Cumulative Effects Management of the Watershed

Stewardship groups, governments and regulatory agencies all have roles to play in the long-term management of watersheds. Watersheds are complex systems as described in State of the Watershed reports. Obviously many factors must be considered when making decisions about the future.

Using decision support tools to connect watershed variables and indicators to management goals can help to simplify problems and to identify, rank and select the most important indicators.

The linked presentation explains how the Sylvan Lake Watershed Stewardship Society has applied decision analysis to evaluate goals, set priorities and evaluate the effect of massive population expansions that are proposed in the development plans of the Sylvan Lake watershed municipalities.

This post contains reference material prepared for the Cumulative Effects Management System project which is a joint effort of member municipalities of the Sylvan Lake Management Committee and the Alberta department of Environment and Sustainable Resource Development.

The presentation graphics are posted here: Cumulative Effects Project Presentation 2012-05-18.v2

Sylvan Lake History on Display at the Archives

Marion Thompson, the volunteer office manager at the Sylvan Lake and District Archives Society invites residents to view the old photos, maps and documents at the location noted on the following brochure:

Marion Thompson can be reached by email at: or by telephone at (403)-887-6296.

Click on the image to expand it in a new window.

See Sylvan Lake history recorded in these photos:

Sylvan Lake Water Balance

Sylvan Lake exists because the last ice age created the watershed basin and because today the amount of water that enters the watershed is about the same as the amount that leaves it. The following diagram shows the inputs and outputs of water that determine the lake level and its fluctuations from year to year:

Water Balance for Sylvan Lake (AXYS 2005)

The inventory of water in the Sylvan Lake watershed is controlled by the balance between input precipitation and losses by evaporation and export. According to the analysis of multi-year data presented in the AXYS 2005 report the lake annually receives  about 20 million cubic metres (Mm3, or tonnes) of precipitation. Surface runoff adds about 11 Mm3 and subsurface groundwater flow contributes about 3 Mm3 of water.

The major loss of 31 Mm3 is by surface evaporation. Stormwater diversion easterly to Cygnet Lake and overflow through the Outlet Creek removes about 3 Mm3 of water.

Hot dry summer months accelerate evaporation and the historic record shows that the lake level can drop by up to one foot within a few weeks. Periods of cool weather and high precipitation reduce the evaporation rate and raise the lake level. In the future, increased well water extraction of groundwater for domestic use combined with pipeline export downstream to Cygnet Lake and then on to the Red Deer River has potential to disrupt the Sylvan Lake water balance. In addition, increased collection and diversion of stormwater outside the watershed by the Town of Sylvan Lake will reduce the volume of surface water entering the lake.

The figure above also includes data from the AXYS 2005 report on the input of the plant nutrients nitrogen (as the analysis Total Nitrogen, TN) and phosphorous (Total Phosphorus, TP) both of which can cause the undesirable growth of algae in the lake.

Click here for the lake level graph.

The 1978 Alberta Environment report on the regulation of the Sylvan Lake water level may be downloaded using this link: Sylvan Lake Regulation Study-AE-1978.

Sylvan Lake Newspaper and Photo Archives

This source of Sylvan Lake history is recommended by Marion Thompson of the Town of Sylvan Lake Archives.

Click on this URL to reach the Peel’s Prairie Provinces page of the University of Alberta library.

Select a tab (Newspapers or Images) and enter the keywords Sylvan Lake to retrieve records from the past.

Who remembers the old mainstreet?


Here are more photos from the archives. Click on any picture to expand the images in a full-screen viewer:

Sylvan Lake Water Quality

Sylvan Lake continues to rank in first place among the recreational lakes in Central Alberta because of its high water quality.

Please click on the graphic to enlarge it.

The lake water is sampled and analyzed periodically by Alberta Environment and Sustainable Resource Development, by the Alberta Lake Management Society (ALMS) and by the SLWSS.

The 2010 Lakewatch report by ALMS is posted here :

The detailed technical study by AXYS Environmental in 2005 “Sylvan Lake Water Quality Assessment and Watershed Management Considerations” is available for download. Note that the file size is 20 MB.

Because the concentrations of nitrogen and phosphorous (N and P) plant nutrients are low in Sylvan Lake, algae growth in the lake is minimal and the lake clarity is high. The details are reported in the Blindman River chapter of the Red Deer River Watershed Alliance master summary of the State of the Watershed.

More technical information on Sylvan Lake water quality is included in this Alberta government report “Water Quality Conditions and Long-Term Trends in Alberta Lakes“. The Sylvan Lake review starts on page 373.

Sylvan Lake Water Level

Alberta’s Environment and Sustainable Resource Development website that measures, logs and reports on the Sylvan Lake water level is now displaying data for 2012 now that the ice has melted:

Click here for the lake level graph.

Check the AESRD website regularly for the continuous updates. The same data are available as either a graph or table by clicking in the Sylvan Lake dot on this map:

Data for 2011 are shown in this graphic:

Click on the image to enlarge it in another window.

See a decade’s worth of the logged lake level data in this image gallery. Click on any image to enlarge it:

2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000

Restore the Shoreline

Since shoreline property development started at Sylvan Lake decades ago the riparian zone adjacent to the lake has changed. Government surveys classify much of that zone as “impaired”.  Property owners can help to restore some riparian zone functions by looking critically at landscaping and structures with the goal of improving water balance and reducing nutrient transfer into the lake. Simple actions like not applied fertilizer close to the lake edge, or mowing lakefront lawns that border the lake, are important.

Here’s the proposal:

SLWSS Shoreline Project

Opportunities and potential experimental shoreline sites are limited for a variety of reasons including water depth. However the Sunbreaker Cove SV has AESRD approval for a shoreline stabilization project that might include the use of aquatic plants to minimize erosion.

In general, property owners who apply to AESRD to modify the shoreline are advised to consider those techniques in combination with rip-rap installation.

Resources and advice on shoreline protection are readily available:

Shoreline Modification / Erosion Control

Caring for Shoreline Properties

Onshore measures to conserve water, improve infiltration of precipitation, and avoid erosion from storm water flow can all be applied by property owners:

Stepping back from the Water

The Native Plant Council of Alberta offers advice and cautions on plant selection:

Native Plant Council

Cows and Fish has published a Field Guide to Riparian Plants of Alberta that is available for download.