San Luis Obispo County - 3-008 LOS OSOS VALLEY

San Luis Obispo County - 3-008 LOS OSOS VALLEY

A. Applicant Information

Requesting Agency Information
Agency Name: San Luis Obispo County
Address: County Government Center, Room 206
City: San Luis Obispo Zip: 93408
Work Phone: (805) 781-5252 Cell Phone:
Email: pwd@co.slo.ca.us Fax:
Revision Request Manager Information
Person Name: Catherine Martin
Address: County Government Center
City: San Luis Obispo Zip: 93449
Work Phone: 805-781-5275 Cell Phone:
Email: cmmartin@co.slo.ca.us Fax:
 

B. Description of Proposed Boundary Modification

  1. Boundary modification for the Los Osos Valley Groundwater Basin (3-8) in San Luis Obispo County.
    • Scientific External
  2. 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.
    • 3-008 LOS OSOS VALLEY
  3. There are no new or consolidated basins proposed.

C. Initial Notification and Combination of Requests

  1. Yes
    Local Agency Potential Basin(s)/Subbasin(s)
    San Luis Obispo County 3-008 LOS OSOS VALLEY
    3-008 LOS OSOS VALLEY
  2. No

D. Required Documents for All Modifications

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

E. General Information

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.

F. Notice and Consultation

See Attachment F.1.
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.
See Attachment F.4.
See Attachment F.5.

H. Local Support

All requests for boundary modification must include the following:
See Attachment H.1.
See Attachment H.2.
See Attachment H.3.

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:
See Attachment I.

J. Technical Studies for External Scientific Modifications

Requests for a scientific modification must include a document containing information that demonstrates the extent of the aquifer. Provide the following:
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).
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.
Created on 03/25/2016 at 8:59AM, last modified on 09/21/2018 at 10:07AM and page generated on 10/17/2018 at 2:02PM