SLVWD Board Meeting Summary

May 12, 2021

Mark Dolson

Highlights:

  • Special Workshop on Conjunctive Use

  • Next Board meeting is at 6:30 PM on May 20.

Preliminaries:

Special Workshop on Conjunctive Use

The May 12th Board Meeting for the SLVWD was a special, purely informational meeting devoted entirely to educating the Board and the public on the District’s ongoing investigations into improving its “conjunctive use.”  Conjunctive use refers broadly to coordinating the use of both surface water and groundwater to maximize water availability while minimizing groundwater depletion and environmental harm.  With a number of groundwater basins in critical overdraft, and with the current drought conditions and predicted climate change, conjunctive use is recognized as an increasingly important aspect of water management across the state.

In 2017, the County of Santa Cruz received funding to help local agencies improve their conjunctive use.  As a result, a water use analysis for the SLVWD was initiated in 2019, and four scenarios were identified, with three deemed worthy of more detailed investigation.  The final report should be ready for the Board and public to review in the next few months, but the presentation this evening provided a preview of the three studied scenarios.

The presentation began with brief introductions by SVLWD Environmental Planner Carly Blanchard and Santa Cruz County Water Resources Planner Sierra Ryan.  Santa Cruz County Fisheries Biologist Mike Podlech then summarized the four scenarios (out of an initial list of 22) that received serious consideration.

The SLVWD normally derives about half its water from surface sources by diverting water from creeks, and the other half from groundwater pumped from wells.  Unused surface water either seeps into the ground or flows into the San Lorenzo River, which serves as a major water source for the City of Santa Cruz (and also as fish habitat).

A closer look, however, reveals that SLVWD currently consists of three distinct service areas, each with its own local water sources.  The North Area (from Boulder Creek through Ben Lomond and Lompico) derives its water from both creeks (Peavine, Clear, Sweetwater, and Foreman) and wells.  The Felton Area is supplied exclusively by local creeks (Fall, Bennett, and Bull).  Lastly, the South Area (the southern part of Scotts Valley) is supplied by groundwater drawn from the District’s Pasatiempo wells.  There are interties (i.e., pipelines) between these three service areas, but these are currently only authorized for emergency use.

The first of the three studied scenarios addressed a longstanding issue with regulatory compliance within the Felton system which also limits the District’s flexibility in other conjunctive use projects.  Basically, the proposal is for the District to request relief from a State Water Resources Control Board requirement that prohibits diversions from Fall, Bull, and Bennett Creeks when flows in the San Lorenzo River are below certain levels, but which doesn’t actually result in any benefit to fish in these creeks.  The District is likely to pursue this but will need to coordinate with the City of Santa Cruz on its proposed revision of its water permits on the San Lorenzo River.

The second scenario would redirect currently unused excess winter and spring creek flows from the North system to the South system, allowing the South system wells to be rested, thereby reducing groundwater pumping by around 30%.  This would require only a non-emergency use authorization of the existing intertie.

The third scenario would decrease South system groundwater pumping by closer to 70% by tapping into the District’s longstanding-but-currently-unused allotment of Loch Lomond reservoir water.  This would modestly increase baseflows from aquifers into Bean Creek, Zayante Creek, and the San Lorenzo River, with benefits for fisheries, but it would require a substantial investment in new infrastructure: connecting to the City’s pipeline, upgrading the District’s Kirby Street treatment plant, and negotiating a current fee for Loch Lomond water.

The fourth scenario, “Aquifer Storage and Recovery (ASR),” involves taking excess winter flows in creeks and injecting it into aquifers where it is stored for use in summer or in periods of extended drought.  It could provide greater benefits to the groundwater levels in aquifers and to creeks and groundwater-dependent ecosystems, but at a greatly increased cost due to the need for pipelines, expanded treatment plants, and the construction and operation of injection wells.  Moreover, it would require pilot studies to determine whether it would work in the Lompico Formation rocks that make up the main overdrawn aquifer.  For these reasons, it was not investigated in detail.

Following Mike’s presentation, Megan Jones of Rincon Consultants briefly explained the plan for California Environmental Quality Act (CEQA) compliance.  The goal of CEQA is to inform decision making and disclose potentially significant environmental impacts.  An Initial Study – Mitigated Negative Declaration (IS-MND) is being prepared for the three studied scenarios.  The public review period for the Draft IS-MND is estimated to be begin in July 2021.  The Final IS-MND and Board Approval should be in September 2021.

The presentation was followed by a Q&A session with both Directors and members of the public.  Director Ackemann asked about potential interactions with the City of Santa Cruz, and Carly said the District will try to work with the City.  District Manager Rick Rogers said he did not expect the city to derail the District’s proposal.  Directors Smolley and Fultz each asked about various details in the presentation.  There was also some general discussion of the considerable challenges involved in assessing the expected performance of ASR.

Alina Layng asked how the District planned to protect fish while taking extra surface water.  She also asked how the District effectively reviewed this with no biologist on Staff or on the Board.  Carly replied that Mike Podlech is the biologist on this project, and Megan Jones added that Rincon is using an in-house biologist as well.  Mike explained that the North System diversions would be small and appropriately managed.  He said there would still be some more detailed future analysis with regulatory agencies to establish allowable restrictions, but the preliminary analysis suggests that this project is doable while still protecting fish.

Cynthia Dzendzel questioned whether the acquisition agreement with Felton allowed for its water to be sent to other parts of the District.  Rick Rogers said he was unaware of any contractual restriction but would investigate further.

 

The meeting was adjourned at 7:20 PM.