B. Description of Proposed Boundary Modification

1. Short Description

   Minor modification of adjoining subbasins to align with county boundaries
2. Type of basin boundary revision

   • Jurisdiction Internal
3. Provide a narrative overview of the boundary modification request and how the resulting modification would affect likelihood of sustainable management.

   The Sonoma Valley Groundwater Sustainability Agency is requesting a jurisdictional basin boundary modification, changing the boundaries of the Sonoma Valley Subbasin and the Napa-Sonoma Lowlands Subbasin to align with the county boundary between Sonoma and Napa Counties. While the existing Bulletin 118 boundary between the two basins generally matches the Sonoma-Napa county boundary, there are some areas of overlap. These areas of overlap include approximately 347 Sonoma County acres, including portions of seven parcels, that are currently located within the Sonoma Napa-Sonoma Lowlands Subbasin and approximately 160 Napa County acres, including portions of six parcels, that are currently located within the Sonoma Valley Subbasin. The proposed modification will enhance the likelihood for sustainable management by simplifying the governance of the subbasins, allowing entities to focus their efforts of groundwater management in their respective county and reduce jurisdictional overlap. The total area requested to be changed represents less than 1% of the area of the two subbasins. The modification will not result in any areas to become unmanaged.

   Attachment(s):
4. List the existing basin(s)/subbasin(s) to be modified by this request

   • 2-002.02 NAPA-SONOMA VALLEY - SONOMA VALLEY
   • 2-002.03 NAPA-SONOMA VALLEY - NAPA-SONOMA LOWLANDS
5. Provide the proposed name for the new basin(s) or subbasin(s)

C. Initial Notification and Combination of Requests

1. Was an initial notification submitted to the Department?

   Yes
   List of submitted initial notification for the selected basin(s)/subbasin(s).

   Local Agency	Potential Basin(s)/Subbasin(s)
   	2-002.02 NAPA-SONOMA VALLEY - SONOMA VALLEY , 2-002.03 NAPA-SONOMA VALLEY - NAPA-SONOMA LOWLANDS

2. Does this application include a combination of requests?

   No

D. Required Documents for All Modifications

1. A copy of the statutory or other legal authority under which the requesting agency was created with specific citations to the provisions setting forth the duties and responsibilities of the agency.

Attachment(s):

• SV GSA Joint Exercise of Powers Agreement-Executed.pdf (1.4MB) Uploaded on 09/26/2018 at 04:03PM

2. A copy of the signed resolution adopted by the requesting agency formally initiating the boundary modification request process.

Attachment(s):

• SV GSA resolution in support of BBM.pdf (74kB) Uploaded on 09/26/2018 at 04:03PM

3. A map of adequate scale (no greater than 1:24,000; e.g., 1:10,000 is not acceptable) showing the proposed modified basin boundary in relation to the existing Bulletin-118 basin boundary and the local agencies that are within or bordering the existing and proposed basin.

Attachment(s):

• SV basin boundary request Water Districts.pdf (1.7MB) Uploaded on 09/26/2018 at 04:08PM

4. A GIS shapefile of the proposed modified groundwater basin boundaries. Download Existing B118 basin shape file | DWR Spatial Data Standards

Attachment(s):

• Sonoma Valley Basin Boundary Mod Teale Attributes.zip (27kB) Uploaded on 09/27/2018 at 10:10AM

5. A GIS shapefile of the political boundaries of any affected or adjacent local agency. Download water agency shape file

Attachment(s):

• Water Districts SV BBM application.zip (87.5kB) Uploaded on 09/26/2018 at 04:08PM

6. Any information, if necessary, to enable DWR to satisfy the requirements of a responsible agency pursuant to the California Environmental Quality Act.

The proposed modification is an administrative action and is therefore not a Project defined by CEQA.

E. General Information

1. Describe the lateral boundaries of the alluvial aquifer or aquifers that form the groundwater basin and the definable bottom of the basin. The description must be in terms that are clear, definite, and sufficiently detailed to allow an authoritative map of the proposed basin boundaries to be plotted using the given description.

Attachment(s):

• Sonoma Valley BBM proposal description.docx (15.7kB) Uploaded on 09/26/2018 at 04:11PM

F. Notice and Consultation

1. List all local agencies and public water systems affected by the basin(s) modification request.

County of Napa Napa County Flood Control and Water Conservation District Los Carneros Water District County of Sonoma

2. Explain the methods used to identify interested local agencies and public water systems in the affected basin(s):

Selected local agencies and public water systems that overlap areas affected by the Basin Boundary Modification request in a GIS.

