B. Description of Proposed Boundary Modification

1. Short Description

   Boundary modification for the Los Osos Valley Groundwater Basin (3-8) in San Luis Obispo County.
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.

   The proposed Los Osos Groundwater Basin modification request includes moving the western boundary from the bay shore to the coastline at the Pacific Ocean, moving the eastern boundary from the drainage divide to the east side of Warden Lake, and removing a portion of the southern beach area to match the best available scientific data, with five small exceptions (as depicted in the qualified map submitted in Section J.1 of this application). These minor exception areas are excluded in order to ensure the scientific boundary will result in a sustainably managed basin, consistent with the October 2015 final court order (litigation referenced in Water Code Section 10720.8(d)). Approval of the proposed scientific basin boundary with minor exceptions would result in sustainable management because it ensures alignment with the areas subject to implementation of the Basin Management Plan. The Basin Management Plan accepted in the final court order aims at taking bold, decisive and immediate actions to solve basin challenges and protect basin sustainability. Also, better alignment reduces governance conflicts that might inhibit sustainable management.

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

   • 3-008 LOS OSOS VALLEY
5. Provide the proposed name for the new basin(s) or subbasin(s)

   There are no new or consolidated basins proposed.

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)
   San Luis Obispo County

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):

• D.1 Legal Authority and Copy of Stipulated Judgment.pdf (17.2MB) Uploaded on 03/28/2016 at 10:57AM

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

Attachment(s):

• D.2 Resolution_County of San Luis Obispo.pdf (1.8MB) Uploaded on 03/28/2016 at 10:56AM

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):

• D.3 Proposed Modified Basin Boundary Map.pdf (146.4kB) Uploaded on 03/25/2016 at 10:25AM

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

Attachment(s):

• D4_GIS_Proposed LO Groundwater Boundary.zip (3.1kB) Uploaded on 03/25/2016 at 10:27AM

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

Attachment(s):

• D.5 GIS Political _Boundaries.zip (83kB) Uploaded on 03/25/2016 at 03:27PM

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

See Attachment D.6 for the California Environmental Quality Act.

Attachment(s):

• D.6 CEQA_Filed GRE.pdf (432.6kB) Uploaded on 03/25/2016 at 11:48AM

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.

The proposed Los Osos Valley Groundwater Basin is bounded on the north by Park Ridge, on the south by the Irish Hills, on the west by the Pacific Ocean, and on the east by Warden Lake (Attachment E.1 - Figure 1). In general hydrogeologic terms, the proposed lateral basin boundary is the onshore extent of the contiguous area overlying the principal aquifers. The proposed bottom of the basin is the base of permeable sediments, which is defined by the contiguous base of the stacked principal aquifers within the lateral basin boundary with at least one pre-Holocene aquifer present with the exception of five minor areas. These five areas are excluded in order to ensure the scientific boundary will result in a sustainably managed basin, consistent with the October 2015 final court order (as depicted in the qualified map submitted in Section J.1 of this application). The proposed basin boundary effectively encloses an area at ground surface beneath which the Paso Robles Formation and windblown sand deposits taper to a negligible thickness (less than about 40 feet) or pinch out entirely against basement rocks (Yates and Wiese, 1988). Within this boundary is a contiguous groundwater reservoir capable of furnishing a significant supply of groundwater to wells or storing a significant amount of water. The basin area excludes Holocene-age alluvial deposits and active dune sands that are directly underlain by bedrock, which have a restricted subsurface hydraulic connection to the basin. The pre-Holocene aquifers include older (stabilized) dune sand deposits, the Paso Robles Formation, and the Careaga Formation. The discussion of the lateral boundaries of the alluvial aquifer or aquifers that form the groundwater basin and the definable bottom is shown on page 2, Description of Lateral Basin Boundaries and Definable Bottom (§ 344.10(a)) section of the Proposed Final Los Osos Valley Groundwater Basin Boundary Modification Request Technical Memorandum (Technical Memorandum). The Technical Memorandum is provided in Attachment E.1.

