In coastal aquifer settings, safe yield pumping rates for supply wells located within a fresh wat... more In coastal aquifer settings, safe yield pumping rates for supply wells located within a fresh water lens must be set to rates that prevent salt water upconing and saline intrusion into the well field. Groundwater modeling to establish safe yield rates requires estimates of aquifer geometry and properties (e.g. horizontal and vertical hydraulic conductivity, porosity, dispersivity, and salt water transition
Coastal communities often rely on groundwater resources for water supply. Ensuring a safe and ade... more Coastal communities often rely on groundwater resources for water supply. Ensuring a safe and adequate supply requires a balance that meets community demands while preventing deleterious hydrologic and environmental impacts. In coastal aquifer settings where supply wells are in proximity to a salt water front (lateral encroachment of a salt water wedge or vertical upconing of an underlying salt water interface) a determination of safe yield must account for the potential for groundwater withdrawals to introduce saline water into the well field, resulting in unacceptable water quality in the short term and a fouling of the aquifer near the well field for a longer period of time. In this paper we examine factors affecting the safe yield of a well pumping above the salt water transition zone in a fresh water lens aquifer similar to those found on Cape Cod, Massachusetts. We begin with a discussion of traditional methods for determining safe yield and compare these preliminary estimates with the more refined and restrictive estimates produced using a sophisticated density-dependent salt water flow model. A simple example demonstrates that proper consideration of potential salinity impacts for a typical supply well may decrease the feasible safe yield by 30 percent or more. Acknowledgments The authors wish to thank Mark White of Environmental Partners Group and Andrew Miller of Head First for many hours of discussions that have helped to improve this paper.
In order to analyze pumping test data in a fresh water aquifer with a laterally encroaching or un... more In order to analyze pumping test data in a fresh water aquifer with a laterally encroaching or underlying salt water zone, methods typically employed for fresh water aquifers may not produce accurate estimates of aquifer parameters because they fail to account for the change in aquifer geometry and distribution of heads caused by movement of the salt water interface in
In coastal aquifer settings, safe yield pumping rates for supply wells located within a fresh wat... more In coastal aquifer settings, safe yield pumping rates for supply wells located within a fresh water lens must be set to rates that prevent salt water upconing and saline intrusion into the well field. Groundwater modeling to establish safe yield rates requires estimates of aquifer geometry and properties (e.g. horizontal and vertical hydraulic conductivity, porosity, dispersivity, and salt water transition
Coastal communities often rely on groundwater resources for water supply. Ensuring a safe and ade... more Coastal communities often rely on groundwater resources for water supply. Ensuring a safe and adequate supply requires a balance that meets community demands while preventing deleterious hydrologic and environmental impacts. In coastal aquifer settings where supply wells are in proximity to a salt water front (lateral encroachment of a salt water wedge or vertical upconing of an underlying salt water interface) a determination of safe yield must account for the potential for groundwater withdrawals to introduce saline water into the well field, resulting in unacceptable water quality in the short term and a fouling of the aquifer near the well field for a longer period of time. In this paper we examine factors affecting the safe yield of a well pumping above the salt water transition zone in a fresh water lens aquifer similar to those found on Cape Cod, Massachusetts. We begin with a discussion of traditional methods for determining safe yield and compare these preliminary estimates with the more refined and restrictive estimates produced using a sophisticated density-dependent salt water flow model. A simple example demonstrates that proper consideration of potential salinity impacts for a typical supply well may decrease the feasible safe yield by 30 percent or more. Acknowledgments The authors wish to thank Mark White of Environmental Partners Group and Andrew Miller of Head First for many hours of discussions that have helped to improve this paper.
In order to analyze pumping test data in a fresh water aquifer with a laterally encroaching or un... more In order to analyze pumping test data in a fresh water aquifer with a laterally encroaching or underlying salt water zone, methods typically employed for fresh water aquifers may not produce accurate estimates of aquifer parameters because they fail to account for the change in aquifer geometry and distribution of heads caused by movement of the salt water interface in
Uploads