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We have all watched the algae recently overtake our wonderful lakes. The Lake Arrowhead Lakes Committee is tackling the problem with a new lake management firm and program, but we can’t succeed without your help. Those large algae blooms are an indication that there is too much of the nutrient phosphorus in the lake waters. Our goal is to get rid of the algae blooms, and encourage a healthy lake ecosystem with native lakeshore and aquatic plants instead.


  1. Use phosphate-free fertilizer (mandated in Denville and Mountain Lakes) or, even better, don't use any fertilizer. Just one lb. of phosphorus produces 500 lbs. of algae!!!
    How can you tell? Fertilizer bags have three numbers on them, for the percentage of nitrogen, phosphorus and potassium, respectively. A middle ZERO (0) means it’s phosphorus-free. A licensed lawn care service should be following both Mountain Lakes and Denville ordinances and using phosphorus-free fertilizer - but ask!
  2. Don’t use any fertilizer within 10’ of the lakes - as also mandated in Denville’s ordinance.
  3. Minimize the use of broad-leafed herbicides (like Round-up) and pesticides, which end up in the lake and kill the healthy lake plants and animals. Better yet, don’t use them at all.
  4. Aggressively manage your leaves and yard waste: rake as soon as they fall so the run-off from the decomposing leaves can’t feed the algae. If you live on the lake, trim back branches hanging over the water. The leaves sink to the bottom and decompose, which makes the lake shallower and warmer, and adds nutrients, all of which accelerate algae growth.
  5. Clean up after your pets - and geese - those droppings also feed the algae.
  6. Plant native trees and shrubs instead of lawns. Runoff from lawns carries 8 times more phosphorus into the lake than runoff from wooded areas. Less mowing too!! Why native? They are hardy, spread fast and don’t require fertilizer or pesticides. See
  7. If you live on the lake, plant a buffer zone of native trees, shrubs, grasses and wildflowers between your lawn and the lake to filter the polluted/fertilizer run-off. Encourage native water plants along your shoreline to help filter polluted runoff, and provide important habitat for turtles, fish and frogs. The geese will be discouraged from your lawn, too! What's a buffer zone? See to get started.
  8. Build a rain garden with native plants and wildflowers to absorb runoff before it gets to the lakes. What’s a rain garden? See
  9. Minimize paved driveways and walkways, which can’t absorb run-off.

You live in the Lake Arrowhead watershed, so everything that is put or left on your property (lawn/driveway) eventually gets washed into the lakes. The quality of our lakes is a reflection of how well we all take care of our properties, and keeping the lakes beautiful and ecologically healthy will result in higher property values for all homeowners in the watershed.

Visitour our Rsource Center for additional information on watershed area management practices that you may want to review.  The information packets will describe: how to cultivate your native plant rain garden and/or your lakeside buffer zone, if you have lakefront property; what our newly hired lake management company is doing: and the Lakes Committee's nutrient mitigation and testing activities. 

If you have any questions, please feel free to give Lake Chairman or any Lake Committee member a call!