The invasive quagga and zebra mussels have not been detected in McPhee Reservoir, but they're causing havoc in nearby Lake Powell.
Boat inspections at McPhee have been effective in keeping the pests out of local waters so far.
However, with shrinking budgets for Colorado Parks and Wildlife and the U.S. Forest Services, the critical checkpoints have an uncertain future.
It costs $80,000 per year to operate two boat-inspection stations at McPhee and the costs have been shared by USFS and CPW.
USFS has discontinued funding this year and possibly into the future, McPhee Reservoir officials report.
CPW recently had its budget cut by $10 million, including $1 million from the boat-inspection programs that prevent the spread of the mussels to Colorado waters.
"Funding for the boat inspection is set for 2014, but after that is not clear where the money will come from, and they will likely be asking us to chip in," said Ken Curtis, an engineer with the Dolores Water Conservancy District, at a recent board meeting.
Quagga and zebra mussels use a filter-feeding system to collect micro-organisms from the water. They invaders from Russia alter the environment by clearing up the water and upsetting the natural ecology of fresh-water lakes. They also latch onto irrigation pumps and pipes, and water treatment plants, clogging them and increasing maintenance costs.
"Currently calcium, ph levels, and nitrogen appear to be the best indicators for sustaining an infestation, and McPhee appears to meet all of those needs," Curtis said.
Colorado has had a successful prevention program, and has stopped the infestation. All Colorado reservoirs, with the exception of Pueblo Reservoir, have been de-listed from watch lists after intensive monitoring and multiple negative tests.
The state is working with Wyoming, Utah, Arizona and New Mexico to streamline prevention protocols at lakes and reservoirs.
Lake Powell is infested at two known locations that show reproducing adults have gained a foothold, Curtis said. Once in a water source, they are difficult to remove, but they require a sufficient base population to take hold.
Young mussels called veligers disperse by floating, and when they reach maturity, they attach to the lake bottom and irrigation and recreation infrastructure.
CPW oversees contract inspections at House Creek and McPhee Boat ramps from May to August, 8 a.m. to 8 p.m., and in September from 7 a.m. to 7 p.m.
Trained personnel inquire about where the boat has recently been. They inspect the boats for standing water, including the bilge pumps. If water is detected, high-pressure, hot water dispensers located at each boat launch are used to decontaminate. Upon leaving the lake, inspectors require all water be drained from the boat.
Gaps in the monitoring system are also a worry, said Jim White, a CPW aquatic biologist.
"There has been a long-standing desire to have better control over boat launches during the shoulder seasons in early spring and late fall," White said. "We have not had the financial resources to have inspectors at the ramps during these slow periods."