The Pipeline

It’s Revision time for RWRD’s Engineering Design, Specifications and Details for Construction Manual
By Francisco Gallindo and Irene Barriga 

The Pima County Regional Wastewater Reclamation Department (PCRWRD) is requesting a public review of the Pima County Regional Wastewater Reclamation Department Engineering Design Standards, Specifications and Details for Construction 2021.  These revisions simplify and clarify the requirements of the Sewer General Notes, new RWRD Standard Details, revisions to scour detail, and minor editing of the 2016 Pima County RWRD Engineering Design Standards. 
RWRD’s Standards Committee, comprised of members of the engineering and construction community, and County staff, have worked on the revisions of the design and construction standards as part of their annual work plan. These standards are to go into effect by December 2021, and apply to ALL new submittals of tentative subdivision plats, development plans, landscaping plans, paving and grading plans, public sanitary sewer connections, and public sanitary sewer extensions. 

The Design Standards for Public Sewers in Pima County have three primary goals: 
To attain a 100-year Service Life for sanitary sewer conveyance facilities prior to rehabilitation or replacement 
To access and maintain sanitary sewer conveyance facilities in a cost-effective manner
To keep roots, grease and other obstructions out of sanitary sewer conveyance facilities 

The Design Standards provide the minimum criteria for the design of Public Sewage Conveyance facilities in Pima County. It is not intended that these standards be blindly applied in every application. There may be strong technical reasons why a particular standard is not appropriate for a given situation. In unique circumstances, creative engineering design, based on sound engineering principles, may meet the intent of the Standards. 

The current Standards Committee Members include: 
Francisco Galindo – RWRD Engineering 
Lorenzo Hernandez – RWRD Field Engineering
Adam Bliven – RWRD Conveyance Capital Improvement Unit
Regina Beem – PSOMAS
Brian Janski – Hunter Contracting Co.
Corey Thompson – Rick Engineering Company, Inc.
Bruce Paton – Rick Engineering Company, Inc.
Support Staff – Charlie Suckow and Irene Barriga - RWRD Engineering

Previous Standards Committee Members and Contributors:
Carol Johnson – RWRD Engineering
Mike Redmond – RWRD Conveyance
David Logue – RWRD Field Engineering
Bill Baker – Baker & Associates
Craig Cannizzaro – Westland Resources
Warren Thompson – Stantec 

To date, RWRD staff reviewed comments received from the engineering community. Comments received were incorporated into the standards for clarifications and enhancement.  Significant changes from the 2016 version to 2021 version include:
1. Removal of the formatting standards based on stakeholder input
2. Use of C900 PVC Replacing DIP in certain instances – washes, dry utility separation, velocity >10fps
3. DIP interior lining to be CIPP
4. Temporary cleanouts for -phased subdivisions
5. Use of 4’0 manholes for 12” and 15” pipes – limited application – one incoming/outgoing
6. Stabilized surfaces width reduction from 16’ to 12’
7. RWRD detail no. 113 – scour protection detail
8. Internal drop manhole – deleted external drop manhole
9. Depth required of sewers – 4’ to 3’ without variance. Case-by-case basis review

The Standards Committee’s upcoming meeting schedule is comprised of the following presentations and discussions.
Release of RWRD standards draft to review – Friday, October 1, 2021 through Sunday, October 31, 2021
RWRAC meeting – Thursday, October 28, 2021
Board of Supervisors meeting – Tuesday, December 21, 2021
Implementation of Standards – Wednesday, December 29, 2021

For more information and to review the 2021 Engineering Design Standards sections, visit the Pima County RWRD Design Standards, Specifications & Details webpage at:
The following links include the section cover pages.
Standard Specifications and Details for Construction
Engineering Design Standards
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