Assessing the Impact of Leaf Area Index on Evapotranspiration and Groundwater Recharge across a Shallow Water Region for Diverse Land Cover and Soil Properties

R. Fernandes; S. Wang; A. Simic
Climate and land cover changes impact groundwater resources primarily through changes in net surface recharge. Actual evapotranspiration and the partitioning between runoff and groundwater infiltration govern the rate of aquifer recharge. Remote sensing technology opens up new possibilities for groundwater recharge modeling through a rapid method of acquiring up-to-date information at high spatial resolution over a large geographical area. Using the Ecological Assimilation of Climate and Land Observations (EALCO) model, we assess the importance of remote sensing derived land cover, leaf area index (LAI) and soil texture in estimating evapotranspiration and groundwater recharge within the Oak Ridges Moraine (ORM), a complex groundwater recharge area and major aquifer in south-central Ontario, Canada. We explore temporal and spatial dynamics of hydrological variables of the ORM and perform sensitivity analyses based on remote sensing derived inputs to EALCO. The results indicate that LAI is a critical variable of evapotranspiration calculations for the ORM. Soil texture does not have as significant an impact on evapotranspiration as LAI; it is generally found to be a more efficient moderator of recharge and runoff, especially for the soil texture of very fine sand. Based on our results, afforestation of the ORM region would result in the reduction of annual groundwater recharge at the current average precipitation due to increased evapotranspiration. It would also reduce the runoff within the area due to increased evapotranspiration and infiltration.
Evapotranspiration; Recharge; Leaf Area Index; Remote Sensing; Sensitivity Analysis
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