Your search found 44 records
1 Rayej, M.; Wallender, W. W.. 1987. Furrow model with specified space intervals. Journal of Irrigation and Drainage Engineering, 113(4):536-548.
Mathematical models ; Furrow irrigation ; Surface drainage ; Surface runoff ; Water scarcity ; Mathematical models
(Location: IWMI-HQ Call no: PER Record No: H03674)
2 Wallender, W. W.; Rayej, M. 1990. Shooting method for Saint Venant equations of furrow irrigation. Journal of Irrigation and Drainage Engineering, 116(1):114-122.
(Location: IWMI-HQ Call no: PER Record No: H06009)
3 Wallender, W. W.. 1988. Simulated furrow irrigation design with a uniform and nonuniform soil. In Proceedings of the International Conference on Irrigation System Evaluation and Water Management, Wuhan, China, 12-16 September 1988: Vols.1 & 2. Wuhan, China: Wuhan University of Hydraulic and Electrical Engineering. pp.558-575.
(Location: IWMI-HQ Call no: 631.7.8 G000 PRO Record No: H06698)
4 Tod, I. C.; Wallender, W. W.; Henderson, D. W.; Devries, J. J. 1990. Considerations for sizing water delivery systems. Irrigation and Drainage Systems, 4(2):171-179.
(Location: IWMI-HQ Call no: PER Record No: H07196)
5 Howitt, R. E.; Wallender, W. W.; Weaver, T. F. 1990. Economic analysis of irrigation technology selection: The effect of declining performance and management. In Sampath, R. K.; Young, R. A. (Eds.) Social, economic and institutional issues in third world irrigation management. Boulder, CO, USA: Westview Press. pp.437-464. (Studies in water policy and management, no.15)
(Location: IWMI-HQ Call no: 631.7.8 G000 SAM Record No: H08009)
6 Wallender, W. W.; Ardila, S.; Rayej, M. 1990. Irrigation optimization with variable water quality and nonuniform soil. Transactions of the ASAE, 33(5):1605-1611.
(Location: IWMI-HQ Call no: P 1999 Record No: H08706)
7 Tod, I. C.; Grismer, M. E.; Wallender, W. W.. 1991. Measurement of irrigation flows through irrigation turnouts. Journal of Irrigation and Drainage Engineering, 117(4):596-599.
(Location: IWMI-HQ Call no: PER Record No: H08811)
8 Waller, P. M.; Wallender, W. W.. 1991. Infiltration in surface irrigated swelling soils. Irrigation and Drainage Systems, 5(3):249-266.
(Location: IWMI-HQ Call no: PER Record No: H09261)
9 Renault, D.; Wallender, W. W.. 1992. ALIVE (Advance Linear Velocity): Surface irrigation rate balance theory. Journal of Irrigation and Drainage Engineering, 1992. 118(1):138-155.
(Location: IWMI-HQ Call no: PER Record No: H009916)
(1.13 MB)
10 Bautista, E.; Wallender, W. W.. 1992. Hydrodynamic furrow irrigation model with specified space steps. Journal of Irrigation and Drainage Engineering, 118(3):450-465.
(Location: IWMI-HQ Call no: PER Record No: H010392)
11 Childs, J. L.; Wallender, w. W.; Hopmans, J. W. 1993. Spatial and seasonal variation of furrow infiltration. Irrigation and Drainage Engineering, 119(1):74-90.
(Location: IWMI-HQ Call no: PER Record No: H012119)
12 Bautista, E.; Wallender, W. W.. 1993. Numerical calculation of infiltration in furrow irrigation simulation models. Journal of Irrigation and Drainage Engineering, 119(2):286-294.
(Location: IWMI-HQ Call no: PER Record No: H012403)
13 Bautista, E.; Wallender, W. W.. 1993. Identification of furrow intake parameters from advance times and rates. Journal of Irrigation and Drainage Engineering, 119(2):295-311.
(Location: IWMI-HQ Call no: PER Record No: H012404)
14 Bautista, E.; Wallender, W. W.. 1993. Reliability of optimized furrow-infiltration parameters. Journal of Irrigation and Drainage Engineering, 119(5):784-800.
(Location: IWMI-HQ Call no: PER Record No: H013360)
The reliability of furrow-infiltration parameters computed from advance measurements was analyzed. Lumped parameters were obtained using the least-squares approach. The objective function was formulated using advance time and velocity observations as a function of distance. Predicted values were calculated with a finite difference hydrodynamic model with wetted perimeter-dependent infiltration. The extended Kostiakov equation was used to describe infiltration-rate variation with time. Reliability was examined by comparing recorded total intake and runoff with values predicted with the single average parameters. Results showed that reliability of coefficients depends on the relationship between infiltration variability, furrow length, and inflow rate. In particular, relatively short irrigation times hampered the identification of the steady infiltration rate. Spatial trends in infiltration rates affected the reliability of parameters as well. The magnitude and nature of the resulting prediction errors was found to be dependent on the direction of the trend relative to the flow direction. In general, velocities appeared to provide better estimates of average infiltration characteristics than advance times but weighted least squares may be required to compute the parameters from field data.
15 Bautista, E.; Wallender, W. W.. 1993. Optimal management strategies for cutback furrow irrigation. Journal of Irrigation and Drainage Engineering, 119(6):1099-1114.
(Location: IWMI-HQ Call no: PER Record No: H013680)
The optimal management of a cutback-furrow-irrigation system with spatially variable infiltration based on an average intake function was analyzed. The problem was formulated as a cost-minimization function subject to meeting a specified fraction of the irrigation requirement. Optimal solutions were examined in the context of developing a real-time control system for furrow irrigation. Although total infiltration was adequately predicted with the average function, final water distribution was not. Consequently, the optimal policies resulted in actual requirement efficiencies less than the target value. Nonetheless, relative changes in performance as a function of the constraint were well predicted. The performance index was relatively insensitive near the optimum, and cutback time had the least impact on application efficiency and uniformity. Satisfactory performance was therefore still obtained by reducing the inflow after the final advance time. Similar values of application efficiency were generally computed with decreasing application depths, but smaller efficiency resulted when the optimized cutoff time was less than the final advance time. There were small performance differences between discrete and continuous-time cutback functions.
16 Hanson, B. R.; Wallender, W. W.. 1986. Bidirectional uniformity of water applied by continuous-move sprinkler machines. In American Society of Agricultural Engineers, Transactions of the ASAE: Special edition - Soil and Water, Vol.29. St. Joseph, MI, USA: ASAE. pp.1047-1053.
(Location: IWMI-HQ Call no: 631.4 G000 AME Record No: H013855)
17 Renault, D.; Wallender, W. W.. 1994. Furrow advance-rate solution for stochastic infiltration properties. Journal of Irrigation and Drainage Engineering, 120(3):617-633.
(Location: IWMI-HQ Call no: PER Record No: H014420)
(1.01 MB)
A flow-balance equation of surface irrigation is used to solve, section by section, the advance problem on heterogeneous soils. The advance-linear-velocity (ALIVE) solution as a function of time is a sum of exponential terms. Within a section, the properties are uniform, and two linear relationships between the advance rate x '(t) and the distance x(t) result. The inverse problem is solved step by step, identifying the Horton infiltration law of the studied section from the record of the velocity and the knowledge of the infiltration in the previous sections. Theoretical examples and field experiments are compared. When applying a standard evaluation approach, assuming a uniform infiltration function to an heterogeneous soil misleading results can occur. Perturbations in the advance rate can lead to an incorrect infiltration function when using either the standard ALIVE or Kostiakov-based hydrologic models. However, a nonstandard ALIVE procedure is feasible since the distinction between the sections having different infiltration properties can be detected. To apply the velocity analysis, a high density of advance points is required.
18 Lamacq, S.; Wallender, W. W.. 1994. Soil water model for evaluating water delivery flexibility. Journal of Irrigation and Drainage Engineering, 120(4):756-774.
Soil water relations ; Water delivery ; Simulation models ; Evapotranspiration ; Percolation ; Furrow irrigation ; Irrigation scheduling ; Water allocation / USA / California
(Location: IWMI-HQ Call no: PER Record No: H014965)
19 Eching, S. O.; Hopmans, J. W.; Wallender, W. W.; MacIntyre, J. L.; Peters, D. 1994. Estimation of local and regional components of drain-flow from an irrigated field. Irrigation Science, 15(4):153-157.
Furrow irrigation ; Groundwater ; Percolation ; Evapotranspiration ; Subsurface drainage ; Water table
(Location: IWMI-HQ Call no: PER Record No: H015695)
20 Purkey, D. R.; Wallender, W. W.. 1994. A review of irrigation performance assessment in California. Irrigation and Drainage Systems, 8(4):233-249.
Irrigation management ; Performance evaluation ; Performance indexes ; Water supply ; Water delivery ; Water conveyance ; Environmental sustainability ; Environmental effects / USA / California
(Location: IWMI-HQ Call no: PER Record No: H016414)
A survey of irrigation performance assessment as conducted in California was performed. Emphasis was placed on the actual procedures employed by the State's major water providers and irrigation districts. Survey results covered the development of innovative irrigation performance assessment parameters as well as the methodologies used to evaluate these parameters. All aspects of California's irrigation infrastructure were considered, from the management of major hydraulic structures, through water delivery, and on- farm consideration. Environmental performance assessment methodologies were also examined.
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