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

FLOOD WATCH - Lake Nipissing shoreline in NBMCA watershed including parts of nearby creeks

Message Number: 2023-14

Issued: May 31, 2023 at 2:00 PM EDT

From: NBMCA Duty Officer, Angela Mills

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.

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 continues for the Lake Nipissing shoreline in the NBMCA watershed including areas in North Bay along Parks Creek from Marshall Avenue to the Lake; Chippewa Creek from Main Street to the Lake; and La Vase River from Riverbend Road to the Lake.

This is an update to the previous Message Number 2023-13 dated May 24, 2023.

Current Conditions:

The water level on Lake Nipissing has decreased 10 cm since May 24 with the warm, dry weather. However, the water level on Lake Nipissing remains above the flood watch criteria. Note that strong winds can influence the water level on Lake Nipissing and result in temporary fluctuations. The water level on Lake Nipissing is regulated by dams operated by the federal government. Current water levels can be viewed by searching Station Name “Lake Nipissing” at https://wateroffice.ec.gc.ca/search/real_time_e.html

Water levels and flows in other watercourses and lakes in the NBMCA watershed are near normal for this time of year.

Forecasted Conditions:

Minimal rain is expected through June 5, with above normal air temperatures.

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

Risk:

A Flood Watch continues for the Lake Nipissing shoreline area as well as areas along Parks Creek downstream of Marshall Avenue, Chippewa Creek downstream of Main Street, and La Vase River downstream of Riverbend Road as these areas are influenced by high lake levels. The lake water level is expected to slowly decrease. Strong winds and wave action are a concern while lake levels are high. For water level and flow information, see https://www.tpsgc-pwgsc.gc.ca/ontario/eaux-water/renseignement-information-eng.html

Area residents and visitors along the Lake Nipissing shoreline, especially those in low-lying areas, are advised to monitor the conditions and take proper precautions. The public is encouraged to keep children and pets away from the shoreline and streambanks of tributaries.

Municipalities are encouraged to monitor water crossings to ensure the continual 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 if needed based on the changing weather and streamflow conditions.

This message will be in effect until Monday, June 5, 2023 at 4:00 PM EDT. No further updates will be issued unless forecasted levels or conditions necessitate change.

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), Facebook (NBMCA) and Instagram (nbmcainfo).

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

Flood Watch - Media Release - May 31, 2023

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: