The role of long‐term human impact on avulsion and fan development

This study aims to understand (mainly qualitatively) the long‐term role of human impact on avulsion processes and the development of fluvial (mega‐) fans in semi‐arid environments. In this paper we refer to human impact as the direct influences of actions on the river's hydraulics (i.e. flow regulation, flow diversion and channel engineering). In five case‐studies drawn from the Khuzestan plains in southwest Iran we have analysed the setup and triggering conditions of specific avulsions that occurred in the past (timescale of millennia) and identified the role of human interference in their causation. Our analysis is based on the integration of historical, archaeological, geomorphological and geological data. Through this study we demonstrate that avulsions in the Khuzestan plains are the result of long‐term and complex interplay between multiple human‐induced and natural causes. In similar ways human‐induced actions may play important roles during different phases of avulsion development. The ‘success‘ of an avulsion in the post‐triggering phase may be defined by human‐induced setup causes as well as morphodynamic processes. We suggest that present‐day flood events may be partly inherited from long‐term human alterations of the natural processes. These finding could have implications for any fluvial system (e.g. distributive fluvial systems, deltas) where avulsion plays a major role in their development and research tends to emphasize on natural mechanisms. Copyright © 2016 John Wiley & Sons, Ltd.     

A Review of “Renewable Energy Project Development Under the Clean Development Mechanism: A Guide for Latin America”

Books reviewed in this article:

Kurt E. Engelmann and Vjeran Pavlakovic (eds.), Rural Development in Eurasia and the Middle East: Land Reform, Demographic Change, and Environmental Constraints

Gregory C. Randall, America's Original GI Town: Park Forest, Illinois

John B. Rehder, Delta Sugar: Louisiana's Vanishing Plantation Landscape

Cathy D. Knepper, Greenbelt, Maryland: A Living Legacy of the New Deal

Char Miller (ed.), Fluid Arguments: Five Centuries of Western Water Conflict

Edward F. Bergman, The Spiritual Traveler: New York City: The Guide to Sacred Spaces and Peaceful Places

Rachel Pain, Michael Barke, Duncan Fuller, Jamie Gough, Robert MacFarlane, and Graham Mowl, Introducing Social Geographies

Tor A. Benjaminsen, and Christian Lund, (eds.), Politics, Property, and Production in the West African Sahel: Understanding Natural Resources Management

Al Gedicks, Resource Rebels: Native Challenges to Mining and Oil Corporations

Maryann P. Feldman and Nadine Massard (eds.), Institutions and Systems in the Geography of Innovation

Richard Foglesong, Married to the Mouse: Walt Disney World and Orlando

Annick Germain, and Damaris Rose, Montréal: The Quest for a Metropolis

George F. Rengert, Mark T. Mattson, and Kristin D. Henderson, Campus Security: Situational Crime Prevention in High–Density Environments

Vaclav Smil, Feeding the World: A Challenge for the Twenty–First Century

Pu Miao (ed.), Public Places in Asia Pacific Cities: Current Issues and Strategies

Lisa M. Benton and John Rennie Short (eds.), Environmental Discourse and Practice: A Reader

Philip Scranton (ed.), The Second Wave: Southern Industrialization from the 1940s to the 1970s

Barry Dalal–Clayton and David Dent, Knowledge of the Land: Land Resources Information and Its Use in Rural Development     

Tectono‐sedimentary evolution of the western Corinth rift (Central Greece)

The Corinth rift (Greece) is one of the world's most active rifts. The early Plio‐Pleistocene rift is preserved in the northern Peloponnese peninsula, south of the active Corinth rift. Although chronostratigraphic resolution is limited, new structural, stratigraphic and sedimentological data for an area >400 km² record early rift evolution in three phases separated by distinct episodes of extension rate acceleration and northward fault migration associated with major erosion. Minimum total N–S extension is estimated at 6.4–7.7 km. The earliest asymmetrical, broad rift accommodated slow extension (0.6–1 mm a^?1) over >3 Myrs and closed to the west. North‐dipping faults with throws of 1000–2200 m defined narrow blocks (4–7 km) with little footwall relief. A N‐NE flowing antecedent river system infilled significant inherited relief (Lower group). In the earliest Pleistocene, significant fluvial incision coincided with a 15 km northward rift margin migration. Extension rates increased to 2–2.5 mm a^?1. The antecedent rivers then built giant Gilbert‐type fan deltas (Middle group) north into a deepening lacustrine/marine basin. N‐dipping, basin margin faults accommodated throws <1500 m. Delta architecture records initiation, growth and death of this fault system over ca. 800 ka. In the Middle Pleistocene, the rift margin again migrated 5 km north. Extension rate increased to 3.4–4.8 mm a^?1. This transition may correspond to an unconformity in offshore lithostratigraphy. Middle group deltas were uplifted and incised as new hangingwall deltas built into the Gulf (Upper group). A final increase to present‐day extension rates (11–16 mm a^?1) probably occurred in the Holocene. Fault and fault block dimensions did not change significantly with time suggesting control by crustal rheological layering. Extension rate acceleration may be due to strain softening or to regional tectonic factors.     

