Recommendation
Staff recommends that the Mayor and Council award the modification to rider Bid #IFBCI4651A07 to Humphrey & Son, Inc. of Laurel, Maryland in the not-to-exceed amount of $180,000 to investigate and repair sanitary sewer pipes and manholes in the vicinity of I-270 and approval to accelerate the appropriation of the Sewer Rehab - Watts Branch CIP project (220-850-7B45).

Discussion
Background:
The Clean Water Act includes regulations covering sanitary sewer system operations to eliminate sanitary sewer overflows (SSOs). An SSO is wastewater (sewage) leaving a conveyance pipe, pumping station or treatment facility without treatment and discharging into streams, storm drainage systems or onto open ground. SSOs cause damage to the environment and are a public health and safety risk. SSOs occur when there is a blockage in a pipe or wastewater facility, or when the wastewater flow exceeds the conveyance or treatment capacity. It is estimated that there are 40,000 SSOs throughout our nation every year.

The Department of Public Works Maintenance staff responded to a sanitary sewer overflow (SSO) in January 2008 between Bullards Park and I-270 in the Watts Branch Sewershed. After the blockage was relieved, staff "TV'd" the subject pipes and found several defects. Defects found during this investigation were as follows: tree roots protruding into pipe joints, leaking pipe joints (groundwater flowing into the pipe), a service connection in disrepair and concrete debris that was wedged into a pipe joint. Damage from the concrete debris was the immediate cause of the SSO, and probably occurred during highway construction work in 1986.

Tree roots and leaking pipe joints are evidence that this section of the sewer system has on-going infiltration and inflow (I&I). Infiltration occurs when high groundwater seeps into the sewer pipes through cracks and holes in the pipeline, pipe connections, and manholes. Inflow occurs when stormwater directly enters the sewer system through roof drains (connected to the sewer system), manhole covers, or illicit storm drain connections to the sewer. I&I increases the flow of extraneous water in a wastewater collection system. Decreasing I&I decreases the amount of extraneous flows in our sewer system, and thus reduces the City’s operating expenses, and may avoid capital expenses associated with replacing pipe to increase capacity for future development. There are additional environmental benefits gained by replenishing the groundwater and decreasing the amount of flow requiring treatment. Also, cleaning and lining sewer pipes will help prevent overflows.

Project Description:
The rehabilitation process involves cleaning the inside of a sewer pipe by pressure washing. A cutter also is used to eliminate roots and debris at pipe joints. Once the pipe is clean inside, a resin-coated liner is inserted into the pipe via manholes. Once the liner has been fit into the pipe, the liner is cured and hardened by high temperature stream. The service connection will be excavated and repaired.

This project will investigate a total of 4,050 linear feet of sewer pipe and cleaning and lining at least 1,300 linear feet of sewer pipe and 1 manhole in Watts Branch. The contractor will inspect the sewer lines with a TV camera before and after the liner installation. Installing a liner within the sewer system will seal all interior cracks and leaking pipe joints. Another benefit of pipe and manhole lining will be to eliminate the invasion of tree roots into the pipe system. Tree roots cause maintenance issues such as damaging the pipes or blocking the flow of sewage that may lead to spills or overflows.

Included in this modification is the investigation of the other three I-270 sanitary sewer crossings. These crossings vary in pipe diameter between 8 and 15-inches. The not-to-exceed contract amount does not include rehabilitation of the other crossings. If additional rehabilitation work is warranted, staff will request an increase to the sewer rehab contract.

Reference:
Humphrey & Sons, Inc. has performed utility work for the City with good results, including the upgrade of the Horners Lane Sewer Pump Station, the Fallsgrove Pressure Reducing Valve, and prior sewer lining work in Twinbrook.

Mayor and Council History
Mayor and Council awarded initial bid on January 28, 2008. This is the first amendment to that award.

Public Notification and Engagement
Residents will be notified individually via neighborhood advisories at least two weeks before work begins on cleaning and lining pipelines.

Procurement Information
WSSC awarded Bid #IFBCI4651A07 for Sanitary Sewer Main and Manhole lining thru a competitive process. The Bid contained unit pricing for various sewer rehabilitation techniques, including cleaning and lining.

Mayor and Council previously awarded rider Bid #IFBCI4651A07 to Humphrey & Son at their January 28, 2008 general session meeting to install sanitary sewer pipe and manhole liners in the Cabin John and Rock Creek sewer basins.

In accordance with Section 17-71 of the City code, Cooperative Procurement; (b) The City may contract with any contractor who offers goods, services, insurance or construction on the same terms as provided other state or local governments or agencies thereof who have arrived at those terms through a competitive procurement procedure similar to the procedure used by the City.

Fiscal Impact
Funding ($180,000) will be transferred from project #220-850-3D45, Blue Plains Wastewater Treatment into project #220-850-7B45, Sewer Rehab - Watts Branch for the sewer system investigation and rehabilitation. Revised CIP project sheets are provided (see Attachment 1, New Blue Plains and Sewer Rehab - Watts Branch sheets).

Next Steps
Purchasing to issue a modification to the contract to Humphrey & Sons, Inc. The repair will begin immediately following contract approval. Work is anticipated to continue for one month.

Attachments


Attachment 1: New Blue Plains and Sewer Rehab - Watts Branch sheets
(Revised CIP Sheets)

Department Head:



Craig Simoneau, P.E.; , Director of Public Works
Approved on: 02/06/2008

City Manager:

Scott Ullery, City Manager
Approved on: 02/06/2008