As elsewhere in the world, anticipated population growth in the next 50 years, climate change and reduced surface water availability, water “productivity”, or water use efficiency (WUE) must continue to improve in the American Southwest. Beyond the intrinsic value to life, water takes on additional value as food and fiber, fisheries and ecosystem benefits that are linked such that emphasis of one over the other benefit often results in losses neglected in the past. For example, development of upstream water storage exchanges downstream fisheries and ecosystems benefits for crop production, while reservoir evaporation losses further reduce possible downstream resource values. Unlike WUE improvements in the municipal sector, possible through metering and technological changes in flow devices and washing appliances, improved WUE in crop production is hampered by unidentified achievable water use targets. In terms of water use, the dominant crops in the Southwest are alfalfa and sudangrass hay and cotton lint production. The water use characteristics, average planted areas and yields, and water values are examined for these crops in Arizona, California and Idaho to determine possible target WUEs and assess possible on-farm water savings in the region based on actual production information from 1988-2000. Field-based WUEs of 1.7kg/ha-mm for alfalfa and sudangrass hay and pima cotton, and 2.1kg/ha-mm for upland cotton lint production appear to be practical target values from which to determine appropriate water use. Based on FAO #56 estimated and yield-based water use for these three crops, possible water savings of up to 50% exist with the greatest water savings potential in desert regions where current water values as hay or lint crops are low relative to other regions. Such high water savings in the desert region are unlikely and targets of 20-30% corroborated by research trials, are more likely. The greatest water values and least possible water savings occur in the southern San Joaquin Valley, CA where the combination of relatively high evapotranspiration (ET) and some rainfall occur. This research is a starting point for assessing water use/savings at the field scale for hay and cotton productions and should be extended to other crops. Additional work may also be required considering water savings at the district scale associated with the water distribution systems.
Water and other natural resources of the Bung Boraphet Wetland in Thailand have been under increasing pressure from over-exploitation. Sustainable management and ‘wise-use’ of the Wetland's resources require achieving a balance between economic exploitation and conservation. Scientifically based decision support tools are vital to gain better insights into the complex interactions between the large wetland system, its contributing catchment and floodplain, and then pave the way for planning effective long-term management. This paper presents a summary of several decision support tools that we developed for Bung Boraphet. The tools are: (a) Water budget predictive model, (b) Land-use analysis using satellite imagery, and (c) Database linked Geographic Information System. From a review of literature and field studies, we identified the factors that have the most serious impacts on long-term sustainability of Bung Boraphet. We also conducted field studies to collect primary data on hydrological parameters of the lake between December 2002 and May 2006. These and available secondary data were then used to develop a model for the daily water budget of the Wetland. Model calculations and observed water levels are highly correlated for this period, proving the veracity of the model. Evaporation loss of water is a critical factor during the dry seasons (∼41% loss), as is extraction for irrigated rice grown in encroached areas around the lake (∼55% loss). The modeling tool allows the analysis of different water use scenarios. For instance, the model forecasts that even if the weir height is raised by 0.5m to a level of +24.5m (MSL), as has been suggested by some stakeholders, irrigation water abstraction has to be reduced by 35% of the current consumption to maintain the recommended minimum water level (+23m, MSL) for a sustainable fishery. Insights into land use changes in the surrounding catchment and lake were gained by a series of Landsat 5 satellite images. A comparison of images shows that between 1993 and 2003, the irrigated area surrounding the lake doubled. At the same time, the submerged and emergent vegetation in the lake declined by 50%. The database linked GIS, which we developed, includes meteorological data and primary and secondary data on hydrology, water quality and biodiversity of the lake and its catchments, and covers the main rivers and their tributaries. Information from applying the decision support tools has stimulated discussions with key stakeholders, identifying the ‘wetland values’ that need protection, and the economic, environmental and social goals that need to be met by a future plan of management. As discussed in this paper, we have made a significant difference in the nature of the discourse on the management of Bung Boraphet by demonstrating the value of basing wetland management decisions on scientific information. The POM, which is being developed, is expected to receive multiple stakeholder support, so that Bung Boraphet's resources can be sustained for use by present and future generations.
Although Japan is well known as an industrialized country rather than an agricultural one, agriculture is treated as a very important sector from cultural and environmental perspectives. Only 15% of Japan's land is suitable for cultivation, but the agricultural economy is highly subsidized and protected. With per unit area crop yields among the highest in the world, the agriculture sector still dominates the major part of water use (65%) in Japan followed by domestic and industrial uses (20% and 15%, respectively). Like many other monsoon Asian countries, rice is the staple food in Japan, and paddy fields and terraces are often referred to as the country's cultural and environmental indicators. This paper outlines the conditions of water resources and their relations to some major agro-environmental issues in Japan as well as focuses on a case study research related to soil erosion in the southernmost part (Okinawa Island) of the country. The case study results show that if farmland soil is mixed with the plant residues and treated for 3 to 4 months under natural conditions, the hydraulic conductivity of the soil can be improved and eventually reduce the amount of soil erosion.
Utilization of water resources in Bangladesh depends on their availability and conservation depends on storability subject to upstream conditions of the lower riparian countries. Bangladesh is located at the lower riparian region of the three major internationally famous rivers, namely the Ganges, the Brahmaputra and the Meghna. Management and development of the water resources of the country is completely dependent on the availability of water from the transboundary rivers and annual distribution of rainfall. It has been recognized that Bangladesh experiences water shortages in the dry season and water abundance in the wet season, which significantly disrupt the agro-environmental practices and socio-economic activities of the country. To address the problems encountered due to water shortage or abundance, cooperation among the co-basin countries is needed, as well as proper utilization and conservation of water resources. Agro-environmental education now should focus on these issues with the perspective of Bangladesh as well as the global aspects. This paper describes the problems of water resources management and development, utilization and conservation options based on available data and information in the context of Bangladesh and possible remedial measures to address and overcome the problems.
