Since that time, water quality in the Occoquan Reservoir has steadily improved and the reliable, high-quality effluent produced by UOSA has increased the safe yield of the Reservoir.
In this case, prudence is called the "safe yield," which for the city's reservoirs is 1.3 billion gallons a day.
The demand now exceeds the safe yield of the system by 200 million to 300 million gallons a day.
In the case of groundwater there is a safe yield of water extraction per unit time, beyond which the aquifer risks the state of overdrafting or even depletion.
There is evidence in the Hanford area that depths to groundwater are increasing, indicating concern for safe yields of the Tulare Lake groundwater subbasin.
Overdrafting is the process of extracting groundwater beyond the safe yield or equilibrium yield of the aquifer.
The Wanaque is intended to supply its customer load of 2.2 million people 173 million gallons of water a day, an amount known in the world of reservoir management as "safe yield."
As a result, the reservoir's safe yield is more like 94 million gallons a day.
Salvatore A. Celona, director of the Westchester County Water Agency, told the forum that this system was providing a "safe yield" below current demand for the region.
The safe yield of the aquifer is estimated at between 2 and 2.5 billion cubic meter per year, depending on rainfall.