Grants Creek

1.1 General/Physical Geography

Drainage Area

31.1 square kilometres; occupies 3.9 percent of the Tay River subwatershed; 0.7 percent of the Rideau Valley watershed.

Geology/Physiography

The Grants Creek catchment resides within part of the physiographic region known as the Algonquin Highlands. In the Tay River Subwatershed, this ancient and hilly geologic region is made up of such Precambrian rocks as marble, conglomerates, and dark or colour banded granite-like rocks. A large area of younger sandstone is found within the centre of the catchment. Although a veneer of glacial drift (glacial till, sand etc.) overlies most of the bedrock in this catchment, large expanses of glacial till and clay overlie the central part of the catchment. A geologic fault may cut across the northern part of this catchment.

Municipal Coverage

Drummond/North Elmsley Township (1.5 km²; 5.0% of catchment)

Tay Valley Township (28.2 km²; 90.9% of catchment)

Town of Perth (1.2 km²; 4.1% of catchment)

Stream Length

All watercourses (including headwater streams): 63.2 km.

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 Grants Creek catchment.

1.3 Conditions at a Glance

Fish Community/Thermal Regime

Warm and cool water recreational and baitfish fishery with 28 species observed in Grants Creek during 2016.

Headwater Drainage Features

Classified as wetland and channelized features with historical modifications in the form of straightening.  

Instream/Riparian Habitat

Grants Creek: Low to high habitat complexity. Areas with increased habitat complexity are observed in the lower and upper reaches of the system within the catchment. The habitat complexity is considered low within the Provincially Significant Wetland along Grants Creek as defined by the criteria above; however, the wetland habitat provides the critical benefits of flood storage, water quality treatment, increased biodiversity and important aquatic and terrestrial habitat.

Catchment	Crop-Pasture	Woodland	Wetland	Meadow-Thicket	Transportation	Settlement
Hectares	-23	-9	-1	+1	+2	+32

Catchment	Crop-Pasture	Woodland	Wetland	Settlement	Meadow-Thicket	Transportation	Water
Percent	44	28	15	8	2	2	1

Catchment	Percent	Grants Creek	Percent	Streams*	Percent
Wetland	34	Wetland	56	Crop-Pasture	40
Crop-Pasture	32	Woodland	27	Wetland	27
Woodland	25	Crop-Pasture	8	Woodland	26
Settlement	5	Settlement	6	Settlement	4
Transportation	2	Transportation	1	Transportation	2
Meadow-Thicket	1	Meadow-Thicket	1	Meadow-Thicket	1

Significant Natural Features

Grants Creek Provincially Significant Wetland

Status	Species at Risk
Threatened	Blanding's Turtle	Eastern Meadowlark
Special Concern	Eastern Musk Turtle	---

Water Quality for the Protection of Aquatic Life

Water Quality Source	Grants Creek
Surface Chemistry	Poor to Very Good
Instream Biological	Poor to Fair

 

Grants Creek: Benthic invertebrate samples are highly variable with species that are sensitive and moderately tolerant to high organic pollution levels.

Water Wells

Approximately 220 operational private water wells in the Grants Creek catchment. Groundwater uses are mainly domestic, but also include livestock, industrial and commercial water supplies.

Wetland Cover

Wetlands are reported to have covered 34 percent of the Grants Creek catchment prior to European settlement, as compared to 16 percent (or 4.9 square kilometres) of the area in 2014. This represents a 54 percent (or 5.7 square kilometre) loss of historic wetland cover. Sixty-six percent of the remaining wetlands are regulated leaving 34 percent (or 1.6 square kilometers) unregulated. 

1.4 Catchment Care

Environmental Management

Development along Grants Creek (Glen Tay Road to the Tay River in the Town of Perth) and in, and adjacent to, the Grants Creek Provincially Significant Wetland in the catchment is subject to Ontario Regulation 174-06 (entitled “Development, Interference with Wetlands and Alterations to Shorelines and Watercourses”) that protects landowners and their property from natural hazards (i.e., flooding, fluctuating water table, unstable soils) along with the hydrologic function of the wetland.

Two Environmental Activity and Sector Registries were sought for a vehicle disposal facility and for an industrial heating system in the catchment.

Three Permits To Take Water (PTTW) are active in the catchment for recreation and golf course water supplies.

Environmental Monitoring

Chemical surface (in-stream/lake) water quality collection by the RVCA since 2006 (see Section 2 of this report).

Benthic invertebrate (aquatic insect) surface (in-stream) water quality collection by the RVCA in Grants Creek since 2005 (see Section 3.3.1 of this report).

Fish survey and stream characterization survey by the RVCA on Grants Creek in 2016 included taking measurements and recording observations on instream habitat, bank stability, other attributes and preparing a temperature profile (see Section 3 of this report).

Ten drainage feature assessments were conducted by the RVCA in 2017 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 of this report).

Classification of Grants Creek catchment land cover types derived by the RVCA from colour aerial photography that was acquired during the spring of 2008 and 2014 (see Section 4.1of this report).

The Mississippi Rideau Septic System Office has conducted 41 voluntary septic system re-inspections on 41 properties along Grants Creek from 2004 to 2017 (see Section 5.4 of this report).

Stewardship

Eighteen stewardship projects were completed by landowners with assistance from the RVCA (see Section 5 of this report).

Surface water quality conditions in the Grants Creek catchment are monitored by the Rideau Valley Conservation Authority (RVCA) Baseline Water Quality Monitoring Program. The baseline water quality program focuses on streams; data is collected for 22 parameters including nutrients (total phosphorus and total Kjeldahl nitrogen), E. coli, metals (like aluminum and copper) and additional chemical/physical parameters (such as alkalinity, chlorides, pH and total suspended solids). Figure 2 shows the locations of monitoring sites in the catchment.

2.1 Grants Creek: Water Quality Rating

There are six monitored water quality sites in the Grants Creek Catchment, five of which are on Grants Creek (GRT-01 to GRT-05) and one site (STA-01) on an unnamed creek crossing Stanleyville Rd (Figure 2). The RVCA's water quality rating for these sites range from "Poor" to “Very Good” (Table 1) as determined by the Canadian Council of Ministers of the Environment (CCME) Water Quality Index.

A “Poor” rating indicates that water quality is frequently threatened or impaired; conditions often depart from natural or desirable levels.  A rating of “Fair” indicates that water quality is usually protected but is occasionally threatened or impaired; conditions sometimes depart from natural or desirable levels.  A rating of "Good" indicates that only a minor degree of threat or impairment is observed and conditions rarely depart from natural or desirable levels. “Very Good" indicates water quality is protected with a virtual absence of threat or impairment; conditions are very close to natural or pristine levels.

Each parameter is evaluated against established guidelines to determine water quality conditions. Those parameters that frequently exceed guidelines are presented below. Data has been analyzed over the 2006-2017 period for general trends and conditions. Table 1 shows the overall rating for the monitored surface water quality sites within the catchment and Table 2 outlines the Water Quality Index (WQI) scores and their corresponding ratings.

The scores at these sites are largely influenced by frequent high nutrient concentrations and occasional metal exceedances. For more information on the CCME WQI, please see the Tay River Subwatershed Report.  For more information on the CCME WQI, please see the Tay River Subwatershed Report.

2.1.1 Grants Creek: Nutrients

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) is used as secondary indicators of nutrient loading. RVCA uses a guideline of 0.500 mg/l to assess TKN^[1] .

Tables 3 and 4 summarize average nutrient concentrations at monitored sites within the Grants Creek catchment and show the proportion of results that meet the guidelines.

Monitoring Site GRT-04

Site GRT-04 is the at the outflow of Pike Lake, the source of Grants Creek. Almost all (99 percent) samples at this site were below the TP guideline from 2006-2017 (Figures 3 and 4). The average TP concentration in the at this site was 0.016 mg/l (Table 3), the monthly average concentrations are fairly consistent with a slight increase observed in May samples (Figure 3). Overall a decrease was observed in TP concentrations over the 2006-2017 period^[2].

TKN concentrations show that the bulk of results (81 percent) were also below the guideline (Figure 6, Table 4). The average concentration over the 2006-2017 period was 0.439 mg/l (Table 4); monthly averages are comparable across the sampling season with the lowest concentrations observed in April and November (Figure 5).  There was no significant trend found in TKN results at this site.

Monitoring Site GRT-03

Similar nutrient conditions to site GRT-04 are observed at site GRT-03.  TP results were low, the average concentrations was 0.017 and 97 percent of samples were below the guideline (Table 3, Figure 4).  As with the upstream site the highest concentrations were observed in May, with another period of slightly elevated results (with respect to average concentrations) in November (Figure 3).

The majority of TKN results were below the guideline (Figure 5 and 6), 83 percent of samples were below 0.500 mg/l (TKN Guideline) with an average concentration of 0.450 mg/l (Table 4). Average monthly concentrations were comparable, with the exception of lower concentrations in April (Figure 5). 

A decreasing trend was observed in both TP and TKN concentrations at this site.

Monitoring Site GRT-02

Site GRT-02 is further downstream from GRT-04 and GRT-03.  While an increase in TP concentrations is observed relative to the two upstream sites (GRT-03 and GRT-04) TP concentrations may be considered low-moderate.  Seventy-four percent of samples at this site were below the TP guideline from 2006-2017 (Figures 3 and 4), and the average TP concentration in the at this site was 0.023 mg/l (Table 3). The monthly average concentrations exceeded the guideline in May and June, but are below the guideline in other months (Figure 3).  A decrease was observed in TP concentrations over the 2006-2017 period.

TKN concentrations show that the bulk of results (65 percent) were also below the guideline (Figure 6, Table 4). The average concentration over the 2006-2017 period was 0.475 mg/l (Table 4). A similar pattern to TP results is observed; monthly averages are comparable, elevated results were observed in May and June, and remaining monthly averages are below the guideline (Figure 5).  A declining trend in TKN concentrations was also found at this site.

Monitoring Site GRT-05

Moving further downstream nutrient concentrations continue to increase.  The majority of TP results (58%) are below the guideline, however, the average concentrations was elevated at 0.035 mg/l (Table 3, Figure 4).  Concentrations appear to increase from Spring through early Summer, with a second increase observed in October (Figure 3). As with other upstream sites an overall declining trend was found in TP concentrations.

The majority (49%) of TKN results were also above the guideline (Figure 5 and 6), with an average concentration of 0.559 mg/l (Table 4). Average monthly concentrations patterns were comparable with TP results, increasing from April to July, with an elevated period observed in October (Figure 5). No trend was detected in TKN concentrations at this site.

Monitoring Site GRT-01

Site GRT-01 is the last monitored site before Grants Creek meets the Tay River further downstream; increased TP concentrations continued to be observed at this site. Only 33 percent of samples were below the TP guideline from 2006-2017 (Figures 3 and 4), and the average TP concentration at this site was 0.043 mg/l (Table 3). The monthly average concentrations exceeded the guideline from May to July, with lower average concentrations into the late summer and fall (Figure 3).  A weak, significant decrease in TP concentrations was observed in the 2006-2017 data set.

TKN concentrations show that the bulk of results were also elevated (Figure 6, Table 4). Only 26 percent of samples were below the guideline, the average concentration over the 2006-2017 period was 0.595 mg/l (Table 4). As with TP data for this site, increasing monthly average concentrations were observed from April-July; concentrations in subsequent months are lower, although they still exceed the guideline (Table 3). No trend was observed in TKN concentrations over the 2006-2017 period.

Monitoring Site STA-01

This site does not drain into Grant's Creek though has been included as part of this catchment.  STA-01 monitors water quality in a small creek that drains a former waste management site along Stanleyville Rd to Pike Lake.  The majority of TP samples are elevated; only 27% of samples at this site were below the guideline from 2006-2017 (Figures 7 and 8) and the average TP concentration was 0.179 (Table 3).  the monthly average concentrations are fairly consistent with a slight increase observed in May samples (Figure 7). From data calculated for the monthly averages, concentrations increase through the summer peaking in July, after which a decrease is observed.

TKN results also show elevated concentrations are a feature of this water body. Thirteen percent of samples were also below the guideline (Figure 10, Table 4). The average concentration over the 2006-2017 period was 1.865 mg/l (Table 4).  Averaged monthly data also shows an increase from April to July in TKN concentrations followed by a decrease in the following months (Figure 9).

There was no significant trend detected in either TP or TKN results.  It should be noticed that during the late summer this creek often has very low water levels which may have impacted sampling efforts.

Summary of Grants Creek Nutrients

The data collected in Grants Creek provides evidence of nutrient enrichment downstream along the creek. Overall, there is a declining trend in TP concentrations at all sites, with a decrease in TKN observed at sites GRT-03 and GRT-02. This provides support that cumulative changes throughout the catchment have reduced nutrient loadings to the creek. This should be taken as a positive sign as high nutrient concentrations can help stimulate the growth of algae blooms and other aquatic vegetation in a water body and deplete oxygen levels as the vegetation dies off. However, elevated concentrations are still a concern in the lower reaches. Therefore, it is important to continue best management practices such as minimizing storm water runoff, enhanced shoreline buffers, minimizing/discontinuing the use of fertilizers and restricting livestock access in upstream agricultural areas to help to further reduce nutrient pollution and to continue to protect and enhance water quality conditions within Grants Creek. 

