Abstract
Considering the spatial and temporal rainfall variability has a significant impact on the accuracy of hydrological models of the stormwater runoff. According to the results of statistical processing of the daily depths of the precipitation layers in Lviv city for the period 1945-2020, a tendency of increasing the annual depth of the precipitation layer is obtained by an average of 1.68 mm/year at the current average annual value of 733.4 mm/year. The average annual number of wet weather days in Lviv systematically decreases
on 0.244 year−1, while the annual amounts of large rainfalls on the contrary increase on 0.129 year−1 for the rainfalls with a daily depth hd ≥ 1 mm and on 0.088 year−1 for hd ≥ 10 mm. For all runoff-forming rainfall events in Lviv, their average annual amount and mean depth of the rainfall increase when considering more recent periods, which confirms the general global trend of increasing the frequency and intensity of the largest storms, regardless of the local trend of annual precipitation change. Using the recommendations of the Ukrainian regulatory document DBN V.2.5-75:2013, a linear correlation of the spatial rainfall intensity variability coefficient
on the total area of the urbanized catchment is obtained. It is indicated that this method does not align with the well-founded and verified in practice fact of the dependence of the spatial rainfall depth and intensity variability coefficients on the return period. A comparative analysis of the actual daily precipitation depths for the 24 largest storms in Lviv and Graz (Austria) in 2017-2018 indicates the similarity of their distribution in both cities so in terms of values as during the seasons. Statistical processing of the data of a network of 16 rain gauges in Graz city yielded maximum coefficients of spatial non-uniformity of rainfall by depth and by intensity as a linear function of the return period, which can be used to estimate spatial rainfall variability in cities with similar climate and a small number of rain gauges
on 0.244 year−1, while the annual amounts of large rainfalls on the contrary increase on 0.129 year−1 for the rainfalls with a daily depth hd ≥ 1 mm and on 0.088 year−1 for hd ≥ 10 mm. For all runoff-forming rainfall events in Lviv, their average annual amount and mean depth of the rainfall increase when considering more recent periods, which confirms the general global trend of increasing the frequency and intensity of the largest storms, regardless of the local trend of annual precipitation change. Using the recommendations of the Ukrainian regulatory document DBN V.2.5-75:2013, a linear correlation of the spatial rainfall intensity variability coefficient
on the total area of the urbanized catchment is obtained. It is indicated that this method does not align with the well-founded and verified in practice fact of the dependence of the spatial rainfall depth and intensity variability coefficients on the return period. A comparative analysis of the actual daily precipitation depths for the 24 largest storms in Lviv and Graz (Austria) in 2017-2018 indicates the similarity of their distribution in both cities so in terms of values as during the seasons. Statistical processing of the data of a network of 16 rain gauges in Graz city yielded maximum coefficients of spatial non-uniformity of rainfall by depth and by intensity as a linear function of the return period, which can be used to estimate spatial rainfall variability in cities with similar climate and a small number of rain gauges
| Translated title of the contribution | TEMPORAL AND SPATIAL UNEVENNESS OF RAINFALL IN MODELING SURFACE RUNOFF FROM URBAN AREAS |
|---|---|
| Original language | Russian |
| Pages (from-to) | 67-73 |
| Number of pages | 7 |
| Journal | Scientific Bulletin of UNFU |
| Volume | 31 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2021 |