The thermal characteristics of the hyporheic zone reflect complex relationships between hydrological, climatological, sedimentological and topographical parameters that occur over a range of spatial and temporal scales. This thesis defines hyporheic temperature profiles, focusing on the influence of meteorology, hydrology and geomorphology; and examines the ecological implications. A pilot study, using a chemical technique to determine temperature profiles of average monthly water temperature to a depth of up to 85 cm in the River Wissey, Norfolk showed that substratum characteristics have a significant influence upon hyporheic temperature patterns. A strong seasonal pattern was defined at all sites with hyporheic temperatures being relatively warm in winter and cool in summer. Temperature ranges within the hyporheic were decreased (4.6-7.7 °C) compared with those of surface waters (10 and 10.9 °C) between February and October 1992. Miniature dataloggers provided high resolution temperature information on the regulated River Blithe, Staffordshire. Data demonstrated that riffle topography produced distinct longitudinal hyporheic temperature patterns in relation to exchanges of channel and groundwater within the hyporheic zone. Riffle heads were 2.26 °C warmer and 1.29 °C cooler than riffle tails hi July and December 1994. Spatial and temporal changes in sedimentological and hydrological factors disrupted the longitudinal pattern of channel and groundwater interactions within the river bed. Increased channel discharge during January and February 1995 decreased hyporheic temperatures by up to 5 °C in areas previously influenced by warmer groundwater. Detailed hydrometeorological monitoring comparing a riffle-pool-riffle sequence highlighted the significance of the river bed as an energy store/source with up to 24% of daily energy exchanges occurring at the channel bed. The magnitude of energy transfers to and from the river bed displayed a high degree of spatial and temporal variability. The thesis concludes with a discussion of the significance of the results and the implications for ecological processes, flow regulation and abstraction, and climate change.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:633089 |
| Date | January 1997 |
| Creators | Evans, Edward Craig |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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