The algae live only a few days. But bacteria feeding on dead algae consume so much oxygen that fish start dying. Last summer, water samples from near the beach in front of Ralph Johnston's home contained four times more phosphorus than normal, he said. Highland Lake is one of Maine's 41 most critically imperiled lakes, according to the state Department of Environmental Protection. One of the most prominent is China Lake in Kennebec County, which had its first major algae bloom in 1987.
Garland says it's easier to protect a healthy lake than bring a dead one back to life.
In 1971, the state required all towns to regulate building within 250 feet of lakes and prohibit construction within 100 feet. For many years, the state has recommended that towns also regulate construction within lake watersheds, but only a handful of towns have done so, said Dan Prichard, shoreland zoning coordinator for the state. Windham and Falmouth require subdivision developers to establish buffers. But a loophole in state law lets landowners divide up their land gradually in piecemeal fashion, or split it up among relatives, without ever getting planning board approval. In Windham, half of the houses are built without any town review.