The News Guard
Chinese grass carp seen as vital in fight against weed
The group charged with improving the quality of water in Devils Lake is hoping to persuade the state that it needs more weed-eating Chinese grass carp to prevent the lake becoming choked with invasive species like it was in the late 1980s.
“You would think that would be pretty simple,” Lake Manager Paul Robertson said, “if grass carp were not illegal.”
The addition of more grass carp is a central strategy in the Devils Lake Water Improvement District’s newly updated Devils Lake Plan, which credits the ravenous creatures with saving the lake from weed in the late ‘80s and boosting lakefront property values in the process.
The District stocked the lake with 32,090 sterile grass carp in three batches between 1986 and 1993, with the population going on to devour the weed that had put large sections of the lake off-limits to boating.
Twenty years later, with the sterile carp dying off, then District has decided that another batch of the fish is its best bet for keeping the lake usable in the coming years.
However, the Oregon Department of Fish and Wildlife’s decision to prohibit the use of grass carp on all but small, privately owned lakes has put a significant obstacle in the District’s path.
Robertson said the District has set its sights on obtaining an exemption from the grass carp restriction and hopes that its updated strategic plan will be a tool in that process.
He said the plan shows how the District intends to deal with the underlying cause of the weed problem – excessive nutrients from a range of sources including agriculture on Thompson Creek, fertilizer from nearby lawns and failing septic tanks.
The plan details the District’s partnership with Lincoln City to implement a septic tank inspection ordinance that would, over time, require each of the 685 septic systems within the lake’s watershed to undergo an inspection every 10 years.
Robertson said the County, which started keeping records in 1974, has no records for a third of those 685 systems.
“Those are some pretty old tanks,” he said.
The District is also supporting the creating of a local improvement district that would make high-pressure sewer available to roughly 70 properties just north of Regatta Grounds, allowing owners to decommission their septic systems.
The plan also deals with what Robertson described as “the number-one pollutant in the U.S.” – storm water.
Robertson said rainwater flushes pollutants from roadways and asphalt rooftops and yards into the lake – a process that can be minimized through the use of permeable building materials that allow water to drain through into the ground.
He said natural drainage systems, such as ditches and rain gardens, allow storm water to interface with vegetation, soil and sunlight, all of which help remove nutrients before the water reaches the lake.
Other nutrient-reduction strategies in the plan include preserving wetlands and encouraging lakefront property owners to plant of native species rather than lawns
The District held a series of open houses to gather feedback on the plan, concluding with a one-hour session at its regular Feb. 3 board meeting.
Lakefront property owner Mitchell Moore welcomed the plan but warned the board to be cautious when it comes to passing ordinances in areas such as storm water mitigation and shoreline vegetation.
“People don’t like being legislated on even if it’s good cause,” he said. “The best way to do this is to first make people like what you are doing.”
Moore also urged the board to cease partnering with the City on its septic tank ordinance, which uses water shut-off as leverage, and instead work with the County to develop a program that works through the courts to gain compliance.
Several residents questioned the District’s proposal to establish a permanent educational and research center on the lake’s shore, possibly in the old Union 50 building, which is currently on the market.
Robertson said the proposed Center for Applied Freshwater Ecology, or CAFÉ, could serve as a regional resource, allowing field research on subjects including cyanobacteria as well as opening up recreational opportunities for residents and visitors.
“Think Hatfield Marine Science Center minus the salt,” he said.
Both Bill Piggott and Noel Walker took issue with the proposal, noting the Union 50 building’s listed price of $950,000.
Board Vice-chair Joe Barnes said the District has no intention of paying such a sum and would only proceed with the CAFÉ plan if it made financial sense.
The District is accepting feedback on the plan until Thursday Feb. 10, with a view to formally adopting the document at its March meeting.
For details go to the District Web site http://dlwid.org/Projects.html.