Your search found 82 records
1 Ley, T. W.; El-Kady, M.; Litwiller, K. E.; Hanson, E.; Braunworth, W. S.; El-Falaky, A.; Wafik, E. 1984. The influence of farm irrigation system design and precision land leveling on irrigation efficiency and irrigation water management. Cairo, Egypt: Egypt Water Use and Management Project. xii, 97p. (EWUP technical report no.41)
Farming ; Irrigation design ; Gravity flow ; Flood irrigation ; Water management ; Field tests ; Water use efficiency / Egypt
(Location: IWMI-HQ Call no: 631.7.1 G232 LEY Record No: H0161)
The results of EWUP studies at each of three locations in Egypt: El-Mansuriya, Kafr El-Shiek and El-Minya, to characterize the conventional farm irrigation systems used by farmers in each area are summarized. The method used is surface gravity flooding of small, flat basins or small basins with short furrows. Numerous irrigation field trials on farms at the three EWUP study areas have been conducted. The practices tested included precision land levelling to dead level; level border strip or level long furrow irrigation system design; and teaching and advising farmers concerning improved on-farm water management practices in the use of the improved systems. Results were found to be highly successful when the spatial and temporal variations in farm irrigation system design factors were properly accounted for. A significant factor is the need to continue working with the farmer after system construction, teaching and advising him of improved management practices with the new systems. EWUP experience has shown that when farmers are well advised in using the new systems improved results are significant.
2 Drum, D. 1988. Infrared telemetry: A promising new management tool. Irrigation Journal, 38(6):18-19.
(Location: IWMI-HQ Call no: PER Record No: H05277)
3 Miller, E.; Tillson, T. J. 1989. Small scale irrigation in Sri Lanka: Field trials of a low head drip system. In Rydzewski, J. R.; Ward, C. F. (Eds.), Irrigation theory and practice. Proceedings of the International Conference, University of Southampton, 12-15 September. London: Pentech Press. pp.616-629.
Small scale systems ; Drip irrigation ; Field tests / Sri Lanka / Korakehawewa / Anuradhapura / Maha Illuppallama
(Location: IWMI-HQ Call no: 631.7 G000 RYD Record No: H07547)
4 Ortiz, R.; Ruano, S.; Olivet, H. J. F.; Meneses, A. 1991. A new model for technology transfer in Guatemala: Closing the gap between research and extension. The Hague, Netherlands: ISNAR. xiii, 29p. (OFCOR-discussion paper no.2)
(Location: IWMI-HQ Call no: 630.72 G356 ORT Record No: H08037)
5 Osment, J.; Reeve, D. E.; Maiz, N. B.; Moussa, M. 1991. A PC-based water quality prediction tool for Tunis North Lake. In Woolridge, R. (Ed.) Techniques for environmentally sound water resources development: Papers presented to the African Regional Symposium held in Alexandria, Egypt, 17-19 February 1991. London, UK: Pentech Press. pp.229-239.
(Location: IWMI-HQ Call no: 333.91 G000 WOO Record No: H08256)
6 Giay, M. A.; Zelenka, R. F. 1985. Experiences with the new ISO-test method on pressure compensated HB-system emitters. In Drip/trickle irrigation in action: Proceedings of the Third International Drip/Trickle Irrigation Congress, Centre Plaza Holiday Inn, Fresno, California, USA, November 18-21, 1985. Vol.1. pp.318-324.
(Location: IWMI-HQ Call no: 631.7.1 G000 DRI Record No: H09623)
7 Gomez, K. A. 1972. Techniques for field experiments with rice: Layout/sampling/sources of error. Los Ba¤os, Laguna, Philippines: IRRI. 46p.
(Location: IWMI-HQ Call no: P 2590 Record No: H011399)
8 Mwendera, E. 1992. 1992 Field visit to Ophoven-kinrooi Irrigation Project. Siphon, No.13:16-23.
(Location: IWMI-HQ Call no: P 2603 Record No: H011863)
9 Troch, P. A.; Mancini, M.; Paniconi, C.; Wood, E. F. 1993. Evaluation of a distributed catchment scale water balance model. Water Resources Research, 29(6):1805-1817.
