Variations in solids loadings to roadside gully pots

Abstract The contribution and composition of road surface particulate loadings as received by roadside gully pots is assessed together with the influences of rainfall and highway surface runoff characteristics. Sediments are well sorted with almost 90% of sediment grading curves lying within a narrow distributional band. Organic grading curves show a distinct diminution in grain sizes, with 10% organic material and 25% bitumen content associated with particulates less than 60 microns. Sediment removal rates showed a seasonal variation which was strongly influenced by both rainfall and surface flow characteristics. The antecedent dry period length appears to have only a minor affect upon the availability of road surface sediments.