Study of pollutant washoff from small impervious experimental plots

rebecca.killalea@canberra.edu.au on 02 Mar 2022
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Author(s)
Vaze, J., & Chiew, F. H. S.
Year
2003
Title
Study of pollutant washoff from small impervious experimental plots
Source
Water Resources Research
DOI
10.1029/2002WR001786
Volume
39
Issue
6
ISSN/ISBN
0043-1397
Abstract

An understanding of the pollutant washoff process in urban catchments is essential to develop appropriate models for estimating storm water pollutant washoff loads. This paper investigates the relative importance of the raindrop and runoff energies in the pollutant washoff process by carrying out field and laboratory experiments. Two similar test surfaces are used, with simulated rainfall allowed to fall directly onto one surface, while insect screens are placed above the other surface to remove the rainfall energy. The results indicate that both the turbulence created by falling raindrops and the shear stress imparted by surface runoff are important in loosening the surface particles and suspending them in water, making them available for washoff. The energy of falling raindrops in detaching the surface pollutants is very important at the start of an event and is less dominant as the availability of easily detachable and transportable fractions of the surface pollutant decreases over the storm. Analyses of data from the experimental runs and from actual catchments also suggest that meaningful characteristic curves that relate event total suspended solids (TSS) and total phosphorus (TP) loads to storm durations for specific rainfall intensities can be developed from the experimental data.

Evidence

Cause Effect Response measure type Habitat Country Modified
Hydrology - other
Rainfall
Water quality - nutrients (other) (Increase)
The energy from rainfall was shown to have an effect on pollutant loads in runoff, attributed to the energy in rainfall causing pollutants to be dislodged from the surface. The experiment compared a surface affected by rainfall and runoff with a surface only affected by runoff and found rainfall to have a notable impact on the pollutant wash-off loads. Note that no statistical result was stated in the paper to evaluate this relationship or determine effect size/significance.
Other Artificial Australia 02-Mar-2022
Hydrology - surface flow (timing) (Increase)
Increasing storm duration
Water quality - suspended material/sediment (Decrease)
The TSS concentration was highest at the start of the simulated runoff and decreased over time.
Other Artificial Australia 02-Mar-2022
Hydrology - surface flow (timing) (Increase)
Increasing storm duration
Water quality - nutrients (phosphorus) (Decrease)
The TP concentration was highest at the start of the simulated runoff and decreased over time.
Other Artificial Australia 02-Mar-2022
Hydrology - surface flow (timing) (Increase)
Increasing storm duration
Water quality - nutrients (nitrogen) (Decrease)
The TN concentration was highest at the start of the simulated runoff and decreased over time.
Other Artificial Australia 02-Mar-2022