Wpływ częstotliwości pomiarów transportu fluwialnego na określenie jego wielkości i dynamiki podczas wezbrań w zlewniach o zróżnicowanym użytkowaniu na przykładzie rzeki Silnicy i Sufraganiec (Kielce)

A major problem in the quantitative hydrological studies, especially fl uvial, might be dealing with assessment of methods and results basing on error analyses. As for the mountain and Upland Rivers, the most common source of the errors could be low frequency of measurements and collection of samples. These particular studies have been carried out for the 8 sectors (sub-catchments) of the Silnica and Sufraganiec catchments of different use. The urban catchments of the river Silnica has been spread over 49.40 km2, and agricultural-woodland catchments of Sufraganiec has embraced 62.01 km2. During 11 high rivers’ stands, of variable origin, a few parameters have been determined, i.e. single unit outfl ow, concentration of suspended matter, concentration of dissolved matter, and temperature of the river waters every hours for the summer months and every two hours for the winter months. All the daily values of the above mentioned parameters have been compared with those values at 7 o’clock every day, and calculated mean values for the particular high rivers’ stand. Maximum error for the values of single unit outfl ow has been highly variable compare to the other values, being in the range of 65.4 to 873%. The highest spatial variability of the mean error of the measurements has been observed during high rivers’ stands related to the convection rains, whereas the smallest spatial variability of that error has been noted during high rivers’ stands due to widespread rains. The highest error while assessing our results has been found at the end of the urban catchments (Pakosz, Białogon). Maximum error for the concentration of the suspended matter has changed from 83.6 to 604.5%. Similarly, maximum error for the concentration of the dissolved matter has changed from 80.9 to 132.2%, whereas mean values have shown an error of 98.5 to 101.7%. All the observations have led to a conclusion that error for all the determined values is directly related to the space modifi ed anthropogenically. If that space increases, the error for measuring parameters of the fl uvial transport increases too. It means, that only high frequency of fi eld measurements of the fl uvial transport could reduce the errors while determining parameters of the transport. Ideally, more or less continuous measurements could reveal some complex mechanisms of fl uvial transport.