Creek Watershed Research Articles

Effects of surface runoff and infiltration partition methods on hydrological modeling: A comparison of four schemes in two watersheds in the Northeastern US

Surface runoff and infiltration partition is a primary process of hydrologic cycle. Here, we compare four different surface runoff and infiltration partition methods within a Richards-equation-based SWAT model (RSWAT) to understand their effects on watershed modeling. Four surface runoff and infiltration partition methods include a Daily Curve Number method (DCN-RSWAT), a Hourly Curve Number method (HCN-RSWAT), a Green-Ampt method (GA-RSWAT), and an Effective Infiltration Capacity method (EIC-RSWAT). These four versions of RSWAT and a Daily Curve Number based original SWAT (DCN-SWAT) were applied to simulate daily stream flow and baseflow (from 2001 to 2015) at the Tuckahoe Creek Watershed (TCW) and Greensboro Watershed (GW) in Maryland, US. The global sensitivity analysis algorithms within SWAT-CUP was used to identify sensitive parameters, and the Sequential Uncertainty Fitting algorithm version 2 (SUFI-2) was used to analyze uncertainty for different models in both calibration and validation periods. Comparison of the results from different models highlight the sensitivity of watershed modeling to the differences between surface runoff and infiltration partition methods. In general, DCN-RSWAT outperformed other versions of RSWAT and the standard SWAT model with reduced daily flow rate perdition uncertainty and improved simulation of daily baseflow in both test watersheds. We anticipate the numerical experiments examined here will provide new insights into better practices in choosing surface runoff and infiltration partition methods for SWAT and other watershed models, thereby supporting sustainable water resources assessment and management.

Spatially Disaggregating Satellite Land Surface Temperature With a Nonlinear Model Across Agricultural Areas

AbstractAccurate remotely sensed land surface temperature (LST) is a promising tool for predicting surface evapotranspiration (ET). The spatial resolution of commonly existing daily satellite products (i.e., Moderate Resolution Imaging Spectroradiometer [MODIS] LST) is ~1 km, which remains relatively low for used in estimating ET. This paper developed a model that disaggregates ~1‐km spatial resolution MODIS‐derived LST data to fine spatial resolutions of 250 m. The proposed model was achieved by using a spatial and temporal nonlinear strategy that contains the predictor variables of the Bowen ratio, the photochemical reflectance index, and the normalized difference vegetation index. The proposed disaggregation model was assessed mainly at two agriculture sites, including the Heihe River Basin in China and the Walnut Creek Watershed in the United States, during the growing seasons. The assessment procedure was conducted at both the field scale and the image scale in terms of disaggregated LST and ET. The statistical results demonstrated that the proposed model produced 250‐m LST and ET that matched better with the observed values and achieved more accurate LST and ET relative to other reference ones. Our study shows that surface moisture status and vegetation physiological dynamic are important factors in improving the LST disaggregation over the agriculture region. The results of this study have the potential to improve water resource management and sustainable water use.

Residential Land Use Change in the Wissahickon Creek Watershed: Profitability and Sustainability?

The Wissahickon Creek Watershed is one of five major watersheds in the Philadelphia metro region. The main objective of the work in this paper was to determine and compare the energy and environmental impacts of placing housing in the Watershed according to profitability and environmental sustainability criteria, respectively, in the context of increasing urbanization. Future population and employment for the Watershed have been projected by the Delaware Valley Regional Planning Commission. Housing requirements for the projected populations in each municipality were computed, and their location was influenced by the local zoning ordinances. Suitability analysis using ArcGIS 10.6 generated areas for development based alternatively on profitability and local sustainability. CommunityViz 5.2 Scenario 360 software was used to place buildings within the appropriately-zoned areas. Using Argonne National Laboratory’s Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET1 2018) software and water quality monitoring information from the Philadelphia Water Department, impacts were directly estimated. The impacts were related to effects on ecosystem functioning, ecosystem goods and services, and broad value estimated for the latter. The effects were used to indicate what might be appropriate policies to reduce the negative environmental consequences of residential development in the watershed. Unexpectedly, the environmental impacts of the profitable and sustainable scenarios were not very different. This suggests that profitability and sustainability need not be mutually exclusive.