Conditions at STA-01 have remained unchanged.  As this is a very small watercourse with limited flow it is unlikely that this is having a significant impact of downstream water bodies such as Pike Lake. It should be noted that in 2011 extra sampling was done at this site, as well as upstream and downstream locations to determine sources of high nutrients and downstream impacts.  Overall results were found to be inconclusive and any elevated nutrients were attenuated by the large wetland complex downstream of this site. For more information, please contact the RVCA Surface Water Quality Coordinator.

2.1.2 Grants Creek: E. 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 water body.

Table 5 summarizes the geometric mean^[3] for the monitored sites within the Grants Creek 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 Figures 11-13 respectively.

 

Monitoring Site GRT-04

E. coli counts at site GRT-04 indicate little concern with regard to bacterial contamination. Ninety-seven percent of samples were below the guideline (Figures 11-12) and the count at the geometric mean was only 14 CFU/100ml (Table 5). Monthly E. coli counts were comparable, with lower numbers observed in April and November, likely due to cooler weather conditions which inhibits bacterial growth (Figure 12).  No trend was noted in E. coli counts over the 2006-2017 period.

Monitoring Site GRT-03

Elevated E. coli counts at site GRT-03 were uncommon. Ninety percent of samples were below the guideline (Figure 12) from 2006-2017. The count at the geometric mean was 23 CFU/100ml (Table 5) and well below the guideline, the highest counts were recorded in May (Figure 11).  As with site GRT-04 there was no significant trend in E. coli data over the 2006-2017 period.

Monitoring Site GRT-02

There is a noted increase in E. coli counts at site GRT-02 when compared to upstream sites (GRT-04 and GRT-03). Only 44% of samples were below the guideline, with a elevated count of 103 CFU/100ml at the geometric mean (Table 5, Figure 11).  Monthly E. coli counts were variable across the sampling season, often exceeding the guideline (Figure 12). As with upstream sites no trend was noted in E. coli counts over the 2006-2017 period.

Monitoring Site GRT-05

The results for the GRT-05 are comparable to neighbouring site GRT-02. Forty-six percent of samples were below the guideline (Figure 12) from 2006-2017. The count at the geometric mean was above the guideline at 109 CFU/100ml (Table 5). As with site GRT-02 monthly counts were variable and often exceeded the guideline (Figure 12), no significant trend was noted at this site.

Monitoring Site GRT-01

The results for the GRT-01 show a reduction in downstream bacterial contamination from sites GRT-02 and GRT-05. The majority of samples (61%) were below the E. coli guideline as was the count of 71 CFU/100ml at the geometric mean (Table 5).  A pattern of variable monthly counts continued to be observed (Figure 11), indicating that this data may not be strongly influenced by season.  As with other sites on Grants Creek no significant trend was noted in E. coli counts.

 

 

Monitoring Site STA-01

The results for the STA-01 show that though periods of elevated concentrations occur bacterial contamination is not a concern at this site. The majority of samples (68%) were below the E. coli guideline as was the count of 48 CFU/100ml at the geometric mean (Figure 14, Table 5).  Counts were lower in the spring and fall months likely due to cooler temperatures that inhibit bacterial growth (Figure 13).

Summary of Grants Creek Bacterial Contamination

Bacterial contamination does not appear to be a significant concern in most sections of Grants Creek.  The data does suggest that upstream of site GRT-02 and GRT-05 (and likely directly downstream) bacterial pollution may be an issue given the high proportion of samples above the guideline and elevated counts at the geometric mean.  Best management practices such as enhancing shoreline buffers, limiting livestock access and minimizing runoff in both developed and agricultural areas can help to protect water quality within Grants Creek.

2.1.3 Grants Creek: Metals

Of the metals routinely monitored in the Grants Creek Catchment, aluminum (Al) most commonly reported concentrations above its PWQO of 0.075 mg/l.  In elevated concentrations, this metals can have toxic effects on sensitive aquatic species.

Table 6 summarize metal concentrations at sites and shows the proportion of samples that meet guidelines. Figures 15 and 16 show metal concentrations with respect to the guidelines for the two periods of interest, 2006-2017.

Monitoring Site GRT-04

Aluminum concentrations at site GRT-04 show little evidence of this pollution in the upper reaches of the creek. Ninety-six percent of samples were below the guideline (Figures 15-16) with an average concentration of 0.029 mg/l (Table 6). At this site metals are only monitored in April  and August to provide information on concentrations during high and low flow conditions. A few samples have been collected during other months but please note this is a limited number (Figure 16).  No trend was noted in Al concentrations over the 2006-2017 period.

