Sediment is often listed as one of the main contributors to the impairment of surface waters throughout the United States. Sediment source identification is difficult in watersheds with complex combinations of land-uses and non-point sources because of the complexities involved in correlating water quality data, which are relatively easy to collect, to the source of a degrading component. The elemental properties of a particular soil on the landscape may be viewed as a “fingerprint”. A comparison of the elemental fingerprints of potential sources and in-stream sediment may be used to establish sediment source. The objectives of this investigation were to characterize the elemental content of suspended stream sediment and potential sources of sediment in an impaired watershed, Pond Creek watershed in east Tennessee (HUC: TN06010201013), and to use multivariate statistical techniques to identify and quantify sediment sources in the watershed. Potential sediment source samples were collected throughout the watershed and suspended sediment samples at two locations. Subsamples of the <53>μm material and suspended sediment were subjected to total dissolution, HNO3-extraction, and Mehlich 3-extraction. Descriptive statistics suggested that each dataset contained considerable heterogeneity. The source samples were grouped according to land management and position in the landscape. The results of a Kruskal-Wallis rank test and discriminant function analysis indicated that for all three datasets the elemental variability of the samples was not sufficient to differentiate the source and sediment samples and characterize the suspended sediment sources using the initial group definitions. When using all available elemental data from each dataset the groups defined by cluster analysis and canonical discriminant analysis did not match the contents of the initially defined groups. The composition of the clusters varied from one dataset to another, making it difficult to draw conclusions concerning the cluster contents, or to identify sources of suspended sediment. The lack of elemental content variability for differentiating the source and sediment samples and characterizing the suspended sediment sources is likely an artifact of the watershed sampling procedure that was employed, which was directed towards sampling sources likely to be contributing to the suspended sediment load in Pond Creek.

The value of air quality improvement following the 1990 Clean Air Act Amendments is estimated at the county level in the lower 48 United States. This study applies a hedonic model to assess the economic benefits of air quality improvement using an instrumental variable approach that combines geographically weighted and spatial autoregression methods to account for spatial heterogeneity and spatial autocorrelation. Positive amenity values of improved air quality are found in five major clusters of areas across Eastern Kentucky and most of Georgia around Southern Appalachian area, the State of Illinois, on the border of Oklahoma and Kansas, on the border of Kansas and Nebraska, and Eastern Texas. The reason for the clusters of significant positive amenity values may be due to the combination of intense air pollution, consumers’ awareness of diminishing air quality, and higher marginal benefit of reductions of TSPs in communities with relatively low pollution levels. Surprisingly, negative amenity values of improved air quality are found in the three distinctive clusters of east Virginia, west and central Texas, and southeast Montana. This unexpected result may be explained by worsening air quality with intensive economic growth, greater appreciation in housing prices in those regions, and/or missing variables reflecting regionally specialized economic growth.

Groundwater-surface water interactions can substantially influence the quality of surficial water bodies and are thus important when investigating ecological health of and climate change impacts on an area. However, data collection can be hindered when the location is remote and/or legally protected. This paper presents a methodology to implement minimallyinvasive field techniques at a remote and protected location that allows preliminary identification of the relationship between groundwater and surface water. Great Smoky Mountains National Park was selected as the study area as it is subjected to some of the highest rates of acid deposition in the country. Ecological damage is evident in several areas, including Ramsay Prong, a typical fourth-order stream located on the Tennessee side of the park. Ramsay Prong is evaluated on the basis of discharge, water quality, geochemistry, and stable isotopes at six points along the channel. It should be noted that increasing drought conditions occurred in the basin over the course of this study, providing an opportunity to evaluate the situation of low baseflow. Results indicate that storage capacity in the headwaters is insufficient to supply typical baseflow volume during extended dry periods, whereas sufficient alluvium exists at the bottom of the catchment to capture and recharge the basin water supply. A shallow fracture network likely provides long flowpaths for water to travel toward the basin bottom. Furthermore, baseflow is supplied by interflow as well as shallow groundwater storage; the portion of baseflow comprised by interflow increases with increasing antecedent precipitation. Diffuse groundwater recharge occurs mainly in the headwaters where steep slopes dominate the topography, while focused recharge occurs in bedrock depressions within the reaches and at the end of the channel. These observations, coupled with geochemical and isotopic data, indicate that neutralization of acidic inputs is best accomplished in the lower elevations of the basin. It is recommended that future studies investigate the ecological impacts of reduced precipitation in terms of acid neutralization capabilities along Ramsay Prong.

