Microthermal gradients, involving signi®cant variations in temperature over distances of a few centimetres to a few metres, were investigated in the water column and substratum of the River Frome and Bere Stream in Dorset, UK, which are groundwater dominated streams fed by chalk aquifers. In many of the sections surveyed, strong lateral contrasts of up to c. 7 8C were evident as a consequence of solar heating of shallow channel margin zones and thin surface layers isolated by¯oating vegetation from the main body of¯ow. Shading by instream, emergent and riparian vegetation, and by river banks also caused signi®cant microthermal gradients in the water column. Detailed logging of temperatures in the substratum at selected sites revealed damping of variation with increasing depth below the bed surface, seasonal reversal in bed temperature gradients and considerable local variation in the substratum temperature pro®les of a pool-rie sequence. The latter did not conform to the pattern expected from advective heat transfer associated with downwelling of water at the rie head and upwelling at the tail, and measurements of interstitial¯ow velocities and particle size suggested more complex¯ow circulation and heat transfer. There was some evidence that the microthermal gradients identi®ed were of ecological signi®cance.

Mining processes alter natural landscapes worldwide, and methods for restoration of mined areas are widely studied. Establishment of vegetation is essential to mined land restoration. Prior research has addressed vegetative influence on erosion and runoff, but effects of vegetation type on surface hydrologic processes are less studied. We measured infiltration rates and observed subsurface flow paths in mine soils on a reforested area and a grassed area on a former surface coal mine in the eastern United States. The two areas were constructed and reclaimed fourteen years prior to our study using processes similar in all aspects except vegetation. MiniDisk tension infiltrometers and Brilliant Blue FCF dye staining analyses were utilized to evaluate near-surface flow processes in the vegetated mine soils. Mean infiltration rates were 16.

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