Interlake Tunnel - Monterey and San Luis Obispo Counties, California

From CCoWS Wiki
Revision as of 12:27, 9 April 2020 by TedR (Talk | contribs)

Jump to: navigation, search
Image 1. Interlake Tunnel.

A Environmental Topics summary by the ENVS 560/L Watershed Systems class at CSUMB.

This page provides a brief overview of the history, timeline of events, EIR Development, contract documents and county presentations for the proposed Interlake Tunnel.


The primary purpose of the Interlake Tunnel was to redirect water from the Nacimiento Reservoir to the San Antonio Reservoir in efforts to reduce spillage at the Nacimiento Dam. Based on historical data, the Nacimiento River basin produces roughly three times the average flow of the San Antonio River basin. To increase the overall capacity of the system, the Interlake Tunnel could capture high Nacimiento River flows and reroute them to the San Antonio Reservoir.[1]

The Monterey County Water Resources Agency (MCWRA) prioritized the completion of the Salinas Valley Water Project (SVWP) and the Salinas River Diversion Facility before the Interlake Tunnel Project.[2]


The tunnel is designed to be approximately 11,000 feet long and used gravity flow dynamics that has an inflow situated at the Nacimiento Reservoir and an outflow built in the San Antonio Reservoir. The total project is estimated to cost $50 million and could be completed by 2022.

The Monterey County Water Resources Agency (MCWRA) expressed priority in a preliminary environmental review before moving beyond pre-construction tasks. Pre-construction costs are imaged here.

Image 2. Pre-construction Phase costs.

Timeline of Events[3]

In June 2014, the Board of Supervisors of the Monterey County Water Resources Agency (MCWRA) authorized negotiation and execution of a funding agreement between Monterey County and the MCWRA for an amount not to exceed $500,000 for program management, engineering and environmental review of the Interlake Tunnel, said funds to be reimbursed to Monterey County if the Interlake Tunnel is approved and financed; and directed staff to return to the Board of Supervisors in July 2014 with a project status report and information on financial impact to the County in regards to funding the agreement. The Board of the MCWRA also authorized the MCWRA General Manager to enter into the necessary agreements to prepare for and commence environmental review of the Interlake Tunnel in an initial amount not to exceed $500,000 provided funding is approved by Monterey County. Presentation slides for this meeting are found here[1].

On July 1, 2014, the Monterey County Board of Supervisors approved a funding Agreement and approved the use of County funds for the Agreement. The MCWRA has contracted EPC Consultants as the Program Manager and Construction Manager, a legal firm to perform the water rights analysis, and will solicit a qualified environmental firm.

On August 25, 2014, the Board of the MCWRA held a public workshop to provide background information about the Interlake Tunnel and to provide an update of current project activities and accomplishments. The agenda and presentation slides for this workshop are found here[2].

On November 19, 2014, the Board of the MCWRA held a public workshop to provide current feasibility status on the Interlake Tunnel. The agenda, including technical memoradum, and presentation slides for this workshop are found here[3].

On January 15, 2015, MCWRA published an Informational Notice of pending RFP’s for engineering design[4].

On February 26, 2015, MCWRA held a public meeting on the proposed Interlake Tunnel and San Antonio Spillway Modification project. The meeting was held in the Heritage Ranch Conference Room, Paso Robles, CA.

On March 13, 2015, MCWRA published an UPDATED Informational Notice of pending RFP’s for engineering design. This notice contains the RFP schedule.

On April 16, 2015, a RFP pre-proposal meeting was held. The presentation can be found here[5].

On April 28, 2016, a Notice of Preparation/Initial Study (NOP/IS) was circulated, initiating a 45-day scoping period for the Environmental Impact Report. The scoping period concluded on June 13, 2016. The NOP/IS can be found here[6].

On May 16 and 17, 2016, scoping meetings were held. The presentation can be found here[7].

EIR Development[4]

Contract Documents[5]

County Presentations[6]





This page may contain student work completed as part of assigned coursework. It may not be accurate. It does not necessary reflect the opinion or policy of CSUMB, its staff, or students.