Monday, June 16, 2014

Rainfall Bow and Elbow River watersheds

Environment Canada has released a rainfall warning for portions of the watersheds for the Bow and Elbow rivers.

A low pressure system moving into the northern United States will bring significant rainfall to southern Alberta through Wednesday. The rainfall warning is calling for heavier precipitation in the Kananaskis, Canmore, Exshaw and Ghost Lake areas. The Calgary area is expecting 5-10 millimetres (mm) of rain and risks of thunderstorms daily through Wednesday.

Specifically, the Elbow River is expected to receive 30 mm of rain today and 15 mm tomorrow. This is expected to increase the flow rate into the Glenmore Reservoir 120 – 170 cubic metres per second (cms) by noon Tuesday. The seasonal norm for the Elbow River above the Glenmore Reservoir is 30 cms. During last year’s flood, the Elbow River above the reservoir peaked at 1,200 m³/s.

In anticipation of the expected increased flows, Water Services is lowering the water level in the reservoir to make room for the incoming flow. That means the outflow from the reservoir into the Elbow River will be increased to 70 – 80 cms. The seasonal norm for the Elbow River below the Glenmore Reservoir is 30 – 90 cms. During last year’s flood, the Elbow River below the reservoir peaked at 700 m³/s.

No overland flooding is expected at this time. However, this flow rate could lead to closures of pathways along the river due to some low level flooding. Pathway users are advised to watch for pathway closures and to adhere to them.

The Calgary Fire Department would like to again remind all Calgarians to avoid boating activities and to stay off both Calgary rivers.

Last month, the Calgary Fire Department issued advisories cautioning Calgarians to avoid boating activities on the Bow and Elbow Rivers due to high-flow rates and reminding them that due to 2013 Flood, debris and other changes have created unknown hazards along the rivers.

As river flows and rainfalls fluctuate, water tables can also rise and residents are reminded to ensure they safeguard any valuables in their basements, in particular those residents who have experienced basement seepage in the past. For more information about basement seepage, visit prep.

The City of Calgary, Calgary Emergency Management Agency (CEMA) and our partners, such as Environment Canada and Alberta Environment and Sustainable Resource Development (AESRD), continually monitor conditions such as snowpack, weather systems, river flow rates and ground saturation.

Alberta Environment and Sustainable Resources (AESRD) provides river forecasts. Their numbers are calibrated from information received from reporting stations. There is a two-hour delay in the information they post as it is received from various stations. The public can access the Province’s most current forecasts and forecasters’ comments.

The City of Calgary Water Services team uses the AESRD information to model forecasts and flows in order to respond as necessary to high river flows. While The City and the Province continually monitor the data, The City’s forecast is currently posted on The City’s flood information website every Monday and Thursday and shared via The City’s many communication channels.

For more information on the many ways to stay updated on conditions and understand river monitoring, visit The City’s flood information website.

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