Monitoring Site GRT-03

As with the upstream site (GRT-04) elevated Al concentrations are not a feature of this site. All samples were below the guideline (Figure 16) from 2006-2017. The average concentration was 0.021 (Table 6) and well below the guideline. Metals concentrations are also only monitored in August and April (Figure 15) at this site. A few samples have been collected during other months but please note this is a limited number; no significant trend was noted in the available data.

Monitoring Site GRT-02

There is no noted increase Al concentrations at GRT-02 when compared to upstream sites (GRT-04 and GRT-03), as with upstream sites metal samples are primarily collected in April and August at GRT-02 (Figure 15). The majority of samples (97 percent) were below the guideline, an average concentration of 0.025 mg/l (Table 6, Figure 16).  As with upstream sites no trend was observed in Al concentrations over the 2006-2017 period.

Monitoring Site GRT-05

The results at site GRT-05 show a slight increase  in Al concentrations when compared to the previously discussed upstream sites.  Eighty-four percent of samples were below the guideline (Figure 16) from 2006-2017 and the average concentration was 0.042 mg/l (Table 6). Metal concentrations are monitored monthly at this site due to the increase in commercial and agricultural activity in this reach of the the creek, all monthly average concentrations were below the guideline (Figure 15).  No significant trend in Al concentration was noted at this site.

Monitoring Site GRT-01

The results for the GRT-01 show elevated Al concentration at this site (Figure 15). The majority of samples (67%) were below the Al guideline (Figure 16); however the average concentration was elevated at 0.110 mg/l (Table 6), indicating that periods of significantly elevated samples are contributing to a high overall concentration as shown in Figure 16.  As with site GRT-05, samples are collected monthly at this site; elevated concentration are observed during the majority of sampled months (Figure 15).  Overall, no significant trend was observed in Al concentrations at this site.

 

Monitoring Site STA-01

The results for the STA-01 show that few elevated samples have resulted in high average aluminum concentrations at this site. The majority of samples (79%) were below the Al guideline, however the average concentration exceeded it at 0.255 mg/l (Figure 17-18, Table 6). This site has typically only been monitored in April and August, though sampling may have occurred outside these months to capture other high or low flow events, concentrations have typically been higher during the summer months (Figure 17). There have been no significant trends in the data. Figure 18 shows that periods of very high aluminum concentrations have only been observed in 2011 and 2013; subsequent sampling has not found these high concentrations to persist at this site.

Summary of Grants Creek Metals

In the Grants Creek catchment aluminum concentrations have remained consistent through the monitoring period 2006-2017.  The majority of elevated concentrations have been observed at the two most downstream sites in Grants Creek.  This can likely be attributed of the cummulative impact of runoff within the catchment and the intensification of commercial, agricultural and developed land use upstream of these two sites (GRT-05 and GRT-01).  Runoff  due to meltwater and rainfall may pick up pollutants from farms, yards, roads and parking lots. Efforts should continue to be made to identify pollution sources and implement best management practices to reduce any inputs to improve overall stream health and lessen downstream impacts on the lower reach of Grants Creek and the Tay River. 

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The Stream Characterization Program evaluated 5.4 km of Grants Creek in 2016.  A total of 54 stream survey assessments were completed in late July and the middle of August. 

During the summer and fall of 2016, the Rideau Valley watershed experienced periods of severe drought. Precipitation levels were measured at less than 40% of the long-term average, as the water supply was unable to meet local demand. The lack of rainfall affected the success and function of farm crops, municipal and private wells, lawns and gardens, navigation and ultimately the health of our lakes, rivers and streams.

Low water conditions were readily observed throughout the watershed, as many of the streams were highly fragmented or completely dry. Aquatic species such as amphibians, fish and macroinvertebrates were affected, as suitable habitat may have been limited. Fragmentation of habitat was not observed along Grants Creek during the drought conditions in 2016, as the many large wetlands (provincially significant and unevaluated) along Grants Creek and upstream, around Pike Lake, provided critical baseflow to maintain the aquatic and riparian ecosystems (see photos below).

The quality of the riparian area increases with the width, complexity and linear extent of its vegetation along a stream or creek. A complex riparian community consists of diverse plant species native to the site, with multiple age-classes providing vertical structural diversity along a watercourse.