PFHydro: A New Watershed-Scale Model for Post-Fire Runoff Simulation

Runoff increases after wildfires that burn vegetation and create a condition of soil-water repellence (SWR). A new post-fire watershed hydrological model, PFHydro, was created to explicitly simulate vegetation interception and SWR effects for four burn severity categories: high, medium, low severity and unburned. The model was applied to simulate post-fire runoff from the Upper Cache Creek Watershed in California, USA. Nash–Sutcliffe modeling efficiency (NSE) was used to assess model performance. The NSE was 0.80 and 0.88 for pre-fire water years (WY) 2000 and 2015, respectively. NSE was 0.88 and 0.93 for WYs 2016 (first year post-fire) and 2017 respectively. The simulated percentage of surface runoff in total runoff of WY 2016 was about six times that of pre-fire WY 2000 and three times that of WY 2015. The modeling results suggest that SWR is an important factor for post-fire runoff generation. The model was successful at simulating SWR behavior.

Management Scale Assessment of Practices to Mitigate Cattle Microbial Water Quality Impairments of Coastal Waters

Coastal areas support multiple important resource uses including recreation, aquaculture, and agriculture. Unmanaged cattle access to stream corridors in grazed coastal watersheds can contaminate surface waters with fecal-derived microbial pollutants, posing risk to human health via activities such as swimming and shellfish consumption. Improved managerial control of cattle access to streams through implementation of grazing best management practices (BMPs) is a critical step in mitigating waterborne microbial pollution in grazed watersheds. This paper reports trend analysis of a 19-year dataset to assess long-term microbial water quality responses resulting from a program to implement 40 grazing BMPs within the Olema Creek Watershed, a primary tributary to Tomales Bay, USA. Stream corridor grazing BMPs implemented included: (1) Stream corridor fencing to eliminate/control cattle access, (2) hardened stream crossings for cattle movements across stream corridors, and (3) off stream drinking water systems for cattle. We found a statistically significant reduction in fecal coliform concentrations following the initial period of BMP implementation, with overall mean reductions exceeding 95% (1.28 log10)—consistent with 1—2 log10 (90–99%) reductions reported in other studies. Our results demonstrate the importance of prioritization of pollutant sources at the watershed scale to target BMP implementation for rapid water quality improvements and return on investment. Our findings support investments in grazing BMP implementation as an important component of policies and strategies to protect public health in grazed coastal watersheds.

Agricultural land use impacts microbial community structure of streambed sediments

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 83:225-236 (2019) - DOI: https://doi.org/10.3354/ame01905 Agricultural land use impacts microbial community structure of streambed sediments Caitlyn A. Griffith1, Peng Shang2, YueHan Lu2, Ethan J. Theuerkauf3, Antonio B. Rodriguez4, Robert H. Findlay1,* 1Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama 35401, USA 2Department of Geological Sciences, The University of Alabama, 201 7th Ave, Tuscaloosa, Alabama 35485, USA 3Illinois State Geological Survey, Prairie Research Institute, The University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA 4University of North Carolina, Institute of Marine Sciences, 3431 Arendell St, Morehead City, North Carolina 28557, USA *Corresponding author: rfindlay@ua.edu ABSTRACT: Agricultural land use is known to adversely affect freshwater ecosystems, and recent studies have shown that it can significantly alter dissolved organic matter (DOM) concentrations and quality. DOM quantity and quality are key determinants of microbial community structure in streams and have been linked to changes in community abundance and composition. Considering the vital ecological role sediment microbes play in stream ecosystems, it is important to understand how agricultural land use changes affect stream microbial community structure. This study was conducted to determine if variation in sediment microbial biomass community structure could be attributed to differences in agricultural land use. Microbial biomass, microbial community structure, and stream water parameters were compared on 2 dates from 6 sites representing a gradient of agricultural land use from 18 to 64% within the Bear Creek Watershed in northwest Alabama, USA. Total microbial biomass, determined as phospholipid phosphate, was strongly influenced by sediment surface area and, to a lesser extent, correlated with sampling date and land use. Sediment microbial community structure, determined by phospholipid fatty acid analysis, was significantly correlated to percent agricultural land use in the watershed, as well as stream water DOM humification index, and sediment δ15N values and surface area. Microbial community structure also differed between sampling dates. These findings demonstrate that agricultural land use is linked via alteration of stream water and sediment organic matter to changes in sediment microbial structure which may, at least in part, account for widely observed changes in stream ecosystem functioning associated with agricultural activities. KEY WORDS: Microbial community structure · Streams · Agricultural land use · DOM Full text in pdf format Supplementary material PreviousNextCite this article as: Griffith CA, Shang P, Lu Y, Theuerkauf EJ, Rodriguez AB, Findlay RH (2019) Agricultural land use impacts microbial community structure of streambed sediments. Aquat Microb Ecol 83:225-236. https://doi.org/10.3354/ame01905 Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in AME Vol. 83, No. 3. Online publication date: October 02, 2019 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2019 Inter-Research.