3. Provide information regarding the nature of consultations with affected or interested agencies. Attach and cite any copies of correspondences with local agencies and public water systems and/or any other persons or entities consulted.

Attachment(s):

• Correspondence with Napa.docx (15.2kB) Uploaded on 09/26/2018 at 04:14PM

4. Provide a summary of all public meetings at which the proposed boundary modification was discussed or considered by the requesting agency. Attach and cite any copies of agendas and notices published.

On August 27, 2018, the Sonoma Valley Groundwater Sustainability Agency Board of Directors held a public meeting. The Basin Boundary Modification was presented by staff and there were no public comments on the matter. The presentation detailed the number of acres affected by the proposed modification and highlighted that implementing the modification would simplify roles of groundwater management in the affected areas.

Attachment(s):

• Board of Directors Meeting _ Sonoma Valley Groundwater Sustainability Agency.pdf (191.3kB) Uploaded on 09/26/2018 at 05:49PM
• 8-27-18_SV-Board-Meeting-Agenda_ada.pdf (206.1kB) Uploaded on 09/26/2018 at 04:15PM

5. Attach a copy of all comments regarding the proposed boundary modification received by the requesting agency and a summary of any responses made by the requesting agency.

Attachment(s):

• LCWD Ltr of Sup for Subbasin Boundary 9.28.2018.pdf (487.6kB) Uploaded on 09/28/2018 at 09:32AM
• SV GSA resolution in support of BBM.pdf (74kB) Uploaded on 09/26/2018 at 04:15PM
• Letter of Support_Sonoma Valley_and_Lowlands Subbasins Boundary Mod_7Sept2018.final.pdf (441.9kB) Uploaded on 09/26/2018 at 04:15PM
• Flood-Napa Sonoma Boundary Mod Support Letter.pdf (385.7kB) Uploaded on 09/26/2018 at 04:16PM
• 9-5-18_Letter of Support _SonomaCounty_Sonoma Water.pdf (113.5kB) Uploaded on 09/26/2018 at 04:16PM

G. General Existing Groundwater Management

1. Explain how sustainable groundwater management exists or could likely be achieved in the basin:

In 2007 a voluntary groundwater management plan was completed for the Sonoma Creek watershed which overlies the Sonoma County portion of the Sonoma Valley Subbasin. The Plan was prepared under the authority of the Groundwater Management Act Water Code §10750 et seq., originally enacted as Assembly Bill (AB) 3030. The goal of the Plan was to locally manage, protect, and enhance groundwater resources for all beneficial uses, in a sustainable, environmentally sound, economical, and equitable manner for generations to come. The Sonoma Valley Groundwater Sustainability Agency was formed in 2017 after the passage of SGMA and identification of the Sonoma Valley Subbasin as medium priority. The County of Sonoma, North Bay Water District, Sonoma Resource Conservation District, City of Sonoma, Sonoma County Water Agency, and Valley of the Moon Water District are the GSA member agencies.

2. Explain how the proposed boundary modification would affect the ability of adjacent groundwater basins to sustainably manage groundwater in those groundwater basins.

If approved the modification would remove Sonoma County from the Napa-Sonoma Lowlands and would remove Napa County from the Sonoma Valley Subbasin. The proposed modification would simplify and improve the sustainable management for the Sonoma Valley Subbasin and Napa-Sonoma Valley Subbasin by minimizing jurisdictional overlap.

3. Provide a historical summary of the sustainable management of groundwater levels in the proposed basin(s) or subbasin(s).

A USGS study of the Sonoma Valley Subbasin and watershed was completed in 2006. Between 2007-2017, basin stakeholders engaged in a voluntary Groundwater Management Program, which included the adoption of the Sonoma Valley Groundwater Management Plan (2007) and an update and report (2014). There are two areas of groundwater depression within the Sonoma Valley Subbasin. These depressions occur in the deeper, confined zones, near El Verano and north, and east, of the City of Sonoma. Groundwater levels near the Huichica area in the southeast part of the basin began to decline, but following the delivery of recycled water, water levels have begun to recover. Shallower groundwater levels are generally stable throughout the subbasin.

