Search

Environmental flows are now a standard part of sustainable water management globally but are only rarely implemented. One reason may be insufficient engagement of stakeholders and their priority outcomes in the environmental flow-setting process. A recent environmental flow assessment (EFA) in the Kilombero basin of the Rufiji River in Tanzania concentrated on a broad-based investigation of stakeholders' use and perceptions of the ecosystem services provided by the river as a framework for the assessment of flow regimes that would maintain them. The EFA process generally followed the Building Block Methodology but within an enhanced stakeholder engagement framework. Engagement began with the involvement of institutional stakeholders to explain the purpose of the EFA and to elicit their priority outcomes. Extensive interactions with direct-use stakeholders followed to investigate their uses of and priorities for the rivers. Results were used by the EFA specialist team in choosing flow indicators and defining measurable environmental objectives. The specialists then met to reach a consensus of the flow requirements. The EFA results were lastly reported back to stakeholders. During the Kilombero EFA, we learned that stakeholders at all levels have a good awareness of the natural services provided by a healthy river and can contribute to the setting of environmental objectives for the rivers and floodplain. These can be factored into the biophysical assessments of river flows required to maintain habitats, processes, water quality, and biodiversity. It is therefore important to allocate significant resources to stakeholder engagement. It now remains to be seen if enhanced stakeholder engagement, including the increased understanding and capacity built among all stakeholders, will increase support for the implementation of the recommended flows.

The effects of anthropogenic water use play a significant role in determining the hydrological cycle of north India. This paper explores anthropogenic impacts within the regions’ hydrological regime by explicitly including observed human water use behaviour, irrigation infrastructure and the natural environment in the CHANSE (Coupled Human And Natural Systems Environment) socio‐hydrological modelling framework. The model is constrained by observed qualitative and quantitative information collected in the study area, along with climate and socio‐economic variables from additional sources. Four separate scenarios, including business as usual (BAU, representing observed irrigation practices), groundwater irrigation only (where the influence of the canal network is removed), canal irrigation only (where all irrigation water is supplied by diverted surface water) and rainfed only (where all human interventions are removed) are used. Under BAU conditions the modelling framework closely matched observed groundwater levels. Following the removal of the canal network, which forces farmers to rely completely on groundwater for irrigation, water levels decrease, while under a canal only scenario flooding occurs. Under the rainfed only scenario, groundwater levels similar to current business as usual conditions are observed, despite much larger volumes of recharge and discharge entering and leaving the system under BAU practices. While groundwater abstraction alone may lead to aquifer depletion, the conjunctive use of surface and groundwater resources, which includes unintended contributions of canal leakage, create conditions similar to those where no human interventions are present. Here, the importance of suitable water management practices, in maintaining sustainable water resources, are shown. This may include augmenting groundwater resources through managed aquifer recharge and reducing the impacts on aquifer resources through occasional canal water use where possible. The importance of optimal water management practices that highlight trade‐offs between environmental impact and human wellbeing are shown, providing useful information for policy makers, water managers and users.

Flow patterns in the Great Fish River in the Eastern Cape province of South Africa have changed from being seasonal, with predictable no-flow periods during winter, to perennial following the completion of an inter-basin transfer scheme in 1977 to provide a regular supply of irrigation water. Simulium chutteri (Diptera: Simuliidae) consequently became a problem species of pestilential proportions, due to increased flow volumes and current velocities favouring this species. In this study, aquatic invertebrates were sampled from the stones-in-current biotope with a range of current velocities at three sites on the Great Fish River, with a particular focus on pool/rapid areas favouring S. chutteri. The main aim of this paper was to determine whether critical hydraulic thresholds, including current velocity, could be derived for this species. Knowledge of the hydraulic preferences of S. chutteri is a prerequisite for any integrated control programme which combines larvicidal control with flow manipulation. S. chutteri was found to favour the rapids biotope with current velocities in excess of 90 cms−1, with preferences for higher current velocities increasing with life cycle stage. Additional hydraulic variables, at the scale measured in this study, did not correlate with larval densities. There is potential for more effective long-term control of problem populations of larval blackfly in the Great Fish River through further research on the potential for using constructed in-stream vanes to reduce current velocities in rapids of the river at critical periods of the year (July–October), based on flow duration/current velocity relationships. Copyright © 2007 John Wiley & Sons, Ltd.

In this article we review economy class syndrome or travellers' thrombosis as it should be more appropriately described. We review the evidence for and against the existence of this condition. Much of the evidence included in this article has been justifiably criticised but it is the best evidence available to date. We conclude that there is a probable link between thrombosis and long distance travel. However this association is confined to individuals with additional risk factors and fatal pulmonary embolus is very rare. The probable aetiology of this association is prolonged immobilisation in cramped conditions. Other factors are likely to play a minor role. When considering preventative measures, for the majority of individuals the risk is very small. Simple advise can be given with no requirement for additional intervention. Compression stockings should be considered for high-risk patients. In individuals planning prolonged travel with multiple risk factors for thrombosis low dose low molecular weight heparin should be considered. The criteria for defining risk groups remains unclear and we outline our recommendations. There is conflicting evidence with regard to the use of aspirin but considering the latest evidence we do not recommend it.

That hydrolysis of [1]benzopyrano[4,3-b][1]benzopyrylium derivatives 1 includes a double-bond shift giving derivatives 5 of 3-(2-hydroxybenzyl)[1] benzopyran-4-ones has been confirmed. Chromones like 5 are related to the 7H-[1]benzopyrano[3,2-c][1]benzopyrylium cations 9 into which they are transformed by strong acids. The double bond shift occurs in the cations and is mediated not by prototropy but by hydride exchanges via the 6H,7H-[1]benzopyrano[4,3-b][1]benzopyrans 6, thus: 1+6⇌6+1 and 1+6⇌6+9. The equilibria favour the cations 9 which are hydrolysed by water to the chromones 5. Initiation occurs when the cations 1 add water giving the alcohols 2 which reduce them to the catalysts 6 and are themselves oxidised to 6H,7H-[1] benzopyrano[4,3-b][1] benzopyran-7-ones 7.

Bulk milk cooling systems for farm use are described. Data are given for the performance of energy conserving systems, such as in-line precooling of the milk and heat recovery units.