Changes in Water Quality Characteristics and Pollutant Sources Along a Major River Basin in Canada
Temporal and spatial variations of water quality along the Bow River (Alberta, Canada) were investigated using monthly water quality data (chloride, sulphate, nitrate, sodium, and conductivity) collected from 2004 to 2011. Non-point and point (notably three wastewater treatment plants) pollutant loads were characterized along the river. The river was divided into three reaches, namely, the Upper river reach, the Calgary reach, and the Downstream river reach, based on the distribution of point pollutant sources and geographic conditions. A mass balance approach and statistical analyses were employed to analyze water quality. The results demonstrated that the point sources, Calgary’s three wastewater treatment plants (WWTPs), are largely responsible for the observed spatial and temporal trends in the investigated quality parameters. However, the contribution of non-point sources appears to vary along the river, which might be related to the flow pathways taken by non-point pollutants discharging into the river and the geochemical characteristics of the groundwater within the alluvial aquifer that is hydraulically connected to the river. Apart from the identified point and non-point sources, the effects of other processes such as biological reactions need to be further ascertained and quantified for a better assessment of pollutant loads, in particular nutrients. Further understanding of these issues will allow a more accurate quantification of pollutant loads and consequently, better knowledge for formulating reliable water quality management strategies.
KeywordsRiver water quality variations Surface non-point pollutants Subsurface pollutants Groundwater pollutant loads Anthropogenic impacts Wastewater treatment impacts Alluvial aquifer
The authors thank the City of Calgary and Alberta Environment and Sustainable Resource Development for providing data.
- Alberta Environment River Basins (2010) Bow River at Calgary. Alberta Environment Webpage http://environment.alberta.ca/apps/basins/DisplayData.aspx?Type=Figure&BsinID=8&DataType=1&StationID=RBOWCALG. Accessed 16 Aug 2010
- Alberta Environment (2004) Alberta groundwater data, Final edn. Groundwater information centre two CD set, West of 4M and West of 5/6M, Data Current April 2003Google Scholar
- Alberto WD, Maria del Pilar D, Maria Valeria A, Fabiana PS, Cecilia HA, Maria de los Angeles B (2001) Pattern recognition techniques for the evaluation of spatial and temporal variations in water quality. A case study: Suquia River basin (Cordoba-Argentina). Water Res 35(12):2881–2894Google Scholar
- Conover WJ, Iman RL (1981) Rank transformations as a bridge between parametric and nonparametric statistics. Am Stat 35(3):124–129Google Scholar
- Environment Canada (2001) The state of municipal wastewater effluents in Canada (state of the environment report). Cat. No. En1-11/96E, ISBN 0-662-29972-8, Ottawa, ON, 74 ppGoogle Scholar
- Howard KWF, Haynes J (1993) Groundwater contamination due to road De-icing chemicals—salt balance implications. Geosci Can 20(1):1–8Google Scholar
- Iwanyshyn M, Ryan MC, Chu A (2008) Separation of physical loading from photosynthesis/respiration processes in rivers by mass balance. Sci Total Environ 390:205–214Google Scholar
- Katvala SM (2008) Isotope hydrology of the Upper Bow River Basin, Alberta, Canada. Masters Thesis, University of CalgaryGoogle Scholar
- Robinson K, Valeo C, Ryan MC, Chu A, Iwanyshyn M (2009) Modelling aquatic vegetation and dissolved oxygen after a flood event in the Bow River Alberta, Canada. Can J Civil Eng 36:492–503Google Scholar
- USGS (2005) Computer Program for the Kendall Family of trend tests. USGS report 2005–5275Google Scholar
- Winter T, Harvey J, Franke O, Alley W (1998) Groundwater and surface water a single resource. U.S. Geological Survey Circular 1139, United States Geological Survey, Denver, CO http://pubs.usgs.gov/circ/circ1139/#pdf. Accessed 16 Aug 2010