3.0 Eagle Lake Catchment: Riparian Conditions

The Stream Characterization Program evaluated 2.7 km of Eagle Creek in 2016.  A total of 27 stream survey assessments were completed in the middle of July. 

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 observed in sections along Eagle Creek during drought conditions in 2016.

3.1 Eagle Creek Overbank Zone

3.1.1 Riparian Buffer Evaluation

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 34 demonstrates the buffer conditions of the left and right banks separately.  Eagle Creek had a buffer of greater than 30 meters along 100 percent of the left bank and 94 percent of the right bank.   

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 35). The riparian buffer zone along Eagle Creek was found to be dominated by forest, wetland and scrubland conditions.  There was an area in the middle reach along the right bank that had altered riparian zone conditions.

3.1.3 Adjacent Land Use

The RVCA’s Stream Characterization Program identifies eight different land uses along Eagle Creek (Figure 36). 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 78 percent of sections surveyed; forested habitat was found at 74% of sections, 19 percent scrubland habitat, while seven percent was classified as meadow habitat in the adjacent lands along Eagle Creek.  The remaining land use consisted of active agriculture, residential, recreational and infrastructure in the form of road crossings.

3.2 Eagle Creek 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 Eagle Creek had no evidence of erosion observed along the surveyed sections, however there were three locations with low levels of erosion observed (Figure 37).

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 38 shows that Eagle Creek had no observed undercut banks along the upper and lower reaches of the system, however there were several sections in the middle reaches with low levels of undercut banks.

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 39 shows highly variable levels of stream shading along Eagle Creek.  There were many sections along the creek where the channel narrows that had high to moderate levels of stream shading along the system.  

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 40 shows that the majority of Eagle Creek had high to moderate levels of instream wood structure along the system.   Low to moderate levels of in water trees and branches were observed along the majority of 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 wood structure provide a food source, nutrients and shade which helps to moderate instream water temperatures.  Figure 41 shows the system is highly variable with no overhanging branches and trees where the system is wide and is dominated by wetland habitat to areas in the middle reaches that have high levels of overhanging wood structure along Eagle 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 42 shows seventy four percent of Eagle Creek remains “unaltered” with no anthropogenic alterations.   Nineteen percent of Eagle Creek was classified as natural with minor anthropogenic changes while seven percent was considered altered.  The alterations along Eagle Creek were in the form of shoreline modifications and road crossings.  There were no sections that were classified as being highly altered.

3.3 Eagle Creek 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 Bobs Lake Road site since 2011.  The Eagle Creek sample location was added to the monitoring network as a result of an identified gap during the release of the 2011 Eagle Creek catchment 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 Eagle Creek catchment at the County Road 38 sample location is summarized by year.  “Poor” water quality conditions were observed at the Eagle Creek sample location (Figure 43) 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 Bobs Lake Road sample location is reported to have “Fair” family richness (Figure 44).

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 somewhat variable with samples that are dominated by species that are tolerant to poorer water quality conditions at the Eagle Creek site location.  As a result, the EPT indicates that the Eagle Creek sample location is reported to have conditions that range from “Fair” to “Poor” water quality (Figure 45) during the reporting period.

Conclusion

Overall the aquatic habitat conditions for the Eagle Creek sample location at Bobs Lake Road from a benthic invertebrate perspective ranges from “Fair” to “Poor” conditions as the samples have species that are more tolerant to high organic pollution levels during most years.

