As the temperatures cool, the likelihood of algae blooms and associated water quality problems diminishes. Flowing through the sparsely populated northeast North Carolina, the Chowan River needs a break from being plagued by several blooms that raised health alerts from the State this summer.
The World Health Organization (WHO) provides guidance on the probability of adverse health effects due to cyanobacteria exposure. WHO cautions that moderate probability of adverse health effects with 100,000 cyanobacterial cells/ml. The prolonged bloom in the Chowan had cell counts 15 times that amount!
Clearly nutrient related water quality problems exist in the river. The severity of this bloom has put the river on the NC DEQ’s radar and the state will need to undertake pollution control protection for this sickened ecosystem.
North Carolina is no stranger to algal blooms. Hot summers, runoff from agricultural and urban lands combine with shallow, slow moving estuaries create conditions that cause harmful algal blooms (HABs). While common in our State, its becoming more common in areas to our north. Minnesota, Lake Michigan, and the Chesapeake Bay are all experienced in dealing with HABs.
A story from New Jersey illustrates how warmer summers are helping fuel the occurrence of HABs in areas to our north. Lake Hopatcong, New Jersey’s largest freshwater Lake and a popular summertime retreat experienced a severe bloom prompting the State’s Department of Environmental Protection (DEP) to shut down the Lake for recreational use around the July 4th Holiday. Their press release read:
“DEP is recommending that local health authorities close all public swimming beaches along the lake due to the widespread nature of the bloom…avoid all contact with water from Lake Hopatcong until further notice. People also should not eat fish caught in the lake or allow pets to come in contact with lake water or drink the water.”
This is certainly what no State wants to have happen to their recreational waters. Indeed, North Carolina is in the final steps of a years long process to shore up its nutrient strategies to reduce the occurrences of HABs. These efforts are desperately needed to curb a problem which is becoming more pervasive.
In 1999, the largest coastal restoration project in NC began with funding from the State’s Clean Water Management Program to purchase nearly 2000 acres of farm land in Carteret County for the purpose of restoring wetlands that were drained to become North River Farms. After 11 phases of restoration over 20 years, the State’s largest coastal restoration project is entering a new phase where we get to monitor and maintain what’s been done.
The N.C. Coastal Federation has overseen the work to return farmland back to forested, freshwater and tidal wetlands and the project has expanded to 6000 acres. With the restoration activities wrapping up, the Federation envisions being able to provide tours to showcase this re-imagined landscape.
Benefits of the project include increased habitat to support species diversity, improved water quality, groundwater recharge, and supporting shellfish populations and increased opportunities for shellfishing. As one of the premier restoration projects in the country, a visit to the site would be worthwhile.
Skimming – A recent story on the Corps of Engineers use of algal skimmers in Florida to help combat toxic algal blooms reminded me of North Carolina’s own efforts to combat algal blooms. In Florida, the Lake Okeechobee skimming process uses “dissolved air flotation” to bring algae to the surface and remove it from the water column. The process has been used effectively in wastewater treatment where the systems are contained better able to engineer but it is a relatively new approach to combating harmful algal blooms in the natural environment.
Scrubbing – A slightly different “in-line” removal process was tried in North Carolina to use scrubbing of algae. Durham partnered with HydroMentia to test the effectiveness of algae scrubbing on Falls Lake waters. In the pilot study, HydroMentia found the method had a positive effect at removing nitrogen and phosphorus, the fuel driving algal blooms (See their report https://hydromentia.com/falls-lake-algal-turf-scrubber-pilot-final-report/). While technologies such as these may not be cheap, they may be part of the solution to the nutrient pollution challenges facing NC.
The Falls Lake Nutrient Strategy put in place by NC DEQ in 2010 provides more than just drinking water protections for Falls Lake. Communities in the Falls watershed such as Durham benefit from the rule protections, too. Durham’s drinking water supply comes from Lake Michie and Little River Reservoir, both located in the Falls Watershed. This spring, local news reported that algae blooms in these waterbodies are fowling the taste and smell of water for city residents. A cause of these algae blooms is excess nutrients in the water body combined with warming temperatures.
The rules put in place to protect Falls Lake also benefit upstream water quality. They address lowering nutrient pollution from sewage treatment plants, reducing polluted runoff from new development and farms while protecting streamside forests. While implemented for Falls Lake, upstream lakes like Michie and Little River also benefit from these protections.
