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The major study objectives include determining if a 50-foot streamside management zone (SMZ) as described in the Virginia BMP Manual (VDOF 2002) is generally sufficient to protect stream water quality, riparian soils, and stream bank integrity in headwater streams where forest harvesting has taken place, as well as comparing other SMZ widths with regard to the same environmental protection performance. In 2003, 16 forested watersheds were clear-cut harvested for commercial timber production. Four SMZ treatments were installed across four experimental blocks during harvest. Each of the 16 watersheds was subsequently site-prepared with prescribed burning and planted with loblolly pine (Pinus taeda). Within the watersheds, the established treatments were a 100-foot width with no thinning, a 50-foot width without thinning, a 50-foot width with thinning, and a 25-foot "stringer." Each of the four treatments was conducted within three of four blocks (Incomplete Block Design). After a two-year post-harvest monitoring period, it was determined that the SMZ treatments had no significant effect on water quality, channel geometry, or soil erosion in and around the streams. There was no apparent water quality degradation as a result of harvesting timber, and larger SMZs did not have an impact on any of the parameters studied. It was also apparent that leaving narrower SMZs or thinning within SMZs did not cause any apparent environmental degradation. It was also determined that landowners who leave SMZs on their property have very limited opportunities to manage timber within them for financial gain in the long term. / Ph. D.

Headwater catchments play a large role in the storage and release of water and chemical constituents, thereby influencing downstream flows and water quality. Recent advances in water quality monitoring technologies have created an opportunity to better assess water chemistry variation by using high temporal resolution, in situ sensors. However, despite these new technologies, there have been limited studies on installation approaches and their effects on sensor measurements. Accurate in situ monitoring is particularly important to capture catchment disturbance effects that may be highly dynamic over time (e.g., following storms) or limited in duration. For example, prescribed fire is a commonly applied forest management tool, but there remain questions regarding how this disturbance affects catchment soils and resultant stream water chemistry. Effective assessment of prescribed fire thus requires coupled monitoring of both soil properties and water chemistry. In this thesis, I addressed two linked objectives: i) assess the effects of commonly used protective housings on in situ sensor measurements (Chapter 2) and ii) evaluate prescribed burn effects in a southwestern Virginia, USA headwater catchment (Chapter 3). In Chapter 2, I compared four different housing types (mesh, screen, holes, and open) using in situ specific conductance measurements over time and from salt tracer injections for discharge estimates. This study demonstrated substantial effects from some of the housing types evaluated, where flow resistance reduced water exchange between stream water and water in contact with the sensor. From these findings, I suggest that in situ water quality sensors should be deployed in housing types with large openings perpendicular to flow. In Chapter 3, I assessed prescribed fire effects on soil properties (particle size, aggregate stability, and chemistry), stream discharge, and fine-scale water chemistry dynamics. Findings demonstrated some significant differences following fire in soil properties (e.g., overall decrease in aggregate stability, general decreases in total carbon and nitrogen of mineral soils), water quality (e.g., increased levels of DOC, turbidity, and nitrate) and discharge (increases in stage and flow). While these changes were statistically significant, differences in parameters before and after fire were generally small. Future work should examine if these effects persist through time, and whether the minor level of disturbance observed in this study results in any negative environmental impacts. / Master of Science / Headwater catchments (where precipitation first becomes streamflow) provide important aquatic habitat and regulate downstream water flows and chemistry. Recent advances in water quality monitoring technologies have created an opportunity to better assess water chemistry variability by using high frequency, submerged water quality sensors. However, these new technologies present new, unique challenges, such as measurement errors that may be induced by different installation methodologies. Accurate measurements are particularly important to evaluate how changes in catchment conditions (e.g., soils, vegetation) impact local and downstream water quality. For example, prescribed fire is a commonly used forest management tool, but questions remain about how it affects catchment soils and headwater stream chemistry. Consequently, understanding the effects of this and other catchment disturbances requires coupled monitoring of both soil properties and water quality. In this thesis, I addressed two objectives: i) assess the effects of commonly used protective housings on water quality sensor measurements (Chapter 2) and ii) evaluate prescribed burn effects in a southwestern Virginia, USA headwater catchment (Chapter 3). In Chapter 2, I demonstrated substantial effects from some of the housings evaluated and suggest that water quality sensors should be deployed in housing types with large openings perpendicular to flow. In Chapter 3, I demonstrated some significant effects of prescribed fire on soil properties (e.g. overall decrease in soil stability, general decreases in total carbon and nitrogen of mineral soils), water quality (e.g., increased levels of dissolved organic matter, turbidity, and nitrate) and flow (increases in stream water levels and flow). While these changes were statistically significant, differences in parameters before and after fire were generally small. Future work should examine if these effects persist through time, and whether this minor level of disturbance causes any negative environmental impacts.

