Non Point Source Pollution


NPSP is the the dumping of phosphorous into the lake from a multitude of points around the lake. This phosphorous is bound up by mother nature in the lake bottom sediment until it reaches a saturation point. At that tipping point it gets quickly released into the water. This phosphorous load causes algae to bloom.


Algae blooms make the water visibility drop to < 2 feet. It smells; and, some kinds of algae, such as the one affecting Camden, can cause very serious illness. Your property value may drop by 50% or more. Twenty years ago we had no algae blooms in Maine. Now we have 58 lakes that bloom! Lake science has advanced greatly in those 20 years. We know the process and how to stop it. Once blooming begins, it will cost several million dollars to stop it . Preventing NPSP is much cheaper and actually can add to the value of your property.


NPSP is stopped by having the water runoff from rain, roads, houses, etc. infiltrate into the ground well before it reaches the lake. The ground will filter the phosphorous out of the water. There are a number of best management practices that a homeowner or road association can use to stop NPSP in various situations. 


NPSP issues are most serious closer to the lake but can occur anywhere in our 23 square mile watershed. Waterfront taxes are 34% of town revenue so if those taxes drop because of a drop in waterfront property value then the rest of Ellsworth properties with stable property values will see a rise in their taxes to keep the total city revenue flat.


The #1 source of NPSP in Branch Lake are the gravel roads. Road maintenances must be about NPSP prevention not just drivability. The best prevention of NPSP is to have impervious road surfaces: pavement, reclaim asphalt, or stone. The runoff from these road materials is clear water. But even then, the runoff must be prevented from eroding and dissolving other soil. A ton of gravel contains pounds of phosphorous. So, muddy water (silt plus water) must be prevented from making it into the lake. It should be infiltrated into the ground. Click HERE to see the Maine DEP Camp Road Maintenance Manual full of things you and your road association should consider to protect the lake properly.


Developed lots, although less of a problem than roads, do significantly add to the phosphorous load. A developed lot can dump from 100 to 500% more phosphorous into the lake than an undeveloped lots unless mitigated using BMPs.

The Maine Lakes Society, an organization that help lake associations, has a program called LakeSmart. They list all of the BMPs and much more useful information. You can visit their website at We have trained NPSP surveyors living on the lake who can help you evaluate your own property. Contact us if you are interested in conducting a survey.

Our visibility was 32 feet just a few years ago but more recently has dropped to 21 feet. That's not bad, but not a good trend either. 


Please keep our lake clear: insist contractors get proper permits and follow BMPs; and use BMPs to improve your own property.

<Click on the BMP to pull up its detailed fact sheet>

Construction BMPs

  During construction, minimizing erosion with sediment barriers and mulching

Erosion Control Mix

  Mulching to stabilize and enrich the soil

Infiltration Steps

  Retrofitting steps to control erosion on paths

Infiltration Trench

  Managing runoff from rooftops and paved areas

Lake Shoreline Riprap

  Stabilizing severe erosion on lakefronts

Live Staking

  Stabilizing the Banks of Streams, Rivers, and Lakes

Open Top Culvert

  Diverting water off gravel roads and driveways

Paths & Walkways

  Managing foot traffic for lake protection


  Understanding environmental laws and requirements

Planting and Maintaining Buffers

  Using vegetation to protect water quality

Planting Buffer Gardens Plant List

  List of plants with photos to use in planting buffers

Rain Barrels

  Managing roof runoff in your backyard


  Diverting water off roads and driveways


  Diverting water off paths and trails

State law 420-C on erosion control applies to all roads and property construction. The process used in the law is the BMP list above. Gravel Road maintenance manual is a BMP for gravel roads. Title 38 Section 420-C

State law with definitions used in Section 420-C.