The Use of System Dynamics Model to Enhance Integrated Resources Planning Implementation

Elsinore Valley Municipal Water District (EVMWD), like many other water agencies in southern California, relies heavily on imported water supply. The uncertainty associated with reliable imported water supplies due to drought conditions and climate change, and the increasing cost of imported water are areas of concern for EVMWD. Considering these conditions, EVMWD, which serves one of the fastest growing regions within Riverside County, embarked upon the development of its first Integrated Resources Plan (IRP) – a long term strategy for providing reliable water supplies to its growing customer base. The IRP’s evaluation methodology consists of three steps: Identification of potential water supply projects, project evaluation, and recommendation of a water supply portfolio comprised of the specific projects. A System Dynamics (SD) Water Resources Decision Support System (WRDSS) was used to evaluate different scenarios and examine EVMWD’s vulnerability to risks such as water supply shortage, and changes to water quality and/or water demand projections. Even though SD has been extensively applied to many water resources planning modeling efforts, based on our literature review, there is not a documented case of SD modeling applied to an IRP project. The recommended water supply portfolio represents the most cost effective option. It meets the forecasted long term deficit and provides the best reliability while providing good quality water supplies to EVMWD’s customers. The recommended water supply portfolio will be implemented using an adaptive management approach to adjust to changing conditions, coupled with long-range resource management policies that optimize water supply and storage assets in times of both drought and surplus.