Threats to Water Quality
Nearly 80% of MountainTrue’s service area is forested, and much of that is protected by state and federal public lands, which directly helps the water we drink to stay clean. Many of the headwaters of the Broad, Green, French Broad, Hiwassee, and Watauga Rivers are located in such forests; therefore, these rivers are broadly pristine and unpolluted at their sources.
Forests provide shade to cool streams, filter stormwater, remove pollutants, sequester carbon, and reduce erosion and sedimentation by holding soil in place. Trees also contribute to the in-stream habitat for several species, including caddisflies, mayflies, and stoneflies, a critical pillar for our region’s trout industry. These aquatic insects are used as bioindicators to assess a stream’s health.
As these rivers wind through more developed and populated areas, they become increasingly impacted by sediment from poorly managed construction sites, bacteria, and fertilizer from farms lacking livestock fencing or streamside buffers, sewage overflows from aging and inadequate wastewater infrastructure or failing septic systems, and a myriad of other human practices. Here are some of the most prominent threats to our region’s surface waters.
Poor Agricultural Practices
We love our farmers. They grow the food that sustains us, and their work is critical to ensuring the future food security of our region. Most farmers recognize the quality of their land is intrinsically bound to the quality of the water they use to irrigate their crops or feed their cattle.
However, poor agricultural management practices can spoil the water for downstream neighbors. If farmers don’t fence their cows out of creeks, their hooves cause severe instability and erosion of streambanks. Left to roam free, these cows also defecate in and near tributaries, allowing bacteria, parasites, and other pathogens to enter our waterways. It’s not just troublesome livestock operations; farmers who plant crops to the water’s edge and fail to maintain adequate riparian buffers are also at fault.
Removing the riparian buffer from a stream is like removing a load-bearing wall in a house. Without the support of vegetation's root masses, a bank is shaky ground and at the mercy of the river flowing next to it. The result is severe bank erosion and more stormwater runoff that carries bacteria and other pathogens, sediment, pesticides, and nitrogen-rich fertilizers into our waterways.
Agriculture is also a major source of excess nitrogen and phosphorus in streams, often referred to as nutrient pollution. Sources of nutrient pollution often include agricultural fertilizers, livestock waste, stormwater runoff, aquaculture, and municipal sewage. Nitrogen and phosphorus are naturally occurring in the environment and are essential for nutrient cycling and ecosystem function.
However, they can cause negative impacts on water quality when entering streams and rivers in excessive amounts. Too much nitrogen and/or phosphorus in an aquatic environment can lead to the eutrophication of waters or excessive growth of plants which lowers the amount of dissolved oxygen available to aquatic life and can ultimately lead to fish kills. Excess nutrients in water bodies can also lead to algae blooms, some of which can release toxins and affect human and animal health. Increased algae growth can impact the water quality, creating costly problems for tourism, recreation, property values, and drinking water treatment.
Failing Sewer, Wastewater, and Septic Systems
Our region’s stormwater and sewer infrastructure, septic systems, and wastewater treatment plants were built for smaller populations and haven’t been updated in tandem with population growth or increased rainfall due to climate change. These stressors, especially when added together, can lead to sanitary sewer overflows and combined sewer overflows. Wastewater treatment plants with inadequate carrying capacity more frequently overflow untreated sewage into area surface water. Heavier and more frequent rain storms cause stormwater to enter into and then spill from leaking sewer pipes — causing polluted waters to gush from utility holes and enter storm drains that lead into rivers and streams. And property owners who are unconnected to sewer lines can experience septic system failures that contaminate surface waters, groundwater, and nearby wells. Our water team monitors for these types of infrastructure failures by monitoring the water’s nutrient levels and testing for E. coli, a form of bacteria pollution-associated sewage leaks.
Poorly Managed Development and Sprawl
According to projections by North Carolina’s Office of State Budget and Management and Georgia’s Office of Planning and Budget, our region's population will grow by more than 200,000 people, or 15.65%, between 2020 and 2050. How we accommodate our new neighbors will have dramatic effects on water quality.
Historically, local governments have largely been resistant to land-use planning and regulation, which has led to sprawl — the process in which the spread of development across the landscape far outpaces population growth. This low-density development devours our open spaces, farmlands, and forests. It leads to fewer trees, more construction, and more impervious surfaces like parking lots, roads, buildings, and other structures. Stormwater glides off hard surfaces and poorly managed construction sites, mixing with sediment, nearby litter, and other pollutants before flowing into local waterways.
Additionally, expanding our road infrastructure to serve sprawling development increases the road demand that needs salting during winter storms. Salting is costly, at $15 per mile, and increases the demand for road repairs. Generally, we already oversalt for storm events, and increases in these salts are measured by our Water Team by observing the conductivity levels in streams. Spikes in conductivity, or the amount of dissolved ions in the water, can indicate increases in salinity, or salt in the water. Increases of salts in aquatic systems can happen due to road salting, but other sources of pollution include wastewater discharge, agricultural, and impervious surface runoff. Periods of increased conductivity indicate pollution in the water, and can be deadly to aquatic life. Fish and other aquatic animals can be harmed by salts in the water, because it causes stress on the functioning of basic physiological processes. In addition to salts disrupting a fish's ability to osmoregulate, high conductivity can reduce the amount of dissolved oxygen in the water, causing additional challenges for survival (like breathing!). Salts also cause damage to riparian plants, essential to the health of freshwaters, and can be fatal to some of our most sensitive aquatic animals like salamanders, fish, and freshwater mussels. Conductivity is one of the many water quality parameters used to calculate the watershed “grade” in the Stream Health Analysis sections of this report.
Our Changing Mountain Climate
Climate change — the ongoing increase in global average temperatures — will have profound effects on our region. According to the 2020 North Carolina Climate Science Report, the mountains of western North Carolina are expected to experience higher air temperatures resulting in warmer nights, hotter days, and less snowfall. This area will also likely experience more rainfall and an increase in the number of days with extreme precipitation.
An increase in rainfall and more frequent and heavier storms will exacerbate some of the threats described above. More rain will result in more stormwater runoff, flushing pollutants from impervious surfaces and poorly managed farms into our waterways. Heavier, more frequent storms and flooding will overwhelm faulty septic systems and our already inadequate municipal wastewater and sewer systems. Hotter weather creates a more hospitable environment for many invasive plant and animal species and will make protecting our natural heritage and our outdoor economy more difficult and costly.
Ironically, the fact that the mountains of Southern Appalachia are expected to experience less severe climate effects than other regions of the United States, especially areas closer to sea level and around the Gulf Coast, could supercharge migration and development in our region beyond current projections. This growth could strain our already under-built infrastructure systems and make protecting our forests and the health of our waters far more challenging.