Flow Resistance in Lowland Rivers Impacted by Distributed Aquatic Vegetation

This study addressed a research concern that employing fixed value for the bed roughness coefficient in lowland rivers (mostly sand-bed rivers) is deemed practically questionable presence of mobile and time-dependent changes vegetation patches. Accordingly, we set up 45 cross-sections four streams to investigate seasonal flow resistance values within year. The results revealed significant sources boundary with lower regime were forms aquatic vegetation. then used discharge as an influential variable reflecting impacts above-mentioned flow. studied approach ended two new predictors which simply connected dimensionless unit factors, Darcy-Weisbach (f) Manning (n) coefficients. A comparison computed measured also indicated 87–89% data sets ± 20% error bands. verified against large independent field flume data. obtained predictions using developed might overestimate factors by 40% other rivers. Based on different view, according findings this research, variation abundance could show augmentation values, both f n, low summer flows when covers river side banks. highest amount was observed during period, July–August period.