LOWELL, AR — For the past 11 years, hundreds of citizen scientists and others have collected water quality data on Beaver Lake near Rogers in Northwest Arkansas during the annual Secchi Day event, typically held on the third Saturday each August. The big question on everyone’s minds is whether there are any trends that can be identified, now that there’s over a decade of data to consider. To put it simply, how is the water quality in Beaver Lake doing?
Dr. Bob Morgan, Manager of Environmental Quality for Beaver Water District (BWD), shared data and comments about Secchi Day with BWD Board members during their regularly scheduled meeting held at noon on Oct. 27. Data from this year’s event, held on Aug. 20, was included in that presentation.
“We have enough data after 11 years that we can identify some apparent trends,” Morgan said. “For example, the lake is getting clearer in the uppermost end and the mid-lake area, and the down-lake area is slightly cloudier. However, statistical analysis of these data gives little confidence that these apparent trends are real. Practically speaking, there is not a significant trend in late summer clarity over the 11 years of Secchi Day. That’s a good thing. That’s what we want to see because it implies that the educational programs and the management practices implemented by concerned people in the Beaver Lake watershed are helping to maintain water quality.
“With the changes taking place in Northwest Arkansas, and specifically expansion of the urban area into the Beaver Lake watershed, science tells us that we will experience more stress on our natural resources. Secchi Day is but one day out of 365 each year. Beaver Water District, the United States Geological Survey, the Arkansas Department of Environmental Quality and the Arkansas Water Resources Center collect data on Beaver and in its tributaries year-round. These data give us concern that the phosphorus load to Beaver is gradually increasing over time. To continue to enjoy the high quality water we currently have, we, the Northwest Arkansas community, will have to maintain and even increase our efforts over time.”
During Secchi Day, sampling teams take Secchi disk readings to determine water clarity, and collect water samples which are tested for chlorophyll a, total phosphorus, and nitrate, to determine algal density and nutrient concentration. Secchi depth is a measure of water transparency that involves lowering a black and white disk into the water and recording the maximum depth in which the black and white pattern can be distinguished from above the water’s surface.
To read this year’s detailed Secchi report, link to BWD’s website at bwdh2o.org. Next year’s event will be held on Aug. 19, 2017. Secchi Day on Beaver Lake is made possible by 12 partners including BWD, the U.S. Army Corps of Engineers-Beaver Lake, the U.S. Geological Survey, the University of Arkansas Cooperative Extension Service, Hobbs State Park, Northwest Arkansas Master Naturalists, the Association for Beaver Lake Environment, Beaver Watershed Alliance, Arkansas Game & Fish Commission, Ozarks Water Watch, One Community, and Girl Scouts Diamonds of Arkansas, Oklahoma and Texas. Secchi Day is one of the premiere water public awareness and education events in Arkansas.
About Beaver Water District
BWD’s board meets monthly on the third Thursday. The board consists of three members from Washington County and three from Benton County. They are elected to six-year terms and every two years, a position comes open in each county. The board oversees BWD, which cleans and purifies drinking water sold at the wholesale price of $1.31 per 1000 gallons to Fayetteville, Springdale, Rogers and Bentonville. The raw water is sourced from Beaver Lake, which one in seven Arkansans relies on lake for safe, clean drinking water. BWD’s mission is to serve our customers’ needs by providing high quality drinking water that meets or exceeds all regulatory requirements and is economically priced consistent with our quality standards. For more information, visit www.bwdh2o.org.