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File #: 2019-1793   
Type: Consent Calendar Item Status: Agenda Ready
File created: 12/5/2019 In control: Sonoma County Water Agency
On agenda: 1/6/2020 Final action:
Title: Engineering and Design Services for Headworks Rehabilitation Project
Department or Agency Name(s): Sonoma Valley County Sanitation District (Director
Attachments: 1. Summary Report, 2. Agreement

To: Board of Directors, Sonoma Valley County Sanitation District

Department or Agency Name(s): Sonoma County Water Agency

Staff Name and Phone Number: Carlos Diaz  547-1956

Vote Requirement: 2/3rd

Supervisorial District(s): First




Engineering and Design Services for Headworks Rehabilitation Project



Recommended Action:

Recommended action

In an ongoing effort to replace aging infrastructure and ensure operational reliability:

A)                     Authorize Sonoma County Water Agency’s General Manager, acting on behalf of Sonoma Valley County Sanitation District, to execute an agreement with HDR Engineering, Inc. for engineering and design services through December 31, 2022 in the not-to-exceed amount of $370,000.

B)                     Authorize Sonoma County Water Agency’s General Manager to amend the agreement provided amendments do not cumulatively increase the total cost to Sonoma Valley County Sanitation District by more than 10 percent, while retaining authorities under Resolution 04-0547, and do not substantially change the scope of work.

(2/3rd Vote Required)(First District)



Executive Summary:

Sonoma Valley County Sanitation District (District) needs to replace critical mechanical equipment within the headworks unit process at its wastewater treatment plant (WWTP). The headworks represents the first step in treating wastewater within the WWTP and contains mechanical screening and washing presses responsible for removing large solids from the waste stream to protect downstream equipment and processes. The existing headworks equipment is reaching the end of its useful life and requires routine and significant maintenance. The Headworks Rehabilitation Project (Project) includes design, environmental review, and construction to upgrade and replace the existing headworks equipment at the District’s WWTP. The proposed agreement is for engineering design of the Project.




District’s WWTP is located in southeastern Sonoma County just south of the City of Sonoma, and receives and treats wastewater from a service area including the City of Sonoma and incorporated communities in the Sonoma Valley, including Glen Ellen, Eldridge, Agua Caliente, Fetters Hot Springs, Boyes Hot Springs, El Verano, Temelec, Vineburg, and Schellville.  District provides wastewater collection, conveyance, and treatment to an existing population of approximately 36,000 people.


District’s existing headworks facility is responsible for mechanical screening of raw wastewater inflows and provides the first line of defense in removing solids from the waste stream and reducing solids loading to downstream wastewater unit processes and protecting mechanical equipment from damage.

Screened materials are washed and pressed to reduce water content for improved solids handling.  The existing mechanical screens and washing press were last replaced in 2000 and are approaching the end of their useful life causing excessive needs for repairs and downtime interrupting normal operations at the WWTP.  Furthermore, District currently has only a single washing press so no redundancy is available in the event of equipment malfunction.

The Project includes replacing the existing mechanical screens and washing press equipment with new equipment, including finer mechanical screening, which will further reduce solids loading on downstream equipment and unit processes, and adding redundant wash presses to increase operational resiliency.


The Project involves the design and installation of three new mechanical screens, three new washing presses, and associated upgrades to mechanical piping and electrical and controls equipment.



On May 17, 2019, Sonoma County Water Agency, on behalf of District, issued a Request for Statements of Qualifications (RFQ) to 36 firms.  The RFQ was also posted on the Sonoma Water and County of Sonoma Purchasing Department websites.


The 22 firms listed below submitted Statements of Qualifications (SOQs):

1.                     ADKO Engineering, Inc., Roseville, CA

2.                     Allana Buick & Bers, Inc., Palo Alto, CA

3.                     BC Engineering Group, Santa Rosa, CA

4.                     Bellecci & Associates, Concord, CA

5.                     Beyaz & Patel, Inc., San Diego, CA

6.                     BKF Engineers, Santa Rosa, CA

7.                     Brelje & Race Consulting Engineers, Santa Rosa, CA

8.                     CSW/Struber-Stroeh Engineering Group, Inc., Petaluma, CA

9.                     ERM-West, Inc., Walnut Creek, CA

10.                     GEI Consultants, Rancho Cordova, CA

11.                     HDR Engineering, Inc., Folsom, CA

12.                     InfraTerra, Inc., San Francisco, CA

13.                     LEE & RO, Inc., City of Industry, CA

14.                     Mott MacDonald, San Ramon, CA

15.                     Prunuske Chatham, Inc., Sebastopol, CA

16.                     Questa Engineering Corporation, Petaluma, CA

17.                     Schaaf & Wheeler Consulting Civil Engineers, Santa Rosa, CA

18.                     Summit Engineering, Inc., Santa Rosa, CA

19.                     TJC and Associates, Inc., Walnut Creek, CA

20.                     Watercourse Engineering, Inc., Davis, CA

21.                     Woodard & Curran, Walnut Creek, CA

22.                     ZFA Structural Engineers, Santa Rosa, CA


The following criteria were used to evaluate each firm:

A)                     Thoroughness of SOQ

B)                     Professional qualifications and demonstrated ability to perform the work

C)                     Exceptions to standard terms in the sample agreement


Based on the evaluations, all respondents were selected for the list of qualified consultants.


HDR Engineering, Inc. was selected given their prior experience, qualifications, and demonstrated ability to perform similar work. Their qualifications exhibited the most experience with similar types of wastewater treatment plant projects.


District may seek to amend or enter into subsequent agreement(s) with Board approval if required, relying upon this competitive selection process, after the preliminary or initial work is completed for the Project.



Under the proposed agreement, Consultant will provide engineering design services including, but not limited to, design, drafting, specification preparation, and assistance during bidding and construction for the Project.


The cost of services will not exceed $370,000; the term end date is December 31, 2022.


The agreement includes two options for District to extend this agreement for a period of one year each by providing written notice to Consultant thirty days in advance of the expiration date of the agreement and of the first extension option.


Prior Board Actions:



Fiscal Summary


FY 19-20 Adopted

FY20-21 Projected

FY 21-22 Projected

Budgeted Expenses




Additional Appropriation Requested




Total Expenditures




Funding Sources




General Fund/WA GF












Use of Fund Balance








Total Sources





Narrative Explanation of Fiscal Impacts:

Budgeted amount of $370,000 is available from FY 2019/2020 appropriations for the Sonoma Valley County Sanitation District Construction Fund.  No additional appropriation is required.


Staffing Impacts:




Position Title (Payroll Classification)

Monthly Salary Range (A-I Step)

Additions (Number)

Deletions (Number)















Narrative Explanation of Staffing Impacts (If Required):




Agreement with HDR Engineering, Inc.


Related Items “On File” with the Clerk of the Board: