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Thermal profiles within river beds
Author(s) -
Evans E. C.,
Greenwood M. T.,
Petts G. E.
Publication year - 1995
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.3360090103
Subject(s) - hyporheic zone , hydrology (agriculture) , environmental science , groundwater , surface water , streams , temperature gradient , geology , geography , meteorology , computer network , geotechnical engineering , environmental engineering , computer science
This pilot study uses a chemical technique (KEtX) to establish vertical profiles of average monthly water temperature within river beds: the hyporheic zone at the interface between surface water and groundwater. Data are presented for two gravel‐bed sites and one sand‐bed site on the River Wissey, Norfolk, UK. From February to October 1992, average monthly temperatures were determined at 10cm intervals down 1 m profiles. A strong seasonal pattern was defined at all sites with hyporheic temperatures being relatively warm in winter and cool in summer. Isothermal periods occurred in March‐April and September‐October. Temperature ranges within the hyporheic were decreased (4.6–7.7°C) compared with those of surface waters (10 and 10.9°C). Temperature profiles were similar at all sites during winter, but the sand‐bed site had relatively low temperatures at a standard depth within the hyporheic during summer and the temperature gradient became isothermal later in the autumn at this site. It is suggested that the influence of flows and substratum characteristics on temperature patterns, especially in regulated rivers, may have significant ecological implications, for example for determining the timing of salmonid fry and invertebrate emergence.