Browsing by Author "Turral, Hugh"

Now showing 1 - 12 of 12

Closing of the Krishna Basin: Irrigation, Streamflow Depletion and Macroscale Hydrology
(2007) Biggs, Trent W.; Gaur, Anju; Scott, Christopher; Thenkabail, Prasad; Gangadhara Rao, Parthasaradhi; Gumma, Murali Krishna; Acharya, Sreedhar; Turral, Hugh
"Discharge from the Krishna River into the ocean decreased by 75 percent from 1960-2005, and was zero during a recent multi-year drought. This paper describes the physical geography and hydrology of the Krishna Basin, including runoff production and a basic water account based on hydronomic zones. More than 50 percent of the basin's irrigated area is groundwater irrigation, which is not currently included in inter-state allocation rules. Future water allocation will require inclusion of the interactions among all irrigated areas, including those irrigated by groundwater and surface water."
Demand Management in a Basin Perspective: Is the Potential for Water Saving Overestimated?
(2005) Molle, François; Turral, Hugh
"Water Demand management has received much emphasis from development agencies in the last decade. The concept stemmed from a growing awareness of the externalities of large scale water resources development and of an assumed state of wastage in the use of water by many sectors, notably agriculture. The paper examines critically the scope for saving water in water short basins. It argues that because of the closing/closed nature of such basins, the gains that can be achieved through demand management have been much overstimated. It shows that demand management interventions result in some users being able to increase their water use to the detriment management interventions result in some users being able to increase their water use to the detriment of downstream users and that most interventions result in spatial shifts of water use rather than savings. Water pricing is often proposed as a way to curb water use but its introduction in irrigated agriculture is shown to be problematic. The economic argument for re-allocation to higher value uses is distinct from the discussion of water savings in the paper and is not considered in any detail. The paper also suggests that supply management remains indeed the most effective way to reduce water use, and that in many cases supply augmentation cannot be avoided."
From Mesopotamia to the Third Millennium: The Historical Trajectory of Water Development and Use in the Karkheh River Basin, Iran
(2009) Marjanizadeh, Sara; Qureshi, Asad Sarwar; Turral, Hugh; Talebzadeh, Parviz
"The Karkheh River Basin is the third largest basin in Iran after Karoon and Dez, and occupies a strategic position on the western boundary of the country. The basin has seen remarkable ancient feats of engineering, and has a long history of wheat and barley production, complemented by horticulture. With the growth of the modern nation-state of Iran, water development has progressed steadily in tandem with rising populations and urbanization. The report aims to understand the historical setting and present situation of water development and allocation, in relation to rural development and agrarian policy. It provides the contextual backdrop for further research on the management of water to improve livelihoods in the basin through integrated and sustainable management of land and water resources. It provides further information on the changes in surface flows out of the component subbasins and looks at the development, use and consequences of groundwater abstraction."
Fusion Technique to Extract Detail Information from Moderate Resolution Data for Global Scale Image Map Production
(2003) Canisius, Francis X. J.; Turral, Hugh
"The Global Irrigated Area mapping project at IWMI addresses the need to develop improved regional or global image products that incorporate spatial and temporal heterogeneity of agriculture. Fusion of freely available high temporal resolution MODIS composite image and high spatial resolution GeoCover Landsat TM mosaic is an appropriate approach to monitor temporal and spatial variability in agriculture at global scale. Methodologies were developed using the techniques of IHS color transformation and Principal Component Analysis to produce global image fusion products. In these processes, the spectral characteristics of the original MODIS multi-spectral image are maintained. In effect one can clearly identify the textural and structural features of land cover as well as the vegetation cover at the period of MODIS data acquisition. Moreover it improves classification accuracy and spatial disaggregation."
India's Water Future to 2025-2050: Business-as-Usual Scenario and Deviations
(2007) Amarasinghe, Upali A.; Shah, Tushaar; Turral, Hugh; Anand, B. K.
