Status of the Cosumnes Groundwater Subbasin 7/27

Thursday, July 27, 2023

Presentation/Discussion of the Status of the Cosumnes Groundwater Subbasin and Related Matters 6:10 – 7:10 by Austin Miller, Sloughhouse RCD Executive Director

The ECOS Water Committee invites you to join us in a presentation/discussion of the sustainability of the Cosumnes Groundwater Subbasin (CGA). This subbasin is the source of groundwater providing a significant amount of the water used by agriculture, rural residents, and small urban areas in the south county and western portions of Amador County that are located south of the Cosumnes River.

Austin Miller, Executive Director of the Sloughhouse RCD coordinates the management of the subbasin and will present the latest condition of the subbasin as reflected in the annual subbasin sustainability report recently submitted to the state. Austin will also brief us on interactions with the other subbasin GSAs, neighboring subbasins, and the Regional Water Authority on the development of a Regional Water Bank. Finally, Austin will discuss the ability of the Cosumnes Subbasin Groundwater Sustainability Agencies to implement the Subbasin’s Groundwater Sustainability Plan (GSP) given the loss of grant funds and other limitations and what is planned to deal with these impediments. The effective implementation of the GSP is made more important given plans by local water purveyors to expand conjunctive use, the Regional Water Authority’s plan to operate a Regional Water Bank in the North and South American Subbasins, and the potential impacts these activities may have on the sustainability of the Cosumnes Subbasin. Bring your questions and be prepared for a thoughtful presentation and discussion.

Link to join: https://us02web.zoom.us/j/6656164155
To phone in: 669-900-6833, Meeting ID: 665 616 4155

Click here to view the full meeting agenda.

Sustainability of the South American groundwater subbasin 6/28

The ECOS Water Committee invites you to join us on June 28 from 6:00 until 7:00 to take part in a presentation/discussion of the sustainability of the South American groundwater subbasin. This subbasin is the source of groundwater providing a significant amount of the water used by the urban areas and agricultural areas south of the American River. John Woodling, Executive Director of the Sacramento Central Groundwater Authority (SCGA), the agency that coordinates and manages a major portion of the subbasin, will be presenting the latest condition of the subbasin as reflected in the annual subbasin sustainability report recently submitted to the state. He will also describe efforts to protect Groundwater Dependent Ecosystems, shallow wells, and improve the subbasin’s monitoring and modeling programs. All of these actions are important given the plan by the Regional Water Authority to operate a water bank in the area overseen by SCGA. We are all interested to learn how SCGA plans to interact with the proposed Regional Water Bank. Bring your questions and be prepared for a thoughtful presentation and discussion.

Link to join: https://us02web.zoom.us/j/6656164155
To phone in: 669-900-6833, Meeting ID: 665 616 4155

Comments regarding sufficiency of South American Groundwater Sustainability Plan

April 15, 2022

Here is a summary of our comments:
1) We find the climate change analysis used as the basis for the GSP is not sufficiently robust to reflect currently anticipated climate change conditions for the region. The analysis does not reflect current science. For this reason, we suggest DWR provide more direction in this area for future GSP updates.
2) We believe a review of the GSP utilizing Article 6, Section 355.4 finds the plan deficient in several important areas. Our findings are listed in more detail below. DWR should work with the subbasin GSAs to address the shortcomings described below before approving the GSP.

Click here to read the letter in full.

Regional Groundwater Sustainability – The Plans are Finished so what’s Next?

Over the past several years local Groundwater Sustainability Agencies (GSAs) charged with managing the region’s groundwater have been assessing the condition of the region’s groundwater resources and developing monitoring systems and management plans and projects to maintain the sustainability of these resources for the foreseeable future. These efforts have resulted in the completion of three Groundwater Sustainability Plans (GSPs) that cover each of the region’s groundwater subbasins – North American Subbasin, South American Subbasin, and Cosumnes Subbasin. The GSPs respond to State required planning criteria outlined in the 2014 Sustainable Groundwater Management Act (SGMA). The California Department of Water Resources webpage has information about SGMA, the GSP planning process, and a public portal containing the three GSPs for the Sacramento region.  

ECOS, through the Water Committee, has participated in the development of these GSPs by attending public meetings and workshops, and providing comments on the draft plans. We have condensed these comments into a matrix comparing comments for each of the three GSPs. The matrix contains a summary of each original comment and, in bold, the actions taken by the GSAs to address each comment as documented in the final adopted GSPs. The full text of each ECOS comment letter can be found on the ECOS web site.

While some comments have been addressed in the final plans, others were not. For example, key aspects of the GSPs are six sustainability indicators that establish thresholds for when management actions must be taken to assure continued subbasin sustainability. The North American Subbasin GSP calls for management actions to be taken after one year of one or more of the GSP sustainability indicators exceeding action levels thus indicating the subbasin is in trouble. Unfortunately, the South American Subbasin allows three years of indicator exceedance that may lead to no actions being taken until the fourth year of an indicator being exceeded. The Cosumnes Subbasin did adjust their corresponding exceedance time periods but still allow a problem to exceed one or more threshold criteria for at least two years before actions to remedy the situation are taken. ECOS has argued that a one year exceedance criteria is acceptable and should be utilized in all three GSPs.

ECOS also believes climate change is not effectively addressed in the plans. All three GSPs base their management actions on a climate scenario that seems less realistic than current climate experience and the latest climate science indicates. This errant planning assumption may significantly overestimate the amount of groundwater available to meet demands in the future. If not corrected, sustainable management of the subbasins may be very difficult within the next decade.

ECOS members are meeting with the local GSA representatives to explore options to address our concerns prior to the next GSP updates which are due in 2025. Depending on the outcome of these meetings ECOS may find it necessary to participate in the State’s GSP public comment process.

Click here to view the matrix.