Relationship between hydrological, physical and chemical characteristics present in rainwater runoff sediments

The objective of this work was to establish possible relationships between rainfall characteristics and physical and chemical characteristics of sediments in an experimental catchment in Bogota city (tropical mountain Andean region). The sediments were collected fortnightly for five months, from the two sand traps of the constructed wetland of the Pontificia Universidad Javeriana, Bogota. We collected the sediments with traps specially designed for the study site. The results show a mean diameter (D50) of 128 mu m, mean concentrations of Cr = 36 mg/kg, Cu = 115 mg/kg, Pb = 273 mg/kg and Zn = 1173 mg/kg. We found a relationship between rainfall and sediment characteristics, which eventually could guide practices for sediment usages: (i) a reduced number of dry days is related to higher particle diameters and lower concentrations of metals; (ii) higher magnitudes of rainfall intensities and total heights are related to a lower number of particles with large grain sizes reaching the sand traps.