Sea gulls, heavy snowfall, and an outlet structure stuffed with silt have renewed concerns about water quality in Liberty Lake.
During his annual lake monitoring report last week, Washington State University researcher William Funk updated sewer district officials and local residents on the success of their ongoing effort to maintain a healthy body of water.
The shallow lake - about 30 feet at its deepest - over the years has suffered from pollution, algae blooms, thick coverings of scum and other problems, said Funk, director of the Water Research Center at WSU.
The lake’s restoration, which has involved construction of a sewer system, the creation of requirements for developers, such as mandated storm water retention ponds, even the establishment of an annual debris cleanup, has been highly successful, said Funk, who has studied the lake for three decades.
Still, he said, Liberty Lake is fragile and will always require attention and maintenance.
Due to heavy snowfall last winter and subsequent heavy melts this spring, Liberty Lake’s water level is high and water is flushing back and forth over the dike that separates the lake from a nutrient-rich marsh.
That increases nitrogen and phosphorus levels in the lake, which contributes to algae blooms that cover the lake and produce large amounts of scum.
Liberty Lake, which suffered numerous blooms in the 60s and 70s, has experienced just two since its restoration. Those took place in 1988 and 1996.
“We have a lot of nutrients (now),” he said.
The high water wouldn’t be as much of a problem if the lake’s outlet structure wasn’t clogged with silt. The outlet leads to the sump, where excess water is filtered and drained away.
Liberty Lake Sewer District No. 1 will need to clear the structure, Funk said.
The nutrient problem is exacerbated by plentiful sea gulls, which just aren’t considerate enough to wear diapers.
As many as 6,000 sea gulls roost on the lake each evening, Funk said, and the waste the birds produce is considerable. It takes just three gulls to produce waste equivalent to that from one human.
Funk thinks the gulls may have once made their homes at the old Greenacres and Mica landfills. When those facilities closed, Liberty Lake became one of their hot night spots.
Reducing its popularity among the birds is a challenge that stumps even Funk.
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