March 1993
WATER FOR AGRICULTURAL DEVELOPMENT: OPPORTUNITIES AND CONSTRAINTS (pp. 3-12)
Asit K. Biswas, 76 Woodstock Close, Oxford, UK and International Development Centre, University, of Oxford, UK
Abstract: Globally around 70% of all water used is for agricultural development. Thus, if the world’s food crisis is to be successfully resolved, enough water of appropriate quantity and quality will be necessary. Water scarcity is already a serious issue in many arid and semi-arid countries, and the problem is likely to intensify significantly in the future. Agriculture also affects water quality in many ways. The paper analyses the present’ status of the impacts of use of pesticides and nitrate fertilizers from different parts of the world.
URBAN AND AGRICULTURAL COMPETITION FOR WATER, AND WATER REUSE (pp. 13-25)
Herman Bouwer, US Water Conservation Laboratory, Agricultural Research Service, US Department of Agriculture, Phoen, USA
Abstract: Competition for water can be resolved by construction of more facilities for storing water in wet years for use in dry years, by weather modification, watershed management, urban and agricultural water conservation, reuse of sewage effluent and other wastewater, desalination of saline water, water banking and transfer of water rights or other changes in water use. Reuse of wastewater requires treatment so that the water meets the quality requirements for the intended reuse. Groundwater recharge and recovery can play an important role in the treatment and storage of wastewater for reuse—agricultural, urban, and industrial, as well as potable. Often, water shortages are only shortages of cheap and abundant water, and competition problems can be resolved by good planning and management if the public is willing to pay the price and to accept changes in water use.
THE LABOUR ASPECT IN THE CHOICE OF IRRIGATION TECHNOLOGY IN TORRE PACHECO, SOUTH-EAST SPAIN (pp. 27-37)
Wim Kloezen and Maarten Van Bentum, Department of Irrigation and Soil and Water Conservation Agricultural University Wageningen, The Netherlands
Abstract: This article discusses the choice of irrigation methods in relation to labour. For three types of irrigation methods—trickle irrigation, traditional furrow irrigation and modern furrow irrigation—the technical characteristics and the labour-saving potentials are analysed and related to the labour situation of four groups of farm enterprises. Conclusions are drawn on the need for irrigation engineers to develop a better understanding of the labour parameters of irrigation methods.
POLLUTANT LOADINGS: ACCURACY CRITERIA FOR RIVER BASIN MANAGEMENT AND WATER QUALITY ASSESSMENT (pp. 39-50)
E.D. Ongley, International Programmes Group, National Water Research Institute, Canada Centre for Inland Waters, Burlington, Canada
Abstract: The loading concept produces approximate values that are useful for managing tributary and point-source inputs of deleterious substances to receiving water bodies. River loadings are subject to large measurement inaccuracies and scientific uncertainties. Simulation, using random numbers, produces calculated loads that are within the error of fluxes obtained from typical river sampling programmes. Data for which analytical quality assurance is unknown may be suitable for loadings purposes. There may be more cost-effective ways of obtaining data for loadings purposes. Agencies that focus on analytical accuracy may be misstating their confidence in making management judgement based on loadings.
HYDROLOGIC SIMULATION OF RESERVOIR STORAGE REALLOCATIONS (pp. 51-64)
Ralph A. Wurbsa and Patrick E. Carriereb
aCivil Engineering Department, Texas A&M University College Station, Texas, USA; bCivil Engineering Department, Texas A&I University, Kingsville, Texas, USA
Abstract: Operational modifications at existing reservoir projects can be quite beneficial in responding to changing conditions and intensifying demands on limited resources. Computer simulation models are readily available for analysing reservoir operations. A case study is presented which illustrates a general simulation modelling approach for evaluating reallocation of storage capacity in existing reservoir systems. A set of generalized simulation models, developed by the USACE Hydrologic Engineering Center, are used with monthly hydrologic data.
MANAGEMENT OF LIMITED WATER RESOURCES IN HONG KONG (pp. 65-73)
K.W. Chau, Department of Civil & Structural Engineering, Hong Kong Polytechnic, Hung Horn, Kowloon, Hong Kong
Abstract: The topography of Hong Kong is very complex and there are no major rivers or natural lakes in the territory. The rapid increase in population—mainly caused by the influx of immigrants from across the border—and the territory’s rapid economic strides have led to an ever increasing demand for water. As such, water rationing is a recurrent problem which causes many economic as well as sanitary risks. This paper summarises the basic hydrological features of the territory and highlights the various approaches adopted to minimize the damages due to the limitation of water resources in Hong Kong.
MONITORING AND EVALUATION OF NIGERIA’S IRRIGATION SYSTEMS: THE CASE OF THE BAKOLORI IRRIGATION PROJECT (pp. 75-85)
Are Kolawole, Centre for Social and Economic Research, Ahmadu Bello University, Zaria, Nigeria
Abstract: One of the major banes of water resources development projects in Nigeria is lack of effective monitoring and evaluation. This apparent neglect has resulted in the inability to complete projects within the stipulated period, escalation of costs, poor design and construction works, and inevitably poor performance. This article reports the result of a diagnostic survey of the Bakolori Irrigation Project (BIP), one of the most controversial schemes in Nigeria. It is suggested that project monitoring and evaluation should be made compulsory on all irrigation projects in Nigeria, if they are to make any meaningful beneficial impact on the rural development process.
CARRYING CAPACITY AND VULNERABILITY OF FOUR ASIAN LAKES: A COMPARATIVE STUDY (pp. 87-107)
Takehiko Fukushima and Hideo Harasawa, National Institute for Environmental Studies, Tsukuba, Japan
Abstract: To present axes for evaluating the water resources, lake environment and water use in a lake and its watershed, a comparative study was done for four East Asian lakes; lake Kasumigaura (Japan), Lake Laguna (Philippines), Lake Songkhla (Thailand) and Lake Dianchi (China). Two axes were then determined from the relationship between: (1) water use and water supply rate, and (2) water use and water quality. To clarify the meanings ‘carrying capacity’ and ‘vulnerability’, the maximum population density in the lake basin and total nitrogen concentration in the lake water were calculated and discussed to decide the direction of environmentally sound management of the drainage basin.