Summer is here which means the cyanobacteria — better known as blue-green algae — often found in Clark County lakes won’t be far behind. The algae blooms typically appear in the warmer months of July, August and September and are responsible for periodic closures that can last from a few days to a few weeks.
Whether it is Vancouver Lake, Lacamas Lake or another body of water, closing the lakes is especially frustrating for residents looking to escape the heat. Devan Rostorfer, manager of the county’s clean water division, said the county is working on the issue.
“Unfortunately, more and more lakes across the United States and even across the world are experiencing harmful algal blooms. It’s not just Clark County,” Rostorfer said.
The county recently held a meeting at the Port of Vancouver to reengage stakeholders working on Vancouver Lake. Those stakeholders include local, state and federal governmental agencies, as well as watershed groups. Rostorfer said everyone is working together to solve the algae bloom problem.
“The first meeting was specifically focused on developing a beach management plan for the Vancouver Lake swimming beach,” Rostorfer said.
Some of the questions the plan will address include what areas need to be treated, what monitoring data should be collected, what satellite information needs to be acquired and reviewed, and how to ensure county staff and stakeholders are ready to go when needed.
“This is the first time we’re implementing a beach management plan. Our goal is really to create this first phase as a pilot to test and evaluate the effectiveness of lake treatments so that we can learn from it and make improvements over time,” Rostorfer said.
Vancouver Lake’s wide, shallow waters are a perfect breeding ground for algae. The shape and size of the lake also makes it difficult to treat the entire lake at one time. Instead, the county will focus its efforts on specific areas. The first phase of the beach management plan calls for treating areas near the Vancouver Lake Regional Park swimming beach.
“Our focus will be on the first 150 feet from the beach out into the lake … with the goal to help protect swimmers from any potential risks from harmful algal blooms or E. coli exposure,” Rostorfer said.
But the beach management plan is a short-term solution. While it will help keep the beaches open and let swimmers take a dip, the county needs a long-term fix.
“The lake still needs to be studied to determine what the best plan of action is. Implementing a more widespread treatment at Vancouver Lake is not only more complicated but also more costly,” Rostorfer said.
Lakewide solutions could require treating the water column, the area from the lake bed to the water’s surface, or the sediment where more nutrients are stored. Other solutions could involve replacing the existing culverts or adding habitat enhancements to help reconnect Burnt Bridge Creek, Salmon Creek or Lake River to improve lake flushing.
Lacamas Lake
Where Vancouver Lake’s algae blooms are fed by a variety of nutrients coming from residential neighborhoods and even some agricultural runoff, Lacamas Lake’s blooms are being fed by phosphorus.
“What people do at home has an impact downstream. Everyone can play a role in clean water,” Rostorfer said.
The county is working with the city of Camas on managing Lacamas Lake. The two jurisdictions recently signed an interlocal agreement for lake management, with Camas serving as the lead for implementing treatments this summer.
“The plan for lake treatment at Lacamas Lake is to treat the water column to help take out the phosphorus that causes harmful algal blooms to happen,” Rostorfer said.
She said the city and county are working together to collect the data needed to make the best treatment decisions.
“What’s most important in treating Lacamas Lake is that we time it right to make sure that we’re implementing the treatment when the most phosphorus is being released into the water,” she said.
Where is the phosphorus coming from? Rostorfer said the majority is coming from Lacamas Creek, a 68-square-mile area that starts near Brush Prairie and runs through Hockinson and other rural parts of the county.
Similar to Vancouver Lake, the common sources of phosphorus include septic systems, agricultural runoff and runoff from residential areas, which can contain fertilizers, insecticides and household chemicals.
