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1. Catchment Facts

General Geography

  • The Rideau River flows through the heart of the Middle Rideau and is a focal point for residents and visitors to the area. It extends from the outlet of Lower Rideau Lake at Poonamalie (where there is one dam and one lock) to Burritts Rapids (where there is also a dam and lock), at which point it enters the Lower Rideau on its way to Rideau Falls. The Rideau River is also an integral part of the Rideau Canal National Historic Site of Canada and is a significant tourist attraction which draws boaters, cottagers, and campers to the area
  • Smiths Falls, Merrickville and Burritts Rapids are the main urban settlements in the Middle Rideau subwatershed. The Rosedale Creek catchment is predominantly rural in character with agriculture being the main land use. Settlement areas include Nolan’s Corners and Rosedale
  • Parks Canada staff manage water levels for recreational purposes along the Rideau Canal/Waterway that flows by the catchment, ensuring 1.5 metres of draft during the navigation season. In this managed system, water levels on the Rideau Canal are manipulated by operation of numerous dams. In the Middle Rideau subwatershed, Parks Canada staff operate 9 dam and lock complexes with 13 locks for a fall of 36.2 metres over 35.6 kilometres. Water levels are maintained as close as possible to set objectives through the May to October navigation season. The levels are lowered through the rest of October and into November and held at the winter levels until the spring freshet in late March or early April naturally increases inflows to the system. To reduce the impact of the higher flows in the spring, the amount of snow water equivalent, forecast rain, ice cover, flows and levels are assessed and the dams in the Middle Rideau reach are operated accordingly to quickly pass as much water as possible. In late April and early May, the dams are gradually closed and water levels are brought up to be ready, once again, for the navigation season

Physical Geography

  • All of Rosedale Creek Catchment and the rest of the Middle Rideau Subwatershed primarily resides within the Smith Falls Limestone Plain, which in this area, happens to consist of older Paleozoic quartz sandstone and dolostone of the March Formation. A small section of the Oxford Formation dolostone however, is also found within the southern part of the catchment. The bedrock in the catchment is overlain by a thin veneer of glacial sediment, referred to as ‘drift’ that is generally less than a metre in thickness; although there are organic deposits underlying the two main wetlands in the catchment and clay lining the creek’s corridor. A geologic fault likely transects the southern part of the catchment
  • One Hundred percent of the catchment lies within the Township of Montague
  • Rosedale Creek catchment drainage area is 64 square kilometres and occupies about eight percent of the Middle Rideau subwatershed and one percent of the Rideau Valley watershed

Vulnerable Areas

  • Lower reach of Rosedale Creek is subject to a flooding hazard during the regional storm flood (the 100 year flood). Surveys and studies undertaken in accordance with provincial standards have determined that the 100 year flood elevation in this area ranges from 107.9 metres above mean sea level at the upper, mapped extent of the regulation limit above Rosedale Road South to 104.3 metres above mean sea level at its outlet to the Rideau River
  • The Assessment Report developed under the Ontario Clean Water Act identifies the upper bedrock aquifer underlying all of the catchment area as a Highly Vulnerable Aquifer, although, where sediments are thicker in a local area, the vulnerability would be less. The southern half of the catchment lies within part of the Wellhead Protection Area for the Merrickville municipal wells; related provincial policies apply


  • The Township of Montague consists of scattered residential and agricultural development, mostly along traditional transportation routes and in areas of good agricultural capability. The hamlet of Rosedale, with some more recent subdivision development is the area of densest rural residential development in the catchment. Commercial and industrial development is very limited outside the settled areas and there are no major employers within the Township
  • Recent years have seen an increase in residential lot creation throughout the catchment, after a lengthy period of stagnant population. Montague's relative proximity to Ottawa and ease of access, as well as relatively affordable land are thought to have contributed to this. Interestingly, most recent severances have been in the more rural forested settings, as opposed to along major transportation corridors or established built communities. As such, site specific environmental impact studies and development conditions have often accompanied approvals. Lot sizes have often also been larger than the 'standard minimum' of an acre. Montague's population had one of the highest rates of increase among Lanark County municipalities between 2006 and 2011

Conditions at a Glance

Water Quality

  • Surface chemistry water quality rating in Rosedale Creek is “Fair” at both monitoring sites (2009 to 2014). Site ROS-01 (County Rd. 43) has improved from a “Poor” to a “Fair rating from 2003-2008 to 2009-2014, while site ROS-02 (Rosedale Rd. South) remains unchanged. Elevated bacterial counts and nutrient concentrations from inflows of nutrients (from private septic systems, agricultural, commercial, residential surface runoff) are a feature of Rosedale Creek and decreased nutrient and bacterial counts are needed to improve the overall health of the creek
  • Instream biological water quality conditions at the Rosedale Creek sample location range from “Very Poor” to “Fair” from 2003 to 2014 (using a grading scheme developed by Ontario Conservation Authorities in Ontario for benthic invertebrates) with an overall benthic invertebrate water quality rating of “Very Poor” to “Fair” determined for this period

