SALT LAKE CITY — A retired BYU professor and Utah Lake expert dropped a water bomb on a legislative committee Wednesday, imploring lawmakers to put a halt to upgrades at sewage plants to tackle nutrient pollution.

LaVere Merritt told the Legislature's Natural Resources, Agriculture and Environment Interim Committee that a new phosphorus rule to take effect in 2020 won't do any good to solve Utah Lake's algal bloom problems and will cost residents millions in unnecessary fee increases.

Afterward, the Wasatch Front Water Quality Council — made up of wastewater treatment plants that discharge into Utah Lake — was quick to stress that Merritt's request did not reflect its position.

"The days of doing nothing and 'prove it' are past," said Leland Myers, council chairman.

Plant operators engaged in a five-year effort to reach the decision, Myers added, and they need to act and prove to the U.S. Environmental Protection Agency that the problem of nutrient pollution is taken seriously.

"We came to the conclusion that doing nothing was not an option and good science is necessary to get right," he said.

Myers, who said Merritt is respected in the water world and an acknowledged expert, emphasized that the new rule is, indeed, not based on science but represents the purchase of time while additional research moves forward.

"We are not really looking to fight that fight," he said. "We knew the basis of that rule was not going to fix everything."

Lawmakers on the committee had no reaction to Merritt's request, and it would likely take a legislative fix to undo the rule approved by the state Water Quality Board.

Donna Spangler, spokeswoman for the Utah Department of Environmental Quality, said it wasn't clear exactly what Merritt was proposing to lawmakers, stressing it would be better for him to have that discussion with plant operators.

Nutrient reduction in the state's water bodies, particularly phosphorus, is a high priority with the agency, which is identifying headwater streams that need protection from too much of the nutrient.

Phosphorus and nitrogen, in excess, are culprits in poor water quality and are blamed in part for persistent algal blooms impacting multiple water bodies, Utah Lake in particular.

The nutrient is naturally occurring, but also a byproduct of wastewater discharge, urban runoff and agricultural activities.

Water quality regulators have been studying the issue for more than 25 years, and a new study involving multiple groups — and independently facilitated — is about to launch.

Erica Gaddis, director of the Utah Division of Water Quality, said boosting Utah Lake's water quality is critical on many levels given its recreation value and importance to the economy.

Utah Lake accounted for 57 percent of statewide lake recreation in 2012 and pumped nearly $13 million into the economy last year.

At the same time, surveys show that Utah Lake is alternately residents' most favorite lake or their least because of water quality issues, she added.