Large-scale land uses such as residential wastewater discharge and coal mining practices, particularly surface coal extraction and associated valley fills, are of particular ecological concern in central Appalachia. Identification and quantification of both large-scale land use and microhabitat alterations to ecosystems are a necessary first-step aid in mitigation of negative consequences to biota. In central Appalachian headwater streams absent of fish, salamanders are the dominant, most abundant vertebrate predator providing a significant intermediate trophic role. Stream salamander species are considered to be sensitive to aquatic stressors and environmental alterations with past research having shown linkages among microhabitat parameters, and large-scale land use such as urbanization and logging to salamander abundances. However, there is little information examining these linkages in the coalfields of central Appalachia. In the summer of 2013, I visited 70 sites (sampled three times each) in the southwest Virginia coalfields to collect salamanders and quantify stream and riparian microhabitat parameters. In an information-theoretic framework I compared the effects of microhabitat and large-scale land use on salamander occupancy and abundances. My findings indicate that dusky salamander (Desmognathus spp.) occupancy and abundances are more correlated to microhabitat parameters such as canopy cover than to subwatershed land uses. Brook salamander (Eurycea spp.) occupancy show negative associations to large-scale land uses such as percent recent mining and percent forested. Whereas Eurycea spp. abundances are negatively influenced by suspended sediments, stream bank erosion and stream substrate embeddedness. Management implications of these findings include erosion prevention and control as well as protection and management of riparian habitats. However, quantifying physical environmental quality such as stream and riparian habitat often can be quite difficult, particularly when there are time or fiscal limitations. In order to accurately assess stream and riparian habitat in a time- and cost- effective manner, the U.S. Army Corps of Engineers (USACE) developed a functional condition index (FCI) assessment for streams that measures 11 stream and riparian parameters along with watershed land use to calculate three different scores: a hydrology score, biogeochemical score, and habitat score (Noble et al 2010). Using the salamander data from 2013, I then analyzed the FCI scores using collected occupancy and abundance analyses. Both analyses supported the Habitat FCI score as it had strong correlations with both occupancy and abundance of three Desmognathus spp., and support the use of the USACE protocol for stream and riparian habitat assessment. / Ph. D.

