Documenting Biological Recovery in Acidified Adirondack Streams in Response to the 1990 Amendment to the Clean Air Act

Science Center Objects

BACKGROUND Chemistry data from a group of Adirondack lakes monitored since the mid-1990s indicate that chemical recovery is currently underway and can be attributed to declining deposition loads of sulfate and nitrate in direct response to the 1990 amendment to the Clean Air Act (CAA) and other regulations. Changes in the water quality of several western Adirondack streams suggest that chemical...

BACKGROUND

Chemistry data from a group of Adirondack lakes monitored since the mid-1990s indicate that chemical recovery is currently underway and can be attributed to declining deposition loads of sulfate and nitrate in direct response to the 1990 amendment to the Clean Air Act (CAA) and other regulations. Changes in the water quality of several western Adirondack streams suggest that chemical recovery from acidification is underway as well, while data from recent large-scale stream surveys also support the assertion. Changes in stream chemistry, however, appear to be more complicated than changes in lake chemistry. The pH levels in Buck Creek, for example, have changed very little since the 1990s but dissolved organic carbon (DOC) concentrations are increasing significantly. Though acidity has not changed appreciably, the increasing DOC concentrations more effectively bind inorganic monomeric aluminum (Ali) to produce organic monomeric aluminum (Alo) and large declines in Ali concentrations in streams across the region. Because Ali is biologically labile, and generally responsible for most mortality observed in resident brook trout (and other species) populations, the observed decline in Ali levels means that toxicity should have also declined greatly in many formerly acidified streams. In fact, Ali concentrations declined significantly in several western Adirondack streams between 1989-1990 and present, extremely high Ali concentrations no longer are evident in the same streams, and the duration in which highly toxic Ali concentrations persist in Buck Creek has declined markedly between toxicity-tests done in 1989-1990, 2001-2003, and 2015-2017. The substantial improvements in water quality suggest that biological recovery (increases in density and biomass of brook trout populations and other fish species, and community richness) should be occurring in streams of the western Adirondacks that were moderately to strongly acidified during the 1980s and early 1990s.

 

Fish assemblages make effective targets for assessing the impacts of, and recovery from, acidification in headwater streams of the western Adirondacks. Unlike lakes, quantitative surveys of stream-fish assemblages generally require relatively little time and effort. A crew of 5-6 people can usually survey a small stream in 2-4 hours. In addition, the New York State Department of Environmental Conservation (DEC) quantified community richness and the number (and biomass) of resident species populations (and entire communities) per unit area in 36 western Adirondack streams during 1979 and 1999, while the Adirondack Lakes Survey Corporation (ALSC) quantified fish assemblages at four streams in the same region during the 1988-1990 Episodic Response Project (ERP). Although no significant changes in stream-fish assemblages were detected between 1979 and 1999, significant decreases in Ali concentrations and in the duration of toxic conditions in several western Adirondack streams since 1990 suggest that stream-fish assemblages have recovered to some extent by now. While fish assemblages at 10 of the original study streams resurveyed during 2014-2016 suggest some recovery may be underway, no thorough statistical evaluation of biological recovery has been attempted in streams of the region. Thus, the likelihood for observing some level of fishery recovery is high for streams in the Adirondack (and Catskill) Mountains of New York State.

Very few people know how successful the 1990 amendment to the CAA has been at improving conditions in 1000s of lakes and streams across the northeastern United States. The strong chemical recovery and the limited recovery of brook trout populations in some lakes and streams in New York State and other regions needs to be widely circulated, yet little effort (funds/time) has been allocated at the State and federal levels to document and publicize this important recovery. This type of information needs to be disseminated as rapidly and widely as possible to show the value of scientific information and how national regulations that limit atmospheric emissions of sulfur dioxide (SO2) and nitrous oxides (NOx) have affected (or will affect) stream biota in the past, present, and future. Such efforts are important because they provide a basis for informed management/regulatory decisions needed to best protect natural ecosystems and regional economies. Although data analyses and reporting will be part of a separate request, the collection, analysis, and dissemination of observed responses (biological recovery of acidified streams in New York State) due to clearly documented declines in acid deposition is currently not available, but crucial to advertise tangible successes of the 1990 amendment of the CAA.

OBJECTIVES

The primary objective of this study is to gather information needed to assess the effects of the 1990 amendment to the CAA on chemical and biological recovery of previously acidified streams in the Adirondack Mountain region of northern New York State.

APPROACH

The USGS plans to conduct quantitative fish surveys in 36-42 headwater streams (that were surveyed previously), compile the original chemistry records and fish data from the 1979 and 1999 (and 1988-1990) surveys, and compile contemporary (2020-2021) fish species population and community data needed to conduct a future analysis of changes in acid-base chemistry and fish assemblages which hypothetically occurred between the three survey periods. The USGS will conduct discharge measurements, collect discharge records (from sites with the USGS discharge stations), collect and analyze chemistry samples and survey fish assemblages at 36-42 study streams once during summer 2020, or 2020 and 2021 to document the current status of fish assemblages and provide a locus and gauge any chemical and biological recovery which may have occurred since previous (1979 and 1999) fish-surveys. Contemporary discharge measurements will be verified and added to miscellaneous flow records in the National Water Information System (NWIS) web site; while chemistry samples shall be analyzed for routine acid-base constituents, validated, and placed into NWIS as well. Contemporary (2020-2021) fish-capture records will be validated then published as a publicly available USGS Data Release. Historic fish-capture records from the 1979, 1990, and 1988-1990 surveys will be obtained, converted to pdf file formats (for archival purposes), and transferred onto electronic spreadsheets for future analysis.

Project Location by County

Adirondack Region: Clinton County, NY, Essex County, NY, Franklin County, NY, Fulton County, NY, Hamilton County, NY, Herkimer County, NY , Lewis County, NY, Oneida County, NY, Saint Lawrence County, NY, Saratoga County, NY, Warren County, NY, Washington County, NY