Journal of Irrigation and Drainage Engineering

In this paper, the outflow process of a weir with an irregular shape is studied using dimensional analysis and the incomplete self-similarity theory. The new unique stage–discharge relationship, which is deduced theoretically, represents a novel and comprehensive equation to describe the weir outflow process for a full range of flow and different geometric variables of weirs, including finite-crested weirs, broad-crested weirs with positive or negative crest slope, broad-crested weirs with an upstream, downstream, or both upstream and downstream crest ramps, and, triangular weirs with an upstream or downstream ramp. Finally the proposed stage–discharge relationship is calibrated using measurements available in literature.

The crop water production function (WPF), representing the relationship between crop yield and seasonal irrigation water, is a useful tool for irrigation planning purposes. The objective of the paper is to propose a methodology to evaluate the optimal seasonal irrigation depth based on the crop production function, the field distribution uniformity, and economic considerations. An extended unpublished database experimentally obtained on the onion crop on the island of Kula, Hawaii, was initially used to assess the crop WPF. The combination between the crop WPF and the model representing the field distribution uniformity allowed determining the area subjected to underirrigation and overirrigation, as well as the corresponding yield, that were finally averaged across the field. An economic comparison was also carried out in order to evaluate the optimal seasonal water depth aimed at maximizing the farmer’s gross margin under different irrigation system distribution uniformities and water prices. According to the experimental data, it was observed that the onion crop is more sensitive to deficit than overirrigation, as well as that a quadratic model, valid for the entire range of the seasonal applied irrigation depths fitted better than a two-slope linear model, representing separately the conditions of deficit and over-irrigation. Moreover, the maximum yield, as well as maximum gross margin, can be obtained by applying average irrigation depths lower than those which correspond to the maximum yield, with percentages that declined at decreasing of water distribution coefficient and at increasing of water price. The proposed methodology can be applied even for other crops once the corresponding WPFs aree known, thus providing interesting evaluations that are useful for irrigation planning.

It is widely recognized that the Hortonian mechanism of runoff generation occurs in arid and semi-arid regions, generally characterized by high rainfall intensity on soils exhibiting low infiltrabilities. Differently, in steeply sloping forested watersheds in humid climates, by infiltrating through a highly permeable upper soil horizon, water moves beneath the soil surface determining a slow response. However, in most real cases, for example when in arid regions mountain forested areas take place, both (quick and slow) runoff generation processes coexist and together contribute to the hydrologic hillslope response. In this paper, based on analytical solutions of the hydrologic response, instantaneous response functions of both quick and slow components are defined, depending on parameters characterizing geometrical and dynamical features at the hillslope scale of immediate physical meaning. For each response component, two characteristic time-scales are defined, the mean holding time spent by a particle in its motion through the hillslope and the so-called time to equilibrium, accounting for a critical rainfall duration generating a maximum discharge at the bottom of the hillslope. Approximated instantaneous response function (IRFs) in the usual form of gamma probability density functions (pdfs) are proposed, which allowed reducing the many parameters appearing in both quick and slow response models to the scale and shape parameters, also incorporating the effect of different antecedent flow conditions. At the basin scale, the collective response of all the hillslopes is described by a representative hillslope, which combined response accounts for the relative dominance of quick and slow response.

This paper deals with the numerical investigation of the drainage efficiency of a continuous transverse gully with the grate’s slots aligned in the flow direction and compared with experimental data sets. The gully efficiency attained with a three-dimensional (3D) numerical model is compared and validated against experimental data. The numerical simulations are performed using a computational fluid dynamics volume of fluid solver. Different slopes, from 0 to 10%, and a wide range of drainage flows, from 6.67 to $66.67\mathrm{L}/\mathrm{s}/\mathrm{m}$, are simulated. The linear relation between Froude number and efficiency of the gully is in agreement to the one experimentally obtained.

