Influences of Urban Discharges and Urban Heat Effects on Stream Temperature

Urban areas with dark and impermeable surfaces are known to have a heating effect on air still water compared surrounding areas, called the urban heat island (UHI). UHI stormwater discharges’ collective impact stream temperature, especially regarding seasonal changes, is less-studied field. In this study, temperature of village Aarslev Stream Vindinge in Southern Denmark was examined. Loggers (ID A–L) were placed 2020–2021, measuring (°C) pressure (kPa). Outlets analyzed respect origin: Direct outlets (rain ÷ basin), delayed by ponds + common overflow, sewage from WWTP. Data showed rise through all months (except March) 0.3–1.9 °C, most notably summer months. A one-way ANOVA confirmed that upstream station downstream K significantly different (p-values < 0.001). No significant difference temperatures between outlet types found. An increase observed response rain events, followed decrease. This assumed be “first flush”. speculated mean less optimal conditions for trout sensitive macroinvertebrates not because shock, but rather lower O2 concentrations higher mineralization. River lake projected increase, might become more pronounced. decrease after (station L). Therefore, it concluded due UHI.