participation and apprenticeship from local personnel and resources in each step of the process. As a result, a threefold plan was drafted: 1. Design a drainage master plan. 2. Recruit and train a local construction crew. 3. Coordinate the effort and commitment from CNG, WFN and CIMA+ representatives towards a work schedule that ensured construction materials, equipment and machinery required each year were designed, purchased, shipped (and properly stored) on site by air or sealift, in time to maximize the construction period. THE DRAINAGE MASTER PLAN CIMA+ was mandated to design a new storm sewer, and an outfall pipe to the Great Whale River. This system was designed to alleviate the flooding problem next to the primary school. While proceeding, it became clear that a different plan would be required to address the water accumulation problems occurring at other places in the community. At the onset, CNG and WFN were called upon to assess the need to surface the streets of Whapmagoostui with asphalt pavement, as in the neighbouring community of Kuujjuarapik. The decision was made in favour of asphalt surfacing, and impervious surfaces runoff coefficients were used for the street surfaces in the calculation of flow rates. Because of the community’s flat land surface, it became necessary to consider the use of multiple outlets and conveyance infrastructure with greater hydraulic capacity. Piping systems were therefore added to the existing ditch system. To minimize pipe trenching depth and width, the use of detention chambers was considered to create hydraulic brakes. These underground chambers were also a means to transfer excess water to underground equipment that would otherwise create flooding above ground. It was found that these chambers also contributed to sediment control before discharge into the environment. The community’s wish was to opt for the construction of traditional paved streets with concrete curbs. This meant constructing a conventional storm sewer
WFN recruited local personnel to form a construction crew that would, in time, qualify to operate the required machinery and equipment for trenching, backfilling, laying pipes, etc.
system with underground piping and mulations at various locations within catch basins bordering the curbs. The the community. use of detention chambers remained the The resulting plan was a carefully preferred element for the system to help engineered combination of conventional reduce flooding and surface water accucontinued overleaf… Waste Water products plus NMac 4.65 x 4.65.pdf 1 1/24/2018 7:37:09 AM
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