Jock River Subwatershed Report 2016
Ashton-Dwyer Hill Catchment
The RVCA produces individual reports for 12 catchments in the Jock River subwatershed. Using data collected and analyzed by the RVCA through its watershed monitoring and land cover classification programs, surface water quality and in-stream conditions are reported for the Jock River along with a summary of environmental conditions for the surrounding countryside every six years.
This information is used to better understand the effects of human activity on our water resources, allows us to better track environmental change over time and helps focus watershed management actions where they are needed the most to help sustain the ecosystem services (cultural, aesthetic and recreational values; provisioning of food, fuel and clean water; regulation of erosion/natural hazard protection and water purification; supporting nutrient/water cycling and habitat provision) provided by the catchment’s lands and forests and waters (Millennium Ecosystem Assessment 2005).
The following sections of this report for the Ashton-Dwyer Hill catchment are a compilation of that work.
|Surface Water Quality Conditions
|Land Stewardship and Water Resources Protection
For other Jock River catchments and the Jock River Subwatershed Report, please visit the RVCA website at www.rvca.ca
Figure 1 Land cover in the Ashton-Dwyer Hill catchment
1.0 Jock River-Ashton Dwyer Hill: Catchment Facts
1.1 General/Physical Geography
- Beckwith (27 km2; 34% of catchment)
- Ottawa: (53 km2; 66% of catchment)
- The Ashton Catchment resides with an extensive physiographic region known as the Smith Falls Limestone Plain. In this catchment, the limestone plain is generally but discontinuously overlain by glacial till, organic soils, sand and localized areas of beach sands and gravels
- In this catchment, bedrock includes the interbedded limestone and dolostone, sandstone with shale and limestone, dolostone, and some limestone respectively from the Gull River, Rockcliffe, Oxford and Bobcaygeon Formations. In addition, numerous geologic faults may pass through the catchment
- The ground surface ranges in elevation from approximately 162 masl near Hwy 7 to approximately 100 masl at the catchment’s outlet
- 81 square kilometers; occupies 14 percent of the Jock River subwatershed, two percent of the Rideau Valley watershed
- Jock River and tributaries: 153 km
1.2 Vulnerable Areas
- Jock River 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 the catchment ranges from 124.9 metres above mean sea level at the upper, mapped extent of the regulation limit in Ashton Village to 101.8 metres above mean sea level at the Jock Trail
- The Mississippi-Rideau Source Protection initiative has mapped scattered parts of this catchment as a significant groundwater recharge areas and all the catchment as Highly Vulnerable Aquifer. Wellhead Protection Areas (WHPA) A and parts of WHPAs B, C and D for the municipal wells in Munster Hamlet, underlie a small part of the catchment near Bleeks Road and also Crawford Side Road
- 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 Ashton-Dwyer Hill catchment
1.3 Conditions at a Glance
- Surface chemistry water quality rating on the Jock River in the Ashton-Dwyer Hill catchment declines from “Fair” at the upstream (JR-45) site to “Poor” at the downstream site (JR-20). The scores at both sites are largely influenced by frequent high nutrient concentrations and periods of bacterial pollution (see Figure 2)
- Instream biological water quality conditions at the Jock River Ashton-Dwyer Hill sample location aquatic habitat conditions from a benthic invertebrate perspective is considered “Poor” from 2011 to 2015 as the samples are dominated by species that are moderately sensitive and tolerant to high organic pollution levels
Instream and Riparian
- Overall instream and riparian condition for the Jock River-Ashton Dwyer Hill catchment as assessed by the stream characterization and headwater drainage feature assessment programs show that the Jock River and its tributaries are in generally good condition. The majority of the system has low erosion levels and a healthy forested riparian corridor along the Jock River. Instream diversity of aquatic habitat is fairly complex in the lower to middle reaches of the Jock River, while the upper reach is dominated by low habitat complexity and poor dissolved oxygen conditions
- Warm/cool water thermal guild supporting the Jock River/Rideau River fishery
- Thirty-five species of recreational and bait fish
Shoreline Cover Type (30 m. riparian area; 2014)
- Wetland (36%)
- Crop and Pasture (28%)
- Woodland (18%)
- Settlement (8%)
- Transportation (7%)
- Meadow-Thicket (3%)
- Aggregate (<1%)
Land Cover Type (2014)
- Crop and Pasture (39%)
- Woodland (22%)
- Wetland (21%)
- Settlement (9%)
- Meadow-Thicket (4%)
- Transportation (3%)
- Aggregate (<1%)
- Water (<1%)
Land Cover Change (2008 to 2014)
- Wetland (-61 ha)
- Woodland (-34 ha)
- Meadow-Thicket (-20 ha)
- Crop and Pasture (-5 ha)
- Water (0 ha)
- Aggregate (+9 ha)
- Settlement (+55 ha)
- Transportation (+56 ha)
Significant Natural Features
- Goodwood Provincially Significant Wetland
- Goodwood Marsh Area of Natural and Scientific Interest
- Manions Corners Provincially Significant Wetland
- Prospect Bog Provincially Significant Wetland
- Several hundred (~ 630) operational private water wells in the catchment. Groundwater uses are mainly domestic but also include livestock watering, commercial uses, groundwater monitoring and testing and municipal and other public water supplies
- One sand and gravel pit within the catchment. Sand and gravel resources are limited and of tertiary importance
Species at Risk (Elemental Occurrence)
- Loggerhead Shrike, Spotted Turtle (Endangered)
- Bobolink, Eastern Meadowlark (Threatened)
- Eastern Milksnake, Snapping Turtle (Special Concern)
1.4 Catchment Care
- Eighty-three stewardship projects undertaken (see Section 5)
- Chemical surface (in-stream) water quality collection since 2003 (see Section 2)
- Benthic invertebrate (aquatic insect) surface (in-stream) water quality collection since 2011 (see Section 3.3.1)
- Fish survey along the Jock River (see Section 3.3.11)
- Stream characterization survey on the Jock River in 2015, working upstream to the headwaters from its mouth where it empties into the Rideau River, taking measurements and recording observations on instream habitat, bank stability, other attributes and preparing a temperature profile (see Section 3)
- Twenty 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 3.4)
- Development in and adjacent to the Provincially Significant Wetlands in the catchment (Goodwood Marsh, Manions Corners, Prospect Bog) 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
- Ashton Dam water levels are managed by the RVCA on behalf of the Township of Beckwith and the City of Ottawa
- Three active Permit To Take Water (PTTW) in the catchment issued for municipal water supply and golf course irrigation
- Seven Environmental Compliance Approvals in the catchment. These are for municipal or private sewage works; an industrial sewage work; a waste management system and air emissions
2.0 Jock River-Ashton Dwyer Hill Catchment: Surface Water Quality Conditions
Surface water quality conditions in the Ashton-Dwyer Hill catchment of the Jock River are monitored by the City of Ottawa’s Baseline Water Quality Monitoring Program. This program provides information on the condition of Ottawa’s surface water resources; data is collected for multiple parameters including nutrients (total phosphorus, total Kjeldahl nitrogen and ammonia), E. coli, metals (like aluminum and copper) and additional chemical/physical parameters (such as alkalinity, chlorides, pH and total suspended solids). The locations of monitoring sites are shown in Figure 2 and Table 1.
Figure 2 Water quality monitoring sites on the Jock River in the Ashton-Dwyer Hill Catchment
2.1 Jock River Water Quality Rating
The RVCA's water quality rating for Jock River site JR-20 is “Poor” while upstream site JR-45 is “Fair” (Table 1) as determined by the Canadian Council of Ministers of the Environment (CCME) Water Quality Index. A “Fair” rating indicates that water quality is usually protected but is occasionally threatened or impaired; conditions sometimes depart from natural or desirable levels. A rating of “Poor” indicates water quality is frequently threatened or impaired; conditions often depart from natural or desirable levels. Each parameter is evaluated against established guidelines to determine water quality conditions. Those parameters that frequently exceed guidelines are presented below. Table 1 shows the overall rating for the monitored surface water quality site within the Ashton-Dwyer Hill catchment and Table 2 outlines the Water Quality Index (WQI) scores and their corresponding ratings.
