When designing trickle irrigation systems in sloped fields, the use of pressure-compensating (PC) emitters is generally preferred to ensure the emitter distribution uniformity regardless of the land topography and the variable operating pressures. However, the cost of PC emitters is generally higher than non-pressure-compensating (NPC) ones; moreover, the compensating membrane installed inside the emitters can lose elasticity due to the exposition to solar radiation, water quality, and chemical applications. Recently, the irrigation laboratory (IRRILAB) version 1.0 software application was developed to design microirrigation systems for rectangular and planar sectors when using NPC emitters under any field slope and by neglecting the local losses due to the emitter connections. The objective of this work is to demonstrate that even in sloped fields and neglecting the local losses, it is possible to use NPC emitters by maintaining acceptable values of field distribution uniformity. In addition, the influence of local losses caused by the emitters installed in the laterals is also investigated to assess their role in the examined applications. The IRRILAB software was initially used to design a microirrigation sector, to suggest the optimal operating pressure, and to simulate the operating pressure heads and flow rates. The latter values were compared with the corresponding values measured in the field. The software was additionally assessed based on a second experimental campaign, after limiting the length of the laterals to account for local losses. For both experimental campaigns, the values of the commonly used uniformity coefficients were deemed acceptable according to the American Society of Agricultural Engineering (ASAE). However, the introduction of minor losses in the hydraulic design showed an improvement in terms of the emitters’ flow rate distribution in the whole sector and uniformity coefficients.

Flow field characterization in high-aerated flows often involves flow imaging techniques through transparent sidewalls, and the results may be subject to sidewall effects and thus differ from the central flow behaviors. This paper contributes an experimental investigation of the sidewall effects on the air-water flow distributions in quasi-two-dimensional hydraulic jumps in a rectangular flume. The tested hydraulic jumps are characterized by preaerated approach flows and large inflow Froude numbers from 10.6 to 15.1. The air-water flow properties are measured intrusively along the centerline, sidewall, and transverse cross sections to provide a three-dimensional view of the aerated flow structure. Substantial redistribution of the bubbly flow is observed due to the presence of lateral aeration boundary layers in the high-speed jet-shear region, compared to the less affected free-surface roller. The magnitude difference between the central and lateral air-water flow properties is more distinct in terms of bubble count rate and less evident for void fraction and interfacial velocity, while the affected area is broader for void fraction distributions. The results suggest a concentration of high-speed jet flow in the central bottom flow column, where the jet layer is thicker, the recirculation roller is smaller, and the proportion of small-size bubbles is higher. The width of the central flow region free of the sidewall effects is approximately 60% to 80% of the flume width in the present facility, narrower on the bottom, and broader at the free surface. The findings demonstrate that the transverse variation of air-water flow and the difference between the central and lateral flow fields should not be ignored for the high-speed flow regions of hydraulic jump. A correct assessment of the sidewall effects is essential for interpreting imaging-based measurement of highly-aerated flow.

The effects of geometrical parameters (crest height, number of cycles, and plan weir configuration), are investigated experimentally on labyrinth weirs, over a range of headwater ratios of 0.1 to 0.6. Trapezoidal and triangular weirs have a constant angle α=15°, whereas rectangular weirs have the same footprint size B as the trapezoidal configuration. Data uncertainties are quantified at a relatively small overall average of 1.88%. For taller labyrinth weirs, current experimental models achieve lower discharge coefficients when all other geometrical parameters are kept the same. Increasing the number of cycles also leads to a reduction in flow rate and discharge coefficient. These hydraulic performance reductions were most significant for trapezoidal followed by rectangular and triangular configurations. For the same geometrical conditions, a rectangular configuration had a higher flow rate for each head, followed by trapezoidal and then triangular. Nappe behaviors were significantly different between the configurations, whereas modifying the geometrical ratios had less significant effects on the flow characteristics of each configuration.

This study detailed a novel semicoupled method for estimating the three-dimensional vertical velocity profile in an open channel with submerged flexible vegetation. A modified form of the two-dimensional shallow water equations coupled with the drag forces of the vegetation was derived by balancing the flux gradient and the source term. The bending profile of the flexible stems of different flow events was calculated based on the large cantilever beam theory. The vertical velocity profile in the free water and vegetation layers was estimated using Shannon’s entropy and Reynold’s stress equation theory, respectively. The derived semicoupled model was tested to replicate two popular laboratory flume experiments. The results showed that the model accurately predicted the velocity profiles under different flow conditions and patch density. The R2 values of 0.76 and 0.81 indicate that the proposed model is well established and can be applied in complex flow scenarios.

