Evaluating a process‐based model for use in streambank stabilization: insights on the Bank Stability and Toe Erosion Model (BSTEM)

Streambank retreat is a complex cyclical process involving subaerial processes, fluvial erosion, seepage erosion, and geotechnical failures and is driven by several soil properties that themselves are temporally and spatially variable. Therefore, it can be extremely challenging to predict and model the erosion and consequent retreat of streambanks. However, modeling streambank retreat has many important applications, including the design and assessment of mitigation strategies for stream revitalization and stabilization. In order to highlight the current complexities of modeling streambank retreat and to suggest future research areas, this paper reviewed one of the most comprehensive streambank retreat models available, the Bank Stability and Toe Erosion Model (BSTEM), which has recently been integrated with several popular hydrodynamic and sediment transport models including the Hydrologic Engineering Center's River Analysis System (HEC‐RAS). The objectives of this paper were to: (i) comprehensively review studies that have utilized BSTEM and report their findings, (ii) address the limitations of the model so that it can be applied appropriately in its current form, and (iii) suggest directions of research that will help make the model a more useful tool in future applications. The paper includes an extensive overview of peer reviewed studies to guide future users of BSTEM. The review demonstrated that the model needs further testing and evaluation outside of the central United States. Also, further development is needed in terms of accounting for spatial and temporal variability in geotechnical and fluvial erodibility parameters, incorporating subaerial processes, and accounting for the influence of riparian vegetation on streambank pore‐water pressure dynamics, applied shear stress, and erodibility parameters. Copyright © 2016 John Wiley & Sons, Ltd.     

Community preparedness for lava flows from Mauna Loa and Hualālai volcanoes,Kona, Hawai‘i

Lava flows from Mauna Loa and Huallai volcanoes are a major volcanic hazard that could impact the western portion of the island of Hawaii (e.g., Kona). The most recent eruptions of these two volcanoes to affect Kona occurred in a.d. 1950 and ca. 1800, respectively. In contrast, in eastern Hawaii, eruptions of neighboring Klauea volcano have occurred frequently since 1955, and therefore have been the focus for hazard mitigation. Official preparedness and response measures are therefore modeled on typical eruptions of Klauea.The combinations of short-lived precursory activity (e.g., volcanic tremor) at Mauna Loa, the potential for fast-moving lava flows, and the proximity of Kona communities to potential vents represent significant emergency management concerns in Kona. Less is known about past eruptions of Huallai, but similar concerns exist. Future lava flows present an increased threat to personal safety because of the short times that may be available for responding.Mitigation must address not only the specific characteristics of volcanic hazards in Kona, but also the manner in which the hazards relate to the communities likely to be affected. This paper describes the first steps in developing effective mitigation plans: measuring the current state of peoples knowledge of eruption parameters and the implications for their safety. We present results of a questionnaire survey administered to 462 high school students and adults in Kona. The rationale for this study was the long lapsed time since the last Kona eruption, and the high population growth and expansion of infrastructure over this time interval. Anticipated future growth in social and economic infrastructure in this area provides additional justification for this work.The residents of Kona have received little or no specific information about how to react to future volcanic eruptions or warnings, and short-term preparedness levels are low. Respondents appear uncertain about how to respond to threatening lava flows and overestimate the minimum time available to react, suggesting that personal risk levels are unnecessarily high. A successful volcanic warning plan in Kona must be tailored to meet the unique situation there.     

A method for uncertainty constraint of catchment discharge and phosphorus load estimates

River discharge and nutrient measurements are subject to aleatory and epistemic uncertainties. In this study, we present a novel method for estimating these uncertainties in colocated discharge and phosphorus (P) measurements. The “voting point”‐based method constrains the derived stage‐discharge rating curve both on the fit to available gaugings and to the catchment water balance. This helps reduce the uncertainty beyond the range of available gaugings and during out of bank situations. In the example presented here, for the top 5% of flows, uncertainties are shown to be 139% using a traditional power law fit, compared with 40% when using our updated “voting point” method. Furthermore, the method is extended to in situ and lab analysed nutrient concentration data pairings, with lower uncertainties (81%) shown for high concentrations (top 5%) than when a traditional regression is applied (102%). Overall, for both discharge and nutrient data, the method presented goes some way to accounting for epistemic uncertainties associated with nonstationary physical characteristics of the monitoring site.     

