Artificial rainfall is widely used to study the surface runoff process but several problems are related to the reproducibility of natural rainstorms. A new rainfall simulator and a collection system were designed and tested in laboratory and in the field. The rainfall simulator consists of four independent lines of low-cost pressure washing nozzles operated at a pressure of 80 mbar which number and position causes the rainfall intensity delivered on the plot. The spatial rainfall distribution and intensity were measured with 63 rainfall gauges covering the whole plot . The Joss Waldvogel Disdrometer was used to characterize the rainfall produced by the rainfall simulator. The drop size distribution was obtained. The drop size spectrum ranges from 0.25 5 mm to 3.3 mm and its shape is the same that one produced by a natural rainfall. The rainfall intensity varies from approximately 31 to 62 m mm/h and it is sufficiently patially uniform (Christiansen's coefficient of uniformity i s 0.62 to 0.75) over the plot. Field tests were carried out on a grassy field with silt-loam soil in Orroli, Sardinia in July and August 2010. The values of the mean rainfall intensities obtained from field data are in accord with the laboratory values. The field site measurement includes the surface runoff, evaluated using a dedicated tipping bucket flow meter, and the soil water content measured throughout the field experiments. The results showed the good performance of this new rainfall simulator that offers the possibility to reproduce natural rainfall to gather parameters needed for hydrologic modeling. The entire designed system offers the possibility to carry out reliable measurements of the surface runoff under different rain intensities and also allows one to me a a sure this on diifferent temporal scales by taking into account the different environmental conditions.
On the estimation of surface runoff through a new plot scale rainfall simulator in Sardinia, Italy
D'ADDERIO, Leo Pio;PORCU', Federico;
2013
Abstract
Artificial rainfall is widely used to study the surface runoff process but several problems are related to the reproducibility of natural rainstorms. A new rainfall simulator and a collection system were designed and tested in laboratory and in the field. The rainfall simulator consists of four independent lines of low-cost pressure washing nozzles operated at a pressure of 80 mbar which number and position causes the rainfall intensity delivered on the plot. The spatial rainfall distribution and intensity were measured with 63 rainfall gauges covering the whole plot . The Joss Waldvogel Disdrometer was used to characterize the rainfall produced by the rainfall simulator. The drop size distribution was obtained. The drop size spectrum ranges from 0.25 5 mm to 3.3 mm and its shape is the same that one produced by a natural rainfall. The rainfall intensity varies from approximately 31 to 62 m mm/h and it is sufficiently patially uniform (Christiansen's coefficient of uniformity i s 0.62 to 0.75) over the plot. Field tests were carried out on a grassy field with silt-loam soil in Orroli, Sardinia in July and August 2010. The values of the mean rainfall intensities obtained from field data are in accord with the laboratory values. The field site measurement includes the surface runoff, evaluated using a dedicated tipping bucket flow meter, and the soil water content measured throughout the field experiments. The results showed the good performance of this new rainfall simulator that offers the possibility to reproduce natural rainfall to gather parameters needed for hydrologic modeling. The entire designed system offers the possibility to carry out reliable measurements of the surface runoff under different rain intensities and also allows one to me a a sure this on diifferent temporal scales by taking into account the different environmental conditions.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
