Title
a. Receive a report regarding replacement of tidal gates on Elkhorn Road; and
b. Direct RMA to work with the CAO to prioritize capital project funding allocations to accomplish completion of emergency repairs.
(Board Referral: 2017.27)
Report
RECOMMENDATION:
It is recommended that the Board of Supervisors:
a. Receive a report regarding replacement of tidal gates on Elkhorn Road (Board Referral: 2017.27); and
b. Direct RMA to work with the CAO to prioritize capital project funding allocations to accomplish completion of emergency repairs.
SUMMARY:
This request came via a Board referral from District 2. The County has been asked to address an issue with a missing tide gate that is located on the end of a culvert under Elkhorn Road. This gate went missing during the 2017 winter storms. There are seven gates in this area that help drainage from Carneros Creek to the Elkhorn Slough. There is a long history with these tide gates, but in summary, the culvert is part of the public road and the flap gates were added by private owners.
County has agreed to assume lead for permitting and constructing this repair. Elkhorn Slough Foundation is assisting to make the case for an emergency need.
DISCUSSION:
Monterey County was made aware of this situation around July by Elkhorn Slough Foundation (ESF). It has taken a few months to iron out the responsible party. Since these gates are private (neither a County nor Water Resource Agency facility), it was not identified by either agency during the events. ESF made reference to the gate going missing during the 2017 winter storms (February 2017), but that is not verifiable. ESF is also making the claim of urgency/emergency due to upstream effects of no gate to regulate water flow.
RMA has identified three possible options:
1) Plug Option: This option is a stopgap measure to better control of salt water through the pipe with the missing flap gate. It involves placing a wooden/metal plug on the pipe with the missing flap gate. To hold the plug in place a concrete block(s) or large rip rap would be placed against the plug. The cost for this measure we estimate to be about $25 K. This measure would be temporary until a permanent solution is developed, engineered, funded and constructed.
2) Temp gate option: This option involves installing a temporary gate on pipe with the missing flap gate. A temporary flap gate would be retrofitted onto the existing pipe. The cost for this option needs to include detail review of the pipe to determine the extent of the damage and determining the most cost-effective way of fastening the temporary flap gate. This option will involve plugging and dewatering the area around the pipe. The cost for this option is estimated to be $250 K, provided the pipe is still sound and environmental impacts are not an issue at this location. Given the dewatering and work in the water, regulatory permits are likely to be required.
3) Permanent gate option. This option involves a complete review of the pipes to determine the extent of the corrosion of the pipes and the flap gate connections. This review will determine the most cost-effective way of fastening more permanent flap gates to the pipe. This option will involve plugging and dewatering the area around the pipes to better assess the pipes. The cost for this option is estimated to be $750 K, provided the pipes under the road are still sound and environmental impacts are not significant at this location. Given the dewatering and work in the water, regulatory permits are likely to be required.
Staff’s preference would be to complete the permanent repair so it is done. If we have equipment to install a temporary gate, it seems to staff that it would be better to do that work once and just replace the permanent gate. Alternatives to repairing the gate include a temporary flange (plywood) or a plug. The plug would reduce flood flows through this area, and we do not want to jeopardize the road facility from flooding.
OTHER AGENCY INVOLVEMENT:
In addition to working with Elkhorn Slough Foundation, RMA reached out to the regulatory agencies: US Army Corp of Engineers (USACE), US Fish and Wildlife Service (USFWS), State Department of Fish and Wildlife (CDFW), California Coastal Commission (CCC), and Regional Water Quality Control Board (Water Board). We requested if we could get emergency permits to replace the gate. Initial responses indicate that some agencies do not view this as an emergency project due to the timing so far removed from the storm events last winter. CCC has said that they would assume jurisdiction over this area, meaning that they would process any coastal development permit, not the County. A phone conference is being scheduled for Monday December 11th. We are hoping all of the regulatory agencies will participate so we can reach conclusion on a preferred alternative and process path (emergency or not).
FINANCING:
This project is not in the RMA work plan and we have not identified a funding source for this project. If funding becomes available, we would need to go to the BC, CIC and Board to appropriate the funds and include the project in the work plan. However, RMA will work with the CAO Office to identify and allocate capital funds for this emerging need.
BOARD OF SUPERVISORS STRATEGIC INITIATIVES:
The Project will fill a need to provide safe recreational activity for the regions youth through the provision of new infrastructure on a public/private partnership basis. Participation in these recreational activities will contribute to the overall health of the community.
Mark a check to the related Board of Supervisors Strategic Initiatives
X Economic Development
__Administration
X Health & Human Services
X Infrastructure
X Public Safety
Prepared and Approved by: Carl Holm, RMA Director, x5103
Attachments:
Attachment A - Vicinity Map