Twenty Mile Creek Watershed Plan

The Twenty Mile Creek watershed is the second largest watershed within the jurisdiction of the Niagara Peninsula Conservation Authority, and it is located in the City of Hamilton, and the Regional Municipality of Niagara including the Town of Lincoln, Township of West Lincoln, and Town of Grimsby. The total drainage of the watershed is 291 square kilometres. The Twenty Mile Creek watershed contains 5 subwatersheds including the main branch of Twenty Mile Creek, North Creek, Sinkhole Creek, Spring Creek, and Gavora Ditch. Individual restoration strategies have been prepared for each of the subwatersheds to protect the unique characteristics of each system.

The headwaters of the main branch of Twenty Mile Creek originate in the former municipality of Glanbrook, and eventually the creek outlets to Lake Ontario at Jordan Harbour. Several Areas of Natural and Scientific Interest (ANSI) are protected throughout the main branch including the Jordan Harbour/Ball's Falls ANSI. Ball's Falls Conservation Area is also located in this portion of the Twenty Mile Creek Watershed. Several regionally significant wetlands and numerous Environmentally Significant Areas (ESAs) are also located in the Spring Creek subwatershed. The land use in the North Creek subwatershed is predominately rural/agricultural in nature. Therefore, specific restoration and best management practices are required to create new riparian and wetland cover to enhance water quality. The Sinkhole Creek subwatershed contains several sites of known karst topography. Karst areas are underlain by soluble rocks and are characterized by sinkholes, depressions and underground drainage. Originating from a series of agricultural drains, Gavora Ditch is unique because it is the only watercourse in the watershed that flows through a quarry.

The unique environmental character of the subwatersheds has resulted in an assortment of issues related to water resources, fish and aquatic habitat, natural heritage resources, urban development, and communication. The watershed issues, which were derived from public input and past studies, were used to form a set of watershed objectives that guided the development of subwatershed restoration strategies and an implementation plan.

The subwatershed strategies include sites for riparian, wetland and upland habitat restoration that have been derived from detailed restoration suitability mapping. In addition, project opportunities on private and public lands have been identified such as erosion control, and shading to reduce water temperatures in the headwaters. Special studies including policy tools and urban water conservation programs have also been proposed. The implementation plan identifies responsible stakeholders for each recommended management action. The recommended management actions have been prioritized and include riparian, wetland and upland restoration and creation to enhance water quality, fish habitat and recreation; specific policy tools including municipal and regional official plan amendments; outreach and communication for various aspects of water resources management; and research and monitoring programs to obtain additional data from which the Twenty Mile Creek Watershed Plan can be updated and revised every 5 years.