The Role of Overwash in the Evolution of Mixing Zone Morphology Within Barrier Islands

Overwash is a major controlling factor in the morphology of the mixing zone of coastal aquifers. Conceptual models of the mixing zone describe an interface controlled by tidal oscillations, wave run-up, and other factors; however, few describe the influence of large storm events. In August 1993, Hatteras Island, North Carolina, USA, experienced a 3-m storm surge due to Hurricane Emily. Sound-side flooding infiltrated a wellfield, causing a dramatic increase in TDS levels that persisted for more than 3 years. Two-dimensional simulations with SUTRA, the USGS finite-element model, are calibrated to the TDS breakthrough data of this storm to infer model dispersivity values. Simulations using the calibrated dispersivity values, predicted flooding levels, and 54 years of hurricane records to determine the influence of the overwash events suggest that it is rare for the mixing zone to approximate the conceptual morphology. Even during quiescent periods such as between 1965 and 1975, TDS levels do not return to theoretical levels before being elevated by a subsequent storm event. Thus, while tidal oscillations and other factors are important to mixing zone development, basic wind events and more severe storm events may have more influence and lasting effect on the morphology of the mixing zone

Changes In Stream Temperatures In Response To Restoration Of Groundwater Discharge And Solar Heating In A Culverted, Urban Stream

Boone Creek is a mountainous headwater stream that lies within an urbanized environment in northwestern North Carolina. The primary source of thermal pollution in Boone Creek is the urban infrastructure, which affects stream temperatures through (1) heated runoff, which creates temperature surges and (2) the elimination of groundwater–surface water interactions. In this study, we use a Monte Carlo thermal mixing model to predict the thermal impact of removing a 700-m-long culvert. Our thermal mixing model balances stream discharge and temperatures with surface-heat exchange parameters and restored base?ow. We calculate the daily-average groundwater discharge velocity at 15 locations in the stream using signal decay in streambed temperatures, and utilize a Monte Carlo implementation of the heterogeneous base?ow ?eld in the thermal mixing model. We also calculate surface-heat exchange per unit area for conditions upstream and downstream of the existing culvert and utilize those values in the thermal mixing model. Our modeled temperatures suggest a decrease in summer stream temperatures downstream of the culvert that average 1.35 °C and 1.17 °C for upstream and downstream surface-heat exchange conditions, respectively. The results of our study have implications for the balance between base?ow and the urban infrastructure in any high-gradient urban stream that experiences similar thermal effects

Riparian Biogeochemical Hot Moments Induced By Stream Fluctuations

Hyporheic exchanges in riparian zones induced by stream stage fluctuations, referred to as bank storage, can influence contaminant transport and transformation when mixing of groundwater and surface waters with distinct chemical signatures occur, which might lead to a high biochemical activity. The effect of bank storage on nutrient transport was analyzed here using a two-dimensional, variably saturated and multi-species reactive transport model, which accounted for the water flow and solute transport and reactions within riparian zones. After verification with field observations, our model demonstrated that high biogeochemical activities occurred at the near-stream riparian zone during stage fluctuation, a process referred to as bank storage hot moment (BSHM). We used Monte Carlo simulations to study the uncertainty of BSHM and related nutrient dynamics to biogeochemical and hydrological factors. The results indicated that stream fluctuations can lead to maximum bank storage volume ranging from 0 to 259 m3 m1 of stream linear length (median ¼ 9.7 m3 and SD ¼ 53.2 m3). Taking denitrification as an example, BSHM can lead to considerable NO3 removal with a median removal rate of 2.1 g d1 and SD of 17.2 g d1 per meter of stream linear length. The NO3 uptake velocity (median ¼ 2.7 105 and SD ¼ 2.4 104 mmin1) was comparable to that of in-stream transient storage from the literature. This result suggests that BSHM may be a significant process contributing to the nutrient budget at the ecosystem level. Finally, a theoretical framework representing the coupled hydrobiogeochemical controls on riparian hot spots was developed to help predicting when BSHM can become important in a particular stream

Air-Stream Temperature Correlation In Forested And Urban Headwater Streams In The Southern Appalachians

Air temperature can be an effective predictor of stream temperature. However, little work has been done in studying urban impacts on air-stream relationships in groundwater-fed headwater streams in mountainous watersheds. We applied wavelet coherence analysis to two 13-month continuous (1 hr interval) stream and air temperature datasets collected at Boone Creek, an urban stream, and Winkler Creek, a forest stream, in northwestern North Carolina. The main advantage of a wavelet coherence analysis approach is the ability to analyse non-stationary dynamics for the temporal covariance between air and stream temperature over time and at multiple temporal scales (e.g. hours, days, weeks and months). The coherence is both time and scale-dependent. Our research indicated that air temperature generally co-varied with stream temperature at time scales greater than 0.5 day. The correlation was poor during the winter at the scales of 1 to 64 days and summer at the scales of 1.5 to 4 days, respectively. The empirical models that relate air temperature to stream temperature failed at these scales and during these periods. Finally, urbanization altered the air-stream temperature correlation at intermediate time scales ranging from 2 to 12 days. The correlation at the urban creek increased at the 12-day scale, whereas it decreased at scales of 2 to 7 days as compared with the forested stream, which is probably due to heated surface runoff during summer thunderstorms or leaking stormwater or wastewater collection systems. Our results provide insights into air-stream temperature relationships over both time and scale domains. Identifying controls over time and scales are needed to predict water temperature to understand the future impacts that interacting climate and land use changes will have on aquatic ecosystem in river networks. Copyright © 2014 John Wiley & Sons, Ltd

Effect Of Interannual Climate Oscillations On Rates Of Submarine Groundwater Discharge (Article #2)