Here is a list of watershed benefits from a healthy riparian buffer zone:

• Reduces the amount of pollutants that reach the stream from surface runoff
• Helps reduce and mitigates erosion
• Provides a microclimate that is cooler during the summer months providing cooler water for aquatic organisms
• Provides large wood structure from fallen trees and limbs that form instream cover, create pools, stabilize
the streambed, and provide habitat for aquatic organisms
• Provides organic material for stream biota that, among other functions, is the base of the food chain
in lower order streams
• Provides habitat for terrestrial insects that drop in the stream and become food for fish and travel corridors for other terrestrial animals
• Dissipates energy during flood events
• Often provides the only refuge areas for fish during out-of-bank flows (behind trees, stumps, and logs)

Figure 19 demonstrates the buffer conditions of the left and right banks separately.  Grants Creek had a buffer of greater than 30 meters along 94 percent of the left and right banks.   

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 20). The riparian buffer zone along Grants Creek was found to be dominated by wetland and forest conditions.

3.1.3 Adjacent Land Use

The RVCA’s Stream Characterization Program identifies eight different land uses along Grants Creek (Figure 21). 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.  Wetland habitat was dominant at 67 percent; forested habitat was observed in the adjacent lands along Grants Creek at 50 percent of the surveyed sections, 35 percent scrubland and 15 percent meadow habitat.  The remaining land use consisted of active agriculture, pasture, residential and infrastructure in the form of road crossings.

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 Grants Creek had no erosion observed along the surveyed sections with only two sections having low levels of erosion in the lower reach (Figure 22).

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 23 shows that Grants Creek had no observed undercut banks along the majority of the system which is typical for systems that are dominated by riverine wetland habitat along the shoreline. 

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 24 shows low levels of stream shading along the majority of Grants Creek, which is consistent with wide open water wetland habitat conditions.  There were several sections in the upper reaches, where the channel narrows, that had high to moderate levels of stream shading along the creek.  

3.2.4 Instream Wood Structure

Forested shorelines provide essential complex habitat through the perpetual process of shoreline trees falling into the water.  This continuous recruitment of trees creates a wood-based physical structure in the littoral zone that is common on natural systems.  Insects, fish, amphibians, birds, and other animals have also evolved with this abundance of near shore wood and it is essential to their life cycles. With increased development along many waterways, forested lakeshores have been altered and wood-based physical structure in many waterways has been reduced. It is important to restore this essential habitat to aquatic ecosystems.

Shoreline Protection

• Protects shorelines by providing a barrier from wind and wave erosion
• Reduces sedimentation of the water caused by shoreline slumping due to bank erosion
• Allows detritus to collect and settle on the lake or creek bed providing the substrate structure required for native aquatic vegetation to establish and outcompete invasive species

Food Source

• Wood complexes are an important food source for invertebrates 
• Small fish feed on the abundance of invertebrates that are found around these structures
• Larger fish, waterfowl and shorebirds all benefit from the abundance of invertebrates and small fish feeding around woody structures in the littoral zone 

Cover

• Cover from predators is essential for many fish and animals to successfully complete their life cycle
• The nooks and crannies of wood complexes offer critters safety from predators while at the same time concentrating prey to make predators more efficient
• Wood provides the structure on which many species must lay or attach their eggs, therefore these complexes provide quality spawning and nesting habitat

Diversity

• Wood complexes in the littoral zone provide unique edge habitat along the shoreline
• Edge habitats contain more species diversity and higher concentrations of species than the adjoining habitats themselves will have

Figure 25 shows that the majority of Grants Creek had low to moderate levels of instream wood structure in the form of branches and trees along the system.  

3.2.5 Overhanging Wood Structure

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 26 shows the system is highly variable with no overhanging branches and trees where the system is wide and is dominated by wetland habitat to an area in the upper reach that has high levels of overhanging wood structure along Grants Creek. 

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 27 shows 70 percent of Grants Creek remains “unaltered” with no anthropogenic alterations.   Twenty two percent of Grants Creek was classified as natural with minor anthropogenic changes while seven percent was considered altered.  The alterations along Grants Creek were in the form of shoreline modifications and road crossings. 

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 Glen Tay Road since 2003 and an additional site was added on Grants Creek in 2011 immediately downstream of the Pike Lake Dam.  This site was added in 2011 as result of an identified gap in the network during the previous preparation of the 2011 Tay subwatershed report. 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 Grants Creek catchment at the Glen Tay Road and Pike Lake Dam sample locations are summarized in separate tables by year.  “Fair” to “Poor” water quality conditions were observed at the Glen Tay Road (Figure 28) and the Pike Lake Dam sample (Figure 29) locations using a grading scheme developed by Conservation Authorities in Ontario for benthic invertebrates.   

