Philip R. Kaufmann

Condition of stream ecosystems in the US: an overview of the first national assessment

Abstract The Wadeable Streams Assessment (WSA) provided the first statistically sound summary of the ecological condition of streams and small rivers in the US. Information provided in the assessment filled an important gap in meeting the requirements of the US Clean Water Act. The purpose of the WSA was to: 1) report on the ecological condition of all wadeable, perennial streams and rivers within the conterminous US, 2) describe the biological condition of these systems with direct measures of aquatic life, and 3) identify and rank the relative importance of chemical and physical stressors affecting stream and river condition. The assessment included perennial wadeable streams and rivers that accounted for 95% of the length of flowing waters in the US. The US Environmental Protection Agency, states, and tribes collected chemical, physical, and biological data at 1392 randomly selected sites. Nationally, 42% of the length of US streams was in poor condition compared to best available reference sites in their ecoregions, 25% was in fair condition, and 28% was in good condition. Results were reported for 3 major regions: Eastern Highlands, Plains and Lowlands, and West. In the West, 45% of the length of wadeable flowing waters was in good condition. In the Eastern Highlands, only 18% of the length of wadeable streams and rivers was in good condition and 52% was in poor condition. In the Plains and Lowlands, almost 30% of the length of wadeable streams and rivers was in good condition and 40% was in poor condition. The most widespread stressors observed nationally and in each of the 3 major regions were N, P, riparian disturbance, and streambed sediments. Excess nutrients and excess streambed sediments had the highest impact on biological condition; streams scoring poor for these stressors were at 2 to 3× higher risk of having poor biological condition than were streams that scored in the good range for the same stressors.

Regional estimates of acid mine drainage impact on streams in the mid-atlantic and southeastern United States

The U.S. Environmental Protection Agency conducted the National Stream Survey (NSS) to provide unbiased estimates of the numbers and distribution of acidic and low acid neutralizing capacity streams in the Mid-Atlantic and Southeastern United States. The NSS employed a probability sample of 500 stream reaches to represent a target population of 64,300 stream reaches in the study area. All NSS samples were screened for acid mine drainage (AMD) influences, and population estimates of the regional extent of AMD impacts were made. Almost 10% of the stream reaches in the Northern Appalachians subregion were acidic during spring baseflow due to AMD. In the entire NSS, an estimated 4590 km (± 1670) of streams (2% of the total NSS length) were acidic due to AMD and another 5780 km (± 2090) of streams were strongly impacted, but not acidic. In subregions of the NSS with observed mine drainage effects, roughly the same number of streams were acidic during spring baseflow due to AMD as due to acidic deposition. The population estimates of mine drainage impact made in the NSS were similar to estimates made in previous surveys that attempted to census all of the streams in coal producing areas. These results demonstrate that a statistically based stream survey is a useful tool for evaluating regional water quality.

Acidic lakes and streams in the United States : the role of acidic deposition

A statistically designed survey of lakes and streams in acid-sensitive areas of the United States, the National Surface Water Survey (NSWS), was used to identify the role of acidic deposition, relative to other factors, in causing acidic conditions in 1,181 lakes and 4,668 streams. Atmospheric deposition is the dominant source of acid anions in 75% of the acidic lakes and 47% of the acidic streams. Organic anions are dominant in one-fourth of the acidic lakes and streams; acidic mine drainage is the dominant acid source in 25% of the acidic streams. Other causes of acidic conditions are relatively unimportant on a regional scale. Nearly all the deposition-dominated acidic systems were found in six well-delineated subpopulations that represent about one-fourth of the NSWS lake population and one-third of the NSWS stream population.

Protecting sediment-sensitive aquatic species in mountain streams through the application of biologically based streambed sediment criteria