Treatment of Malting Wastewater in a Granular Sludge Sequencing Batch Reactor (SBR)

Aerobic granular sludge was successfully cultivated in a sequencing batch reactor (SBR) treating wastewater from the malting process with a high content of particulate organic matter. At an organic loading rate of 3.2 kg/(m³ d) COD_total and an influent particle concentration of 0.95 g/L MLSS an average removal of 50% in COD_total and 80% in COD_dissolved could be achieved. A comparison of granular and flocculent sludge grown under the same operating conditions showed no significant difference in removal efficiency although granules exhibited a higher metabolic activity in terms of specific oxygen uptake rate (r_{O2, X}). Two distinct mechanisms of particle removal were observed for granular sludge: during initial granule formation, particles were incorporated into the biofilm matrix. For mature granules, a high level of protozoa growth on the granule surface accounted for the ability to remove particulate COD. Combined evaluation of the development in MLSS content and sludge bed settling rate (i.e., mean derivative of the normalized sludge volume) was found to be an adequate method for monitoring the characteristic settling properties of a granulizing sludge bed. By means of this method, a distinct substrate gradient out of several operating conditions was concluded to have the biggest impact on the formation of aerobic granular sludge.     

Bacterial communities are sensitive indicators of contaminant stress

With many environments worldwide experiencing at least some degree of anthropogenic modification, there is great urgency to identify sensitive indicators of ecosystem stress. Estuarine organisms are particularly vulnerable to anthropogenic contaminants. This study presents bacterial communities as sensitive indicators of contaminant stress. Sediments were collected from multiple sites within inner and outer zones of three heavily modified and three relatively unmodified estuaries. Bacterial communities were censused using Automated Ribosomal Intergenic Spacer Analysis and analysed for a suite of metal and PAH contaminants. Shifts in both bacterial community composition and diversity showed strong associations with sediment contaminant concentrations, particularly with metals. Importantly, these changes are discernable from environmental variation inherent to highly complex estuarine environments. Moreover, variation in bacterial communities within sites was limited. This allowed for differences between sites, zones and estuaries to be explained by variables of interest such as contaminants that vary between, but not within individual sites.     

Bioremediation perspective of historically contaminated sediment with polycyclic aromatic hydrocarbons

The purpose of the current study is to compare the influence of different aerobic conditions(biostimulation(BS),bioaugmentation(BA),and a combination of biostimulation and bioaugmentation(BB))on polycyclic aromatic hydrocarbons(PAH)degradation and compare the degraded amount with single step XAD-4 extraction as a new tool for bioavailability assessment for chronically contaminated sediment samples obtained from territory of Autonomous Province Vojvodina of Serbia(S1,S2,and S3).A great number of papers dealing with biodegradation of PAHs in spiked sediment or soil have been published,but to the authors’knowledge,a limited number of papers studied aged,historically polluted sediment and a sum of chosen U.S.Environmental Protection Agency(USEPA)PAHs.A significant reduction(up to67%)in PAH concentration was observed,while the percentage of reduction varied depending on the sediment sample and treatment used.BS treatment successfully stimulated growth of indigenous bacteria.Further,PAH-degrading strain Sphingomonas paucimobilis F8 inoculated in BA and BB treatment survived for up to 7 weeks after it was suppressed by unfavorable conditions or native microbes.Degraded amounts generally showed good correlation with results obtained from XAD-4 extraction.Results obtained in the current study represent a good start for standardizing a XAD-4 extraction technique as a simplified,easier,and lower cost method for bioavailability assessment.     

Closed Circuit Television (CCTV) Earthquake Behaviour Coding Methodology: analysis of Christchurch Public Hospital video data from the 22 February Christchurch earthquake event

