As previously reported, PLM is treating Clark Lake today (Monday, June 10) for the invasive weed, hybrid Eurasian water milfoil (HEWM). Lakes that did not thwart this invader found that it curtailed boating and fishing, was detrimental to the ecology, and reduced property values. Clark Lake lakefront property owners supported the establishment of a special assessment district (SAD) to turn back the invader.
The first treatment this year took place on Tuesday, May 21. Two days later, PLM took concentration samples from around the lake and sent them to the lab in North Carolina. PLM’s Steve Hanson reports the “results were excellent.” But at 5.7 parts per billion, the concentration fell short of the 6 ppb goal.
The initial treatment was delayed this year because of cooler weather. For best outcomes, a thermocline is necessary. That’s where the upper 10 to 20 feet of water is warmer than the water below, keeping the treatment product where the weeds are.
The product being installed is Sonar. Steve Hanson explains it works slowly. “It will most likely be early to mid July before the HEWM starts to die.”
Regarding today’s bump-up, there will be a 24-hour swim restriction and the same irrigation restrictions as posted with the earlier treatment. According to Steve Hanson, at “the current concentrations, there are no restrictions for lawns and ornamentals. The only restriction that may still apply is for seedling/germinating grasses.” He adds “that restriction drops off at 5 parts per billion.”
PLM posted a notice along the shoreline. Here’s what it says.