To support the hydrological assessment of Alpine ecosystems, we studied the suitability of the SWAT model to simulate neotropical alpine grasslands or so-called Andean Paramo. Given the paucity of observational data in paramo catchments, data-driven models are usually underutilized, and their outcomes are arguable. However, our research examined if SWAT can reasonably represent the hydrological response of grassland-dominated paramo catchments under data-abundance conditions. Therefore, we set up a soil-based SWAT model that emphasized the role of the soil in the hydrological response and the dominance of saturation excess surface runoff over infiltration excess. Specifically, we incorporated detailed characteristics of Andean soils by horizons, parameterized SWAT to replicate high infiltration rates and high lateral flow in the hillslopes, and restricted groundwater interactions to replicate local streamflow responses. Our soil-based modeling approach reasonably reproduced daily discharge during dry and wet periods throughout the year and the cumulative occurrence of high and low flows. The ratio of precipitation and simulated runoff and the partitioning of the total runoff into the lateral flow and surface runoff were physically meaningful. More significantly, SWAT was able to simulate saturation excess overland flow, which is dominant compared to infiltration excess, and it is a distinctive characteristic of paramo catchments. Based on the overall model performance, we conclude that SWAT can reasonably simulate the hydrological response of Andean paramo catchments, and therefore, its application can extend to similar tropical alpine catchments. Nevertheless, the model showed limitations for simulating low flows.

In Belgium, IWVA uses Managed Aquifer Recharge (MAR) to recharge the aquifer with treated wastewater generated from the communities to sustain the potable water supply on the Belgian coast. This MAR facility is faced with a challenge of reduced infiltration rates during the winter season when pond water temperatures near 4 °C. This study involves the identification of the predominant factor influencing the rate of infiltration through the pond bed. Several factors including pumping rates, natural recharge, tidal influences of the North Sea and pond-water temperature were identified as potential causes for variation of the recharge rate. Correlation statistics and linear regression analysis were used to determine the sensitivity of the infiltration rate to the aforementioned factors. Two groundwater flow models were developed in visual MODFLOW to simulate the water movement under the pond bed and to obtain the differences in flux to track the effects of variation of hydraulic conductivity during the two seasons. A 32 % reduction in vertical hydraulic gradient in the top portion of the aquifer was observed in winter causing the recharge rates to fluctuate. Results showed that water temperature caused a 30 % increase in hydraulic conductivity in summer as compared to winter and has the maximum impact on infiltration rate. Cyclic variations in water viscosity, occurring because of seasonal temperature changes, influence the saturated hydraulic conductivity of the pond bed. Results from the models confirm the impact on infiltration rate by temperature influenced hydraulic conductivity.