Attachment(s):

• Attachment J.1_Qualified Map.pdf (919.6kB) Uploaded on 03/28/2016 at 06:00PM
• Attachment E.1 Los Osos Basin Boundary Modification Technical Memorandum.pdf (8.5MB) Uploaded on 03/25/2016 at 04:25PM

F. Notice and Consultation

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

See Attachment F.1.

Attachment(s):

• F.1 Affected Agencies and Affected Systems.pdf (280.7kB) Uploaded on 03/25/2016 at 01:17PM

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

The local agencies and public water systems were identified through the geospatial information system (GIS) on the San Luis Obispo GeoWorks System. The County uploaded the Bulletin 118 groundwater boundary map and the local agencies/public water systems to GIS. The local agencies/public water systems overlying the Los Osos Groundwater Basin ("affected basin") were identified. This list matches the records of the County Environmental Health Services Department (EHS), who updates the public water system list with current information and as defined in Section 116275 of the California Safe Drinking Water Act, which is in Part 12, Chapter 4 of the California Health and Safety Code.

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.

See Attachment F.3.

Attachment(s):

• Attachment F.3_Summary of Consultations with Affected Agencies and Affected Systems.pdf (9.1MB) Uploaded on 03/31/2016 at 04:05PM
• F.3 Correspondence per 343.10 (d) - Status of Request.pdf (9.8MB) Uploaded on 04/06/2016 at 04:51PM

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.

See Attachment F.4.

Attachment(s):

• Attachment F4_Summary of all Public Meetings_Proposed Basin Boundary.pdf (18.7MB) Uploaded on 03/31/2016 at 04:05PM

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.

See Attachment F.5.

Attachment(s):

• Attachment F.5 All Comments Received_Proposed Boundary Modification.pdf (1.9MB) Uploaded on 03/25/2016 at 01:28PM

H. Local Support

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

See Attachment H.1.

Attachment(s):

• Attachment H.1 Information Provided to Affected Agencies and Affected Systems.pdf (9.1MB) Uploaded on 03/28/2016 at 06:14PM

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 Attachment H.2.

Attachment(s):

• Attachment H.2_Resolutions and Letters of Support from Affected Agencies and Systems.pdf (7.1MB) Uploaded on 03/31/2016 at 04:06PM

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

See Attachment H.3.

Attachment(s):

• Attachment H.3 Comment.pdf (1.2MB) Uploaded on 03/28/2016 at 11:23AM

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.

See Attachment I.

Attachment(s):

• Attachment I_Hydrogeologic Conceptual Model.pdf (8MB) Uploaded on 03/25/2016 at 05:21PM

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.

A qualified map of the lateral boundaries of the aquifer that defines the basin is provided in Attachment J.1. The lateral boundaries from the technical study is based on the best available scientific data with the exceptions of five minor areas. These five areas are excluded in order to ensure the scientific boundary will result in a sustainably managed basin, consistent with the 2015 final court order (as depicted in the qualified map submitted in Section J.1 in this application).

Attachment(s):

• Boundary Modification TM 032516 FINAL.pdf (8MB) Uploaded on 03/31/2016 at 03:50PM
• Attachment J.1_Stamped Qualified Map.pdf (941.6kB) Uploaded on 03/31/2016 at 03:50PM

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.

The technical study provides subsurface data that demonstrates the vertical thickness and relevant physical properties of the alluvial aquifer or stacked series of alluvial aquifers is discussed in the Technical Information for Scientific Modification (§344.14) section, starting on page 12 of the technical memorandum. A copy of the Los Osos Valley Groundwater Basin Boundary Modification Request Technical Memorandum, dated March 2016, is provided in Attachment J.2. The technical study provides the basis for the proposed boundary modification request and is supported by the best available scientific data.

Attachment(s):

• Attachment J.2 Los Osos Valley Groundwater Basin Boundary Modification Request Technical Memorandum.pdf (8MB) Uploaded on 03/25/2016 at 05:12PM