Analysis of the data has been broken into two periods, 2004-2009 and 2010-2015, to examine if conditions have changed within this timeframe. Water quality scores at site JR-20 declined from a rating of “Fair” in the 2004-2009 period to “Poor” in 2010-2015, this can be attributed to more exceedances across a greater number of parameters. Data is only available at site JR-45 for the 2010-2015 period. The scores at both sites are largely influenced by frequent high nutrient concentrations and periods of bacterial pollution. For more information on the CCME WQI, please see the Jock River Subwatershed Report.
Water Quality Index ratings for the Ashton-Dwyer Hill Catchment
Water Quality Index ratings and corresponding index scores (RVCA terminology, original WQI category names in brackets)
Total phosphorus (TP) is used as a primary indicator of excessive nutrient loading and may contribute to abundant aquatic vegetation growth and depleted dissolved oxygen levels. The Provincial Water Quality Objective (PWQO) is used as the TP Guideline and states that in streams concentrations greater than 0.030 mg/l indicate an excessive amount of TP.
Total Kjeldahl nitrogen (TKN) and ammonia (NH3) are used as secondary indicators of nutrient loading. RVCA uses a guideline of 0.500 mg/l to assess TKN and the PWQO of 0.020 mg/l to assess NH3 concentrations in the Jock River.
Tables 3, 4 and 5 summarize average nutrient concentrations at the monitored site within the Ashton-Dwyer Hill catchment and show the proportion of results that meet the guidelines.
Summary of total phosphorus results for the Ashton-Dwyer Hill catchment, 2004-2009 and 2010-2015. Highlighted values indicate average concentrations exceed the guideline
Summary of total Kjeldahl nitrogen results for the Ashton-Dwyer Hill catchment from 2004-2009 and 2010-2015. Highlighted values indicate average concentrations exceed the guideline
Summary of ammonia results for the Ashton-Dwyer Hill catchment from 2004-2009 and 2010-2015. Highlighted values indicate average concentrations exceed the guideline
Monitoring Site JR-20
In the 2004-2009 period the majority of samples at site JR-20 were above the TP guideline; the frequency of exceedances decreased marginally in the 2010-2015 monitoring period. The number of samples below the guideline improved from 47 percent in 2004-2009 to 56 percent in 2010-2015 (Figures 3 and 4). The average TP concentrations decreased slightly from 0.037 mg/l (2004–2009) to 0.031 mg/l (2010–2015) as shown in Table 3.
TKN concentrations show that the bulk of results exceeded the guideline (Figures 5 and 6); there were few samples (eight percent) below the guideline in the 2004-2009 period and this declined to zero samples below the guideline in the 2010-2015 period. The average concentration was generally elevated and increased from 0.867 mg/l to 0.874 mg/l (Table 4).
In the 2004-2009 reporting period 75 percent of NH3 results were below the guideline with an average concentration of 0.030 mg/l (Figure 7, Table 5). The percentage of results below the guideline declined to 70 percent in the 2010-2015 period. However, during this timeframe the average concentration also decreased marginally to 0.028 mg/l (Figure 8, Table 5).
Monitoring Site JR-45
Elevated TP results were not a common occurrence at site JR-45. Most samples, 76 percent, were below the PWQO (Figure 4). The average TP concentration was 0.023 mg/l (Table 3) and was also below the guideline (PWQO).
The bulk of TKN results have exceeded the guideline (Figure 6), with seven percent of samples below the guideline in the 2010-2015. The average concentration was elevated at 0.808 mg/l (Table 4).
The results for NH3 indicate that exceedances not common though the average concentration was above the guideline at 0.023 mg/l (Table 5). Seventy-two percent of results were below the guideline in the 2010-2015 reporting period (Figure 8).
Figure 3 Total phosphorus concentration in the Jock River, Ashton-Dwyer Hill catchment, 2004-2009
Figure 4 Total phosphorus concentration in the Jock River, Ashton-Dwyer Hill catchment, 2010-2015
Figure 5 Total Kjeldahl nitrogen concentrations in the Jock River, Ashton-Dwyer Hill catchment, 2004-2009
Figure 6 Total Kjeldahl nitrogen concentration in the Jock River, Ashton-Dwyer Hill catchment, 2010-2015
Figure 7 Ammonia concentration in the Jock River, Ashton-Dwyer Hill catchment, 2004-2009
Figure 8 Ammonia concentrations in the Jock River, Ashton-Dwyer Hill catchment, 2010-2015
Nutrient enrichment is a feature in this reach of the Jock River. This is likely due to natural inputs from wetland areas and runoff from surrounding agricultural lands. The Jock River was previously identified as having a marginal rating (i.e. exceeded targets occasionally) for phosphorus (City of Ottawa, Water Environment Protection Program, 2006). Overall, average nutrient concentrations have remained consistent through the monitoring periods at site JR-20. All parameters (total phosphorus, total Kjeldahl nitrogen and ammonia) have exceeded guidelines. Elevated nutrients may result in nutrient loading downstream. High nutrient concentrations can help stimulate the growth of algae blooms and other aquatic vegetation in a waterbody and deplete oxygen levels as the vegetation dies off. Consideration should also be given to the potential influence of inflow from the Jenkinson Drain into this reach of the Jock River. Best management practices such as enhanced shoreline buffers, erosion mitigation where applicable, preventing the use of fertilizers and restricting livestock access in agricultural areas can help to reduce nutrient enrichment in Jock River.
2.3 Escherichia coli
Escherichia coli (E. coli) is used as an indicator of bacterial pollution from human or animal waste; in elevated concentrations, it can pose a risk to human health. The PWQO of 100 colony forming units/100 millilitres (CFU/100 ml) is used. E. coli counts greater than this guideline indicate that bacterial contamination may be a problem within a waterbody.
Table 6 summarizes the geometric mean for the monitored sites on the Jock River within the Ashton-Dwyer Hill catchment and shows the proportion of samples that meet the E. coli guideline of 100 CFU/100 ml. The results of the geometric mean with respect to the guideline for the two periods, 2004-2009 and 2010-2015, are shown in Figures 9 and 10 respectively.
Summary of E. coli
results for the Jock River, 2004-2009 and 2010-2015
Monitoring Site JR-20
E. coli counts at site JR-20 provide evidence of an increase in bacterial pollution. The proportion of samples below the guideline declined marginally from 48 percent (Figure 9) to 46 percent (Figure 10). The count at the geometric mean increased from 78 CFU/100ml in 2004-2009 to 99 CFU/100ml from 2010-2015 (Table 6), and is just below the PWQO.
Monitoring Site JR-45
Elevated E. coli counts at site JR-45 were also regular occurrence. Most samples were below the guideline (57 percent) in the 2010-2015 period. The geometric mean was below the PWQO of 100 CFU/100ml at 74 CFU/100ml (Table 6).
Figure 9 Geometric mean of E. coli results in the Jock River, Ashton-Dwyer Hill catchment, 2004-2009
Figure 10 Geometric mean of E. coli results in the Jock River, Ashton-Dwyer Hill catchment, 2010-2015
Given the results, bacterial contamination appear to be an increasing concern in this reach of the Jock River. Exceedances are common and counts at the geometric mean have increased to just below the guideline at site JR-20. As privously noted the potential impact of the Jenkinson Drain on this reach of the Jock River should also be considered. Best management practices such as enhancing shoreline buffers and restricting livestock access can help to protect this reach of the Jock River into the future.
1 The City of Ottawa Baseline Water Quality Monitoring Program has also applied the CCME WQI to monitored sites. The parameters used and time periods differs between the RVCA and City of Ottawa’s application of the WQI, resulting in different ratings at some sites.
2 No Ontario guideline for TKN is presently available; however, waters not influenced by excessive organic inputs typically range from 0.100 to 0.500 mg/l, Environment Canada (1979) Water Quality Sourcebook, A Guide to Water Quality Parameters, Inland Waters Directorate, Water Quality Branch, Ottawa, Canada
3 A type of mean or average, which indicates the central tendency or typical value of a set of numbers by using the product of their values (as opposed to the arithmetic mean which uses their sum). It is often used to summarize a variable that varies over several orders of magnitude, such as E. coli counts
3.0 Jock River-Ashton Dwyer Hill Catchment: Riparian Conditions
3.1 Jock River Overbank Zone
3.1.1 Riparian Buffer Land Cover Evaluation
Figure 11 demonstrates the buffer conditions of the left and right banks separately. The Jock River in the Ashton - Dwyer Hill catchment had a buffer of greater than 30 meters along 71 percent of the right bank and 70 percent of the left bank.