Earthquake epidemiological research indicates that the behavioural response influences the nature and severity of injuries sustained. However, there is no observational evidence of the actions individuals engage in during and immediately following earthquake shaking, and the context in which earthquake injuries and deaths are caused. Closed Circuit Television Earthquake Behaviour Coding Methodology has been developed as a tool to classify human behaviour during and immediately following earthquake shaking using real event video data. The coding methodology was applied to security video data captured during the 22 February 2011 M_w6.3 ‘Christchurch’ earthquake event from the Christchurch Public Hospital which experienced shaking intensity of MM9 lasting approximately 12–15 s. We applied this coding methodology to determine: demography, trans-event behavioural responses, post-event behavioural responses, influence of social context on behaviour, and influence of behaviour on injuries. A total of 213 individuals from 31 different camera views were analysed. Sixty-six per cent of the individuals were adult-aged females. The primary trans-event responses were to hold (26%) onto furniture, walls, and/or other people close to them and to look around (30%). No individuals were observed to perform all ‘Drop, Cover, Hold’ actions, the recommended action during strong earthquake shaking in New Zealand. Post-event behaviour included: running, walking, providing assistance, moving towards others, visual communication, and some individuals gave instructions. Social contextual behaviour varied depending on the role of the adult. There were no serious injuries linked to behaviour. The results of this initial study indicate the coding methodology can record the distribution of and variation in human behaviours. Therefore, objective observation of earthquake video data can provide a useful quantitative measure of human behaviour. Significantly, the process will enable researchers to look more closely at behaviours, as well as the social and physical contexts associated with injury risk during and immediately following earthquake shaking.     

Upright crinoids of the Thornton Reef,Wenlock (Silurian) of Illinois,USA

The rare preservation of columns perpendicular to bedding may provide convincing evidence that ancient crinoids adopted an upright attitude during life. However, taphonomic and sedimentological analyses are important in determining whether such occurrences are truly in situ or represent unusual allochthonous accumulations. The Crinoid Biosome of the Thornton Reef Complex, Silurian of Illinois, USA, includes pluricolumnals preserved perpendicular to bedding, in association with more common specimens parallel or angled to bedding. Upright pluricolumnals are relatively shorter (<150 mm) than the longest non-upright specimens; they sometimes occur as imbricate accumulations and lack attachment structures (although these are preserved separately). Brachiopod valves and colonial corals may also be preserved perpendicular to bedding. These features suggest that the Thornton beds were formed as viscous mass flow deposits and that the upright crinoid columns are allochthonous or, at best, parautochthonous. © 1996 John Wiley & Sons, Ltd.     

Regional fluid flow and the genesis of Irish Carboniferous base metal deposits

The Irish carbonate-hosted base metal deposits have long been an enigmatic subclass of deposit. Some of the Irish deposits (Harberton Bridge, Allenwood) are clearly epigenetic, hosted in breccia pipes and have close affinities to Mississippi Valley-type deposits. Others, are characterised by stratabound and sometimes stratiform mineralisation (Abbeytown, Navan), while a third group is associated closely with concordant dolomitic breccias and cavity fill mineralisation at the base of carbonate mud mounds (Lisheen, Ballinalack). When the stratigraphic and textural evidence is reviewed, it is apparent that all of the base metal mineralisation occurred in already compacted sediments. Hence, mineralisation probably occurred at depths of at least several 100 m depth below the sea bed. The mineralisation occurred either during transtensional Lower Carboniferous basin development, or subsequently, during the onset of Variscan shortening. Fluids may have been derived from dewatering of Variscan-driven deformation to the south of the carbonate platform, with fluid flow through major fracture zones and basal clastic aquifers. Alternatively, high heat flow produced by Lower Carboniferous extension may have driven the mineralising system. Syn-genetic models are extremely difficult to sustain.     

Dissolved oxygen as an indicator of bioavailable dissolved organic carbon in groundwater

Concentrations of dissolved oxygen (DO) plotted vs. dissolved organic carbon (DOC) in groundwater samples taken from a coastal plain aquifer of South Carolina (SC) showed a statistically significant hyperbolic relationship. In contrast, DO-DOC plots of groundwater samples taken from the eastern San Joaquin Valley of California (CA) showed a random scatter. It was hypothesized that differences in the bioavailability of naturally occurring DOC might contribute to these observations. This hypothesis was examined by comparing nine different biochemical indicators of DOC bioavailability in groundwater sampled from these two systems. Concentrations of DOC, total hydrolysable neutral sugars (THNS), total hydrolysable amino acids (THAA), mole% glycine of THAA, initial bacterial cell counts, bacterial growth rates, and carbon dioxide production/consumption were greater in SC samples relative to CA samples. In contrast, the mole% glucose of THNS and the aromaticity (SUVA(254)) of DOC was greater in CA samples. Each of these indicator parameters were observed to change with depth in the SC system in a manner consistent with active biodegradation. These results are uniformly consistent with the hypothesis that the bioavailability of DOC is greater in SC relative to CA groundwater samples. This, in turn, suggests that the presence/absence of a hyperbolic DO-DOC relationship may be a qualitative indicator of relative DOC bioavailability in groundwater systems.