Delavan Lake, like many in the Midwest, gets a ton of use over the summer. Yet summer is when people often unknowingly damage the very lakes they love by polluting them with phosphorous.
Phosphorous is in anything that once lived. This means soil, grass, leaves, and pet waste. Rainwater and Wisconsin snow melt can whisk the material into storm drains. It is not treated! It goes directly into Delavan Lake, feeding algae and weed growth.
Here are some tips for keeping phosphorous out of the lake:
Keep leaves, grass clippings and other lawn debris off driveways and sidewalks. Delavan ordinance prohibits putting yard waste onto city streets and sidewalks, as it not only causes phosphate runoff, but it also plugs storm sewers.
Direct downspouts into the lawn, not onto concrete. Downspouts can carry leaves from gutters. Your lawn will appreciate the extra water and nutrients.
When you spot it, remove debris from storm drains and bag it for proper disposal.
Place edging around plants so the soil stays put.
To keep soil from shifting, reseed, plant ground cover, or use wood shavings or mulch.
Clean your lawn and garden equipment over grass, not on hard surfaces where runoff can occur.
Double bag all pet waste and dispose of it in the trash.
Phosphorous also flows into the lake from lawn care products. If you're a DIYer, make sure the phosphorus content of your lawn food is as low as you can find. There are low- and no-phosphorus alternatives. If you must fertilize - avoid over fertilizing! Measure your lawn area to determine the square footage. Then calibrate your spreader to apply one-half the recommended amount of fertilizer based on the bag's label. Watch for lawn response. Reapply at the reduced rate when your lawn's response is not acceptable. More is not better. And the best time is September... not before green-up in Spring.
Delavan is proud home to some fantastic golf, and we work with the courses to make sure they're good steward to Delavan Lake by minimizing fertilization, especially in Spring. Farm fertilizers are also a concern for the lake's watershed. We work with area ag groups to minimize the amount going into Delavan Lake while still allowing our farming community to apply the essential nutrient to their cash and feed crops. Aside from conservation tillage (tilling a field less) they plant cover crops and buffers to help reduce runoff. Farm animal waste management is the biggest way they're helping keep your lake as phosporus-free as possible.