Determining the pipe diameter is one of the principal problems encountered in designing and analyzing pipe flow lines. However, the direct determination of a pipe’s diameter is not possible because of the implicit form of the Colebrook resistance flow formula through commercial pipes. Traditionally, the pipe diameter is determined using a trial procedure. In this paper, the pipe diameter problem was solved using explicit equations in terms of the Lambert W-function. The maximum relative errors of the developed solutions are less than 0.013% for the rough and smooth flow regimes and less than 0.8% and 0.6% for the transition flow region between them. In addition, a method for determining pipe diameter under uncertainty, including design graphs, is presented. It is hoped that the developed solution for predicting pipe diameter will be helpful in the analysis of pipe flow and the design of pipelines and water distribution networks.

In the task of storm sewer design, the accuracy of the method of choice for estimating the risk value is not a trivial task, because it improves the safety and effectiveness of the entire system. Hence, two methods for risk assessment of a storm sewer in an urban area are presented here. The first method is fuzzy risk analysis, in which uncertainty parameters are treated as fuzzy numbers. To do so, a novel formula to calculate the fuzzy risk of sewer flooding with the aim of implementing the alpha-cut principle when runoff and the Manning roughness coefficients are the only uncertainty parameters, is introduced here. The fuzzy number represents the runoff coefficient obtained from the data from seven rainfall events recorded in an experimental urban catchment. In the second method, the fuzzy numbers are replaced with various associated probability distributions, in which all the possible combinations are considered. Then, the Monte Carlo simulation (MCS) technique calculates the corresponding probabilistic risk of flooding. It is observed that computing the limit values of the MCS produces an interval that closely tracks values of the calculated risk using the fuzzy technique. This means that the fuzzy alpha-cut and MCS methods provide similar results and indicate that the fuzzy method for storm sewer risk assessment has acceptable accuracy (more than 97%). But, the representation of uncertainty and the computation time is different in these methods. Hence, the superiority of one method over another depends on the nature of the problem.

Traditional land development stormwater management replaces natural pervious surfaces with impervious surfaces such as pavements and buildings. This increases the rate of runoff that is typically then managed through drainage systems and controlled at or near the site discharge location. This approach often leads to increases in total runoff volume, which can lead to higher peak flows in downstream stormwater systems. Low impact development (LID) technologies, such as porous pavements and green roof systems, provide an alternate approach to managing site runoff by mimicking the pervious surfaces they replace. However, these technologies are often used alongside traditional stormwater infrastructure because their entire hydrologic benefit has not been fully explored. Herein we examine the reduction in peak discharge and total runoff volume achieved through the use of porous pavements and green–blue roof systems (a green roof with an underlying storage volume) on three land developments located on the coastal plain of South Carolina. Model results show that the inclusion of green–blue roof systems can significantly reduce peak discharge compared to traditional roof systems and common modular green roof systems, although they have negligible impact on the total volume discharged. Porous pavements significantly reduce total volume discharged, even when placed over low infiltration soils, but have less impact on peak flow depending on their design. The implementation of LID technologies has the potential to improve site performance beyond standard design rainfall depths, indicating that the use of LID may offset the impact of climate change–induced increases in extreme rainfall event depth and intensity.

A transition is typically required in irrigation canals, laboratory flumes and many other waterways. The warped type transition (WTT) is the preferred link structure between a small rectangular and relatively large trapezoidal channel section. However, the best method of determining the WTT geometry still requires evaluation. This paper provides an analytical function for the three-dimensional (3D) WTT geometry. This was achieved by solving a Dirichlet problem for Laplace's equation. The boundary conditions in the problem were chosen based on guidelines and recommendations from earlier studies of transitions. Solving the problem analytically yields a harmonic function. The geometry given by this function guarantees a streamlined rectangular-trapezoidal link and avoids sharp corners. The streamlined transition would work to reduce flow separation and head loss. This paper contributes to the development of a new method for fabricating WTT with precision and repeatability. The harmonic function can generate geometrical data as essential input for laboratory-scale and field-scale WTTs and can aid in the construction of a three-dimensional model for use in computational fluid dynamic models.