Recommendation
Staff recommends that the Mayor and Council award the water quality and tank study services to Hazen and Sawyer in the amount of $191,632 via the Master Contract #08-08 (Category K-Water Distribution System Analysis).

Discussion
Project Description
This study will assess chlorine residuals in the distribution system and storage tank, and identify capital and/or operational changes needed to ensure chlorine residuals are maintained at an acceptable level while simultaneously complying with the EPA Stage 2 Disinfection By-Products Rule (Stage 2 DBP R). The Study was recommended by the 2008 Water Master Plan and the Initial Distribution System Evaluation briefed to the Mayor and Council on February 11, 2008. It also will examine recent events of low residual chlorine in the City's distribution system and provide recommendations.

Water quality samples will be collected and tested within our distribution system and utilized to calibrate an existing computer model. The model will be used to analyze the quality of the water in the City's current distribution system.

Background
The new Stage 2 DBPR promulgated by EPA on January 4, 2006 requires that systems minimize the exposure of their water consumers to Disinfection By-Products (DBP’s). DBP’s are a suspected carcinogen and are formed when disinfectants (used to protect consumers from microorganisms in the water) come into contact with naturally occurring organic matter in the water. To address this the EPA has set specific limits on the concentration of DBP’s allowable in a distribution system. In order to achieve these limits the City will have to minimize the use of chlorine added at the Water Treatment Plant which negatively impacts the systems ability to maintain chlorine residuals, especially in areas that are subject to residual decline during the summer months. In their briefing to the Mayor and Council on February 11, 2008, staff discussed the implications of the Stage 2 DBPR on the Water Treatment Plant and introduced the water quality issues associated with this regulation with respect to the tuberculated pipes currently in the distribution system. The City will be required to comply with this regulation by October 1, 2013.

This study will combine field sampling and computer modelling to identify critical system operations where improvements will be needed to maintain chlorine residuals at acceptable levels while simultaneously meeting Stage 2 DBPR. The study will identify capital and/or operational changes needed to strike the balance between maintaining adequate chlorine residuals and minimizing disinfection by-product formation.

Low chlorine residuals have recently been identified in the City's distribution system. This study will identify the causes and operational/capital improvements to alleviate these problems. It will examine factors including water quality entering the system, water age within the storage tanks and the distribution system, and tuberculation of unlined cast iron pipes. While the low chlorine residuals are of concern, they are being managed by increasing the concentration of chlorine added at the Water Treatment Plant and fire hydrant flushing. While this ensures that the water is safe for consumption, it is operationally cumbersome and diverts staff resources away from other tasks and is not considered a long-term solution.

Mayor and Council History
This is the first time this item has been brought before the Mayor and Council. The Mayor and Council awarded Master Contract #08-08 at its October 22, 2007 meeting.

Procurement Information
A request for quote/proposal was requested on July 11, 2008 from Hazen and Sawyer, of Baltimore, Maryland under Master Contract #08-08 (Category K - Water Distribution System Analysis). Hazen and Sawyer has developed a hydraulic model and a water age model of the City's distribution system as part of the Water Master Plan Project (Invitation for Bid #28-06 awarded by Mayor and Council its May 22, 2006 meeting). These models are critical components in analyzing water quality in the system and take considerable time and money to set up, as such, it was determined to use Hazen and Sawyer to perform the water quality and tank study for the City. A meeting was held and attended by Hazen and Sawyer and City staff on July 29, 2008 in order to ensure that the firm had a clear and full understanding of the City's requirements. The quote/proposal was received on August 20, 2008 for $191,632.

At its October 22, 2007 meeting, the Mayor and Council awarded Master Contract #08-08 to various firms for architectural and engineering services in the aggregate amount not to exceed $1,000,000 through June 30, 2008 with the option to extend for four additional one-year periods. All firms under Master Contract #08-08 have been renewed through June 30, 2009. Consistent with that contract award, any individual task that exceeds $100,000 is to be presented to the Mayor and Council for approval prior to the Purchasing Department issuing a Purchase Order.

Fiscal Impact
Adequate funds are available in the Water Tank Assessment CIP project, 210-850-7A34.

Next Steps
Upon Mayor and Council approval the Purchasing Division will issue a Purchase Order to Hazen and Sawyer consistent with the pricing structure, terms and conditions of Master Contract #08-08 (Category K). Work is anticipated to begin in September 2008 and continue for one year.

Department Head:



Craig Simoneau, P.E.; , Director of Public Works
Approved on: 08/29/2008

City Manager:

Scott Ullery, City Manager
Approved on: 09/02/2008