Groundwater Budgets

Science Center Objects

Groundwater budgets are commonly used in water-resource studies to gain a better understanding of the groundwater-flow system. The hydrologic cycle in the basin can be represented by a long-term water budget in which inflows are balances by outflows and, thus, no long-term change in storage occurs. The water budget can be evaluated through use of two internal budgets and their corresponding balance equations: one that describes the gains and losses to and from the land-surface and the other that describes gains and losses to and from the saturated unconfined groundwater system. Recharge, a variable that cannot be measured or estimated except from other hydrologic data, was determined separately in both equations, and the two values were compared. The water budget provides a basis for evaluating change and quantifying the stresses on the system. A flow budget provides water-supply managers with a detailed understanding of the groundwater flow allowing them to make informed decisions with regards to the water resources within the basin.


Summary table for water budgets completed by the Surficial Aquifer Studies

Illustration of Groundwater interactions

Illustration of Groundwater and Surface water interactions

(Public domain.)

All flow data is in inches per year.

(--, no data; *, this value is the sum of all of the individual consumptive withdrawals used in the Upper Maurice water budget; water budgets for the Toms River and Metedeconk River were calculated separately in the report. Values in parentheses under the Toms River heading are values for the Metedeconk River Basin budget)











Artificial recharge is water that pumped from the confined aquifers, used, treated, and then released in to the surface-water system, or water that was withdrawn from sources outside of the study area but released to streams within the study area. 

Artificial recharge to the groundwater system occurs where water is withdrawn from the confined aquifer, treated by septic systems, and then discharged to the unconfined groundwater system.

a-the value of Rn for the Forked River Surficial Aquifer Study ( Rng in the report) includes additional budget terms of Ri--which accounts for the groundwater inflow from adjacent surface-water basins outside of the study area—and Rns—which accounts for the natural recharge to the aquifer from precipitation.  This is necessary to account for those areas where the groundwater and surface-water divide do not coincide.