Think of a funnel: all the water that falls anywhere inside ends up at the bottom. A watershed is the land around a lake where rain, snowmelt and other water that is not absorbed into the soil runs off into the lake. Every lake has its own watershed. The water flowing into the lake may come from, or pass through to, other lakes, rivers, streams, and wetlands in the watershed.
Most of the water in a lake, river or stream comes from runoff somewhere in the watershed. Lakes also can receive water from groundwater recharge and direct precipitation.
Pollutants often attach to soil and flow with water runoff that drains into the watershed and eventually into the lake. These pollutants can include excessive phosphorus, bacteria, fertilizers and other chemicals that may harm water quality. This is called non-point source pollution because it is difficult to identify the point, or source, where the water originates in the watershed.
The source of the pollutants within the watershed could be from fields, pastured lands, over-fertilized lawns, failing septic systems, and runoff from building sites or automobile oil and other pollutants on paved areas and in roadside drainage ditches. These sources present the greatest threat to the water quality of lakes, streams and rivers in Crow Wing County.
The best way to reduce pollutants is to minimize them in runoff from the watershed. Sound land management -- both in your own backyard and within the watershed -- limits or prevents pollutants from reaching lakes and rivers.
No matter where you live, you are part of a watershed. It is up to all of us to take actions on our land to help preserve and improve the watershed's health. See next week's column for specific actions you can take.
(Sponsored by the Crow Wing County Water Planning Board and the Minnesota Lakes Association.)
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