Water quality and water-use conflicts in Lake Taabo (Ivory Coast)

The Lake Taabo (Ivory Coast, Africa) results of the construction of the Taabo dam on the Ban- dama River. The changes in the water level of the 69-km² lake depend on 1) the rainfall linked to alternating dry/wet seasons; 2) the extraction of water for human uses; 3) the discharge of water from the upstream dam and the volumes tur- bined by the Kossou dam; 4) the various an- thropic effects (discharge of untreated waste water from towns and industries, and leaching from agricultural land). The average concentra- tions of nutrients (NH4-N: 1.1 mg/L, NO3-N: 1.62 mg/L, PO4-P: 10 mg/L, SiO2: 15 mg/L) and chlo- rophyll a (from 4.8 to 16.5 μg/L, average 11.4 μg/L) indicates some degree of eutrophication. The cumulated effects that threaten the ecosys- tem (degradation of water quality and eutrophi- cation) are such that they are likely to interfere with various water uses. In a context of growing health and environmental concerns in Africa, this study demonstrates conflicts between dif- ferent uses of this water resource and the urgent need for an appropriate policy including specific monitoring of lake water quality, wastewater control, and a programme to reduce agricultural fertilizers

Temporal patterns in the upstream migration of European eels (Anguilla anguilla) at the Couesnon estuarine dam

The temporal migration patterns of European glass eel Anguilla anguilla at the Couesnon estuarine dam (Mont-Saint-Michel Bay, France)were examined in winter and spring 2004 and 2005. The dam which is located close to the river mouth constitutes a major obstacle for upstreammigrating glass eels. The migration was observed at different temporal scales, from within individual tides to complete tidal cycles between successive spring tides. The maximum number of glass eels arrived downstream of the dam at the beginning and in the middle of the flood tide. Glass eels migrated through the dam openings preferentially from the middle of the flood to the beginning of the ebb tide. Eel densities were highest during the second tide of each tide cycle that arrived at the estuarine dam and when the difference in water level between upstream and downstream of the dam was greatest, particularly at the end of the flood. Analysis of the influence of each environmental factor provided a good prediction of the glass eel recruitment peaks and, therefore, of the most favourable temporal windows for their migration. The water level and temperature were the most important environmental factors. These results provide the information needed for a dam-management program that is compatible with glass eel migration

Proof of concept for an innovative pump fishway design to move fish upstream over dams

Reversing worldwide declines in freshwater fish while making sustainable use of water resources will require effective and economical fishways to restore fish migrations. Mitigation of barrier effects at dams and weirs is too often impeded by poor fishway performance and high costs, so that many fish migrations continue to be obstructed. Improved and less-costly designs are urgently needed. Our innovative pump fishway concept combines fish-behaviour insights, proved fishways techniques and aquaculture’s pumping methods for safe upstream transport of living fish. We ran a series of experimental trials using several scale-model fishway designs with young, hatchery-bred fish. Our horizontal-cylinder design successfully combined volitional-passage functions of existing fishways with non-volitional transport in a conduit carrying pumped water. Several key principles of fish behaviour in fishways led to design improvements: disturbed fish often seek refuge at depth; fishes’ escape reactions strongly motivate swimming into flows; and curved structures aid passage by reducing delays. Replicated trials finally produced an average of 98% successful passage, within brief cycling periods. The pump fishway concept offers potential for effective upstream fish passage at new and existing sites \u3e~2m high, with low construction and maintenance costs and highly adaptable operation in variable flow regimes. Development beyond the concept-trial phase is now a priority

A GHG Metric Methodology to Assess Onsite Buildings Non-Potable Water System for Outdoor Landscape Use

This paper documents a water:energy greenhouse gas (GHG) metric methodology for a decentralized non-potable water system that was developed as part of a Professional Doctorate in Engineering (DEng) research project by the first author. The project identified the need to investigate the challenges in changing the use of potable water to recycled water for landscape irrigation (LI) and for water features (WFs) at a medical facility case study (MFCS) in Abu Dhabi (AD) (the capital city of the United Arab Emirates (UAE). The drivers for the research project were based on the need for AD to decrease desalinated potable water as well as reduce the environmental impact and operational costs associated with the processing and use of desalinated water. Thus, the aim of the research discussed and presented in this paper was to measure the impact of using recycled and onsite non-potable water sources at the MFCS to alleviate the use of desalinated potable water and reduce associated energy consumption, operational costs, and GHG emissions (latterly in terms of carbon dioxide equivalent (CO2e), for LI and WFs. The analysis of three case scenarios at the MFCS compared different approaches to alleviate energy use, costs, and GHG impacts for the use of recycled water in LI and WFs against a baseline. The findings led to a proposed sustainable water conservation and reuse (SWC) strategy, which helped save 50% desalinated potable water for LI use by soil improvement, building water system audits, and alternate non-potable water reuse. The recommendations for this paper are to develop a SWC strategy forming the basis for a water protocol by the competent authority for regional medical facilities including an assessment methodology for building decentralized non-potable water systems to measure their energy, GHG emissions and financial impact

Managing Malaysian water resources development

Water is a gift of God and Malaysia is rich in water resources. Water development has fueled socio-economic development of the country during the past decades.Dams and thousands of kilometres of pipes and canals divert water from the rivers to sustain domestic, industrial and agricultural needs. Lately, the water situation for the country has changed from one of relative abundance to one of relative scarcity.The population growth and the expansion in urbanisation, industrialisation and irrigated agriculture are imposing rapidly growing demands and pressure on the water resources, besides contributing to the rising water pollution. Water management is becoming increasingly comprehensive and complicated due to larger concentrations of population, commercial activities and industries around the cities and towns, increasing water consumption, increasing water pollution, increasing land use conflicts and climate changes. At the same time, development of new water resources to meet the ever increasing water demand is facing opposition from the environmentalists. Therefore, the preferred water supply management approach,whereby new supply sources are tapped to meet increasing demand should be replaced by water demand management approach, whereby efforts are directed towards managing the demand to keep it within available supply sources. Water demand management monitors and improves the efficiency of the supply system and all water users need to adjust their needs to the available water. The way forward to a prosperous and sustainable future is by keeping development to a level that is kept within the carrying capacity of the river basin while protecting and restoring the environment. As such, the water demand management should be practised within the broader context of integrated water resources management (IWRM). IWRM is an approach towards integrating and effectively coordinating policies, programs and practices addressing the water related issues which takes into consideration the aspects of socio-economic development and the conservation of the environment. The comprehensive management of water resources will cover three components namely,the management of water as a precious resource, the management of wastewater and water pollution, and the management of water related hazards such as floods, droughts and landslides. Whilst water related problems are essentially local issues,the solutions to such problems must be tackled from a broader perspective. These will require improved professional capability, and increased financial, legislative,managerial and political capacity

Fresh Water and Smarter Growth: Restoring Healthy Land-water Connections

The paper describes water resources in the United States, discusses the principles of the land-water connection, outlines the current regulatory framework, and explains the impact of climate change. It also introduces the concept of low impact development while providing examples, and highlights how funders are having an impact on sustainable water management. With bibliographical references

Rice Center focuses on restoring wetlands

Halfway between Richmond and Williamsburg, where Kimages Creek flows into the James River, lies the Inger and Walter Rice Center for Environmental Life Sciences. A restoration project aims to return the area to its original state as a wetland. The project began by removing a dam that had been blocking the flow of Kimages Creek since 1927

Benefit Estimation of Water Quality Improvements in Bagmati River Using Choice Modeling

Environmental Economics and Policy,