SAWMILL CREEK CATCHMENT REPORT LOWER RIDEAU RIVER SUBWATERSHED REPORT 2012 Page 19
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SAWMILL CREEK CATCHMENT LOWER RIDEAU RIVER SUBWATERSHED REPORT 2012 The RVCA produces individual reports for 16 catchments in the Lower Rideau subwatershed. Using data collected and analysed by the RVCA through its watershed monitoring and land cover classification programs, surface water quality conditions are reported for Sawmill Creek along with a summary of environmental conditions for the surrounding countryside every six years. This information is used to help better understand the effects of human activity on our water resources, allows us to better track environmental change over time and helps focus watershed management actions where they are needed the most. The following pages of this report are a compilation of that work. For other Lower Rideau catchments and Lower Rideau Subwatershed Report, please visit the RVCA website at www.rvca.ca. Inside 1. Surface Water Quality Conditions 2 Sawmill Creek 2 2. Riparian Conditions 10 Overbank Zone 10 Shoreline Zone 11 Instream Aquatic Habitat 12 3. Land Cover 17 4. Stewardship & Protection 18 5. Issues 19 6. Opportunities for Action 19 Catchment Facts Contains one municipal drain via pathway system built in conjunction with the constructed wetland Water quality rating along Sawmill Creek The lower and middle reaches of Sawmill is poor at Lester Road and poor in the Erosion control measures implemented Creek are highly urbanized and the reach from Bank Street to Walkley Road at several locations between Heron creek corridor is degraded and confined (in the vicinity of the outlet from the Road/Tax Centre Transit Station and by development and transportation Sawmill Creek constructed wetland/ Walkley Road in conjunction with infrastructure including the Airport stormwater management facility), with no Southeast Transitway construction Parkway, the Transitway and Bank change in the water quality rating Street observed over a 12 year reporting period Since 2003 the RVCA has monitored (2000-2005 vs. 2006-2011) benthic macroinvertebrates at Riverside The upper reach is undergoing Drive and since 2004, City Stream urbanization with more opportunity to Woodland cover has increased by 2.5 Watch staff and community volunteers maintain the functional integrity of the percent (52 ha.) from 2002 to 2008 have completed 16 km of stream corridor by applying development cleanup; in 2003 and 2008, stream setbacks and conveyance of the corridor Four stewardship (landowner tree surveys were undertaken by CSW staff into public ownership planting/clean water/shoreline and volunteers; between 2005 and 2008, naturalization) projects have been 1200 trees and shrubs have been Drains 21 sq. km of land or 2.7% of the completed Lower Rideau Subwatershed and 0.5% planted on and adjacent to eroding stream banks in the Heron Park area of the Rideau Valley Watershed Major studies completed include: and a pathway was relocated away from Sawmill Creek Watershed Study. 1994 the stream bank to allow for Dominant land cover is settlement (Gore & Storrie for RVCA); Sawmill revegetation; also in 2008, RVCA staff (48%), followed by transportation (21%), Creek Subwatershed Study Update. and community volunteers conducted woodland (16%), wetland (11%), 2003 (CH2MHill for City of Ottawa) grassland (3%) and water (1%) fish sampling and temperature profiling Flow diversion and constructed wetland to gain a better understanding of Riparian buffer (30 m. wide along both constructed in 2006, resulting in flood temperature and habitat variations in the sides of Sawmill Creek and its hazard reduction in South Keys, creek tributaries) is comprised of woodland stormwater treatment and reduced During 2009, the City and the University (41%), settlement (24%), wetland (17%), downstream erosion transportation (15%) and grassland (3%) of Ottawa installed stream barbs Improved public access to corridor downstream of Heron Road to direct flow Contains a cool/warm water recreational between Hunt Club and Walkley Roads away from an eroding stream bank and baitfish fishery with 21 fish species SAWMILL CREEK SURFACE WATER QUALITY CONDITIONS SAWMILL CREEK CATCHMENT LOWER RIDEAU RIVER SUBWATERSHED REPORT 2012 Page 2 1) Surface Water Quality For more information on the CCME WQI please see the Lower Rideau Subwatershed Report. Assessment of streams in the Lower Rideau is based on 24 parameters including nutrients (total phosphorus, total Table 1. WQI Ratings and corresponding index scores (RVCA Kjeldahl nitrogen, nitrates), E. coli, metals (like aluminum terminology, original WQI category names in brackets). and copper) and additional chemical/physical parameters (such as alkalinity, chlorides pH and total suspended Rating Index Score solids). Each parameter is evaluated against established Very good (Excellent) 95-100 guidelines to determine water quality