Journal of Irrigation and Drainage Engineering

Drowning fatalities in traffic accidents often occur at roadway sag curves or depressed sections. An increasing concern is how to quickly and safely remove the stormwater from low points of urban area roadways. In accordance with the green concept of Low-Impact-Development, in which a drainage system is designed to pass the full spectrum of runoff flows, this paper presents a new algorithm to improve the highway underpass drainage design for both safety and hydraulic efficiency. It is recommended that the underpass drainage facility be composed of two systems: an underground sewer line be sized to collect the minor storm event through gravity and a pump system be prepared to lift the excess water during a major storm event. Although the pump system in practice may be a permanent station or a mobile unit, the pump system prepared for a highway underpass must be documented in the emergency operational instructions. To design such a drainage system for multiple storm events, all individual drainage elements are to be sized individually, and then the entire drainage system must be evaluated under the tailwater effects. In this paper, a design example is presented to illustrate how to apply two hydrologic methods, including the rational method used to size the sewer pipes and sump pumps and the EPA Storm Water Management Model 5 was adopted to verify the performance of the proposed system under minor and major storm events, respectively.

The smallest flows that can be rated using a distributed-type hydraulic rating, which must rely on head- and tailwater stages monitored at local stilling wells, are limited by the combined measurement uncertainty of the head drop. In this study, we show that for low head drops, a rating based on index-velocity (IV) methods provides more accurate flow estimates at uncontrolled culverts than a hydraulic rating. To contrast the accuracies of these two rating approaches to rate flows under very low head drops, we calibrated both types of ratings for an uncontrolled culvert in a constructed wetland using concurrent measurements of water stages in local stilling wells, index-velocities by a Doppler shallow-water meter, and flow rates by an acoustic Doppler flow meter (ADFM). Further, to measure head-drops lower than those that can be estimated based on data from the stage sensors in standard wells, we used a portable pressure-differential sensor with a higher resolution and sampling rate. Using the portable head-drop sensor allowed us to extend the lower limit of the head-drop to which the hydraulic rating can be accurately applied, from 1.51 cm (based on stages from the standard wells) to 0.31 cm. This, in turn, extended the range of uncontrolled full-pipe flows that can be rated by the hydraulic rating at the study site from $\sim 0.45{\mathrm{m}}^3/\mathrm{s}$, based on stages monitored at standard wells, to $\sim 0.2{\mathrm{m}}^3/\mathrm{s}$, based on the high-resolution head-drop sensor. In contrast, we found that the IV rating can rate a flow as low as $0.14{\mathrm{m}}^3/\mathrm{s}$ without the need of stilling wells—about 60% and 30% lower than the hydraulic rating can rate with stages from the stilling wells and the portable sensor, respectively. Moreover, the IV rating could rate flows contributing to $\sim 94\%$ of the total annual volume at the study site accurately, while the volume accurately estimated at these sites by the hydraulic rating using stilling wells is less than half of that.

Artificial turf with black infill material gained widespread use on athletic fields starting in the early 2000s. One argument made in the desert southwestern United States for replacing natural grass–based athletic fields with artificial turf surfaces is that water is not needed for irrigation. However, it has been shown that in arid and semiarid climate zones the surface temperature of the artificial turf fields can exceed 80°C during the summer, requiring irrigation and drainage systems to keep them cool enough for use. An experiment was conducted at New Mexico State University to evaluate the amount of water required to maintain surface temperatures comparable to those of natural turfgrass areas. A mathematical model was developed based on the heat balance equation to determine heat dissipation from artificial turf–based fields with comparison of the predicted values to experimental data. Overall, our model estimates were within 12% of the measured values. The model indicates that over a $24\text{-}\mathrm{h}$ period, the amount of water (3.00 to 5.00 mm) required to maintain artificial turf at temperatures similar to irrigated natural turfgrass are comparable.

This paper presents a retrofit for vortex settling basins (VSBs) by perforating the deflector to reduce sediment deposition and thereby lowering VSB failure risks. Experiments were conducted for two retrofitted VSBs with the deflector perforated on the outside overflow area only and the other entirely perforated. The sediment deposition, sediment trapping efficiency, and water abstraction ratio of the retrofitted VSBs were measured and compared with an original VSB with an unperforated deflector. The VSB with a partially perforated deflector exhibited a similar sediment trapping efficiency and water abstraction ratio to the original VSB, with an average reduction over 40% in sediment deposition on the deflector. The VSB with an entirely perforated deflector had a lower sediment trapping efficiency and greater sediment deposition on the deflector.