Evaluation of Water-Supply Issues Completed
The NJ Coastal Plain RASA (Regional Aquifer System Analysis) model (in this document referred to simply as “the RASA model”) is one of the most widely used models by hydrologists in the NJWSC. This model was developed as part of the RASA program, which was started in 1978 after a congressional mandate to develop quantitative appraisals of the major groundwater systems of the United States.
The RASA model, as well as other models, has been instrumental in providing valuable information regarding allocation permits and water supply. For example, the NJDEP often is interested in the sources of water to potential public supply wells under different withdrawal conditions for pending water allocation permits. Simulations using the RASA model have provided a detailed understanding of groundwater flow and sources of water to wells in the Wenonah-Mount Laurel aquifer in and around the Deptford Township, Gloucester County (Watt and Voronin, 2006). A pie chart of the simulated sources of water to inactive withdrawal wells in the Wenonah-Mount Laurel aquifer is shown in figure 2. For this study, a flow budget from the RASA model provided water-supply managers with data to make informed decisions with regards to increased withdrawals from this aquifer.
Scenarios run using the RASA model also address concerns with increased withdrawals in the Potomac-Raritan-Magothy aquifer related to new housing developments in Woolwich Township, Gloucester County (Lois M. Voronin, U.S. Geological Survey, oral commun., 2006). The Picatinny model was used to provide information regarding a potential public-supply well installation near Picatinny Arsenal within the model boundary. The RASA model in conjunction with two other models—the Cape May-Atlantic County and New Jersey Coastal Plain Sharp models--address questions posed regarding eight new allocation permits within the 800-ft Sand Aquifer in Atlantic County. These models were used to simulate changes in water levels, identify the source supplying the increased groundwater flow, and quantify the effects on saltwater movement towards production wells in Cape May County as a result of the proposed increased withdrawals at proposed or existing wells (Pope, 2006). Simulated potentiometric surfaces and pathlines from the 250-milligram per liter isochlor under different withdrawal conditions using the Cape May Atlantic City model is shown in figure 3. The table indicates the times of travel for particles from the 250-milligram per liter isochlor to production wells tapping the Atlantic City 800-ft Sand.
The RASA model also was used to provide information to the NJDEP for the Water Supply Master Plan. Scenarios were run that evaluated the effects of increased withdrawals on water levels and water budgets within planning areas based on future population estimates (Gordon, 2007). Water managers incorporated this data into the State planning document. Simulations of groundwater flow from models provide valuable information that has helped shape the decisions of the water managers.
The NJDEP Well Head Protection program provides a regulatory framework for the evaluation and control of potential sources of contamination of public-supply wells. A critical element of such evaluations is the delineation of contributing areas for all public and non-community water supply wells in New Jersey. NJDEP allows for contributing areas to be delineated using a groundwater flow model in complex hydrogeologic settings (Pope and Watt, 2005). A version of the archived groundwater flow model developed by the USGS in the Pennsauken Township area, Camden County was used to delineate contributing areas to the Puchack well field. The contributing areas to this major well field, shown in figure 4, was determined by using particle-tracking analysis that calculates the travel times of water to wells (Pope and Watt, 2005). The Lamington model, in southwestern Morris County, also was used to determine groundwater flow patterns and areas contributing recharge to wells and streams under different withdrawal conditions for Randolph Township (Nicholson and Watt, 1998), as well as, for Morris County Municipal Utilities Authorities.
Other models have been used to address different hydrologic issues such as saltwater intrusion or base-flow depletion. The Camden model was used to evaluate the vulnerability of production wells in the Potomac-Raritan-Magothy aquifer to saltwater intrusion from the Delaware River in Camden, Salem, and Gloucester Counties under different drought conditions (Navoy and others, 2005). Particle tracking was used to delineate the contributing area for the production wells and determine time-of-travel for saltwater intrusion. Several of the archived models describe and characterize the unconfined aquifer system and its interaction with the surface-water system in response to increased withdrawals. The Upper Maurice River basin model and Toms River-Metedeconk River model are two examples. Both of these models evaluated predevelopment, recent, and future withdrawal conditions and their relation to base-flow depletion.
