Comparison of varied complexity models simulating recharge at the field scale

Abstract

Numerical models are frequently used for the regional quantification of groundwater recharge. However there is a wide range of potential models available that represent the land surface with varying degrees of complexity, but which are rarely tested against observations at the field scale. We compared four models that simulate potential recharge at four intensively monitored sites with different vegetation and soil types in two adjacent catchments. These models were: Penman–Grindley, UN Food and Agricultural Organization, SPAtial Distributed Evaporation and Joint UK Land Environment Simulator. Standardized, unoptimized land surface datasets and pertinent literature were used for parameterization to reflect practice in regional water resource management and planning in the UK. The models were validated against soil moisture observations at all sites, as well as observed transpiration and interception and calculated total evaporation over a year at a woodland site. Soil moisture observations were generally reproduced well, but there were significant differences in how the models apportioned precipitation through the hydrological cycle. This demonstrates that soil moisture data alone are not a good diagnostic for groundwater recharge models. Significant differences in potential recharge were produced by models at both grassland sites, although simulated average annual potential recharge varied by only 15% at the grassland site on permeable soil. At the woodland sites, soil moisture contents were reproduced least accurately, and there were large differences in potential recharge at both woodland sites. This predominantly resulted from varied and inaccurate simulation of evaporation, particularly in the form of interception losses where this was explicitly represented in models. Differences in model structure, such as runoff representation, and parameter selection also influenced all results. Hydrological Processes © 2013 John Wiley & Sons, Ltd.

The influence of model structure on groundwater recharge rates in climate-change impact studies

“…This is why all simplified groundwater recharge models perform well for historical years with average temperature ranges and precipitation amounts but performance is different for extremes. These observations are in line with the study of Sorensen et al (2014). They show a generally good agreement between simulated and observed soil moisture content for four soil-water-balance models but significant differences occur under extreme periods and in the seasonal patterns.…”

Uncertainty of groundwater recharge estimated from a water and energy balance model

“…Hence, the choice of a model needs to be based on the objective of a project and availability of datasets. As pointed out by Alley (1984), Gee and Hillel (1988) and Sorensen et al (2014), models that treat soil layers as several reservoirs are likely to produce differing recharge estimates, because of different approaches used for water budget partitioning. Sorensen et al (2014) demonstrated that soil moisture data alone are unable to constrain groundwater recharge in four commonly used water balance models, consistent with our study.…”

Glacio-hydrological melt and runoff modelling: a limits of acceptability framework for model selection

“…Even so, to satisfy the water balance, an explicit representation of the soil zone for model nodes that are not ice or snow-covered was included using the method developed by Griffiths et al (2006) which has been successfully applied to temperate regions in the past (Mackay et al, 2014;Sorensen et al, 2014) and is based on the well 30 established UN Food and Agricultural Organisation soil water balance method (Allen et al, 1998 defines the maximum volume of water available to plants for evapotranspiration after the soil has drained to its field capacity and can be defined from lookup tables with basic information on vegetation and soil information (Allen et al, 1998). This was parametrised using the 'Talus' soil class and 'semi-vegetated' land surface class giving an average T AW value of 7 mm.…”