Dredged Stormwater Sediment Finds New Use in Ottawa

Stormwater sediment reused as landscape material

A community in Ottawa eliminated the need to transport dredged stormwater sediment from the Monahan Drain stormwater pond to a disposal site thanks to Bishop Water’s solids management solution. Not only is it simple and reliable, Bishop Water’s approach also provides a cost-effective way to reuse stormwater sediment onsite and comply with the Ministry of Environment and Climate Change’s (MOECC) best management practices for excess soil management, which were updated in 2017.

stormwater sediment bag

For nearly 25 years, the Drain had been receiving stormwater runoff from the nearby community of Bridlewood. Draining and digging out the pond is a costly, time-consuming process to increase storage capacity. Instead, the general contractors for the site began exploring new ways to remove sediment from the Drain to meet the needs of the growing community. Bishop Water’s solids management solution was ultimately selected since it provides a simple, affordable, onsite solution to enable speedy sediment removal and dewatering.

To prepare the site for the dredging and dewatering project, a laydown area was constructed on the west side of the Drain to hold seven, 100-foot-long geotextile containers. As the hydraulic dredge removed stormwater sediment from the pond, a specially selected polymer is used to dose the slurry to accelerate the separation of water from the solids.

The mixture was then pumped into Bishop Water’s high-strength geotextile containers that trapped the solids inside as filtrate was released. Since the dewatering process produced high-quality filtrate, operators discharged it directly back into the Drain without any additional treatment or concern about negative impact to water quality.

Dewatering containers become naturalized berm

Bishop Water’s solids management solution also provides an affordable way to comply with the MOECC’s best management practices for excess soil, which encourages owners and operators to treat, process and reuse excess soil onsite. Once the dewatering process was completed at the Drain, the Geotube® containers were covered with soil to form a berm that’s planted with grasses, shrubs and trees. The naturalized berm now conceals a busy road from view and suppresses road noise from reaching the residential and recreational properties on the other side of the Drain.

stormwater sediment dredging

Not only did the general contractors reuse 2,100 tonnes of stormwater sediment that was removed from the Drain, they also eliminated costs and greenhouse gas emissions that would have been otherwise produced by transporting it offsite.

Learn more about the Monahan Drain Geotube® dewatering project.

Learn more about using Bishop Water’s Geotube® dewatering system for municipal applications.

Contact us to discuss Geotube® dewatering solutions for your stormwater facility.