Consultants and Alberni-Clayoquot Regional District staff view a large flood depth map at a March 10 open house at the Tseshaht First Nation Administration Building. (MIKE YOUDS/ Special to the AV News)

ACRD releases draft flood plan for Somass River watershed

Expectation is for 20 percent more rain, flooding within decades


Special to the News

A detailed draft plan for improved flood management within the Somass River watershed is available for public comment until March 24.

Developed over the last two years by a core team of about a dozen people through field surveys, flood level monitoring and hydraulic modelling, the plan provides a more complete picture of the watershed above and below the water line.

Consultants and ACRD staff shared the latest flood mapping results in a presentation Tuesday, March 10 at the Tseshaht First Nation administration building. A large flood-depth map was pieced together on the floor, indicating areas at greatest risk of flooding.

ACRD planning manager Mike Irg said previous mapping provided an incomplete picture of the area, which extends from Somass estuary to the shorelines of Sproat and Great Central lakes. New development since then, along with improved methods for predicting flood hazards, provide an up-to-date look at how the watershed functions. The plan also shows how it would react to extreme storm events, sea level rise and climate change to the year 2100.

“We’ve had events,” Irg said. “Some of the recent events have spurred us to look at what 200-year flood levels would look like.”

The Tseshaht community experiences flooding during heavy rain and high tides. There has been periodic flooding of other areas within the city as well. Rain events in 2016 and 2017 caused extensive flooding damage to properties along Sproat Lake. An extreme rain event in 2003 nearly overtopped the dam at Robertson Creek.

“It’s really starting a conversation about mitigation and where we go from here,” said Jana Zelenski of LANARC Consultants. “The more people we get studying and talking about it, the more it’s going to help us going forward.”

Hydrologist Faye Hirshfield of Northwest Hydraulic Consultants, the company that undertook the surveying and monitoring, said the plan represents riverine, coastal and lake flooding hazards but does not include tsunami flood hazards.

The climate change modelling was done with guidance from the provincial government, which uses global climate models, Hirshfield said.

“The Somass watershed will get a lot more rain by 2100, around 20 percent more,” she said. “If the rain increases 20 percent, the flow will increase 20 percent.”

The plan will serve as a tool for development and potential flood mitigation measures. The latter could include everything from alternative methods of construction, flood-proofing homes in certain areas, raising parts of Highway 4 or modifying the Sproat Lake outlet to cite a few examples.

“Engagement is really a key part of this,” Zelenski said, noting that community values may affect local decisions on flood prevention and mitigation.

After the public feedback period ends, the ACRD will share a summary of input along with finalized flood mapping and reporting. Documents supporting the plan can be viewed online at Maps can be viewed at the ACRD office by appointment. Questions and comments can be submitted via email at or by phone at 250-720-2700.

Like us on Facebook and follow us on Twitter

Alberni-Clayoquot Regional DistrictFirst Nation floodingflood mitigationPort Alberni

Get local stories you won't find anywhere else right to your inbox.
Sign up here


Consultants and Alberni-Clayoquot Regional District staff were available to answer questions behind a large flood depth map at a March 10 open house at the Tseshaht First Nation Administration Building. (MIKE YOUDS/ Special to the AV News)

The Somass River below the confluence of the Stamp and Sproat rivers during January 2020 flooding. (MIKE YOUDS/ Special to the AV News)

Just Posted

ARTS AROUND: Rollin Art Centre looking for artists to exhibit in 2021

Gallery is currently closed due to COVID-19 concerns

Scotiabank helps hockey at home

Alberni Valley Minor Hockey Association’s annual donation helps peewee teams

Agricultural Land Commission letter could halt operations at McLean Mill

National historic site near Port Alberni set to host a number of events if COVID-19 doesn’t interrupt

Mural planned for entrance to Port Alberni’s Harbour Quay

Arrowsmith Rotary project falls under the theme ‘building relationships’

City of Port Alberni to review 2020 budget in response to COVID-19

Deadline for final budget adoption is May 15

B.C. records five new COVID-19 deaths, ‘zero chance’ life will return to normal in April

Province continue to have a recovery rate of about 50 per cent

An ongoing updated list of Alberni Valley events affected by COVID-19

Has your event been cancelled or postponed? Check here

Vancouver Island’s ‘Project Draw Breath’ expands and diversifies to battle pandemic

Grassroots team working to up supplies of ventilators, other equipment during COVID-19 crisis

B.C. man sick with COVID-19 calls it a ‘horrible disease’

Tim Green says he has ‘extreme coughing fits every hour’ to clear his lungs

Trudeau says Parliament needs to sit to pass expanded COVID-19 benefits

Wage subsidy program has been greatly expanded since it was first approved

UPDATE: Anti-tax group calls for MPs, senators to donate scheduled pay raises to charity

Bill C-30, adopted 15 years ago, mandates the salary and allowance increases each calendar year

Liberals delay release of 75% wage subsidy details, costs: Morneau

Program will provide up to $847 per week for each worker

World COVID-19 update: NATO suspicious of Russian military drills; Cruise ships ordered to stay at sea

Comprehensive update of coronavirus news from around the world for Wednesday, April 1

6.5-magnitude earthquake in Idaho shakes B.C. Interior

An earthquake was reportedly felt just before 5 p.m. throughout the Okanagan

Most Read