Measured river leakages using conventional streamflow techniques: the case of Souhegan River, New Hampshire, USA

Multiple streamflow measurements were made at coupled discharge measurement stations to quantify rates of aquifer recharge and discharge on two reaches of the Souhegan River, New Hampshire, USA, flowing within a glacial-drift river-valley aquifer. The reaches included a predominantly losing (aquifer recharge) reach and a variable (aquifer recharge and discharge) reach located downstream of the former reach. River leakage, the differential between coupled upstream and downstream streamflow measurements along a reach, varied by almost 30 cubic feet per second (ft³/s) (0.85 m³/s) along the two reaches. The upper reach averaged 3.94 ft³/s (0.11 m³/s) loss whereas the lower reach averaged 4.85 ft³/s (0.14 m³/s) gain. At the upper reach, 13 losses were measured out of 19 coupled measurements. At the lower reach, ten out of 13 coupled measurements indicated gains in flow and suggest that this reach is primarily a gaining river reach. An important factor in river leakage appears to be antecedent trends in river stage. At the upper reach, gains were measured only during periods of declining river stage. Conversely, at the lower reach, streamflow loss was measured primarily during periods of rising river stage. Although some tendencies exist, several factors complicate the analysis of river leakage, most notably the inaccuracies in computed stream discharge.     

‘I want to take risks,like my mother’: Memory,affect, and Vietnamese masculinities – the legacy of gendered variations in socio-economic mobility during Ðổi mới

Young Vietnamese men who witnessed their mother's changing economic and labour market situations through the early years of Ð?i m?i (the policy of economic liberalization in Vietnam after 1986) have developed conceptions of masculinity that are ambivalent to notions of male power and authority within what is often termed the ‘traditional’ neo-Confucian family. On the basis of the life narratives of a small group of men in their early twenties, the author suggests that the value young men place on their mother's work and familial influence during Ð?i m?i contrasts with the findings of much gender scholarship on women's social and economic (im) mobility in the 1990s in Vietnam and on young men's own masculinist narratives. Most gender-sensitive research in this area has suggested that Vietnamese women remained curtailed in the early 1990s by a resurgence of male-oriented kinship systems and patriarchal structures at household level. However, the author discusses the young men as being equivocal. While invoking broad Confucian tropes, these men remember their mothers as economically dynamic relative to their fathers. This led to the informants citing their mother's histories of economic risk-taking as exemplifying free-market capability. Further, the finding suggests that Vietnamese women's social and economic mobility in the 1990s strongly affected young men's contemporary ideas and practices related to masculinity.     

Hydraulically Controlled Discrete Sampling from Open Boreholes

Groundwater sampling from open boreholes in fractured‐rock aquifers is particularly challenging because of mixing and dilution of fluid within the borehole from multiple fractures. This note presents an alternative to traditional sampling in open boreholes with packer assemblies. The alternative system called ZONFLO (zonal flow) is based on hydraulic control of borehole flow conditions. Fluid from discrete fractures zones are hydraulically isolated allowing for the collection of representative samples. In rough‐faced open boreholes and formations with less competent rock, hydraulic containment may offer an attractive alternative to physical containment with packers. Preliminary test results indicate a discrete zone can be effectively hydraulically isolated from other zones within a borehole for the purpose of groundwater sampling using this new method.     

A Stream‐Based Methane Monitoring Approach for Evaluating Groundwater Impacts Associated with Unconventional Gas Development

Gaining streams can provide an integrated signal of relatively large groundwater capture areas. In contrast to the point‐specific nature of monitoring wells, gaining streams coalesce multiple flow paths. Impacts on groundwater quality from unconventional gas development may be evaluated at the watershed scale by the sampling of dissolved methane (CH₄) along such streams. This paper describes a method for using stream CH₄ concentrations, along with measurements of groundwater inflow and gas transfer velocity interpreted by 1‐D stream transport modeling, to determine groundwater methane fluxes. While dissolved ionic tracers remain in the stream for long distances, the persistence of methane is not well documented. To test this method and evaluate CH₄ persistence in a stream, a combined bromide (Br) and CH₄ tracer injection was conducted on Nine‐Mile Creek, a gaining stream in a gas development area in central Utah. A 35% gain in streamflow was determined from dilution of the Br tracer. The injected CH₄ resulted in a fivefold increase in stream CH₄ immediately below the injection site. CH₄ and δ¹³C_CH4 sampling showed it was not immediately lost to the atmosphere, but remained in the stream for more than 2000 m. A 1‐D stream transport model simulating the decline in CH₄ yielded an apparent gas transfer velocity of 4.5 m/d, describing the rate of loss to the atmosphere (possibly including some microbial consumption). The transport model was then calibrated to background stream CH₄ in Nine‐Mile Creek (prior to CH₄ injection) in order to evaluate groundwater CH₄ contributions. The total estimated CH₄ load discharging to the stream along the study reach was 190 g/d, although using geochemical fingerprinting to determine its source was beyond the scope of the current study. This demonstrates the utility of stream‐gas sampling as a reconnaissance tool for evaluating both natural and anthropogenic CH₄ leakage from gas reservoirs into groundwater and surface water.     

A note on a paper by derome and dolph

Abstract

Some symmetries of the stability characteristies of a baroclinic zonal current are found, the basic state being that of the non-geostrophic Eady problem. In particular, they lead to a principle of exchange of stabilities.     