Instream and Riparian

  • Overall instream and riparian condition for the Rosedale creek catchment as assessed by the stream characterization and headwater drainage feature assessment programs show that Rosedale Creek and its tributaries are in generally good condition. The majority of the system has a healthy riparian corridor with low levels erosion along the system. Instream diversity of aquatic habitat is somewhat variable with moderate levels of riffle habitat and low levels of pool habitat. Several opportunities were identified on tributaries of Rosedale Creek to enhance riparian habitat conditions.  One weir and multiple beaver dams were identified as potential migratory obstructions for fish passage along the creek at the time of the survey
  • The Rosedale Creek catchment has 25 species of recreational and bait fish and is classified as having a cool/warm water thermal guild that supports the Rosedale Creek/Rideau River fishery
  • In the Rosedale Creek catchment, the riparian buffer (30 m. wide strip along the shoreline of all lakes and streams) is comprised of wetland (63 percent), crop and pastureland (20 percent), woodland (12 percent), settlement areas (three percent) and roads (two percent)

Land Cover

  • Dominant land cover is woodland (36 percent) followed by crop and pastureland (31 percent), wetland (27 percent), settlement areas (four percent) and roads (two percent). From 2008 to 2014, there was an overall change of 143 hectares (from one land cover class to another). Within the catchment, major change is a result of the conversion of woodland to crop and pastureland. A slightly smaller proportion of change is also associated with crop and pastureland emerging as young woodland. Another factor of change is the conversion of crop and pastureland and woodland to settlement
  • Woodland cover in the catchment has decreased by 29 hectares between 2008 and 2014 and interior forest habitat has decreased by 27 hectares
  • Wetland cover has decreased by one percent (56 ha) from pre-settlement times to the present and now occupies 36 percent of the catchment area


  • Approximately 720 to 760 in-use water wells with provincial records in this catchment. While most water wells are used for domestic water supply, in this catchment, several are also used for public and agricultural water supplies, monitoring or cooling
  • Two bedrock aggregate licenses occur in or partially within the catchment and there is one sand and gravel pit license in the catchment
  • There is one Environmental Compliance Approval for an institutional sewage works and one for municipal air emissions and a Permit to Take Water has been issued in this catchment for commercial dewatering

Catchment Care

  • Thirty stewardship projects have been completed with assistance from the RVCA’s Rural Clean Water and Tree Planting Programs (see Section 5 of this report for details)
  • Rosedale Creek surface water quality has been monitored by the RVCA through its Baseline Monitoring Program since 2003. The surface water quality at sites ROS-01 and ROS-02 is monitored once a month from April to November
  • RVCA has been collecting benthic invertebrates in Rosedale Creek at the Matheson Drive site since 2003
  • RVCA conducted a fish survey along Rosedale Creek in 2014
  • RVCA completed the stream characterization survey on Rosedale Creek in 2014, working upstream to the headwaters from the mouth of the creek where it empties into the Rideau River taking measurements and recording observations on instream habitat, bank stability, other attributes and preparing a temperature profile
  • RVCA completed 18 headwater drainage feature assessments at road crossings in the Rosedale Creek catchment in 2014. This protocol measures zero and first order headwater drainage features and is a rapid assessment method characterizing the amount of water, sediment transport, and storage capacity within headwater drainage features
  • A watershed model developed by the RVCA in 2009 was used to study the hydrologic function of wetlands in the Rideau Valley Watershed, including those found in the Rosedale Creek catchment
  • The Township of Montague has land use planning policies and zoning provisions - on lake capacity, water setbacks, frontage and naturalized shorelines and wetland protection - and use site plan control to implement these policies and provisions. Together with RVCA, the Township works with landowners on a case by case basis to achieve net environmental gains (particularly with respect to shoreline vegetation protection and rehabilitation) through the application of shoreline best management practices. Through the land-use planning process, the Township, RVCA and agencies request conditions of approval to ensure that development and redevelopment is appropriate for the property, impacts on neighbours are minimized (particularly on very small lots) and development setbacks for the shoreline are maximized
  • Development in and adjacent to the Provincially Significant Wetlands in the catchment (North Montague Swamp, Pinery Road, Rideau River Part 1, South Mud Lake) are subject to Ontario Regulation 174-06 (entitled “Development, Interference with Wetlands and Alterations to Shorelines and Watercourses”) that protects the hydrologic function of the wetland and also protects landowners and their property from natural hazards (flooding, fluctuating water table, unstable soils) associated with them