"With a rapidly expanding economy many changes are taking place in India today. The business-as-usual (BAU) scenario, which assumes the continuation of current trends of key water demand drivers, will meet the future food demand. However, it leads to a severe regional water crisis by 2050, where many river basins will reach closure, will be physically water-scarce and will have regions with severely overexploited groundwater resources. While the alternative scenarios of water demand show both optimistic and pessimistic water futures, the scenario with additional productivity growth is the most optimistic, with significant scope for reducing future water demand."
An Irrigated Area Map of the World (1999) Derived from Remote Sensing
(2006) Thenkabail, Prasad; Biradar, Chandrashekhar M.; Turral, Hugh; Noojipady, Praveen; Li, Y. J.; Vithanage, J.; Dheeravath, Venkateswarlu; Velpuri, Manohar; Schull, M.; Cai, X. L.; Dutta, R.
"It is necessary to accurately quantify the area and intensity of irrigation in the world in order to properly understand its contribution to food production and security, and to estimate its water use, as competition for water increases with rising urban and industrial needs and the recognition of environmental water requirements. Satellite remote sensing offers a relatively cheap, repeatable and accurate technology to estimate and monitor irrigated areas. This research report presents the results of a global analysis of multi-temporal time series at nominal 10 kilometer pixel resolution. Statistics of irrigation at country level are derived from these maps for different seasons and for the entire year (annualized) for the nominal year of 1999. Three methods of area abstraction are used and compared, and three methods of accuracy assessment are applied. The annualized irrigated areas of the world at the end of the last millennium were about 480 Mha of which there were 263 Mha for season 1, 176 Mha for season 2, and 41 Mha for continuous cropping. Of this, Asia alone accounts for 78 percent (375 Mha) with 59 percent from China and India. The country statistics are compared with FAO country-level statistics (see Annex I). The IWMI GIAM 10 km V2.0 map were tested based on 3 sources of independent data resulting in accuracies between 84 and 91 percent with errors of omission not exceeding 16 percent and errors of commission less than 21 percent. The total area available for irrigation (TAAI; the nearest equivalent to FAO's equipped area)was 412 Mha. The global irrigated area mapping (GIAM) products (e.g., maps, statistics, web maps) are made available through a dedicated web portal (http://www.iwmigiam.org). The detailed methodology is also made available through the web portal. The focus of this research report is on the results of the GIAM mapping effort."
Recent Trends in Irrigation Management Changing Directions for the Public Sector
(1995) Turral, Hugh
"This paper discusses responses to the under-performance of irrigated agriculture, highlighting the changing relationships between the state and users in the operation and maintenance of publicly-funded irrigation schemes. It begins with a summary of the reasons for and responses to under-performance in the sector and then outlines the institutional and economic background that favours local cooperation and coordination in irrigation management. The focus of the paper is on management transfer and privatisation of irrigation, with reference to the broader problem of inter-sectoral water allocation and the accompanying transformation of the role of state agencies from implementation to service provision and thence to enablement and regulation."
A Review of Management Strategies for Salt-prone Land and Water Resources in Iran
(2007) Qureshi, Asad Sarwar; Qadir, Manzoor; Heydari, Nader; Turral, Hugh; Javadi, Arzhang
"Approximately half of the irrigated area of Iran falls under different types of salt-affected soils and average yield losses may be as high as 50 percent. Slightly and moderately salt-affected soils are mostly found on the piedmonts at the foot of the Elburz (Alborz) Mountains in the northern part of the country. The soils having severe to extreme salinity are predominantly located in the Central Plateau, the Khuzestan and Southern Coastal Plains and the Caspian Coastal Plain. The process of salinization of the surface water resources is mainly due to natural conditions, and to a lesser extent, to the discharge of drainage water into the river systems. Estimates show that about 6.7 km3 of brackish water flow annually through 12 major rivers. There is no straightforward solution to the complex problems of salt-induced soil and water resources degradation in Iran. The approaches addressing the management of these resources need to be multidimensional and must take into account biophysical and environmental conditions of the target areas as well as livelihood aspects of the associated communities."
