Comprehensive, Synergistic Stormwater Channel Remediation

Comprehensive, Synergistic Stormwater Channel Remediation
Vegetated channels have years of proven benefits and success. Vegetated channels provide a soft solution to the landscape and allow for water infiltration. Vegetated channels also have cooler discharges than channels with hard armor and riprap. In addition, the vegetation provides filtration of contaminated runoff as well as providing habitat for wildlife.
With the benefits of vegetated channels in mind, this property owner decided to protect their land from erosion and scour by investing in a comprehensive overhaul of the failing stormwater channel system. No modern BMPs were used in the previous channel so property damage and maintenance problems occurred with each large rainfall and snowmelt event. The new synergistic system was engineered to include Erosion Control Blankets, Turf Reinforcement Mats, Scour Protection Mats, Rock Check Dams and Sediment Retention Ponds.
Erosion Control Blankets protected the soil disturbed during construction activity from erosion during rain and wind events. The resulting vegetation reduced the sediment load flowing to the newly established channels. Turf Reinforcement Mats (TRMs) protected the channel soil surfaces, while reinforcing the vegetation root systems so higher shear forces could be withstood. The permissible shear stress capability of the expectant vegetation alone would not have been able to withstand the design flows for the channel, so a TRM was needed. The vegetated channel was designed to carry runoff from the site and prevent the water from forming gullies, which will deposit sediment further downstream.
Scour Protection Mats were used to protect the outflows of stormwater culverts from plunge scour. Rock Check Dams were used to reduce flow velocity within the channel. Lastly, Sediment Retention Ponds were strategically located to collect and help treat stormwater at the site.
This presentation will examine the problem, solutions, and lessons learned over the course of this comprehensive project.