February 8, 2011 Lake Bistineau Update

 

Luckily, Mother Nature is putting a pounding on the giant salvina in Lake Bistineau with sufficient cold weather.  As we observed last year, it takes several weeks for the plants to brown up and fall-out from freeze damage.  So, while giant salvinia  is still visible we expect much of what remains to dissipate by early spring.  Last year our biological staff estimated that only an acre of salvinia remained by “green-up” in early 2010.

We are receiving a lot of inquiries for information about the water levels in 2011.  Our plan is to implement water fluctuations as the plants begin to grow and expand in early summer.  Again, fluctuating the water levels is expected to strand the plants and allow for their desiccation.  Two conditions are required for this method to have desirable results.  First, their needs to be enough water in the system, or capacity to allow for sufficient water level lowering and create stranding opportunities.  Our hope is to fluctuate levels between pool stage to minus 4 feet.  Secondly, we need the plants to be in areas that are susceptible to drying out as a result of fluctuating to lower water levels.  This method is expected to offer the best method for controlling giant salvinia in the lake while saving hundreds of thousands of dollars.  We of course will be spraying aquatic herbicides appropriately.  Hopefully we can use our spraying efforts to keep the plants moving to the edges and out of the trees where matting occurs.  Once the plants mat in the trees they tend to move less and expand in coverage.  In short, it’s impossible to predict when we’ll initiate water level fluctuations.  Everything will be based on the two criteria mentioned above.

I will be providing another update next week.  This update will provide information about continued actions and new initiatives.  I’ll also recap some of the things discussed at the recent task force meeting.

Mark McElroy
Fisheries Biologist