Figure 11 Riparian Buffer Evaluation along the Jock River in the Ashton - Dwyer Hill catchment
3.1.2 Riparian Buffer Alterations
Alterations within the riparian buffer were assessed within three distinct shoreline zones (0-5m, 5-15m, 15-30m), and evaluated based on the dominant vegetative community and/or land cover type (Figure 12). The riparian buffer zone along the Jock River within the Ashton - Dwyer Hill catchment was found to have highly variable conditions along the riparian corridor. These alterations were generally associated with infrastructure in the form of road crossings, recreational and agricultural land uses.
Figure 12 Riparian buffer alterations within the Jock River Ashton - Dwyer Hill catchment
3.1.3 Adjacent Landuse
The RVCA’s Stream Characterization Program identifies ten different land uses beside the Jock River in the Ashton - Dwyer Hill catchment (Figure 13). Surrounding land use is considered from the beginning to end of the survey section (100m) and up to 100m on each side of the river. Land use outside of this area is not considered for the surveys but is nonetheless part of the subwatershed and will influence the creek. Natural areas made up 65 percent of the stream, characterized by forest, scrubland, meadow and wetland. Forest habitat was dominant in the adjacent lands along the Jock River in the Ashton - Dwyer Hill catchment at 35 percent. The remaining land use consisted of active agriculture, pasture, abandoned agriculture, residential, recreational and infrastructure in the form of road crossings.
Figure 13 Land Use along the Jock River in the Ashton - Dwyer Hill catchment
3.2 Jock River Shoreline Zone
3.2.1 Instream Erosion
Stream erosion is the process by which water erodes and transports sediments, resulting in dynamic flows and diverse habitat conditions. Excessive erosion can result in drastic environmental changes, as habitat conditions, water quality and aquatic life are all negatively affected. Bank stability was assessed as the overall extent of each section with “unstable” shoreline conditions. These conditions are defined by the presence of significant exposed soils/roots, minimal bank vegetation, severe undercutting, slumping or scour and potential failed erosion measures. The majority of the Jock River in the Ashton-Dwyer Hill catchment had low levels of erosion with the exception of three areas along the system which had moderate to high levels of erosion. Figure 14 shows erosion levels along the Jock River in the Ashton-Dwyer Hill catchment.
Figure 14 Erosion along the Jock River in the Ashton - Dwyer Hill catchment
3.2.2 Undercut Stream Banks
Stream bank undercuts can provide excellent cover habitat for aquatic life, however excessive levels can be an indication of unstable shoreline conditions. Bank undercut was assessed as the overall extent of each surveyed section with overhanging bank cover present. Figure 15 shows that Jock River in the Ashton - Dwyer Hill catchment had low levels of undercut banks along the majority of the system with a few specific locations having high levels of undercut banks observed.
Figure 15 Undercut stream banks along the Jock River in the Ashton - Dwyer Hill catchment
3.2.3 Stream Shading
Grasses, shrubs and trees all contribute towards shading a stream. Shade is important in moderating stream temperature, contributing to food supply and helping with nutrient reduction within a stream. Stream cover is assessed as the total coverage area in each section that is shaded by overhanging trees/grasses and tree canopy, at greater than 1m above the water surface. Figure 16 shows variable conditions of low to high levels of stream shading along the Jock River in the Ashton - Dwyer Hill catchment.
Figure 16 Stream shading along the Jock River in the Ashton - Dwyer Hill catchment
3.2.4 Instream Woody Debris
Figure 17 shows that the majority of Jock River in the Ashton - Dwyer Hill catchment had predominantly low levels of instream woody debris in the form of branches and trees along the system. Instream woody debris is important for fish and benthic invertebrate habitat, by providing refuge and feeding areas.
Figure 17 Instream woody debris along the Jock River in the Ashton - Dwyer Hill catchment
3.2.5 Overhanging Trees and Branches
Trees and branches that are less than one meter from the surface of the water are defined as overhanging. Overhanging branches and trees provide a food source, nutrients and shade which helps to moderate instream water temperatures. Figure 18 shows the system is highly variable with low to high levels of overhanging branches and trees along Jock River in the Ashton - Dwyer Hill catchment.
Figure 18 Overhanging trees and branches along the Jock River in the Ashton - Dwyer Hill catchment
3.2.6 Anthropogenic Alterations
Stream alterations are classified based on specific functional criteria associated with the flow conditions, the riparian buffer and potential human influences. Figure 19 shows 46 percent of the Jock River in the Ashton - Dwyer Hill catchment remains “unaltered” with no anthropogenic alterations. Forty nine percent of Jock River in the Ashton - Dwyer Hill catchment was classified as natural with minor anthropogenic changes while four percent was considered altered and two percent was classified as highly altered. The alterations along the Jock River in this reach were in the form of shoreline modifications, reduced buffers and road crossings.
Figure 19 Anthropogenic alterations along the Jock River in the Ashton - Dwyer Hill catchment
3.3 Jock River Instream Aquatic Habitat
3.3.1 Benthic Invertebrates
Freshwater benthic invertebrates are animals without backbones that live on the stream bottom and include crustaceans such as crayfish, molluscs and immature forms of aquatic insects. Benthos represent an extremely diverse group of aquatic animals and exhibit wide ranges of responses to stressors such as organic pollutants, sediments and toxicants, which allows scientists to use them as bioindicators. As part of the Ontario Benthic Biomonitoring Network (OBBN), the RVCA has been collecting benthic invertebrates at the Franktown Road site on the Jock River since 2011 (Site Code JO-3). Monitoring data is analyzed for each sample site and the results are presented using the Family Biotic Index, Family Richness and percent Ephemeroptera, Plecoptera and Trichoptera.
Hilsenhoff Family Biotic Index
The Hilsenhoff Family Biotic Index (FBI) is an indicator of organic and nutrient pollution and provides an estimate of water quality conditions for each site using established pollution tolerance values for benthic invertebrates. FBI results for the Jock River Ashton - Dwyer Hill catchment sample location at Franktown Road are summarized by year from 2011 to 2015. “Good” to “Poor” water quality conditions was observed at the Jock River Ashton - Dwyer Hill sample location for the period from 2011 to 2015 (Figure 20) using a grading scheme developed by Conservation Authorities in Ontario for benthic invertebrates.
Figure 20 Hilsenhoff Family Biotic Index at the Jock River Franktown Road sample location
Family Richness measures the health of the community through its diversity and increases with increasing habitat diversity suitability and healthy water quality conditions. Family Richness is equivalent to the total number of benthic invertebrate families found within a sample. The Jock River Ashton - Dwyer Hill site is reported to have “Fair” family richness (Fig.xx).
Figure 21 Family Richness at the Jock River Franktown Road sample location
Ephemeroptera (Mayflies), Plecoptera (Stoneflies), and Trichoptera (Caddisflies) are species considered to be very sensitive to poor water quality conditions. High abundance of these organisms is generally an indication of good water quality conditions at a sample location. The community structure typically has species that are more tolerant to poorer water quality conditions. As a result, the EPT indicates that the Jock River Ashton - Dwyer Hill sample location is reported to have “Fair” to “Poor” water quality (Figure 22) from 2011 to 2015.
Figure 22 EPT at the Jock River Franktown Road sample location
Overall the Jock River Ashton - Dwyer Hill sample location aquatic habitat conditions from a benthic invertebrate perspective is considered “Poor” from 2011 to 2015 as the samples are dominated by species that are moderately sensitive and tolerant to high organic pollution levels.
3.3.2 Habitat Complexity
Habitat complexity is a measure of the overall diversity of habitat types and features within a stream. Streams with high habitat complexity support a greater variety of species niches, and therefore contribute to greater diversity. Factors such as substrate, flow conditions (pools, riffles) and cover material (vegetation, wood structure, etc.) all provide crucial habitat to aquatic life. Habitat complexity is assessed based on the presence of boulder, cobble and gravel substrates, as well as the presence of instream woody material.
Low to high habitat complexity was identified for the Jock River Ashton - Dwyer Hill catchment (Figure 23). Regions with increased habitat complexity were observed in the lower to middle reaches of the system within the catchment.
