Home
All Requests
Map ViewerSanta Barbara County Water Agency - 3-014 SAN ANTONIO CREEK VALLEY
Santa Barbara County Water Agency - 3-014 SAN ANTONIO CREEK VALLEY
A. Applicant Information
Requesting Agency Information
|
|||
|---|---|---|---|
| Agency Name: | Santa Barbara County Water Agency | ||
| Address: | 130 E. Victoria Street, Ste #200 | ||
| City: | Santa Barbara | Zip: | 93101 |
| Work Phone: | (805) 568-3542 | Cell Phone: | |
| Email: | fcrease@cosbpw.net | Fax: | (805) 568-3444 |
| Revision Request Manager Information
|
|||
|---|---|---|---|
| Person Name: | Matt Naftaly | ||
| Address: | 3760 State Street | ||
| City: | Santa Barbara | Zip: | 93105 |
| Work Phone: | 805 308-8529 | Cell Phone: | |
| Email: | mnaftaly@dudek.com | Fax: | |
B. Description of Proposed Boundary Modification
-
Boundary modification for the San Antonio Creek Groundwater Basin in Santa Barbara County.
-
- Scientific External
- Jurisdiction Internal
-
The San Antonio Creek Groundwater Basin as included in Bulletin 118 extends west from the headwaters of San Antonio Creek to the Pacific Ocean. The requested modification, along with minor modifications along the basin perimeter, would establish the western boundary approximately 7 miles east of the ocean at the west side of the Barka Slough. The basin is truncated by a geologic bedrock barrier at that location forcing groundwater to the surface creating the slough and effectively eliminating the potential for sea water intrusion. Based on previous studies, geology, and topography, the proposed boundary more accurately includes areas of recharge and water use in the basin. Most significantly, the area west of Barka Slough is separate from the basin to the east, contains little potential for water storage, and includes very little water production, based on a review of Well Completion Reports from this area. Successful management of the basin is a community issue requiring both participation by all of the relevant land and water users and an accurate understanding of the physical setting and geohydrology of the basin. Recognizing the true boundary of the basin and collaborating with users of the adjacent basins will allow for the development of a meaningful groundwater management plan and participation by the appropriate parties.
-
- 3-014 SAN ANTONIO CREEK VALLEY
-
There are no new or consolidated basins proposed.
C. Initial Notification and Combination of Requests
-
Yes
Local Agency Potential Basin(s)/Subbasin(s) Santa Barbara County Water Agency 3-014 SAN ANTONIO CREEK VALLEY -
No
D. Required Documents for All Modifications
In review of CEQA, Santa Barbara County has made the determination that Basin Boundary adjustment does not constitute a "Project" under CEQA and is therefore not subject to CEQA. Given that the Basin Boundary adjustments do not meet the "Project" definition, there is no requirement to seek or make a finding for a Statutory or Categorical Exemption, nor provide any other CEQA treatment at all.
E. General Information
The San Antonio Valley is approximately 30 miles long by seven miles wide. It is cradled between the Solomon-Casmalia Hills to the north, the Purisima Hills to the south, the Burton Mesa to the west and the westernmost flank of the San Rafael Mountains to the east. The watershed is approximately 130 square miles and the Groundwater Basin within the Valley is about 110 square miles. Average annual rainfall within the basin is about 15 inches. The basin is adjacent to and abuts the Santa Maria Valley groundwater basin to the north and the Santa Ynez Uplands Basin to the east and south.
The San Antonio Valley is shaped by an eastward plunging syncline containing the deposits comprising the groundwater basin. The Paso Robles formation and alluvium are the most common material within the Groundwater Basin. Consolidated rocks lie below the basin deposits but surface about seven miles east of the Pacific Ocean, forcing groundwater to the surface, and creating a wetland area known as Barka Slough which denotes the western end of the Groundwater Basin.
The lateral boundaries of the basin are defined by four features:
1. The San Antonio Creek watershed, delineated using a USGS 3-second Digital Elevation Model (DEM)
2. Surface outcrops of water-bearing geologic formations, as identified in georeferenced Dibblee geologic maps
3. The boundary of the Adjudicated Santa Maria Groundwater Basin
4. The boundary of the Santa Ynez River Water Conservation District (SYRWCD).
The proposed revised boundary was created assuming that the San Antonio Creek watershed (i.e., topographic drainage divides) constituted an ultimate bounding feature. Within the watershed, if the contact between water-bearing geologic formations and consolidated, non-water-bearing formations occurs downslope of the watershed boundary, the area upslope of that contact was not included in the Basin. On the western end of the basin, the boundary traces the furthest extent of surface outcrops of the Careaga Sand.
