Sacramento County Water Resources - 5-021.66 SACRAMENTO VALLEY - SOLANO, 5-022.15 SAN JOAQUIN VALLEY - TRACY

Sacramento County Water Resources - 5-021.66 SACRAMENTO VALLEY - SOLANO, 5-022.15 SAN JOAQUIN VALLEY - TRACY

A. Applicant Information

Requesting Agency Information
Agency Name: Sacramento County Water Resources
Address: 827 7th Street
City: Sacramento Zip: 95814
Work Phone: (916) 874-1085 Cell Phone: (916) 479-4701
Email: dornl@saccounty.net Fax:
Revision Request Manager Information
Person Name: Linda Dorn
Address: 827 7th street
City: Sacramento Zip: 95814
Work Phone: 916-874-1085 Cell Phone:
Email: dornl@saccounty.net Fax:
 

B. Description of Proposed Boundary Modification

  1. Modification to shift <600 acres of water and land from the Tracy Subbasin to the Solano Subbasin
    • Jurisdiction Internal
  2. The boundary modification will affect stream boundary segment 16-17 of the Solano Subbasin and stream segment 6-7 of the Tracy Subbasin, which are based on the flowline from the National Hydrography Dataset for the San Joaquin River. The southern boundary of Sacramento County is similar to the flowline, except in the vicinity of West Island, where the County boundary is south of the island and the basin boundary is north of the island. The boundary modification will affect a 3-mile long portion of the 21-mile long common boundary between Sacramento County and Contra Costa County, and shift the current basin boundary up to 0.5 miles south to the Sacramento County boundary. The approximate 600-acre (440 acres of water and 140 acres of uninhabitable land) modification area will shift from the Tracy Subbasin to the Solano Subbasin, as part of the Sacramento County Groundwater Sustainability Agency (GSA). The boundary modification will facilitate Sacramento County management of groundwater resources by shifting a very small unmanaged GSA area within the Tracy Subbasin to a much larger unmanaged GSA area in the Solano Subbasin, both areas were included in the Sacramento County GSA. The modification will not affect sustainable management because the nominal 600-acre area is located in the San Joaquin River. The area is comprised mostly of water (>70%) with the remainder known as West Island (<30%), which is uninhabited and undeveloped, except for two support structures for overhead power lines.
    • 5-021.66 SACRAMENTO VALLEY - SOLANO
    • 5-022.15 SAN JOAQUIN VALLEY - TRACY

C. Initial Notification and Combination of Requests

  1. Yes
    Local Agency Potential Basin(s)/Subbasin(s)
    Yolo County Flood Control And Water Conservation District 5-021.52 SACRAMENTO VALLEY - COLUSA , 5-021.67 SACRAMENTO VALLEY - YOLO , 5-021.66 SACRAMENTO VALLEY - SOLANO
    Northern Delta GSA 5-021.65 SACRAMENTO VALLEY - SOUTH AMERICAN , 5-022.01 SAN JOAQUIN VALLEY - EASTERN SAN JOAQUIN , 5-021.66 SACRAMENTO VALLEY - SOLANO
    5-021.67 SACRAMENTO VALLEY - YOLO , 5-021.66 SACRAMENTO VALLEY - SOLANO
    5-022.15 SAN JOAQUIN VALLEY - TRACY , 5-021.66 SACRAMENTO VALLEY - SOLANO
    5-021.66 SACRAMENTO VALLEY - SOLANO , 5-021.65 SACRAMENTO VALLEY - SOUTH AMERICAN , 5-022.01 SAN JOAQUIN VALLEY - EASTERN SAN JOAQUIN
    San Luis & Delta-Mendota Water Authority 5-022.07 SAN JOAQUIN VALLEY - DELTA-MENDOTA , 5-022.15 SAN JOAQUIN VALLEY - TRACY
    Brentwood City Of 5-022.15 SAN JOAQUIN VALLEY - TRACY
    Brentwood City Of 5-022.15 SAN JOAQUIN VALLEY - TRACY
    Lathrop City Of 5-022.15 SAN JOAQUIN VALLEY - TRACY , 5-022.01 SAN JOAQUIN VALLEY - EASTERN SAN JOAQUIN
  2. No

D. Required Documents for All Modifications

This BBM should not be subject to CEQA because of the de minimis impact on groundwater management in either the Tracy or Solano Subbasins. The modification area is less than 600 acres, comprised of less than 30% land (West Island) and over 70% water (San Joaquin River). The BBM will increase the area of the Solano Subbasin by 0.14% and decrease the area of the Tracy Subbasin by 0.17%.

E. General Information

The lateral boundaries of the Solano Subbasin are defined by 19 segments, including five County segments, five Water Agency segments, five Steam segments, two Watershed segments, one Transportation segment, and one Unknown segment that is quite short and traverses the Sacramento River from a Water Agency to the County line. The primary segment types are Stream and Watershed and the secondary types are County and Water Agency (DWR BBDescribe, 2018). The bottom of the basin can be defined by the base of fresh groundwater (Berkstresser, 1973), which varies from less than 400 feet below sea level along the southwestern corner of the subbasin, in the vicinity of the modification area, to over 3,200 feet below sea level in a small crescent area approximately 12 miles south/southeast of Davis. West Island is uninhabited and groundwater conditions are not defined, as the 140-acre island is in the San Joaquin River.