A novel approach for assessing watershed susceptibility using weighted overlay and analytical hierarchy process (AHP) methodology: a case study in Eagle Creek Watershed, USA

Watershed vulnerability and the characterization of potential risk are important inputs for decision support tools in assessing watershed health. Most previous studies have focused on the assessment of the environmental risk using physicochemical properties of surface water and mathematical models to predict the health of a watershed. Here, we present a new methodology for evaluating watershed vulnerability using the analytic hierarchy process (AHP) and weighted overlay analysis. The new methodology provides an inexpensive approach for assessing areas that need more investigation based on known factors such hydrogeological, geological, and climate parameters without the need for site-specific physicochemical data. The proposed method was implemented using six main factors that influence water quality: land use, soil type, precipitation, slope, depth to groundwater, and bedrock type. Vulnerability was predicted for ten sub-watersheds within the Eagle Creek Watershed in Indiana using publicly available data input into geographic information system. Combination of watershed susceptibility assessment and GIS spatial analysis tools was used to produce the maps that show the susceptible zones within a watershed. A comparison of the resulting vulnerability estimates showed the expected significant positive correlations with measurements of nitrate, phosphate, temperature, and electrical conductivity. Likewise, the vulnerability estimates negatively correlated with dissolved oxygen and E. coli. Furthermore, the validation of the proposed approach revealed that the areas predicted to have high vulnerability did have lower water quality indices; the results showed a high negative correlation (r2 = 0.77, p < 0.05) between water quality index (WQI) and vulnerability which strongly suggests this method can be used successfully to assess a watershed’s susceptibility.

Modelling the impacts of grassland to cropland conversion on river flow regimes in Skunk Creek watershed, Upper Midwest United States

AbstractConversion of grassland to cultivated cropland has been linked to downstream alteration of flow regimes. This study used the Soil and Water Assessment Tool (SWAT) to construct seven “what if” scenarios for quantifying the impacts of grassland to cropland and vice versa conversion (i.e., replacement of grassland with selected agricultural crops) on river flow regimes in Skunk Creek watershed. The Cropland Data Layer for the year 2011 in conjunction with historical climate data was used to create SWAT models for scenario simulations over 19 years, from 1996 to 2014. The model developed for the historical climate records (baseline) was compared with the scenarios examined using stream flow metrics for a range of flow regimes, including magnitude, duration, frequency, and timing of annual low‐ and high‐flow conditions. The simulation results suggest that grassland conversion to cultivated cropland would generally increase river flows compared with conversion of cultivated cropland to grassland, which may reduce flows in the watershed. Low and moderate flows increased by 2–8% from the baseline scenario with conversion of grass crop and by 1–20% decreases with crop–grass conversion. High flows increased by 3–7% and decreased by 1–18% when grass is converted to crop and crop to grass, respectively. The analysis also suggests that grassland establishment may attenuate the peaks of prolonged small floods and shorter but earlier large floods.

