Runoff and Erosion
Spring Freshet 2016
By George Powell, member of WAG Committee
Past articles in “The Watershed News” have endeavoured to bring to the membership our concerns regarding the impact of erosion on the Blue Mountain Watershed. Our involvement in the Townline Creek Assessment Reports has been ongoing since 2007. In partnership with the Nottawasaga Valley Conservation Authority and the Grey Sauble Conservation Authority we monitor water-quality to identify potential impacts from existing and future developments in the Creek’s watershed and to provide recommendations towards mitigating such impacts. Townline Creek is representative of the numerous small Escarpment watercourses that discharge directly into Nottawasaga Bay along its south shore. Sponsorship by Environment and Climate Change Canada started in 2014, allowing this work to continue for at least another year.
Results from sampling (2007-2015) indicate that total phosphorus (TP) and total suspended solids (TSS) are parameters of concern in Townline Creek. Monitoring should be continued in order to identify potential pollution source areas and to track changes in stream condition over time.
We initiated our 2016 monitoring program on March 28 during which over 48mm of rain fell in a 24-hour period throughout the Collingwood area. During extreme wet weather events much can be learned as erosion is significant and very visible.
After the March rainstorm, above, along the shoreline of Nottawasaga Bay, turbidity was noticeable for almost half-a-kilometre offshore. Batteaux Creek, Pretty River, Black Ash Creek, Silver Creek, Townline Creek, Indian Brook and the Beaver River were all highly turbid as they conveyed sediment off the steep slopes into the Bay.
On the north side of Concession 12 at Mission Road in the Town of the Blue Mountains the steep banks are being seriously eroded. The Township has carried out some needed erosion protection within the road easement (note stone in the invert of the ditch).
As can been seen in photo above, undercutting is occurring and will continue until ditch side slopes are vegetated or armoured.
Looking north up Concession 12 at Mission Road, above, note turbidity in runoff coming down the slope
Looking east on Mission Road at Concession 12, above, note vegetated side slopes and clarity in the runoff.
In many cases, on private property, there is little or no vegetation protection on stream banks, as in this case above, where the stream flows directly into a Silver Creek tributary.
Above, Grey County’s reconstruction of Scenic Caves Road in 2015 has made a significant contribution to improving conditions, not only for our cyclists but also in reducing sediment impact on Silver Creek.
Osler Bluff Ski Club is to be commended for its significant investment in reusing ski hill runoff by intercepting it and storing it for snow making in a large pond at the foot of the Escarpment. This results in reduced sediment discharge to Black Ash Creek.
Significant slippages occurred this winter in a steep section at one of our ski clubs, above. After these events and until erosion protection is in place, there is significant sediment runoff. Efforts are needed as soon as possible to prevent further erosion to the ski hill and impact on the watershed.
Above: turbid flooding at a local golf course. There is a concern of potential pesticide runoff as herbicides are used as a preventative measure to control snow mould. Our pesticide monitoring program has demonstrated that pesticides can be transported off golf club property into watercourses. This is a matter we continue to raise with the Ministry of Environment and Climate Change.
Clearview Township is proposing to reconstruct Side Road 26/27 as an alternate all-weather route up the Escarpment when a section of former County Road 91 is turned over to Walker Industries. We are opposing this reconstruction based on the experience we have gained in our monitoring efforts and observations in the watershed.
We hope this update will promote awareness of issues impacting our watershed. Please pass this article on to others you know who can help us in our efforts to “Preserve and Enhance the Blue Mountain Watershed.”