Effects of water use and management practices on the environment

Today perhaps half of economically available freshwater is used to satisfy human demands—twice what it was only 35 years ago [Young et al. Uncertainties relating to human responses to climate change and planning in other sectors e.

In addition to the need to allocate water for the maintenance of ecosystems, we will need to eliminate the discharges of human and industrial wastewaters that are being discharged into the environment often without concern for their effects on ecosystems.

Effects of water use and management practices on the environment

Liquid waste disposal Disposal of liquid wastes from municipal wastewater effluents, sewage sludge, industrial effluents and sludges, wastewater from home septic systems; especially disposal on agricultural land, and legal or illegal dumping in watercourses. Climate change thus prompts a need to systematically develop multiple integrated objectives for EWM that incorporate socio-economic, cultural and ecological aspects Dunlop et al. Conventional approaches to EMW have often focused on iconic wetlands Swirepik et al. While errors may have been made in the past, particularly with respect to the environmental and social impacts of large dams, the World Commission on Large Dams [UNEP, ] has provided a very useful guide to avoid these errors in the future. In the past, we have made decisions regarding the management of our water resources that have not always helped us become more secure or sustainable. We have overdrawn groundwater aquifers; polluted many, if not most of our water bodies including estuaries, coastal zones and even oceans; and degraded ecosystems. Adapting EWM A wide variety of methodologies and frameworks have been developed to guide environmental flows and EWM, ranging from those which focus on calculating local flow regime requirements associated with specific targets e. Aquaculture is now recognised as a major problem in freshwater, estuarine and coastal environments, leading to eutrophication and ecosystem damage. There is no escape from the fact that the need and demand for finite and vulnerable water will continue to expand and so will competition for it. Capon and Capon, Sediment, nutrients and pesticides occupy the first four categories and are significantly associated with agriculture. In comparison, control of non-point sources, especially in agriculture, has been by education, promotion of appropriate management practices and modification of land use. So why is there food insecurity in our world?

To meet the nutritional needs of this additional population, we should consider the amount of water that is consumed in the production of different goods and, in particular, energy and food. Here, we discuss major challenges to environmental flows and EWM under a changing climate as well as the adaptations needed to meet these for both environmental and societal benefit.

The range and relative complexity of agricultural non-point source pollution are illustrated in Figure 1. Poff also calls for a more robust and dynamic predictive science involving time-varying flow characterizations, and more use of process e.

Access to safe water and sufficient food is still a dream for almost a billion people.

Investments made in water infrastructure such as dams , storage, and conveyance facilities represent huge stocks of physical capital. Expansion and construction of environmental water delivery works e. We depend on water not only for life itself, but indeed for our economic wellbeing as well. Climate change in particular necessitates a revision of EWM, especially as it represents, in itself, an important strategy in society's broader adaptation to climate change by promoting the protection and augmentation of increasingly critical ecosystem services Capon and Bunn, The Global Risk Perception Survey conducted among recognized experts by the World Economic Forum reports that the highest level of societal impact over the next 10 years will be from water crises. Our planet no longer functions in the way it once did. Recommendations are made on evaluation techniques and control measures.

Nearly every hydrologic method introduced prior to will have been adapted to account for the increased uncertainty and nonstationarity which have become the central challenges of our profession.

Additionally, real-time data may also be required to capture rapid changes in environmental conditions so that interventions and management practices can be adapted accordingly in a timely manner Wilby et al. Consequently, the selection of indicators used to monitor EWM will probably need to be adapted in light of climate change given likely revisions of objectives and targets.

The data problem Second only to availability of drinking water, access to food supply is the greatest priority.

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Chapter 1: Introduction to agricultural water pollution