Field experiments were conducted in a semiarid region of Punjab state, northwest India, for 2 years to evaluate an efficient irrigation schedule for guava under mulch and no-mulch conditions. The experiment involved the effect of mulching and three irrigation threshold values [$I_1$ ($-20\mathrm{kPa}$); $I_2$ ($-40\mathrm{kPa}$); and $I_3$ ($-60\mathrm{kPa}$)] on guava plants under drip irrigation and fertigation. Soil matric potential, irrigation amount, soil water content, and fertilizer (N, P, and K) content were measured, and seasonal crop evapotranspiration as well as water and fertilizer use efficiency were computed regularly during the growing period of the crop. The calibrated two dimensional (2D)/three-dimensional (3D) model was used to simulate soil matric potential, and water and fertilizer movement in the soil under guava trees for mulch and no-mulch conditions. Simulated water movement, soil matric potential, and N, P, and K movement statistically matched those measured using the tensiometers, soil water probes, and soil sampling techniques. Results show that for mulch plants, if no irrigation was applied for a period extending to 6–7 days, i.e., for $I_3$ ($-60\mathrm{kPa}$), irrigation treatment and dry periods without rainfall, the soil matric potential was lower for mulch plants than for no-mulch plants. Statistical measures [root mean square error (RMSE), average absolute error (AAE), relative root mean square error (RRMSE), correlation coefficient ($r^2$), and model efficiency (EF)] indicate a close correspondence between measured and simulated values. The modeling efficiency (EF) and the root-mean square error (RMSE) for soil matric potential varied from 0.80 to 0.95 and 4.07 to 8.35 kPa, respectively, and for fertilizer movement from 0.61 to 0.87 and 0.0094 to $1.78\mathrm{mg}/{\mathrm{cm}}^{-1}$, respectively. A water and mass balance was performed using commercially available software to estimate the water and fertilizer (N, P, and K) performances and relate these with amount of water and fertilizer applied. Modeling also revealed that lower leaching losses was for $-40\mathrm{kPa}$ soil matric potential. The amount and frequency of irrigation application at this soil matric potential perfectly suited the growth of the plants.

Population growth and socioeconomic changes in developing countries over the past few decades have created severe stresses on the available water resources across the world, particularly in arid and semiarid regions, which are predominant in Iran. Hence, the optimal management of water resources is imperative. Reservoir operation is a challenging problem that involves complexities in terms of nonlinear functions, larger numbers of decision variables, and multiple constraints. Evolutionary or metaheuristic algorithms have become an attractive alternative to the classical methods for solving complex reservoir problems. This paper applies a metaheuristic algorithm named the firefly algorithm (FA) to reservoir operation and demonstrates the superiority of this algorithm against the genetic algorithm (GA), a commonly used optimization algorithm, using (1) five mathematical test functions, (2) the operation of a reservoir system with the purpose of irrigation supply, and (3) the operation of a reservoir system with the purpose of hydropower production. The results demonstrate the superior performance of the FA in terms of the convergence rate to global optima and of the variance of the results about global optima when compared with the results of the GA.

Stormwater regulations require construction-generated pollution to be controlled on-site prior to discharge to avoid impairment of receiving waterbodies. Sediment basins are stormwater detention practices commonly used to capture and treat sediment-laden runoff prior to discharging from a construction site. Federal and state highway and environmental protection agencies have developed standardized guidance on the design of sediment basins, however further research is necessary to understand basin performance under various design conditions using large-scale testing techniques. This study details the design and construction of a $79.0{\mathrm{m}}^3$ (2,790 ${\mathrm{ft}}^3$), large-scale sediment basin at the Auburn University Erosion and Sediment Control Testing Facility (AU-ESCTF). A testing methodology and phased experimental regime were developed to allow for future testing of various sediment basin design configurations and high-rate lamella plate settler technology within the basin. Data collection efforts including water quality, flow rates, basin stage levels, sediment deposition volumes, and sediment sampling for particle characterization will be used to evaluate the performance of various basin design configurations. Preliminary results from basin testing for the effectiveness of an excavated sump are presented to demonstrate the developed test method. Water-quality parameters revealed improvements ranging between 150 and 200 Nephelometric Turbidity Units (14.0–18.6%) when an excavated sump was included in the forebay of the system. Sediment collection showed that the improved system allowed for an additional 4.3% of sediment deposition by mass. This research effort and future testing results will allow practitioners to better understand the performance of current sediment basin designs and for providing operational improvements.

A Lopac gate is one type of upstream control structures in irrigation canals. Advantages of a Lopac gate include performing as an overflow structure, letting sediments and floating bodies pass simultaneously, as well as easy automation. The structure has recently attracted the attention of researchers for detailed investigations. One effective tool to study control structures is a mathematical model. Due to the unsteady nature of flow in irrigation canals, incorporation of the mathematical model of control structures with hydrodynamic models is necessary. In this research, a mathematical model of Lopac gates is developed and linked with the ICSS (irrigation conveyance system simulation) hydrodynamic model. The Lopac gate model was developed as a boundary condition in four subroutines, including steady flow conditions, operation, unsteady flow conditions, and updating information. The developed model is validated using physical model data. The maximum error obtained was 6%, which is acceptable for practical purposes. The model was tested on a canal of DEZ irrigation network in Iran under many different conditions. The results showed that the model is performing well for tested applications and could be used in various studies of irrigation canals equipped with this structure.

