[...]... that agriculture is the single largest user of freshwater resources, using a global average of 70% of all surface water supplies Except for water lost through evapotranspiration, agricultural water is recycled back to surface water and/or groundwater However, agriculture is both cause and victim of water pollution It is a cause through its discharge of pollutants and sediment to surface and/or groundwater,.. .Control of water pollution from agriculture 1 Chapter 1 Introduction to agricultural water pollution Second only to availability of drinking water, access to food supply is the greatest priority Hence, agriculture is a dominant component of the global economy While mechanization of farming in many countries has resulted in a dramatic fall in the proportion of population working in agriculture, ... Observations from space described the transition of Madagascar from an island of green in a sea of blue, to an island of brown in a sea of red (sediment) • - 100% 10% nearly 100% 60-70% of fringing reefs Control of water pollution from agriculture 21 that the central portion of the river basin is now dominated by sediment deposition This has resulted in serious disruption of river transportation, and clogs hydraulic... highlighted below: q Five million people die annually from water- borne diseases Control of water pollution from agriculture q Ecosystem dysfunction and loss of biodiversity q Contamination of marine ecosystems from land-based activities q Contamination of groundwater resources q 3 Global contamination by persistent organic pollutants Experts predict that, because pollution can no longer be remedied by dilution... outlines the classes of non-point sources and their relative contributions to pollution loadings Agriculture is only one of a variety of causes of non-point sources of pollution, however it is generally regarded as the largest contributor of pollutants of all the categories Introduction to agricultural water pollution 6 FIGURE 1 Hierarchial complexity of agriculturally-related water quality problems... disposal of sewage from human settlements and of manure produced by intensive livestock breeding • minimization of adverse effects from agricultural chemicals by use of integrated pest management • education of communities about the pollution impacts of the use of fertilizers and chemicals on water quality and food safety This publication deals specifically with the role of agriculture in the field of freshwater... source of phosphorus compounds and sediment The European Community has responded with Directive (91/676/EEC) on “Protection of waters against pollution by nitrates from agricultural sources” The situation in France has resulted in the formation of an “Advisory Committee for the Reduction of Water Pollution by Nitrates and Phosphates of Agricultural Origin” under the authorities of the Ministry of Agriculture. .. nitrate) Clear cutting Erosion of land, leading to high levels of turbidity in rivers, siltation of bottom habitat, etc Disruption and change of hydrologic regime, often with loss of perennial streams; causes public health problems due to loss of potable water Disruption of hydrologic regime, often with increased surface runoff and decreased groundwater recharge; affects surface water by decreasing flow... purposes Control of water pollution from agriculture 19 Chapter 2 Pollution by sediments Although agriculture contributes to a wide range of water quality problems, anthropogenic erosion and sedimentation is a global issue that tends to be primarily associated with agriculture While there are no global figures, it is probable that agriculture, in the broadest context, is responsible for much of the global... adversely affect water quality so that subsequent uses of water for different purposes are not impaired.” Introduction to agricultural water pollution 2 Sagardoy (FAO, 1993a) summarized the action items for agriculture in the field of water quality as: • establishment and operation of cost-effective water quality monitoring systems for agricultural water uses • prevention of adverse effects of agricultural . Centre for Inland Waters and Dr David Swain of the University of Guelph. Control of water pollution from agriculture v Contents Page 1. I NTRODUCTION TO AGRICULTURAL WATER POLLUTION 1 Water quality. Demand Control of water pollution from agriculture 5 N ON - POINT SOURCE POLLUTION DEFINED Non-point source water pollution, once known as “diffuse” source pollution, arises from a broad group of. health dimensions of the global freshwater quality problem are highlighted below: q Five million people die annually from water- borne diseases. Control of water pollution from agriculture 3 q