Summary
Freshwater drainage systems, fed by melting of nearby inland-ice and perennial snowdrifts, exist in the south-eastern part of arid, ice-free, coastal Vestfold Hills. Most important is the complex Druzhby system. Intriguing questions arise about the conditions ruling its seasonal development and about the consequences of possible changes of those conditions. A water-balance was calculated for 1990-91. The system went through four seasonal phases of which only one displayed a fully developed external drainage. Evidently, the relative duration of those phases can vary considerably from one year to another. The system depends critically on the water supply from ice-dammed Chelnok Lake, which could readily be drained by a minor retreat of Sørsdal Glacier. Exposed to excessive evaporation, the large Crooked Lake would then become internally drained and reach a new equilibrium in ~830 years. A Crooked Lake sediment core can be interpreted as this occurred during the Holocene. The idea, inferred from striae, of a late Holocene Chelnok Glaciation reaching the northern shores of Crooked Lake is questioned. Instead, it is suggested that the Chelnok striae origin from local basal melting of the ice-sheet draining southward into a deglaciated Sørsdal trough. Presently, runoff is determined by opposing short and long-term climatic influences.