Frank Houck, who has lived on the eastern side of Grand Lake for 20 years, remembers when he could walk the lake’s shores and see gravel at the bottom.

“You can’t see gravel anymore,” said Houck, who lives near Grove, in one of Oklahoma’s fastest-growing regions. “It’s covered with algae because of the phosphates and nitrogen that are coming into the lake. The lake is deteriorating.”

Grand Lake’s quality suffers, in part, because of runoff from agricultural operations in Missouri and Kansas. Rainwater leaving farms and factories carries high levels of phosphates, nitrates and bacteria.

The lake, a drinking water source for the region, dilutes many of the pollutants.

But their effect remains apparent.

Such quality problems figure prominently into Oklahoma’s already complicated water equation. Environmental experts and planners face this and similar issues as they rewrite the state’s water management program for 2011.

“You can have all the water in the world, but if the quality is not good, it’s like having no water at all,” said Derek Smithee, chief of water quality for the state Water Resources Board.

Skylar McElhaney, spokeswoman for the state Department of Environmental Quality, said many of the state’s water quality problems trace back to people.

“Just about everything we do threatens the quality of our water,” McElhaney said.

The department’s report on statewide water quality last year cited a host of threats to groundwater. They include animal feeding operations, brine plumes created by oil and gas industry practices and the lingering effects of old petroleum spills. Also, levels of naturally occurring arsenic spike in some overused aquifers after water levels drop.

Surface water in lakes, rivers and streams — which is ultimately connected to the groundwater supply — also is vulnerable. Government agencies monitor 4,117 bodies of water in the state. More than 530 fall short of quality standards.

The most significant threats to surface waters such as Grand Lake, environmental experts say, are pollutants washed in with rainwater runoff and snowmelt.

The problem is heightened near livestock operations. The nonprofit group Food and Water Watch, which advocates against corporate control over food and water resources, shows in an online map how locations of animal feeding centers coincide with water drainage areas with abnormally high levels of nutrients.

Some cattle farms in far western Oklahoma have been blamed for poor water quality, just as pork farms get the blame in northwestern and central Oklahoma. Attorney General Drew Edmondson has sued some poultry operations for their alleged role in fouling lakes and rivers in eastern Oklahoma.