Shaun Reimer at the Penticton dam regulating the water release from Okanagan Lake further south into the Okanagan Valley watershed. (OBWB photo)

Shaun Reimer at the Penticton dam regulating the water release from Okanagan Lake further south into the Okanagan Valley watershed. (OBWB photo)

Addressing conflicts in Okanagan Lake management

Analysis of existing data for setting lake levels underway

A gap analysis of data used to base decisions on managing the level of Okanagan Lake is now underway.

The ministry of environment is working with the Okanagan Basin Water Board (OBWB) on the analysis of all existing information, much of which dates back to the 1970s, used for computer modelling on what to set lake levels at, mainly during the spring and summer months.

The analysis is the first step in response to concerns registered initially by Peachland council, and since taken up by the water board. The concern is regarding how the lake level is being managed as the impact of climate change and erratic weather patterns raise flooding and drought issues for the region, along with infrastructure repair costs.

“We just started this about a week or two ago for how we deal with flooding, drought, fisheries considerations and all those other things that go into the decision-making process,” said Shawn Reimer, the section head for public safety and protection with the ministry of environment branch in Penticton.

Reimer is often called the gatekeeper of Okanagan Lake, as he manages the water release levels for the Penticton dam separating the lake from the Okanagan River, which flows to Osoyoos and across the U.S. border into Washington.

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Reimer met with the OKWB in September, as the board has sought to bring together a unified approach to how to update data used to set Okanagan Lake levels.

He said while more studies are not necessarily what Okanagan Valley watershed residents or municipal councils want to hear, it’s a process that can lead to decision-making protocols that can help limit flood damage to infrastructure and ensure farmers have sufficient access to water in drought years.

The challenge for Reimier is while winter snowfall buildup can be monitored, radical weather changes in May or June, such as a sudden wave of precipitation, are difficult to respond to, particularly when there are conflicting needs on either side of the Penticton dam.

“If you look at 2017, we had 30 centimetres of rain within a one week period and the maximum I can send water through the dam gates is 12 centimetres a day,” Reimer said.

“And if you overwhelm the southern end of the system, it raises potential flooding issues and impacts the salmon fisheries spawning which the Okanagan Nation Alliance has done so much to restore.”

He said typically Okanagan Lake peaks out by early July, but the spring rainfall bursts in both 2017 and 2018 led to that peak occurring the first week of June.

“It is the (water release) timing piece that is most troubling and certainly one you have to think about for setting target levels, taking a more conservative approach because of flooding concerns, but again in the back of your mind as well as getting caught in drought conditions further into the summer.

“The people of Vernon have different interests than do people in Oliver and we have to be aware of those differences from one end of the valley to the other.”

Reimer acknowledges if he knew the answer on how to deal with unpredictable weather conditions and multiple conflicting demands of water release on both sides of the Penticton dam, “I would be a rich man.”

“But the water board is very well positioned to really help us with this kind of situation…we are now in the very early stages of trying to tackle these potential issues around target levels, understand the thoughts that go into it. So we will see how that process unfolds.”

Okanagan