Figure 23 Habitat complexity along the Jock River in the Ashton - Dwyer Hill catchment
3.3.3 Instream Substrate
Diverse substrate is important for fish and benthic invertebrate habitat because some species have specific substrate requirements and for example will only reproduce on certain types of substrate. The absence of diverse substrate types may limit the overall diversity of species within a stream. Figure 24 shows that 77 percent of the sections observed in the Jock River in the Ashton - Dwyer Hill catchment had the presence of cobble substrate. Overall substrate conditions were highly diverse along the Jock River Ashton - Dwyer Hill reach with all substrate types being recorded along the reach. Figure 25 shows the dominant substrate type observed for each section surveyed along the Jock River in the Ashton - Dwyer Hill catchment.
Figure 24 Instream substrate along the Jock River in the Ashton - Dwyer Hill catchment
Figure 25 Dominant substrate type along the Jock River Ashton - Dwyer Hill catchment
3.3.4 Instream Morphology
Pools and riffles are important habitat features for aquatic life. Riffles are fast flowing areas characterized by agitation and overturn of the water surface. Riffles thereby play a crucial role in contributing to dissolved oxygen conditions and directly support spawning for some fish species. They are also areas that support high benthic invertebrate populations which are an important food source for many aquatic species. Pools are characterized by minimal flows, with relatively deep water and winter/summer refuge habitat for aquatic species. Runs are moderately shallow, with unagitated surfaces of water and areas where the thalweg (deepest part of the channel) is in the center of the channel. Figure 26 shows that the Jock River in the Ashton - Dwyer Hill catchment is highly variable; 66 percent consists of runs, 12 percent riffles and 21 percent pools. Figure 27 shows where the riffle habitat areas were observed along the Jock River in the Ashton - Dwyer Hill catchment.
Figure 26 Instream morphology along the Jock River in the Ashton - Dwyer Hill catchment
Figure 27 Riffle habitat locations along the Jock River in the Ashton - Dwyer Hill catchment
3.3.5 Vegetation Type
Instream vegetation provides a variety of functions and is a critical component of the aquatic ecosystem. Aquatic plants promote stream health by:
- Providing direct riparian/instream habitat
- Stabilizing flows reducing shoreline erosion
- Contributing to dissolved oxygen through photosynthesis
- Maintaining temperature conditions through shading
For example emergent plants along the shoreline can provide shoreline protection from wave action and important rearing habitat for species of waterfowl. Submerged plants provide habitat for fish to find shelter from predator fish while they feed. Floating plants such as water lilies shade the water and can keep temperatures cool while reducing algae growth. Narrow leaved emergents were present at 89% of the sections surveyed, algae was observed in 74% of sections, while free floating plants were observed in 27% of surveyed sections. Broad leaved emergents were observed in 44% of sections, submerged plants in 81%, floating plants in 27% and robust emergents in 50% of sections surveyed. Figure 28 depicts the plant community structure for the Jock River Ashton - Dwyer Hill catchment. Figure xx shows the dominant vegetation type observed for each section surveyed along the Jock River in the Ashton - Dwyer Hill catchment.
Figure 28 Vegetation type along the Jock River in the Ashton - Dwyer Hill catchment
Figure 29 Dominant vegetation type along the Jock River in the Ashton - Dwyer Hill catchment
3.3.6 Instream Vegetation Abundance
Instream vegetation is an important factor for a healthy stream ecosystem. Vegetation helps to remove contaminants from the water, contributes oxygen to the stream, and provides habitat for fish and wildlife. Too much vegetation can also be detrimental. Figure 30 demonstrates that the Jock River Ashton - Dwyer Hill reach had no vegetation to low levels of instream vegetation for 53 percent of its length. Normal to common levels of vegetation were recorded at 26 percent of stream surveys. Extensive levels of vegetation were observed along 21 percent of the systems length.
Figure 30 Instream vegetation abundance along the Jock River in the Ashton - Dwyer Hill catchment
3.3.7 Invasive Species
Invasive species can have major implications on streams and species diversity. Invasive species are one of the largest threats to ecosystems throughout Ontario and can out compete native species, having negative effects on local wildlife, fish and plant populations. Ninety three percent of the sections surveyed along the Jock River Ashton - Dwyer Hill reach had invasive species. The invasive species observed in the Jock River Ashton - Dwyer Hill reach were European frogbit, poison/wild parsnip, dog strangling vine, yellow iris, purple loosestrife, rusty crayfish, glossy buckthorn, garlic mustard and Manitoba maple. Invasive species abundance (i.e. the number of observed invasive species per section) was assessed to determine the potential range/vector of many of these species (Figure 31).
Figure 31 Invasive species abundance along the Jock River in the Ashton - Dwyer Hill catchment
3.3.8 Water Chemistry
During the stream characterization survey, a YSI probe is used to collect water chemistry information. Dissolved oxygen (DO), specific conductivity (SPC) and pH are measured at the start and end of each section.
184.108.40.206 Dissolved Oxygen
Dissolved oxygen is a measure of the amount of oxygen dissolved in water. The Canadian Environmental Quality Guidelines of the Canadian Council of Ministers of the Environment (CCME) suggest that for the protection of aquatic life the lowest acceptable dissolved oxygen concentration should be 6 mg/L for warmwater biota and 9.5 mg/L for coldwater biota (CCME, 1999). Figure 32 shows that the dissolved oxygen in the Jock River Ashton - Dwyer Hill catchment was within the threshold for warmwater biota in this reach of the system. The average dissolved oxygen levels observed within the main stem of the Jock River Ashton - Dwyer Hill was 6.72mg/L which is within the recommended levels for warmwater biota. The upper sections of the reach fell below the recommended 6.0mg/L for warmwater biota.
Figure 32 Dissolved oxygen ranges in the Jock River for the Ashton - Dwyer Hill catchment
Conductivity in streams is primarily influenced by the geology of the surrounding environment, but can vary drastically as a function of surface water runoff. Currently there are no CCME guideline standards for stream conductivity; however readings which are outside the normal range observed within the system are often an indication of unmitigated discharge and/or stormwater input. The average conductivity observed within the main stem of Jock River in the Ashton - Dwyer Hill catchment was 404.36 µs/cm. Figure 33 shows the conductivity readings for the Jock River in the Ashton - Dwyer Hill catchment.
Figure 33 Specific conductivity ranges in the Jock River for the Ashton - Dwyer Hill catchment
Based on the PWQO for pH, a range of 6.5 to 8.5 should be maintained for the protection of aquatic life. Average pH values for the Jock River Ashton - Dwyer Hill catchment averaged 7.95 thereby meeting the provincial standard (Figure 34).
Figure 34 pH ranges in the Jock River for the Ashton - Dwyer Hill catchment
220.127.116.11 Oxygen Saturation (%)
Oxygen saturation is measured as the ratio of dissolved oxygen relative to the maximum amount of oxygen that will dissolve based on the temperature and atmospheric pressure. Well oxygenated water will stabilize at or above 100% saturation, however the presence of decaying matter/pollutants can drastically reduce these levels. Oxygen input through photosynthesis has the potential to increase saturation above 100% to a maximum of 500%, depending on the productivity level of the environment. In order to represent the relationship between concentration and saturation, the measured values have been summarized into 6 classes:
- <100% Saturation / <6.0 mg/L Concentration. Oxygen concentration and saturation are not sufficient to support aquatic life and may represent impairment
- >100% Saturation / <6.0 mg/L Concentration. Oxygen concentration is not sufficient to support aquatic life, however saturation levels indicate that the water has stabilized at its estimated maximum. This is indicative of higher water temperatures and stagnant flows.
- <100% Saturation / 6.0—9.5 mg/L Concentration. Oxygen concentration is sufficient to support warmwater biota, however depletion factors are likely present and are limiting maximum saturation.
- >100% Saturation / 6.0—9.5 mg/L Concentration. Oxygen concentration and saturation levels are optimal for warmwater biota.
- <100% Saturation / >9.5 mg/L Concentration. Oxygen concentration is sufficient to support coldwater biota, however depletion factors are likely present and are limiting maximum saturation.
- >100% Saturation / >9.5 mg/L Concentration. Oxygen concentration and saturation levels are optimal for coldwater biota.
Figure 35 A bivariate assessment of dissolved oxygen concentration (mg/L) and saturation (%) in the Jock River Ashton - Dwyer Hill reach
Dissolved oxygen conditions on the Jock River in the Ashton - Dwyer Hill catchment are generally sufficient for both warm and coolwater species (Figure 35). Dissolved oxygen conditions are higher in the lower reach which is a function of the riffle habitat in those sections of the Jock River. Oxygen levels in wetland habitats are typically lower than they are in areas where the substrate is dominated by cobble and riffle habitat.
