The geomorphic character and hydrological function of an upland swamp, Budderoo plateau, southern highlands, NSW, Australia

Abstract

Upland swamps are a form of topogenous mire that occur on the plateau areas of eastern Australia. These systems are well recognized for their ecological value, but little is known about their internal hydrological function and how this relates to their geomorphic structure and evolution. In this study, the geomorphic, sedimentological, and hydrological properties of an intact upland swamp on the Budderoo Plateau NSW are investigated. The geomorphic structure of the swamp is simple, and the sedimentology comprises basal layers of coarse sands, overlain by several layers of organic accumulation up to 3.3 m in thickness. Each of these sedimentary units has different hydrological behaviors (rates of water throughflow and discharge) that drive the overall function of the swamp in response to rainfall of various magnitudes and duration. Four hydrological response types have been identified in the functioning of this swamp. These response types (RT) are characterized by different peaks and recession responses to rainfall. The form of the hydrograph produced is controlled by antecedent water table position and the amount, timing and duration of rainfall. Depending on antecedent moisture conditions, the swamp can operate either as a store for water or as a rapid conduit for water throughflow and overland flow.