Is There Blue Green Algae in the Shenandoah River

Carpets of grass-colored algae have long plagued the Shenandoah River in Virginia, making it unpleasant to be on the water during some of the hottest weeks of the year. And, the problem is getting worse. This summer, the state alleged that an expansive algal bloom impacting more than 52.5 miles of the river's Northward Fork was not only unsightly and foul-smelling but also toxic to humans, pets and wildlife.

The public health advisory was lifted in mid-September, nearly eight weeks subsequently it was issued.

For Shenandoah advocates, the blooms — both those that are a nuisance and those that could harm users of the river — are a glaring reminder that more piece of work is needed to clean upward agricultural pollution in the region.

Algal blooms occur in the Chesapeake Bay, too as streams, rivers and lakes throughout the Bay region. They generally point an ecosystem out of balance. Some factors fuel them, particularly in slow-flowing or shallow waterways. Among the culprits: Nutrient pollution from fertilizers and sewage, also as increasing bug from climatic change, such as extreme wet and dry spells and warmer water temperatures.

In the Shenandoah River basin, drought conditions this summer set the stage for a bloom that began to grow in July. Since mid-June, the N Fork of the Shenandoah — already a shallow waterway compared with others of its size — was below its 96-year average depth, according to a river gauge at Strasburg.

Shenandoah Riverkeeper Mark Frondorf said this twelvemonth'southward crop of algae was a particularly bad version of the ones he'd seen in previous years and reported it to country authorities. Frondorf and the Potomac Riverkeeper Network have submitted dozens of complaints about algae blooms on the Shenandoah over the past decade.

An algal mat hugs the surface of the North Fork of the Shendandoah River near Lower River Road in Tom's Brook, VA, on July 28. (Linda Allen/Courtesy of Friends of the North Fork)

"On the North Fork, you get these big thick algal blankets, and they smell," Frondorf said of the blossom that developed in July and August. "A lot of people think there'due south been a sewer pipe that'southward ruptured. It'southward such an awful, foul smell."

The Virginia Section of Health regularly tests along certain public saltwater beaches for the presence of harmful algae blooms equally well equally bacteria that make swimming dangerous. Merely testing in freshwater rivers is inconsistent and typically in response to a complaint.

After finding cyanobacteria in the Shenandoah's algae in mid-July, the county and then country health authorities issued advisories warning people to avert the river. This less common blazon of blue-green algae releases toxins that, when touched or ingested, tin can cause rashes and gastrointestinal illness, and it tin can be fatal to dogs and other animals.

Boosted testing in early August caused the state Department of Health to expand its advisory to encompass a full of 52.v miles of the Shenandoah's North Fork, a winding just shallow department of the river that laces through the country's Seven Bends State Park in Woodstock.

Blooming numbers

Harmful algal blooms aren't new. But the trouble has spread as freshwater blooms increased significantly over the past forty years, making them an ecology problem in all 50 states. In the Bay region, a 2015 study found that harmful blooms were occurring more than ofttimes than they had xx years before. Blooms beyond the country have been the subject of nearly 400 news reports so far this year, according to the nonprofit Environmental Working Group, which has tracked a ascension in such reports over the concluding decade.

In belatedly August, harmful algae blooms were also proliferating across Hampton Roads near the Chesapeake Bay Span Tunnel in Virginia. Aerial photos taken past the Chesapeake Bay Foundation later on an open-water swimmer reported them showed reddish-brown blooms streaking waters about the oral cavity of the Bay and in the Lafayette and York rivers.

A harmful red-brownish algae bloom appeared nigh the Chesapeake Bay Bridge Tunnel on Aug. 26, 2021. (Chesapeake Bay Foundation and American Multimedia Solutions)

In Maryland, the Frederick County Health Department told residents to stay out of the water at Cunningham Falls Country Park simply before Labor Day weekend due to toxic algae blooms.

Though this summer was the first fourth dimension a section of the Shenandoah River was under a recreation informational for a bloom of cyanobacteria, the river has a long history of being burdened past other types of algae.