Field scale nitrogen load in surface runoff: Impacts of management practices and changing climate

The use of Nitrogen (N) fertilizer boosted crop production to accommodate 7 billion people on Earth in the 20th century but with the consequence of exacerbating N losses from agricultural landscapes. Land management practices that can prevent high N load are constantly being sought for mitigation and conservation purposes. This study was aimed at evaluating the impacts of different land management practices under projected climate scenarios on surface runoff linked N load at the field scale level. A framework to analyze changes in N load at a high spatiotemporal resolution under high greenhouse emission climate projections was developed using the Pesticide Root Zone Model (PRZM) for the Willow Creek Watershed in the Fort Cobb Experimental Watershed in Oklahoma. Specifically, 12 combinations of land management and climate scenarios were evaluated based on their N load via surface runoff from 2020 to 2070. Results showed that crop rotation practices lowered both the N load and the probability of high N load events. Spring application reduced the negative effects in summer and fall from other land management practices but at the risk of increased probability of generating high N load in April and May. The fertilizer application rate was found to be the most critical factor that affected the amount and the probability of high N load events. By adopting a target application management approach, the monthly maximum N can be decreased by 13% while the annual mean N load by 6%. The model framework and analysis method developed in this research can be used to analyze tradeoffs between environmental welfare and economic benefits of N fertilizer at the field scale level.

The Beargrass Story: Utilizing Social Science to Evaluate and Learn from the “Watershed Approach”

AbstractThis paper presents the case of a voluntary watershed project that addressed the need for improving water quality by reducing agricultural nutrient loss. The Beargrass Creek Watershed Approach Project in Wabash County, Indiana aimed to demonstrate that it is possible to achieve ambitious water quality goals and maximize the effectiveness of conservation funding through locally‐led efforts that bring together multiple stakeholders throughout the process. The project focused on implementing the “right practices” in the “right places” through a goal‐oriented, science‐based, and locally‐adapted approach to voluntary conservation. We examine and evaluate all three phases of the project and discuss successes and lessons learned from the point of view of both agricultural producers and agency staff from the local Soil and Water Conservation District and the Natural Resources Conservation Service.

Modelling historical and potential future climate impacts on Keremeos Creek, an Okanagan-Similkameen watershed, British Columbia, Canada: Part II. Forecasting change in farm-level greenhouse gas emissions

This manuscript, Part II of a climate change impacts assessment series, describes changes in CO2, CH4, and N2O emissions and soil carbon storage on a theoretical farm in the Keremeos Creek watershed under scenarios of historical and potential climate using Holos v3.0.3 greenhouse gas (GHG) emissions model. The GENerate Earth SYstems Science input (GENESYS) spatial hydro-meteorological model outputs from Part I, which represent future hydro-meteorological conditions in the watershed under the ensemble averages of 15 General Circulation Models (GCMs) for two Representative Concentration Pathways (RCP) scenarios (RCP 4.5 and RCP 8.5) and three time periods (2011–2040, 2041–2070, and 2071–2100) relative to the 1961–1990 base period, are adapted to provide Holos v3.0.3 inputs. Adapting the GENESYS output facilitated Holos v3.0.3 modelling of farm GHG emissions to determine whether the simulated farm with both beef and crop production becomes a carbon sink, or source. The result demonstrated that there may be reductions in emissions related to enteric CH4, manure CH4, manure direct N2O, and indirect N2O for different climate change scenarios and time periods. However, there may also be increases in crop direct N2O and energy use CO2 for the same scenarios. Furthermore, soil carbon storage under fruit tree orchards is expected to increase. According to this result, the simulated farm in the Keremeos Creek watershed is a carbon sink and the carbon capture projects an increase to higher levels, depending on different climate change scenarios and time periods. However, if the simulation is conducted without fruit tree orchards as a carbon sink, the simulated farm in the Keremeos Creek watershed is a carbon source and the carbon emissions will increase for different climate change scenarios and time periods. These results demonstrate the importance of woody crops as a mitigation option for reducing farm-level GHG emissions in future.