Water balance ; Simulation models ; Hydrology ; Water table ; Calibrations ; Field tests ; Soil moisture ; Runoff ; Seepage / USA / Pennsylvania
(Location: IWMI-HQ Call no: PER Record No: H013092)
The validity of some of the simplifying assumptions in a conceptual water balance model is investigated by comparing simulation results from the conceptual model with simulation results from a three-dimensional physically based numerical model and with field observations. We examine, in particular, assumptions and simplifications related to water table dynamics, vertical soil moisture and pressure head distribution, and subsurface flow contributions to stream discharge. The conceptual model relies on a topographic index to predict saturation excess runoff and on Philip's infiltration equation to predict infiltration excess runoff. The numerical model solves the three-dimensional Richards equation describing flow in variably saturated porus media, and handles seepage face boundaries, infiltration excess and saturation excess runoff production, and soil driven and atmosphere driven surface fluxes. The study catchments are located in the North Appalachian ridge and valley region of eastern Pennsylvania. Hydrologic data collected during the MACHYDRO 90 field experiment are used to calibrate the models and to evaluate simulation results. It is found that water table dynamics as predicted by the conceptual model are close to the observations in a shallow water well and therefore, that a linear relationship between a topographic index and the local water table depth is found to be a reasonable assumption for catchment scale modeling. However, the hydraulic equilibrium assumption is not valid for the upper 100 cm layer of the unsaturated zone and a conceptual model that incorporates a root zone is suggested. Furthermore, theoretical subsurface flow characteristics from the conceptual model are found to be different from field observations, numerical simulation results, and theoretical baseflow recession characteristics based on Boussinesq's groundwater equation.
10 Mailhol, J. C.; Gonzalez, J. M. 1993. Furrow irrigation model for real-time applications on cracking soils. Journal of Irrigation and Drainage Engineering, 119(5):768-783.
Furrow irrigation ; Soil properties ; Infiltration ; Models ; Calibrations ; Field tests ; Statistical analysis ; Water use efficiency / France
(Location: IWMI-HQ Call no: PER Record No: H013359)
Clay soils frequently develop large cracks after irrigation. Infiltration equations therefore need to be modified to take cracking soil properties into account when modeling and optimizing furrow irrigation. In this article, we propose an infiltration equation for cracked soils, based on two parameters. Other parameters of the global model are assumed to be known (furrow length, shape, slope, and estimated roughness). One parameter is linked to the type of soil and is calibrated separately for the entire irrigation process. The second parameter takes soils' cracks into account and is calibrated in real time during the advance phase (before the water front overruns the middle of the plot). This global furrow irrigation model for cracked soils is derived from a conceptual approach and can be used either to predict in real time, water-use efficiency during irrigation (infiltrated volume, runoff water losses, uniformity) or to optimize irrigation parameters (head flow, irrigation duration). The model was tested and validated on three irrigation applications on 60 furrows in a corn field in Tarascon in southeastern France. This conceptual model can be easily adapted to the statistical approach, which is based on the variability of water advance between the furrows.
11 Beekma, J. 1993. Soil salinization and sodification in tubewell irrigated fields of Punjab, Pakistan: Mission report. Mission report to IIMI-Pakistan, 31 July - 6 August 1993. i, 12p.
Soil salinity ; Tube wells ; Salinity control ; Field tests ; Simulation models ; Calibrations / Pakistan / Punjab
(Location: IWMI-HQ Call no: P 2994 Record No: H013721)
12 Reichman, G. A.; Doering, E. J.; Benz, L. C. 1986. Water management effects on N-Use by corn and sugarbeets. In American Society of Agricultural Engineers, Transactions of the ASAE: Special edition - Soil and Water, Vol.29. St. Joseph, MI, USA: ASAE. pp.198-202.
Field tests ; Surface irrigation ; Water table ; Water management ; Maize ; Crop yield ; Fertilizers ; Nitrogen ; Field tests / USA / Dakota
(Location: IWMI-HQ Call no: 631.4 G000 AME Record No: H04862)
13 Stegman, E. C. 1986. Efficient irrigation timing methods for corn production. In American Society of Agricultural Engineers, Transactions of the ASAE: Special edition - Soil and Water, Vol.29. St. Joseph, MI, USA: ASAE. pp.203-210.
(Location: IWMI-HQ Call no: 631.4 G000 AME Record No: H04716)
14 Kanwar, R. S.; Colvin, T. S.; Melvin, S. W. 1986. Comparison of trenchless drain plow and trench methods of drainage installation. In American Society of Agricultural Engineers, Transactions of the ASAE: Special edition - Soil and Water, Vol.29. St. Joseph, MI, USA: ASAE. pp.456-461.
Subsurface drainage ; Performance evaluation ; Crop yield ; Water table ; Maize ; Soyabeans ; Drains ; Field tests / USA
(Location: IWMI-HQ Call no: 631.4 G000 AME Record No: H05462)
15 Chu, S. T. 1986. Determination of green-ampt parameters using a sprinkler infiltrometer. In American Society of Agricultural Engineers, Transactions of the ASAE: Special edition - Soil and Water, Vol.29. St. Joseph, MI, USA: ASAE. pp.501-504.
(Location: IWMI-HQ Call no: 631.4 G000 AME Record No: H013848)
16 Fipps, G.; Skaggs, R. W. 1986. Effect of canal seepage on drainage to parallel drains. In American Society of Agricultural Engineers, Transactions of the ASAE: Special edition - Soil and Water, Vol.29. St. Joseph, MI, USA: ASAE. pp.1278-1283.
Canals ; Seepage ; Drainage ; Water table ; Infiltration ; Soils ; Mathematical models ; Simulation ; Field tests
(Location: IWMI-HQ Call no: 631.4 G000 AME Record No: H013860)
17 Singh, R.; Satyanarayana, T. 1994. Automated field irrigation system using side weirs. Journal of Irrigation and Drainage Engineering, 120(1):48-59.
Weirs ; Design ; Flow channels ; Flow discharge ; Irrigation systems ; Field tests ; Computer techniques
(Location: IWMI-HQ Call no: PER Record No: H013877)
An automated side weir irrigation system is designed using the concept of constant specific energy. The characteristics of the spatially varied flow along a main channel with multiple side weir outlets are analyzed to determine the roughness coefficient of the channel pertinent to spatially varied flow. A computer program is developed to obtain the geometric parameters of the uniformly discharging weir outlets in a side weir irrigation system. The discharge in the main channel, desired discharges over the weir outlets and the hydraulic and geometric characteristics of the main channel are the main inputs to the computer program. The experiments conducted to evaluate the performance of the developed system show that the deviations of observed discharges from desired ones over the side weir outlets are within 5% for majority of the test runs and in no case these are greater than 10%.
18 Jadhao, S. L.; Keskar, P. B.; Turkhede, A. B.; Shinde, V. U. 1992. Studies on irrigation and phosphorus requirement of Berseem (Trifolium alexandrinum L.) PKV Research Journal, 16(1):54-56.
Crop yield ; Fodder ; Irrigation scheduling ; Soil-water-plant relationships ; Water use efficiency ; Field tests / India
(Location: IWMI-HQ Call no: P 3323 Record No: H014005)
19 Fontaine, T. A.; Todd, D. E. 1993. Measuring evaporation with ceramic Bellani plate atmometers. Water Resources Bulletin, 29(5):785-795.
Evaporation ; Evapotranspiration ; Measuring instruments ; Monitoring ; Calibrations ; Water loss ; Field tests / USA
(Location: IWMI-HQ Call no: PER Record No: H014068)
Ceramic atmometers were tested to determine their usefulness for measuring evaporation in water resources applications. Field experiments were used to evaluate the precision, responsiveness to a range of potential evaporation conditions in a forested catchment, and interpretation of water loss of Bellani plate atmometers. The experiments, conducted from April to October in a warm, humid climate in the southeastern United States, indicate that atmometers can be reliable monitoring instruments for estimating potential evaporation. The small size, portability, low internal thermal mass, low cost, and ability to integrate the effect of radiation, air temperature, humidity and windspeed into one direct measurement of potential evaporation, make atmometers a useful instrument for certain water resources applications.
20 Dahlblom, P. 1993. Simulation of contaminated groundwater migration in fractured rock by a laminar pipe-flow model. Water Resources Journal, 178:53-63.
(Location: IWMI-HQ Call no: PER Record No: H014044)
In this paper, the ability of a laminar pipe-flow model to reproduce the hydrodynamic transport of contaminated groundwater in fractured rock is investigated. It is assumed that the cross-section areas are circular and that the flow is laminar. The molecular diffusion is neglected as well as the impact of variations in velocity over the cross-section area. It is assumed that the cross-section areas in an ensemble of tubes have a gamma distribution. The model is applied to field tracer experiments at two sites. It is shown that the mean size of the cavities is smaller, deeper into the ground and that the distribution is narrower. Different values of the parameter of the gamma distribution were used to reproduce the breakthrough course at the different sites. It was shown that there is no general relation between conductivity of a porus medium and its porosity when the pore size distribution is not taken into account.
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