ALBERT

Description: Relationships among suspended sediment, phosphorus, and discharge vary temporally and spatially in the Lake Whatcom watershed, a 125-km 2 , high-relief, moderately developed, forested basin in northwestern Washington State. The lake is subject to a Total Maximum Daily Load to limit phosphorus inputs. Phosphorus, which largely enters the lake adsorbed to suspended sediment in streams, has led to increased algae growth and depletion of dissolved oxygen. We used the results of high-resolution storm event sediment and phosphorous sampling in five streams to examine the effects of varying watershed features on loading and to develop sediment-discharge and phosphorus-discharge models to estimate phosphorus loading to the lake during the 2013 water year. During most storm events, the sediment peak preceded the discharge peak. The magnitude of hydrograph rise was the best predictor of the maximum sediment concentration during the event. Of the five basins studied, a large, forested watershed that contains steep slopes susceptible to mass wasting yielded the most sediment per area. The highest phosphorus yield was from a smaller, lower-relief watershed containing 29 percent residential development. Our sediment and phosphorous yields were comparable to estimates from similar streams in the Puget Sound region in northwest Washington State. Total suspended solids and total phosphorus were significantly correlated to discharge in most streams in the watershed, but variability within and among storm events resulted in uncertainty when calculating fluxes based on discharge.

Description: Igneous intrusions are distributed extensively in the Huaibei coalfield, China. In the Haizi coal mine, coal and gas outbursts have occurred 11 times under an extremely thick sill (average thickness 120 m). This paper presents the results of a study on the influences of the igneous rock on coal pore structure, methane desorption and diffusion properties, and coal seam gas occurrence. The results show that the thermal evolution effect of the igneous sill prominently increases the specific surface area and pore volume of the affected coal. Samples HZ1 and HZ2 (No. 7 and No. 9 seams, respectively) closer to the sill possess improved pore connectivity, while samples HZ3 and HZ4 (away from the sill) and sample HZ5 (without sill covering) of the No. 10 coal seam have poor pore connectivity. Moreover, the effective diffusivity and desorption indexes of the coal increase progressively closer to the sill. The thermal effect of the igneous sill promotes the development of coal pores, thus leading to better pore connectivity, more desorbed gas, and much higher gas desorption and diffusion rates. Consequently, the thermal evolution effect of the igneous sill can change the occurrence and characteristics of the entrapment effect in the underlying coal seams, thus resulting in a high probability of gas hazards or even coal and gas outbursts in the coal seam close to the igneous sill. Engineering practices show that the affected coal seams have high gas content, gas pressure, and gas emission amounts as well as a high propensity for coal and gas outburst.

Description: Based on an assessment of rock scour at 15 bridges across West Virginia, a risk-based screening strategy is proposed that accounts for both mode of scour and stream power. The proposed strategy is a result of research conducted to 1) characterize the hydraulic scour of rock at representative bridge sites in West Virginia with varying geological and hydrologic conditions; 2) assess the applicability of rock scour prediction techniques from National Cooperative Research Program (NCHRP) Report 717 to the types of rock and scour conditions at the bridge locations; and 3) identify strategies to better characterize scour of rock at bridge locations. Steps in the research included bridge-site selection; field inspection; determination of scour mode (i.e., quarrying/plucking or abrasion) and magnitude; rock core sampling; laboratory testing; and hydrologic and hydraulic evaluation and modeling. The abrasion-scour-mode test described in NCHRP 717 for degradable rock that erodes gradually over time was applied. However, all but one bridge site in the West Virginia study included durable, fractured rock that eroded by quarrying/plucking of rock blocks. Based on the results of this study, a risk-based screening strategy is proposed for bridges potentially affected by rock scour. This screening strategy includes three tiers: Tier I shows evidence of long-term channel stability and requires no further action in assessing rock scour; Tier II requires consideration of abrasion as the only mode of scour; and Tier III requires consideration of quarrying/plucking as the primary or significant secondary mode of scour.

