Project Description
The original Mill Creek Municipal Drain was constructed in 1956. At that time, the drain terminated at Hwy. 17 and flowed a further 2km through a natural watercourse to its outlet at the Ottawa River. Subsequent years saw significant increases in agricultural activity including clearing of previously forested lands, increased tile drainage, urban development, and the addition of contributing drains.
Increased pressures from upstream drainage in conjunction with poor underlying soil conditions resulted in a significant slope failure on the natural water course section within the village of L’Orignal.
The Township of Champlain tasked Robinson Consultants Inc. with addressing the slope failure as Emergency Work under Section 124 of the Ontario Drainage Act, R.S.O. 1990, and ultimately with full modification and improvement of the Mill Creek Municipal Drain under Section 78 of the Act to incorporate the emergency work and make necessary adjustments for the remainder of the drain. Robinson Consultants Inc. successfully petitioned the Ontario Ministry of Agriculture Food and Rural Affairs for permission to complete the Emergency Work.
Design for the failure area included geotechnical review of the slope failure and adjacent area, drone level LiDAR survey of the failure (conditions were not stable for a standard survey to be completed) and the implementation of specialized geotechnical design incorporating a ballast feature with slope flattening and standard rock protection.
Following the completion of the emergency work, Robinson Consultants Inc. was tasked with preparing an Engineer’s Report for improvement and modification for the full extent of the drain, including incorporating the emergency work. Ensuring sufficient outlet included incorporating as a municipal drain the remainder of the natural watercourse to the outlet at the Ottawa River. Improvements included permanent sediment and erosion control with some deepening and widening of locations restricting flow. Special consideration was required to address the concerns of environmental agencies including the Department of Fisheries and Oceans, Ministry of Natural Resources (acting as the Conservation Authority for this area as it is outside of the jurisdiction of a Conservation Authority), and the Ministry of Environment Conservation and Parks for the protection of Endangered Species.