Episodic stream acidification occurs as storm events temporarily reduce acid neutralizing capacity and pH. Stream acidification is suspected to have damaging effects on the health of aquatic ecosystems and biota and is dependent on various watershed characteristics such as drainage area, elevation, slope, and surficial geology. Here, a stochastic modeling approach is applied to continuous pH data for multiple stream monitoring sites within the Great Smoky Mountains National Park in order to characterize episodic acidification responses during stormflows for different streams. The approach summarizes voluminous pH data recorded by water quality sondes at 15-minute intervals into concentration-duration-frequency relationships. Unique to this study is the ability to characterize the episodic acidification response to watershed attributes without using baseflow or single-point stormflow measurements. A slope metric of mean pH event duration, a measure of episodic acidification response was determined to correlate with basin area and elevation. In contrast, baseflow studies have shown elevation to be the main driver of chronic acidification. It appears that during stormflows transport and flushing of stored anions and cations govern the response of streams included in this study.

A bacterial source tracking study using Bacteroides host associated real-time PCR assays was performed to determine the sources of fecal contamination in Pond Creek (HUC 06010201013). Pond Creek, located in the Ridge and Valley physiographic region in Eastern Tennessee, is a 303(d) listed stream that fails to meet water quality standards for pathogens. Water samples and discharge were measured monthly at eight locations from November 2005 to November 2006. Grab samples were analyzed for several chemical parameters and for microbial fecal indicator organisms, namely Bacteroides spp., Escherichia coli, and Enterococcus. The objectives of the study were to quantify total, human, and bovine associated Bacteroides. Additionally, we investigated spatial and temporal variation of fecal indicator organisms and created load duration curves for each sampling site. The results showed that Escherichia coli concentrations regularly exceeded water quality standards. Bacteroides host associated real-time PCR assays indicated that cattle were the dominant source of fecal pollution (99 percent of total Bacteroides). Although human-associated Bacteroides were detected, their concentrations remained relatively low across the watershed. Load data show that fecal contamination from bovine sources occurs at elevated levels throughout the watershed; no statistical differences between sites were observed for bovine associated Bacteroides (BoBAC) and Bacteroides spp. belonging to the Bacteroides genus (AllBAC) loads. Additionally, bovine-associated Bacteroides concentrations were very highly correlated (r2 = .903) with the total Bacteroides concentrations. Load Duration Curves (LDCs) also indicated extensive bovine fecal pollution. Load data separated into human and bovine LDCs showed that Escherichia coli loads from bovine sources were mostly flow dependent whereas human associated Escherichia coli loads were generally flow independent. Temporal variations followed seasonal weather patterns; mean loads of all fecal indicators, except Enterococcus, were greatest during the months of highest precipitation and lowest in the drier months. No temporal patterns were established for concentrations of fecal indicator organisms. This suggests that runoff transported the majority of fecal inputs to Pond Creek. Best management practices (BMPs) such as improving pastures, nutrient management, proper manure storage, controlling livestock stocking densities, vegetative filter strips, and riparian fencing with careful riparian grazing, should be implemented to reduce fecal inputs from cattle and help Pond Creek meet TMDL guidelines.

We investigated, under long-term no-till in western Tennessee, the effects of rotating the low-input crops cotton and soybeans with the high-input crop corn, compared to continuous monocultures of cotton and soybeans, and of using the winter cover crops (WCCs) winter wheat and hairy vetch, compared to winter fallow, on key indicators of soil health concerning vegetative cover and labile SOM. The line-transect method was used to measure percent vegetative cover. Dry weight of surface crop residue and aboveground living plant biomass (WCCs and winter weeds) was obtained. The living plant biomass was analyzed for carbon (C) and nitrogen (N) by dry combustion to determine C/N ratios. The sand-sized POM-C fraction at 0 to 5 and 5 to 15 cm was physically fractionated and analyzed for C by dry combustion. The inclusion of corn in rotation with cotton significantly increased aboveground crop residue quantity, aboveground winter weed biomass quantity, total aboveground biomass quantity, percent vegetative cover, and POM-C at 0 to 5 cm. The inclusion of corn in rotation with soybeans significantly increased aboveground crop residue quantity and POM-C at 0 to 5 cm, but significantly decreased aboveground winter wheat biomass quantity, total aboveground biomass quantity under winter wheat, aboveground winter weed biomass C/N ratio, and POM-C at 5 to 15 cm. The use of WCCs did not significantly increase total aboveground biomass quantity under most cropping sequences, and significantly reduced aboveground crop residue quantity, aboveground winter weed biomass quantity, and percent vegetative cover. The WCCs generally did not affect POM-C at either depth, though they significantly increased POM-C at 5 to 15 cm under continuous soybeans. Compared to winter wheat, hairy vetch significantly increased aboveground winter weed biomass quantity and percent vegetative cover. Our results demonstrate that the inclusion of corn in rotation with cotton is highly effective, while inclusion of corn in rotation with soybeans and the use of WCCs are ineffective in improving soil quality by increasing vegetative cover and the labile pool of SOM under these conditions.

