Redcliff Sanitary I-I Investigation

Redcliff, AB

ISL was engaged by the Town of Redcliff (population: 5600) to provide an inflow-infiltration (I-I) investigation to combat issues in the Town's wastewater collection system, which included residential sewer backups.


ISL reviewed previous wastewater system evaluations before constructing and calibrating a varied dry and wet weather MIKE URBAN model. After reviewing the wet weather I-I rates using the model, we performed flow correction routines on the existing flow monitoring data.

Open House

An open house was held to gather historical sewer backup information, and surveys were sent out requesting information about I-I contributors, such as roof leaders, sump pumps and weeping tiles.

Smoke Testing

Smoke testing, in which sections of the sewer system are filled with non-toxic smoke to locate entry/exit points, was implemented to identify other sources of inflow and infiltration.

Complex System

Complex hydraulics and structures, such as split chambers, siphons and lift stations, were present in the system. To model these complicated systems, all sewers, manholes, gravity trunks and forcemains were imported into the MIKE URBAN model individually.

Final Report

A targeted CCTV inspection was completed to assess pipe conditions in critical locations. A comprehensive report detailing all findings and upgrading cost comparisons was completed for the Town.

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