Fraser Basin Council
Home  |  CONTACT US: Offices AND Staff  |  Site Map

Flood Projects in the Thompson River Watershed


Flood hazard mapping completed in 2019-20 was intended to fill basic information gaps identified in the Thompson Watershed risk assessment. It was done at a base (screening) level, covering 478 square km across 11 floodplain sites in the Thompson-Nicola Regional District and one site in the Cariboo Regional District.

In 2020-21, the base level flood hazard mapping was updated to use the LIDAR data collected in 2019-20 for similar areas in the Thompson and Cariboo, and detailed flood mapping was completed within the City of Merritt on the Nicola and Coldwater Rivers.

The outcomes include hydrologic analysis results and screening-level flood hazard maps at a level of detail suitable for:

  • Identification of sites that may be subject to flood hazards,
  • Prioritization of sites for detailed study,
  • Conversations at the community and regional level that centre around flood risk, including mitigation strategies to reduce existing or future flood risk,
  • Emergency preparedness and response.

The outcomes of the detailed flood mapping on the Nicola and Coldwater Rivers within the City of Merritt are flood hazard scenario maps and Flood Construction Level maps within the city boundary, including the following:

  • Flood depth, velocity and intensity maps for the 20-, 50-, 100,- 200-, 500-year and 200- and 500-year climate change adjusted return period events,
  • Designated floodplain maps depicting the 200-year return period flood levels including a freeboard allowance of 0.6 m (i.e., flood construction levels).

The flood hazard mapping project in 2019-20 and the 2020-21 projects were funded by the Union of BC Municipalities Community Emergency Preparedness Fund program.

2021-2022 Project Work

FBC Detailed Flood Mapping Study:

Frequency-Magnitude Relationship for the Coldwater River

Following the November 15, 2021 flood in the Coldwater River, an urgent need emerged to estimate the peak flow of the Coldwater River to inform long-term reconstruction and mitigation efforts. The primary objective of this work was to provide a baseline estimate of the frequency-magnitude relationship for the Coldwater River at Merritt. The analysis is based on current data and methods.


Frequency-Magnitude Relationship for the Coldwater River Draft Report (May 2022)

Read the draft report


Connect & Learn Event (June 2022)

Frequency-Magnitude Relationship for the Coldwater River

Other Materials

Also see Advisory Committee for meeting summaries and related materials

2020-2021 Project Work

The following flood projects were completed in the Thompson River Watershed and other areas of the Cariboo Regional District in 2020-21, and the final products are available:

GIS and database files from the 2020 and 2021 flood mapping work are available on request for flood projects. Requests can be made to the .

Base Level Flood Mapping Sites

Watersheds flood mapping sites 2021

The above map (updated to 2021) shows the sites chosen for base-level flood hazard mapping in the Thompson-Nicola and Cariboo Regional Districts.


2019-2020 Project Work

The following flood projects were completed in Thompson River Watershed in 2019-2020, and the final project deliverables are available. 

Base-Level Flood Hazard Mapping - Final Report Available

The final report from 2020 is available for base-level flood hazard mapping in the Thompson watershed.


Flood Hazard Maps

Flood hazard map layers from this project can be accessed through an online, interactive mapping website.

Also on the site are layers from the 2018-2019 Thompson Watershed risk assessment.


LIDAR Acquisition

Click map image for larger view

Raw topographical data was collected in the Fall of 2019 using light detection and ranging (Lidar) technology, and imagery captured in almost 5000 km2 of valley bottom throughout the Thompson River Watershed.

The project data allowed for detailed, up-to-date topographic maps and will support future detailed floodplain mapping. The deliverables of the project are intended to be shared with all orders of government in the watershed.

This data can be accessed by any order of government through the BC Ministry of Forests, Lands, Natural Resource Operations and Rural Development.  to initiate a data sharing agreement and outline your geographic area of interest

This project is funded by the National Disaster Mitigation Program, funded equally by Public Safety Canada and Emergency Management BC.

Advisory Committee

A project Advisory Committee — with representation from elected officials and staff from local government, First Nations and the Province of BC — has provided guidance on this project. Information on the work of the Advisory Committee, and materials related to this work, are available: see Advisory Committee & Resources.

Learn More

For more information, contact:

Terry Robert
Director, Special Projects



Our Vision

Social well-being supported by a vibrant economy and sustained by a healthy environment.

About the Fraser Basin Council

The Fraser Basin Council (FBC) is a charitable non-profit organization that brings people together to advance sustainability in the Fraser River Basin and throughout BC. Established in 1997, FBC is a collaboration of four orders of government (federal, provincial, local and First Nations) along with those from the private sector and civil society. We work with people in multiple sectors, helping them find collaborative solutions to today’s issues through a commitment to the social, economic and environmental dimensions of sustainability. Our focus is on healthy water and watersheds, action on climate change and air quality and strong, resilient communities and regions.

FBC Project and
Partner Sites

Plug in BC:


ReTooling for Climate Change:

FBC Youth:

Climate Action Toolkit: 

Salmon-Safe BC

Contact Us

FBC has offices in Vancouver, Kamloops, Williams Lake and Prince George. We also have staff located in Abbotsford and Vernon.

To reach us, see FBC Offices and FBC Staff.

Our main office is:

Fraser Basin Council
1st Floor, 470 Granville Street
Vancouver, BC V6C 1V5

T: 604 488-5350
F: 604 488-5351

We are grateful at the Fraser Basin Council Society to live and work on the unceded ancestral
territories of the Indigenous Nations of British Columbia.