Abstract We evaluated several lines of evidence to identify bedded fine sediment levels that should protect and maintain self-sustaining populations of native, sediment-sensitive aquatic species in the western US. To identify these potential criterion values for streambed sediments ≤0.06 mm (fines) and ≤2 mm (sand and fines) diameter, we examined: 1) the range of areal % fines and areal % sand and fines values at 169 least-disturbed reference sites in our sample, 2) sediment tolerance values calculated for a selection of sediment-sensitive aquatic vertebrate and macroinvertebrate taxa for both particle size ranges, 3) quantile regression predictions of the declines in vertebrate and macroinvertebrate Indices of Biotic Integrity (IBIs) at progressively higher ambient levels of streambed sediment from synoptic survey data acquired in 557 mountain stream sampling sites in 12 western states, 4) a literature review of the effects of sand and fines on the survival of salmonid eggs to hatching, and 5) a literature review of studies that quantitatively linked macroinvertebrate response to the pertinent size ranges of streambed sediment in mountain streams. Predicted maximum vertebrate Index of Biotic Integrity (IBI) declined 4.4 points (SE  =  1.0) and macroinvertebrate IBI declined 4.0 points (SE  =  0.60) for each 10% increase in % fines. Similarly, for each 10% increase in % sand and fines, the predicted maximum vertebrate IBI decreased 3.7 points (SE  =  0.50) and macroinvertebrate IBI decreased 3.0 points (SE  =  0.50). Combining all lines of evidence, we concluded that for sediment-sensitive aquatic vertebrates, minimum-effect sediment levels were 5% and 13% for % fines and % sand and fines, respectively, both expressed as areal percentages of the wetted streambed surface. For aquatic macroinvertebrates, minimum-effect levels for the 2 sediment size classes were 3% and 10%, respectively. We encourage managers to consider these biologically based minimum-effect values when developing sediment criteria for mountain streams. Quantifying and comparing both vertebrate and macroinvertebrate assemblage responses to streambed sedimentation informs the criteria-setting process and allows managers to set stream restoration priorities.

Stream chemistry in the eastern United States: 1. Synoptic survey design, acid‐base status, and regional patterns

To assess the regional acid-base status of streams in the mid-Atlantic and southeastern United States, spring base flow chemistry was surveyed in a probability sample of 500 stream reaches representing a population of 64,300 reaches (224,000 km). Approximately half of the streams had acid-neutralizing capacity (ANC) ≤ 200 μeq L−1. Acidic (ANC ≤ 0) streams were located in the highlands of the Mid-Atlantic region (southern New York to southern Virginia, 2330 km), in coastal lowlands of the Mid-Atlantic (2600 km), and in Florida (462 km). Acidic streams were rare (less than 1%) in the highlands of the Southeast. Inorganic monomeric aluminum (Alim) concentrations were highest in acidic streams of the Mid-Atlantic Highlands where over 70% of the acidic streams had Alim greater than 100 μg L−l, a concentration above which deleterious biological effects have frequently been reported. Dissolved organic carbon concentrations were much higher in lowland coastal streams, compared with inland streams. Our data support a hypothesis that atmospheric sources and watershed retention control regional patterns in streamwater sulfate concentrations. Most stream watersheds retain the vast majority of the total nitrogen loading from wet deposition. The data suggest, however, that some deposition nitrogen may be reaching streams in the Northern Appalachians. These results show that acidic surface waters are found outside the glaciated northeastern portions of the United States and that watershed sulfate retention is not sufficient to prevent acidic conditions in some Mid-Atlantic Highlands streams.

Indicators of Ecological Stress and Their Extent in the Population of Northeastern Lakes: A Regional-Scale Assessment

Article reporting findings from the Environmental Protection Agency (EPA)s Environmental Monitoring and Assessment Program (EMAP) conducted on a sample of lakes in the Northeastern United States from 1991 to 1996.