Precipitation is one of the main components in water budget balance and its trend analysis could help to understand the hydrological features of a basin in the future. In this study, 10 subbasins in western Iran are selected. One rain gauge station is chosen as a control station and three more are selected upstream, in the middle, and downstream of each subbasin. Average monthly and annual rainfall time series are analyzed and then the trends are investigated. Analysis of mentioned time series of control stations reveals that 51% of time series have decreasing trends, while 49% experience increasing trends. Six out of 10 studied subbasins have decreasing trend of average annual rainfall time series all over the basin. Among the most rainy months in the country (November to May), in November 68% of the stations have upward trend, while in March 92% of the stations have downward trend.

The use of automation controllers for irrigation systems using saline water in irrigated agriculture, as a means of its disposal, was evaluated in a field experiment that was conducted in three successful seasons (2012, 2013, and 2014) at sites at the National Research Center (NRC) farm, Egypt. The purpose of the research was to study the effect of injected saline water (0, 15, and 30%), using three automation controller drip irrigation systems [surface drip (SD) and subsurface drip at both 10-cm (SSD10) and 20-cm (SSD20) soil depths] on the vegetative growth and water productivity (WP) of a wheat variety (Triticum aestivum L. CV. Gemmaiza 9). The results showed that subsurface drip irrigation (SSD20) has a preemptive effect on both wheat grain and straw yield, and the percentage of the increase was 7.11 and 6.12%, respectively, as compared with an automation controller (SD) irrigation system. Additionally, the percentage of the increase was 1.68 and 1.83% compared between automation controller (SSD20) and both (SSD10; SD) irrigation systems for grain and straw yield, respectively. Increasing water salinity to 14.82% reduced WP and straw 11.62 and 16.23%. The reductions were 37.52 and 39.79% of saline water, and 30.23% for same sequences. Responses of wheat growth to water deficits vary depending on the wheat species and growth stages of the plants being used. A highly positive correlation coefficient was attained among wheat plant characteristics, except for water consumption during the growing season of the wheat plant.

Open channels are important water structures for irrigation, water supply, power generation, and drainage. The primary concern of designing a channel is to determine optimum dimensions while minimizing construction costs. In this paper, a memetic metaheuristic algorithms called “shuffled frog-leaping algorithm” (SFLA) is used to optimize sampling design variables of composite open channels. The results of optimization using SFLA and a generic language for interactive general optimization (LINGO) software are compared with other metaheuristic algorithms, such as genetic algorithm (GA), simulated annealing (SA), Lagrange multiplier method (LMM), ant colony optimization (ACO), improved ant colony optimization (IACO), and particle swarm optimization (PSO). Four common nonlinear models in open-channel designing are considered in this study: (1) model I (M1), which applies an equivalent roughness coefficient without any sectional division following the Manning equation; (2) model II (M2), which considers a variation of horizontal velocity over the cross section; (3) model III (M3), which determines minimum construction costs that is constrained on maximum permissible velocities corresponding to different lining materials of the composite channel cross section; and (4) model IV (M4), which imposes additional side-slope constraints over model II. Optimization results using SFLA and LINGO clearly show improvements in objective function in all the studied models. SFLA and LINGO show 14.93 and 12.64% improvement, respectively, in M1 compared to the LMM, GA, ACO, and IACO; 23.43 and 19.03% in M2 compared to GA, ACO, and IACO; 1.34 and 0.63% in M3 compared to GA and ACO; and 26.14 and 21.88% in M4 compared to GA and PSO. An improvement in the objective function is also obtained in SFLA over LINGO by 2.28, 4.40, 0.71, and 4.26%, respectively, in models M1 through M4. This result evidently demonstrates the efficiency of SFLA in optimizing composite open-channel design for increasing economic benefit.

Crossing culverts under highways that run through an alluvial fan is a typical converging kinematic wave flow. Design of such a crossing culvert requires the estimation of peak flow for the selected level of protection. In this paper, it was assumed that the converging kinematic wave flows on the rising hydrograph would move at the constant speed determined by the equilibrium flow depth. The derivation of the analytical solution to predict the rising hydrograph from a given converging culvert entrance is achieved. The simplified analytical solution was further compared with the numerical solutions for several case studies. It was found that the peak flow depends on the rainfall intensity, time of concentration, and location of the culvert entrance on the converging geometry. Although the rising hydrograph does not represent the complete the kinematic wave flow, it does improve the current design methods for the highway crossing culverts under highways through alluvial fans.