Submarine groundwater discharge (SGD) is an important component of the coastal hydrologic cycle, affecting mixing and bio-geochemistry in the nearshore environment. El Niño–Southern Oscillation (ENSO) influences rates of precipitation and groundwater recharge in many regions, including barrier islands of the southeastern U.S. coast; however, the influence of ENSO on SGD is poorly understood for this region. Here we investigate the role of ENSO in controlling recharge and SGD at inter-annual time scales, using modeling results for both real and generic barrier island environments. Results of our 57 year simulations show that the freshwater component of seasonally averaged SGD as well as groundwater discharge velocity, water table elevation, and submarine groundwater recharge are significantly correlated with ENSO for a real barrier island (Hatteras Island, North Carolina) and, under certain conditions, for generics. These correlations persist for lag times as great as 5 months during winter, creating anomalies of up to 35% between El Niño and La Niña conditions and suggesting that both hydrologic cycling and biogeochemical cycling in these systems are significantly influenced by ENSO

Effect Of Interannual And Interdecadal Climate Oscillations On Groundwater In North Carolina (Article #1)

Multi-year climate oscillations such as the El Nino–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) affect precipitation and stream discharge rates in the western hemisphere. While inferences may be drawn between these hydroclimatological relationships and groundwater conditions, few studies explicitly link groundwater conditions to these cycles. Here we investigate relationships between winter ENSO, PDO, and lagging baseflow rates in the southeastern United States. We find strong correlation between winter ENSO and lagged baseflow in coastal North Carolina which, coupled with anomalies in mean baseflow, decrease with distance inland from the coast. Our results demonstrate that interannual and interdecadal climate oscillations in the Pacific Ocean have a strong effect on hydrological processes in eastern North America despite filtering by the groundwater flow process. These results have implications for water resource availability in regions where water management is complicated by population growth and climatic uncertainty

A Brief Survey Of Manifolds And Vector Bundles

This is a survey of various key components and machinery used in modern differential geometry. We begin with an introduction to multilinear algebra up to basic notions of tensors and exterior algebras. A survey of basic topology and manifold theory is then presented. This includes a formulation of tangent spaces, vector bundles, and sections on a manifold. This paper then concludes with an introduction to semi-Riemannian geometry including an outline of metrics, connections, and covariant differentiation

Modeling The Effects Of Roadside And Meadow Foliage Management On The Dynamics Of Bombus Impatiens Populations

Populations of pollinators, including the common ground bumble bee Bombus impatiens, can suffer declines due to a lack of flower resources. Flower resources can be influenced by a variety of natural and anthropogenic factors. There is evidence that regimented foliage management significantly alters the availability of pollinator-relevant flowers. Here I report on field studies testing the effects of foliage management (mowing) on the abundance of five flowering plant species. I then outline a mathematical model based on B. impatiens life history to predict the impacts of mowing regimes on the bees’ population dynamics. I used flower phenology surveys to determine the inflorescence density of my five target flower species within two habitats under different foliage management regimes. Surveys indicated that cutting back foliage significantly reduced the number of inflorescences when species were pooled. When considered individually, only Solidago rugosa showed reduction due to mowing. I then incorporated inflorescence density data into mathematical projections of the total nectar produced within an explicit landscape under different hypothetical foliage management regimes. The outcomes of this model suggest that implementing mowing practices influence the ability of Bombus impatiens to produce new queens and thus to their ability to persist in relatively higher abundance

"The Weapons in Our Hands are Limitless": The Protocols of The Elders of Zion's Influence on Adolf Hitler and Nazi Germany

In the first years of the twentieth century, an anti-Semitic document appeared in Russia that profoundly shaped the course of the entire century. Despite being quickly discredited as a plagiarized forgery, The Protocols of the Elders of Zion spread across the world, being translated into dozens of languages and utilized as hateful rhetoric by leaders of many religions and nationalities. While the effects of the document were felt internationally, the Protocols also helped to reshape centuries old prejudices about Jews in a country still in its infancy, Germany. This “hoax of the twentieth century” helped to redefine age-old anti-Semitic values firmly ingrained within German society, and helped Adolf Hitler and his Nazi Party justify committing the landmark genocide of world history, the Holocaust. Utilizing a variety of sources, particularly the actual text of the Protocols and the writings of Adolf Hitler, this examination argues that Hitler and his cabinet became progressively more radicalized towards extermination of the Jews due to their belief in the Jewish world conspiracy outlined within the Protocols

Principal perceived preparedness to lead the implementation of the common core

The purpose of this study was to investigate the self-perceptions of North Carolina principals regarding their preparedness to lead the implementation of the Common Core Standards in their schools. Specifically, this study was designed to determine the following: (a) how do principals from across North Carolina perceive their efficacy for leading the implementation of the Common Core Standards? (b) what are the factors related to principal perceptions of self-efficacy for leading the implementation of the Common Core Standards? The design of this study followed closely the design of Keith (2008) when she conducted a similar survey of Virginia principals as to their desire for professional development in meeting the requirements of the No Child Left Behind Act. Each North Carolina principal was surveyed on a voluntary basis and all principals who responded were included in the study. The major finding of the study was that in the survey’s 26 efficacy statements significant relationships were found between demographic question 10: Number of hours of training in Common Core (Instruction, Pedagogy, Revised Blooms Taxonomy) and 23 of the efficacy statements (See Appendix A). When statements of efficacy were ranked, principals said that efficacy statement 26, Satisfaction with Common Core training I have received from outside of my district, represented an area of least efficacy. Furthermore, support received from district office regarding financial support, professional development, response to concerns, Common Core training and communication were all areas that ranked low for principals with regard to support from their district offices