First Steps in Inter-Basin Coordination for SGMA Basin Boundary Modification Requests in Santa Cruz County Cameron Tana, Sean Culkin, Nicholas Byler, and Derrik Williams HydroMetrics Water Resources Inc., Oakland CA, USA, [email protected] Text Text Text Pacific Ocean A B Purisima Highlands Subbasin E D C Pajaro Valley Subbasin West Santa Cruz Terrace Basin Santa Cruz Mid-County Basin Santa Margarita Basin 0 4 2 Miles 5 Service Layer Credits: Sources: Esri, HERE, DeLorme, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan, METI, Esri China (Hong Kong), swisstopo, MapmyIndia, © OpenStreetMap Three eligible agencies in Santa Cruz County submitted basin boundary modification requests under the Sustainable Groundwater Management Act (SGMA) to California Department of Water Resources (DWR) during the first submittal period ending March 2016. DWR has recommended approval of the modifications which would result in three basins defined based on the groundwater resource providing supply for each agency. These modifications involved shared boundaries between the proposed basins. The basin boundary modifications have the advantage of removing the need for intra-basin coordination agreements between the agencies, but inter-basin coordination will still be necessary for these connected basins. By collaboratively working on the modifications of the shared basin boundaries, the agencies have taken good first steps for future inter-basin coordination to achieve groundwater sustainability in Santa Cruz County. Prepared for Poster Presentation 2016 Conference & Annual Meeting September 28-29, 2016 Groundwater Resources Association of CA HydroMetrics WRI work under contract to: Scotts Valley Water District (SVWD) Santa Cruz Mid-County Groundwater Agency (MGA) Pajaro Valley Water Management Agency (PVWMA) Poster Design: Georgina King Santa Cruz Mid-County Basin Purisima Highlands Subbasin Santa Margarita Basin Final Boundary Proposed Boundary Jarvis Mutual Water Co. Hidden Falls Girl Scout Camp Tm Tp Tlo Tsc Tsc Tp Tlo Tp Qal Tsm Tp Tsc Tp Tp Tsc Tp Qal Qal Tsc Tla Tp Tp Tm Qal qd Qal Qal Qof Tsm Qof Tp Tm Qt Tsc qd Qt Qal Qof Purisima MWC Enchanted Valley Laurel Glen MWC Revision Based on Local Input Purisima Mutual Water Company submitted a letter of opposition to SVWD and MGA s proposed shared boundary arguing that it should be in the Mid-County Basin, not the Santa Margarita Basin as proposed. The aquifer units of the basins overlap in this area so both positions are scientifically justified. SVWD and MGA collaborated on a revision that addressed Purisima MWC s comments. Santa Cruz Mid-County Basin Purisima Highlands Subbasin Pajaro Valley Subbasin Z a y a n te F a ul t CWD PVWMA C D 0 2 1 Miles E Revision to Monterey County Subbasins PVWMA s modification request defines the Pajaro Valley Subbasin boundary based on PVWMA s jurisdiction without creating new basins. This requires increasing the area of Salinas Valley subbasins. PVWMA obtained a letter from Monterey County Water Resources Agency (MCWRA) during the public comment period supporting the expansion of the Salinas Valley subbasins as the expanded areas includes MCWRA s existing management zones. ! ( ! ( ! ( ! ( West Santa Cruz Terrace Basin Santa Cruz Mid-County Basin Santa Margarita Basin Feet of Saturated Alluvium Tlo Tp Tp Tp Qal Qal Tsm Qal Tsc qd Tlo Tl Qt Qal Tl Tsc Tp Qt qd qd Qal qd sch Tl Tlo Qt Qal Tsm Tsm qd Tsm Qal Tp Tsm sch Tsm Tp sch Qt Qcu Qcu Qcu Qcu Qal sch Qcu Tsm Qal sch Qal Qt Qcu Qt Qcu Qal Tsm m Qt qd m m Qcl Qcl Tsm Tsm Tsm Qcl Qal Tsc Qcu Tsm Qcu Qcu Tp Qcu qd Qcu Tp Qb Qcu Qcl Tsm Tsm Tsm Tp Tsm Qcu Qcu Tsm Tsc Tsm Qb Qcl Tsc Tsc Qcu Qal Qal Tp Qb Qbs Qbs Qcl Tsc Qcl Qcl Qcl Qbs 10 9 0 0 Response to DWR Modification In approving the Santa Margarita Basin, DWR originally proposed a modification that extended the basin