Author(s)

S. J. Meyland

Abstract

When determining how much water can safely be withdrawn from an aquifer system, the concept of \“safe yield” has been used. This term has come to mean if annual withdrawals do not exceed the annual rate of recharge, then the withdrawals are within a safe level of extraction. However, this approach has been shown to be an oversimplification of aquifer dynamics. It is flawed for it fails to incorporate other processes occurring in an aquifer as water is pumped from the system. A new approach is suggested that adds a safety margin to the assessment of the production capacity of an aquifer. This approach is defined as \“managed yield” and it is recommended as a replacement for safe yield when developing management strategies for groundwater systems. Keywords: groundwater flow, groundwater, groundwater management, groundwater depletion, safe yield, sustainable yield, managed yield, water budget, water supply, water sustainability. 1 Introduction National Geographic Magazine’s special issue on water described the world’s present water situation as follows: \“Nearly 70 percent of the World’s freshwater is locked in ice. Most of the rest is in aquifers that we’re draining much more quickly than the natural recharge rate. Two-thirds of our water is used to grow food. With 83 million more people on the earth each year, water demand will keep going up unless we change how we use it” [1].

Keywords

groundwater flow, groundwater, groundwater management, groundwater depletion, safe yield, sustainable yield, managed yield, water budget, water supply, water sustainability