Appendix 2.2 Graphs Showing Data Distributions for Organic Contaminants in Whole Sediment Sampled in Response to the Deepwater Horizon Oil Spill, 2010...............................87

Appendix 2.3 Graphs Showing Data Distributions for Trace and Major Elements, Nutrients, and Specific Conductance in Water Sampled in Response to the Deepwater Horizon Oil Spill, 2010................................................147

Appendix 2.4 Graphs Showing Data Distributions for Trace and Major Elements in Whole Sediment Sampled in Response to the Deepwater Horizon Oil Spill, 2010...............................................165

Appendix 2.5 Graphs Showing Data Distributions for Trace and Major Elements in the Less Than 63-Micrometer Fraction of Sediment Sampled in Response to the Deepwater Horizon Oil Spill, 2010..................................183

Few organic contaminants were detected in water; their detection frequencies generally were low and similar in pre-landfall and post-landfall samples. Only one organic contaminant—toluene—had significantly higher concentrations in post-landfall than pre-landfall water samples. No water samples exceeded any human-health benchmarks, and only one post-landfall water sample exceeded an aquatic‑life benchmark—the toxic-unit benchmark for polycyclic aromatic hydrocarbons (PAH) mixtures. In sediment, concentrations of 3 parent PAHs and 17 alkylated PAH groups were significantly higher in post‑landfall samples than pre-landfall samples. One pre‑landfall sample from Texas exceeded the sediment toxic‑unit benchmark for PAH mixtures; this site was not sampled during the post-landfall period. Empirical upper screening-value benchmarks for PAHs in sediment were exceeded at 37 percent of post-landfall samples and 22 percent of pre-landfall samples, but there was no significant difference in the proportion of samples exceeding benchmarks between paired pre-landfall and post‑landfall samples. Seven sites had the largest concentration differences between post-landfall and pre-landfall samples for 15 alkylated PAHs. Five of these seven sites, located in Louisiana, Mississippi, and Alabama, had diagnostic geochemical evidence of Macondo-1 oil in post-landfall sediments and tarballs.

For trace and major elements in water, analytical reporting levels for several elements were high and variable. No human-health benchmarks were exceeded, although these were available for only two elements. Aquatic-life benchmarks for trace elements were exceeded in 47 percent of water samples overall. The elements responsible for the most exceedances in post-landfall samples were boron, copper, and manganese. Benchmark exceedances in water could be substantially underestimated because some samples had reporting levels higher than the applicable benchmarks (such as cobalt, copper, lead and zinc) and some elements (such as boron and vanadium) were analyzed in samples from only one sampling period. For trace elements in whole sediment, empirical upper screening-value benchmarks were exceeded in 57 percent of post-landfall samples and 40 percent of pre‑landfall samples, but there was no significant difference in the proportion of samples exceeding benchmarks between paired pre-landfall and post-landfall samples. Benchmark exceedance frequencies could be conservatively high because they are based on measurements of total trace-element concentrations in sediment. In the less than 63-micrometer sediment fraction, one or more trace or major elements were anthropogenically enriched relative to national baseline values for U.S. streams for all sediment samples except one. Sixteen percent of sediment samples exceeded upper screening-value benchmarks for, and were enriched in, one or more of the following elements: barium, vanadium, aluminum, manganese, arsenic, chromium, and cobalt. These samples were evenly divided between the sampling periods.

Aquatic-life benchmarks were frequently exceeded along the Gulf of Mexico coast by trace elements in both water and sediment and by PAHs in sediment. For the most part, however, significant differences between pre-landfall and post‑landfall samples were limited to concentrations of PAHs in sediment. At five sites along the coast, the higher post-landfall concentrations of PAHs were associated with diagnostic geochemical evidence of Deepwater Horizon Macondo-1 oil.

Water-level changes from predevelopment to 2011, by well, ranged from a rise of 85 feet to a decline of 242 feet. The area-weighted, average water-level changes in the aquifer were an overall decline of 14.2 feet from predevelopment to 2011, and a decline of 0.1 foot from 2009–11. Total water in storage in the aquifer in 2011 was about 2.96 billion acre-feet, which was a decline of about 246 million acre-feet since predevelopment.

A four-metric score (total taxa richness, Ephemeroptera plus Plecoptera plus Trichoptera taxa richness, Macroinvertebrate Biotic Index, and Shannon Diversity Index) for richest-targeted habitat was used to calculate a Stream Condition Index (SCI) in order to evaluate the aquatic-life status of the streams. About 80 percent of all samples combined were determined to be less than fully biologically supporting, and about 11 percent of spring samples were fully biologically supporting. No sites within the Blue River Basin had a fully supporting score. The aquatic-life status scores for the Little Blue River and its tributaries were higher (indicating more optimal conditions) than for the Blue River and its tributaries. Fall samples scored higher than spring samples. However, fall samples were collected at the Little Blue River Basin and rural sites only. The Little Blue River sites scored higher for fall samples than spring samples; about 39 percent fully biologically supporting and 61 percent partially biologically supporting; more similar to the rural comparison sites, 40 percent fully biologically supporting and 60 percent partially biologically supporting.

The SCI was compared to other multimetric indices with more or other component metrics to determine if the SCI effectively described differences among sites. Environmental variables (streamflow, water quality, land use, impervious cover, and population density) were used in statistical analyses to evaluate relations to macroinvertebrate metrics. Multimetric indices (MMIs) were modeled using step regression with a simple urban intensity index (SUII) based on percentage of impervious cover, population density, and forest cover in a 30-meter stream-buffer zone, and two were selected for further analysis. Three other multimetric indices composed of metrics common to local and national studies show results similar to the two modeled MMIs. A common Benthic Index of Biotic Integrity (R² equals 0.71) developed for a national study had the highest correlation with urban intensity as measured with the SUII, followed by a modeled 6-metric index (R² equals 0.61). The other MMIs and the SCI explained less than a half of the variability in macroinvertebrate communities in relation to the SUII.

Wastewater-treatment plant discharges during base flow, which elevated specific conductance and nutrient concentrations, combined sewer overflows, and nonpoint sources likely contributed to water-quality impairment and lower aquatic-life status at the Blue River Basin sites. Releases from upstream reservoirs to the Little Blue River likely decreased specific conductance, suspended-sediment, and dissolved constituent concentrations and may have benefitted water quality and aquatic life of main-stem sites. Chloride concentrations in base-flow samples, attributable to winter road salt application, had the highest correlation with the SUII (Spearman’s ρ equals 0.87), were negatively correlated with the SCI (Spearman’s ρ equals -0.53) and several pollution sensitive Ephemeroptera plus Plecoptera plus Trichoptera abundance and percent richness metrics, and were positively correlated with pollution tolerant Oligochaeta abundance and percent richness metrics. Study results show that the easily calculated SUII and the selected modeled multimetric indices are effective for comparing urban basins and for evaluation of water quality in the Kansas City metropolitan area.

The Roanoke logperch is a large darter (Percidae: Etheostomatinae) endemic to the Roanoke, Dan, and Nottoway River basins of Virginia and North Carolina, where it occupies third- to sixth-order streams containing relatively silt-free substrate (Jenkins and Burkhead, 1994). Because of its rarity, small range, and vulnerability to siltation, the Roanoke logperch was listed in 1989 as endangered under the U.S. Endangered Species Act (ESA) (U.S. Federal Register 54:34468-34472).

Within the Dan basin, Roanoke logperch have long been known to occupy the Smith River and one of its largest tributaries, Town Creek (Jenkins and Burkhead, 1994). Logperch also recently were discovered in other tributaries of the Dan River, including North Carolina segments of the Mayo River, Cascade Creek, Big Beaver Island Creek, Wolf Island Creek (William Hester, U.S. Fish and Wildlife Service, personal commun., 2012). Within the Smith River, Roanoke logperch are present both upstream and downstream from Philpott Reservoir, a hydroelectric and water storage project owned and operated by the USACE. Although logperch have not been observed in the reservoir itself, the species is relatively abundant in a free-flowing, ≈ 2.5-km-long segment of Smith River upstream from the reservoir on USACE property (Lahey and Angermeier, 2006). This segment is bounded on the downstream end by the lentic conditions of the reservoir and on the upstream end by White Falls, a natural waterfall that presumably allows fish passage during all but the lowest streamflows (Roberts and Angermeier, 2009; fig. 1).