Family Richness

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 Glen Tay Road (Figure 30) and Pike Lake Dam (Figure 31) locations are reported to have “Fair” to “Good” family richness.

EPT

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 is typically mixed with species that are moderately tolerant and tolerant to poorer water quality conditions.  As a result, the EPT indicates that both of the Grants Creek samples at the Glen Tay Road (Figure 32) and Pike Lake Dam (Figure 33) locations are reported to have “Fair” to “Poor” water quality during the reporting periods.

Conclusion

Overall the Grants Creek sample locations at Glen Tay Road and Pike Lake Dam aquatic habitat conditions from a benthic invertebrate perspective are considered “Fair to Poor” as the samples are highly variable with 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 Grants Creek (Figure 34). Regions with increased habitat complexity were observed in the lower and upper reaches of the system within the catchment.  The habitat complexity was considered low within the Provincially Significant wetland along Grants Creek as defined by the criteria above, However the wetland habitat provides critical values from the following perspective; flood storage, water quality treatment, increased biodiversity and important aquatic and terrestrial habitat.

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 35 shows the overall presence of various substrate types observed along Grants Creek.  Substrate conditions were highly diverse along Grants Creek with all substrate types being recorded at various locations along the creek.  Figure 36 shows the dominant substrate type observed for each section surveyed along Grants Creek. 

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 37 shows that Grants Creek is somewhat variable; 100 percent of sections recorded runs, 28 percent pools and 15 percent riffles. Figure 38 shows where the riffle habitat areas were observed along Grants Creek.

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.  Submerged plants were present in 98 percent of the survey sections, 89 percent floating plants, 69 percent free floating plants, 67 percent broad leaved emergents, algae and robust emergents were observed in 48 percent of sections and narrow leaved emergent were observed in 43 percent of sections surveyed.  Figure 39 depicts the plant community structure for Grants Creek. Figure 40 shows the dominant vegetation type observed for each section surveyed along  Grants Creek.

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 41 demonstrates that Grants Creek reach had normal to common levels of vegetation recorded at 30 and 39 percent of stream surveys.  Extensive levels of vegetation were observed along 65 percent of the surveyed sections while twenty percent of sections had no vegetation.

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 eight percent of the sections surveyed along Grants Creek reach had invasive species. The invasive species observed in Grants Creek reach were European frogbit, Eurasian milfoil, Himalayan balsam, purple loosestrife, bull thistle, poison parsnip, Manitoba maple and banded mystery snail.  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 42).

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. 

3.3.8.1 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 43 shows that the dissolved oxygen in Grants Creek supports warmwater and in certain locations coldwater biota along the system.  The average dissolved oxygen levels observed within Grants Creek was 6.2mg/L which is above the recommended level for warmwater biota. 

3.3.8.2 Conductivity

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 Grants Creek was 185.3 µs/cm.  Figure 44 shows the conductivity readings for Grants Creek.

3.3.8.3 pH

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 along Grants Creek averaged 7.32 thereby meeting the provincial standard (Figure 45).

3.3.8.4 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:

 

Dissolved oxygen conditions on Grants Creek varied along the system for both warm and coolwater species (upper reach) (Figure 46).  There are areas within the wetland in the lower reach that fall below the guideline to support warmwater biota, however this can be common in riverine wetland habitat.

3.3.8.5 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 Grants Creek, however there were highly and moderately elevated areas in the upper reaches (Figure 47).

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 48 shows where the thermal sampling sites were located on Grants Creek.  Analysis of the data collected indicates that Grants Creek is classified as a warm water system (Figure 49). 

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

3.3.10 Groundwater

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 50 shows areas where one or more of the above groundwater indicators were observed during stream surveys and headwater assessments. 

3.3.11 Fish Community

The Grants Creek catchment is classified as a mixed community of warm and cool water recreational and baitfish fishery with 28 species observed (Figure 51). Sampling effort on Grants Creek were influenced by the 2016 drought conditions experienced in the catchment, which is the most obvious reason for the lower diversity of fish species captured.

Table 7 contains a list of fish species observed in the watershed.

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 man made, and they can be permanent or seasonal. Figure 52 shows that Grants Creek had three migration barriers they include Pike Lake Dam at the outlet of the lake as well as two weirs identified along Grants Creek at the time of the survey in 2016.

3.3.13 Beaver Dams

Overall beaver dams create natural changes in the environment. Some of the benefits include providing habitat for wildlife, flood control, and silt retention. Additional benefits come from bacterial decomposition of woody material used in the dams which removes excess nutrient and toxins. Beaver dams can also result in flooding of agricultural lands and may be potential barriers to fish migration.  Several beavers dams were observed in 2016 (Figure 53).