In order to accurately predict the stability of riverbanks, model input parameters must be reliable bank failure estimators. Currently, bank stability models require two input parameters to predict bank erosion: critical erosion shear stress and erodibility coefficient. The investigation’s purpose was to compare two erosion estimation methods and improve the bank stability models for cohesive soil commonly found on the banks. To accomplish the objective, critical shear stresses and erodibility coefficients obtained using the in situ submerged jet test device (SJT) were measured against results from the closed-loop laboratory flume method for 12 cohesive bank sites. Additionally, SJT critical shear stress values were compared to values found via empirical relationships found in literature that incorporate plasticity index, median particle diameter, percent siltclay or percent clay content to compute critical shear stress. Particle size analysis and Atterberg limit determinations were run classify the sediment type collected. The critical shear stress values obtained ranged from 0.09 to 5.84 Pa and SJT erodibility coefficients varied from 0.37 to 10.07 cm3/N·s. From flume observations, cohesive soil erosion was influenced by interparticle forces and occurred in aggregate pieces and particle-by-particle. A few critical shear stress values appeared to be unreliable considering the critical shear stress threshold of 1.83 Pa found using the laboratory flume analysis and the limited erosion witnessed. Study results also indicated that sediment properties did not correlate directly with the SJT critical shear stress values or with each other. Flume observations and variations among experimental results suggest other influential factors exist besides critical shear stress and the erodibility coefficient when quantifying the cohesive sediment erosivity. When empirical results were lower than the flume’s critical shear stress threshold, it was possible the mechanical soil property could not be transferred to the soil types tested or estimates incorrectly assumed zero physical and chemical influences. Because of its complexities, traditional experimental design may not reliably measure cohesive soil erosion. Only through the continued collaboration of various field and advanced degree professionals and the detailed, high-quality documentation of as many influential parameters as possible per project can the goal of estimating cohesive sediment erosion be accomplished.

This study attempts to develop a relationship with the hillslope sediment yield (estimated from a computer model) and the deposited sediment particle size characteristics within stream channels. By using specific hydrological parameters within a watershed, a calibrated Annualized Agricultural Non-Point Source (AnnAGNPS) pollutant loading model was created for four different sub-watersheds in the mountainous New River Basin of eastern Tennessee. The AnnAGNPS pollutant loading model predicted daily runoff and sediment yield reasonably well, but it poorly predicted daily peak flow rate for most sub-watersheds analyzed in the New River Basin. Overall, the AnnAGNPS pollutant loading model provided satisfactory results in a mountainous, nonagricultural landscape with a limited amount of climatic data available. The average annual hillslope sediment yield, in terms of clays, silts, and sands, was calculated with the AnnAGNPS model for years 2006 and 2007, to compare with sediment deposition characteristics in the streams. The fine particle size characteristics collected at specific bed deposition points were suspected to have a strong correlation with predicted sediment yield output from a calibrated AnnAGNPS pollutant loading model. The sites of the captured sediment were at locations just downstream of specific land use disturbances such as dirt roads, surface mining, and forest logging, all of which can be detrimental to the health of a stream environment and habitat if disturbances are not properly managed. In this study, the sediment collected at the channel bed deposition points represented the distribution of different material sizes that have recently moved within the stream during large discharge events. This investigation concluded that the certain measurements of the clays, silts, sands, and gravel material found in downstream sediment depositional points had a variety of significant relationships (p-value < 0.05) with the clays, silts, sands, and total sediment yield occurring on the watershed hillslopes. Overall, there are a limited amount of studies that analyze these collections of fine sediment deposited in areas of the stream that have interrupted velocity forces due to channel shape, objects, or formations. This study showed that the use of the AnnAGNPS pollutant loading model and the analyzation of specific fine sediment at depositional points in the stream, proper watershed management of a rural mountainous region can be better established.

