Your search found 11 records
1 Khanjani, M. J. 1980. Methodology for optimization of an irrigation system with storage reservoirs. xiii, 313p.
Irrigation systems ; Reservoirs ; Optimization ; Cost benefit analysis ; Probability analysis ; Economic analysis ; Computer software ; Water requirements ; Mathematical models ; Water distribution ; Evapotranspiration ; Rehabilitation
(Location: IWMI-HQ Call no: 631.7.1 G000 KHA Record No: H0886)
A procedure was developed to specify optimal plans for an irrigation system with temporary internal storage. The procedure was used to develop plans for 1865 ha using farm service reservoirs. Daily potential and actual evapotranspiration for 25 years were computed. Probability distributions of potential and actual evapotranspiration for 1-30 days duration were estimated. A log-normal probability distribution was found to best fit the data, and probability equations for different durations were computed. These distributions were used to determine possible irrigation intervals for different crops growing in different soil types. Costs of different types of irrigation subsystem components such as canal sections, farm service reservoirs, pumps, and sprinkler and gravity application subsystems were computed. A marginal cost and benefit analysis was used to select the best irrigation intervals for all soil-crop combinations. The time of occurrence of maximum evapotranspiration for each crop was analyzed and found to follow a log-normal distribution. Water-use information was used to compute the volume of interval storage needed within the system. Fifteen farm service reservoirs were located at 15 specified sites by considering physical conditions and other restrictions. Costs and design capacities of farm service reservoirs and canal sections of the system were computed. By utilizing a mixed integer programming model, the locations of farm service reservoirs were optimized; and seven of the original 15 farm service reservoir sites were selected. A linear programming model was then used to compute the optimum capacity of each farm service reservoir, and parametric programming was used to examine the effects of varying water costs of system configuration. The cost and design capacity of the irrigation system with seven farm service reservoirs was computed.
2 Christensen, R. 1981. Entropy minimax sourcebook. Vol I: General description. Lincoln, MA, USA: Entropy Ltd. xx, 692 p.
Information theory ; Engineering ; Statistics ; Forecasting ; Hydrology ; Entropy ; Probability analysis
(Location: IWMI-HQ Call no: 001.539 G000 CHR Record No: H01949)
3 Kerlinger, F. N. 1973. Foundations of behavioral research. New York, NY, USA: Holt, Rinehart and Winston Inc.
(Location: IWMI-HQ Call no: 001.4 G000 KER Record No: H02541)
4 Yixing, B.; Yeou-Koung, T.; Hasfurther, V. R. 1987. Evaluation of uncertainty in flood magnitude estimator on annual expected damage costs of hydraulic structures. Water Resources Research, 23(11):2023-2029.
Flood control ; Costs ; Irrigation design ; Estimation ; Hydraulic structures ; Uncertainty ; Probability analysis ; Models
(Location: IWMI-HQ Call no: PER Record No: H02827)
(0.00 MB)
In the risk based design for hydraulic structures, the major task is the evaluation of the annual expected damage costs caused by floods. Due to the use of a limited amount of data in flood frequency analysis, the computed flood magnitude of a specified return period is subject to uncertainty. A methodology to integrate such uncertainty in the evaluation of annual expected flood damage is developed and illustrated through an example in culvert design. The effect of uncertainty in estimating flood magnitude using different hydrologic probability models with different sample sizes on the annual expected damage cost is examined. Results of the study show that the effect of the uncertainty in a flood magnitude estimate on annual expected damage is quite significant and is sensitive to the sample sizes and the probability distribution models used.
5 Trezos, T.; Yen, W. G. W. 1987. Use of stochastic dynamic programming for reservoir management. Water Resources Research, 23(6):983-996.
Reservoirs ; Stochastic process ; Water management ; Hydrology ; Energy ; Forecasting ; Probability analysis ; Case studies
(Location: IWMI-HQ Call no: PER Record No: H03167)
6 Sritharan, S. I.; Clyma, W.; Richardson, E. V. 1988. Sizing of terminal units in surface irrigation projects: I. Journal of Water Resources Planning and Management, 114(1):20-37.
