3.0 Grants Creek Catchment: Riparian Conditions
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).
Grants Creek showing no apparent loss of baseflow during the drought of 2016
Grants Creek provincially significant wetland showing no apparent loss of baseflow during the drought of 2016
3.1 Grants Creek Overbank Zone
3.1.1 Riparian Buffer Land Cover 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 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.
Figure 19 Riparian Buffer Evaluation along Grants Creek
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.
Figure 20 Riparian buffer alterations along Grants Creek
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.
Figure 21 Land Use along Grants Creek
3.2 Grants 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 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).
Figure 22 Erosion levels along Grants Creek
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.
Figure 23 Undercut stream banks along Grants Creek
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.
Figure 24 Stream shading along Grants 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.
- 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
- 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 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
- 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.
Figure 25 Instream wood structure along Grants Creek
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.
Figure 26 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.
Figure 27 Anthropogenic alterations along Grants Creek
3.3 Grants 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 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.
Figure 28 Hilsenhoff Family Biotic Index at the Glen Tay Road sample location
Figure 29 Hilsenhoff Family Biotic Index at the Pike Lake Dam sample location
Family Richness measures the health of the community through its diversity and increases with increasing habitat diversity suitability and healthy water quality conditions. Family Richness is equivalent to the total number of benthic invertebrate families found within a sample. The Glen Tay Road (Figure 30) and Pike Lake Dam (Figure 31) locations are reported to have “Fair” to “Good” family richness.
Figure 30 Family Richness on Grants Creek at the Glen Tay Road sample location
Figure 31 Family Richness on Grants Creek at the Pike Lake Dam sample location
Ephemeroptera (Mayflies), Plecoptera (Stoneflies), and Trichoptera (Caddisflies) are species considered to be very sensitive to poor water quality conditions. High abundance of these organisms is generally an indication of good water quality conditions at a sample location. The community structure 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.
Figure 32 EPT on Grants Creek at the Glen Tay Road sample location
Figure 33 EPT on Grants Creek at the Pike Lake Dam sample location
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.
Figure 34 Habitat complexity along Grants Creek
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.
Figure 35 Instream substrate along Grants Creek
Figure 36 shows the dominant substrate type 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.
Figure 37 Instream morphology along Grants Creek
Figure 38 Instream riffle habitat 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.
Figure 39 Vegetation type along Grants Creek
Figure 40 Dominant instream vegetation type 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.
Figure 41 Instream vegetation abundance along Grants Creek
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).
Figure 42 Invasive species abundance along Grants Creek
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.
18.104.22.168 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.
Figure 43 Dissolved oxygen ranges along Grants Creek
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.
Figure 44 Specific conductivity ranges along Grants Creek
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).
Figure 45 pH ranges along Grants Creek
22.214.171.124 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:
Figure 46 A bivariate assessment of dissolved oxygen concentration (mg/L) and saturation (%) in Grants Creek
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.
126.96.36.199 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).
Figure 47 Relative specific conductivity levels along Grants Creek
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).
Figure 48 Temperature logger locations along Grants Creek
Figure 49 Temperature logger data for the sites on Grants Creek
Each point on the graph represents a temperature that meets the following criteria:
- Sampling dates between July 1st and September 7th
- Sampling date is preceded by two consecutive days above 24.5 °C, with no rain
- Water temperatures are collected at 4pm
- Air temperature is recorded as the max temperature for that day
Groundwater discharge areas can influence stream temperature, contribute nutrients, and provide important stream habitat for fish and other biota. During stream surveys, indicators of groundwater discharge are noted when observed. Indicators include: springs/seeps, watercress, iron staining, significant temperature change and rainbow mineral film. Figure 50 shows areas where one or more of the above groundwater indicators were observed during stream surveys and headwater assessments.
Figure 50 Groundwater indicators observed in the Grants Creek catchment
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.
Figure 51 Fish community sampling observations for 2016 in the Grants Creek catchment
Table 7 contains a list of fish species observed in the watershed.
Table 7 Fish species observed in the Grants Creek catchment
RVCA electrofishing site located on Grants Creek
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.
Figure 52 Migratory obstructions in the Grants Creek 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 beavers dams were observed in 2016 (Figure 53).
Figure 53 Beaver dam observations along Grants Creek in 2016
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.
Figure 54 Riparian restoration opportunities in the Grants Creek catchment
3.4 Headwater Drainage Feature Assessment
3.4.1 Headwaters Sampling Locations
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).
Figure 55 Location of the headwater sampling site in the Grants Creek catchment
3.4.2 Headwater Feature Type
The headwater sampling protocol assesses the feature type in order to understand the function of each feature. The evaluation includes the following classifications: defined natural channel, channelized or constrained, multi-thread, no defined feature, tiled, wetland, swale, roadside ditch and pond outlet. By assessing the values associated with the headwater drainage features in the catchment area we can understand the ecosystem services that they provide to the watershed in the form of hydrology, sediment transport, and aquatic and terrestrial functions. The headwater drainage features in the 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.
Figure 56 Headwater feature types in the Grants Creek catchment
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.
Figure 57 Headwater feature flow conditions in the Grants Creek catchment
A spring photo of the headwater sample site in the Grants Creek catchment located on Narrows Lock Road
A summer photo of the headwater sample site in the Grants Creek catchment located on Narrows Lock Road
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.
Figure 58 Headwater feature channel modifications in the Grants Creek catchment
3.4.5 Headwater Feature Vegetation
Headwater feature vegetation evaluates the type of vegetation that is found within the drainage feature. The type of vegetated within the channel influences the aquatic and terrestrial ecosystem values that the feature provides. For some types of headwater features the vegetation within the feature plays a very important role in flow and sediment movement and provides wildlife habitat. The following classifications are evaluated no vegetation, lawn, wetland, meadow, scrubland and forest. Figure 59 depicts the dominant vegetation observed at the sampled headwater sites in the Grants Creek catchment.
Figure 59 Headwater feature vegetation types 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.
Figure 60 Headwater feature riparian vegetation types 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.
Figure 61 Headwater feature sediment deposition 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.
Figure 62 Headwater feature roughness in the Grants Creek catchment