The Shenandoah Riverkeeper and Potomac Riverkeeper Network sued the U.Southward. Environmental Protection Agency in 2017 over excessive algae, which had caused fish kills and was regularly rendering the river unusable. They asked the courts to compel the EPA and Virginian to declare the Shenandoah River impaired past nuisance filamentous algae.

Inclusion on the state's dumb waters listing would let the Virginia Department of Environmental Quality to develop specific plans to reduce pollution from the surrounding landscape, much of it farmland. The courts, though, ruled that the DEQ left the river off the listing for good reason, pointing out that Virginia did not have a h2o quality standard for algae that could trigger such a list. The decision stood despite an appeal that wrapped up in 2020.

Since so, the DEQ has been working on the outcome anyway, under pressure from ecology groups that have been tracking algal blooms on the Shenandoah for more than a decade. The bureau adamant that it could develop a standard for measuring algae that would, over the class of a few years, help to decide whether a waterway is impaired by the amount of algae occurring.

This would be like to a chlorophyll a standard that was adult for the James River a few years ago. The James is currently the simply Bay tributary with a specific numerical limit for chlorophyll aimed at reducing algae.

Measuring chlorophyll in water is a surrogate for directly measuring algae biomass, a process that is far more expensive and fourth dimension consuming. Chlorophyll is the pigment that allows plants, including algae, to convert sunlight into compounds through photosynthesis. Chlorophyll a is the predominant type in algae.

DEQ spokeswoman Ann Regn said the criteria beingness considered would help protect recreational users in portions of the Shenandoah River'due south North Fork, South Fork and mainstem from nuisance filamentous green algae.

The agency does not at this time plan to prefer criteria to address blooms caused by cyanobacteria, like the one that occurred this summer.

"Filamentous light-green algae have been the focus of concern in the Shenandoah in recent years considering big occurrences of blue-green alga [in] mats or in the water column take non previously been observed by DEQ," Regn wrote in an email.

Contributing factors

Runoff from agriculture operations often contains nitrogen and phosphorus — nutrients derived from manure and fertilizer — which are the primary cause of algae blooms and other water quality woes in the Bay and many of its rivers.

Advocates have long pegged runoff from livestock and poultry operations as a major correspondent to the overgrowth of algae in the Shenandoah River. Cattle that have admission to the river tin can defecate in it. And manure from large poultry operations, which is often spread on nearby fields as fertilizer, also contributes to the river'due south algae issues.

Algae collects on the North Fork of the Shenandoah River near Bethel Road in Strasburg, VA, on July 22. (Courtesy of Friends of the North Fork)

A 2017 report from the Ecology Integrity Project found that fields in the counties around the Shenandoah River received at least one and a one-half times more phosphorous than the corporeality needed by the crops harvested in those counties, which allows backlog nutrients to run off into local waters.

"Nosotros have huge inputs of nutrients into the river that fuel both types of algal blooms," said Phillip Musegaas, vice president of programs and litigation for the Potomac Riverkeeper Network. Meanwhile, "climate alter is changing the river. Nosotros volition see more blooms because of hotter summers and longer periods of low water."

Frondorf, the Shenandoah Riverkeeper, said progress has been fabricated on many of the farms that abut the river. The number of cattle herds with direct access to the river has gone down from 75 to about 15 since 2015, he said.

In 2020, the Virginia general associates passed a bill that will require cattle operations with 20 or more bovines in their pastures to exclude the animals from streams with fencing starting in 2026. Only the mensurate has several caveats related to whether the country meets its Chesapeake Bay pollution reduction goals in 2025 and whether there is adequate funding provided to help farmers install the fences.

"Algal blooms are hard to predict, sort of like the weather, but we know that nutrients e'er exacerbate the upshot," said Joe Woods, Virginia senior scientist for the Chesapeake Bay Foundation. "If we invest more in cleaning up nutrients to the Shenandoah River, the river will be ameliorate and so will the Bay."

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Source: https://www.bayjournal.com/news/pollution/shenandoah-river-s-algae-woes-worsen/article_982fd1e0-11a9-11ec-8dda-37fd3ab41f01.html

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