CPWF Basin Focal Point Working Paper Series
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Item Water-use accounts in CPWF basins: Simple water-use accounting of the Karkheh Basin(Working Paper, 2010) Kirby, M.; Mainuddin, M.; Ahmad, M.; Gamage, M.S.D.Nilantha; Thomas, M.; Eastham, JudyThis paper applies the principles of water-use accounts, to the Karkheh River basin in Iran. The northern part of the Basin where the Karkheh and its tributaries rise is mountainous, cooler, and wetter. The River spills out on to the hotter, lower semi-arid plains at its southern end. Precipitation, mainly in winter, varies from 400-500 mm in the upper part of the Basin falling to about 230 mm in the lower reaches. Total water use exceeds rainfall by about 14%, the difference is assumed to be largely pumped groundwater in the upper and middle parts of the basin. Grassland is the most extensive land use and uses about 50% of the total available water. Irrigation, although occupying a smaller area, consumes about 28% of the available water followed by rainfed agriculture, which consumes about 20%. Plausible figures for the effect of the Karkheh Dam suggest that it will reduce flows downstream of the Dam and the inflow into the Hawr Al Azim marshes.Item Water-use accounts in CPWF basins: Simple water-use accounting of the Volta Basin(Working Paper, 2010) Kirby, M.; Condappa, D. de; Mainuddin, M.; Eastham, Judy; Thomas, M.This paper apples the principle of west –use accounts, developed in the first of the series, to the Volta River in West Africa. The Volta Basin covers six countries, with 85% of its area in Ghana and Burkina Faso. Runoff in all three tributaries increases from 2-7% in the drier north to 12-26 % in the higher – rainfall south. Grassland is the dominant land use throughout Basin ranging from 76% of the Delta catchment in the south to 98% of the Arly catchment with corresponding water use of 55% and 92% of water used in each. Increasing irrigation in the basin of all three tributaries to about one-third of the land identified by FAO as potentially irrigable gives lower flows and storage in the Dam.Item Water use accounts in CPWF basins: Simple water use accounting of the Limpopo Basin(Working Paper, 2010) Eastham, Judy; Kirby, M.; Mainuddin, M.; Thomas, M.Item Water use accounts in CPWF basins: Simple water use accounting of the Ganges Basin(Working Paper, 2010) Kirby, M.; Mainuddin, M.; Eastham, Judy; Thomas, M.Item Water-use accounts in CPWF basins: Simple water-use accounting of the Yellow River Basin(Working Paper, 2010) Mainuddin, M.; Eastham, Judy; Kirby, M.; Thomas, M.This paper applies the principles of water-use accounts, developed in the first of the series, to the Yellow River basin in China. The Yellow River rises in the Bayan Har Mountains in Qinghai Province in western China, and empties into the Bohai Sea. A unique feature of the river is the large amount of silt it carries. Net runoff is about 14% of total precipitation. Forest and woodland cover 9% of the basin and use about 15% of the precipitation. Grassland covers much of the upper part of the Basin, consuming about 42% of the precipitation. Irrigated agriculture covers just 6% of the Basin and uses about 11% of the water. The effect of increased irrigation efficiency shows that local increase of irrigation efficiency does not necessarily translate into changes at the whole basin level. The water transfer to the Yellow River from the Yangtze boost flows to the upper Yellow river and leads to an increase in the flows throughout the river. Keywords: Water use accounts, Yellow basin, top-down modeling, basin water useItem Water-use accounts in CPWF basins: Simple water-use accounting of the São Francisco Basin(Working Paper, 2010) Eastham, Judy; Kirby, M.; Mainuddin, M.This paper applies the principles of water-use accounts, developed in the first of the series, to the São Francisco basin in South America. The São Francisco Basin lies wholly within Brazil. There are several major dams and wetlands in the Basin. Net runoff is about 16% of total precipitation. Grassland is the most extensive land use, covering 59% of the Basin and uses 48% of the water. Rainfed agriculture covers 23% of the basin, but uses 14% of the water in the Basin. Forest and woodland cover 16% of the basin and use about 21% of the precipitation. Grassland covers much of the upper part of the Basin, consuming about 21% of the precipitation. Irrigated agriculture covers just about 2% of the Basin and uses about 2% of the water. Climate change, using an assumed change in