18.104.22.168 Specific Conductivity Assessment
Specific conductivity (SPC) is a standardized measure of electrical conductance, collected at or corrected to a water temperature of 25⁰C. SPC is directly related to the concentration of ions in water, and is commonly influenced by the presence of dissolved salts, alkalis, chlorides, sulfides and carbonate compounds. The higher the concentration of these compounds, the higher the conductivity. Common sources of elevated conductivity include storm water, agricultural inputs and commercial/industrial effluents.
In order to summarize the conditions observed, SPC levels were evaluated as either normal, moderately elevated or highly elevated. These categories correspond directly to the degree of variation (i.e. standard deviation) at each site relative to the average across the system.
Normal levels were maintained along the majority of the Jock River in the Ashton - Dwyer Hill catchment, however there were elevated areas immediately downstream of the Riverbend golf course and in two specified locations in the middle and upper reaches within the Ashton - Dwyer Hill catchment area (Figure 36).
Figure 36 Relative specific conductivity levels on the Jock River in the Ashton - Dwyer Hill catchment
3.3.9 Thermal Regime
Many factors can influence fluctuations in stream temperature, including springs, tributaries, precipitation runoff, discharge pipes and stream shading from riparian vegetation. Water temperature is used along with the maximum air temperature (using the Stoneman and Jones method) to classify a watercourse as either warm water, cool water or cold water. Figure 37 shows where the thermal sampling sites were located along Jock River Ashton – Dwyer Hill catchment. Analysis of the data collected indicates that Jock River Ashton - Dwyer Hill catchment is classified as a warm water system with cool to warm water reaches (Figure 38).
Figure 37 Temperature logger locations in the Jock River Ashton – Dwyer Hill catchment
Figure 38 Temperature logger data for the three sites in the Jock River Ashton – Dwyer Hill catchment
Each point on the graph represents a temperature that meets the following criteria:
- Sampling dates between July 1st and September 7th
- Sampling date is preceded by two consecutive days above 24.5 °C, with no rain
- Water temperatures are collected at 4pm
- Air temperature is recorded as the max temperature for that day
Groundwater discharge areas can influence stream temperature, contribute nutrients, and provide important stream habitat for fish and other biota. During stream surveys, indicators of groundwater discharge are noted when observed. Indicators include: springs/seeps, watercress, iron staining, significant temperature change and rainbow mineral film. Figure 39 shows areas where one or more of the above groundwater indicators were observed during stream surveys and headwater assessments.
Figure 39 Groundwater indicators observed in the Jock River Ashton - Dwyer Hill catchment
3.3.11 Fish Community
The Jock River Ashton - Dwyer Hill catchment is classified as a mixed community of warm and cool water recreational and baitfish fishery with 35 species observed. Figure 40 shows the sampling locations along the Jock River in the Barrhaven catchment.
Figure 40 Fish species observed in the Jock River Ashton - Dwyer Hill catchment
Electrofishing sampling location at Franktown Road
Rainbow darter (Etheostoma caeruleum) captured at Franktown Road
The following table contains a list of species observed in the watershed.
Fish Community species found within the Jock River Ashton - Dwyer Hill catchment
3.3.12 Migratory Obstructions
It is important to know locations of migratory obstructions because these can prevent fish from accessing important spawning and rearing habitat. Migratory obstructions can be natural or manmade, and they can be permanent or seasonal. Figure 41 shows that Jock River in the Ashton - Dwyer Hill catchment had two weir barriers at the time of the survey in 2015. The Ashton Station Dam along with several natural grade barriers were observed, one debris dam and three beaver dams were identified along the Jock River in the Ashton - Dwyer Hill catchment.
Figure 41 Migratory obstructions along Jock River in the Ashton – Dwyer Hill catchment
3.3.13 Riparian Restoration
Figure 42 depicts the locations of riparian restoration opportunities as a result of observations made during the stream survey.
Figure 42 Riparian restoration opportunities along Jock River in the Ashton - Dwyer Hill catchment
3.3.14 Instream Restoration
Figure 43 depicts the locations of instream restoration opportunities as a result of observations made during the stream survey. Only one small stream garbage cleanup restoration opportunity was observed in the Ashton - Dwyer Hill catchment.
Figure 43 Instream restoration opportunities along Jock River in the Ashton - Dwyer Hill catchment
3.4 Headwater Drainage Features Assessment
3.4.1 Headwater Sampling Locations
The RVCA Stream Characterization program assessed Headwater Drainage Features for the Jock River subwatershed in 2015. This protocol measures zero, first and second order headwater drainage features (HDF). It is a rapid assessment method characterizing the amount of water, sediment transport, and storage capacity within headwater drainage features (HDF). RVCA is working with other Conservation Authorities and the Ministry of Natural Resources and Forestry to implement the protocol with the goal of providing standard datasets to support science development and monitoring of headwater drainage features. An HDF is a depression in the land that conveys surface flow. Additionally, this module provides a means of characterizing the connectivity, form and unique features associated with each HDF (OSAP Protocol, 2013). In 2015 the program sampled 20 sites at road crossings in the Jock River Ashton - Dwyer Hill catchment area (Figure 44).
Figure 44 Location of the headwater sampling site in the Jock River Ashton - Dwyer Hill catchment
3.4.2 Headwater Feature Type
The headwater sampling protocol assesses the feature type in order to understand the function of each feature. The evaluation includes the following classifications: defined natural channel, channelized or constrained, multi-thread, no defined feature, tiled, wetland, swale, roadside ditch and pond outlet. By assessing the values associated with the headwater drainage features in the catchment area we can understand the ecosystem services that they provide to the watershed in the form of hydrology, sediment transport, and aquatic and terrestrial functions. The headwater drainage features in the Ashton - Dwyer Hill catchment are primarily classified as wetland with seven, five features classified as natural, four features classified as a road side ditch, two multi thread and two features as channelized. Figure 45 shows the feature type of the primary feature at the sampling locations.
Figure 45 Headwater feature types in the Jock River Ashton - Dwyer Hill catchment
A spring photo of the headwater sample site in the Jock River Ashton - Dwyer Hill catchment located on Highway 7
A summer photo of the headwater sample site in the Jock River Ashton - Dwyer Hill catchment located on Highway 7
3.4.3 Headwater Feature Flow
The observed flow condition within headwater drainage features can be highly variable depending on timing relative to the spring freshet, recent rainfall, soil moisture, etc. Flow conditions are assessed in the spring and in the summer to determine if features are perennial and flow year round, if they are intermittent and dry up during the summer months or if they are ephemeral systems that do not flow regularly and generally respond to specific rainstorm events or snowmelt. Flow conditions in headwater systems can change from year to year depending on local precipitation patterns. Figure 46 shows the observed flow condition at the sampling locations in the Jock River Ashton - Dwyer Hill catchment in 2015.
Figure 46 Headwater feature flow conditions in the Jock River Ashton - Dwyer Hill catchment
3.4.4 Headwater Feature Channel Modifications
Channel modifications were assessed at each headwater drainage feature sampling location. Modifications include channelization, dredging, hardening and realignments. The Jock River Ashton - Dwyer Hill catchment area had five site as having been recently dredged, four locations had mixed modifications, one had channel had been hardened and ten had no channel modifications observed. Figure 47 shows the channel modifications observed at the sampling locations for Jock River Ashton - Dwyer Hill.
Figure 47 Headwater feature channel modifications in the Jock River Ashton - Dwyer Hill catchment
3.4.5 Headwater Feature Vegetation
Headwater feature vegetation evaluates the type of vegetation that is found within the drainage feature. The type of vegetated within the channel influences the aquatic and terrestrial ecosystem values that the feature provides. For some types of headwater features the vegetation within the feature plays a very important role in flow and sediment movement and provides wildlife habitat. The following classifications are evaluated no vegetation, lawn, wetland, meadow, scrubland and forest. Figure 48 depicts the dominant vegetation observed at the sampled headwater sites in the Jock River Ashton - Dwyer Hill catchment.
Figure 48 Headwater feature vegetation types in the Jock River Ashton - Dwyer Hill catchment
3.4.6 Headwater Feature Riparian Vegetation
Headwater riparian vegetation evaluates the type of vegetation that is found along the adjacent lands of a headwater drainage feature. The type of vegetation within the riparian corridor influences the aquatic and terrestrial ecosystem values that the feature provides to the watershed. Figure 49 depicts the type of riparian vegetation observed at the sampled headwater sites in the Jock River Ashton - Dwyer Hill catchment.
Figure 49 Headwater feature riparian vegetation types in the Jock River Ashton - Dwyer Hill catchment
3.4.7 Headwater Feature Sediment Deposition
Assessing the amount of recent sediment deposited in a channel provides an index of the degree to which the feature could be transporting sediment to downstream reaches (OSAP, 2013). Evidence of excessive sediment deposition might indicate the requirement to follow up with more detailed targeted assessments upstream of the site location to identify potential best management practices to be implemented. Sediment deposition ranged from none to extensive for the headwater sites sampled in the Jock River Ashton - Dwyer Hill catchment area. Figure 50 depicts the degree of sediment deposition observed at the sampled headwater sites in the Jock River Ashton - Dwyer Hill catchment.
Figure 50 Headwater feature sediment deposition in the Jock River Ashton - Dwyer Hill catchment
3.4.8 Headwater Feature Upstream Roughness
Feature roughness will provide a measure of the amount of materials within the bankfull channel that could slow down the velocity of water flowing within the headwater feature (OSAP, 2013). Materials on the channel bottom that provide roughness include vegetation, woody debris and boulders/cobble substrates. Roughness can provide benefits in mitigating downstream erosion on the headwater drainage feature and the receiving watercourse by reducing velocities. Roughness also provides important habitat conditions for aquatic organisms. Figure 51shows the feature roughness conditions at the sampling location in the Jock River Ashton - Dwyer Hill catchment.
Figure 51 Headwater feature roughness in the Jock River Ashton - Dwyer Hill catchment
4.0 Jock River-Ashton Dwyer Hill Catchment: Land Cover
Land cover and any change in coverage that has occurred over a six year period is summarized for the Ashton-Dwyer Hill catchment using spatially continuous vector data representing the catchment during the spring of 2008 and 2014. This dataset was developed by the RVCA through heads-up digitization of 20cm DRAPE ortho-imagery at a 1:4000 scale and details the surrounding landscape using 10 land cover classes.
4.1 Ashton-Dwyer Hill Catchment Land Cover Change
As shown in Table 8 and Figure 1, the dominant land cover type in 2014 was crop and pastureland followed by woodland and wetland.
Land cover (2008 vs. 2014) in the Ashton-Dwyer Hill catchment
* Does not include treed swamps ** Includes treed swamps
From 2008 to 2014, there was an overall change of 199 hectares (from one land cover class to another). Most of the change in the Ashton-Dwyer Hill catchment is a result of the conversion of crop and pastureland and wetland to settlement, wetland and settlement to transportation along with the conversion of woodland to crop and pastureland (Figure 52).
Figure 52 Land cover change in the Ashton-Dwyer Hill catchment (2014)
Table 9 provides a detailed breakdown of all land cover change that has taken place in the Ashton-Dwyer Hill catchment between 2008 and 2014.
Land cover change in the Ashton-Dwyer Hill catchment (2008 to 2014)
4.2 Woodland Cover
In the Environment Canada Guideline (Third Edition) entitled “How Much Habitat Is Enough?” (hereafter referred to as the “Guideline”) the opening narrative under the Forest Habitat Guidelines section states that prior to European settlement, forest was the predominant habitat in the Mixedwood Plains ecozone. The remnants of this once vast forest now exist in a fragmented state in many areas (including the Rideau Valley watershed) with woodland patches of various sizes distributed across the settled landscape along with higher levels of forest cover associated with features such as the Frontenac Axis (within the on-Shield areas of the Rideau Lakes and Tay River subwatersheds). The forest legacy, in terms of the many types of wildlife species found, overall species richness, ecological functions provided and ecosystem complexity is still evident in the patches and regional forest matrices (found in the Jock River subwatershed and elsewhere in the Rideau Valley watershed). These ecological features are in addition to other influences which forests have on water quality and stream hydrology including reducing soil erosion, producing oxygen, storing carbon along with many other ecological services that are essential not only for wildlife but for human well-being.
The Guideline also notes that forests provide a great many habitat niches that are in turn occupied by a great diversity of plant and animal species. They provide food, water and shelter for these species - whether they are breeding and resident locally or using forest cover to help them move across the landscape. This diversity of species includes many that are considered to be species at risk. Furthermore, from a wildlife perspective, there is increasing evidence that the total forest cover in a given area is a major predictor of the persistence and size of bird populations, and it is possible or perhaps likely that this pattern extends to other flora and fauna groups. The overall effect of a decrease in forest cover on birds in fragmented landscapes is that certain species disappear and many of the remaining ones become rare, or fail to reproduce, while species adapted to more open and successional habitats, as well as those that are more tolerant to human-induced disturbances in general, are able to persist and in some cases thrive. Species with specialized-habitat requirements are most likely to be adversely affected. The overall pattern of distribution of forest cover, the shape, area and juxtaposition of remaining forest patches and the quality of forest cover also play major roles in determining how valuable forests will be to wildlife and people alike.
The current science generally supports minimum forest habitat requirements between 30 and 50 percent, with some limited evidence that the upper limit may be even higher, depending on the organism/species phenomenon under investigation or land-use/resource management planning regime being considered/used.
As shown in Figure 53, 25 percent of the Ashton-Dwyer Hill catchment contains 1795 hectares of upland forest and 224 hectares of lowland forest (treed swamps) versus the 26 percent of woodland cover in the Jock River subwatershed. This is less than the 30 percent of forest cover that is identified as the minimum threshold required to sustain forest birds according to the Guideline and which may only support less than one half of potential species richness and marginally healthy aquatic systems. When forest cover drops below 30 percent, forest birds tend to disappear as breeders across the landscape.
Figure 53 Woodland cover and forest interior (2014)
4.2.1 Woodland (Patch) Size
According to the Ministry of Natural Resources’ Natural Heritage Reference Manual (Second Edition), larger woodlands are more likely to contain a greater diversity of plant and animal species and communities than smaller woodlands and have a greater relative importance for mobile animal species such as forest birds.
Bigger forests often provide a different type of habitat. Many forest birds breed far more successfully in larger forests than they do in smaller woodlots and some rely heavily on forest interior conditions. Populations are often healthier in regions with more forest cover and where forest fragments are grouped closely together or connected by corridors of natural habitat. Small forests support small numbers of wildlife. Some species are “area-sensitive” and tend not to inhabit small woodlands, regardless of forest interior conditions. Fragmented habitat also isolates local populations, especially small mammals, amphibians and reptiles with limited mobility. This reduces the healthy mixing of genetic traits that helps populations survive over the long run (Conserving the Forest Interior. Ontario Extension Notes, 2000).
The Environment Canada Guideline also notes that for forest plants that do not disperse broadly or quickly, preservation of some relatively undisturbed large forest patches is needed to sustain them because of their restricted dispersal abilities and specialized habitat requirements and to ensure continued seed or propagation sources for restored or regenerating areas nearby.
The Natural Heritage Reference Manual continues by stating that a larger size also allows woodlands to support more resilient nutrient cycles and food webs and to be big enough to permit different and important successional stages to co-exist. Small, isolated woodlands are more susceptible to the effects of blowdown, drought, disease, insect infestations, and invasions by predators and non-indigenous plants. It is also known that the viability of woodland wildlife depends not only on the characteristics of the woodland in which they reside, but also on the characteristics of the surrounding landscape where the woodland is situated. Additionally, the percentage of forest cover in the surrounding landscape, the presence of ecological barriers such as roads, the ability of various species to cross the matrix surrounding the woodland and the proximity of adjacent habitats interact with woodland size in influencing the species assemblage within a woodland.
In the Ashton-Dwyer Hill catchment (in 2014), 191 (54 percent) of the 356 woodland patches are very small, being less than one hectare in size. Another 137 (38 percent) of the woodland patches ranging from one to less than 20 hectares in size tend to be dominated by edge-tolerant bird species. The remaining 28 (8 percent of) woodland patches range between 21 and 181 hectares in size. Twenty-seven of these patches contain woodland between 20 and 100 hectares and may support a few area-sensitive species and some edge intolerant species, but will be dominated by edge tolerant species. Conversely, one (less than one percent) of the 356 woodland patches in the drainage area exceeds the 100 plus hectare size needed to support most forest dependent, area sensitive birds and are large enough to support approximately 60 percent of edge-intolerant species. No patch tops 200 hectares, which according to the Environment Canada Guideline will support 80 percent of edge-intolerant forest bird species (including most area sensitive species) that prefer interior forest habitat conditions.
Table 10 presents a comparison of woodland patch size in 2008 and 2014 along with any changes that have occurred over that time. A decrease (of 35 ha) has been observed in the overall woodland patch area between the two reporting periods with most change occurring in the 20 to 50 and 50 to 100 hectare woodland patch size class ranges.
Woodland patches in the Ashton-Dwyer Hill catchment (2008 and 2014)
*Includes treed swamps
4.2.2 Woodland (Forest) Interior Habitat
The forest interior is habitat deep within woodlands. It is a sheltered, secluded environment away from the influence of forest edges and open habitats. Some people call it the “core” or the “heart” of a woodland. The presence of forest interior is a good sign of woodland health, and is directly related to the woodland’s size and shape. Large woodlands with round or square outlines have the greatest amount of forest interior. Small, narrow woodlands may have no forest interior conditions at all. Forest interior habitat is a remnant natural environment, reminiscent of the extensive, continuous forests of the past. This increasingly rare forest habitat is now a refuge for certain forest-dependent wildlife; they simply must have it to survive and thrive in a fragmented forest landscape (Conserving the Forest Interior. Ontario Extension Notes, 2000).
The Natural Heritage Reference Manual states that woodland interior habitat is usually defined as habitat more than 100 metres from the edge of the woodland and provides for relative seclusion from outside influences along with a moister, more sheltered and productive forest habitat for certain area sensitive species. Woodlands with interior habitat have centres that are more clearly buffered against the edge effects of agricultural activities or more harmful urban activities than those without.
In the Ashton-Dwyer Hill catchment (in 2014), the 356 woodland patches contain 76 forest interior patches (Figure 53) that occupy two percent (135 ha.) of the catchment land area (which is less than the five percent of interior forest in the Jock River Subwatershed). This is below the ten percent figure referred to in the Environment Canada Guideline that is considered to be the minimum threshold for supporting edge intolerant bird species and other forest dwelling species in the landscape.
Most patches (74) have less than 10 hectares of interior forest, 54 of which have small areas of interior forest habitat less than one hectare in size. Between 2008 and 2014, there has been a large change in the number of woodland patches containing interior habitat with an overall loss of six hectares in the catchment (Table 11), suggesting an increase in forest fragmentation over the six year period.
Woodland Interior in the Ashton-Dwyer Hill catchment (2008 and 2014)
4.3 Wetland Cover
Wetlands are habitats forming the interface between aquatic and terrestrial systems. They are among the most productive and biologically diverse habitats on the planet. By the 1980s, according to the Natural Heritage Reference Manual, 68 percent of the original wetlands south of the Precambrian Shield in Ontario had been lost through encroachment, land clearance, drainage and filling.
Wetlands perform a number of important ecological and hydrological functions and provide an array of social and economic benefits that society values. Maintaining wetland cover in a watershed provides many ecological, economic, hydrological and social benefits that are listed in the Reference Manual and which may include:
- contributing to the stabilization of shorelines and to the reduction of erosion damage through the mitigation of water flow and soil binding by plant roots
- mitigating surface water flow by storing water during periods of peak flow (such as spring snowmelt and heavy rainfall events) and releasing water during periods of low flow (this mitigation of water flow also contributes to a reduction of flood damage)
- contributing to an improved water quality through the trapping of sediments, the removal and/or retention of excess nutrients, the immobilization and/or degradation of contaminants and the removal of bacteria
- providing renewable harvesting of timber, fuel wood, fish, wildlife and wild rice
- contributing to a stable, long-term water supply in areas of groundwater recharge and discharge
- providing a high diversity of habitats that support a wide variety of plants and animals
- acting as “carbon sinks” making a significant contribution to carbon storage
- providing opportunities for recreation, education, research and tourism
Historically, the overall wetland coverage within the Great Lakes basin exceeded 10 percent, but there was significant variability among watersheds and jurisdictions, as stated in the Environment Canada Guideline. In the Rideau Valley Watershed, it has been estimated that pre-settlement wetland cover averaged 35 percent using information provided by Ducks Unlimited Canada (2010) versus the 21 percent of wetland cover existing in 2014 derived from DRAPE imagery analysis.
Using the same dataset, it is estimated that pre-settlement (historic) wetland cover averaged 51 percent in the Jock River subwatershed versus the 24 percent of cover existing in 2014 (as summarized in Table 12).
Wetland cover in the Jock River subwatershed and Ashton-Dwyer Hill catchment (Historic to 2014)
This decline in wetland cover is also evident in the Ashton-Dwyer Hill catchment (as seen in Figure 54) where wetland was reported to cover 47 percent of the area prior to settlement, as compared to 21 percent in 2014. This represents a 55 percent loss of historic wetland cover. To maintain critical hydrological, ecological functions along with related recreational and economic benefits provided by these wetland habitats in the catchment, a “no net loss” of currently existing wetlands should be employed to ensure the continued provision of tangible benefits accruing from them to landowners and surrounding communities.
Figure 54 Ashton-Dwyer Hill catchment wetland cover
4.4 Shoreline Cover
The riparian or shoreline zone is that special area where the land meets the water. Well-vegetated shorelines are critically important in protecting water quality and creating healthy aquatic habitats, lakes and rivers. Natural shorelines intercept sediments and contaminants that could impact water quality conditions and harm fish habitat in streams. Well established buffers protect the banks against erosion, improve habitat for fish by shading and cooling the water and provide protection for birds and other wildlife that feed and rear young near water. A recommended target (from the Environment Canada Guideline) is to maintain a minimum 30 metre wide vegetated buffer along at least 75 percent of the length of both sides of rivers, creeks and streams.
Figure 55 shows the extent of the ‘Natural’ vegetated riparian zone (predominantly wetland/woodland features) and ‘Other’ anthropogenic cover (crop/pastureland, roads/railways, settlements) along a 30-metre-wide area of land, both sides of the shoreline of the Jock River and its tributaries in the Ashton-Dwyer Hill catchment.
Figure 55 Natural and other riparian land cover in the Ashton-Dwyer Hill catchment
This analysis shows that the riparian zone in the Ashton-Dwyer Hill catchment in 2014 was comprised of wetland (36 percent), crop and pastureland (28 percent), woodland (18 percent), settlement (eight percent), transportation (seven percent), meadow-thicket (three percent) and aggregates (less than one percent). Additional statistics for the Ashton-Dwyer Hill catchment are presented in Table 13. Of particular interest is the observed increase in the area of “Transportation” and "Meadow-Thicket" and decrease in "Woodland", "Wetland" and "Crop and Pastureland" along the shoreline of the Jock River and tributaries over a six year period.
Riparian land cover (2008 vs. 2014) in the Ashton-Dwyer Hill catchment
5.0 Jock River-Ashton Dwyer Hill Catchment: Stewardship and Water Resources Protection
The RVCA and its partners are working to protect and enhance environmental conditions in the Jock River Subwatershed. Figure 56 shows the location of all stewardship projects completed in the Jock River-Ashton Dwyer Hill catchment along with sites identified for potential shoreline restoration.
5.1 Rural Clean Water Projects
From 2010 to 2015, three precision farming and two manure storage/wastewater runoff projects were completed along with one well upgrade, one milkhouse wastewater treatment facility, one windbreak planting and one fragile land retirement. Between 2004 and 2009, two livestock fencing and two crop residue projects were finished along with two septic system replacements, one well decommissioning, one well upgrade and one nutrient management plan. Prior to 2004, four crop residue and three livestock fencing projects, three precision farming, two milkhouse wastewater treatment facilities, one septic system replacement and one manure storage/wastewater runoff project were completed. Total value of all 32 projects is $506,613 with $91,900 of that amount funded through grant dollars from the RVCA.