Surface irrigation ; Equitable apportionment ; Terminal level irrigation ; Probability analysis ; Water distribution ; Mathematical models ; Farming ; Social aspects
(Location: IWMI-HQ Call no: PER Record No: H03679)
7 Blalock, H. M. 1960. Social statistics. 2nd ed. New York, NY, USA: McGraw-Hill. xiv, 583p. (McGraw-Hill series in sociology)
(Location: IWMI-HQ Call no: 519.5 G000 BLA Record No: H022397)
8 Podgorski, J. E.; Eqani, S. A. M. A. S.; Khanam, T.; Ullah, R.; Shen, H.; Berg, M. 2017. Extensive arsenic contamination in high-pH unconfined aquifers in the Indus Valley. Science Advances, 3(8):1-10. [doi: https://doi.org/10.1126/sciadv.1700935]
Arsenic ; Contamination ; Groundwater ; Aquifers ; pH ; Water quality ; Drinking water ; Public health ; Health hazards ; Soils ; Probability analysis ; Regression analysis ; Models ; Forecasting / Pakistan / Indus Valley
(Location: IWMI HQ Call no: e-copy only Record No: H048293)
http://advances.sciencemag.org/content/3/8/e1700935.full.pdf
https://vlibrary.iwmi.org/pdf/H048293.pdf
https://vlibrary.iwmi.org/pdf/H048293.pdf
(0.96 MB) (980 KB)
Arsenic-contaminated aquifers are currently estimated to affect ~150 million people around the world. However, the full extent of the problem remains elusive. This is also the case in Pakistan, where previous studies focused on isolated areas. Using a new data set of nearly 1200 groundwater quality samples throughout Pakistan, we have created state-of-the-art hazard and risk maps of arsenic-contaminated groundwater for thresholds of 10 and 50 mg/liter. Logistic regression analysis was used with 1000 iterations, where surface slope, geology, and soil parameters were major predictor variables. The hazard model indicates that much of the Indus Plain is likely to have elevated arsenic concentrations, although the rest of the country is mostly safe. Unlike other arsenic-contaminated areas of Asia, the arsenic release process in the arid Indus Plain appears to be dominated by elevated-pH dissolution, resulting from alkaline topsoil and extensive irrigation of unconfined aquifers, although pockets of reductive dissolution are also present. We estimate that approximately 50 million to 60 million people use groundwater within the area at risk, with hot spots around Lahore and Hyderabad. This number is alarmingly high and demonstrates the urgent need for verification and testing of all drinking water wells in the Indus Plain, followed by appropriate mitigation measures.
9 Bocchiola, D.; Pelosi, M. G.; Soncini, A. 2017. Effects of hydrological changes on cooperation in transnational catchments: the case of the Syr Darya. Water International, 42(7):852-873. [doi: https://doi.org/10.1080/02508060.2017.1376568]
International waters ; Catchment areas ; International cooperation ; Hydrological regime ; Water management ; Climate change ; Water use ; Conflict ; Flow discharge ; Cost benefit analysis ; Profitability ; Statistical methods ; Game theory ; Models ; Probability analysis ; Case studies / Central Asia / Uzbekistan / Kazakhstan / Kyrgyzstan / Syr Darya Catchment / Toktogul Dam
(Location: IWMI HQ Call no: e-copy only Record No: H048381)
(2.31 MB)
Water allocation along the Syr Darya River may be affected by climate change. Here we statistically model cooperation strategies, country profits, and sensitivity of cooperation, showing that the hydrological regime affects transboundary cooperation. Climate change in the twenty-first century may reduce glacial cover, and reducing stream flows, decreasing chances of cooperation and potentially raising conflicts. Comparison with other transboundary catchments in Central Asia indicates moderate-to-high risk of conflicts for the Syr Darya. A template is provided for assessment of the stability of cooperation in the Syr Darya basin, and in catchments similarly dependent on water availability.
10 Kheradmand, S.; Seidou, O.; Konte, D.; Batoure, M. B. B. 2018. Evaluation of adaptation options to flood risk in a probabilistic framework. Journal of Hydrology: Regional Studies, 19:1-16. [doi: https://doi.org/10.1016/j.ejrh.2018.07.001]
Flooding ; Risk assessment ; Adaptation ; Evaluation ; Floodplains ; Weather hazards ; Mapping ; Probability analysis ; Hydrology ; Models / West Africa / Niger / Niamey / Niger River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H048913)
https://www.sciencedirect.com/science/article/pii/S2214581818300417/pdfft?md5=882a660199d75c84e350d4a6d94ec2aa&pid=1-s2.0-S2214581818300417-main.pdf
https://vlibrary.iwmi.org/pdf/H048913.pdf
https://vlibrary.iwmi.org/pdf/H048913.pdf
(5.66 MB) (5.66 MB)
Study region: City of Niamey, Niger, West Africa.
