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1.0 Hobbs Drain Catchment: Facts

1.1 General/Physical Geography


  • Ottawa: (32 km2; 100% of catchment)


  • Hobbs Drain Catchment resides within a transitionary area between the Ottawa Valley Clay Plain to the east and the Smith Falls Limestone Plain to the West. The southern half of the catchment is underlain by beach sands and gravels, sand plains and some areas of glacial till. Bedrock lies at the ground surface throughout the northern part of the catchment and is overlain, in areas by organic soils and localized areas of beach sands and gravels
  • In this catchment, bedrock mostly consists of interbedded limestone and dolostone from the Gull River Formation. In addition, a geologic fault may pass through the catchment


  • The ground surface ranges in elevation from approximately 155 masl south of Hwy 7 to approximately 96 masl at the catchment’s outlet

Drainage Area

  • 32 square kilometers; occupies six percent of the Jock River subwatershed, one percent of the Rideau Valley watershed

Stream Length

  • Hobbs Drain and tributaries: 66 km

1.2 Vulnerable Areas

Aquifer Vulnerability

  • The Mississippi-Rideau Source Protection initiative has mapped parts of the southern half of this catchment as a significant groundwater recharge area; and all the catchment as Highly Vulnerable Aquifer. Parts of Wellhead Protection Areas (WHPA) C and D for the municipal wells in Richmond underlie the northern extent of this catchment. In addition, parts of the WHPAs B and C for the municipal wells in Munster Hamlet, underlie part of this catchment near Bleeks Road

Wetland Hydrology

  • 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 Hobbs Drain catchment

1.3 Conditions at a Glance

  • Surface chemistry water quality rating along the Hobbs Drain is “Fair” from 2009 to 2014. The score at this site is largely influenced by occasional high nutrient concentrations, bacterial pollution and metal (aluminum) exceedances (see Figure 2)
  • Instream biological water quality conditions at the Hobbs Drain sample location range from “ Poor” to “Excellent” from 2004 to 2015 (using a grading scheme developed by Ontario Conservation Authorities in Ontario for benthic invertebrates) with an overall benthic invertebrate water quality rating of “Good” determined for this period

Instream and Riparian

  • Overall instream and riparian condition for the Hobbs Drain is unknown

Thermal Regime

  • Warm/cool water thermal guild supporting the Jock River fishery

Fish Community

  • Twenty-three species of recreational and bait fish

Shoreline Cover Type (30 m. riparian area; 2014)

  • Wetland (39%)
  • Crop and Pasture (29%)
  • Woodland (15%)
  • Transportation (6%)
  • Meadow-Thicket (5%)
  • Settlement (4%)
  • Aggregate (2%)

Land Cover Type (2014)

  • Crop and Pasture (31%)
  • Woodland (26%)
  • Wetland (24%)
  • Settlement (8%)
  • Meadow-Thicket (6%)
  • Transportation (3%)
  • Aggregate (2%)
  • Water (<1%)

Land Cover Change (2008 to 2014)

  • Woodland (-22 ha)
  • Aggregate (-6 ha)
  • Wetland (-3 ha)
  • Meadow-Thicket (0 ha)
  • Transportation (0 ha)
  • Water (+7 ha)
  • Settlement (+8 ha)
  • Crop and Pasture (+16 ha)

Significant Natural Features

  • Goulbourn Provincially Significant Wetland
  • Richmond Fen Provincially Significant Wetland

Water Wells

  • Several hundred (~250) operational private water wells in the Hobbs Drain Catchment. Groundwater uses are mainly domestic, but also include public water supplies, livestock watering and commercial uses


  • There are parts of 3 bedrock quarry licenses located and 2 sand and gravel pits within the catchment. Sand and gravel resources are mainly of tertiary importance

Species at Risk (Elemental Occurrence)

  • Spotted Turtle (Endangered)
  • Blanding’s Turtle, Bobolink, Eastern Meadowlark (Threatened)
  • Eastern Milksnake, Snapping Turtle, Yellow Rail (Special Concern)

1.4 Catchment Care


  • Seventeen stewardship projects undertaken (see Section 5)

Environmental Monitoring

  • Chemical surface (in-stream) water quality collection since 2003 (see Section 2)
  • Benthic invertebrate (aquatic insect) surface (in-stream) water quality collection since 2003 (see Section 3.1.1)
  • Six headwater drainage feature assessments in 2015 at road crossings in the catchment. The protocol measures zero, first and second order headwater drainage features and is a rapid assessment method characterizing the amount of water, sediment transport, and storage capacity within headwater drainage features (see Section 3.2)
  • Groundwater level and chemistry data is available from PGMN wells located along Fernbank Road (W175) and in Stapledon (W084)

Environmental Management

  • Development along the Hobbs Drain and in and adjacent to the Provincially Significant Wetlands in the catchment (Goulbourn, Richmond Fen) 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
  • Two active Permits To Take Water (PTTW) in the Hobbs Drain catchment issued for pit /quarry dewatering
  • Five Environmental Compliance Approvals and/or Environmental Activity and Sector Registrations in the Hobbs Drain Catchment. These are for a municipal or private sewage work; industrial sewage works; and a municipal drinking water system