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 Eagle Creek (Figure 46). Regions with increased habitat complexity were observed in the middle and lower reaches of the system within the 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 47 shows the overall presence of various substrate types observed along Eagle Creek.  Substrate conditions were highly diverse along Eagle Creek with all substrate types being recorded at various locations along the creek. Figure 48 shows the dominant substrate type observed for each section surveyed along Eagle 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 49 shows that Eagle Creek is highly variable; 93 percent of sections recorded runs, 33 percent pools and 30 percent riffles. Figure 50 shows where the riffle habitat areas were observed along Eagle 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. Algae was observed in 93 percent of sections, submerged plants were present in 81 percent of the survey sections, 74 percent for floating plants, narrow leaved emergents were observed in 59 percent of sections, 26 percent free floating plants, 63 percent broad leaved emergents and robust emergents were observed in 37 percent of sections surveyed.  Figure 51 depicts the plant community structure for Eagle Creek. Figure 52 shows the dominant vegetation type observed for each section surveyed along Eagle 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 53 demonstrates that Eagle Creek reach had normal to common levels of vegetation recorded at 41 and 48 percent of stream surveys.  Extensive levels of vegetation were observed in 63 percent of the surveyed sections, while 19 percent of sections had areas with 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 six percent of the sections surveyed along Eagle Creek reach had invasive species. The invasive species observed in Eagle Creek were European frogbit, purple loosestrife, banded mystery snail and common/glossy buckthorn.  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 54).

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 55 shows that the dissolved oxygen in Eagle Creek supports warmwater and in certain locations coldwater biota along the system.  The average dissolved oxygen level observed within Eagle Creek was 5.2mg/L which is below the recommended level for warmwater biota.  The lower and middle reaches of Eagle Creek were within the threshold to support warmwater biota.  The upper reaches fell below the recommended threshold to support warmwater aquatic 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 Eagle Creek was 166.8 µs/cm.  Figure 56 shows the conductivity readings for Eagle 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 Eagle Creek averaged 7.21 thereby meeting the provincial standard (Figure 57).

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 Eagle Creek were somewhat variable along the system (Figure 58).  Sections in the upper reach fell below the guideline to support warmwater biota, however sections in the middle and lower reaches were acceptable for warm/cool water species.

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 Eagle Creek; however there was an area in the middle reach and in the extreme lower reach with high and moderate levels of conductivity (Figure 59).

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 60 shows where the thermal sampling sites were located on Eagle Creek.  Analysis of the data collected indicates that Eagle Creek is classified as a warm water system with cool-warm water reaches (Figure 61). 

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 62 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 Eagle Creek catchment is classified as a mixed community of warm, cool and cold water recreational and baitfish fishery with 16 species observed.  The following is a list of species observed in the watershed in 2016 and historically (Figure 63). There was a significant reduction in species richness observed in 2016 likely as a result of drought conditions, which can alter species distribution along the creek. 

Table 16 contains a list of 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 manmade, and they can be permanent or seasonal. Figure 64 shows the migration barriers along Eagle Creek at the time of the survey in 2016.  There were five perched culverts and one debris dams along Eagle Creek and various headwater drainage features within the catchment.

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 beaver dams were identified along Eagle Creek in 2016 as well as two on headwater drainage features in the catchment (Figure 65).

3.4 Headwater Drainage Feature Assessment

3.4.1 Headwaters Sampling Locations

The RVCA Stream Characterization program assessed Headwater Drainage Features for the Eagle Lake catchment in 2016. 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 2016 the program sampled 14 sites at road crossings in the Eagle Lake catchment area (Figure 66).  

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 Eagle Lake catchment are all classified as natural and wetland features.  Figure 67 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 68 shows the observed flow condition at the sampling locations in the Eagle Lake catchment in 2016.

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 Eagle Lake catchment area had a majority of features with no channel modifications with the exception of one site having mixed modifications.  Figure 69 shows the channel modifications observed at the sampling locations for the Eagle Lake catchment.

3.4.5 Headwater Feature Vegetation

Headwater feature vegetation is classified into the following types: no vegetation, lawn, wetland, meadow, scrubland and forest. The type of vegetation 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. Figure 70 depicts the dominant vegetation observed at the sampled headwater sites in the Eagle Lake 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 71 depicts the type of riparian vegetation observed at the sampled headwater sites in the Eagle Lake catchment.  The majority of the headwater drainage features are classified as having natural riparian vegetation with only one feature having altered vegetation.

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 Eagle Lake catchment area.  Figure 72 depicts the degree of sediment deposition observed at the sampled headwater sites in the Eagle Lake catchment.  Sediment deposition conditions ranged from no sediment deposition to extensive.

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, wood 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 73 shows that the feature roughness conditions at the sampling locations in the Eagle Lake catchment were highly variable ranging from minimal to extreme.