Research output: Contribution in Book/Report/Proceedings - With ISBN/ISSN › Chapter (peer-reviewed)
Research output: Contribution in Book/Report/Proceedings - With ISBN/ISSN › Chapter (peer-reviewed)
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TY - CHAP
T1 - Flow Path Dimensionality and Hydrological Modelling
AU - Chappell, Nick
AU - Ternan, J. Les
PY - 1993
Y1 - 1993
N2 - Increasingly, research is indicating that subsurface flow paths govern ion transport within river catchments. Distributed prediction of these solute flow paths in typically heterogeneous catchments must inevitably be highly uncertain without some identification of a spatial structure relating small-scale measurements of soil properties to flow predictions distributed over large catchments. To date, the evidence for profile and catenal structure within soil hydrological properties and resultant solute flow paths is not fully embraced by the hydrologica community. As a consequence soil parameters are often poorly distributed within catchment-scale distributed models. This paper seeks, first, to generalize the disparate sources of evidence of parameter and flow paths structure within the profile-ward and catena-ward dimensions. Second, to outline how much of this structure has been incorporated into previous hydrological simulations using distributed models, and third, to examine the physical basis of attempts to simply parameter and flow paths dimensions using pedological classifications. The available evidence suggests that a considerable number of world soils show profile-ward structure within their hydrological properties and resultant flow paths. Changes in profile-ward patterns along catenal sequences remain uncertain. The Plynlimon region of mid-Wales has been the focus for many detailed studies of solute flow paths, catchment-scale model simulations, soil property characterizations and soil classification. Comparison of these studies suggests that most model simulations and hydromorphic classifications of soil taxa fail to distinguish adequantely between soil horizons and soil types with markedly different property distributions. Preliminary analysis, however, suggests that by using a catena based criterion to classify the hydromorphic characteristics of soils, soil elements with distinct patterns of properties anf flow paths can be identified. This might suggest that the accuracy of distributed predictions of ions movements within river catchments could be greatly improved by the derivation of profile-specific patterns of soil properties. These profile-specific effective parameters need to be derived from measurements over a range of scales, including individual layers, profiles and complete catenas.
AB - Increasingly, research is indicating that subsurface flow paths govern ion transport within river catchments. Distributed prediction of these solute flow paths in typically heterogeneous catchments must inevitably be highly uncertain without some identification of a spatial structure relating small-scale measurements of soil properties to flow predictions distributed over large catchments. To date, the evidence for profile and catenal structure within soil hydrological properties and resultant solute flow paths is not fully embraced by the hydrologica community. As a consequence soil parameters are often poorly distributed within catchment-scale distributed models. This paper seeks, first, to generalize the disparate sources of evidence of parameter and flow paths structure within the profile-ward and catena-ward dimensions. Second, to outline how much of this structure has been incorporated into previous hydrological simulations using distributed models, and third, to examine the physical basis of attempts to simply parameter and flow paths dimensions using pedological classifications. The available evidence suggests that a considerable number of world soils show profile-ward structure within their hydrological properties and resultant flow paths. Changes in profile-ward patterns along catenal sequences remain uncertain. The Plynlimon region of mid-Wales has been the focus for many detailed studies of solute flow paths, catchment-scale model simulations, soil property characterizations and soil classification. Comparison of these studies suggests that most model simulations and hydromorphic classifications of soil taxa fail to distinguish adequantely between soil horizons and soil types with markedly different property distributions. Preliminary analysis, however, suggests that by using a catena based criterion to classify the hydromorphic characteristics of soils, soil elements with distinct patterns of properties anf flow paths can be identified. This might suggest that the accuracy of distributed predictions of ions movements within river catchments could be greatly improved by the derivation of profile-specific patterns of soil properties. These profile-specific effective parameters need to be derived from measurements over a range of scales, including individual layers, profiles and complete catenas.
M3 - Chapter (peer-reviewed)
SN - 0471938866
T3 - Advances in Hydrological Processes
SP - 121
EP - 139
BT - Terrain Analysis and Distributed Modelling in Hydrology
A2 - Beven, Keith J
A2 - Moore, I.D.
PB - John Wiley and Sons
CY - Chichester
ER -