Figure 56 Stewardship site locations
5.2 Private Land Forestry Projects
The location of RVCA tree planting projects is shown in Figure 56. From 2010 to 2015, 24,450 trees were planted at six sites. Between 2004 and 2009, 23,057 trees were planted at 10 sites and prior to 2004, 200,460 trees were planted at 31 sites, In total, 245,967 trees were planted resulting in the reforestation of 123 hectares. Three of these projects were completed within the 30 metre riparian zone of the Jock River and its tributaries. Total project value of all 47 projects is $695,523 with $262,014 of that amount coming from fundraising sources.
Through the RVCA Butternut Recovery Program, an additional 70 butternut trees were planted in the Jock River-Ashton Dwyer Hill catchment (Figure 56) between 2004 and 2015, as part of efforts to introduce healthy seedlings from tolerant butternuts into various locations across Eastern Ontario.
5.3 Shoreline Naturalization Projects
With the assistance of the RVCA’s Shoreline Naturalization Program, 190 trees and shrubs were planted at a total project value of $1,582.
5.4 Ontario Drinking Water Stewardship Projects
Figure 56 shows the location of all Ontario Drinking Water Stewardship Program (ODWSP) projects in the Jock River-Ashton Dwyer Hill catchment. Between 2010 and 2015, two fuel handling and storage facilities and one septic system repair/replacement were completed. Total project value is $28,810 with $9,291 of that amount funded by the Ontario Ministry of the Environment.
5.5 Valley, Stream, Wetland and Hazard Lands
The Ashton-Dwyer Hill catchment covers 81 square kilometres with 17.3 square kilometres (or 21 percent) of the drainage area being within the regulation limit of Ontario Regulation 174/06 (Figure 57), giving protection to wetland areas and river or stream valleys that are affected by flooding and erosion hazards.
Wetlands occupy 17.1 sq. km. (or 21 percent) of the catchment. Of these wetlands, 8.3 sq. km (or 49 percent) are designated as provincially significant and included within the RVCA regulation limit. This leaves the remaining 8.8 sq. km (or 51 percent) of wetlands in the catchment outside the regulated area limit.
Of the 153.3 kilometres of stream in the catchment, regulation limit mapping has been plotted along 56.9 kilometers of streams (representing 37 percent of all streams in the catchment). Some of these regulated watercourses (30.1 km or 20 percent of all streams) flow through regulated wetlands; the remaining 26.8 km (or 47 percent) of regulated streams are located outside of those wetlands. Plotting of the regulation limit on the remaining 96.4 km (or 63 percent) of streams requires identification of flood and erosion hazards and valley systems.
Within those areas of the Ashton-Dwyer Hill catchment subject to the regulation (limit), efforts (have been made and) continue through RVCA planning and regulations input and review to manage the impact of development (and other land management practices) in areas where “natural hazards” are associated with rivers, streams, valley lands and wetlands. For areas beyond the regulation limit, protection of the catchment’s watercourses is only provided through the “alteration to waterways” provision of the regulation.
Figure 57 RVCA regulation limits
5.6 Vulnerable Drinking Water Areas
A portion of the Wellhead Protection Area around the Munster municipal drinking water source is located within the Jock River-Ashton Dwyer Hill drainage catchment. This area is subject to mandatory policies in the Mississippi-Rideau Source Protection Plan developed under the Clean Water Act. These policies specifically regulate land uses and activities that are considered drinking water threats, thereby reducing the risk of contamination of the municipal drinking water source.
The Jock River-Ashton Dwyer Hill drainage catchment is also considered to have a Highly Vulnerable Aquifer. This means that the nature of the overburden (thin soils, fractured bedrock) does not provide a high level of protection for the underlying groundwater making the aquifer more vulnerable to contaminants released on the surface. The Mississippi-Rideau Source Protection Plan includes policies that focus on the protection of groundwater region-wide due to the fact that most of the region, which encompasses the Mississippi and Rideau watersheds, is considered Highly Vulnerable Aquifer.
For detailed maps and policies that have been developed to protect drinking water sources, please go to the Mississippi-Rideau Source Protection Region website at www.mrsourcewater.ca to view the Mississippi-Rideau Source Protection Plan.
6.0 Jock River-Ashton Dwyer Hill Catchment: Challenges/Issues
Surface chemistry water quality on the Jock River in the catchment declines from “Fair” to “Poor” between the upstream (JR-45) and downstream sites (JR-20). The scores at both sites are largely influenced by frequent high nutrient concentrations and periods of bacterial pollution
Instream biological water quality conditions at the Jock River Ashton-Dwyer Hill sample location aquatic habitat conditions from a benthic invertebrate perspective is considered “Poor” from 2011 to 2015 as the samples are dominated by species that are moderately sensitive and tolerant to high organic pollution levels
Existing hydrological and geochemical datasets and assessments (academic, RVCA, others) are only recently available and/or are not being considered in the characterization of the numerous hydrologic functions of the Jock River subwatershed. Further, there is a dearth of hydrologic information (hydroperiod, groundwater/surface water interactions, geochemistry) about the wetlands that remain in the Jock River subwatershed
‘Natural’ vegetation covers 57 percent of the riparian zone of the Jock River and its tributaries (Figure 55) and is below the recommended 30 metre wide, naturally vegetated target along 75 percent of the length of the catchment’s watercourses
Woodlands cover 25 percent of the catchment and is less than the 30 percent of forest cover that is identified as the minimum threshold for sustaining forest birds and other woodland dependent species (Figure 53)
Pre-settlement wetlands have declined by 55 percent and now cover 21 percent (1713 ha.) of the catchment (Figure 54). Fifty-two percent (896 ha.) of these wetlands remain unevaluated/unregulated and are vulnerable to drainage and land clearing activities in the absence of any regulatory and planning controls that would otherwise protect them for the many important hydrological, social, biological and ecological functions/services/values they provide to landowners and the surrounding community
7.0 Jock River-Ashton Dwyer Hill Catchment: Opportunities/Actions
Investigate the impact of inflow from the Jenkinson drain to water quality conditions on the Jock River at site (JR-20)
Focus water quality improvements at elevated nutrient and E. coli counts via non-point and point source pollution control using best management practices such as shoreline zone enhancement and protection of natural cover
Landowners should consider taking advantage of the Rural Clean Water Programs which offer grants to landowners interested in implementing projects on their property that will help to protect and improve water quality:
- Homeowners may be interested in projects to repair, replace or upgrade their well or septic system, or addressing erosion through buffer plantings and erosion control
- Farmers can take advantage of a wide range of projects, including livestock fencing, manure storage, tile drainage control structures, cover crops, and many more
Continue to coordinate environmental monitoring and reporting activities with the City of Ottawa
Use wetland restoration as a tool to improve surface water quality and help restore the hydrologic integrity of the Jock River and its tributaries
List, share and when possible, synthesize and use existing hydrological and geochemical datasets and assessment outcomes to facilitate the characterization of subwatershed and catchment hydrological functions. In addition, prepare guidance on best practices for the preparation of water budget assessments to better understand the hydrologic cycle requirements that occur at site specific scales; and share existing catchment and subwatershed scale water budget assessment outcomes
Promote the Rideau Valley Shoreline Naturalization Program to landowners to increase existing 57 percent of natural shoreline cover
Educate landowners about the value of and best management practices used to maintain and enhance natural shorelines and headwater drainage features
Work with the Township of Beckwith and City of Ottawa to consistently implement current land use planning and development policies for water quality and shoreline protection (i.e., adherence to a minimum 30 metre development setback from water) adjacent to the Jock River and other catchment streams
Target shoreline restoration at sites identified in this report (shown as “Other riparian land cover” in Figure 55 and “Potential Riparian/Instream Restoration” in Figures 42/43) and explore other restoration and enhancement opportunities along the Jock River and its tributaries
Promote the City of Ottawa Green Acres Reforestation Program and the Rideau Valley Trees for Tomorrow Program to landowners to increase existing 25 percent of woodland cover
Encourage the Township of Beckwith and City of Ottawa to strengthen natural heritage policies in official plans and zoning by-laws where shoreline, wetland, woodland cover and watercourse setbacks are determined to be at or below critical ecological thresholds. Information for this purpose is provided in the RVCA’s subwatershed and catchment reports
Explore ways and means to more effectively enforce and implement conditions of land-use planning and development approvals to achieve net environmental gains
Re-consider the RVCA’s approach to wetland regulation where there is an identified hydrologic imperative to do so (i.e., significant loss of historic wetland cover (see Figure 54) and/or seasonal, critically low baseflows in the Jock River and/or areas of seasonal flooding)
Full Catchment Report