Description: In the past years, lineament analysis has become an important analytical technique for delineation of major structural units in mineral prospecting, hydrogeology, and tectonic studies. The use of remote sensing, with progressive development of image enhancement techniques, provides an opportunity to produce more reliable and comprehensive lineament maps. In this paper, we propose the application of a semi-automatic approach based on digital terrain models (DTMs) for the extraction of potential lineaments and their detailed validation. We selected an area belonging to the Bagni di Vinadio municipality (Cuneo, NW Italy), which is part of the Argentera Massif (western Alps), as a test site. Data obtained from the code CurvaTool, developed by the authors, are successfully compared with literature information and with lineaments obtained from visual interpretation of remote sensing imagery. The CurvaTool code permits the extraction and classification of a greater number of linear features compared to visual interpretation techniques. The ability to detect features that are not perceptible by visual observation is a strong point of CurvaTool processing. In the test area, CurvaTool output data correlate with visually detected linear features and show a good correlation with regional tectonics and iso-kinematic maps from the literature.

Description: Post–dam removal geomorphologic adjustment of a stream channel has been documented in the scientific literature at watershed, hillslope, and laboratory scales. Hillslope-scale studies in channel cross sections are most common and add significant value in the dam-removal literature. This study examines geomorphic stream channel adjustment following dam removal at the hillslope scale under natural climatic conditions. A sediment-filled silt fence dam (1 m tall, 12.65 m wide) was removed in three stages, and the width and depth of the upstream developing channel was monitored at six transects for 15 months. Headcut retreat and changes in channel sinuosity were also recorded. After the silt fence dam was removed, channel development was initiated by headcut formation, which migrated upstream at a rate of 4 cm/d for about 10 months and then gradually reached attenuation. The channel progressed through four distinct stages: Stage 1 (Initial conditions); Stage 2 (Downcutting)—wide, shallow, meandering channel incised to a maximum depth of 0.52 m, and sinuosity decreased; Stage 3 (Floodplain development)—upon reaching base level, surface runoff began to meander within the channel, widening it through bank slumps and erosion; and Stage 4 (Quasi-equilibrium)—channel development reached dynamic (quasi-) equilibrium with only minor widening at downstream transects (maximum width of the incised channel reached 0.46 m), accompanied by sediment aggradation. The stages of upstream channel development and headcut retreat pattern in this study are consistent with the findings of other studies at the laboratory and watershed scales, indicating that channel development after dam removal is scale independent.

Description: Transportation corridor slopes have the potential to be hazardous to adjacent assets. The Rockfall Hazard Rating System (RHRS) is a stepwise process designed to identify potentially hazardous slopes by assigning a hazard rating that determines the order by which to mitigate and remediate slopes. The traditional RHRS approach is field-based: observations are made by a field crew who convert observations into slope ratings (preliminary and detailed). The purpose of this study is to examine the benefits of utilizing remote sensing techniques on 14 slopes within a 24-km railroad corridor in southeastern Nevada. Remote sensing allows for data acquisition in difficult-to-reach locations from various view angles. Images and data from three remote sensing technique-platform combinations are examined: optical imagery acquired via satellite, unmanned aerial vehicle, and LiDAR data acquired from a stationary sensor. Detailed RHRS slope ratings from both sets of optical images are compared to two types of field-based ratings: (1) initial field observations performed using the traditional RHRS approach and (2) average detailed rating scores from six participants (geologists and geotechnical engineers) given field notes of the 10 rating criteria for the 14 slopes. Terrestrial LiDAR is capable of monitoring slow slope deformation, with an accuracy of approximately 2 cm/yr, and identifying areas of rapid deformation. Remote sensing techniques should not entirely replace traditional field methods. Instead, developing an approach that combines the advantages of field- and remote sensing – based methodologies will enable transportation agencies to ensure a more robust, efficient, and time-effective RHRS approach.

Description: The Melen Dam is under construction to support the water supply to the Istanbul Metropolitan area. Karstified limestone, which forms the major aquifer in the region, crops out at the left bank of the reservoir and extends to the adjacent basin, where it is drained by two main springs. An area of 20 ha that is covered by this limestone is planned to be lined by concrete mass cover. Another spring that discharges within this lining area will be plugged by the concrete mass. As a consequence of uplift pressure, piezometric pressure is expected to build up underneath the concrete lining. Prediction and relief of the uplift pressure are of utmost importance in optimizing the concrete lining. This was achieved by performing a numerical simulation of the uplift pressure of the pre-lining and post-lining conditions at the site. This required development of a representative hydrogeological conceptual model as the very first stage of this study. The conceptual model was then transferred to a numerical model through the software Seep/w of GeoStudio (2007 version). The optimal design of the concrete lining was developed after performing a number of numerical simulations on the calibrated model. The model suggested that the uplift pressure would be relieved to an acceptable level by construction of drains underneath the concrete slabs at certain locations.

