FLOOD WATCH – Urban Creeks in the City of North Bay, including Chippewa Creek.

Flood Outlook – elsewhere in NBMCA watershed

Message Number: 2024-14

Issued: Jun 21, 2024, at 4:00 PM EDT

From: NBMCA Duty Officer, Githan Kattera

FLOOD WATCH notifies that the potential for flooding exists within specific watercourses and municipalities. Municipalities, emergency services and individual landowners in flood-prone areas should prepare.

Watershed Conditions Statement - Flood Outlook: gives early notice of the potential for flooding based on weather forecasts calling for heavy rain, snow melt, high wind or other conditions that could lead to high runoff, cause ice jams, lakeshore flooding or erosion.

If you have a flood emergency, please contact your municipality. If you live in an unincorporated township, please contact the Ministry of Natural Resources and Forestry (MNRF) – North Bay District.

A FLOOD WATCH has been issued for the urban creeks in the City of North Bay.

A Watershed Conditions Statement – Flood Outlook has been issued for the remainder of the North Bay-Mattawa watershed

Current Conditions:

The Ministry of Natural Resources and Forestry has issued a Provincial Flood Watch for Northeastern Ontario in response to a forecasted low-pressure system for this weekend (Jun 22-23).

Water levels and stream flow are currently low to normal for this time of year across the watershed. Current water levels can be viewed by searching Station Names “Ottawa River”, “Mattawa River”, “Chippewa Creek”, “La Vase River”, “Wasi River”, and “Lake Nipissing” at https://wateroffice.ec.gc.ca/search/real_time_e.html

Water levels on the Ottawa River are managed by upstream dams and reservoirs operated by provincial and federal governments. Forecasts are available at https://ottawariver.ca/

The water level on Lake Nipissing is regulated by dams operated by the federal government. Forecasts are available at https://www.tpsgc-pwgsc.gc.ca/ontario/eaux-water/renseignement-information-eng.html

Forecasted Conditions:

A low-pressure system, bordered by two high-pressure systems, is forecasted to bring steady rainfall and a risk of thunderstorms over the next few days. Forecasts indicate at least 50 mm to 100 mm, or more are possible in areas with the most intense thunderstorms for Saturday (Jun 22) and Sunday.

The changes to water levels on Lake Nipissing depend on the amount of precipitation, water flowing in from rivers, and the amount of water flowing out through the control dams to the downstream French River.

Historic Flood Conditions:

For comparison during baseflow conditions, in response to intense rainfall of 25 mm in 45 minutes and a total of 37 mm on June 26, 2023, water levels on Chippewa Creek rose by 120 cm in 90 minutes. Additional rain of 53 mm on June 27 caused water levels to rise again by 108 cm, with most of the increase occurring in less than three hours.

Risk:

High-intensity and/or significant amounts of rainfall can lead to increased runoff, streamflow and flooding. Local creeks are in baseflow conditions, with water levels at or below normal for this time of year. High amounts of total rainfall and periods of high intensity rainfall can rapidly change water levels and flows, particularly in the urban areas of North Bay, including Chippewa Creek.

Widespread flooding is not expected; however, localized flooding is possible. All residents, especially those in low lying and urban areas, are encouraged to monitor the conditions as they develop and take proper precautions during periods of high flows. The public is encouraged to keep children and pets away from watercourses.

Municipalities are encouraged to monitor water crossings for debris that may affect the movement of water through culverts and bridges. A close watch on local conditions and updated forecasts and warnings from Environment Canada is also recommended.

Staff at the North Bay-Mattawa Conservation Authority will continue to monitor weather and watershed conditions and update this message based on the changing weather and streamflow conditions.

This message will be in effect until (or updated before) Monday, June 24, at 4:00 PM EDT.

The general public is advised of these messages through the www.nbmca.ca website with the flood status icon and a link to information about current conditions. NBMCA also circulates these messages to local media and social media, posting on Twitter (@theNBMCA), Instagram (nbmcainfo), and Facebook (NBMCA).

The public is invited to share photos of watershed conditions on social media using #NBMCAFlood.

Media Release issued Jun 21, 2024

https://www.nbmca.ca/watershed-management/flood-forecasting/flood-watch-status-terminology/

North Bay-Mattawa Conservation Authority Subwatershed map — *^{NBMCA Subwatershed Map}*

Lake Nipissing

Flows through the dams are based on daily analysis of the current status of the lake and river and as agreed to by the Sturgeon-Nipissing-French-Wanapitei Water Management Group. Weather forecast is considered, along with the inflows from the upper watersheds and outflows through the dam to the French River.

You can view the current level on Lake Nipissing at North Bay on the graph below and the French River at the Water Survey of Canada (WSC) website. Fluctuations in the levels are a result of the strong winds affecting the movement of surface water. Water level and flow information for the South River and Sturgeon River systems is available from Ontario Power Generation (OPG).

Flood warnings for Ontario can be found on the Ontario Flood Forecasting and Warning website.

Why the fluctuation in water level readings on Lake Nipissing? Lake Nipissing can sometimes act like a bathtub, with water shifting in the lake, depending upon wind direction, speed and atmospheric pressure - known as a wind surge or seiche. At times the wind can have such an impact that it may result in the level being higher or lower at the French River gauge compared to the gauge located on the North Bay shoreline.

Mattawa River

The current Ottawa River water level may be viewed at the Water Survey of Canada (WSC) website (note that there is a delay of several hours, and 100m should be added to the gauge reading for metres above sea level).

The Ottawa River Regulation Committee and Ontario Power Generation which operates the Otto Holden Dam provide information online regarding the management of water levels on the Ottawa River. To view water levels and current conditions on the Ottawa River visit the Ottawa River Regulation Planning Board and Ontario Power Generation.

Watercourses and Monitoring throughout the Watershed

There are other watercourses within the NBMCA jurisdiction which are monitored by NBMCA and other agencies. These gauges are maintained by Water Survey Canada - Environment Canada and can be viewed in real-time online.

In addition to the Water Survey of Canada gauges, there are other staff gauges which are monitored by NBMCA or the Ministry of Natural Resources and Forestry: