Salsipuedes Creek Capacity Enhancement & Restoration Project

Project Overview

(This photo is of Salsipuedes Creek – East Lake & College Rd.) Taken in December 2012 by Martin Enrique Garcia.

Santa Cruz County Zone 7 Flood Control and Water Conservation District has been planning the Pajaro River Bench Excavation project for five years.  Last year the county constructed the first phase of the project and the second and last  phase is scheduled to be constructed this year. Public Works and Utilities staff has  been working with the County to investigate the feasibility and benefit of performing a  similar project within the Salsipuedes Creek flood control channel.

Staff has completed a preliminary investigation of the benefits of a bench excavation project. It was determined that excavating and enlarging the channel will increase the channel’s flow capacity, lower the flood stage water surface elevation and reduce flood stage channel velocities, all beneficial effects that collectively reduce the risk of levee overtopping and flooding.

Staff from the City and County met with the US Army Corps of Engineers, the federal agency charged with jurisdiction of the Salsipuedes Creek and Pajaro River flood control channels in order to receive early feedback with regard to permitting the project.Corps staff presented the process for securing permits necessary for a bench excavation project along the creek. The process requires preparation of 70% complete design plans for the project and a hydraulic bank stability assessment. This analysis is required to provide the Army Corps assurances that the proposed sediment removal project will not compromise the stability of the creek banks. The plans and the stability analysis would be submitted to the Army Corps of Engineers along with an application for permission to modify and enlarge the channel.

Staff has solicited a proposal from Northwest Hydraulic Consultants, Inc. (NHC) to perform this work. NHC has been contracting with the County for many years to perform all of the hydrologic and hydraulic engineering work related to the Pajaro and Salsipuedes flood control channels. This includes preparing estimates of the flow volumes for different flood stages, periodically determining hydraulic capacities of the two channels which vary from the year to year due to deposition of sediment or erosion within the channel, as well as other flood related engineering work.

NHC performed the design and plan preparation of the County’s two Pajaro River Bench Excavation projects. Based on their past experience and their performance of previous work on the hydraulic and hydrologic character of the Pajaro River and Salsipuedes Creek, staff is recommending NHC as the most experienced and cost effective choice for this project.

Next Steps - In addition to completing a submittal to the Army Corps of Engineers, the 70% complete improvement plans would be the basis for an environmental review document for complying with the California Environmental Quality Act, and applying for the environmental permits from the five state and federal regulatory agencies required for the project. The design plans and the construction cost estimate included in the scope of services would be the basis of a grant application staff is exploring which could fund the construction of the project.

The steps for implementing the full project include:

  • preparation of the 70% complete plans and bank stability analysis
  • application for permission to modify the channel from the Army Corps of Engineers
  • preparation of the environmental review document
  • application for the various regulatory permits the project requires
  • completion of the plans and specifications necessary for bidding the project
  • securing funding for the construction of the project

The County Zone 7 engineering staff has expressed their support and intention of sponsoring the subsequent steps necessary for implementing the project, but has told City staff that their work load and previous commitments to the Phase 2 of the Pajaro River Bench Excavation project has prevented them from taking the work proposed by this agreement. Staff is recommending proceeding with this phase of the work now in order to maintain progress towards the construction phase of this effort.

If you have questions regarding this project, please contact Tom Sharp, Senior Engineering Associate at 768-3076.

 

This entry was posted on Monday, April 1st, 2013 at 11:06 am and is filed under City Manager, City of Watsonville, Community Development, Homepage News, Library, Parks & Community Services, Public Works . You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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