Assessing and mitigating the effects of agricultural soil erosion on roadside ditches

PURPOSE: Roadside ditches line more than 6.3 million km of roadways in the USA, dissecting the natural topography and altering the flow of runoff from the catchments that drain into them. In agricultural regions, more than 30% of a watershed may directly drain into the roadside ditch system. Quantifying soil erosion and sediment export from agricultural watersheds is a crucial component when considering long-term soil sustainability. MATERIALS AND METHODS: Our study evaluated the relation of catchment soil erosion and ditch sedimentation at six representative roadside ditches in Lime Creek watershed (eastern Iowa) and quantified the effectiveness of possible catchment conservation practices to reduce soil erosion and ditch sedimentation. RESULTS AND DISCUSSION: Study results provide clear evidence linking roadside ditches to the agricultural catchments that drain into them. Among the six ditch sites, catchment erosion was found to be inversely related to sediment storage within the ditch due to erosive power of water entering the ditches from their basins. Of four catchment scenarios to reduce soil erosion, no-till with cover and graded terrace did not require land to be taken out of production and provided the most significant reductions in catchment erosion rates. CONCLUSIONS: Results indicated that reducing nutrient and sediment loads to ditches by incorporating in-field conservation practices in ditch catchments may be more economical and environmentally sustainable than current management practices for both farmers and roadway managers because they trap detached soil sediments before they enter the ditch.

If They Come, Where will We Build It? Land-Use Implications of Two Forest Conservation Policies in the Deep Creek Watershed

Research Highlights: Forest conservation policies can drive land-use change to other land-use types. In multifunctional landscapes, forest conservation policies will therefore impact on other functions delivered by the landscape. Finding the best pattern of land use requires considering these interactions. Background and Objectives: Population growth continues to drive the development of land for urban purposes. Consequently, there is a loss of other land uses, such as agriculture and forested lands. Efforts to conserve one type of land use will drive more change onto other land uses. Absent effective collaboration among affected communities and relevant institutional agents, unexpected and undesirable land-use change may occur. Materials and Methods: A CLUE-S (Conversion of Land Use and its Effects at Small Scales) model was developed for the Deep Creek watershed, a small sub-basin in the Okanagan Valley of British Columbia, Canada. The valley is experiencing among the most rapid population growth of any region in Canada. Land uses were aggregated into one forested land-use type, one urban land-use type, and three agricultural types. Land-use change was simulated for combinations of two forest conservation policies. Changes are categorized by location, land type, and an existing agricultural land policy. Results: Forest conservation policies drive land conversion onto agricultural land and may increase the loss of low elevation forested land. Model results show where the greatest pressure for removing land from agriculture is likely to occur for each scenario. As an important corridor for species movement, the loss of low elevation forest land may have serious impacts on habitat connectivity. Conclusions: Forest conservation policies that do not account for feedbacks can have unintended consequences, such as increasing conversion pressures on other valued land uses. To avoid surprises, land-use planners and policy makers need to consider these interactions. Models such as CLUE-S can help identify these spatial impacts.

Patterns of legacy sediment deposits in a small South Carolina Piedmont catchment, USA

Anthropogeomorphic changes to channels and floodplains occurred in response to destructive agricultural practices following the arrival of European settlers into the Americas. The southeastern Piedmont physiographic region of the USA experienced severe erosion and sedimentation after settlement in the 1700s and farming up through the 1930s. In places, deep floodplain aggradation formed uninterrupted alluvial deposits that extend many kilometers. This research examines anthropogenic impacts of land-use change on valley bottom sedimentation in the Chicken Creek Watershed of South Carolina. Abrupt contacts between precolonial floodplain soils and a thick overburden of historical legacy sediment are common and well exposed throughout the two-km study reach and provide clear evidence of extensive postcolonial sedimentation. Soil stratigraphic and sedimentologic evidence are presented to identify and contrast pre- and postcolonial sediment characteristics and thicknesses. LiDAR-based spatial analysis is used to examine patterns of legacy sediment deposition and floodplain storage and—together with field observations of bank stratigraphy—examine the environments in which this occurred. Precolonial geomorphic stability is indicated by a buried soil epipedon (Ab horizon) and other features on precolonial floodplain surfaces.Legacy sediment 2 to 4 m thick rests on top of exposed precolonial soils throughout the stream corridor, with the pre−/postcolonial contact ~1.5 m above the channel bed on average. Linear regression analysis shows that legacy sediment thickness varies statistically with changes in valley width and proximity to tributary sediment sources. Thin precolonial alluvium over bedrock suggests modest erosion and sedimentation rates prior to the arrival of EuroAmerican settlers. Mean grain-sizes are similar between the pre- and postcolonial alluvium, but substantial contrasts in the degree of stratification and bulk density document differences between the respective depositional environments and post-depositional changes to the two units. Channel adjustments since the time of maximum aggradation include bed incision to at least as low as the precolonial longitudinal profile and widening that is ongoing.

