Conjunctive Use

Conjunctive management is the coordinated use of available surface water and groundwater supplies to meet water demands and increase water supply reliability. The concept of conjunctive water management consists of maximizing the use of surface water during the time the supply is plentiful and saving groundwater for the periods when surface water supplies are short. Development of a conjunctive management plan is complex and includes consideration of surface water and groundwater hydrology, water demand characteristics, water quality, surface and underground storage capacities, conveyance capacity, capital and O&M costs, and agency powers.

While GEI has worked in virtually all areas of water resources engineering, development and implementation of conjunctive management programs stands out as one of the areas in which we have clearly been a leader. The company formulated a pioneering conjunctive management program for the Arvin-Edison Water Storage District, located near the southern end of California’s Central Valley. This program included the construction of $44 million (in 1960s dollars) in facilities to manage a highly variable surface water supply from the federal Central Valley Project conjunctively with groundwater. In the decades that followed, conjunctive management programs were formulated and implemented for water agencies with contracts for supplemental surface water supplies from California’s State Water Project and the Central Arizona Project.

While similar in concept, each program is unique, taking into consideration the myriad of physical and institutional differences between water agencies. Our clients have seen increased water supply reliability, reduced costs, and improved financial positions as a result of the firm’s conjunctive management planning efforts.