3.3.14 Riparian Restoration

Figure 54 depicts the locations of riparian restoration opportunities as a result of observations made during the headwater drainage feature survey assessments.   

The RVCA Stream Characterization program assessed Headwater Drainage Features for the Grants Creek catchment in 2017. 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 2017 the program sampled 10 sites at road crossings in the Grants Creek catchment area (Figure 55).   

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 Grants Creek catchment are classified as four wetland features and six were classified as channelized.  Figure 56 shows the feature type of the primary feature at the sampling locations.

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 57 shows the observed flow condition at the sampling locations in the Grants Creek catchment in 2017.

3.4.4 Feature Channel Modifications

Channel modifications were assessed at each headwater drainage feature sampling location.  Modifications include channelization, dredging, hardening and realignments.  The Grants Creek catchment area had five with no channel modifications observed, four sites as having been historically dredged/channelized and one location had mixed modifications.  Figure 58 shows the channel modifications observed at the sampling locations for Grants Creek.

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 59 depicts the dominant vegetation observed at the sampled headwater sites in the Grants Creek 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 60 depicts the type of riparian vegetation observed at the sampled headwater sites in the Grants Creek 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 substantial for the headwater sites sampled in the Grants Creek catchment area.  Figure 61 depicts the degree of sediment deposition observed at the sampled headwater sites in the Grants Creek 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 Structure 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 62 shows the feature roughness conditions at the sampling locations in the Grants Creek catchment.

Land cover and any change in coverage that has occurred over a six year period is summarized for the Grants Creek 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 Grants Creek Catchment Land Cover/Change

As shown in Table 8 and Figure 1, the dominant land cover type in 2014 is crop and pastureland.

From 2008 to 2014, there was an overall change of 38 hectares (from one land cover class to another). Most of the change in the Grants Creek catchment is a result of the conversion of crop and pastureland along with woodland to settlement (Figure 63).

Table 9 provides a detailed breakdown of all land cover change that has taken place in the Grants Creek catchment between 2008 and 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 Tay 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 64, 28 percent of the Grants Creek catchment contains 861 hectares of upland forest and six hectares of lowland forest (treed swamps) versus the 47 percent of woodland cover in the Tay 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.

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 Grants Creek catchment (in 2014), one hundred and one (64 percent) of the 159 woodland patches are very small, being less than one hectare in size. Another 48 (30 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 ten (six percent of) woodland patches range between 30 and 192 hectares in size. Nine 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 (one percent) of the 159 woodland patches in the drainage area exceed 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 17 ha) has been observed in the overall woodland patch area between the two reporting periods with most change occurring in the 20 to 50 woodland patch size class range. Six new woodland patches have been created as a result of the forest loss/gain portrayed in Figure 64, some of which has resulted in an increase in forest fragmentation across the catchment.

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 Grants Creek catchment (in 2014), the 159 woodland patches contain 15 forest interior patches (Figure 64) that occupy two percent (56 ha.) of the catchment land area (which is less than the five percent of interior forest in the Tay 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 (14) have less than 10 hectares of interior forest, nine of which have small areas of interior forest habitat less than one hectare in size. The remaining patch contains 30 hectares of interior forest. Between 2008 and 2014, there has been a small change in the number of woodland patches containing interior habitat with an overall loss of four hectares in the catchment (Table 11).

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.

This decline in wetland cover is also evident in the Grants Creek catchment (as seen in Figure 65 and summarized in Table 12), where wetland was reported to cover 34 percent of the area prior to settlement, as compared to 16 percent in 2014. This represents a 54 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.

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 66 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 Grants Creek and its tributaries in the Grants Creek catchment.

This analysis shows that the riparian zone in the Grants Creek catchment is composed of wetland (34 percent), crop and pastureland (32  percent), woodland (25 percent), settlement (five percent), roads (two percent) and meadow-thicket (one percent). Along the many watercourses (including headwater streams) flowing into Grants Creek, the riparian buffer is composed of crop and pastureland (40 percent), wetland (27 percent), woodland (26 percent), settlement areas (four percent), roads (two percent) and meadow-thicket (one percent). Along Grants Creek itself, the riparian zone is composed of wetland (56 percent), woodland (27 percent), crop and pastureland (eight percent), settlement (six percent), transportation (two percent) and meadow-thicket (one percent). Additional statistics for the Grants Creek catchment are presented in Tables 13, 14 and 15 and show that there has been very little to no change in shoreline cover from 2008 to 2014.