Map of Monitoring Sites

On June 4 the Regional District of Nanaimo (RDN) Drinking Water & Watershed Protection Program (DWWP) released the 2020 report summarizing data collected by Streamkeepers groups through their Community Watershed Monitoring Program.  This was the Walley Creek Streamkeeper's fifth year participating in this program!  We use the data to better understand anthropogenic affects on the water quality, and to guide restoration efforts.  We look at the results to see where the water quality readings are exceeding standard guidelines for temperature, dissolved oxygen, specific conductance, and turbidity.   

Temperature
Walley Creek had the potential to exceed the aquatic life guideline (17 degrees Celsius) in the summer of 2019 and 2020.  This parameter is influenced by air temperature, upstream influence and physical stream attributes, however, it was noted that summer 2020 was wetter and cooler than previous years (see pg. 24 of the report).  The report suggested restoration efforts to mediate the effects of high temperature include: groundwater conservation and riparian enhancement and restoration. 

Dissolved Oxygen (DO)
The guidelines state that the average dissolved oxygen should be above 8 mg/L, and should not drop below 5 mg/L (instantaneous minimum).  Dissolved oxygen is influenced by several factors, but low DO is commensurate with high temperatures. Walley Creek was below the average in the 2020 summer monitoring period, and at Morningside Park dropped below the instantaneous minimum for the first time since we began monitoring (pg. 33).  *Check 2016 and 2017 reports to make sure this is true; the report states that it was above 5 mg/L in 2018, and 2019.    This was most likely due to low flow. 

Specific Conductivity (SpC)
Walley Creek is typically well above the guideline of 80 microsiemens(uS)/mL of SpC, the measure of dissolved ions in the water.  We believe this to be due to significant groundwater influence, as well as road runoff from the many storm drains that feed Walley Creek from adjacent residential areas.  The report states that Walley Creek was above 130 uS/cm on all 10 sampling dates (pg. 49). I don't see our data values on the graph, so I'll inquire whether there was a big difference between our summer and fall readings.  We are curious whether mitigating/absorbing road runoff would bring the SpC down, and if this would be a worthwhile activity to improve the overall water quality of Walley Creek. 

Turbidity
Measurement of suspended particles in the water exceeded parameters three times in the summer (pg. 57) and twice in the fall (pg. 58).  The fall turbidity readings correlate with significant rain events October 13 (67.3 mm) and November 3 (46.2 mm).  The report states that increased turbidity can increase temperature (pg. 51), and thereby lower dissolved oxygen.  High summer turbidity can be a result of contaminants, storm water, and erosion.  All of these are potentially true in Walley Creek.

RECOMMENDATIONS:
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Broader Recommendations, pages 28 - 30 of Community Watershed Monitoring Network Data Analysis (2011 - 2020) prepared by Ecoscape Environmental Consultants Ltd. 2021

Several of these recommendations were provided by Plewes et al. (2018) (2011 - 2017 CWMN trend report), but are included again, as they remain relevant and are important to properly document water quality conditions and to ensure watershed health.

