Nautical safety and efficiency: simulation and reality

The paper deals with training and research using maritime simulation techniques to provide cost-effective and safe solutions to maritime transportation problems. In order to reduce the probability of accidents, training and research is required in which the human factors are fully taken into account.     

Insecticide pollution of Indian rivers

Summary Rivers are the main source of water in India, and are particularly used for agricultural irrigation and drinking water supply. As most of the rivers pass through agricultural fields, they are subject to contamination with the different insecticides used for crop protection. Residues of persistent organochlorines, which are still used in large quantities in India, are found in water from many Indian rivers. In certain rivers, the concentrations of DDT, aldrin and heptachlor are often present in excess of their guideline limits. Although the concentration level of gamma-HCH is well below the guideline limit, the accumulation of the carcinogenic beta isomer is a matter of great concern. A few organophosphorus insecticides have also been detected in river water. Recently, some organochlorine insecticides have been banned from use in India. The use of new, readily biodegradable insecticides and biocides in agriculture and public health programmes offers some optimism.Drs Satya P. Mohapatia, Vijay T. Gajbhiye and Narendra R. Agnihotri all work within the Division of Agricultural Chemicals at the above address. Dr Manju Raina is employed by the Ganga Project Directorate of the Ministry of Environment and Forests, New Delhi 11003, India.     

An approach for analysing the potential for material efficiency improvement

Material efficiency improvement saves energy and reduces the consumption of primary resources and reduces the volume of waste. In this article an approach for analysing the potential for material efficiency improvement is proposed and discussed. In this approach the product functions performed by the materials and various improvement measures are taken into account. The potential for material saving and associated energy saving is assessed and evaluated economically. In this paper the approach is tested in an analysis of the potential for material efficiency improvement with respect to plastic packaging in the Netherlands. The technical reduction potential is found to be 34 ± 7% (157 ± 30 ktonne virgin plastics). Realization of this potential would improve the energy efficiency of the lifecycle of plastic packaging by 31% (10 PJ in 1988). From our study we conclude that our approach can indeed be used to investigate the potential for material efficiency improvement. However, a reliable technical and particularly an economical assessment of reduction measures cannot be made until more detailed data become available.     

SOCIAL IMPLICATIONS OF SEVERE SUSTAINED DROUGHT CASE STUDIES IN CALIFORNIA AND COLORADO1

ABSTRACT: Survey data collected in the San Joaquin Valley of southern California and the Grand Valley of western Colorado reveal that residents of both areas believe that a severe sustained drought is likely to occur within the next 20–25 years and that their communities would be seriously impacted by such an event. Although a severe sustained drought affecting the Colorado River Basin would cause major economic and social disruptions in these and other communities, residents express little support for water management alternatives that would require significant shifts in economic development activities or in water use and allocation patterns. In particular, residents of these areas express little support for strategies such as construction and growth moratoriums, mandatory water conservation programs, water transfers from low-to high-population areas, water marketing, or reallocations of water from agricultural to municipal/industrial uses. This rejection of water management strategies that would require a departure from “business as usual” with respect to water use and allocations severely restricts the capacity of these and similar communities to respond effectively should a severe sustained drought occur.     

A FIELD TECHNIQUE FOR WEIGHING BEDLOAD SAMPLES1

ABSTRACT: A technique for weighing bedload samples that was developed for laboratory use has been modified for field application. The technique involves determining the submerged weight of bedload samples as they are collected. The submerged weights are converted to dry weights from a knowledge of the specific gravity of the bedload material. The technique makes bedload transport data available immediately and eliminates costly and time-consuming steps involved with saving samples for laboratory analysis. Only samples designated for particle-size or other lab analyses need to be saved.     

SIMULATION OF HERBICIDE CONCENTRATIONS IN STORMFLOW FROM FORESTED WATERSHEDS1

The breakpoint rainfall hydrology and pesticide options of the field scale model CREAMS (Chemicals, Runoff, and Erosion from Agricultural Management Systems) were used to predict average concentrations of hexazinone [3 cyclohexyl-6-(dimethyl-amino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] in stormflow from four forested watersheds in the upper Piedmont region of Georgia. Predicted concentrations were compared with measured concentrations recorded over a 13-month period. CREAMS accurately predicted hexazinone concetrations in the initial stormflow events which also contained the highest concentrations. The model underestimated the hexazinone concentrations in stormflow two months and greater following pesticide application. In a companion study, the daily rainfall option of the CREAMS model was used to evaluate the reltive risk associated with the maximum expected concentration of hexazinone, bromacil (5-bromo-3 sec-butyl-6 methyuracil), picloram (4-amino-3,5,6 trichloropicolinic acid), dicamba (3,6-dichloro-0-anisic acid), and triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} in stormflow from small forested watersheds. The model predicted the following order of potential residue appearance in stormflow: bromacil>triclopyr>hexazinone>picloram>dicamba. Subsurface movement of residues via interflow and deep leaching losses are not simulated by the version of CREAMS used in these studies.     

Insect habitat management in pasture systems

Two important habitat management strategies in pasture systems involve controlled burning and effective grazing manipulation schemes to maintain native climax grassland vegetation These climax grasslands have historically suffered less insect pest pressure than imported systems However, these types of grasslands are difficult to reestablish after relatively severe disruption by man Also, the proper diversity and stability is difficult to capture in developing imported systems. Imported pastures can exhibit substantial yields per land unit but are often composed of vegetation that rapidly mines nutrients stored by the native vegetation, and often need considerable inputs of fossil fuel, manufactured fertilizers and pesticides, because they are or become very susceptible to pestiferous insects. Habitat manipulation efforts can be effective in regulating forage pest populations below economic levels in imported pasture systems Such efforts include: 1) land use (coupled with plant diversity, grazing, and harvest manipulations), 2) sanitation (including controlled burning), 3) planting dates and harvest times (including grazing manipulations), 4) tillage methods, 5) fertilization, 6) trap crops, 7) water management, and 8) fire management for insect pest suppression and augmentation of natural enemies.     

From the Editors

Editorial Introduction

From the Editors     

Mass movements and conservation management in Malta

Mass movements at an environmentally sensitive but very popular leisure site in Malta were investigated in order to establish whether they were naturally occurring or whether they might in some way have resulted from the chronic long-term degradation of the site. Field surveys of the slopes were undertaken and physical and geotechnical properties of the Maltese Blue Clay Formation, which forms the slopes, were determined from laboratory analysis of samples. Slope stability was analysed using the infinite slope model; analysis of two 1996 mudflows indicates that these mass movements are natural processes. A landslide hazard analysis based on this finding suggested that whilst future mudflows constitute a small hazard, the risk of harm arising from them is even smaller. The implications of this for conservation management of the site are important, given the objective of restoring and then maintaining a natural ecological environment at the site. The mudflows are integral components of this natural environment, shaping the landscape and the ecological communities. The provision of information to visitors constitutes a valuable education and management tool that should further reduce the risk of harm and promote responsible recreational use of the site. However, it is essential that managers understand the nature of all relevant components of an environmentally sensitive site, in order that appropriate management strategies are devised. In the case discussed, these might include avoiding unnecessary future intervention on the clay slopes.