The
Niagara Chapter and their partners have been working to preserve and improve the Twelve Mile Creek watershed, the last remaining spring fed cold water system in the Niagara Region of Ontario.
Threatened by encroaching development, the headwaters of the stream originate in the fast-growing village of Fonthill and wind through agricultural land to Short Hills Provincial Park. Immediately downstream of the Park, the Twelve is completely changed by discharge from the hydroelectric installation that re-routes water from Lake Erie via the Welland Ship Canal, and from there downstream to its outlet in Lake Ontario, it’s a channelized, manmade watercourse that is also home to the famous Henley rowing venue.
Among their several projects to improve the headwaters of Twelve Mile Creek, the Niagara Chapter applied for and received grants totaling over $250,000 from the Trillium Foundation and the Dept. of Fisheries and Oceans to combat the erosion and sedimentation caused by heavy flooding in the clay soils of the headwaters. These flooding events have been exacerbated by runoff from the roofs, parking lots, and roadways being built in and around Fonthill. One of the main projects undertaken with this grant money was the construction of six “wing deflectors” to speed up streamflow and deepen stream at strategic points in Short Hills Park.
Partnered with the Niagara Restoration Council, an NGO that seeks to preserve natural spaces, the Niagara Chapter began the application process for in-stream work in 2016. The permitting process was daunting, as the project would require permits from the
Ministry of Natural Resources and Forestry, the Dept. of Fisheries and Oceans, the Niagara Peninsula Conservation Authority, Ontario Parks, and the Niagara Escarpment Commission. All the permissions were finally in hand by the fall of 2018.
Wing deflectors can be constructed from many materials, but the team decided on ash logs, as the Emerald Ash Borer had provided countless dead ash trees near the site of the proposed work. The logs were cut, hauled, and stacked two deep, embedded in trenches cut into the banks of the stream, protruding about a third to halfway across in a V configuration. The center of the V was filled in with old Christmas trees, soil, logs, and debris, and it is anticipated that sedimentation will further increase the barrier effect. Eventually, the deflectors will create a meander in the stream, increasing its velocity and scouring deep pools on the downstream side. The six deflectors in a sequence should have a major positive effect on erosion while creating habitat.
The work took place over three days in November, with the advantage of a skillful and enthusiastic contractor who was able to get a six-tonne excavator to the site to dig the trenches and haul and place the ash logs. Under the supervision of fluvial geomorphologist and
Niagara TUC member, Ian Smith, the team pinned the logs together with rebar spikes, hand-filled the V created by the logs, and planted live stakes to establish a root network to stabilize the deflectors. The resulting meanders will be monitored over the next several years by the Chapter and students from the Niagara College Environmental Programs to gauge the effects and report back to the granting agencies.
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