Bank erosion and the resulting sedimentation of watercourses is not only an issue for water quality, but also can damage or completely destroy fish habitat, and can result in a significant loss of property for the landowner. In a lot of cases bank erosion could have been prevented or slowed by maintaining a healthy riparian area.
Generally, the area within 30 meters of a watercourse is considered a riparian area. A riparian area is considered healthy when it has dense nature and native vegetation (trees, shrubs, and grasses). The vegetation not only provides cover for the watercourse to lower water temperatures and provides fish habitat; but the root system of these plants holds the sediment of the bank stable against the normal force of the water passing by. When a riparian area is healthy, erosion is generally minimal, unless other issues are present within the reach (area) under normal flow conditions. During times when water is high and rushing (spring freshest and large rain events) this vegetation becomes even more important to help prevent erosion and major bank loss.
During September 2015 a large rain event pounded the Belleisle watershed and caused a lot of damage to watercourses, roadways, culverts, and homes. The following summer, the BWC undertook the re-assessment of some of these watercourses to determine the impact of this event had on the watercourses. From these stream assessments the BWC has begun riparian enhancement initiatives in areas that were flagged during the assessments.
A small enhancement project was completed below the Route 124 crossing along Daley Brook. As a result of the rain event, the understory vegetation along this reach was scoured away; as such, the BWC planted some understory vegetation along with some native shrubs within the riparian area.
This site has undergone a huge change as a result of the 2015 storm event. To repair the road damage sustained, the riparian area surrounding the roadway was cleared, filled, and the banks of the brook were hardened with rip-rap. After the road word was complete the riparian area was left with little to no vegetation leaving the brook susceptible to high water temperatures. The BWC began its restoration of this site in 2017 by planting native trees, shrubs, and understory vegetation to provide cover and wildlife habitat. Although, the bank is unlikely to suffer from erosion where it has been hardened, downstream of the rip-rap is now at risk. In 2018, the BWC hopes to continue this restoration by enhancing bank vegetation below the hardened reach.
As a result of the development of the trail a small patch of vegetation was removed. Marsh vegetation was re-established in this area to restore the Marsh back to its natural conditions as part of the overall Belleisle Creek Marsh Trail development project.
At this point, visually the sites looks very similar to pre-planting conditions. When using natural techniques to improve or restore ares, the vegetation must be given time to establish and mature. Once these plants begin to grow and mature they will provide wildlife habitat, erosion control, and improve water quality.
Going forward, the BWC will continue to monitoring and assess our enhancement and restoration sites for plant growth/survival, habitat changes, and signs of erosion; as well as continue stream assessments to determine future restoration sites within the watershed.