conditions. Those Good 80-94 parameters that frequently exceed guidelines are presented below. Fair 65-79 Poor (Marginal) 45-64 The assessment of water quality throughout the Lower Rideau Subwatershed also looks at water quality targets Very poor (Poor) 0-44 that are presented in the 2005 Lower Rideau Watershed Strategy (LRWS), to see if they are being met. The Sawmill Creek Nutrients LRWS identifies improving water quality as a priority concern; specifically reducing the levels of nutrients, Total phosphorus (TP) is used as a primary indicator of bacteria and contaminants in the Lower Rideau. excessive nutrient loading and may contribute to abundant aquatic vegetation growth and depleted 1) a. Sawmill Creek dissolved oxygen levels. The Provincial Water Quality Objectives (PWQO) of 0.030 mg/l is used as the TP Surface water quality conditions in Sawmill Creek are Guideline. Concentrations greater than 0.030 mg/l monitored through the City of Ottawa's Baseline Water indicate an excessive amount of TP. Sawmill Creek TP Quality Program. (CK18-03-00 between Albion Road and results are shown in Figures 2a and 2b. In addition to the Aladdin Lane and CK18-S upstream side of Airport TP guideline, the Lower Rideau Watershed Strategy set Parkway off ramp bridge-culvert) (See Fig. 1 for their a target for TP concentration of 0.030 mg/l at the 85th location). percentile for tributaries of the Rideau River, such as The water quality rating for Sawmill Creek is "Poor" as Sawmill Creek. Percentile plots of TP data are shown for determined by the CCME Water Quality Index (CCME two time periods 2000-2005 (Fig. 3a) and 2006-2011 WQI); analysis of the data has been broken into two (Fig. 3b). Any point to the left of the 85th percentile line periods 2000-2005 and 2006-2011, to examine if (vertical) and above the guideline (horizontal line) have conditions have changed in this timeframe. Table 1 failed to reach the LRWS target. outlines the WQI scores and their corresponding ratings Total Kjeldahl nitrogen (TKN) is used as a secondary indicator of nutrient loading; RVCA uses a guideline of 0.500 mg/l (TKN Guideline) to assess TKN concentrations. Sawmill Creek TKN results are shown in Figures 4a and 4b. Tables 2 and 3 summarize average nutrient concentrations at monitored sites on Sawmill Creek and shows the proportion of samples that meet guidelines. Highlighted values indicate that the average has exceeded the guideline. Table 2. Summary of total phosphorous results for Sawmill Creek from 2000-2005 and 2006-2011 Total Phosphorus 2000‐2005 % Below Site Average (mg/l) Guideline No. Samples CK18‐03‐00 0.028 76 71 CK18‐S 0.041 46 39 Total Phosphorus 2006‐2011 % Below Site Average (mg/l) Guideline No. Samples CK18‐03‐00 0.033 60 65 Figure 1. Sampling sites on Sawmill Creek CK18‐S 0.039 32 62 SAWMILL CREEK SURFACE WATER QUALITY CONDITIONS SAWMILL CREEK CATCHMENT LOWER RIDEAU RIVER SUBWATERSHED REPORT 2012 Page 3 Table 3. Summary of total Kjeldahl nitrogen results for Sawmill of samples were below the guideline in the 2000-2005 Creek from 2000-2005 and 2006-2011 period this declined to thirty-two percent of samples in the 2006-2011 period. There was also a slight increase Total Kjeldahl Nitrogen 2000‐2005 in average TP concentration from 0.028 mg/l (2000- % Below 2005) to 0.033 mg/l (2006-2011). The target of a TP Site Average (mg/l) Guideline No. Samples concentration of 0.030mg/l at the 85th percentile has not CK18‐03‐00 0.832 44 71 been achieved at this site, and the concentration at the th CK18‐S 0.627 28 39 85 percentile increased from 0.041 mg/l (2000-2005, Total Kjeldahl Nitrogen 2006‐2011 Fig. 3a) to 0.050 mg/l (2006-2011, Fig. 3b). % Below Site Average (mg/l) Guideline No. Samples CK18‐03‐00 0.681 23 65 CK18‐S 0.666 6 62 Sawmill Creek Nutrients: Site CK18-03-00 The majority of samples at site CK18-03-00 were below the TP guideline of 0.030mg/l for both time periods (Fig. 2a, 2000-2005 and 2b, 2006-2011), seventy-six percent Figure 3a. Percentile plots of total phosphorous in Sawmill Creek from 2000-2005 Figure 2a. Total phosphorous concentrations in Sawmill Creek from 2000-2005 Figure 3b. Percentile plots of total phosphorous in Sawmill Creek from 2006-2011 TKN is used as a secondary indicatory of nutrient enrichment. Figures 4a, 2000-2005 and 4b, 2006-2011 show that the majority of results exceeded the TKN guideline of 0.500 mg/l, forty-four percent of samples were below the guideline in 2000-2005; this dropped to only twenty-eight percent of samples below the guideline in the 2006-2011 periods. The average Figure 2b. Total phosphorous concentrations in Sawmill Creek concentration decreased from 0.832 mg/l to 0.681 mg/l, from 2006-2011 exceeding the guideline. SAWMILL CREEK SURFACE WATER QUALITY CONDITIONS SAWMILL CREEK CATCHMENT LOWER RIDEAU RIVER SUBWATERSHED REPORT 2012 Page 4 Sawmill Creek Nutrients: Site CK18-S TKN results show that the majority of results exceeded the TKN guideline of 0.500 mg/l (Fig.