The NJ Coastal Plain RASA (Regional Aquifer System Analysis) model (in this document referred to simply as “the RASA model”) is one of the most widely used models by hydrologists in the NJWSC. This model was developed as part of the RASA program, which was started in 1978 after a congressional mandate to develop quantitative appraisals of the major groundwater systems of the United States.
The RASA model, as well as other models, has been instrumental in providing valuable information regarding allocation permits and water supply. For example, the NJDEP often is interested in the sources of water to potential public supply wells under different withdrawal conditions for pending water allocation permits. Simulations using the RASA model have provided a detailed understanding of groundwater flow and sources of water to wells in the Wenonah-Mount Laurel aquifer in and around the Deptford Township, Gloucester County (Watt and Voronin, 2006). A pie chart of the simulated sources of water to inactive withdrawal wells in the Wenonah-Mount Laurel aquifer is shown in figure 2. For this study, a flow budget from the RASA model provided water-supply managers with data to make informed decisions with regards to increased withdrawals from this aquifer.
Scenarios run using the RASA model also address concerns with increased withdrawals in the Potomac-Raritan-Magothy aquifer related to new housing developments in Woolwich Township, Gloucester County (Lois M. Voronin, U.S. Geological Survey, oral commun., 2006). The Picatinny model was used to provide information regarding a potential public-supply well installation near Picatinny Arsenal within the model boundary. The RASA model in conjunction with two other models—the Cape May-Atlantic County and New Jersey Coastal Plain Sharp models--address questions posed regarding eight new allocation permits within the 800-ft Sand Aquifer in Atlantic County. These models were used to simulate changes in water levels, identify the source supplying the increased groundwater flow, and quantify the effects on saltwater movement towards production wells in Cape May County as a result of the proposed increased withdrawals at proposed or existing wells (Pope, 2006). Simulated potentiometric surfaces and pathlines from the 250-milligram per liter isochlor under different withdrawal conditions using the Cape May Atlantic City model is shown in figure 3. The table indicates the times of travel for particles from the 250-milligram per liter isochlor to production wells tapping the Atlantic City 800-ft Sand.
The RASA model also was used to provide information to the NJDEP for the Water Supply Master Plan. Scenarios were run that evaluated the effects of increased withdrawals on water levels and water budgets within planning areas based on future population estimates (Gordon, 2007). Water managers incorporated this data into the State planning document. Simulations of groundwater flow from models provide valuable information that has helped shape the decisions of the water managers.
The NJDEP Well Head Protection program provides a regulatory framework for the evaluation and control of potential sources of contamination of public-supply wells. A critical element of such evaluations is the delineation of contributing areas for all public and non-community water supply wells in New Jersey. NJDEP allows for contributing areas to be delineated using a groundwater flow model in complex hydrogeologic settings (Pope and Watt, 2005). A version of the archived groundwater flow model developed by the USGS in the Pennsauken Township area, Camden County was used to delineate contributing areas to the Puchack well field. The contributing areas to this major well field, shown in figure 4, was determined by using particle-tracking analysis that calculates the travel times of water to wells (Pope and Watt, 2005). The Lamington model, in southwestern Morris County, also was used to determine groundwater flow patterns and areas contributing recharge to wells and streams under different withdrawal conditions for Randolph Township (Nicholson and Watt, 1998), as well as, for Morris County Municipal Utilities Authorities.
Other models have been used to address different hydrologic issues such as saltwater intrusion or base-flow depletion. The Camden model was used to evaluate the vulnerability of production wells in the Potomac-Raritan-Magothy aquifer to saltwater intrusion from the Delaware River in Camden, Salem, and Gloucester Counties under different drought conditions (Navoy and others, 2005). Particle tracking was used to delineate the contributing area for the production wells and determine time-of-travel for saltwater intrusion. Several of the archived models describe and characterize the unconfined aquifer system and its interaction with the surface-water system in response to increased withdrawals. The Upper Maurice River basin model and Toms River-Metedeconk River model are two examples. Both of these models evaluated predevelopment, recent, and future withdrawal conditions and their relation to base-flow depletion.