The Effects of Integrated Marsh Management (IMM) on Salt Marsh Vegetation,Nekton, and Birds

An integrated marsh management (IMM) project in an urbanized watershed on Long Island, New York, USA, aimed to mitigate salt marsh degradation and to reduce mosquito production by an innovative combination of restoration and open marsh water management methods. The grid ditch network at two treatment marshes was replaced with naturalized tidal channels and ponds. Effects of the hydrologic alterations were monitored utilizing a before–after–control–impact approach. The treatment marshes experienced a number of beneficial outcomes including a fourfold reduction in the invasive Phragmites australis and increased native vegetation cover in the most degraded portions of the marsh, increased abundance and diversity of marsh killifish and estuarine nekton species, higher shorebird and waterfowl densities, and increased avian species diversity. The successful implementation of IMM concept led to improved marsh health and diminished mosquito production. Therefore, this study may serve as a template for similar large-scale integrated salt marsh restoration projects.     

Market intermediaries and rural people in Bolivia's forest products sector: Are trusting partnerships possible?

Decentralization in access to and control of Bolivia's forest resources, coupled with a rising global demand for tropical hardwoods, raises important questions about whether increased trade and community forest management (CFM) initiatives can enable forms of market integration that have more favourable outcomes for rural communities. This paper assesses the prospects for such a transition through an examination of the relationships linking wood product market intermediaries (brokers and buyers) to rural suppliers and forest communities in Bolivia. The analysis centres on whether trust – conceptualized as a power‐laden sociospatial process driven by multiscalar factors – can evolve between buyers and suppliers such that more progressive (sustainable and mutually beneficial) partnerships devolop. Focusing on three types of buyer–supplier relationships in Bolivia – direct ties between wood brokers/buyers and suppliers, nongovernmental organization (NGO) mediated exchange relationships and Forest Stewardship Council (FSC) certification of suppliers – our findings show how trust building initiatives that focus on one scale may fail if factors at other scales create obstacles to collaboration, Given these relational constraints, CFM strategies in Bolivia currently face limitation on their viability as economic development strategies.     

FT-IR measurements of cold C3H8 cross sections at 7–15 μm for Titan atmosphere

We present absorption cross sections of propane (C₃H₈) at temperatures from 145 K to 297 K in the 690–1550 cm⁻¹ region. Pure and N₂-broadened spectra were measured at pressures from 3 Torr to 742 Torr using a Bruker IFS125 FT-IR spectrometer at JPL. The gas absorption cell, developed at Connecticut College, was cooled by a closed-cycle helium refrigerator. The cross sections were measured and compiled for individual spectra recorded at various experimental conditions covering the planetary atmosphere and Titan. In addition to the cross sections, a propane pseudoline list with a frequency grid of 0.005 cm⁻¹, was fitted to the 34 laboratory spectra. Line intensities and lower state energies were retrieved for each line, assuming a constant width. Validation tests showed that the pseudoline list reproduces discrete absorption features and continuum, the latter contributed by numerous weak and hot band features, in most of the observed spectra within 3%. Based on the pseudoline list, the total intensity in the 690–1550 cm⁻¹ region was determined to be 52.93 (±3%) × 10⁻¹⁹ cm⁻¹/(molecule cm⁻²) at 296 K; this value is within 3% of the average from four earlier studies. Finally, the merit of the pseudoline approach is addressed for heavy polyatomic molecules in support of spectroscopic observation of atmospheres of Titan and other planets. The cold cross sections will be submitted to the HITRAN database (hitran.harvard.edu), and the list of C₃H₈ pseudolines will be available from a MK-IV website of JPL (http://mark4sun.jpl.nasa.gov/data/spec/Pseudo).     

Bastnaesite from Kanigiri granite, Prakasam district, Andhra Pradesh

For the first time we report bastnaesite and hydroxyl bastnaesite (lanthanum cerium fluoro-carbonate) from the Kanigiri granite. The host granitoids are of A-type and vary in composition from quartz syenites to peralkaline granites. Rare metal and rare earth-bearing minerals identified by X-ray diffraction (XRD) studies in Kanigiri granite are bastnaesite and hydroxyl bastnaesite, besides columbite-tantalite, monazite, fergusonite, thorite and euxenite. Petromineralogical studies have also revealed the presence of bastnaesite. The presence of bastnaesite in Kanigiri granite suggests that the host felsic rocks may also form a potential source for light rare earth mineral, bastnaesite, apart from the already known rare-metal minerals.     

A discontinuous Galerkin method for two-phase flow in a porous medium enforcing H(div) velocityand continuous capillary pressure

We consider the slightly compressible two-phase flow problem in a porous medium with capillary pressure. The problem is solved using the implicit pressure, explicit saturation (IMPES) method, and the convergence is accelerated with iterative coupling of the equations. We use discontinuous Galerkin to discretize both the pressure and saturation equations. We apply two improvements, which are projecting the flux to the mass conservative H(div)-space and penalizing the jump in capillary pressure in the saturation equation. We also discuss the need and use of slope limiters and the choice of primary variables in discretization. The methods are verified with two- and three-dimensional numerical examples. The results show that the modifications stabilize the method and improve the solution.