January 6, 2015
Friends of the Smokies has already contributed more than $600,000 to support water quality monitoring in Great Smoky Mountains National Park, with another $85,000 for the monitoring program on the park’s Needs List for 2015. But is it really worth all that money to study water?
Read the full report below from Matt Kulp, the park’s Supervisory Fishery Biologist, to learn just how important water quality is to the total health of America’s most-visited national park and the whole Southern Appalachian region.
by Matt Kulp, Supervisory Fishery Biologist, GSMNP
What Is the Issue? When you think about it, water is one resource that effects every living and non-living organism within our parks ecosystem. Whether it’s the rain that falls on the forests and eventually makes its way to the soils and streams, or simply falls on a historic structure or your car while visiting, water and water quality can impact all of these things in both the long and short term. The acid rain (pH 4.0-5.0) and acid fog (pH 2.0-4.0) not only fade our car exteriors and damage buildings over time, the low pH waters also stress forests, soils, streams and the plants and animals that live in each of these environments. In fact, acid stress has eliminated 6 headwater brook trout populations in the last 30 years and has also stressed high elevation forests to the point that they are much more susceptible to exotic insects and diseases. Stream acidification is primarily caused by air-borne acid pollutants generated from coal-burning power plants and vehicular traffic. In 2006, the Tennessee Department of Environment and Conservation (TDEC) designated twelve streams in Great Smoky Mountains National Park (GRSM) as “impaired” (303(d) listed) based on monitored stream chemistry pH that is too low to sustain healthy aquatic life. If nothing is done, stream conditions will continue to worsen. Scientists estimate that if pollution levels remain the same, in 30 years all streams above 1800 feet elevation will experience declines in pH to below 6.0, and by the year 2068 nearly all of the park’s streams will have a pH of 5.0 or less (100 times more acidic than neutral water).
What Are We Doing? Concerned about the effects of acid deposition on water quality and aquatic and terrestrial flora and fauna, resource managers initiated a long-term water quality monitoring program in 1993. The monitoring program focuses on answering two key water quality issues: 1) are water quality trends getting better or worse, and 2) how do air emission changes from power plants and cars affect not only water quality, but soil chemistry and the severity of storm events on stream water over time. In order to answer these questions, a suite of 43 sites from high to low elevations are monitored in key watersheds on a bi-monthly basis. Key tests used to assess water health include stream pH (acid levels), sulfate (main source fossil fuels), nitrate (main source automobile emissions) and metals (such as aluminum, which is toxic to animals). Additionally, continuous precipitation, throughfall, soil water chemistry, stream water chemistry and stream flow data is collected from Noland Divide watershed year round by University of Tennessee staff to look at both base and storm flow impacts on high elevation ecosystems. Some bi-monthly samples are collected by staff from the University of Tennessee; however most of the samples are collected by Park volunteers from groups like Trout Unlimited, FOTS and other park VIP’s. Annually, these volunteers provide 800-1,000 hours of volunteer service and hike 0.25-13 miles per trip to collect the samples.
What Have We Learned? Results from water quality sampling indicate mixed results in high and low elevation streams. In many high elevation streams, soils and forests continue to suffer from more than 100 years of pollution being deposited upon them. In 2013, roughly 11% of the samples collected are at a pH<6.0, a critical threshold for aquatic life. Toxic levels of aluminum were found in 5% of samples indicating aluminum is still leaching from high elevation soils due to their abnormally low pH. Although there has been a downward trend in nitrate and sulfate deposition from the air since 1998, stream sulfate and nitrate concentrations in stream water has remained constant in high elevation areas (>3,500 feet) like Noland Divide. Of additional concern, when storms occur in these high elevation forests, stream pH drops an additional 1.0-2.0 units, which is 100-1,000 times more acidic than normal levels. One positive note is that the pH decline caused during storm events is not getting larger in high elevation streams. In mid to low elevation streams (<3,500 feet), stream pH has shown 0.15-0.28 annual improvements since 2003. These data suggest emission controls are helping the lower elevation soils buffer acid inputs before they reach the stream resulting in improving stream pH values. Unlike high elevation areas, low elevation soil layers are thicker, forests have longer growing seasons and the soil have not been depleted of positive ions such as calcium, sodium and potassium which help buffer acid inputs.
What Do We Need to Do to Speed Up Recovery? What air regulators need are air emission reduction goals or “targets” so they know how to set emission policies. To get these targets, GRSM is working with researchers at Syracuse University to estimate how much air pollution would need to be reduced over time to restore park streams to a healthy condition. This level (called the “critical load”), describes the amount of sulfur and nitrogen pollution that will allow park streams to recover to ≥ pH 6.0 at various future years. The monitoring data provided by GRSM has proven invaluable in this effort as it provides the data necessary to accurately define these long term targets.
Prognosis for Recovery: These data suggest that stream pH improvement is possible, but the question is how long will it take in these high elevation areas? For some streams, recovery to a pH of 6.0 may take another 35 years. For other high elevation streams, a pH value of 6.0 could not be reached by 2050 even if air emissions were reduced to zero. One reason for the delayed improvement is that soils act like a sponge and are slowly releasing stored sulfate into streams. Studies have shown that there is a possibility for rapid release of stored sulfate if acid deposition conditions drop too rapidly. The soils are like a sponge storing sulfate that would start releasing stored sulfate at higher levels (like the sponge was being squeezed) if the amount of sulfate in the atmosphere decreases too rapidly. This is a key finding indicates air regulators must ensure air pollution reductions do not exceed these critical rates so that we do not “flush” the sulfates too fast, further damaging streams.
The Importance of GRSM Water Quality Monitoring: The water quality monitoring program within GRSM is vital to the long term health of not only the park, but also the southern Appalachian region. Data from this program is being used to shape national air policies, automobile emission standards and also provide feedback to regulators who set air and water quality standards to protect public health and natural resources like those in GRSM. In addition, it is very important to continue monitoring water quality in GRSM such that air pollution reductions can be evaluated to ensure they are meeting critical load goals over time. Data from GRSM is being used by Federal and State air and water regulators to identify problem areas, develop critical loads and set interim targets and recovery goals. Also, GRSM data is being used by researchers across the country to explain how acid rain affects ecosystem health, identify human health risks and model future ecosystem recovery. Most importantly, without continued monitoring, it would be very difficult to determine of air pollution reductions and “critical loads” are working to improve ecosystem health. We thank FOTS members who support these efforts to ensure a legacy of clean water and healthy ecosystems for present and future generations.