Hydrochemical response during storm events in a South African mountain catchment: the influence of antecedent conditions

Abstract

The influence of different antecedent conditions on hydrochemical response during storm events was investigated in a small, south-western Cape mountain catchment. Winter and summer storms (four in total) were sampled both before and after the catchment was deliberately burnt. During winter storms, discharge responded rapidly to rainfall, and direct runoff represented the major component of streamflow. Marked lags were observed between rainfall and discharge peaks during the summer storms, and streamflow was dominated by delayed interflow. Chloride, PO: --P and NO, -N exhibited variable response to discharge according to seasonal variations in soil-moisture levels, whereas the response of HCOq , H' and NH2 -N was not influenced by season. The movement of ions appears to be affected more by geochemical processes operating within the soil than by plant-uptake dynamics, as the prescribed burn appeared to have little effect on relationships between ionic concentration and discharge. The findings of the study highlight the complexity of relationships between solute concentration and discharge.

Behavior of dissolved radiocesium in river water in a forested watershed in Fukushima Prefecture

“…As one of the influential solutes, we cannot make mention of the elution effects of NH 4 + because it is under the detection limit (<0.006 mg/L) in many samples. Conversely, relatively high concentrations of K + were observed during summer and in storm events, which was typical for forest areas [ Ávlia et al ., ; Britton et al ., ; Muraoka and Hirata , ]. This is because K + is generated by the elution of organic materials.…”

Streams in Mediterranean Climate Regions: Abiotic Influences and Biotic Responses to Predictable Seasonal Events

“…Shrubs and herbaceous plants often predominate on exposed banks, particularly in areas impacted by humans, and their richness increases in exposed streambeds of intermittent streams (56). Although riparian vegetation of humid regions cannot withstand even mild fires (121), vegetation along mediterraneantype streams is frequently exposed to natural and human-made fires (22,23,158,168) and therefore may be more fire-adapted and show more rapid recovery after fire.…”

Delineation of management regions for South African rivers based on water chemistry

“…It is well known, for instance, that TDS, and even the proportions of the major constituents, change rapidly and predictably in any stream during a single spate (see, for instance, Britton et al, 1993). Where rainfall is seasonal, as it is over most of South Africa, there may also be predictable differences in water chemistry from wet season (winter: May-September in the south-west of the country) to dry season (also winter, in the north and east), although the magnitude of these effects is not known.…”