• Conduct sampling outside of significant rainfall events, as the existing data has outliers attributable to storm events, and they can complicate statistical analyses and interpretation.
• Future analysis of the relationship between turbidity and precipitation may benefit from the use of hourly precipitation data in place of daily total precipitation. Potentially suitable networks that provide such data include: the BC Ministry of Forests, Lands, and Natural Resource Operations and Rural Development – Wild Fire Management Branch (Beaver Creek, Bowser and Cedar stations); the Ministry of Transportation and Infrastructure (Cochrane and North Courtenay stations); and the Environment Canada Qualicum Beach Airport station, which is a source of daily precipitation data assessed in this report. Any data from the listed networks would need to be assessed for accuracy, but hourly data would allow the relationship between precipitation and turbidity to be evaluated at a more granular level.
• Sample for ultra-low detection (0.002 mg/L RDL) Total and Dissolved Phosphorous, Nitrogen and Nitrates during the summer low flow period for watersheds and/or sites that have high agricultural land use, show evidence of excessive algae growth, and/or exhibit depleted DO. High agricultural use and depleted DO suggest a potential for high nutrient concentrations. Sampling for nutrients will help to confirm potential causes of low DO and will assist in the identification of critical areas for restoration and enhancement.
• Conductivity values greater than 230 μS/cm have been shown to alter fish communities (Morgan et al., 2012). Conductivity may be naturally high due to estuary or groundwater influence; however, another source of elevated conductivity is salt from paved roads/parking lots. Sites with elevated conductivity should be sampled for Chloride to determine if impervious surfaces are contributing to elevated conductivity and the potential impairment of aquatic ecosystems.
• Soil survey data from the Ministry of Environment online Soil Information Finder Tool should be utilized to better understand the natural variance in conductivity. It is expected that sites with watersheds that have more gleysols will naturally have higher conductance.
• A functional riparian habitat is critical for improved aquatic habitat values. Riparian restoration should be undertaken at all sites where the riparian habitat has been compromised and where CWMN analyte values occur outside of their respective guidelines. This is especially important for creeks that have modified adjacent land use such as agriculture and/or urban development.
• Policies for land use should consider ensuring effective implementation of agricultural buffers to separate farms from streams, where the buffers are based upon the risks associated with the farm type and the size of the watercourse. For example, a minimum 5 m buffer is often recommended between streams and cropland and a 15 m buffer for grazing. Larger buffers are encouraged for rivers and larger creeks.
• We understand that benthic invertebrate sampling following CABIN methodology has been undertaken within the various Water Regions. An assessment of the CABIN sites and how they may or may not overlap with CWMN sites would be useful. If there are overlapping sampling sites, we recommend reviewing both datasets. Together they will provide additional insights into the health of the aquatic ecosystems.
• Further to the previous point, we recommend establishing a long-term benthic monitoring program to further evaluate changes in creeks over time. Benthic sampling must occur in riffle habitat, but otherwise site selection should overlap CWMN sites, so that both datasets can be utilized. RDN should prioritize creeks for the benthic monitoring program considering key creeks that flow through a variety of land uses (e.g., agricultural, industrial, residential), the inclusion of sampling locations that are located near areas of proposed growth, as well as considerations of CWMN sites that have been identified as Sites of Concern. The City of Surrey has undertaken this type of program since the 1980s, and it has been informative to evaluate the effects of land use changes on stream health (Plewes and Olson-Russello, 2020). Their program integrates a Benthic Index of Biological Integrity (B-IBI) as a measure of biological condition. This index has been calibrated for northwestern coastal areas (e.g., Seattle and Vancouver) and it is sensitive to changes in human disturbances, but has limited inter-annual variability (Page et al., 2008).
• Trend analysis using the seasonal Mann-Kendall test should be repeated as additional years of data are added. At least six years of data is needed to look for specific trends and more data will improve the accuracy of the analysis.
• Targeted public education could be offered for areas where stormwater impacts are probable. This could involve an info mailer, adding a stencilled fish symbol to stormwater grates that report to fish-bearing streams, incentives for rain gardens, etc.
• Perform an analysis of where rain gardens would provide the greatest benefit to reduce the amount of stormwater from impervious surfaces such as roofs and parking lots. Rain gardens are an easy way to reduce the stormwater inputs to surrounding waterbodies and provide an aesthetically appealing garden that helps conserve water. Rain gardens at the municipal scale can include swales. Swales can gather and slow the infiltration of stormwater to the surrounding area. Additionally, swales can be used to direct water to rain gardens or other gardens. Rain gardens at commercial and industrial properties are also viable and can be used to adsorb or redirect runoff from large parking lots.
• Support physical assessments and stream mapping, to expand upon existing Fisheries and Oceans Canada Sensitive Habitat Inventory and Mapping (SHIM), to determine and document locations of erosion, point sources of contamination (i.e., outfalls) and priority restoration sites. This mapping is also useful for determining the quantity and quality of fish habitat and it provides a useful tool for effective long-term adaptive management. Streams should be prioritized for this mapping based on the highest level of surrounding disturbance/land uses and value of the watercourses as fish habitat.
• The provincial Riparian Areas Protection Regulation (RAPR) applies to industrial and residential development on properties within 30 m of a watercourse. Development applications via RAPR can present opportunities for riparian restoration. RDN should work with the Province to understand where riparian restoration works are occurring/proposed and how that restoration may be reflected in future CWMN sampling.