OSSIPEE — Pollution control starts in one's own backyard, according to officials involved with watershed protection in the region.

Dustin Johnson, program manager for the Acton Wakefield Watersheds Alliance, who directs its Youth Conservation Corps, and John Shipman, chair of the Ossipee Watershed Coalition, gave separate presentations on water quality and pollution control during the Ossipee Lake Alliance Lake Representatives Forum 2012 Saturday at Ossipee Town Hall.

A key point during Johnson's session was that how homeowners handle stormwater runoff – and how often they pump their septic tanks – can impact water bodies downhill.

Johnson, explaining that a watershed is land that drains to a body of water, said the Ossipee Lake watershed encompasses approximately 200 square miles. He said whether a homeowner lives on the shore or up in the hills, what they do on their property has a direct impact on the lake.

“When it rains, pollution happens,” Johnson said.

Since its inception six years ago, the Acton Wakefield Watersheds Alliance, through its Youth Conservation Corps, has implemented 130 erosion and runoff control projects that has prevented an estimated 310 tons of sediment from reaching lakes in Wakefield, Johnson said. Projects ranged from installing rain gardens to capture stormwater runoff, to installing drip-line trenches, drywells, and steps made with crushed gravel.

Johnson said pollution is more acute in areas of more paved surfaces.

“With paved surfaces, the dynamic changes drastically. Now 55 percent of the rain is runoff, carrying petroleum, oil, trash, cigarette butts,” he said.

Pollution prevention tips include avoiding the use of fertilizer, planting vegetation in yards and on the shoreline and using erosion control mulches, among others.

Shipman said environmental health, community health and economic health are connected. He said builders, developers and homeowners should follow best management practices regarding stormwater runoff and potential phosphorous pollution. Doing something as simple as emptying one's septic system every three to five years and installing stormwater runoff control measures can prevent phosphorous from flowing directly into the lakes.

“The problem is phosphorous. Phosphorous is our enemy,” said Shipman. “It encourages plant growth” like algae and milfoil. Shipman urged communities to conduct continuous water quality monitoring and to prepare watershed management plans.

Shipman and Johnson noted “point source” pollution has drastically decreased since the Clean Water Act was passed decades ago, outlawing the piping of raw sewage and waste into lakes and rivers.

The main problem currently is stormwater runoff and erosion, Shipman said.

“Where does runoff come from? Everywhere,” he said. What happens is phosphorous from detergents, fertilizer and other products drains into the soil and sticks to the sediment that makes its way downstream or downhill to the lake.

Overall, phosphorous levels in Ossipee Lake are at acceptable levels in most areas, with a few spots where levels are higher.

lmulkern@newstote.com