F. Notice and Consultation

Sacramento County GSA - Slightly greater area for GSA in Solano Subbasin Solano Subbasin Groundwater Sustainability Agency-Slightly greater area for Solano Subbasin Contra Costa County GSA - Slightly less area in Tracy Subbasin
Utilized List of Interested Parties from Sacramento County GSA Notification. Telephone calls/emails with Contra Costa County GSA, Solano Subbasin GSA, North Delta JPA. Coordination Committee Meetings for the Solano Subbasin and East Contra Costa County GSA meeting.
See attached support letters from Solano Subbasin GSA, Contra Costa County GSA, Discovery Bay Community Services District GSA, East Contra Costa Irrigation District, and City of Antioch. See attached emails to Solano Subbasin GSA and Contra Costa County GSA.
- Sacramento County Board of Supervisors Meeting on January 9, 2018 (Attached - Item 29) - Solano Subbasin GSA Coordination Committee Meetings, January 16 and February 14, 2018 - Solano Subbasin GSA Board Meeting, February 8, 2018 (Agenda Attached - Item 10) - East Contra Costa County GSA March 14, 2018 Meeting (Email attached) - Cosumnes [Subbasin GSA] Working Group Meeting on February 21, 2018 - Sacramento County GSA announcement (Meeting Summary attached)
None through May 25, 2018

G. General Existing Groundwater Management

All requests for jurisdictional modification pursuant to Section 342.4 MUST include responses to the following questions.
The 600-acre modification area will not affect groundwater management in the Solano Subbasin because the area is only 0.14% of the entire subbasin, is located in the middle of the San Joaquin River, does not utilize any groundwater, and will not likely utilize groundwater in the future. Sustainable groundwater management will likely be achieved in the Solano Subbasin through the coordinated efforts of the seven GSAs in their preparation of a single Groundwater Sustainability Plan. Sacramento County, as the GSA for the modification area and other nearby Delta areas, will coordinate with the other GSAs of the Solano Subbasin to produce a complete GSP, as documented in the January 2018 Memorandum of Understanding (attached).
The Tracy Subbasin will not be affected by the boundary modification because groundwater is not and will not likely be developed on the small island (140 acres) within the ~600-acre modification area in the San Joaquin River.
Groundwater levels are not available for West Island, as the island is uninhabited and in the San Joaquin River. The groundwater would be shallow, fluctuate with river levels, and have comparable water quality to the river. The closest two wells are located south of the modification area in the Tracy Subbasin, including the 106-foot-deep Wilbur Deep Well (0.6 mile) and the 88-foot deep Blossom Well (1.1 miles). Both wells are part of the CASGEM program. At the Wilbur Deep Well, depths to groundwater (DtW) varied from 11 to 17 feet below ground (bg) between November 2014 and May 2015. At the Blossom Well, DtW varied from 32 to 35 feet bg between October 2014 and October 2017. In the Solano Subbasin, the closest two wells include a CASGEM well (COSAC3) at Brannon Island State Recreation Area, 6.9 miles to the northeast, along the Sacramento River, and a Voluntary Well to the north 9.9 miles in the Montezuma Hills. At the 416-foot deep COSAC3 well, DtW varied from 32 to 38 feet bg between April 2015 and October 2107. At the 130-foot deep Voluntary Well (04N/02E-22P1), DtW varied from 50 to 62 feet bg between October 2014 and October 2017. Water levels are available for this well, beginning in 1992, and the fall data show three overall trends. During first 10 years of data (1992 ? 2003), the mean DtW was 45 feet bg and showed a variable, but small overall water level decline of 1.3 feet per year. Between November 2003 and October 2004, the water level decreased nearly seven feet and remained variably at that level (mean: 52 feet bg) during the next eight years (2004 - 2012) with a negligible downward trend. Between December 2012 and December 2013, the water level decreased nearly 13 feet, but recovered somewhat during the next two years and the mean DtW has been approximately 60 feet bg during the last three fall measurements (2015 - 2017). Water level data are available for numerous wells further north in the Solano Subbasin but will not be affected by the basin boundary modification.
The basin boundary modification will not impact any state management program, including CASGEM.

H. Local Support

All requests for boundary modification must include the following:
Please see attachments to Notice and Consultation F(3)(4).
- Sacramento County Board of Supervisors Meeting on January 9, 2018 (Attached - Item 29) - Solano Subbasin GSA Coordination Committee Meetings, January 16 and February 14, 2018 - Solano Subbasin GSA Board Meeting, February 8, 2018 (Agenda Attached - Item 10) - East Contra Costa County GSA March 14, 2018 Meeting (Email attached) - Cosumnes [Subbasin GSA] Working Group Meeting on February 21, 2018 - Sacramento County GSA announcement (Meeting Summary attached)
None through May 18, 2018

I. Hydrogeologic Conceptual Model

Requests for boundary modification, must include a document or text to a clearly defined hydrogeologic conceptual model demonstrating each of the following:
Sacramento County requests a waiver from this item because the 600-acre modification area is located within the San Joaquin River, is mostly covered by water (>70%), and likely will not use groundwater for any purpose in the future. Groundwater conditions beneath West Island will be highly dependent on the flow and quality of the river. The HCM topics will be addressed in the GSP for the Solano Subbasin and Sacramento County GSA will participate in the preparation of that GSP. Sustainable groundwater management will not be affected by this small modification.

L. Technical Studies for All Jurisdictional Modifications

Requests for a jurisdictional boundary must attach or provide a URL or upload a file for the following:
Sacramento County is the GSA for much of the southwestern Delta area in the Solano Subbasin and the 600-acre modification area will be incorporated into a larger Sacramento County GSA in the Solano Subbasin. Sacramento County will continue to work with the other GSAs in Solano Subbasin to prepare and submit a GSP by January 2022 and to attain sustainable groundwater management in the Solano Subbasin by 2042.
Created on 05/17/2018 at 3:42PM, last modified on 06/20/2018 at 7:44AM and page generated on 09/15/2019 at 3:01AM