bequest value (BV)—

a willingness to pay to preserve the environment for the benefit of one's descendants.

buffer value—

the difference between the maximum value of a stock of ground water under uncertainty and its maximum value under certainty where the supply of surface water is stabilized at its mean. Thus, this value arises from the ability of ground water to provide supplemental water supplies during short-term periods of drought or other supply disruptions.


cone of depression—

a localized depression of the water level in an aquifer as a result of pumping. The depression may be confined to a small area or spread over a large area depending on the pumping rate and transmissivity of the aquifer. See Figure 2.4.

confined aquifer—

an aquifer bounded above and below by units of distinctly lower hydraulic conductivity and in which the pore water pressure is greater than atmospheric pressure. An unconfined aquifer is not bounded above and is the uppermost aquifer. See Figure 2.2.

consumptive use—

a use of water that does not return water (polluted or not) to system. For example, drinking water is consumed, while shower water returns to the treatment system.

contingent valuation method (CVM)—

a method determining money measures of change in welfare by describing a hypothetical situation to respondents and eliciting how much they would be willing to pay either to obtain or to avoid a situation. Although well accepted for use values, CVM has many limitations when used to calculate nonuse values (Young, 1996).

costs—

the mirror image of benefits, that is, what is lost when a resource increases or decreases in quantity or quality. In this context one can think of costs as damages. Costs also refer to the value of any resources used to change the quality or quantity of the resource stock, for example, the costs of ground water remediation.


direct approaches—

valuation approaches that use survey-based techniques to elicit preferences for nonmarket goods and services (e.g., the contingent valuation method).

discounting—

a procedure that adjusts for future values of a particular good by accounting for time preferences. It aims to determine the present value of benefits or costs in relation to the benefits or costs at different times in the future.

drawdown—

lowering of the water table or potentiometric surface as a result of pumping.


existence value (EV)—

a pure nonuse value that is the amount an individual would pay to know that a resource exists.

extractive value—

a value calculated by adding up the benefits (across time) of removing water from an aquifer.



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