The ESA stipulates that USACE must ensure that its actions do not jeopardize Roanoke logperch and ensure that appropriate actions are taken to aid in the recovery of Roanoke logperch. USACE recognized that additional information was needed to assess compliance with these stipulations, including data on baseline population levels, habitat availability, and potential threats to the species on USACE property. USACE therefore contracted with Virginia Tech (VT) and the U.S. Geological Survey via the Virginia Cooperative Fisheries and Wildlife Research Unit (VCFWRU) to continue ecological monitoring that was initiated in a pilot study in 2005 (Lahey and Angermeier, 2006). The VCFWRU is jointly sponsored by the U.S. Geological Survey, Virginia Tech, Virginia Department of Game and Inland Fisheries, and Wildlife Management Institute.

This final report summarizes results of biological monitoring performed by VT and the VCFWRU in 2011, and compares these data to data collected during 2006–2010 (Roberts and Angermeier, 2011). Where appropriate, a comparison was made to data on Roanoke logperch collected previously in the study reach (Lahey and Angermeier, 2006) and in the upper Roanoke River (Roberts and Angermeier, 2011). This work was performed under the auspices of VT’s Institutional Animal Care and Use Committee (IACUC) protocol 11-035-FIW. Specifically, the following objectives were addressed:

• Estimate population density of Roanoke logperch on USACE property;

• Measure and map by suitability class the distribution of habitat suitable for Roanoke logperch in the project area;

• Assess water quality relative to Roanoke logperch habitat in the project area;

• Use the data on logperch abundance, habitat suitability,and water quality to test the general validity of corre-lates of logperch abundance from other locations;

• Identify opportunities and threats related to protecting and enhancing Roanoke logperch habitat; and

• Provide suggestions on the necessity and scale of future studies and monitoring related to logperch in and near USACE waters.

There are four active coal mines in the MTPRB assessment area: the Spring Creek and Decker Mines, both near Decker; the Rosebud Mine, near Colstrip; and the Absaloka Mine, west of Colstrip. During 2011, coal production from these four mines totaled approximately 36 million short tons (MST). A fifth mine, the Big Sky, had significant production from 1969–2003; however, it is no longer in production and has since been reclaimed. Total coal production from all five mines in the MTPRB assessment area from 1968 to 2011 was approximately 1.4 billion short tons (BST). The Rosebud/Knobloch coal bed near Colstrip and the Anderson, Dietz 2, and Dietz 3 coal beds near Decker contain the largest deposits of surface minable, low-sulfur, subbituminous coal currently being mined in the assessment area.

A total of 26 coal beds were identified during this assessment, 18 of which were modeled and evaluated to determine in-place coal resources. The total original coal resource in the MTPRB assessment area for the 18 coal beds assessed was calculated to be 215 BST. Available coal resources, which are part of the original coal resource remaining after subtracting restrictions and areas of burned coal, are about 162 BST. Restrictions included railroads, Federal interstate highways, urban areas, alluvial valley floors, state parks, national forests, and mined-out areas.

It was determined that 10 of the 18 coal beds had sufficient areal extent and thickness to be evaluated for recoverable surface resources ([Roland (Baker), Smith, Anderson, Dietz 2, Dietz 3, Canyon, Werner/Cook, Pawnee, Rosebud/Knobloch, and Flowers-Goodale]). These 10 coal beds total about 151 BST of the 162 BST of available resource; however, after applying a strip ratio of 10:1 or less, only 39 BST remains of the 151 BST. After mining and processing losses are subtracted from the 39 BST, 35 BST of coal were considered as a recoverable resource. Coal reserves (economically recoverable coal) are the portion of the recoverable coal resource that can be mined, processed, and marketed at a profit at the time of the economic evaluation. The surface coal reserve estimate for the 10 coal beds evaluated for the Montana Powder River assessment area is 13 BST.

It was also determined that about 42 BST of underground coal resource exists in the MTPRB assessment area; about 34 BST (80 percent) are within 500–1,000 ft of the land surface and another 8 BST are 1,000–2,000 ft beneath the land surface.