The effect of agro-climatic factors on groundwater recharge at Rottnest Island, Western Australia

Abstract

The objective of this paper is to assess the groundwater storage and the effects of land-use and climatic factors on groundwater recharge at Rottnest Island, Western Australia. One-dimensional agro-hydrological model “Soil-Water-Atmosphere-Plant (SWAP)” was used in conjunction with data available from the Bureau of Meteorology, Government of Western Australia and Rottnest Island Authority. Nine scenarios were considered based on the top boundary (vegetation type) and bottom boundary (flux type) of the soil column. The recharge model was calibrated for 2000 -2010 and the results indicate that the groundwater storage at the study area is gradually decreasing over the simulated period. Recharge is found greatly affected by land use pattern. One of the water balance components “ transpiration” was found affecting the groundwater recharge significantly up to 67.7% of rainfall annually from aquifer to atmosphere. Analysis also demonstrated that the relationship between recharge and rainfall is non-linear.