A Sanitary Sewer Evaluation Survey and Infiltration & Inflow (I&I) Study was completed by the City in December 2009 as an aid in identifying areas that are experiencing or may experience high volumes of I&I. Infiltration is groundwater/storm water that can enter sanitary sewer systems through defective pipe joints and/or broken pipes typically found below the surface. Inflow is water entering the sanitary sewer system from inappropriate connections such as roof drains, yard drains, and domestic sewer cleanouts without caps located on private property. Both of these undesired water sources can be identified through sanitary sewer smoke testing. High volumes of I&I can cause dilution in sanitary sewers which can decrease the efficiency of wastewater treatment or may cause sewer volumes to exceed wastewater treatment plants’ capacities. Many times it may be difficult to distinguish the source of the cause, so the Environmental Protection Agency (EPA) defines the term I&I as combined contributions from both.

This process prioritized the lift station infrastructure and service areas for further investigation.  The study included a GIS-based risk rating system to identify critical line segments based on factors such as infrastructure needing repairs, pipe depth and material. The recommended improvements were ordered and ranked by importance based on the GIS risk rating system, with Project A being the higher priority and Project D being a lower priority.  Rehabilitation efforts for Project A, B and C have been completed.

Project D is identified as the next priority focus.  A Preliminary Engineering Report (PER) for Project D was completed in April 2017 and design was completed in April 2018.  The construction of Project D is separated into two packages due to different construction means and methods required. Package 1 involves cured-in-place and Package 2 requires pipe bursting to rehab the identified wastewater lines.

An Invitation for Bid (ITB) was advertised for Package 1 on April 4, 2018 and April 11, 2018.  Bids were opened on April 26, 2018 and four (4) bids were received for the project.  The following is the bid summary:

The responsible low bidder is Layne Inliner, LLC with a total bid of $2,818,575.  The Engineer's estimate of probable construction cost is $2,650,000. The Consultant along with City staff recommends awarding the contract to the responsible low bidder, Layne Inliner, LLC.

The construction scope of work for Project D is summarized as follows:

• Rehabilitation of approximately 10,850 L.F. of wastewater mains through cured in place lining
• Rehabilitation of manholes with coatings

There is currently $4,814,329 available in CIP WW1601.  The remaining project balance will be used for a construction administration contract with ARKK Engineers for Package No. 1 and construction of Package No. 2.  Package No. 2 will consist of rehabilitation of wastewater lines through pipe bursting methods which is anticipated to be bid in July 2018.

Construction of Package No. 1 is anticipated to begin in July 2018 with 270 calendar days to substantial completion in March 2019.  The City is aware of the potential impacts to residents and will coordinate and communicate as required per City notification policy on construction notifications.  Staff will utilize several measures during construction such as door hangars, mail outs, website updates, etc... in order to maintain open communications with all impacted property owners.  The contractor will also be knocking on doors and placing door hangers as needed.

Staff recommends the City Council authorize the execution of a construction contract with Layne Inliner, LLC in the amount of $2,818,575 for the Collection System Rehabilitation Project D, Package No.1, CIP WW1601.