Drip-screen rainfall simulators for hydro- and pedo-geomorphological research: the Coventry experience

Abstract

Seven case studies are presented, demonstrating the successful use of a laboratory-based drip-screen rainfall simulator at Coventry University to investigate several hydrological, pedological and geomorphological problems. The results of previously unpublished studies are presented in full, while the salient points of published studies are discussed. Synthesis of the experimental results led to the recognition of various philosophical and practical problems associated with the realistic simulation of rain, which need to be addressed in future research. Particular problems are posed by the variety of analytical approaches and simulator designs, as they impede meaningful inter-laboratory comparisons. It is argued that future improvements require optimization, harmonization and standardization of analytical procedures and rainfall simulators. An ideal approach would be the development of a European key laboratory to offer realistic and standardized simulation conditions.

Development and testing of a large, transportable rainfall simulator for plot-scale runoff and parameter estimation

“…The literature on rainfall simulators is extensive; for a more complete review see Battany and Grismer (2000). The standard small-or laboratory-scale (1 m 2 or smaller) rainfall simulator is a drip tank (Cerdà et al, 1997;Foster et al, 2000;Fernandez-Galvez et al, 2008, and many others). These devices are tanks with a uniform arrangement of holes.…”

“…They can produce a wide range of rainfall intensities and typically provide spatially and temporally uniform coverage. The 0.5 m 2 simulator of Foster et al (2000) produced intensities ranging from 7.74 to 28.57 mm h −1 with temporal coefficients of variation for intensity ranging from 5.04 to 11.55 %, and the 0.24 m 2 rainfall simulator of Cerdà et al (1997) produced 55 mm h −1 with a spatial uniformity coefficient of 93 %. Larger intensities are also possible; for example Fernandez-Galvez et al (2008) used a simulator with a range of 0-120 mm h −1 with an intentionally heterogeneous distribution.…”

“…3, consists of six 2 m vertical beams, three 4 m horizontal beams to which the nozzles are mounted, and two 4 m horizontal beams to complete the frame, for overall measurements of 4 m × 4 m × 2 m. The present frame uses 6 cm metal tubing with clamp connectors since they were readily available, but other materials may be used; Schedule 40 PVC is a good inexpensive alternative. Additionally, a plastic mesh attached to the final two horizontal beams helps randomize the spray pattern (Foster et al, 2000). The mesh is a heavy-gauge 4 mm grid mesh that is doubled along the edges to prevent ripping and attached to the frame using plastic mesh clips and zip ties to prevent sagging.…”

“…The results of these experiments are typically used for the purposes of understanding processes such as runoff and infiltration mechanisms, water routing, and sediment generation and transport at scales ranging from point to hillslope, with emphasis on how surface characteristics such as slope, aspect, soil properties, fire, vegetation, and microtopography affect these processes (e.g., Dunne et al, 1991;Bhardwaj and Singh, 1992;Foster et al, 2000;Stone et al, 2008;Fernandez-Galvez et al, 2008).…”

A mathematical model for evaluating the effect of wind on downward-spraying rainfall simulators

“…A more cost-effective alternative is to use rainfall simulators to apply controlled rainstorms to small plots (Esteves et al, 2000;Foster et al, 2000;Lascelles et al, 2000;Kamphorst, 1987). Portable rainfall simulators used on small plots give sufficient flexibility to study a wide variety of processes (e.g., infiltration, irrigation, interrill erosion and water quality) on different soils and slopes for a wide range of land uses (Fig.…”