Evaluating the hydrological characteristics of the Santa Katarina valley system

Abstract

The study aims to assess the stormwater capacity of the SKV, through the use of field and bench studies. Situated within the GCS, this valley features a diverse land use and is predominantly composed of GL, and as a result, significantly influences hydrological processes. The site was selected due to its potential for groundwater recharge attributed to the presence of various water retention dams. The study employed a combination of methods, including drone surveys, gauge board installations, and infiltration tests, alongside generated models to measure the volume of water reaching the watercourse and being retained by the dams for various REs. Results were used to estimate runoff coefficients of catchments draining to the various retention dams, and the proportion of water retained which infiltrated into the ground and that lost to evaporation:-Through the analysis of results, it was evident that for large REs, significant precipitation, generally above 10 mm – 20 mm, was necessary for notable increases in volume. Recharge typically occurred within a short time frame after REs. Upon comparing infiltration test results with standing water level data, it was evident that LCL had both a higher porosity and permeability than GL. Observations emphasised differences in water level responses across the studied basins, with data from the groundwater monitoring site in the vicinity (< 1 km) showing potential interactions between the Valley and the underlying groundwater aquifer. The Penman equation was chosen to evaluate evaporation from an open water surface since it provided a better understanding of how the climatic data influences the water retained in the basins (0 mm/day – 14 mm/day). Generated models and runoff coefficients, compared with literature, provided a clear breakdown of RE dynamics. Similar to many studies, numerous limitations such as image interpretation challenges and uncertainty regarding uncontrollable conditions were noted.