City of Calgary – Flood Readiness Newsletter – June 17, 2020 edition

June 17th, 2020 by rca_admin Leave a reply »
Flood Readiness 2020
June 17, 2020

Current river conditions (June 17, 2020) 

Despite the storm Calgary experienced last weekend, river flows remain at average, to above average, levels for this time for this time of year and we do not expect flooding over the riverbanks. The boating advisory remains in place at this time, so we ask Calgarians to be cautious around our rivers as conditions can change quickly. Check the status of the boating advisory and get more tips on how to be safe around the rivers at  calgary.ca/watersafety.

Here’s a snapshot of the current conditions:

  • The thundershowers on the weekend affected Calgary more than our river catchments to the west, and did not have much impact on flows on the Bow and Elbow Rivers. Nose Creek has been flowing high due to stormwater and runoff from its catchment north of Calgary.
  • The weather forecast for the coming week is for small amounts of rain and thundershowers. No flooding over the riverbanks is expected. As typical in spring, flows on the Bow and Elbow are fast, cold and murky. A boating advisory is in place in Calgary, and Calgarians are advised to stay off the rivers.
  • There is only snow remaining at high altitudes now, and it is within seasonal average range. With less snow remaining, melting snowpack is less of a concern for contributing to potential flooding if we get heavy rain.
  • TransAlta and Alberta Environment & Parks (AEP) are maintaining the water level in Ghost Reservoir at its target level based on current conditions.
  • The Glenmore Reservoir is being maintained at its current target of 1.7m below the crest of the dam.
  • Bow River flow at downtown Calgary this week = 220-300 m3/s (average to above average for this time of year).
  • Elbow River flow below Glenmore Dam this week = 20-40 m3/s (average to above average for this time of year).
  • The City and AEP are monitoring conditions and will update advisories if necessary.

The City of Calgary continually monitors conditions, including weather, snow pack, river and reservoir levels to prepare for potential flooding. River flows fluctuate greatly during spring, and flows up to 400 m3/s on the Bow and 100 m3/s on the Elbow are not out of the ordinary. If there is going to be a risk of flooding, we work with Alberta Environment to notify Calgarians by posting advisories online and in the media.

Advisories, river flows and reservoir levels can be checked at the Alberta Rivers website or app for iOS or Android. If there is a current advisory in place for our watershed, it will be listed in the banner at the top of the webpage/app, and our watershed will be highlighted on the map.

You can also check AEP’s weather and river flow forecasts by going to the menu at the top left (three horizontal lines) and selecting “Forecaster Comments”.

Learn more about river flow rates – what is normal, and when flooding begins, at our updated River Flow Rates webpage.

 


Responding to flash flooding

Last weekend, parts of Calgary experienced severe thunderstorm and hail causing major damage and flash flooding in many streets and communities. Thunderstorms can happen quickly, and extremely heavy rainfalls can temporarily overwhelm the storm sewers.

If you see a storm drain is clogged and you’re able to safely clear it, please do so.

If you notice water on the road or street that has not drained after 90-120 minutes, please contact 311 so our crews can quickly respond on a priority basis.

Severe thunderstorms can also lead to basement flooding. To help prevent this, ensure that your downspouts are pointed away from yours and your neighbours’ home and are directed towards lawns and gardens. Visit calgary.ca for more tips on how to reduce the risk of experiencing basement flooding, or download the Institute for Catastrophic Loss Reduction’s Handbook for Reducing Basement Flooding.


Heritage Drive Flood Barrier:  Keeping traffic moving during a flood

Heritage Drive Flood Barrier

Construction of the Heritage Drive flood barrier is complete. This almost ½ kilometre long steel barrier protects Heritage Drive S.E under the Graves Bridge (Glenmore Trail) from a 2013-level flood, ensuring the critical connection between Glenmore Trail and Deerfoot Trail remains open to emergency responders and traffic.

This is a particularly vulnerable area for Calgary. Back in 2013, this part of Heritage Drive was completely underwater during the flood. It cut off an important access road for emergency responders and the road was closed for months causing major traffic disruptions.

In 2013, the section of Heritage Trail S.E. that connects onto Glenmore Trail was engulfed in flood waters, cutting off a critical access road for emergency responders.

In 2013, the section of Heritage Trail S.E. that connects onto Glenmore Trail was engulfed in flood waters, cutting off a critical access road for emergency responders.

 

In addition to building the barrier, we have stabilized 520 metres of riverbank on the west side of the Bow River to protect against further erosion, and are adding a multi-use pathway running from the Graves Bridge parking lot to the Bonnybrook Wastewater Treatment Plant. This will complete the regional pathway on the west bank of the Bow River that extends from Downtown to the south city limits. The pathway, which also acts as a 1 in 10-year flood barrier, is expected to be open later this summer.

 

This $10.5 million project received $7 million in funding through the Province’s Flood Recovery Erosion Control and Alberta Community Resilience Programs. It’s a great example of what can be achieved when municipal and provincial governments work together to make flood mitigation a priority.

 

Find out more about other flood resilience projects complete or underway in Calgary.

 

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