4. Discuss potential impacts to state programs resulting from the proposed boundary modification, including, but not limited to, the California Statewide Groundwater Elevation Monitoring (CASGEM), Groundwater Management Plans developed pursuant to AB 3030, Groundwater Sustainability Plans developed pursuant to the Sustainable Groundwater Management Act, any applicable state or regional board plans, and other water management and land use programs.

It is expected that no state programs will be affected by this modification as the modification would not result in any unmanaged areas. There are no CASGEM wells in the area affected by the change. The Sonoma Valley Groundwater Management Plan is superseded by SGMA legislation and will not be negatively affected by this change. It is expected that groundwater management will be improved by these changes due to decreased jurisdictional overlap.

H. Local Support

1. Provide any evidence that sufficient information was provided to affected agencies and systems regarding the proposed boundary modification.

Attachment(s):

• Correspondence with Napa.docx (15.2kB) Uploaded on 09/26/2018 at 04:18PM

2. Provide a list of all affected agencies and affected systems that submitted comments and/or documents in support or opposition to the proposed boundary. The agency submitting their support or opposition for a boundary modification must provide a copy of a resolution formally adopted by the decision-making body of the affected agency or system or a letter signed by an executive officer or other official with appropriate delegated authority who represents the agency or system. Attach copies of the resolution and/or signed letter detailing the support or opposition submitted.

Sonoma Valley Groundwater Sustainability Agency County of Sonoma and Sonoma County Water Agency County of Napa Napa County Flood and Water Conservation District

Attachment(s):

• SV GSA resolution in support of BBM.pdf (74kB) Uploaded on 09/26/2018 at 04:15PM
• Letter of Support_Sonoma Valley_and_Lowlands Subbasins Boundary Mod_7Sept2018.final.pdf (441.9kB) Uploaded on 09/26/2018 at 04:15PM
• Flood-Napa Sonoma Boundary Mod Support Letter.pdf (385.7kB) Uploaded on 09/26/2018 at 04:16PM
• 9-5-18_Letter of Support _SonomaCounty_Sonoma Water.pdf (113.5kB) Uploaded on 09/26/2018 at 04:16PM

3. Provide any evidence that rebuts any opposition to the proposed boundary modification.

The Sonoma Valley GSA has received no opposition to the proposed boundary modification request.

I. Hydrogeologic Conceptual Model

1. Principal aquifer units within requested basin.
2. Lateral boundaries of the proposed basin, including:
   1. Geologic features that significantly impede or impact groundwater flow.
   2. Aquifer characteristics that significantly impede or impact groundwater flow.
   3. Significant geologic and hydrologic features and conditions of the principle aquifer units, as appropriate, including information regarding the confined or unconfined nature of the aquifer, facies changes, truncation of units, the presence of faults or folds that impede groundwater flow, or other groundwater flow restricting features.
   4. Key surface water bodies, groundwater divides and significant recharge sources.
3. Recharge and discharge areas within the basin.
4. Definable bottom of the basin or subbasin.

The department may waive this requirement for an internal boundary modification if the requesting agency is able to demonstrate that the proposed boundary modification is unlikely to affect sustainable groundwater management.

The SV GSA requests that this requirement be waived. This modification would result in less than 1% of the jurisdictional coverage of the Sonoma Valley and Napa-Sonoma Lowlands Subbasins area to be changed. This modification would result in a reduction of jurisdictional overlap which would likely improve sustainable management in the two subbasins.

L. Technical Studies for All Jurisdictional Modifications

1. A water management plan that covers or is in the immediate vicinity of the proposed basin or portion of the proposed basin and satisfies the requirement of Water Code sections 10753.7(a) or 10727 by attaching one of the following:
   1. An adopted groundwater management plan, a basin wide management plan, or other integrated regional water management program or plan.
   2. Management pursuant to an adjudication action.
   3. One or more technical studies that cover the relevant portion of a basin or subbasin and adjacent areas.

URL: http://www.scwa.ca.gov/files/docs/projects/svgw/130_Sonoma-Valley-Groundwater-Management-Plan-Dec-2007.pdf

2. A statement of the existing and planned coordination of sustainable groundwater management activities and responsibilities where required.

The Sonoma Valley GSA will coordinate and communicate with Napa County regarding development of its GSP and possible management actions.