increase in rainfall and evapotranspiration distribution, reduces flow at Juazeiro and storage in the Sobradinho reservoir. The transfer of water from the São Francisco Basin to the northeast of Brazil reduces annual average flow by 6% only. However, the combined impact of the planned diversions and drying due to climate change would be greater again. Keywords: Water use accounts, São Francisco basin, top-down modeling, basin water use.Item Water-use accounts in CPWF basins: Simple water-use accounting of the Niger Basin(Working Paper, 2010) Mainuddin, M.; Eastham, Judy; Kirby, M.This paper applies the principles of water-use accounts, developed in the first of the series, to the Niger River basin in West Africa. The Niger Basin covers 10 countries, and rises in the highlands of southern Guinea near the border with Sierra Leone just 240 km inland from the Atlantic Ocean, but there are substantial downstream tributaries from Cameroon and Nigeria. A unique feature is the inland delta which forms where its gradient suddenly decreases. Net runoff is about 12% of total precipitation. Grassland is the most extensive vegetation, covering 50% of the Basin, consuming about 39% of the precipitation. Rainfed agriculture covers 26% of the basin and use about 27% of the precipitation. Irrigated agriculture covers less than 1% of the Basin and uses also less than 1% of the water. Climate change, using an assumed change in rainfall distribution, shows that climate change may have a large impact on water availability in the lower Basin, and hence on the River’s wetlands.Item Water-use accounts in CPWF basins: Simple water-use accounting of the Indus Basin(Working Paper, 2010) Eastham, Judy; Kirby, M.; Mainuddin, M.; Thomas, M.This paper applies the principles of water-use accounts, developed in the first of the series, to the Indus River basin in South Asia. The Indus Basin covers 3 countries, rises in the Tibetan plateau in the vicinity of Lake Mansarovar in China. Irrigated agriculture in the Basin is extensive with the construction of dams, barrages, and link canals to distribute water, with modern engineering to support irrigation starting as early as the mid 1800s. Net runoff is about 10% of total precipitation. Irrigated agriculture covers 20% of the basin and use about 31% of the precipitation. Grassland is the most extensive vegetation, covering 45% of the Basin, consuming about 36% of the precipitation. Rainfed agriculture covers 14% of the Basin and uses about 15% of the water. Changing irrigation efficiency from the currently assumed 40% to 60% and increasing the irrigated area by 10% has relatively little impact on water availability overall, since the water thus made available can be consumed downstream. Keywords: Water use accounts, Indus basin, top-down modeling, basin water use.Item Water-use accounts in CPWF basins: Models and Concepts(Working Paper, 2010) Kirby, M.; Mainuddin, M.; Eastham, JudyThis paper applies the principles of water-use accounts, developed in the first of the series, to the Nile River basin in Northeast Africa. The Nile and its tributaries flow though nine countries. The White Nile flows though Uganda, Sudan, and Egypt. The Blue Nile starts in Ethiopia. Zaire, Kenya, Tanzanian, Rwanda, and Burundi all have tributaries, which flow into the Nile or into Lake Victoria. Unique features are Lake Victoria and the Sudd wetland where White Nile loses about half of its flow by evaporation, and the Aswan Dam which controls flow in the lower part of the Basin and also is where 15-20% of the flow is lost to seepage and further evaporation. Net runoff is minimal in many catchments of the Nile Basin, comprising 6% or less of the water available in 16 catchments of the Basin. In the remaining catchments, net runoff ranges from 9% (Panyango) to 34% (Gambella) of the available water. Water use by grassland is important in all catchments where it comprises 13 to 76% of the water available, except in the Lower Basin, where it comprises only 7% or less of the available water. In upstream catchments, woodlands and forests are the major components of land-use, while in the Lower Basin catchments barren and sparsely vegetated land is the main land-use class. Rainfed agriculture is the most important water use by volume in only four catchments, Kessie, Paraa, Panyango, and the Sennar Dam where it comprises 24%, 27%, 30%, and 38% of the available water. Nevertheless, it is a relatively important use of water in many of the catchments, using 10% or more of the available water in 14 catchments of the Basin. Irrigated