This paper highlights the importance of water and water resources in the Philippines, the oil spill in Guimaras Island, the super typhoon “Milenyo” (Millenium), and the significant role of environmental engineering education in water resources conservation and wastewater management.
Afghanistan is a landlocked country in Central Asia having arid and semi-arid climates with precipitation from 75 mm per year in the plain area to 1,170 mm in the highland area. Forests cover only 2% of the country and deforestation is progressing rapidly. If precautionary measures are not taken in 15 years the country will have little forest. To measure natural resources of the country, the government established 31 stations to collect meteorological information and 140 stations to record water conditions in different locations of the country. Out of 140 water stations, 40 were selected for sediment transport measurement. Water is a precious material for human beings with different uses such as for domestic use, industrial use and agricultural production is increasing. Water utilization in Afghanistan is mostly for agriculture and approximately 85% of the country's crops are produced under irrigation systems. Irrigation systems in Afghanistan use mostly traditional methods and distribute water in traditional ways throughout the country with 84.6% of irrigation water being tapped from rivers. Water from springs and Karezes make up 7.9% and 7% of irrigation water, respectively. A small amount (0.5%) of water is tapped from Arhats (dug wells). Due to 25 years conflict in Afghanistan all infrastructures including irrigation related structures have been damaged or completely destroyed. Since 1980 there is no information about water resources in the country. On the other side the country has suffered from continuous drought for the last six years. Ground water levels have dropped considerably and affected Karezes to be dry or have reduced water. All reports related to water resources have been lost during the 25 years of conflict. After the new government was elected in 2001, the government gave first priorities to security and communication system of the country and rebuilt 2,500km of pre-war paved highways. Less work on rehabilitation of natural resources has been done so far. As per reports prepared by FAO and the Ministry of Water and Power under the Afghan government, the total annual [DT1] precipitation in the country is 180,000 million m3 (150,000 million m3 from snow and 30,000 million m3 from rain). Meanwhile the total discharge of all rivers is 84,000 million m3 (47%) of the total precipitation in the country. A total of 12% of the land in the country is arable, whereas only 50% of this area is irrigated per year due to shortages of water for irrigation and the other 50% will be irrigated next year. Out of total discharge produced in the country, only 55,000 million m3 (65%) is used within the country. The remaining leaves the country. According to a Ministry of Water and Power report, a total of 2,000 million M3 is used for domestic water supply. There are a limited number of reservoirs to store water for irrigation and power generation. The government must develop a long-term strategy to manage water resources and reduce the effects of drought on agriculture. The strategy should focus on increasing water capital and making better use of water. The strategy should include (i) water harvesting and watershed management, more water reservoirs (small and large), (ii) effective control of ground water utilization, (iii) better information system on water availability, (iv) elimination of unsustainable land use practices, (v) improved intake structures and corresponding on-farm water management, (vi) management transfer of state owned schemes, (vii) extension of the irrigated command area. The geographical situation in the country is where water is available there is not enough land for irrigation and where land is available there is no water to fulfill the irrigation requirements.
India is facing increasing water stress due to population growth, increase in water demand, vulnerability from climate change and deterioration in water quality from domestic as well as industrial and agricultural pollution loads. India occupies about 2.45% of the world area and has a 5% share of the global fresh water resources and with this share of vital natural resources approximately 16.87% of the world population is to be catered. Currently the population of India is a little over 1 billion and it is expected to reach a figure of approximately 1.5 billion by the year 2050. The water availability per capita per year at present is 1730.6 CM (m3) and has almost reached to water stressed (<1700 CM) conditions. Despite the tremendous economic development and growth of industries and service sectors, the livelihood of approximately 68% of the Indian population depends on agriculture directly or indirectly. More than 70% of its population lives in rural areas although there is an increasing trend of urbanization in the last two decades. Irrigation water accounts for approximately 90% of the total utilization of water resources. India stands at a crossroads in institutional options for natural resources management at the local and village levels. The emphasis on future options like watershed development through participatory approaches coupled with sustainability issues is now widely recognized as a potential approach for vitalizing the rural economy. Climate variability in India in terms of rainfall and temperature has noticeable spatial and temporal variations. Even after achieving full irrigation potential from surface and sub-surface water resources, a major portion of cultivated area shall remains rainfed. Furthermore, the conditions may deteriorate with severity of droughts and intensity of flash floods under a climate change scenario. In this article different measures for soil moisture conservation through rainwater harvesting on a watershed basis in problematic Laterite, coastal saline and hill zones of West Bengal State of India are discussed. Although in recent years, both Government and Non-Government Organizations have stepped up their efforts in water conservation by rainwater harvesting on a watershed basis through a participatory approach, the Government of India's Commitment to Participatory Irrigation Management (PIM) with the help of Water Users Associations (WUAs) needs to be strengthened through adoption of a framework from the state level down to the village level. An attempt is made in this article to highlight some key factors in the structural framework as well as in the operation domain of PIM involving WUA from the Indian perspective.
Problems with water resources and water supplies are found in nearly every country of the world. China is one of 13 countries that face very serious conditions in water resource shortages. Water resources must be saved, conserved and well managed, then water supplies will be sustainable. Hydro-engineering and ecosystem interactions must be considered when constructing systems for water resources. Cooperation, experiences and funds are basic aspects for water resources management.