissioning of contaminated wells in an existing wellfield. The results show that the best option for WHPA delineation uses sustainable well rates to reduce the effects of changing pumping rates, that new wells having an effect on existing WHPA boundaries must be analysed using the same methods that were used to generate the existing boundaries, and that the decommissioning of existing well should not be used to change existing boundaries.application/pdf8132147 bytesapplication/pdfenCopyright: 1999, Harvey, Dougall James Miln. All rights reserved.Harvested from Collections CanadaDoctoral Thesis