OpenET is partnering with the California Department of Water Resources (CA DWR) to provide consistent, science-based evapotranspiration (ET) data to state agencies, Groundwater Sustainability Agencies (GSAs), and other local entities. This collaboration strengthens water management and Sustainable Groundwater Management Act (SGMA) implementation by making reliable, cost-effective ET data widely accessible. Through this contract, GSAs and their designated consultants receive free expanded access to ET data via a California-specific API, along with support from the OpenET team on data use and integration.
Accurate consumptive use data are essential for groundwater management, water budgeting, and long-term planning. OpenET offers a transparent and cost-effective approach by providing consistent ET data across California’s landscapes, which can be directly integrated into groundwater sustainability plans, water budgets, groundwater models, and accounting frameworks. Many GSAs and water users rely on OpenET within water accounting platforms to track and manage water budgets at the field or management-area scale. Beyond day-to-day management, OpenET supports long-range planning by helping agencies evaluate water demand, consumption patterns, and the trade-offs associated with various conservation practices, including infrastructure investments, on-farm efficiency improvements, and land-use transitions.
Across the state, OpenET is being used in several notable applications. In Merced County, the Merced Irrigation District and Merced Irrigation–Urban GSA use OpenET within the Groundwater Accounting Platform to provide growers and managers with a clearer understanding of consumptive use. In the Sacramento–San Joaquin Delta, the Central Delta Water Agency and South Delta Water Agency use OpenET through the Alternative Compliance Program to improve water use reporting and support more transparent, consistent data practices.