Shifting Waterscapes: Explaining Basin Closure in the Lower Krishna Basin, South India
(2007) Venot, Jean-Philippe; Samad, Madar; Turral, Hugh; Molle, François
"Progressive agricultural and water development in the Krishna Basin in South India has led to a rising overcommitment of water resources and signs of basin closure are apparent during dry periods. As human consumptive uses are approaching the limits of water availability, this report focuses on the Lower Krishna Basin that bears the brunt of any intervention upstream. Capturing the process of basin closure requires an understanding of the political dimension of access to water and the scope for change. As basin closure intensifies the interconnectedness of ecosystems and water users, adjustments and management decisions result in spatial re-appropriation of water and basin-wide strategies for water management and development that start with the definition and the implementation of water allocation mechanisms are increasingly needed."
Strategies for the Management of Conjunctive use of Surface Water and Groundwater Resources in Semi-arid Areas
(2004) Qureshi, Asad Sarwar; Turral, Hugh; Masih, Ilyas
"This report presents the results of a modeling study carried out to evaluate the long-term effects of a different quality of irrigation water on root zone salinity. The simulations were performed for the Rechna Doab (subbasin of the Indus Basin), Punjab, Pakistan by using 15 years of actual rainfall and climatic data. Rechna Doab covers approximately 2.8 million hectares of cultivated land. Groundwater quality in Rechna Doab varies from north to south. In the upper part of the doab, groundwater is relatively fresh (EC = 1.0 dSm-1), in the middle, there are several pockets where groundwater quality is marginal (EC = 1.5 - 2.7 dSm-1) and in the lower part of the doab groundwater is highly saline (EC > 2.7 dSm-1). In all these areas, groundwater is mixed with canal water in different ratios without knowing the consequences of any quality hazard. For model simulations, groundwater of these three qualities (i.e., 1.0 dSm-1, 1.5 dSm-1, and 3.0 dSm-1) was mixed with canal water in four different ratios i.e., 0 percent, 25 percent, 50 percent and 75 percent. In total 12 different scenarios were generated. The resultant water quality of each scenario was used as input to the model to study the long-term effects of this water quality on crop production and soil salinization. "The simulation results indicate that in fresh groundwater areas, farmers present irrigation practices i.e., mixing groundwater and canal water with a 1:1, which ratio provides sufficient leaching to push salts below the root zone, thereby minimizing the risk of reduction in crop production. The direct use of fresh groundwater for irrigation will accumulate salts at shallow depths in the root zone, therefore, the risk of an upward movement of salts due to capillary action during a dry year will be high. Under these conditions, occasional leaching with canal water will be necessary to maintain favorable salt balance in the root zone."
Sustaining Crop Water Productivity in Rice-Wheat Systems of South Asia: A Case Study from the Punjab, Pakistan
(2007) Jehangir, Waqar A.; Masih, Ilyas; Ahmed, Shehzad; Gill, Mustaq Ahmad; Ahmad, Maqsood; Mann, Riaz Ahmad; Chaudhary, Muhammad Rafiq; Qureshi, Asad Sarwar; Turral, Hugh
"This working paper presents the results of the Pakistan Component of the Rice-Wheat Consortium Project on 'Sustaining the rice-wheat production systems of Asia'. Rice and wheat crops are main sources of human food and substantially contribute to feeding livestock. The advent of the green revolution in the 1960s resulted in a tremendous increase in the production of these two cereal crops and the rice-wheat cropping system emerged as a very important source of food supply in South Asia."
Water Saving Technologies: Myths and Realities Revealed in Pakistan's Rice-Wheat Systems
(2007) Ahmad, Mobin-ud-Din; Turral, Hugh; Masih, Ilyas; Giordano, Mark; Masood, Zubair
"This study uses both farmer surveys and physical measurements to understand the impact RCTs have had on water use and water savings in the irrigated Rice-Wheat Zone of Pakistan's Punjab province. The findings show that field scale water savings achieved from RCTs is not necessarily equivalent to water savings at broader scales and may even result in an increase in overall water depletion."