Groundwater Management utilizing a Safe Yield Range tool


Groundwater management in many countries has progressed over the latter half of the last century from virtually nil to a highly regulatory regime today. (Custodio, 2002) In this paper groundwater management refers to the planning, implementation and operation necessary to provide safe and reliable groundwater supplies as well as the sustainable development of this resource.

Utilizing the theory from both the safe yield and the sustainable yield approach, the safe yield range approach was developed. A safe yield range gives a guideline range where abstraction should be maintained to preserve the integrity of the aquifer system. It is the range between which water can be withdrawn from an aquifer system without hazardous depletion of the stored reserve and or deterioration of the water quality or causing unacceptable environmental, economic or social consequences. The lower boundary of the range is the point at which abstraction is preferred while the upper boundary of the range gives the point that abstraction should not exceed.

This approach was applied to three wellfields across Trinidad; Tucker Valley, Las Lomas and Penal. The Tucker Valley wellfield is positioned in an unconfined gravel sub aquifer system in the northwestern peninsula of the island. The Las Lomas wellfield taps into a confined sand system in the center of the island. The Penal wellfield is situated in a fully confined, fine-grained sand aquifer that is heavily faulted area. Engaging this safe yield range tool is beneficial in maintaining the quality and quantity of groundwater reserve while sanctioning groundwater abstraction to augment water supply.


Candice Santana (Water Resources Agency, WASA)