Conservation area chosen as wetland to battle flooding

Saltfleet Conservation Area may become home to one of four proposed wetlands as part of a Hamilton Conservation Authority strategy to control flooding and erosion along Stoney and Battlefield creeks.

Deputy chief administrative officer Scott Peck said a class environmental assessment study chose the new First Road East park and three other locations from among nine potential sites in upper Stoney Creek because they were best suited for the purpose.

If all goes as hoped, work on creating a marsh at the conservation area would start in 2019, with those at the other locations to proceed in stages if the authority is able to acquire the land, he said at an open house on the study.

Peck said the authority plans to excavate about a quarter of the 72hectare conservation area for the wetland in a bowl-shaped field between the entrance at the top of a hill and the Dofasco 2000 Trail to the north. The swamp will hold 220,000 cubic metres of water, a “substantial amount” that will reduce flooding during major storms and augment creek flows during droughts, he said.

Peck said the authority is no longer considering asking the city to raise the height of First Road East and will instead use berms to contain water where necessary.

While design details remain to be determined, the wetland will be about two metres deep and potentially have a boardwalk or adjacent trail linking to a trail to the Devil’s Punch Bowl and the Dofasco 2000 Trail, he said.

“Generally speaking, you don’t want a wetland any deeper than two metres because then it really stops being a wetland at that point,” Peck said. “What you really want to do is kind of bring it up to that level and then slowly (allow) for it to dissipate through evapotranspiration or into the ground or into the watercourse.”

The other three locations are on a farm by the corner of Ridge Road and First Road East; just east of Third Road East, south of the Dofasco 2000 Trail; and midway between Tapleytown and Fifth roads, south of Green Mountain Road.

The study estimates the four wetlands will cut Battlefield and Stoney creeks’ erosive flows by about one-third and remove 36 of 46 buildings from flood risks during a 100-year storm. Peck said the timing of the three other marshes is dependent on acquiring the necessary portions of properties on a willingbuyer, willing-seller basis.