The aim of this work is to discuss the distribution of Oligochaeta (Annelida) in the Danube River using the collections made by the Joint Danube Survey 2007 (JDS2) on more than 2800 km of the river. The basic faunistical features of the oligochaete assemblages were analysed with regard to three main sectors of the Danube (upper, middle and lower reaches, the last with the Danube Delta). A total of 52 oligochaete taxa have been recorded. Most of the observed species are typical of the potamon-type rivers in the region, and are well adapted to moderate-to-high organic load. The highest taxa richness and frequency of occurrence were observed among the Tubificidae family. Naididae, Propappidae, Enchytraeidae and Haplotaxidae had also low frequency. The upper reach of the Danube showed the lowest species richness, while the middle reach is characterised by its highest species richness. Construction of dams and regulation of the riverbed have resulted in an increase of limno(rheo)philic taxa which prefer slow-flowing and lentic zones.
The intensities of short-duration rainfall events are fundamental inputs to the design of stormwater management infrastructure. However, since stormwater infrastructure must function as designed for many decades, if there are long-term trends in rainfall intensities, design storms need to be modified. Evidence demonstrates, using data from 13 rain gauges in Ontario, that storm intensities relevant to urban stormwater (5 year) appear to have changed over the last 30 years. The resultsshow, for example, statistical significance at 80% confidence that the 5-year storm has increased, and 85% that the 2-year storm has increased, for the 1 h storm in Waterloo, using partial duration series (PDS) data. The PDS data indicate intensities are increasing at a rate of 1-3% per year. Results show, for example, that a 5-year recurrence storm for PDS for the period 1970-1984 is now very close in magnitude to a 2-year recurrence storm for the period 1985-2003 for Waterloo, Ontario. The implications for a case study demonstrate that 5 out of 12 storm sewer pipes in a subdivision would need to be increased in diameter to obtain the same level of stormwater performance.
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