Christie Lake Pond Decommissioning and Fish Habitat Improvement
The Christie Lake reservoir, constructed in 1971, is used for flood control, flow augmentation, and recreational purposes. Within the Conservation Area, seven fishing ponds were also constructed in the 1970’s as recreational fishing areas with the ponds stocked annually. The ponds are located on existing watercourses typically in areas with groundwater inputs. These ponds are physically separated from Christie Lake by perched culverts and drop structures. As the ponds approach the end of their use for fishing, HCA considered the potential for removal and returning the systems to natural stream corridors.
Map of Christie Lake CA pond locations
The online pond systems on the northern shore of the lake have been shown to negatively affect the quality of water entering Christie Lake. On average the online ponds raise water temperatures by 3.75°C before entering Christie Lake, with the exception of pond 4 which has substantial groundwater inputs. Over the years, the ponds have in filled with sediment, become rich with nutrients leading to algae growth and in recent times with increases in summer temperatures support the production of Cyanobacteria.
Based on the degradation of the ponds and minimal recreational uses, HCA initiated the Christie Ponds Decommissioning and Fish Habitat Improvement Project in late 2013. The goals of the project are to improve access and fish spawning habitat for Northern pike, reduce water temperature increases associated with standing water, and improve water quality by restoring natural channel processes and increasing buffers to watercourses. To complete the design work for these ponds, HCA commissioned the services of a Fluvial Geomorphologist to classify the flow and sediment regime of the watercourses and provide a design for pond removal and stream rehabilitation.
Restoration on the ponds 1-5 began winter 2014 and completed winter 2015. Restoration works within the ponds 1-3 included the re-establishment of fish passage, natural channel and installation of perched wetland features connected to the streams during high flow events becoming inundated and accessible by fish. The purpose in developing this connectivity is to create spawning and nursery habitat for Northern Pike. The perched wetlands will also provide habitat for amphibians, turtles and benthic invertebrates by including woody debris features for refuge areas as well as basking sites where suitable.
Ponds 1, 2 and 3 Pre-construction Ponds 1, 2 and 3 Post-construction
During winter 2015, HCA initiated restoration works on Pond 4 and 5. Pond 4 is strongly influenced by groundwater inputs and so the desired outcome for this location is to produce a highly productive spawning site. Pond 4 already had great spawning potential, although fish passage was impeded by a vertical pipe. Based on this, HCA decided there was little channel establishment required however, re-establishment of fish passage and improvement of wetland features were implemented to enhance habitat connectivity.
Pond 4 Pre-construction looking upstream Pond 4 Pre-construction with vertical pipe
Pond 4 during construction Pond 4 Post-construction
The restoration works completed for pond 5 were similar to pond 4; with the focus on the creation of a seasonally flooded wetland for propose of Northern pike spawning and nursery habitat. Perched culvert was replaced with a larger culvert to facilitate fish passage and bioengineering features (LUNKER, root wads and sweeper logs) were also incorporated into the design to create habitat for various fish and wildlife species and stability on site.
Pond 5 Pre-construction looking upstream Pond 5 Pre-construction perched culvert
Pond 5 during construction Pond 5 Post-construction
The restoration works for both Ponds 4 and 5 took approximately 7 days to complete. Within Pond 4, a total of 178 meters of natural channel was connected to downstream habitat along with a total of 4,131 sq. meters of wetlands were developed. Within Pond 5, a total of 160 meters of natural channel was restored to facilitate access from downstream habitat along with a total of 700 sq. meters of wetlands were developed. As part of the restoration area fish habitat was improved to facilitate fish passage and create spawning and rearing habitat for targeted fish species. This restoration area will promote a sustainable native fishery within Christie Lake which will improve health of the fishery (bring back top predator species, Northern pike) as well as improve aquatic species diversity through the creation of the wetland features. These features will promote greater fishing opportunities and enjoyment of the natural environment. In addition to the fish habitat improvement works, HCA staff will be planting wetland and riparian vegetation in late spring (May 2016). Riparian, upland and aquatic vegetation planted to help promote habitat function, species diversity, stream bank stabilization and minimize potential for invasive species to establish.
Funding for the project was provided by DFO Recreational Fisheries Conservation Partnership Program, Hamilton Conservation Foundation, RBC Bluewater Project and TD Friends of the Environment. Post monitoring program has been created and will begin spring 2016. The monitoring program will include fisheries and benthic invertebrate assessments, wetland plants species survivability, amphibian surveys and invasive species surveys.
HCA is very proud of this project and is very excited to monitor its ongoing process and success.