2. Surface Water Quality Conditions

Surface water quality conditions in the Dales Creek catchment are monitored by the Rideau Valley Conservation Authority’s (RVCA) Baseline Water Quality Monitoring Program. The Baseline Water Quality Program focuses on streams; data is collected for 22 parameters including nutrients (total phosphorus, total Kjeldahl nitrogen and ammonia), E. coli, metals (like aluminum and copper) and additional chemical/physical parameters (such as alkalinity, chlorides, pH and total suspended solids). Figure 1 shows the location of the monitoring site in the catchment. 

Dales Creek Water Quality

Water Quality Rating

The water quality ratings for the Dales Creek catchment is “Fair” (Table 1) as determined by the Canadian Council of Ministers of the Environment (CCME) Water Quality Index and is largely influenced by high nutrient concentrations, metals and high bacterial counts. A "Fair" rating indicates that water quality is usually protected but is occasionally threatened or impaired; conditions sometimes depart from natural or desirable levels. Each parameter is evaluated against established guidelines to determine water quality conditions. Those parameters that frequently exceed guidelines are presented below. Analysis of the data has been broken into two periods; 2003 to 2008 and 2009 to 2014 for the stream monitoring site located on Dales Creek (DAL-01) to examine if conditions have changed between these periods. Table 1 shows the overall rating for the monitored surface water quality site within the Dales Creek catchment and Table 2 outlines the Water Quality Index (WQI) scores and their corresponding ratings.

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) and ammonia (NH3) are used as secondary indicators of nutrient loadings. RVCA uses a guideline of 0.500 mg/l to assess TKN^[1] and the PWQO of 0.020 mg/l to assess NH3 concentrations in Dales Creek.

Tables 3, 4 and 5 summarize average nutrient concentrations at monitored sites within the Creek catchment and show the proportion of results that meet the guidelines.

Elevated TP results were an occasional occurrence in the 2003-2008 and 2009-2014 monitoring periods at site DAL-01. The 2009-2014 monitoring period saw a marginal improvement with less exceedances. Site DAL-01 had 83 percent of samples that were below the guideline in the 2003-2008 period (Figure 2); this increased to 89 percent of samples in the 2009-2014 period (Figure 3). The average TP concentration for both reporting periods were below the PWQO which slightly decreased from 0.021 mg/l to 0.020 mg/l (Table 3).

Figure 2 Total Phosphorous concentrations in Dales Creek, 2003-2008

Figure 3 Total phosphorous concentrations in Dales Creek, 2009-2014

 

TKN concentrations show that the bulk of results exceeded the guideline (Figures 4 and 5); there were few samples (15 percent) below the guideline in the 2003-2008 period and this slightly increased to 19 percent in the 2009-2014 period. The average concentration was generally elevated and increased from 0.663 mg/l to 0.737 mg/l (Table 8).

Figure 4 Total Kjeldahl nitrogen concentrations in Dales Creek, 2003-2008

Figure 5 Total Kjeldahl nitrogen concentrations in Dales Creek, 2009-2014

 

Occasional elevated nutrients were observed in NH3 data. The proportion of results that were below the guideline were 82 percent in 2003-2008 (Figure 6); this decreased to 75 percent in the 2009-2014 reporting periods (Figure 7). The average NH3 concentration slightly increased from 0.007 mg/l to 0.008 mg/l (Table 5).

Figure 6 Ammonia concentrations in Dales Creek, 2003-2008

Figure 7 Ammonia concentrations in Dales Creek, 2009-2014

 

Summary

The data shows that nutrient enrichment is a feature of Dales Creek. Total phosphorous and NH3 occasionally exceed the guidelines while TKN concentrations frequently exceeded the guideline. Elevated TKN concentrations may be influenced by organic matter held by wetland areas found upstream in the Middle Rideau Subwatershed, resulting in naturally high concentrations of organic nitrogen. High nutrient concentrations can help stimulate the growth of algae blooms and other aquatic vegetation in a waterbody and deplete oxygen levels as the vegetation dies off. It is important to reduce human impacts wherever possible. Strategies to reduce nutrient inputs may include diversion of runoff to the creek and enhanced shoreline buffers.

E. 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 waterbody.

Table 6 summarizes the geometric mean^[2] for the monitored site on Dales Creek 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 for the two periods, 2003-2008 and 2009- 2014, are shown in Figures 8 and 9 respectively.

E. coli results at site DAL-01 indicate bacterial counts are occasionally above the E. coli guideline. The proportion of samples below the guideline increased from 34 percent (Figure 8) to 51 percent (Figure 9). E.coli counts decreased slightly between the two monitoring periods (2003-2008 and 2009-2014) with a geometric mean of 81 CFU/100ml to 79 CFU/100ml (Table 6).

Figure 8 Geometric mean of E.coli counts in Dales Creek, 2003-2008

Figure 9 Geometric mean of E.coli counts in Dales Creek, 2009-2014

 

Summary

This data shows that E.coli results occasionally exceed the guidelines at site DAL-01 in Dales Creek. The geometric mean is below the PWQO for both monitoring periods and there has been a decrease in E.coli counts between 2003-2008 and 2009-2014. Properly maintaining septic systems, enhancing shoreline buffers and restricting cattle access can help to improve E.coli levels in Dales Creek.

Metals

Of the metals routinely monitored in Dales Creek, aluminum (Al), iron (Fe) and copper (Cu) occasionally reported concentrations above their respective PWQOs. In elevated concentrations, these metals can have toxic effects on sensitive aquatic species.

Tables 7, 8 and 9 summarize metal concentrations at site DAL-01 and show the proportion of samples that meet guidelines. Figures 10 to 15 show metal concentrations with respect to the guidelines for the two periods of interest, 2003–2008 and 2009–2014. For Al, the PWQO is 0.075 mg/l, Cu it is 0.005 mg/l and Fe it is 0.300 mg/l.

Results from DAL-01 show that Al concentrations had few exceedances with 85 percent of samples below the guideline in the 2003-2008 period (Figure 10). This improved to 100 percent of samples in the 2009-2014 period (Figure 11). The average concentration of Al was 0.046 mg/l from 2003-2008 and 0.010 mg/l from 2009-2014 which are both below the guideline. 

Figure 10 Average aluminum concentrations in Dales Creek, 2003-2008 

Figure 11 Average aluminum concentrations in Dales Creek, 2009-2014

 

Copper concentrations occasionally exceeded the PWQO, with 89 percent of samples below the guideline in 2003-2008 (Figure 12). This decreased to 84 percent of samples being below the guideline in 2009-2014 (Figure 13). The average concentration of Cu was 0.002 mg/l for both reporting periods (Table 8). 

Figure 12 Average copper concentrations in Dales Creek, 2003-2008

Figure 13 Average copper concentrations in Dales Creek, 2009-2014

 

Iron concentrations also surpassed the PWQO guideline. The proportion of samples below the guideline increased from 89 percent to 96 percent (Figures 14 and 15). Although there were observed exceedances, the average concentration did not exceed the guideline in both monitoring periods; 0.225 mg/l in 2003-2008 and .071 mg/l in 2009-2014. 

Figure 14 Average iron concentrations in Dales Creek, 2003-2008

Figure 15 Average iron concentrations in Dales Creek, 2009-2014

Summary

Overall, a general decline in metal concentrations was observed between the two periods of interest, with the exception of copper which slightly increased. Efforts should continue to be made to identify pollution sources and implement best management practices to reduce any inputs such as runoff, metal alloys, fungicides and pesticides to improve overall stream health and lessen downstream impacts.