Post‐wildfire sediment cascades: A modeling framework linking debris flow generation and network‐scale sediment routing

AbstractWildfires represent one of the largest disturbances in watersheds of the Intermountain West. Yet, we lack models capable of predicting post‐wildfire impacts on downstream ecosystems and infrastructure. Here we present a novel modeling framework that links new and existing models to simulate the post‐wildfire sediment cascade, including spatially explicit predictions of debris flows, storage of debris flow sediment within valleys, delivery of debris flow sediment to active channels, and the downstream routing of sediment through river networks. We apply the model to sediment dynamics in Clear Creek watershed following the 2010 Twitchell Canyon Fire in the Tushar Mountains of southern Utah. The debris flow generation model performed well, correctly predicting 19 out of 20 debris flows from the largest catchments, with only four false positives and two false negatives at observed rainfall intensities. In total, the model predicts the occurrence of 160 post‐wildfire debris flows across the Clear Creek watershed, generating more than 650 000 m3 of sediment. Our new storage and delivery model predicts the vast majority of this sediment is stored within valleys, and only 13% is delivered to the river network. The sediment routing model identifies numerous sediment bottlenecks within the network, which alter transport dynamics and may be hotspots for aggradation and aquatic habitat alteration. The volume of sediment exported from the watershed after seven years of simulation totals 17% of that delivered, or 2% of the total generated debris flow sediment. In the case of the Twitchell Canyon Fire, this highlights that significant post‐wildfire sediment volumes can be stored in valleys (87%) and within the stream network (11%). Finally, we discuss useful insights that can be gleaned from the model framework, as well as the limitations and need for more monitoring and theory development in order to better constrain essential inputs, process rates, and morphodynamics. © 2019 John Wiley &amp; Sons, Ltd.

Repurposing Environmental DNA Samples to Verify the Distribution of Rocky Mountain Tailed Frogs in the Warm Springs Creek Basin, Montana

Rocky Mountain tailed frogs (Ascaphus montanus) were thought to exist exclusively in two tributaries of Warm Springs Creek watershed—Storm Lake Creek and Twin Lakes Creek, based on opportunistic observations of tailed frogs during fish sampling rather than formal basin-wide sampling for frogs. We used extant environmental DNA (eDNA) samples originally collected to delineate bull trout (Savelinus confluentus) occupancy to determine whether tailed frogs reside outside of their current known distribution in the Warm Springs Creek watershed. We were able to rapidly confirm tailed frog occupancy in these two tributaries of Warm Springs Creek watershed, and located tailed frogs throughout the mainstem of Warm Springs Creek where their presence was previously unknown. Repurposing eDNA samples provides a sensitive and extremely cost effective way to determine species distributions, because existing samples can continue to be retested for unrelated taxa without repeating field collections.

Modeling effectiveness of broiler litter application method for reducing phosphorus and nitrogen losses

Abstract The linkages among the best management practices implemented at the field level and downstream water quality improvement at the watershed level are complex, because the processes that link management practices and watershed-level water quality span a range of scales. However, it is important to understand the effect of nutrient management strategies on watershed-level water quality because most of the water quality evaluation occurs at the watershed scale. The overall goal of this study was to quantify the effect of broiler litter application method (surface vs. subsurface application) on phosphorus (P) and nitrogen (N) losses in surface runoff using the Soil and Water Assessment Tool (SWAT) model. The research was conducted in the Big Creek watershed (8,024 ha) located in Mobile County, Alabama, USA. At the hydrological response unit level, the subsurface application of broiler litter to pastures reduced average annual (1991–2015) total P and N losses in surface runoff by 72% and 33%, respectively, compared to surface application of broiler litter. At the watershed outlet, subsurface application of broiler litter to pastures (covered 43% of the watershed area after the land use change scenario) reduced average annual (1991–2015) total P and N losses by 39% and 20%, respectively.