Due to a legislative mandate, the State Division of Water Resources is currently revising all its nutrient strategy rules. In doing so, it’s important to realize that, while the rules target a lake or estuary, they benefit communities throughout the watershed.
A necessary step in the environmental mitigation process is to secure long-term stewardship of the project site. Among the responsibilities of the steward is to visit and inspect mitigation sites to make sure that the terms of the easement are being honored. For the Neville Farms site, the stewardship responsibility of the site was arranged with Unique Places to Save (UP2S). UP2S has a strong presence in the area near the farm, has worked on similar projects, and looks to foster relationships with landowners to develop shared goals. All these reasons made them a good fit for working with us.
The City of Raleigh got some good new. As reported on WRAL, the Army Corps approved the City’s request to reallocate Falls lake’s storage toward drinking water allowing the City to increase the drinking water withdrawals by 22 million gallons a day. As we’ve covered previously, aside from drinking water, Falls Lake has several allocated uses that include flood control and sustaining ecological functions. With this change, lake managers will look to preserve more water in the lake to supply drinking water for Raleigh.
Why is this good news for the City? Raleigh has struggled to identify long-term water sources to provide for its growing population and even explored creating a new reservoir. With this move, Raleigh’s water supply is more secure for the foreseeable future. It also raises the importance of upstream watershed protection. If Raleigh is going to be counting more on Falls Lake, the City, State and region should be stepping up efforts to prevent its pollution and protect its long-term health.
A US Geological Survey Report released late in 2018 provides a needed review of water quality trends for select NC rivers and streams over the last 25-years (1989-2013). Importantly, the report focuses on the quality of water flowing to drinking water reservoirs in North Carolina. Here, I’ll briefly cover the results affecting Jordan Lake where data both in streams and the Lake were analyzed to gauge what’s happening and what’s needed to protect our drinking waters.
Over the 25-year study period, population in counties surrounding the Lake grew by 85%. Not surprisingly, during that period developed land use nearly doubled in watersheds draining to Jordan Lake, typically coming from less polluting forested land use. Also, during that time, improvements have been made to waste water treatment plants that have reduced the discharge of pollutants even though the plants were serving more users. Overall, there are a mixture of factors that have influenced water quality flowing to Jordan Lake.
What are the trends?
In a word, mixed. Generally, monitoring of nutrients in streams near Jordan Lake showed improvement TP concentrations more than TN (See Figure 1). Conditions in Jordan Lake, however, were less promising with stations showing increased concentrations for both TN and TP. Much like our estuaries, organic nitrogen was the primary form of N that increased during the period of study.
Increases in triangle-area population continue to put a strain on Jordan Lake both for adequate quantity and quality for its users. Even though management efforts over the study period resulted in some in-stream water quality improvement, conditions continue to be poor at the lake demonstrating the continued need for policies protective of the Lake.
The Chesapeake Bay has experienced problems similar to those in NC’s estuaries as it relates to nutrient pollution. Low-oxygen “dead zones’ have resulted in persistent fish kills and stressed or diminished aquatic ecosystems.
Area draining to the Bay stretches from from New York to Virginia and has had federally coordinated efforts to curb nutrient pollution since the 1980’s. These efforts combined with funding to improve wastewater treatment and improved development and agricultural practices have all played a role in improving water quality in the Chesapeake though not as much as bay managers would like.
The news this year is mixed.
Good News: In spite of a predicted larger than average dead zone “due to higher spring flows and nitrogen loading from the Susquehanna and Potomac rivers”, hypoxia (i.e. low oxygen) in the Bay for the month of July was historically good.
Bad News: Overall, summer hypoxia was average with late summer conditions worse than average.
What’s this mean? The challenge of reducing nutrient pollution and its associated water quality problems is formidable. As covered previously, sustained effort, political will, and funding are needed to make a positive impact. Even then, increased population, loss of wetlands and forest, and the misuse of nutrients can overwhelm these efforts, neutralizing progress. NC is in the process of re-adopting its nutrient rules. In doing so, it should look for opportunities to eliminate pollution loopholes and find ways to strengthen the overall effectiveness of its nutrient reduction strategies.