Abstract
To examine the temporal variation in the amount of roof deposit, which is one of the main non-point sources in urban areas, and its association with dry fallout, a continuous monitoring of roof-deposit environments is performed by a modeled-stormwater sampling (MOS) technique, by which one can easily obtain deposits from a model roof under simulated rainy conditions. The results indicate that the amount of sediment on the roof ( SSroof ) decreases rapidly just after a rainfall and then increases gradually until the next rainfall occurs. The temporal variation in SSroof is similar to that in the accumulated value of the deposition rate of SPM (suspended particulate matter), ∫DSPM dt. The correlation coefficient between SSroof and ∫DSPM dt is 0.839, showing that the mutual relationship between them is sufficiently estimated. Note that to obtain an accurate evaluation of roof-deposit load, it is necessary to use ∫DSPM dt, in which the influences of antecedent fine weather conditions and dry fallout are explicitly incorporated.