Evaluation of Nitric Acid Extraction of Elements from Soils and Sediments in Two watersheds in East Tennessee

ABSTRACTDetermining the total elemental concentrations of soils requires a total dissolution method, in which hydrofluoric acid (HF) is commonly used. However, this method is tedious and risky due to the dangerous reagent HF. This study compared a single acid extraction technique using a nitric acid (HNO3) extraction method to total dissolution (HF + microwave assisted aqua regia) for evaluating the total elemental concentrations in soils and sediments. The two methods were used to analyze the elemental content of soils and sediments from the Oostanaula Creek and Pond Creek watersheds in East Tennessee. Twenty-one elements (Al, Ba, Ca, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Nd, P, S, Si, Sr, Ti, V, Zn, and Zr) were subsequently measured using inductively coupled plasma optical emission spectrometry (ICP-OES). The extraction efficiency for HNO3 relative to the total was compared and discussed. In general, HNO3 can extract the elements in absorbed phases and those residing in non-silicate minerals. Six elements (Ba, Co, Fe, Ca, Mn, and P) generated significant correlations between total and HNO3 in both OC and PC watersheds. Finally, the elements were grouped according to the interrelationships of their total elemental concentrations based on the dendrogram plots, suggesting their geochemical association in soils and sediment forming minerals.

Documentation of Freshwater Mussels (Unionidae) in the Diet of Round Gobies (Neogobius melanostomus) within the French Creek Watershed, Pennsylvania

The round goby (Neogobius melanostomus) was discovered in 2013 in the French Creek (Allegheny River Drainage) watershed and is the first documented invasion outside of the Lake Erie basin in Pennsylvania. The round goby throughout the Laurentian Great Lakes is known to eat dressenid mussels (Dreissenidae), but consumption of either dressenids or native mussels (Unionidae) in tributaries to Lake Erie is minimal based on low populations of any bivalves. The French Creek watershed, on the other hand, harbors 29 species of native freshwater mussels as well as introduced fingernail clams (Sphaeriidae; Corbicula fluminea). The objectives of this study were to document the diet of round gobies in the French Creek watershed to determine whether consumption of native freshwater mussels was occurring. Round gobies were collected in the summer months (May–Sept.) of 2016 via kick seine in four locations, dissected, and their stomach contents identified to lowest possible taxa. We separated the gobies into categories based on length classes, in order to determine if diet changed with increased size and age. Unionid mussels were consumed by all length classes, particularly in length class one (30–44 mm), but diet shifted to a dominance of sphaeriids in length class four (≥75 mm). Round gobies also consumed benthic aquatic insects, a large percentage of which were chironomids (greater than 24% in all size classes). This is the first documentation of unionid consumption by the round goby in Pennsylvania that poses possible threats to native mussels in the French Creek watershed.

Production of sediment from the running surface of unpaved legacy roads in southeast Ohio, USA

ABSTRACTUnpaved, or unbound aggregate, roads are thought to be one of the largest anthropogenic sources of fine sediments in the stream channels of small watersheds. Sedimentation can reduce water quality in streams negatively impacting aquatic habitat as well as being a detriment to municipal drinking water sources. Even during periods of low-volume use roads can be a chronic source of fine sediment. Legacy roads may degrade stream water quality more than newly built roads as they were constructed before modern best management practices. This study measured the production of sediment from the road surface of a legacy road system within a small watershed using controlled precipitation experiments to determine the mass of sediment that roads could produce during one storm event. Sediment production was not related to road slope or strength as measured by Clegg hammer. The production of sediment from the road surface increased 95% on average with wet traffic use. Using an estimated road and stream connectivity of 50%, surface runoff from the roads in Middle Creek watershed could account for 16% of the total sediment yield from the watershed during a small summer storm event. Compacted tire tracks were utilized as flow paths during runoff experiments, emphasizing the importance of continual maintenance and best management practices. This study highlights the need to disconnect unbound aggregate roads from stream channels in order to prevent negative water quality impacts associated with sedimentation.