Development of new dunes in the Dutch Delta: nature compensation and ‘building with nature’

A new dune area was constructed by beach and foreshore nourishments along the Delfland Coast in the southwestern Netherlands. The new area is intended to be a compensation for losses of existing high quality dunes in nearby areas, due to the use/construction of Maasvlakte 2, the new harbour extension of Rotterdam opening in 2013. The target habitats for compensation include dry grey dunes and moist dune valley grassland. Due to the habitat type, the nourished material had to have a special character. The nourishment was carried out according to a special design and initial development of the new area had to follow certain pathways. In order to meet the compensation requirements in time. Careful monitoring is done to assess whether development of the new habitat is taking place in the direction of the desired target habitats. This paper reports on the construction of the new area and on the first years of development and monitoring. The monitoring mainly concerns development of the abiotic landscape elements, geomorphology, groundwater and soils. The lessons learned from this area are discussed in the light of the development of other recent young nature areas in the sandy Dutch delta coast. This gives new insights for coastal management in general in the context of building with nature.     

Climate research and policy advice: scientific and cultural constructions of knowledge

The present paper is a call to cultural sciences for helping climate science to establish a sustainable practice of policy advice concerning man-made climate change.As a climate scientists engaged in communication with stakeholders and the media, mostly in Germany, the author has noticed a notable discrepancy between scientific knowledge about climate change, and the understanding in the public at large, specifically as fostered by the media and some publicly visible climate scientists. In this essay, this discrepancy is analysed to some extent and framed as the presence of two competing types of knowledge, namely a body of knowledge named “cultural construct” and another body of knowledge named “scientific construct” of man-made climate change. The relationship and the dynamics of these two knowledge claims are not well researched. In order to understand the dynamical interaction of the different knowledge claims significant efforts from cultural sciences are needed. Unfortunately, so far these disciplines do not often consider this field. Two examples of useful analyses are presented as examples.     

Decision support in urban water management based on generic scenarios: The example of NoMix technology

Urine source separation (NoMix technology) followed by processing the concentrated nutrient solution has the potential to become a cost-efficient alternative to conventional end-of-pipe nutrient elimination. A choice of processing technologies can only be made for specific scenarios, and there is currently no methodology for analyzing generic situations. In setting up a formalized decision-support methodology (based on STEEPLED analysis), we discuss how to create such generic scenarios, how to couple them with process engineering objectives, how to define the technology requirements, and finally how to produce a realistic subset of technology alternatives. The methodology is tested in five real scenarios. We also touch on the criteria for a final choice of technology taking into account large uncertainties about the performance of real technologies. We conclude that technology development is one of the most important requirements for implementing urine source separation in practice. There is an urgent need to develop cost-efficient processing technologies that satisfy the requirements of stakeholders.     

Sustained treatment: Implications for treatment timescales associated with source‐depletion technologies

Sustained treatment is an emerging concept used to describe enhancements in attenuation capacity after the conclusion of the active treatment period for a given source‐depletion technology. The term includes mechanisms that lead to contaminant transformation or destruction over extended periods of time, such as endogenous biomass decay, slow diffusion of remedial amendments from low‐permeability zones, and the formation of reactive mineral species. This “value‐added” treatment continues after the end of capital expenditures at a site, and it provides additional insight in determining if monitored natural attenuation is a viable long‐term option for a site. This article identifies several sustained treatment mechanisms, examines technology‐specific factors that contribute to sustained treatment, and explores the potential timescales of sustained treatment relative to active treatment. As demonstrated in post‐treatment site data obtained during a comprehensive source‐depletion technology performance survey, enhanced bioremediation is the most promising in promoting sustained treatment, and this beneficial effect can extend for several years due to factors such as slow biomass decay. There is little evidence that other commonly used technologies (thermal treatment, in situ chemical oxidation, surfactant‐enhanced remediation, or cosolvent flushing) result in any significant sustained treatment. An exception would be a cosolvent flushing project where large quantities of biodegradable cosolvent are left in the subsurface at the end of the project, which could result in sustained long‐term dechlorination activity. In the case of in situ chemical oxidation, factors that contribute to a higher incidence of concentration rebound mask any potential sustained treatment effects. © 2011 Wiley Periodicals, Inc.     

Signal Recognition and Hearing Protectors With Normal and Impaired Hearing

Recognition of acoustic signals when perception is subject to interference from noise has already been extensively studied. In this study the influence of hearing protectors (HP) (plugs, muffs) and hearing loss on signal recognition is examined. Different spectrums and levels of the noise are also included. The test results are shown as the masked threshold for the signals heard and identified. In the case of normally hearing subjects a frequency-independent HP (plug) improves hearing performance, while frequency-dependent HP (muffs) tends to worsen it, especially with low-frequency noise. Hearing losses even worsen hearing performance when plugs are worn. Design suggestions are made to optimise signal recognition. Minimum signal-to-noise ratio and the use of HP are discussed.