Office of the Delta Watermaster

Delta Measurement Experimentation Consortium (DMEC)

Summary

The Delta Measurement Experimental Consortium (DMEC) was formed in 2016 by the Office of the Delta Water Master in response to passage of Senate Bill 88 which requires all California water rights holders to report their water usage. The objective of the DMEC is to engage all interested parties to assess methods for water diversion, measurement, and reporting within the Sacramento-San Joaquin legal Delta. Due to unique hydrologic characteristics of subsided islands and the predominant use of siphon pumps for irrigation across the Delta, traditional methods of measurement including conventional gages confront substantial technical, feasibility and reliability challenges.

The DMEC meets quarterly to discuss measurement technologies and methods, water measurement experiments, and software tools that can be applied in the Delta across a range of different water diversion equipment designs and operating conditions.

The DMEC has played a foundational role in assessing the effectiveness and reliability of multiple water measurement approaches. Since 2021, based on the information developed by the group and general consensus regarding the efficacy and cost-feasibility of various techniques, roughly 70% of water users in the Delta are now participating in “alternative compliance plans” (ACPs) using OpenET, an open-source remote sensing measurement of evapotranspiration as a reliable, feasible, and transparent methodology to measure consumptive use of water in the legal Delta.

The DMEC will continue to evaluate new information, experimental outcomes, and stakeholder recommendations to improve the accuracy, timeliness, and accessibility of date to better understand real-time consumptive use in the Delta. The DMEC process and its meetings will highlight ongoing work to inform and to improve water measurement and reporting data to inform water management actions consistent with rights.