down to the existing West Santa Cruz Terrace Basin. On behalf of SVWD, HydroMetrics WRI provided information accepted by DWR that limited the southern extent of Santa Margarita Basin. HydroMetrics WRI suggested possibly extending the expected low priority West Santa Cruz Terrace Basin northward instead. This suggestion was made after consultation with MGA member City of Santa Cruz, the agency within West Santa Cruz Terrace Basin. B 0 1 0.5 Miles Granitic Divide Santa Margarita Basin West Santa Cruz Terrace Basin Santa Cruz Mid-County Basin Purisima Highlands Subbasin 400 400 400 400 300 -1100 100 500 200 600 800 -1000 300 200 700 -2000 600 -900 0 500 400 200 200 -800 500 100 -700 300 500 200 600 300 -600 400 -500 -800 500 -700 -600 -400 -500 200 -400 -300 -200 500 -100 -300 300 200 -200 100 400 300 -1100 -100 0 -1000 -900 400 100 Tsm Tlo Tp Tp Tp Tsc Tp Qal Tsc Tla Tp Tp Tm Qal qd Qal Qal Qof Tsm Tsm Qof Tp Tm Qt Tsc qd Tl Qt Qal Qof Qof Tsc Tp Qt Qal qd sch Qt Qal Tsm qd Tsm Tsm Qal Tp Tsm Tp sch Qt Qcu Qcu Qal sch Scientific Justification for Shared Boundary SVWD and MGA recognized in early planning the need to coordinate basin boundary modification where aquifer units of basins overlap. MGA agreed with SVWD s conceptual proposal to include all aquifer units that provide water supply to SVWD as part of the Santa Margarita Basin. The boundary between the two basins was then modified on the scientific basis of a geologic structural divide in the granite basement rock underlying the aquifers of each basin. HydroMetrics WRI worked with a former Santa Cruz County geologist to refine the alignment of this divide, which had also been identified in previous studies of the area. A 0 1 0.5 Miles 0 1 0.5 Miles Keeping Water Agencies within Single Basins Recognizing PVWMA s exclusive right under SGMA to be the Groundwater Sustainability Agency (GSA) for its jurisdiction, MGA s request for the Mid-County Basin boundary was based on PVWMA s jurisdiction. Also, Mid-County Basin includes the whole jurisdiction of MGA member Central Water District (CWD) so that CWD is not also in the Purisima Highlands Subbasin. The expected low priority of this subbasin was communicated to PVWMA which had not yet decided to submit its modification request to prevent overlap with this subbasin. Central Water District Pajaro Valley Water Management Agency Proposed Basin Modifications Pajaro Valley Subbasin Salinas Valley Basin 2003 High Priority Basins Pajaro Valley 0 2 1 Miles 2003 Low Priority Basins Scotts Valley Felton 2003 Medium Priority Basins West Santa Cruz Terrace Santa Cruz Purisima Formation 2003 High Priority Basins Soquel Valley Pajaro Valley Shaded Basins are 2003 DWR Basins. Outlined Basins are Proposed Basins Process Timeline E C A E B A D Jan 2015 SGMA becomes law Feb 2015 Meeting of Agencies with DWR Aug 2015 MGA and SVWD begin coordination for shared boundary Sept 2015 PVWMA declares as GSA Oct 2015 DWR adopts emergency regulations Dec 2015 MGA and SVWD coordinate on notice for local input Jan 2016 MGA and SVWD coordinate on revision based on local input Mar 2016 MGA & SVWD submit basin boundary requests & PVWMA initiates & submits basin boudary request April-May 2016 Agency letters of support provided for PVWMA request July 2016 SVWD respose to DWR's modification to request for Santa Margarita Basin Sept 2016 DWR to publish final modifications June 2016 MGA declares as GSA Request submitted by MGA predecessor Soquel-Aptos Groundwater Management Committee. MGA members are Central Water District, City of Santa Cruz, County of Santa Cruz and Soquel Creek Water District. 1 Modified Basin Requesting Agency Santa Margarita Basin Scotts Valley Water District (SVWD) Santa Cruz Mid- County Basin Santa Cruz Mid-County Groundwater Agency (MGA) 1 Pajaro Valley Subbasin Pajaro Valley Water Management Agency (PVWMA)