Agricultural runoff is a leading non-point source contributor to water quality impairment in the United States and is associated with eutrophication of surface waters. Phosphorus (P) is often the most limiting nutrient for eutrophication in freshwaters. The objectives of this study were to characterize the P forms in surface runoff from an agricultural field that has received long-term applications of liquid dairy manure and to determine the forms of soil P that occur within a sinkhole feature located within the application field. Three 21-m x 6 m bermed plots were established to collect storm water runoff from a portion of the study site which drains into the sinkhole. The runoff collected was analyzed for total P (TP), dissolved reactive phosphorus (DRP), total dissolved P (TDP), dissolved organic phosphorus (DOP), and particulate P (PP). Soils were sampled from various elevations within the sinkhole feature and were analyzed for TP, total organic P (TOP), Mehlich-3 extractable P, and the maximum P sorption capacity. The results showed a precipitous increase in TP of surface runoff after manure application, from 2.2 g ha-1 to 21.9 g ha-1. The majority of P leaving the field as runoff prior to manure application was associated with the PP fraction (63% of TP). Surface runoff from two rainfall events occurring after diary manure was applied consisted predominately of DRP (67% of TP). Dissolved reactive P in runoff ranged from 0.02 to 0.2 mg L-1 before manure application and 7.1 to 17.1 mg L-1 after application. It has been reported that DRP concentrations in the low ìg/L range can negatively stimulate aquatic vegetation growth in P-limited waters, which indicates the runoff leaving the study site has the potential to impair water quality. A statistically significant difference existed for soil TP concentrations at different elevations within the sinkhole feature, ranging from 3116 mg kg-1 in the base to 914 mg kg-1 in the higher elevations of the sinkhole. A slight increase in TOP concentrations from the base (407 mg kg-1) to the higher elevations of the sinkhole (513 mg kg-1) occurred. The measured maximum P sorption capacity of soils within the sinkhole feature showed that these soils can potentially sorb between 284-379 mg kg-1 of P indicating that the soils are not P saturated and are capable of fixing additional P from runoff.

Groundwater-surface water interactions have been shown to be important to flow generation and stream chemistry in upland catchment environments. These areas, however, are often difficult to access making the implementation of standard hydrological surface and subsurface monitoring equipment and characterization procedures impractical, arduous and in many cases impossible due to the nature of the terrain and also regulatory guidelines for protected areas. By collecting surface water samples at distinct water contribution sites to a headwater stream, areas of groundwater influence were inferred and a hydrochemical conceptual model of a small basin was created. The objectives of this research were to 1) understand the groundwater chemistry influences to an upland stream in the Great Smoky Mountains National Park (GSMNP) using limited surface water data 2) determine if the use of multivariate statistics could help delineate water interaction “types” within the study basin, 3) create a conceptual model to define the chemical interactions in the stream using a comparison of data. The objectives were met by the analyses of field data collected within Ramsey Prong, a remote forested, high elevation stream in the Middle Prong Little Pigeon River Watershed chosen for the study site. Eight sampling sites were selected at hydrologic and hydrochemically significant points in the basin. Three data collection trips were performed in April, July, and August of 2007. Water sampled for analysis of cations, anions, and trace metals was collected and flow measurements were recorded on each trip at each site. Multivariate analyses were conducted on the collected data to detect correlations between parameters that might indicate similar chemistries or water interaction “types” where high correlations were displayed. Three water types: 1) surface water; 2) spring water; and 3) a top of catchment mixture of spring and highly acidic deposition and drainage water were delineated. Spring 1, located at the bottom of the study area, was designated as the first water type and displayed high concentrations of Si, Na, ANC, and pH. The source of this water was affirmed by groundw32ater characteristics caused by the sandstone subsurface environment. The second water type, consisting of the two highest elevation sample sites, displayed characteristics of acid deposition and acid-rock or acid induced leaching including, low pH and ANC and high levels of SO4, Mn, Fe, and Al ions. Increased levels of Si and Na also suggested groundwater interaction further up the sampled tributary. Water designated as the third water type consisted of the remaining in-stream samples which demonstrated a trend of general dilution in most atmospherically input ions and a concentrating of geochemical parameters. Large areas of focused recharge signatures were not detected in the study area leading to the assumption of primarily diffuse recharge throughout the stream. Two tributaries sampled on the August collection date displayed groundwater chemistries with a different signature than that of the stream and showed indications of water quality buffering. The analysis demonstrated the possibility for influential stream buffering in the GSMNP by groundwater and groundwater sourced inputs and also the importance of groundwater in this system.