AN ASSESSMENT OF THE ADEQUACY OF THE SOLAR RADIATION DATA NETWORK FOR THE CONTIGUOUS UNITED STATES

Relationships between the coefficient of variability and the logarithm of extrapolation distance are established by an assessment of the spatial coherence of solar radiation. Equations for different confidence levels and daily and monthly time intervals are presented. These relationships are utilized in an assessment of the adequacy of the solar radiation data network in the contiguous United States. Results indicate that the present network maintained by the federal government provides adequate coverage on a monthly basis for all but 5% of the area for an error tolerance of ±10% at a 90% confidence level. However, on a daily basis, very inadequate spatial coverage is provided.     

Tropical cyclone contribution to extreme rainfall over southwest Pacific Island nations

Southwest Pacific nations are among some of the worst impacted and most vulnerable globally in terms of tropical cyclone (TC)-induced flooding and accompanying risks. This study objectively quantifies the fractional contribution of TCs to extreme rainfall (hereafter, TC contributions) in the context of climate variability and change. We show that TC contributions to extreme rainfall are substantially enhanced during active phases of the Madden–Julian Oscillation and by El Niño conditions (particularly over the eastern southwest Pacific region); this enhancement is primarily attributed to increased TC activity during these event periods. There are also indications of increasing intensities of TC-induced extreme rainfall events over the past few decades. A key part of this work involves development of sophisticated Bayesian regression models for individual island nations in order to better understand the synergistic relationships between TC-induced extreme rainfall and combinations of various climatic drivers that modulate the relationship. Such models are found to be very useful for not only assessing probabilities of TC- and non-TC induced extreme rainfall events but also evaluating probabilities of extreme rainfall for cases with different underlying climatic conditions. For example, TC-induced extreme rainfall probability over Samoa can vary from ~ 95 to ~ 75% during a La Niña period, if it coincides with an active or inactive phase of the MJO, and can be reduced to ~ 30% during a combination of El Niño period and inactive phase of the MJO. Several other such cases have been assessed for different island nations, providing information that have potentially important implications for planning and preparing for TC risks in vulnerable Pacific Island nations.

     

Glossary of Analytical and Metrological Terms from the International Vocabulary of Metrology (2008)

The Joint Committee for Guides in Metrology (JCGM) has introduced a revised third edition of the International Vocabulary of Metrology – basic and general concepts and associated terms ( VIM: 2008 ) that replaces the second edition which was published in 1993. This article includes a table containing the terms and definitions that are most relevant to geoanalysis, designed to extend awareness and to promote best practice in the use of this terminology. Comparison is made, where appropriate, with definitions from the earlier 1993 definitions, to demonstrate the way in which thinking in metrological concepts has evolved over this time period.     

Polycyclic aromatic hydrocarbons in commercial fish and lobsters from the coastal waters of Madagascar following an oil spill in August 2009

Concentrations of polycyclic aromatic hydrocarbons were determined in species of commercial fish and lobsters following an oil-spill just off the protected Madagascan coastline. Samples were collected along the coastline within and outside the affected area. Summed PAH concentrations ranged from 1.9 μg kg⁻¹ to 63 μg kg⁻¹ wet weight, but with no higher molecular weight PAHs (>202 Da) being detected. All concentrations of benzo[a]pyrene, benz[a]anthracene and dibenz[a,h]anthracene were <0.1 μg kg⁻¹ wet weight, well within the EU and UK set limits for the protection of human health. Additionally, samples were calculated as the benzo[a]pyrene toxic equivalency quotient (TEQ) and found to be well below the level of concern in relation to health of human consumers. Evaluation of the biota PAH data indicated the origin of PAH was predominantly petrogenic with >80% arising from oil sources. Profile studies indicate a low-level multisource petrogenic contamination probably representing a pre-spill background for the area.     

Application of a New Vertical Profiling Tool (ESASS) for Sampling Groundwater Quality During Hollow‐Stem Auger Drilling

A new tool called ESASS (Enhanced Screen Auger Sampling System) was developed by the U.S. Geological Survey. The use of ESASS, because of its unique U.S. patent design (U.S. patent no. 7,631,705 B1), allows for the collection of representative, depth‐specific groundwater samples (vertical profiling) in a quick and efficient manner using a 0.305‐m long screen auger during hollow‐stem auger drilling. With ESASS, the water column in the flights above the screen auger is separated from the water in the screen auger by a specially designed removable plug and collar. The tool fits inside an auger of standard inner diameter (82.55 mm). The novel design of the system constituted by the plug, collar, and A‐rod allows the plug to be retrieved using conventional drilling A‐rods. After retrieval, standard‐diameter (50.8 mm) observation wells can be installed within the hollow‐stem augers. Testing of ESASS was conducted at one waste‐disposal site with tetrachloroethylene (PCE) contamination and at two reference sites with no known waste‐disposal history. All three sites have similar geology and are underlain by glacial, stratified‐drift deposits. For the applications tested, ESASS proved to be a useful tool in vertical profiling of groundwater quality. At the waste site, PCE concentrations measured with ESASS profiling at several depths were comparable (relative percent difference <25%) to PCE concentrations sampled from wells. Vertical profiling with ESASS at the reference sites illustrated the vertical resolution achievable in the profile system; shallow groundwater quality varied by a factor of five in concentration of some constituents (nitrate and nitrite) over short (0.61 m) distances.