A predictive hydrological model for temporary freshwater rockpools

Abstract

A predictive hydrological model for freshwater rockpools. Emma Cassar. Temporary freshwater rockpools of the Maltese Islands are found on karst terrain where they form in isolated kamenzitas (solution hollows). The only inputs of water are from direct precipitation and from intercepted surface runoff whilst water loss occurs through overflow and evapotranspiration. The area under study was that of San Pawl tat-Targa which is composed of karst terrain. Thirteen pools were chosen from this site to be monitored for a period of 6 months. Simultaneously controlled treatments were set up to represent the pools and were monitored for 8 months. Each treatment had 2 groups were one group was placed under direct sunlight and the other group in the shade. These included Drying Treatment, Replenishment Treatment and the Natural Cycle Treatment each of which were refilled with water or left in their natural state. Correlation and Partial least Squares Regression (PLSR) were used to analyse the parameters which effect the change in water level of the pools and treatments. The correlation results showed similarity where both the pools and treatments were not significantly correlated with temperature, relative atmospheric humidity and gust wind speed. PLSR showed that weekly rainfall had an affect on the water level of treatments more than temperature change. Change in temperature and weekly rainfall affected the change in water level for most pools. The predictive model was constructed using SIMILE v5.4 where the lack of other measured parameters did not produce an accurate result. The basic framework of the model is correct but requires more parameters and time for the results to model a natural situation, work is still in progress.