Study focus: This paper aims to explore the possibility of implementing a probabilistic framework for flood risk estimation for the city of Niamey, Niger. A probabilistic set of flood maps were generated by forcing a HEC-RAS model with a stochastically generated ensemble of flood peaks representing the river regime at Niamey. Loss curves were derived from expert judgment, and various adaptation options to flood risk were examined by considering two main variables: a) buildings’ material; b) dike height (ranged from 180.5 m to 184 m, at a 0.5 m interval) within a scenario-based framework. Floods with return periods of 2- to 1000-yr were considered in estimating total loss, and benefits and costs of different adaptation options were compared.
New hydrological insights for the region: It was found that increasing the height of the dikes would lead to smaller economic losses, while rebuilding with better materials would increase the average annual economic losses, but might decrease the risk of human casualties. Individual and combined impact of decision variables on flood risk were estimated for the city of Niamey. Quantitative tools were developed to help decision-makers and regulators choose the best preventive measures to mitigate flood risk.
Study focus: This paper aims to explore the possibility of implementing a probabilistic framework for flood risk estimation for the city of Niamey, Niger. A probabilistic set of flood maps were generated by forcing a HEC-RAS model with a stochastically generated ensemble of flood peaks representing the river regime at Niamey. Loss curves were derived from expert judgment, and various adaptation options to flood risk were examined by considering two main variables: a) buildings’ material; b) dike height (ranged from 180.5 m to 184 m, at a 0.5 m interval) within a scenario-based framework. Floods with return periods of 2- to 1000-yr were considered in estimating total loss, and benefits and costs of different adaptation options were compared.
New hydrological insights for the region: It was found that increasing the height of the dikes would lead to smaller economic losses, while rebuilding with better materials would increase the average annual economic losses, but might decrease the risk of human casualties. Individual and combined impact of decision variables on flood risk were estimated for the city of Niamey. Quantitative tools were developed to help decision-makers and regulators choose the best preventive measures to mitigate flood risk.
11 Feyisa, A. D.; Maertens, M.; de Mey, Y. 2023. Relating risk preferences and risk perceptions over different agricultural risk domains: insights from Ethiopia. World Development, 162:106137. (Online first) [doi: https://doi.org/10.1016/j.worlddev.2022.106137]
Agriculture ; Risk management ; Developing countries ; Policies ; Households ; Livestock ; Econometrics ; Models ; Uncertainty ; Probability analysis / Ethiopia / Southern Nations, Nationalities, and Peoples' Region (SNNPR) / Arba Minch Zuriya / Bonke / Chencha / Mirab Abaya / Konso / Derashe
(Location: IWMI HQ Call no: e-copy only Record No: H051569)
https://www.sciencedirect.com/science/article/pii/S0305750X22003278/pdfft?md5=b0df00ecee75822940aee58d3b682ac6&pid=1-s2.0-S0305750X22003278-main.pdf
https://vlibrary.iwmi.org/pdf/H051569.pdf
https://vlibrary.iwmi.org/pdf/H051569.pdf
(0.81 MB) (824 KB)
Households in developing countries are exposed to various shocks and risks, which leaves them vulnerable as they typically have limited resources to cope with them. Even though a large body of development literature has focused on the role of risk in rural livelihoods, the focus is often on single sources of risk and taking a unidimensional view on risk preference. This paper explores the diversity in risk perception and risk preferences of Ethiopian households by combining incentivized field experiments with detailed primary household survey data. We disentangle the relationship between risk perception and risk preferences using an innovative combination of time framing and instrumental variable estimation approaches. We find that our respondents are exposed to multiple past shocks and perceive multiple sources of future threats across different agricultural risk domains. Our respondents can be characterized as relatively risk-averse and loss-averse, and they also overweight unlikely extreme outcomes. We find a statistically significant association between the prospect theory risk preferences parameters—risk aversion, loss aversion, and probability weighting—and overall risk perception, domain-specific risk perceptions (except for the personal domain) and the impact dimension of future risk. Our findings make an important contribution to our understanding of farm households’ risk behavior, and can guide prioritizing development efforts to stimulate better informed and well-targeted risk management policy interventions.
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