Impacts of Alternative Climatic Conceptualizations on Ground Water Planning Process in Texas

Groundwater management in Texas is largely based on the concept of local control and carried out by Groundwater conservation districts (GCDs).  GCDs typically are defined on a county basis and there are several GCDs within an aquifer sub-division.  The state is also divided into 16 groundwater management areas (GMA) and the districts within each GMA must participate in a joint planning process to define the future conditions of the aquifer over a 50 year planning horizon.  The Texas Water Development Board has developed several regional-scale groundwater flow models (GAMs) to help facilitate groundwater planning.  These models are used in to help evaluate different desired future conditions and eventually estimate available groundwater.  Representing future climatic conditions, especially recharge is noted to be a contentious issue during the joint planning process in many GMAs.  Conservation-oriented stakeholders tend to emphasize the use of drought-of-record type conditions to obtain estimate of future availability, while economically-oriented stakeholders prefer more optimistic scenarios with periods of high rainfall and recharge.  Addressing the extent to which assumed future climatic conditions impact water availability estimates is an important step towards developing stakeholder driven participatory groundwater management approaches envisioned by the Texas legislature.  The goal of the present study is to utilize fuzzy set theoretic approaches to evaluate the impacts of alternative climatic conceptualizations on the groundwater planning process in Texas.  Illustrative case-study for the developed methodology will be presented.