Title
Review of Previously Adopted Proclamation of Local Emergency due to the conditions of saltwater intrusion into groundwater sources and inundation near the Moro Cojo Slough, causing conditions of extreme peril to the safety of persons and property nearby.
Report
RECOMMENDATION:
It is recommended that the Board of Supervisors review of previously adopted Proclamation of Local Emergency due to the conditions of saltwater intrusion into groundwater sources and inundation near the Moro Cojo Slough, causing conditions of extreme peril to the safety of persons and property nearby.
SUMMARY:
On November 3, 2015, the Board approved Resolution 15-285 declaring an emergency related to a failure in the flap gate and culvert system underneath Moss Landing Road. This failure has led to saltwater intrusion in the Moro Cojo Slough. The culvert, which provides drainage and typically prevents saltwater from re-entering the system through the flap gate, cannot function as designed, and therefore currently is ineffective. As indicated in the November 3 Board Report, while repairs have been made to the flap gate recent inspections revealed the threat of increased failure throughout the culvert as a whole.
Failure would result in extensive seawater intrusion into the area surrounding the Slough, impacting critical groundwater resources for local residents, including their animals. Prolonged exposure of increased salinity can impact water wells in the immediate area that provide potable water for multiple properties. Impacts to groundwater supplies would affect those who depend on these sources for drinking water.
The Government Code requires that emergency proclamations be reviewed at least once every 30 days until the emergency is terminated. This is the last Board meeting within that 30-day time period. Efforts are still underway for temporary repairs to be made to the culvert system and for these temporary repairs to be maintained while a permanent solution is designed.
DISCUSSION:
The elevation difference between the ocean and the Moro Cojo Slough is typically 4-5 feet at high tide, and can reach even larger spans with the instance of a “King Tide”. This elevation difference, combined with the inability of the culvert to provide effective drainage, results in an additional threat of damage, both to Moss Landing Road and structures located nearby including critical utilities.
Seawater has been detected approximately 4 river miles upstream of Moss Landing Tide Gates. Until recently, the tide gates at the mouth of the Moro Cojo Slough allowed tidal mixing that supported brackish water environment.
The brackish water condition supports populations of federally endangered tidewater goby (Eucyclogobius newberryi) and California brackish water snail (Tryonia imitator), ranked S2 (State Imperiled, CNDDB) to reside in the Slough. Additionally, the freshwater portions of the middle and upper watershed are known to support populations of federally and California endangered Santa Cruz long-toed salamanders (Ambystoma macrodactylum croceum), federally and California threatened California tiger salamanders (Ambystoma californiense), and federally threatened California red-legged frogs (Rana aurora draytonii) as documented in the CNDDC (2015).
The elevated water levels within the slough poses a risk of flooding and threat to nearby homes, agricultural land, and additional sensitive habitats not inundated with seawater. The slough’s increased water level decreases its capacity to take storm water from a 16 square mile tributary area resulting in economic losses due to flooding of homes and productive agricultural land within the Moss Landing.
CAO and WRA will continue to update the Board of Supervisors periodically concerning the emergency and efforts to restore the full functionality of the culvert, protecting against saltwater intrusion into groundwater resources and inundation of the surrounding areas.
OTHER AGENCY INVOLVEMENT:
The mitigation efforts of the foregoing conditions affecting the Moro Cojo Slough include Monterey County Resource Management Agency; Planning Department and Monterey County Public Works Department, Water Resources Agency, Monterey County Health Department - Environmental Health Division, the California Coastal Commission (original jurisdiction for permit authority), Moss Landing Harbor District, US Army Corp of Engineers, US Fish and Wildlife Services, Water Board, and State Fish and Wildlife.
FINANCING:
The prior proclamation of local emergency will impact the General Fund in emergency contracts, engineering services, and overtime costs incurred by WRA, which may be requested for reimbursement from the General Fund at the end of the fiscal year. Continued reporting, as required under the Government Code does not require any additional General Fund contribution.
Prepared by: Approved by:
_____________________________ ______________________________
Sherrie Collins Nicholas E. Chiulos
Emergency Services Manager Assistant County Administrative Officer
Attachment: Resolution 15- 285 (adopted November 3, 2015)