This section provides an overview on the Conditions and Indicators for the South Saskatchewan River – West sub-watershed. If you would like to learn even more about environmental and watershed indicators, we recommend “Indicators for Assessing Environmental Performance of Watersheds in Southern Alberta”

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WATER QUANTITY

South Saskatchewan River at Medicine Hat

(Station 05AJ001, Water Survey of Canada)

 

River Flow Quantity Index (RFQI)

The River Flow Quantity Index is based on the RFQI value (as reported by Alberta Environment). The River Flow Quantity Index indicator is based on the assumption that a natural average flow regime can be expected to occur about 90 per cent of the time. Otherwise, the river will be naturally at an “above average” or “below average” state. However, there will also be some periods of time where the actual recorded flow of the river will be “outside of its normal natural range” and experience significantly higher or lower levels of flow.

South Saskatchewan River (at Medicine Hat)

rfqindex2012

The following maps present different versions of the Alberta RFQI index.

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WATER QUALITY
Water Quality monitoring in this sub-watershed is performed by Alberta Environment (Station Number AB05AK0020) on the South Saskatchewan River – above (upstream) of the City of Medicine Hat.

 

River Water Quality Index

The River Water Quality Index incorporates three factors representing key aspects of water quality. The result is a number between 0 and 100 that represents the overall water quality for a location at a specific time, with 0 reflecting the worst water quality relative to the objectives and 100 the best water quality. The values are then further divided into the five descriptive categories ( Excellent, Good, Fair, Marginal, Poor).

South Saskatchewan River (at Medicine Hat)

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

River Water Quality Index

WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini WQIgreen-mini

(source: Alberta Environment, Long-term River Network site – South Saskatchewan River – located upstream of Medicine Hat, near the Highway #1 bridge)

Since 1998, the River Water Quality Index measurements indicate that overall water quality has been rated as being in “Good” condition. However, the sub-indices for both Nutrients and Pesticides have typically under-performed against the overall index, and have historically been rated in “Fair” to “Marginal” condition.

 

Read more… about water quality monitoring (2009-10) for Metals, Nutrients, Bacteria, and Pesticides.

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Other Water Quality Indicators

The other Water Quality indicators for this sub-watershed are based on the number of times that recorded measurements over a one year period “exceeded” the Water Quality Objectives (WQO) for that indicator at this location.

The rating (condition) of these water quality indicators are based on the following scale:

 

South Saskatchewan River (upstream of Medicine Hat, as of March 8, 2011)

click links below 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Water Quality Objective (WQO)

Total Dissolved Solids

TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSgreen-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini TDSblue-mini The WQO for TDS at this location is 500 mg/L

Total Phosphorus

PhosTyellow-mini PhosTred-mini PhosTyellow-mini PhosTyellow-mini PhosTyellow-mini PhosTgreen-mini PhosTgreen-mini PhosTgreen-mini PhosTyellow-mini PhosTyellow-mini PhosTgreen-mini PhosTyellow-mini PhosTyellow-mini PhosTgreen-mini PhosTgreen-mini PhosTgreen-mini PhosTgreen-mini The WQO for Total Phosphorus at this location is 0.05 mg/L

Total Nitrogen

Nyellow-mini Nyellow-mini Nyellow-mini Nyellow-mini Nyellow-mini Nyellow-mini Nyellow-mini Nyellow-mini Nyellow-mini Nyellow-mini Nyellow-mini Nred-mini Nred-mini Nyellow-mini Nyellow-mini Nyellow-mini Nred-mini The WQO for Total Nitrogen at this location is 1.0 mg/L

Bacteria: E.coli

EColiyellow-mini EColiblue-mini EColiblue-mini EColiblue-mini EColiblue-mini EColiblue-mini EColiblue-mini EColigreen-mini EColiblue-mini EColigreen-mini EColiyellow-mini EColiyellow-mini EColiblue-mini EColiblue-mini EColiblue-mini EColigreen-mini EColiblue-mini No single measurement exceeding a count of 100 E.coli per 100 mL

(source: Alberta Environment – South Saskatchewan River located above Medicine Hat (Station Number AB05AK0020)

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Phosphorus: Decline?

Since 2000, there is also some evidence of a positive trend (reduction) in recorded measurements of Total Dissolved Phosphorus, and to a lesser degree Total Phosphorous, upstream of Medicine Hat. Why is this happening?

Over time, levels of Total Dissolved Phosphorous have been significantly reduced by tertiary treatment at wastewater plants, such as those operated in Calgary and Lethbridge. Total Phosphorous, which includes Total Dissolved Phosphorous and forms of soil-bound Phosphorous which are generated from urban stormwater runoff, is still not fully controlled or treated. Other sources of Total Phosphorous come from sedimentation, erosion, and agricultural practices, but urban development and growth is the main contributor – the more hard surface and pavement – the more stormwater runoff, and hence the more Total Phosphorous which enters the river.

Alberta Environment has imposed a mandatory Total Phosphorous mass loading level within the Calgary reach of the Bow River. In response, the City of Calgary is retrofitting its stormwater retention and settling basins, and along with other stakeholders, has imposed requirements for stormwater treatment ponds on all new developments, but the benefits of these actions are still to be fully realized.

As a by product, these actions also help to reduce other pollutants, such as heavy metals oil and grease, from also making it to the river in as much quantity as occurred previously. The net result is the river’s health is improving, and this is measurable. With the exception of Total Nitrogen, most other water quality indicators in the sub-watershed have been rated as being in “Natural” or “Good” condition. This means that measurements of the various indicators recorded over a one year period did not exceed the water quality objectives for those indicators.

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Total Nitrogen: Still a Problem?

Total Nitrogen (total inorganic and organic) which is the sum of the different forms found naturally in the water, including nitrate, nitrite and ammonia, has consistently ranked poorly. Nitrogen enters surface waters naturally through the air and surface runoff, or through human activities such as wastewater discharges and agricultural practices. Elevated concentrations can result in the excessive growth of algae and aquatic plants.