Stacey Harrington, M.S, R.E.H.S. Napa County Environmental Management Coordinator

Transcription

1 Stacey Harrington, M.S, R.E.H.S. Napa County Environmental Management Coordinator

2 How many people view the Napa County regions:

3 How groundwater management folks see Napa County

4 Brief History During the drought in 1990, the Napa County Board of Supervisors and the Planning Commission became concerned about the approval of use permits and parcel divisions and their impacts on groundwater availability. As a result, water availability analyses were required for use permits and parcel divisions. In 1999, the Groundwater Conservation Ordinance was passed to minimize the dropping groundwater levels in the Milliken-Sarco-Tulocay Basin.

5 Water Availability Analysis In general, parcels located on the Valley Floor or in strong alluvial areas were assigned a threshold of 1 acre-foot per acre of land (an acre-foot of water is the amount of water it takes to cover one acre of land to a depth of one foot, or 325,851 gallons). Therefore, a 40- acre parcel will have an acceptable level of groundwater use of 40 acre-feet per year. The threshold for hillside parcels (primarily located in volcanic rock and soils) was 0.5 acre-feet per acre or 20 acre-feet per year for a 40-acre parcel.

6 Water Availability Analysis A simplified method for evaluating water availability in a cost effective manner, originally created with minimal groundwater data. Phase 1: If within 50% of the estimated threshold, a water meter may be required to verify actual use. If the project exceeds the threshold, water use can be reduced. Phase 2 and Phase 3: Not really used. Phase 2: An aquifer test to verify if the proposed wells impact neighboring wells. Phase 3 includes mitigation measures but is even more vague.

7 Water Availability Analysis (cont d) Phase 3: Determines possible actions that could be taken to moderate the immediate effects of groundwater pumping, including measures to reduce water consumption and/or the maximum pumping rate.

8 The Milliken-Sarco-Tulocay (MST) Groundwater Deficient Basin

9 The Milliken-Sarco-Tulocay (MST) Groundwater Deficient Basin

10 The MST USGS studies for decades showed declining groundwater levels 1999 BOS declares a groundwater deficient basin and passes Groundwater Ordinance requiring permitting of new uses and establishing Fair Share 2003 Latest USGS study shows continuing decline 2004 Planning Department adopts no net increase standard for discretionary permits under CEQA

11 The Groundwater Ordinance Designed to slow the problem, not fix it Established fair share concept based on calculated recharge/#acres (0.3 acre ft/acre/yr) Only applied to new development (does not regulate existing uses) Required discretionary permits for most new uses (allows a few ministerial uses) Most new projects required metering of wells, reporting to County and limited amount of water withdrawn based on the fair share

12 CEQA Joins the MST Party Additional requirement of no net increase added in 2004 (following 2003 USGS Study) to stay under cumulative impacts requirement of CEQA Essentially any discretionary project that increases groundwater use by any amount is cumulatively significant and requires an EIR As a practical reality approvals grind to a halt (unless you have an existing water using activity you can give up for a new but different water using activity)

13 What can be done in the MST? Exempt: Minor or convenience improvements to an existing well system (repairs/changes not intended to supply more water) Replacement of a failed well Expansion of an existing dwelling (add bedrooms but not a second unit) Ministerial: A residence, if no other development exists on the parcel (limited to 0.6 acre ft/year no matter the size of the parcel) Replants

14 More on the MST Discretionary: Everything else that uses groundwater There are a few ways to facilitate development: Trucked in water (only for agricultural uses) Giving up one use to allow for another Reducing water use in one area of the parcel to support development in another

15 Groundwater: What we know Napa County and other public agencies have been monitoring groundwater resources since mid-1900 s Groundwater Levels The Napa Valley Floor shows stable long-term trends and shallow depth to water Milliken, Sarco & Tulocay creek watersheds show historical declines but some areas have begun to stabilize

16 Groundwater: What we know Groundwater Quality Quality generally good on Napa Valley Floor Higher levels of salt and other constituents in northern Napa Valley Floor/Calistoga Salts, iron and other constituents are higher in southern Napa Valley Floor Groundwater Recharge Most recharge occurs in the Napa River watershed Almost 43% of the watershed has geology/soils with the greatest potential for recharge

17 The Current Plan Groundwater Outreach & Education Expanded Monitoring Program and Annual Reporting to ensure long-term sustainability (General Plan goal) Update of County s Water Availability Analysis and Groundwater Ordinance underway. March 2015 draft WAA maintains 1 ac/ft/yr for the valley floor and.3 ac/ft/yr for the MST area Because of the varying geology in other areas, a single number for water use isn t provided; it varies by parcel and well/spring interference must be considered Water use evaluated for discretionary permits Extending Recycled Water to the MST and Carneros Expanded Water Conservation Program Efforts

18 Voluntary Milliken-Sarco-Tulocay Recycled Water Project

19 Groundwater Sustainability Objectives Groundwater Sustainability (definition) Groundwater sustainability depends on the development and use of groundwater in a manner that can be maintained indefinitely without causing unacceptable economic, environmental, or social consequences, while protecting economic, environmental, and social benefits. As such, groundwater sustainability is both a goal and a process. Groundwater sustainability is a shared responsibility of everyone that lives and works in the County.