In areas where the basin as defined by the watershed and geology overlapped slightly with existing neighboring jurisdictions (i.e., Santa Maria to the north and the SYRWCD to the south), the small areas within the neighboring jurisdictions were excluded from the proposed San Antonio basin.
The definable bottom is the base of the Careaga Sand, which is the oldest water-bearing formation present in the Basin. The base of the Careaga Sand ranges from approximately 800 feet above sea level (and approximately 700 feet below ground surface) in the upper reaches of the watershed to 1,500 - 2,000 feet below sea level in the vicinity of the valley floor, and is slightly above sea level in the vicinity of the Barka Slough.
F. Notice and Consultation
See Attachment
The requesting agency and consultant representatives have worked on water and groundwater related issues in the basin for multiple decades. Therefore, they are familiar with all of the interested local agencies. In addition, the requesting agency reviewed participant and stakeholder lists from multiple ongoing programs within the basin including conservation programs, purveyor agency meetings, and groundwater basin studies. Finally, an internet search was conducted to identify any additional State or Federal agencies that may have an interest in the basin.
Each affected agency was contacted as part of all stakeholder outreach activities. Some attended the Basin boundary Modification public workshop and other meetings. In addition, each was sent a letter explaining SGMA, the Basin Boundary Modification process, and specifically how to provide comments to the requesting agency or DWR. Many affected agencies in this basin are also members of the Consultation Committee for the ongoing San Antonio Groundwater Basin technical study and were apprised on several occasions of the proposed modification as part of those meetings (see F4 below).
See Attachments
See attachements
G. General Existing Groundwater Management
All requests for jurisdictional modification pursuant to Section 342.4 MUST include responses to the following questions.
The Santa Barbara County Water Agency, in conjunction with the USGS, is currently conducting a technical study of the San Antonio Creek Valley Groundwater Basin with the goal of better understanding the basin geology and hydrology. In addition, the study will identify areas where additional groundwater recharge may be possible. As part of the study, a Consultation Committee was formed to facilitate coordination with local stakeholders and pass on local knowledge regarding the basin. This group provides a natural starting place for issues that affect the basin as a whole and has provided a venue for the emerging SGMA concerns such as basin boundary modification. This group will be actively involved as SGMA moves forward in the San Antonio Basin. Because minor areas of the proposed basin intersect adjacent jurisdictions within other basins, there has been information exchange, discussion, and collaboration with the entities responsible for those jurisdictions which will foster ultimate collaboration on shared issues. The City of Santa Maria, Twitchell Management Authority, and Santa Ynez River Water Conservation District have all engaged with the Santa Barbara County Water Agency on the SGMA (see attached correspondence between adjacent basin entities, G2).
Historically, resource planning at the watershed level was conducted with the development of the San Antonio Creek Coordinated Resource Management Plan prepared by the Cachuma Resources Conservation District and completed in 2003. Vandenberg Air Force Base (VAFB) has coordinated and cooperated with basin interests in regard to water supplies and other resources issues. For example, VAFBs purchase and importation State Water in the late 1990s allowed them to reduce pumping from the San Antonio Creek aquifer to the benefit of all of the basin users.
By making use of those existing and historic resources and venues, sustainable groundwater management and the requirements of SGMA can be efficiently implemented. The study now underway will provide the necessary technical information regarding the aquifer and the associated group of stakeholders provides a logical place to initiate collaboration. In addition, stakeholder lists and other information compiled for the basin boundary modification request has fostered the education and outreach efforts necessary for groundwater management.
The San Antonio Creek Valley Groundwater Basin is immediately adjacent to two other groundwater basins as defined in Bulletin 118. In each case, the proposed boundary modifications will not prevent or make more difficult the sustainable management of the adjacent basins.
To the north of the San Antonio basin is the Santa Maria Valley Groundwater Basin. The basin has been adjudicated since 2005 and as such is not subject to the full requirements of SGMA. In accordance with the adjudication, the basin is subject to oversight and reporting by a Water Master and is managed through the court process.
