This article describes how urban development impacts on the processes that control river geomorphology and influence ecology. At the catchment scale, urban development transforms the hydrological ...system through construction of impervious surfaces and stormwater drainage systems. River water and sediment quality also are affected by stormwater and waste water drainage and by point and diffuse inputs of pollutants. Within the river channel network, widespread river engineering improves floodwater conveyance but imposes major changes in river network and channel characteristics. The results of an analysis of Urban River Survey data from 143 channel reaches in three European rivers (the River Tame, UK; the River Emscher, Germany; and the River Botic, Czech Republic) are presented to demonstrate the strong influence of river channel engineering on channel structure, physical habitat features and vegetation patterns. This analysis also shows the surprisingly varied character of urban rivers and thus their differential potential to respond to rehabilitation efforts. Because the success of river rehabilitation efforts depend not only on a scientific understanding of form and process within urban river systems but also on the acceptance and support of urban communities and integration within urban design and planning, the article briefly explores the coupling of natural and social science approaches to drive a more sustainable future for rivers in cities.
Tessier-type (1979) sequential extractions for heavy metals (Cd, Cr, Cu, Fe, Mn, Pb, and Zn) were conducted on sediments from two wetland sites, one inundated and the other drained, within the ...Indiana Dunes National Lakeshore (IDNL), NW Indiana, with the objective of (i) evaluating extraction techniques on organic-rich sediments, (ii) determining the geochemistry and mobility of potentially biotoxic trace metals in a contaminated environment, and (iii) considering the implications of different restoration strategies on the potential for heavy metal remobilization. Long and repeated extractions were needed to effectively degrade the organic-rich sediments (up to 75% of the sediment by mass). Analysis of sulfur fractionation revealed that it was predominantly sequestered along with the organically bound fraction (renamed oxidizable). Metal recovery was good with the sum of the extractant steps typically within 20% of the total metal concentration determined after total microwave digestion. Results showed metal fractionation to be both metal- and site-specific, The oxidizable fraction is dominant for Cu, Cr, and Fe (>65% of the nonresidual fraction for almost all samples) and overall is most important also for Cd and Pb. The iron/manganese oxide fraction is important for Pb, Mn, and Zn, particularly at the drained site. The carbonate bound fraction is relatively insignificant at both sites, except for Cd and Mn, although it is more important at the drained site. The exchangeable fraction is significant in the uppermost sediments at the drained site, particularly for Cd (3-24%), Pb (3-14%), and Zn (36-45%); whereas, for the inundated site, it ranged only from 0 to 1% Zn, with no detectable Cd or Pb. Chromium, Cu, and Fe exist in forms not likely to be remobilized, whereas Cd, Mn, Pb, and Zn are potentially mobile if drained wetland sites are reflooded (and pH and redox potential altered). Simple mass balance calculations illustrate the potential for the removal of approximately 84,375 kg of exchangeable Zn if currently drained sites across the IDNL are reflooded, with concentrations in water draining into Lake Michigan as high as 5 ppm.
This commentary is a response to the Area commentary by Mark Griffiths and Kate Baker, which draws focus on the problematic prominence of colonial material histories at the Royal Geographical Society ...(with IBG)'s Lowther Lodge site. We outline an undergraduate field trip – run collaboratively by University College London (UCL) and the RGS‐IBG since 2018 – for first‐year UCL geography students that aims to make them both aware of geography's problematic colonial histories, and party to the ways the discipline is changing and critically engaging with its past. Positioned at the intersections of teaching and research, we highlight this field trip because we believe it stands as an example of precisely the kind of decolonial engagement with the RGS‐IBG for which Griffiths and Baker call.
This commentary describes a decolonial field trip run jointly by UCL and the RGS‐IBG for UCL's first year undergraduate geography students.
Applied climatology: urban climate Souch, Catherine; Grimmond, Sue
Progress in physical geography,
04/2006, Letnik:
30, Številka:
2
Journal Article
Recenzirano
Given the large and ever-increasing number of urban inhabitants globally, and the profound effects of cities and their inhabitants on the atmosphere, both within and beyond urban limits, ...ever-increasing attention is being directed to the study of urban climates. The underlying rationale for these urban climate studies varies: ranging from the need to know more about the fundamental physics, biology or chemistry of urban atmospheres, and to integrate such understanding in operational weather forecasting and air quality models; interest in environmental sustain-ability and the desire to plan settlements and build houses that are more energy and water efficient; concerns about environmental health, whether related to air quality, heat stress; or 'homeland security' and the dispersion of toxic substances in cities.
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