Impact of Land Use on Water

Most Albertans are supplied with treated water from surface water sources such as streams, rivers, lakes or dugouts. Surface water is also used for agricultural and industrial purposes. Freshwater aquatic life depends on an adequate supply of good quality surface water.

Land's effect on water

Side-effects

Manure, fertilizers and sewage are the major sources of nitrogen, phosphorus and bacteria contamination in Alberta surface waters. Pesticides, sediments and pharmaceuticals in runoff water from urban and rural land use may affect water quality.

Sediment is often carried in surface runoff, along with chemical pollutants. Soluble chemicals do not always percolate through the soil, resulting in increased surface runoff of soluble pollutants. Organic matter and microorganisms are also carried in surface runoff.

Water supplies contaminated with manure contain fecal coliform bacteria, such as E. Coli. Other disease-causing microorganisms such as Cryptosporidium and Giardia in drinking water can pose a threat to public health and that of livestock.

Eutrophication

Added nutrients from sewage, manure, and fertilizer runoff can lead to eutrophication, causing algae and pond scum, which interfere with water use for fisheries, recreation, industry, agriculture and drinking.

Urban land use

Urban land use results in numerous water-related issues that affect water quality and availability: high water usage, sewage and waste disposal, increased runoff from developed areas and construction sites, and runoff from the volume of lawn fertilizers and pesticides.

Energy resource industry

Pipeline construction at stream crossings can result in sediments that disturb aquatic life. Oil sands extraction has raised concern about downstream water quality and the potential for reduced flows. Heavy oil steam injection raises concerns about the volumes of groundwater used in that process. Potential contamination of aquifers used for drinking water is also a concern. Surface water has been contaminated from produced salt water being pumped into surrounding water bodies. Aquifer drawdown resulting from dewatering operations is also a concern. Coalbed methane production in Alberta may have the potential to disturb water if not adequately regulated.

Forest industry

Undisturbed forests efficiently cycle water, with very small losses to surface and groundwaters. Streams draining undisturbed forest generally have high water quality with low concentrations of dissolved nutrients and suspended sediments.

Forest management practices that disrupt nutrient cycles can increase runoff and concentrations of dissolved nutrients in adjacent streams and lakes.

Timber harvest near stream banks can increase water temperature due to removal of the forest canopy, affecting aquatic life and increasing soil erosion into streams and lakes, with a decrease in water quality. Alberta Agriculture and Forestry has provided operating ground rules for timber harvesting designed to control the impact on water.

Agricultural industry

Agriculture (irrigated agriculture in particular) is the largest single user of surface water in the province. As agricultural intensity increases so does the potential for water disturbance.

Farmland applications of pesticides and fertilizers have almost tripled in Alberta in the last 25 years. Between 1986 and 2005, cattle numbers increased by 80 per cent.

Agriculture's water pollution can be reduced through best management practices that give producers strategies to protect water quality.

More efficient irrigation methods are helping to conserve water. Efforts to more accurately match fertilizer and manure application rates to crop requirements are being designed and incorporated into agricultural operations. Cropping practices have progressed toward greater use of conservation tillage practices and the use of cover crops.

Many Alberta companies are working to reduce or recycle water in their industrial processes. Upgrading of sewage treatment has improved the quality of discharge water.

Responsible urban development and limitations on urban water use are also important. Collection and treatment of urban storm water runoff is a developing technology that will play a significant role in safeguarding water quality. Erosion control plans for construction sites have also reduced the impact of erosion and sediment movement into surface water.

 

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Updated: Sep 1, 2015