Rapid development of shorelands, exotic species, and water pollution threaten them. Phosphorus and nitrogen, washed into lakes from roads, fields, yards and septic systems, act as fertilizer for algae and weeds, turning the water green and soupy. Airborne mercury from factories, power plants and incinerators falls into our lakes. There it can build up in fish tissues, causing the state to issue advisories on how much fish anglers can safely eat from certain lakes. With more than 14,000 lakes, the MPCA can't say for sure how all or even most of them are doing.
Transparency can be a useful indicator for overall water quality.
What happens in the coming decade will be pivotal to the future of our lakes. The zoning and development decisions of local governments can have a profound effect. But so will the actions and attitudes of all of us who love to live near or play on the water. We've learned the hard way that once a lake declines, recovery can be long and expensive - when it's even possible. Prevention is key.