State determines Paso Robles groundwater basin plan is ‘incomplete.’ Here’s what that means
The California Department of Water Resources determined that San Luis Obispo County’s groundwater sustainability plan for the Paso Robles basin was “incomplete,” according to a letter sent to the county Jan. 21.
The county acknowledged the deficiencies and said it will make the necessary improvements in the plan by the six-month deadline of July 20.
Work on the improvements to the plan had already begun in June when the county received initial indication from the state that the plan did not meet its standards regulated under the Sustainable Groundwater Management Act (SGMA, pronounced “sigma”).
“The work in addressing the deficiencies is nearing completion and we are confident that the issues raised will be resolved well before the July 20 deadline for submittal of an updated GSP (groundwater sustainability plan),” said Blaine Reely, the groundwater sustainability director for the county. Reely’s is a new position created in November.
The Paso Robles groundwater sustainability plan is a 1,100-page document that outlines actions the entities that manage the basin — the county, Shandon-San Juan Water District, city of Paso Robles and San Miguel Community Services District — will take to balance the needs of groundwater users in the area with the water available.
The plan was adopted and submitted to the state in January 2020. It was required under SGMA because the basin is designated as “a high priority basin subject to critical conditions of overdraft,” meaning more water has been withdrawn in recent decades than what is sustainable.
Thousands of users tap into the basin for water including municipalities, residents, wineries, vineyards and other agricultural operations in the northern San Luis Obispo County area.
Generally, the plan outlines how the management entities will promote water conservation measures for all users of the groundwater, as well as mandatory pumping limitations for those who live in areas where the groundwater is especially low. It also explains how the basin will be managed and monitored to ensure there is enough water available for future generations.
The state was required to “evaluate whether a submitted groundwater sustainability plan conforms to specific requirements of the Sustainable Groundwater Management Act (SGMA), is likely to achieve the sustainability goal for the basin covered by the plan and whether the plan adversely affects the ability of an adjacent basin to implement its GSP or impedes achievement of sustainability goals in an adjacent basin,” according to a state water resources department staff report sent to the Paso Robles basin agencies Jan. 21.
What was missing from Paso Robles basin plan?
Two main deficiencies were identified in the Paso Robles basin plan.
The first is that the plan did not adequately assess the adverse impacts to residents with wells should the groundwater level dip to a certain level.
The plan does not describe how the managing entities “determined that significant and unreasonable depletion of supply will be avoided” given the “chronic lowering of groundwater levels,” the state report says.
In other words, the managing entities must establish better thresholds for how low the groundwater levels can reach before it’s considered undesirable for domestic well users.
The second deficiency identified by the state is that the plan did not adequately address how surface water may be connected to the groundwater basin’s supply and whether the overpumping of the basin was depleting the surface water.
Surface water sources in the Paso Robles basin area consist of the Salinas and Estrella rivers, and the Huer Huero and San Juan creeks.
Should the county determine there is a link between depletion of the surface water sources and the groundwater basin, it must then find mitigation strategies to avoid such depletion.
Reely said revisions to the plan are well underway and expects to have them to the state well before the July 20 deadline.
