Moncton Sewer System Review and Master Plan, Study Area

Project Description
In the late 1990s, various areas within the City of Moncton experienced flooding during heavy rainfall events. The City of Moncton retained Moncton Infrastructure Group (a partnership of five engineering companies from the Moncton area, one of which was Terrain Group) to evaluate the City’s storm sewer system. The goal of the study was to identify the work required to improve the system for optimal performance in a cost-effective manner. The study area included a large portion of the central urban area of Moncton. The watershed areas examined were essentially fully developed, consisting primarily of single-family residential dwellings with some commercial, institutional, and industrial uses. The storm sewer systems fell into one of three categories: combined sewer systems, partially separated systems, and completely separated systems. The watershed area examined was approximately 636.5 hectares (1573 acres) in size. The storm and combined sewer systems assessed by this study totalled over 85 km of pipe, with approximately 1,200 manholes.

Services Provided
The data collection phase of this work included a review of available as-built drawings and an intensive program of site inspections to determine watershed boundaries and field measurements of existing manhole locations, elevations, pipe sizes, and pipe connectivity. The City of Moncton’s Geographic Information System was used to prepare base maps in support of the data collection component of the project. Video inspection records of the existing pipe systems were reviewed to assess the status of the pipes from the perspective of pipe capacity and condition. Following data collection, a computer-based stormwater model was prepared in order to assess system performance and evaluate the effect of various improvement options. The stormwater model was validated by rainfall and pipe flow measurements and enabled the City to evaluate the impact of future development in the watershed. The model was used to carry out an analysis of the stormwater systems in the study area. Improvement options were identified and tested, and a final recommended improvement program was established. This portion of the study included a cost-benefit analysis of the various options in order to select the most cost-effective approach. The improvement options were placed in a recommended construction sequence on the basis of providing maximum benefit for expenditures to be undertaken.