Prior studies have demonstrated Appalachian coal mining often causes elevated specific conductance (SC) in streams, and others have examined SC effects on benthic macroinvertebrate communities using point-in-time SC measurements. However, both SC and benthic macroinvertebrate communities exhibit temporal variation. Twelve Appalachian headwater streams with minimally impacted physical habitat and reference-quality physicochemical conditions (except elevated SC) were sampled ten to fourteen times each for benthic macroinvertebrates between June 2011 and November 2012. In situ loggers recorded SC at 15-minute intervals. Streams were classified by mean SC Level (Reference 17-142 S/cm, Medium 262-648 S/cm, and High 756-1,535 S/cm). Benthic macroinvertebrate community structure was quantified by the Virginia Stream Condition Index and other metrics. Structural metric differences among SC Levels and month of sampling were explored. Reference-SC streams exhibited significantly higher scores on most metrics, supporting previous findings that SC may act as a biotic stressor, even in streams lacking limitations from degradation of physical habitat or other physicochemical conditions. Temporal variation was greatest in Medium-SC streams, which had the most metrics exhibiting significant differences among months and the greatest range of monthly means for six metrics. Metrics involving % Plecoptera and/or % Trichoptera were not sensitive to elevated SC, as Leuctridae and Hydropsychidae exhibited increased abundance in streams with elevated SC. Best scores for benthic macroinvertebrate community metrics differed based on selected metric, SC Level, and month. Consequently, timing of sampling is important, particularly in streams with elevated SC because community metric scores may be impacted by dominant taxa life history patterns. / Master of Science

Les techniques d’échantillonnage passif comme le POCIS (« Polar Organic Chemical Integrative Sampler ») ou le o-DGT (« Diffusive Gradient in Thin films » pour composés organiques) permettent d’obtenir une bonne représentativité de la contamination des eaux de surface par les micropolluants organiques. Cependant, ces dispositifs sont soumis à des conditions environnementales qui engendrent des biais sur la quantification des analytes cibles. Une meilleure connaissance des données issues de l’échantillonnage passif a donc été essentielle afin de les utiliser sur deux têtes de bassin versant. Pour cela un dispositif innovant, utilisant la technique DGT, a été développé et testé sur 4 pesticides ioniques. La robustesse du o-DGT étudiée sur une plage de pH allant de 3 à 8 et de force ionique allant de 0,01 à 1 mol.L-1, lui permette d’être utilisé dans la plupart des eaux naturelles. Des déploiements en milieu naturel et dans une rivière artificielle, en même temps que le déploiement de POCIS, a permis de comparer les performances de ces 2 échantillonneurs. Le POCIS, avec des limites de quantification plus basses, était l’échantillonneur le plus adapté au suivi de contamination des têtes de bassin versant, cependant il a été nécessaire de l’améliorer pour fiabiliser les concentrations de micropolluants mesurées.. Une libération de polyéthylène glycol issu des membranes utilisées pour la fabrication de POCIS provoquant des effets de matrice a été supprimé grâce à deux bains successifs d’1h d’un mélange 50:50 méthanol:eau suivi d’un bain de rinçage à l’eau. De même, une quantification des molécules cibles est obtenue grâce à des taux d’échantillonnage (Rs) déterminés dans conditions proches de celle de l’environnement. Les Rs de 44 molécules pharmaceutiques ont été déterminés grâce à une rivière artificielle. Après cette étape de fiabilisation, le POCIS a été appliqué à deux têtes de bassin versant avec des suivis de 1 et 3 ans sur, respectivement, l’Aixette et l’Auvézère. Des prélèvements ponctuels ont également été réalisés et ont pu mettre en évidence des pics de pollution de pesticides (> 2,3 g.L-1). Ces suivis « semi-continus » ont permis de mettre en évidence et de caractériser l’existence d’une pollution des têtes de bassin versant par les pesticides et les résidus pharmaceutiques. / Passive samplers, such as POCIS (Polar Organic Chemical Integrative Sampler) or o-DGT (Diffusive Gradient in Thin films for organic compounds), allow to estimate surface water contamination by organic micropollutants. However, these devices are influenced by environmental conditions and quantification error can occur. A better knowledge of passive sampling data was therefore essential before the samplers’ application on headwater streams. An innovative sampler, using DGT technique, has been developed and tested on 4 ionic pesticides. The sampler is robust in a pH range from 3 to 8 and an ionic strength range from 0,01 to 1 mol.L-1, which allows to use it in the most of natural waters. Field deployments of POCIS alongside o-DGT in natural waters and in an artificial river made it possible to compare their performances. POCIS with lower limits of quantification was the most suitable sampler for monitoring organic compounds in headwater stream. A release of polyethylene glycol from membranes used in POCIS causing matrix effects was removed by two successive baths of 1h of a 50:50 mix of methanol:water followed by a rinsing bath of water. Quantification is achieved through sampling rates (Rs) estimated under revelant conditions. Rs of 44 pharmaceuticals were estimated in an artificial river. After these steps, POCIS was applied in two headwater streams for 1 and 3 years on Aixette and Auvézère, respectively. Grab samples were also collected and pollution peaks of pesticides were detected (> 2,3 g.L-1). These “semi-continuous” monitorings highlighted a pollution of headwater streams by pesticides and pharmaceuticals.