Quantifying stream phosphorus dynamics and total suspended sediment export in forested watersheds in Vermont

Globally the quantity of reactive phosphorus (P) in soils, streams and groundwater has greatly increased throughout the 20th and early 21st centuries. This phenomenon is problematic in Vermont, evidenced by the repeated cyanobacteria blooms in shallow bays in Lake Champlain. While many studies have focused on P dynamics in agricultural watersheds, there is limited information on P dynamics in forested watersheds. Current remediation plans under the Lake Champlain total maximum daily loads (TMDL) call for substantial reductions in P loadings from forested areas of the basin. However, the lack of information and knowledge regarding forest P dynamics limits management and remediation plans. This study was conducted in three small forested watersheds, ranging in size from 2.5 to 8.3 square kilometers that have been managed under varying practices, including logging and maple sugaring. All three watersheds drain into Missisquoi Bay, a shallow bay in Lake Champlain that consistently has seasonal algal blooms. Streams in the forested watersheds were instrumented with turbidity sensors and pressure transducers to measure stage. A rating curve was developed during field visits to relate stage to discharge. Water samples were collected from May through November 2017 using ISCO Automated Samplers. A total of twenty storm events were captured, along with periodic baseflow sampling, and these data were used to characterize P concentrations and calculate seasonal P loadings. Results indicate that there is a strong positive relationship between turbidity, total suspended sediment and total phosphorus concentrations (R2 ranging from 0.64 to 0.83). The results of this project provide insight into transport of P and total suspended sediment within forested catchments of Lake Champlain tributaries. In particular, the research shows that fluxes in total phosphorus are linked to fluxes in total suspended sediment and that the overall monthly totals of P being exported from forested catchments are low, relative to urban, suburban and agricultural areas

Effects of different soil media, vegetation, and hydrologic treatments on nutrient and sediment removal in roadside bioretention systems

Water quality performance of eight roadside bioretention cells in their third and fourth years of implementation were evaluated in Burlington, Vermont. Bioretention cells received varying treatments: (1) vegetation with high-diversity (7 species) and low-diversity plant mix (2 species); (2) proprietary SorbtiveMedia™ (SM) containing iron and aluminum oxide granules to enhance sorption capacity for phosphorus; and (3) enhanced rainfall and runoff (RR) to certain cells (including one with SM treatment) at three levels (15%, 20%, 60% more than their control counterparts), mimicking anticipated precipitation increases associated with climate change. A total of 121 storms across all cells were evaluated in 2015 and 2016 for total suspended solids (TSS), nitrate/nitrite-nitrogen (NOx), ortho-phosphorus (Ortho-P), total nitrogen (TN) and total phosphorus (TP). Heavy metals were also measured for a few storms, but in 2014 and 2015 only. Simultaneous measurements of flow rates and volumes allowed for evaluation of the cells’ hydraulic performances and estimation of pollutant load removal efficiencies and EMC reductions. Significant average reductions in effluent stormwater volumes (75%; range: 48–96%) and peak flows (91%; range: 86–96%) was reported, with 31% of the storms events (all less than 25.4 mm (1 in.), and one 39.4 mm (1.55 in.)) depth completely captured by bioretention cells. Influent TSS concentrations and event mean concentrations (EMCs) was mostly significantly reduced, and TSS loads were well retained by all bioretention cells (94%; range: 89–99%) irrespective of treatments, storm characteristics or seasonality. In contrast, nutrient removal was treatment-dependent, where the SM treatments consistently removed P concentrations, loads and EMCs, and sometimes N as well. The vegetation and RR treatments mostly exported nutrients to the effluent for those three metrics with varying significance. We attribute observed nutrient exports to the presence of excess compost in the soil media. Rainfall depth and peak inflow rate had consistently negative effects on all nutrient removal efficiencies from the bioretention cells likely by increasing pollutant mobilization. Seasonality followed by soil media presence, and antecedent dry period were other predictors significantly influencing removal efficiencies for some nutrient types. Results from the analysis will be useful to make bioretention designers aware of the hydrologic and other design factors that will be the most critical to the performance of the bioretention systems in response to interactive effects of climate change

The use of CMIP5 data to simulate climate change impacts on flow regime within the Lake Champlain Basin

Study region: Lake Champlain Basin, northwestern New England, USA. Study focus: Our study uses regional hydrologic analyses and modeling to examine alternative possibilities that might emerge in the Lake Champlain Basin streamflow regime for various climate scenarios. Climate data as well as spatial data were processed to calibrate the Regional Hydro-Ecological Simulation System (RHESSys) model runoff simulations. The 21st century runoff simulations were obtained by driving the RHESSys model with climate data from the Coupled Model Intercomparison Project phase 5 (CMIP5) for representative concentration pathways RCP 4.5 and 8.5. New hydrological insights for the region: Our analyses suggest that most of CMIP5 ensembles fail to capture both the trends and variability observed in historical precipitation when run in hindcast. This raises concerns of using such products in driving hydrologic models for the purpose of obtaining reliable runoff projections that can aid researchers in regional planning. A subset of five climate models among the CMIP5 ensembles have shown statistically significant trends in precipitation, but the magnitude of these trends is not adequately representative of those seen in observed annual precipitation. Adjusted precipitation forecasts project a streamflow regime described by an increase of about 30% in seven-day maximum flow, a four days increase in flooded days, a three orders of magnitude increase in base flow index, and a 60% increase in runoff predictability (Colwell index)

Design of a Gas Test Loop Facility for the Advanced Test Reactor

The Office of Nuclear Energy within the U.S. Department of Energy (DOE-NE) has identified the need for irradiation testing of nuclear fuels and materials, primarily in support of the Generation IV (Gen-IV) and Advanced Fuel Cycle Initiative (AFCI) programs. These fuel development programs require a unique environment to test and qualify potential reactor fuel forms. This environment should combine a high fast neutron flux with a hard neutron spectrum and high irradiation temperature. An effort is presently underway at the Idaho National Laboratory (INL) to modify a large flux trap in the Advanced Test Reactor (ATR) to accommodate such a test facility [1,2]. The Gas Test Loop (GTL) Project Conceptual Design was initiated to determine basic feasibility of designing, constructing, and installing in a host irradiation facility, an experimental vehicle that can replicate with reasonable fidelity the fast-flux test environment needed for fuels and materials irradiation testing for advanced reactor concepts. Such a capability will be needed if programs such as the AFCI, Gen-IV, the Next Generation Nuclear Plant (NGNP), and space nuclear propulsion are to meet development objectives and schedules. These programs are beginning some irradiations now, but many call for fast flux testing within this decade

Investigations of runoff production and sedimentation on forest roads

Forest roads constructed in steep mountain landscapes have been associated with a number of effects on hydrologic and geomorphic processes. This research examined the effects of forest roads on the flow of water and sediment in drainage basins in the Cascade range of western Oregon. A study conducted at the hillslope scale (< 0.1 km²) during the 1996 water year examined the factors controlling runoff production on forest roads. Runoff response was related to climatic conditions (storm size and soil moisture) and to the hillslope setting (size of the contributing hillslope, hillslope gradient, and soil depth on contributing hillslopes) on which roads were located. These observations were consistent with a theoretical model of runoff production on steep hillslopes. A study conducted at the large basin scale (181 km²) examined erosion associated with forest roads during the February 1996 flood. Roads functioned both as initiation sites for erosion and as depositional sites, interrupting the flow of water and sediment along hillslopes and in channels. Roads constructed prior to 1960 in midslope and valley floor positions experienced the highest frequency of erosion and deposition, and these impacts were concentrated at elevations below 800 m, where storm precipitation was augmented by snowmelt. Both fluvial and mass wasting processes deposited sediment on roads and eroded sediment from roads, and multiple processes were linked in complex cascades at many sites. Roads were a net source of sediment in the basins studied, although they functioned as both sources and storage sites for sediment, depending upon their location on hillslopes. The results point to the importance of roads in both modifying physical processes and in routing material through drainage basins. The findings have significant implications for the management of roads in forested landscapes

Hydrologic integration of forest roads with stream networks in two basins, western Cascades, Oregon

This study assessed how logging-access roads may have contributed to observed historical increases in peak discharges associated with small and large logged basins in the western Cascades of Oregon. The study was conducted on the Lookout Creek (62km²) and the upper Blue River (118km²) basins. Potential road effects on hydrology were examined using a combination of field surveys and spatial modeling with a geographic information system (GIS). Road networks were similar in both basins with respect to hillslope position, orientation, and stream crossings, but roads in Blue River were constructed one or two decades later than roads in Lookout Creek. A total of 20% (62 km) of the road length was sampled to assess routing of surface flow, using 31 2-km transects stratified by decade of construction and hillslope position. Along each transect, ditches and culvert outlets were examined and this information used to predict the probable routing of water to (1) existing stream channels, (2) newly eroded gullies downslope of culvert outlets, or (3) subsurface flow. Nearly 60% of the surveyed road length appeared to route water directly to stream channels or into gullies. Over time, the length of road connected to stream crossings has decreased, while the length of road discharging runoff that reinfiltrates to subsurface flow has increased, as roads have progressed up hillslopes and onto ridges in Lookout Creek and Blue River. The relatively constant proportion of the road network draining to gullies over time suggests that roads have the potential to become integrated into stream networks, even when constructed on unchannelled hillslope positions. An extended stream network, assumed to exist under storm conditions, was simulated for the basins using a digital elevation model. Although gullies and ditches differ from natural channels, extrapolation of field surveys using the GIS suggested that roads might extend the stream network by as much as 40% during storm events. It is hypothesized that such an effect could decrease the time of concentration of stormflow and contribute to higher peak discharges observed after clearcutting and road construction in these basins. Differences in the magnitude of road effects on peak flow generation may occur among road systems according to hillslope position of roads, road age, soil saturation, geologic substrate, and climate. These differences may explain the range of observed results from paired-basin studies examining road effects on hydrologic response

SHG microscopic observations of polar state in Li-doped KTaO3 under electric field

Incipient ferroelectric KTaO3 with off-center Li impurity of the critical concentration of 2.8 mol% was investigated in order to clarify the dipole glass state under electric field. Using optical second-harmonic generation (SHG) microscope, we observed a marked history dependence of SHG intensity through zero-field cooling (ZFC), zero-field heating (ZFH), field heating after ZFC (FH/ZFC) and FH after field cooling (FH/FC). These show different paths with respect to temperature: In the ZFC/ZFH process, weak SHG was observed at low temperature, while in the FH/ZFC process, relatively high SHG appears in a limited temperature range below TF depending on the field strength, and in the FC and FH/FC processes, the SHG exhibits ferroelectric-like temperature dependence: it appears at the freezing temperature of 50K, increases with decreasing temperature and has a tendency of saturation. These experimental results strongly suggest that dipole glass state or polar nano-clusters which gradually freezes with decreasing temperature is transformed into semi-macroscopic polar state under the electric field. However at sufficiently low temperature, the freezing is so strong that the electric field cannot enlarge the polar clusters. These experimental results show that the polar nano-cluster model similar to relaxors would be more relevant in KTaO3 doped with the critical concentration of Li. Further experiments on the anisotropy of SHG determine that the average symmetry of the field-induced polar phase is tetragonal 4mm or 4, which is also confirmed by the X-ray diffraction measurement.Comment: 26 pages, 8 figures, 1 tabl

Identifying the spatial pattern and importance of hydro-geomorphic drainage impairments on unpaved roads in the northeastern USA

Roads have been widely studied as sources of runoff and sediment and identified as pollutant production sources to receiving waters. Despite the wealth of research on logging roads in forested, upland settings, little work has been conducted to examine the role of extensive networks of rural, low-volume, unpaved roads on water quality degradation at the catchment scale. We studied a network of municipal unpaved roads in the northeastern US to identify the type and spatial extent of ‘hydro-geomorphic impairments’ to water quality. We mapped erosional and depositional features on roads to develop an estimate of pollutant production. We also mapped the type and location of design interventions or best management practices (BMPs) used to improve road drainage and mitigate water quality impairment. We used statistical analyses to identify key controls on the frequency and magnitude of erosional features on the road network, and GIS to scale up from the survey results to the catchment scale to identify the likely importance of unpaved roads as a pollutant source in this setting. An average of 21 hydro-geomorphic impairments were mapped per kilometer of road, averaging 0.3 m3 in volume. Road gradient and slope position were key controls on the occurrence of these features. The presence of BMPs effectively reduced erosion frequency. Scaled up to the watershed and using a conservative estimate of road–stream connectivity, our results for the Winooski River watershed in the northeastern US suggest that roughly 16% and 6% of the average annual sediment and phosphorus flux, respectively, of the Winooski River may be derived from unpaved roads. Our study identifies an under-appreciated source of water quality degradation in rural watersheds, provides insights into identifying ‘hot spots’ of pollutant production associated with these networks, and points to effectiveness of design interventions in mitigating these adverse impacts on water quality. Copyright © 2017 John Wiley & Sons, Ltd

Drill pipe protector development

The Geothermal Drilling Organization (GDO), formed in the early 1980s by the geothermal industry and the U.S. Department of Energy (DOE) Geothermal Division, sponsors specific development projects to advance the technologies used in geothermal exploration, drilling, and production phases. Individual GDO member companies can choose to participate in specific projects that are most beneficial to their industry segment. Sandia National Laboratories is the technical interface and contracting office for the DOE in these projects. Typical projects sponsored in the past have included a high temperature borehole televiewer, drill bits, muds/polymers, rotary head seals, and this project for drill pipe protectors. This report documents the development work of Regal International for high temperature geothermal pipe protectors

Microwave Spectroscopy

Contains research objectives and reports on two research projects.U.S. Army Signal Corps under Contract DA36-039-sc-87376Lincoln Laboratory, Purchase Order DDL B-00306U. S. ArmyU. S. NavyU. S. Air Force under Air Force Contract AF19(604)-740