Seasonal water temperature variations in response to air temperature and precipitation in a forested headwater stream and an urban river: a case study from the Bukhan River basin, South Korea

Abstract Seasonal water temperature variations in response to air temperature and precipitation were examined in a forested headwater stream (Yeonyeop stream, YS) and an urban river (Bukhan River, BR) within the same basin. In both sites, precipitation and air/water temperatures were monitored from April to November of 2017 and 2018. The differences between air and water temperatures were 4–6 °C higher in the YS than the BR during the summer and fall seasons. Air temperature and precipitation exhibited seasonal differences with no apparent spatial variations; however, water temperature alone varied both seasonally and spatially. Mean temperature elasticity in the YS was greater than that in the BR, whereas mean precipitation elasticity in the YS was lower than that in the BR. Additionally, temperature elasticity increased with water temperature, whereas precipitation elasticity increased with decreases in water temperature, albeit only during the summer. From an elasticity standpoint, our findings suggest that water temperature in a forested headwater stream is more sensitive to air temperature changes than that in an urban river.