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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 2/15/2006 Publication Date: 4/4/2006 Citation: Green, T.R. 2006. Spatial scaling of surface water infiltration and its implications for estimating groundwater recharge. Meeting Abstract.Intl. Symposium on Groundwater Resources Assessment under the Pressures of Humanity and Climate Change. Kyoto, Japan, April 4-6, 2006. Interpretive Summary: The GRAPHIC Project has identified priority research topics related to groundwater recharge, discharge, storage, and water quality. This presentation focuses on some physical aspects affecting spatial groundwater recharge estimation and uncertainty associated with spatial variability. Previous work has shown the importance of quantifying plant water use based on vegetation response and soil hydraulic properties. Consequently, the effects of climate change on deep seepage and groundwater recharge vary with the vegetation and soils. The present study illustrates the potential complexities added by spatial variability of infiltration rates and associated soil properties based on field measurements. Our field experiments include 150 sorptivity and steady infiltration measurements taken at ten landscape positions with nested patterns of variability. The field site is an undulating agricultural terrain cropped with winter wheat under conventional tillage. No irrigation has been applied to the study area, but pivot irrigation is commonly applied in the region of eastern Colorado, USA. In addition to quantifying the observed spatial variability in soils and infiltration rates, inferences will be made for scaling up measurements from 30-cm diameter rings to areas on the order of 30-m by 30-m for each landscape position. Furthermore, process-based modeling of infiltration and its scaling behavior under different soil scaling in space will be discussed. These results are intended to shed new light on research needed to address spatial variability of soils and interactions between land areas when modeling infiltration and recharge under different climates and land management strategies. Technical Abstract: The GRAPHIC Project has identified priority research topics related to groundwater recharge, discharge, storage, and water quality. This presentation focuses on some physical aspects affecting spatial groundwater recharge estimation and uncertainty associated with spatial variability. Previous work has shown the importance of quantifying plant water use based on vegetation response and soil hydraulic properties. Consequently, the effects of climate change on deep seepage and groundwater recharge vary with the vegetation and soils. The present study illustrates the potential complexities added by spatial variability of infiltration rates and associated soil properties based on field measurements. Our field experiments include 150 sorptivity and steady infiltration measurements taken at ten landscape positions with nested patterns of variability. The field site is an undulating agricultural terrain cropped with winter wheat under conventional tillage. No irrigation has been applied to the study area, but pivot irrigation is commonly applied in the region of eastern Colorado, USA. In addition to quantifying the observed spatial variability in soils and infiltration rates, inferences will be made for scaling up measurements from 30-cm diameter rings to areas on the order of 30-m by 30-m for each landscape position. Furthermore, process-based modeling of infiltration and its scaling behavior under different soil scaling in space will be discussed. These results are intended to shed new light on research needed to address spatial variability of soils and interactions between land areas when modeling infiltration and recharge under different climates and land management strategies. |
