Land use in catchments of small streams and a hydrological urban heat island – a case study in Kielce city (Poland)

Abstract

ABSTRACT This article presents the spatial and temporal value and dynamics of water temperature in small streams flowing through a city of 200,000 inhabitants. The analysis is based on stationary measurements of a water temperature in eight (8) catchment outlets of various uses (including forest, suburban, urbanised). The water temperature was measured daily for 4 years (06 UTC; electronic thermometers; accuracy: 0.1°C). The study has shown that the water temperature in streams is clearly modi fied by the nature of land use prevailing in the catchment, represented by the imperviousness index. Urbanised areas caused a significant increase in minimum, mean and maximum temperature values on a daily, monthly and annual cycle. The determined relationship indicates that every 1% increase in impervious catchment area causes a water temperature increase of 0.1°C. The presented and documented facts justify the use of the term ‘hydrological urban heat island’, which began to appear in the literature.