In August 2002, the commission instituted a Sewer Inflow/Infiltration Program. Inflow is defined as locations where large amounts of storm water runoff may enter into the sewer collection system. Some sources of inflow include large holes in the collection system, missing sewer cleanout caps, missing manhole covers and household guttering being connected to sewer laterals.
Infiltration is defined as locations where ground water may seep into the sewer collection system. Some sources of infiltration include deteriorating clay sewer laterals, broken or cracked lateral lines and main lines and leaking manholes.
This program involves determining sources of inflow and infiltration and removing such sources as is cost effective. The first step, completed in August and September 2002, involved smoke testing the entire sewer collection system. Some problems identified were gutters connected to the sewer lateral lines, broken or missing sewer cleanout caps, leaking sewer lateral lines and leaking sewer main lines.
The second step involved conducting flow monitoring. This required installing flow meters in selected manholes throughout the collection system to record the flow over a period of 3-4 weeks. This, combined with rainfall data for that period, will be used to determine which sections of the collection system are prone to high levels of inflow and/or infiltration.
The third step involved some light cleaning of the sewer mains and putting a closed circuit camera through selected sections of main to determine the condition of the main as well as any blockages or intrusion of tree roots. This step was completed in April 2003.
The fourth step involves a visual inspection of each manhole and a GPS location for each manhole in the collection system to determine the condition of the manhole. Upon completion of this step a plan can be drawn up listing repairs to be made to the system.
Some residents may also receive letters concerning the condition of their sewer lateral line and the necessary repairs they will need to make.