Brad Kalb Tyson Fehringer Marie Pengilly Kristen Pilcher Montana Skovlin John Schisel Tim Barbier

 Estimate amount of aquatic vegetation in the lake  Estimate phosphorus in the lake  Estimate phosphorus stored in the plants  Explore options for remediation ◦ Cost efficient ◦ Reduce aquatic vegetation

Best Hill Ranch, Coeur d’Alene, Idaho Sampled October 7 and 14, 2009

 Aquatic vegetation ◦ Collected from 14 areas ◦ Macrophyte sampler ◦ Dried in oven for 48 hours ◦ Weighed ◦ Analyzed for phosphorus

 Aquatic vegetation ◦ ~2,700 kg (~6,000 lbs) dry mass for entire lake ◦ ~93 kg (~205lbs) phosphorus in the plants

 Estimated 659 kilograms (~1,500 lbs) total phosphorus in sediment  Plants are storing large amounts of phosphorus  Summer pump is only adding 23 grams (0.05 lbs)  Most of the phosphorus most be coming from runoff

 Physical removal ◦ Harvest in a striped pattern ◦ Raking and hand pulling ◦ Harvest when growth is at its highest ◦ 160 hours of work ◦ ~$2,000 annually

 Use strips to keep the sediment down and the water clear  Removing plants could cause an algae bloom  Use chemicals to keep algae down

 Chemicals ◦ Aquashade ◦ $70 for a gallon bottle ◦ 4 bottles ◦ $280 annually

 Decrease nutrient loading  Manual removal of macrophytes ◦ Long term removal of nutrients from system