The sustainable management of the Santa Maria Groundwater Basin will not be negatively impacted by the proposed San Antonio Basin boundary modification because the proposed boundary will not encroach into the adjudicated area. In those areas where the adjudicated Santa Maria Basin overlaps with the San Antonio watershed, the area of overlap has been excluded from the proposed modified San Antonio Basin These areas of overlap are minor and do not contain significant areas of recharge or water use (see Figure D3). In addition, Santa Barbara County has coordinated the boundary modification request with the Twitchell Management Authority (TMA), the entity that is responsible for complying with the terms of the adjudication.
To the south, the proposed San Antonio Basin shares a border with the the administrative jurisdiction of the Santa Ynez River Water Conservation District (SYRWCD). Similar to the situation on the northern border, the small areas where the SYRWCD overlaps with the San Antonio watershed have been excluded from the proposed modified San Antonio Basin. These areas of overlap are minor and do not contain significant areas of recharge or water use (see Figure D3).
To the east, the San Antonio Groundwater Basin shares a border with the Santa Ynez River Valley Groundwater Basin, and the proposed boundary is defined by topographic divides and geologic outcrops (see Figure D3). The proposed boundary extends the eastern edge of the San Antonio basin into the Bulletin 118 Santa Ynez Basin, because the San Antonio watershed extends slightly eastward of the Bulletin 118 San Antonio boundary. No negative impacts to sustainable management are expected from this modification. In fact, because the proposed San Antonio boundary in this eastern area is based on topographic drainage divides, this modification will more accurately reflect the true divide between the San Antonio and Santa Ynez basins, and thus should improve management of groundwater resources in both basins.
Additionally, the area to the east of the proposed boundary is a "white area" within the jurisdiction of the Santa Barbara County. However, the entity that is preparing to comply with SGMA in the Santa Ynez River Valley Basin as a whole is the SYRWCD. The County has coordinated the basin boundary request with the SYRWCD and will likely be a member of the GSA within both basins. Such coordination will assure efficient sustainable management of both basins.
The attached hydrographs (locations shown on Figure D3) show a general trend of groundwater level decline from the late 1960s to recent times. Conspicuous in each of these is a period of moderate recovery beginning in the late 1990s. The timing of this coincides with a statistically wetter than normal period and also the time at which the VAFB began taking deliveries of State water which allowed them to cut back significantly on extractions from the basin. The basin imbalance has been calculated to be on the order of 9,000 AFY more extraction than recharge on average (See Santa Barbara County 2011 Groundwater Report, May 1, 2012).
The Santa Barbara county Water Agency developed an approved CASGEM monitoring plan for the San Antonio Creek Valley Groundwater Basin. This plan was approved by DWR in July of 2014 and revised February of 2016. In addition, the Santa Barbara County Water Agency has conducted a groundwater monitoring program with the USGS for several decades. Because the proposed boundary modification primarily excludes areas with little or no groundwater and no CASGEM or USGS monitoring wells, there will be no substantial impact to these State programs. Currently, Total Maximum Daily Load requirements are being developed for Chlorpyrifros and Nitrogen. These efforts will not be hindered by the proposed basin boundary modification because the areas proposed to be excluded do not contain significant groundwater or sources of contamination.
H. Local Support
All requests for boundary modification must include the following:
Attached are the letters sent to affected agencies. In addition, there were several communications with entities in bordering basins as described in Section G.
Two letters of support were received from affected agencies and provided as attachments in H1. These are from the Cachuma Resource Conservation District and the Los Alamos Community Services District. There were no comments submitted in opposition.
No opposition to the proposed modification was received.
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:
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:
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:
The proposed modified boundary for the San Antonio Groundwater Basin is primarily based on scientific criteria (i.e., topography and geology), but small adjustments have been made to accommodate the two adjacent administrative jurisdictions: the Santa Maria Adjudicated Groundwater Basin to the north and the Santa Ynez River Water Conservation District (SYRWCD) to the south. Figures D3 and D3-A and Sections G and E have more information on these jurisdictional modifications. In summary, because the impacts that these accommodations will have on sustainable water resource management are predicted to be negligible, it was decided that the most prudent course of action was to include the political boundaries of the Santa Maria Adjudicated Basin and the SYRWCD as bounding features on the proposed modified San Antonio Groundwater Basin. Both adjacent agencies have indicated they have no objections to the proposed modified San Antonio Basin Boundary. It is anticipated that there will be coordination between GSAs in bordering basins on shared SGMA issues and projects, as needed.
