B. Description of Proposed Boundary Modification

1. Short Description

   Scientific-based modification to the boundary of the San Diego River Valley Groundwater Basin (Basin 9-015) to more accurately depict the alluvial limits of the Basin.
2. Type of basin boundary revision

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

   This boundary modification request is being made in response to discrepancies between the existing lateral Basin boundaries and the mapped extent of alluvium within the Basin. In accordance with Bulletin 118 and published research, the alluvium is the principal water-bearing formation within the Basin, therefore it is necessary for the Basin boundaries to incorporate and be consistent with the scientifically recognized hydrogeologic boundaries. Once the Basin boundaries accurately represent the alluvial extent, an adequate water budget can then be developed for the purposes of sustainable management under SGMA.

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

   • 9-015 SAN DIEGO RIVER VALLEY
5. Provide the proposed name for the new basin(s) or subbasin(s)

   San Diego River Valley

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)
   	9-015 SAN DIEGO RIVER VALLEY

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):

• size: 1
• D.1. Statutory and Legal Authority.pdf (5.2MB) Uploaded on 07/06/2018 at 01:44PM

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

Attachment(s):

• size: 1
• D.2. Resolution, Meeting Agenda and Summary.pdf (720.9kB) Uploaded on 07/06/2018 at 01:44PM

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):

• size: 1
• D.3. Figures.pdf (7MB) Uploaded on 10/19/2018 at 12:54PM

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

Attachment(s):

• size: 1
• SDRGWB_Proposed_modified_20181010.zip (49kB) Uploaded on 10/18/2018 at 12:10PM

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

Attachment(s):

• size: 1
• SDRGWB_MuniBndy_And_WtrDist.zip (895.7kB) Uploaded on 07/25/2018 at 11:43AM

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

Modification of the Basin boundary is not currently pursuant to 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.

A description of the Basin boundaries is included in the attachment.

Attachment(s):

• size: 2
• Sycamore Landfill Boring Logs.PDF (2.5MB) Uploaded on 10/01/2018 at 09:18AM
• E. Basin Boundaries.docx (38.2kB) Uploaded on 10/23/2018 at 02:13PM

F. Notice and Consultation

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

City of San Diego City of Santee County of San Diego Padre Dam Municipal Water District Lakeside Water District Helix Water District

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

The interested local agencies and public water systems in the Basin were identified by the requesting agency through review of publicly available water district boundary maps, political boundaries, and from institutional knowledge of agency staff. In addition, local agencies and public water systems were identified during a SGMA GSA stakeholder meeting for the Basin (see attached) and public meetings to discuss the Basin boundary modifications as described in F.3, below.

Attachment(s):

• size: 1
• F.2. SGMA 2016 Meeting.pdf (336.4kB) Uploaded on 07/06/2018 at 01:49PM

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.

Public meetings were held on May 17 and June 19, 2018 to discuss the proposed Basin boundary modifications with affected and/or interested local agencies and public water systems (see F.4. for meeting agendas and summaries). Letters of support are attached and have been received by the County of San Diego, Padre Dam Municipal Water District, Lakeside Water District, Helix Water District, and City of Santee.

Attachment(s):

• size: 1
• F.3. Letters of Support.pdf (865.8kB) Uploaded on 07/06/2018 at 01:49PM

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.

Public meetings were held on May 17 and June 19, 2018 to discuss the proposed Basin boundary modifications. During the June 19, 2018 meeting, the city council voted unanimously to adopt Resolution R-2018-584 (attached to D.2) to apply to the DWR for a basin boundary modification for the San Diego River Valley Groundwater Basin pursuant to the Sustainable Groundwater Management Act (SGMA). The agendas and summaries are attached.

Attachment(s):

• size: 1
• F.4. Meeting Agendas and Summaries.pdf (1.1MB) Uploaded on 07/06/2018 at 01:50PM

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.

No additional comments were received by or responses made by the requesting agency.

H. Local Support

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

See F.3 and F.4. The public meeting held on May 17, 2018 and the letters of support serve as evidence that sufficient information was provided to the affected agencies and systems.

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.

See F.3. Letters of support were provided by the County of San Diego, Padre Dam Municipal Water District, Lakeside Water District, Helix Water District, and City of Santee. These letters were signed by the appropriate delegated authority who represents each agency.

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

No oppositions to the proposed boundary modification have been received.

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.

Please see the attached description of the Hydrogeologic Conceptual Model for the San Diego River Valley Groundwater Basin.

Attachment(s):

• size: 1
• I. Hydrogeologic Conceptual Model.docx (39.6kB) Uploaded on 07/24/2018 at 01:04PM

J. Technical Studies for External Scientific Modifications

1. A qualified map that depicts the lateral boundaries of the aquifers that define the basin or subbasin.

Geologic Map of the San Diego 30 x 60 Quadrangle (1:100,000) (Kennedy and Tan, 2008): https://ngmdb.usgs.gov/Prodesc/proddesc_84173.htm Preliminary Geologic Map of the El Cajon 30 x 60 Quadrangle (1:100,000) (Todd et. al., 2004): https://ngmdb.usgs.gov/Prodesc/proddesc_69595.htm (attached) Geologic Map of the El Cajon Mountain Quadrangle (1:24,000) (Todd, 1983): https://ngmdb.usgs.gov/Prodesc/proddesc_14218.htm (attached)

Attachment(s):

• size: 2
• El Cajon 30' x 60'.pdf (10.4MB) Uploaded on 07/06/2018 at 02:28PM
• El Cajon Mountain.pdf (12.3MB) Uploaded on 07/06/2018 at 02:29PM

2. A technical study that provides subsurface data that demonstrates the vertical thickness and relevant physical properties of the alluvial aquifer or stacked series of alluvial aquifers.

Blatchford, Douglas, 2011. Santee Basin Aquifer Recharge Study, US Department of the Interior Bureau of Reclamation. (attached) Bondy and Huntley, 2001. Groundwater Management Planning Study, Santee - El Monte Basin. (attached) Izbicki, John A., 1985. Evaluation of the Mission, Santee, and Tijuana Hydrologic Subareas for Reclaimed-Water Use. (see URL)

URL: https://pubs.er.usgs.gov/publication/wri854032

Attachment(s):

• size: 2
• Blatchford, 2011.pdf (3.4MB) Uploaded on 07/06/2018 at 02:33PM
• Bondy and Huntley, 2001.pdf (12.7MB) Uploaded on 07/06/2018 at 02:33PM