National and regional comparisons between Strahler order and stream size

Abstract Water-body size is one of the most important factors affecting the structure and function of aquatic ecosystems. The categorical variable, Strahler stream order, is commonly used as a surrogate for stream size, perhaps because stream size is a multidimensional attribute that defies simple definition. Some stream-size attributes, including continuous variables, such as catchment area, distance to source, and model estimates of discharge also are available as geographic information system (GIS)-derived or modeled variables. These GIS measures are commonly used by stream ecologists along with field-derived attributes, such as discharge, stream cross-sectional area, width, and depth, which are more direct measures of stream size as experienced by aquatic organisms. Our objective was to quantify how well some commonly used stream-size attributes are predicted from Strahler order in the US as a whole and within major ecoregions and hydrologic landscape regions. We based our analysis on field-channel-survey and digital-stream-trace data (NHD-Plus) from 2162 US stream sites, ranging from 1st to 8th order (at 1∶100,000 scale). Strahler order provided a surprisingly useful approximation of the ranges of catchment size, distance to source, modeled mean annual discharge, and field-based low-flow and bankfull channel dimensions for most streams within a given Strahler order. However, even within geoclimatically and ecologically similar regions, site-specific predictions of stream size from Strahler order can have large errors. Correlations between Strahler order and the size measures considered here varied widely (r  =  0.48–0.91). Within individual Strahler orders, the alternative size measures varied by 5 and 4 orders of magnitude at national and regional scales, respectively. The same size-measure value could occur in 1 to 7 different stream orders at the national scale and in some regions, with generally good agreement in mountains and poor agreement in plains. Therefore, we conclude that Strahler order is useful for relating information about stream size, but that researchers should base analyses on multiple, continuous measures of stream size and should communicate stream-size results or associations based on the size-related measurements. Two characteristics of Strahler order make it useful for selecting sites across the range of stream sizes encountered in regional and national surveys, as long as limitations are explicitly recognized. First, the number of Strahler orders is limited. Second, Strahler order is easy to extract from stream networks constructed from digital elevation data and from national hydrographic data sets.

A Comparison of the Performance and Compatibility of Protocols Used by Seven Monitoring Groups to Measure Stream Habitat in the Pacific Northwest

Abstract To comply with legal mandates, meet local management objectives, or both, many federal, state, and tribal organizations have monitoring groups that assess stream habitat at different scales. This myriad of groups has difficulty sharing data and scaling up stream habitat assessments to regional or national levels because of differences in their goals and data collection methods. To assess the performance of and potential for data sharing among monitoring groups, we compared measurements made by seven monitoring groups in 12 stream reaches in northeastern Oregon. We evaluated (1) the consistency (repeatability) of the measurements within each group, (2) the ability of the measurements to reveal environmental heterogeneity, (3) the compatibility of the measurements among monitoring groups, and (4) the relationships of the measurements to values determined from more intensive sampling (detailed measurements used as a standard for accuracy and precision in this study). Overall, we found that some stre...

Importance of environmental factors for the richness and distribution of benthic macroinvertebrates in tropical headwater streams

Abstract: An understanding of the interactions among local environmental factors (e.g., physical habitat and water quality) and aquatic assemblages is essential to conserve biodiversity in tropical and subtropical headwater streams. We evaluated the relative importance of multiple physical and chemical habitat variables that influence the richness of Ephemeroptera, Plecoptera, and Trichoptera (EPT) assemblages in wadeable Brazilian Cerrado (savanna) streams. We sampled macroinvertebrate assemblages and quantified physical and chemical habitat in 79 randomly selected sites in 2 Cerrado basins in southeastern Brazil. The environmental variables selected by multiple regression models (MLRs) via corrected Akaike Information Criteria (AICc) contributed significantly to variation in EPT taxon richness. The variance explained by physical-habitat variables was slightly greater in the Upper São Francisco Basin (adjusted R 2 = 0.53) than in the Upper Araguari Basin (adjusted R 2 = 0.46), and both were greater than the variance explained by a combined basin model (adjusted R 2 = 0.39). Physical-habitat variables were more important than water-quality variables in structuring EPT genera in streams with catchments dominated by agriculture or pasture land uses. Regional models can be improved by incorporating basin-specific information to refine biological assessments and to provide better understanding of the interactions that maintain biodiversity in stream networks.

Sources of acidity in lakes and streams of the United States

Acidic (acid neutralizing capacity [ANC] < or = 0) surface waters in the United States sampled in the National Surface Water Survey (NSWS) were classified into three groups according to their probable sources of acidity: (1) organic-dominated waters (organic anions > SO4*; (2) watershed sulphate-dominated waters (watershed sulphate sources > deposition sulphate sources); and (3) deposition-dominated waters (anion chemistry dominated by inputs of sulphate and nitrate derived from deposition). The classification approach is highly robust; therefore, it is a useful tool in segregating surface waters into chemical categories. An estimated 75% (881) of acidic lakes and 47% (2190) of acidic streams are dominated by acid anions from deposition and are probably acidic due to acidic deposition. In about a quarter of the acidic lakes and streams, organic acids were the dominant source of acidity. In the remaining 26% of the acidic streams, watershed sources of sulphate, mainly from acid mine drainage, were the dominant source of acidity.