By Noa Meiri and Adriana Kirk
Noa Meiri graduated from UNC-Chapel Hill in 2022 with a B.S. in Environmental Sciences and a minor in Chemistry. Over the course of her undergraduate career, Noa engaged in multiple field ecology studies at the Highlands Biological Station. Noa is currently a Research Assistant with the UNC Institute for the Environment.
Adriana Kirk is a sophomore at UNC-Chapel Hill majoring in Environmental Sciences with minors in Biology and Music. She is working as an Environmental Policy intern with the North Carolina Collaboratory during the 2023 spring semester.
Editor’s Note: Topics discussed in this blog post along with other research being conducted as part of the UNC Falls Lake Study will be examined in depth at a free public symposium on April 19, 2023. Registration for the event can be found here: https://nutrients.web.unc.edu/2023-falls-lake-research-symposium//
Falls Lake: A Valuable Resource
Falls Lake — a reservoir built in 1981 by the Army Corps of Engineers — provides potable drinking water to over half a million people in North Carolina’s piedmont, serving residents of Orange, Person, Durham, Granville, Wake, and Franklin counties. Falls Lake also safeguards against flooding and droughts, provides habitat for wildlife, and serves as recreation for visitors. However, shortly after it was impounded, the lake was determined to be nutrient sensitive waters, meaning it was susceptible to harmful algal blooms from excess phosphorus and nitrogen.
These nutrients enter Falls Lake through agricultural runoff, wastewater treatment plants, sewers and septic systems, urban runoff, erosion, and atmospheric deposition.
To target excess nutrient inputs, the Falls Lake Nutrient Management Strategy was enacted by the state’s Environmental Management Commission in 2011. The Falls Lake Rules, as they are commonly known, address nutrient loading from point and nonpoint sources under three main guiding principles: to return the current nutrient levels back to the 2006-2012 baseline, to protect the lake’s use as a drinking water source, and to maintain and enhance current practices by local governments that ensure water quality.
Harnessing the Power of Research
In 2016, the NC General Assembly directed UNC-Chapel Hill and the NC Collaboratory to evaluate water quality and identify solutions for nutrient management strategies for Falls Lake and Jordan Lake, another important Piedmont reservoir.
The multi-year study is being led by Mike Piehler, the Director of the UNC Institute for the Environment, and includes researchers from NC State and East Carolina. The study is designed to take a comprehensive approach to assessing and improving water quality in Falls Lake and includes several research components, including:
- evaluating water flow and circulation through monitoring efforts;
- analyzing the levels of algal growth in the lake in changing conditions and the potential for toxic algae to develop;
- tracking nutrient loading from wastewater systems and streambank erosion;
- discussions with stakeholders throughout the watershed;
- developing the policy and finance solutions to implement management actions.
Over the course of the study, researchers have been working closely with the Upper Neuse River Basin Association and the NC Department of Environmental Quality to share data, provide updated findings, and partner in efforts to improve the water quality in Falls Lake.
Land Conservation Promotes Multiple Ecosystem Benefits
One aspect of the study we have been working on involves understanding the significance of land conservation in watershed management as a tool to reduce nutrient loading. Research shows that when forest cover drops below 70%, there are measurable negative impacts on a watershed’s water quality. With 36% of the Triangle predicted to be covered in impervious surfaces (such as concrete and asphalt) and 60% of the watershed forested, promoting land conservation and maintaining forested areas near waterways provides numerous benefits to watersheds.
To name a few, the presence of conserved land near water bodies reduces flooding, improves animal migration routes, sequesters carbon, reduces streambank erosion, and minimizes algal growth by shading streams. Most relevantly to Falls Lake, land conservation can be instrumental in reducing nutrient loading and eutrophication in watersheds through direct and indirect means.
Forested land surrounding watersheds act as a filter for runoff. Water flows through the soil gradually, where sediment and pollutants are sifted out and water is purified by plants before entering streams or rivers. Studies have found 30 to 98% reductions in nitrogen, phosphorus, sediments, pesticides, and other pollutants in surface and groundwater after passing through forested land. However, when land is developed and impervious surface cover increases, these natural benefits diminish. Thus, conservation safeguards land that would otherwise be developed and ensures that forests’ ecosystem services are maintained.
Conservation Activities in the Falls Lake Watershed
Land conservation has long been a priority to protect drinking water in the Falls Lake watershed. In 2006, the Upper Neuse Clean Water Initiative (UNCWI) was founded. The Initiative is a partnership between conservation organizations, local and state governments, and landowners within the Upper Neuse River Basin to protect Falls Lake and other vulnerable waterbodies through conservation. UNCWI has been successful in its mission—between its inception in 2006 and 2015, the Initiative has protected 88 properties stretching along 84 miles of stream banks across 7,926 acres, reducing nitrogen and phosphorus inputs by thousands of pounds per year.
The value of land conservation is recognized as a key watershed management strategy in other areas of the country. For example, land conservation has also been a longtime component of the Chesapeake Bay’s nutrient management strategy. The Chesapeake Bay Program – a partnership between federal agencies, state agencies, local governments, academic institutions, and non-governmental organizations – parallels UNCWI in the Falls Lake watershed.
The Program has committed to protecting 30% of the total Chesapeake watershed by 2030 and is currently on track in achieving its conservation goals. Currently, 9.2 million acres of land in the Chesapeake Bay watershed are protected. The Partnership’s success can be attributed to the efforts and development of the Chesapeake Bay Land Change Model (CBLCM), which helps predict future urbanization scenarios and guides government and stakeholder action.
Innovative policy and efforts surrounding land conservation in other watersheds, such as in the Chesapeake Bay, can be a helpful point of reference as we develop and implement new strategies to improve water quality in the Falls Lake watershed.
Falls Lake Study Public Symposium
The issue of land conservation and other research topics will be discussed at the Falls Lake annual symposium on April 19, 2023. Attended by researchers and stakeholders across North Carolina, the symposium provides a forum to showcase and discuss the progress and results of the research. The symposium encourages an open dialogue and feedback on the advancement of the study.
The symposium comes at a critical time in the study as the research team will be submitting its final results and recommendations to the North Carolina General Assembly in December of 2023.
For more information about the UNC Falls Lake study visit: https://nutrients.web.unc.edu/