Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Abstract:

Previous study of the temporal and spatial distribution of limestone solution at Cooleman Plain rested on monthly discharges and water analyses of the Blue Waterholes over 4 years. For this study automatic recording of discharge (8 years), rainfall (8 years), evaporation (7 years) and temperature (4 years) was attended by variable success in the face of interference, rigorous climate and inaccessibility. The most important aspect of the climatic data was the support obtained for the earlier assumption of similar water balances in the forested igneous frame and the grassland limestone plain. Runoff was again shown to be highly variable from year to year and to have an oceanic pluvial regime, with a summer-autumn minimum owing much to evapo-transpiration. The flow duration curve from daily discharges puts this karst amongst those where neither extremely high nor low flows are important. The stream routing pattern offsets the effect of 71% of the catchment being on non-karst rocks, damping flood events. An inflection of 700 l/s in a flow duration plot based on discharge class means is interpreted as the threshold at which surface flow down North Branch reaches the Blue Waterholes. Storages calculated from a generalised recession hydrograph parallel Mendip data where baseflow (fissure) storage provides most of the storage and quickflow (vadose) storage only a secondary part. Water-filled conduit storage (the phreas) could not be determined but is considered small. The baseflow storage seems large, suggesting that it can develop independently of caves in some measure. A quickflow ratio for floods derived by Gunn's modification of the Hewlett and Hibbert separation line method appears relatively low for a mainly non-karst catchment and is again attributed to the routing pattern. For analysis of variation of the solute load over time, estimates of daily discharge during gaps in the record where made for the author by Dr. A.J. Jakeman and Mr. M.A. Greenaway (see Appendix). A small number of discharge measures of two contrasted allogenic catchments of the igneous frame shows a unit area yield close to that for the whole catchment. Together with the guaging of most of the allogenic inputs, this supports the idea that the water yield is much the same from the forested ranges and the grassland plain. This is important for the estimation of limestone removal rates.