Description: Successful control measures require proper design, maintenance, and monitoring to evaluate effectiveness. To study stormwater runoff mitigation techniques, a row of infiltration trenches with different designs was monitored for 2.5 years. The three trench designs included gravel-filled, gravel-filled with a leaf filter, and sand-filled trenches. Water level loggers in monitoring wells provided low-cost monitoring of effectiveness over time and differences between trench designs. In addition, infiltration experiments were conducted to deliver a controlled volume of water to each trench. The center gravel trench with leaf filter drained more slowly during experiments. The monitoring showed that the gravel trench tended to have the highest peaks and responded to more storms. These differences were related to uneven water delivery, based on field observations during storms, controlled experiments, and similarity in response for the other two trenches. The water level recession rate did not decrease over time, indicating that clogging was not a significant factor. Maintenance that consisted of removing fines captured on the top of the sand trench did not significantly change infiltration in that trench. Monitoring with water level loggers was an effective method of determining that uneven delivery of water occurred among the three trenches, but there was no decrease in effectiveness of the trenches over the observation period, conclusions that could not be drawn by visual inspection alone.

Description: To determine the stability of rock slopes, discontinuity orientations must be measured accurately. Several methods exist for taking field measurements of discontinuity orientations. The objective of this study was to compare the traditional method of hand measuring discontinuity orientations using a Brunton compass to the more modern methods of measuring discontinuities using smartphone applications and ground-based light detection and ranging (LiDAR) laser scanning. The field site is a rock outcrop along Stroubles Road on Price Mountain, in Montgomery County, VA. The Price Mountain structure is a doubly plunging anticline exposed in a window in the Pulaski Thrust Sheet. The rock outcrop consists of a Mississippian sandstone mapped as the Upper Price Formation. The site features a set of bedding planes that dip steeply into the cut slope face, yielding toppling failures. In addition, two distinct sets of joints exist, creating both planar and wedge failures in the cut slope. Using window mapping, discontinuity orientations were measured along 200 ft (61 m) of outcrop using a Brunton compass, a smartphone application, and a laser scan. These measurements were compared using stereonet analyses to determine the relative accuracy of the different methods. The results show a strong agreement between measurements taken with the Brunton compass and the smartphone application. However, the laser scan shows that scanner data need calibration with field measurements and observations to yield equally good results. Remote-sensing methods using laser scanning, such as terrestrial photogrammetry, cannot be used completely independent of traditional field characterization and input from experienced professionals.

Description: In this study, we seek to improve our ability to predict the sustainability of a levee by analyzing the character of the surrounding environment. Utilizing geographic information systems (GIS), approximately 140 mi (225 km) of levees within the Lower Mississippi River Valley were divided into small segments and assigned a series of environmental factors, including the configuration of Quaternary geology with respect to the levee alignment, the hydrogeological characteristics of the alluvial uifer beneath the levee, and soil physical properties. Next, a binary logistic regression was applied to evaluate the correlation between environmental factors and development of levee distress features (seepage lines and sand boils) to generate a predictive model. Results of the logistic regression were then fed into a multiple criteria decision making (MCDM) system to categorize environments into levee sustainability groups. Logistic regression results indicated significant correlation between levee distress features and four environmental characteristics: paleo-channel orientation, soil classification, normalized difference vegetation index (NDVI), and saturated hydraulic conductivity. The predictive model correctly predicted the status of distress feature development with up to 62 percent accuracy. The MCDM system identified forests of sweetgum, Nuttall oak, and willow oak as areas of elevated levee sustainability. Plots of sycamore, pecan, and American elm trees and water bodies were rated as decreasing levee lifetime. With additional development, future models may serve as tools to improve our ability to assess, maintain, and design levee systems in better coherence with their natural surroundings.