Your search found 11 records
1 Sharma, P. N.; Helweg, O. J.. 1981. An evaluation of traditional small reservoir irrigation systems in semi-arid India. Journal of Agricultural Engineering, ISAE, 20(3&4):101-110.
Arid zones ; Irrigation ; Reservoirs ; Water use efficiency ; Water balance ; Evaluation ; Small scale systems / India
(Location: IWMI-HQ Call no: P 1349 Record No: H03975)
2 Helweg, O. J.. 1989. Evaluating the traveling trickler center pivot. ICID Bulletin, 38(1):13-20.
(Location: IWMI-HQ Call no: PER Record No: H05756)
There have been a number of proposals to improve the centre pivot irrigation system. Most of them sought to decrease their energy requirements by lowering system pressure. Recently, however, there has been an interest in improving irrigation efficiency. In arid regions such as Saudi Arabia in which center pivot system experience greater amounts of evaporation than other climates, improving irrigation efficiency is extremely important. The two most recent suggested modifications employ low pressure drop pipes and dragging perforated pipes along rows to decrease the instantaneous applications rates: however, these and all previous low pressure or drop systems are proposed only for row crops. The travelling trickler system that is specifically designed for grain crops shows promise of being more efficient than any centre pivot modifications yet proposed. The prototype system consists of a number of micro tubes (emitters) spaced twice the grain row distance that are hydraulically designed to apply a uniform amount of water directly to the soil. The travelling trickler system applied almost 40% less water than a standard center pivot, operating at one-fourth of the pressure.
3 Hussain, G.; Sadiq, M.; Nabulsi, Y. A.; Helweg, O. J.. 1994. Effect of saline water on establishment of windbreak trees. Agricultural Water Management, 25(1):35-43.
(Location: IWMI-HQ Call no: PER Record No: H014064)
A pot experiment was conducted to determine the effect of saline water on the establishment of windbreak trees and soil properties. Survival period of trees decreased significantly with increase in soil salinity resulted from irrigation water salinity. The survival period of Prosopis juliflora was significantly more than Casuarina equisetifolia and Eucalyptus camaldulensis. The decrease in total biomass yield was significant with increase in soil salinity. Soil salinity and sodicity increased significantly with an increase in irrigation water salinity and sodicity. Prosopis juliflora tolerated soil salinity (EC e) up to 38.3 dS.m-1 with irrigation water salinity of 13.5 dS.m-1, Casuarina equisetifolia up to 27.6 dS.m-1 with irrigation water salinity of 6.6 dS.m-1 and Eucalyptus camaldulensis up to 15.2 dS.m-1 with irrigation water salinity of 2.12 dS.m-1 for proper establishment provided 15% excess water is applied as leaching requirement to control soil salinity. The experiment proved the sequence in salt tolerance for different trees as prosopis > casuarina > eucalyptus. The results suggested that prosopis juliflora should be cultivated as windbreak trees in landscape and sand stabilization projects.
4 Pezeshk, S.; Helweg, O. J.; Oliver, K. E. 1994. Optimal operation of groundwater supply distribution systems. Journal of Water Resources Planning and Management, 120(5):573-586.
Groundwater management ; Water supply ; Water distribution ; Optimization methods ; Pumping ; Simulation models / USA / Tennessee / Memphis
(Location: IWMI-HQ Call no: PER Record No: H015100)
5 Latifi, H.; Prasad, S. N.; Helweg, O. J.. 1994. Air entrapment and water infiltration in two-layered soil column. Journal of Irrigation and Drainage Engineering, 120(5):871-891.
(Location: IWMI-HQ Call no: PER Record No: H015370)
6 Hussain, G.; Helweg, O. J.. 1994. Effect of saline irrigation water on tree growth. Journal of Irrigation and Drainage Engineering, 120(5):970-978.
(Location: IWMI-HQ Call no: PER Record No: H015377)
7 Sharma, P. N.; Helweg, O. J.. 1982. Optimal design of small reservoir systems. Proceedings of the American Society of Civil Engineers, 108(IR4):250-264.
(Location: IWMI-HQ Call no: P 4034 Record No: H05087)
8 Helweg, O. J.; Ormsbee, L. E. 1994. Lesson learned from implementing M & I optimal water delivery. In Fontane, D. G.; Tuvel, H. N. (Eds.), Water policy and management: Solving the problems: Proceedings of the 21st annual conference, ASCE, Denver, Colorado, May 23-26, 1994. New York, NY, USA: ASCE. pp.730-733.
Water delivery ; Optimization ; Water distribution ; Operations ; Models ; Monitoring ; Wells ; Pumping / USA
(Location: IWMI-HQ Call no: 333.91 G000 FON Record No: H019848)
9 Sisodia, S.; Helweg, O. J.. 1998. Modeling the heat sense flowmeter. Journal of Irrigation and Drainage Engineering, 124(3):148-151.
Flow measurement ; Velocity ; Measuring instruments ; Mathematical models ; Simulation ; Aquifers ; Groundwater
(Location: IWMI-HQ Call no: PER Record No: H022449)
10 Tibor, G. J.; Grigg, N. S.; Helweg, O. J.; Plusquellec, H.; Burt, C. M. 2000. Problems of irrigation in developing countries: Discussions. Journal of Irrigation and Drainage Engineering, 126(3):195-202.
(Location: IWMI-HQ Call no: PER Record No: H026242)
11 Helweg, O. J.. 2000. Water for a growing population: Water supply and groundwater issues in developing countries. Water International, 25(1):33-39.
Water supply ; Population growth ; Groundwater development ; Wells ; Aquifers ; Water quality ; Infrastructure ; Developing countries
(Location: IWMI-HQ Call no: PER Record No: H026265)
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