Clarity and the presence of high algae-causing nutrients have worsened water quality in parts of the Beaver Lake watershed, but overall the watershed is in good shape, according to a new report.
The Ozarks Water Watch's annual Status of the Watershed report shows the water quality improvements and conditions of 120 sites monitored within the Upper White River Basin, which runs through Northwest Arkansas and south Missouri.
Half of those sites are in the Beaver Lake watershed. The lake is the drinking water source for more than 400,000 people.
The White River flows upward from Arkansas into Missouri. That puts an emphasis on the water quality down in Arkansas.
"If we're not giving them good water, then that's more work that has to be done downstream," said Angela Danovi, regional projects director in Arkansas for Ozarks Water Watch.
Experts say less than ideal water quality is primarily the result of sediment running off land and into water. That worsens during heavy rain events, of which the area has been seeing more in recent years, said Clell Ford, executive director of the Beaver Watershed Alliance.
Northwest Arkansas is considered a "nutrient surplus area," a designation stamped on the area nearly 20 years ago after Oklahoma sued Arkansas poultry producers, alleging that excess nutrients from poultry litter applied to land was running off into the Illinois River, which flows into Oklahoma.
The label means poultry farmers must ship their litter out of the region, rather than applying it to the land. But years of algae-causing phosphorus buildup can still contribute to high phosphorus in sediment runoff.
The Ozarks Water Watch report assesses 2018 water samples, which were collected by volunteers and tested at the Arkansas Water Resources Center at the University of Arkansas, Fayetteville.
Results at one site are compared with results at other sites within the watershed to evaluate water quality. Improvement is judged based on the most recent sample compared with an average of the six years before it.
Ideally, Ozarks Water Watch could grade based on comparison results to normal levels or standards, Danovi said. However, Arkansas does not have numeric criteria for nutrients -- the state's standards are spelled out in paragraph form, explaining what should and should not be present in the water.
"Beaver Lake didn't score nearly as well as we'd like it to," Ford said. But the former manager of more than 100 lakes in Florida said the ideal water quality assessment system would compare results to similar water bodies and over several years of prior data. Natural conditions of water bodies can vary within a watershed, he said.
The Beaver Lake watershed is wide-ranging. It spans 1,182 square miles from the edges of Northwest Arkansas' principal cities to the eastern edge of Madison County.
Ozarks Water Watch gave some of the most favorable scores to sites in the Beaver Lake watershed, but it also gave some of its worst scores there.
Poorer clarity in the water and increased nitrogen prompted F grades at 10 sites out of the five dozen in the Beaver Lake watershed. But that grade combines both water quality improvement and actual measured water quality. In many of those sites, the F grade was caused by a decline in water quality, while the actual measured water quality remained fair, receiving a B or a C.
Generally, scores were worse in the southern portions of the Beaver Lake watershed, where there is less water, and better in the northern part of it, where the river gets wider and forms Beaver Lake via a dam.
The worst score was located just north of Huntsville, on Holman Creek, on the southeastern edge of the watershed. There, water quality received an F and improvement received a D. The nitrogen level was 4.6 milligrams per liter of water, up from an average of 3.8 milligrams of nitrogen per liter of water from 2012 through 2017.
That site, which is close to a wastewater treatment plant, is already considered "impaired" by the Arkansas Division of Environmental Quality. It is considered a "low" priority among the dozens of bodies of waters on the list.
Ozarks Water Watch has been looking closely at that site, Danovi said. It has lower biodiversity than anticipated.
The group, and others, have been working to improve water quality, too.
Currently, Ozarks Water Watch, the Water Conservation Resource Center and the Beaver Watershed Alliance are working with landowners in the West Fork area to reduce soil runoff from land.
The Northwest Arkansas Land Trust acquires properties in sensitive areas and looks for conservation easement opportunities, Danovi noted.
The water quality in Missouri is easier to address sometimes, Danovi said.
In Missouri, nonprofits can receive funding to repair septic systems that can contribute to water pollution. They can't in Arkansas, she said.
Danovi also recommends that during boating season people dry out their boats and clean off the hull before traveling across the watershed. Not doing so can allow species to transfer from one area of the watershed to another, where they may be less compatible with the environment.
Bull Shoals Lake had a zebra mussel outbreak a few years ago, she said, and it was nearly impossible to get them out.
Another complication in the watershed that isn't as easily addressed, Ford said, is that the region's population boom means the watershed has more pavement now.
"All of that increases the amount of speed at which that water's running off of the land," he said.
Increased velocity and energy of the water can increase the amount of runoff that ends up in the White River and its tributaries, he said.
Metro on 11/04/2019