agriculture is the least use of water by volume, using 4% or less of the available water in all catchments except the d/s of Jebel Aulia, the Sennar Dam, Thamaniyat, Hudeiba, Atbara, Naga Hammadi, El Ekhsase, and Estuary catchments. It is, however, the most important water use in the Estuary catchment, using 90% of the available water. The effect of climate change on rainfall in the Nile Basin is very uncertain, but temperature is expected increase by about 2°C by mid-century. To show the possible effects, we increased potential evapotranspiration by 5%, and left rainfall unchanged. The flow at Aswan Dam declines by about 6%, and irrigated crop water use in the El- Ekhsase region increases by about 2%.Item Water-use accounts in CPWF basins: Simple water-use accounting of the Nile Basin(Working Paper, 2010) Kirby, M.; Eastham, Judy; Mainuddin, M.This paper applies the principles of water-use accounts, developed in the first of the series, to the Nile River basin in Northeast Africa. The Nile and its tributaries flow though nine countries. The White Nile flows though Uganda, Sudan, and Egypt. The Blue Nile starts in Ethiopia. Zaire, Kenya, Tanzanian, Rwanda, and Burundi all have tributaries, which flow into the Nile or into Lake Victoria. Unique features are Lake Victoria and the Sudd wetland where White Nile loses about half of its flow by evaporation, and the Aswan Dam which controls flow in the lower part of the Basin and also is where 15-20% of the flow is lost to seepage and further evaporation. Net runoff is minimal in many catchments of the Nile Basin, comprising 6% or less of the water available in 16 catchments of the Basin. In the remaining catchments, net runoff ranges from 9% (Panyango) to 34% (Gambella) of the available water. Water use by grassland is important in all catchments where it comprises 13 to 76% of the water available, except in the Lower Basin, where it comprises only 7% or less of the available water. In upstream catchments, woodlands and forests are the major components of land-use, while in the Lower Basin catchments barren and sparsely vegetated land is the main land-use class. Rainfed agriculture is the most important water use by volume in only four catchments, Kessie, Paraa, Panyango, and the Sennar Dam where it comprises 24%, 27%, 30%, and 38% of the available water. Nevertheless, it is a relatively important use of water in many of the catchments, using 10% or more of the available water in 14 catchments of the Basin. Irrigated agriculture is the least use of water by volume, using 4% or less of the available water in all catchments except the d/s of Jebel Aulia, the Sennar Dam, Thamaniyat, Hudeiba, Atbara, Naga Hammadi, El Ekhsase, and Estuary catchments. It is, however, the most important water use in the Estuary catchment, using 90% of the available water. The effect of climate change on rainfall in the Nile Basin is very uncertain, but temperature is expected increase by about 2°C by mid-century. To show the possible effects, we increased potential evapotranspiration by 5%, and left rainfall unchanged. The flow at Aswan Dam declines by about 6%, and irrigated crop water use in the El- Ekhsase region increases by about 2%. Keywords: Water use accounts, Nile basin, top-down modelling, basin water useItem Water-use accounts in CPWF basins: Simple water-use accounting of the Mekong Basin(Working Paper, 2010) Kirby, M.; Mainuddin, M.; Eastham, JudyThis paper applies the principles of water-use accounts, developed in the first of the series, to the Mekong River basin in Southeast Asia. The Mekong Basin covers six countries, the River rises in China, but there are substantial downstream tributaries from Thailand, Laos, Cambodia, and Vietnam, and from a small area in Myanmar. A unique feature is the reverse flow from the Mekong to the Tonle Sap via the Tonle Sap River at the height of the wet season flow and its ebb as the river levels fall. Net runoff is about 37% of total precipitation. Forest and woodland cover 43% of the basin and use about 33% of the precipitation. Grassland covers much of the upper part of the Basin, consuming about 6% of the precipitation. Irrigated agriculture covers just 6% of the Basin and uses about 6% of the water (excluding runoff). Climate change, using an assumed change in rainfall distribution, shows that with the expected shorter and more intense rainy season, and longer and more intense dry season, both floods and seasonal water shortages may be exacerbated. Keywords: Water use accounts, Mekong basin, top-down modeling, basin water use