San Lorenzo River Levee Burrowing Rodent Mitigation Project

The City of Santa Cruz Public Works Department is seeking a contractor to implement a burrowing rodent management program on the San Lorenzo River Levees. This program is anticipated to be a multi-year effort to manage the burrowing rodent population and manage the impacts of burrows in the San Lorenzo River Levees. Burrowing rodents pose a threat to levee stability and management of the burrowing rodent population is needed to proceed with FEMA certification.

The burrowing rodent management program will consist of identifying burrows, which may involve weed whipping for visibility by the contractor, mitigating active burrows and grouting existing burrows after mitigation. The selected contractor shall use an RC 206ES Rodent Control compressor or equivalent to mitigate burrows by fumigation. Fumigation shall be completed by a qualified contractor or sub-contractor with a valid California Structural Pest Control Board License and registered with the County of Santa Cruz Agricultural Department. The contractor will survey for and flag active burrows.

Following the fumigation the burrows shall be filled with grout and meet the following requirements:

• 9 parts cement to 1 part bentonite mixed with water to achieve 8-10 inches slump.
• Low pressure injection of flowable grout with shutoff valve to avoid overfilling burrow hole. Backfill injected burrow hole with dirt.
• Use of sediment control BMPs to hold back spillage at the lowest elevation of the riverbank.
• Work areas will be cleaned and devoid of concrete debris
• Each mitigation effort will include a submittal detailing the total gallons of grout pumped into each zone (See attachment A)

Location: Specified zones along the San Lorenzo River levees from Highway 1 bridge to the trestle bridge located by the Santa Cruz Boardwalk parking lot

• Water side: Upper 20 ft of the water side slope as measured from the edge of the paved levee path or to top of rip rap armoring (whichever is less)
• Land side: From edge of paved levee path to levee toe

The City of Santa Cruz was incorporated in 1866 and formed its current charter in 1948. It is governed under a Council/Manager form of government. A Mayor and six Council members set policy for the City and a City Manager serves as chief administrator of those policies. The City is located on the coast, 75 miles south of San Francisco on the northern edge of the Monterey Bay. It encompasses 15.8 square miles with cultural and ethnic diversity among its population of 65,000. Santa Cruz is part of the National Marine Sanctuary and is a popular tourist destination owing to its beaches, surf culture, and historical landmarks.

The City provides a full range of municipal services and facilities including a recreational wharf, public golf course, over thirteen hundred acres of open space, full beach services, refuse management, law enforcement, fire protection, and water and wastewater utilities. The City is also host to University of California Santa Cruz, the Santa Cruz Harbor, and the Santa Cruz Beach Boardwalk amusement park.

The San Lorenzo River levees were constructed in 1959 as the main component of a large-scale cooperative flood control project between the City of Santa Cruz and the United States Army Corps of Engineers (USACE). The City of Santa Cruz (City) is seeking to certify the levee system as meeting the FEMA criteria outlined in Title 44, Section 65.10 of the Code of Federal Regulations (44 CFR 65.10). The City has retained MBK Engineers (MBK) to provide program management to oversee the engineering evaluation and identify any remaining items or other actions deemed necessary to complete FEMA certification of the San Lorenzo River levee system. MBK has identified burrowing rodents as a threat to levee stability and mitigation of the borrowing rodent population is needed to proceed with FEMA certification.