TY - JOUR
T1 - Simulation modellling of water movement in a cracking clay soil
AU - Bradley, Christopher
AU - Mosugu, ME
AU - Gerrard, Anthony
PY - 2005/12/1
Y1 - 2005/12/1
N2 - This paper describes the development and application of a simple empirical model describing differences in water movement through a cracking clay soil at Brimstone Farm, Wiltshire, UK. An extended data set comprising readings of soil water tension has been collected from an area of 9 m(2) instrumented with 4 nests each of 3 tensiometers. The cracks are responsible for considerable differences both in water pathway and flow magnitude. Variations in water flow suggested by changes in soil-water tension are described by a model developed using 'ModelMaker' and applied separately to each profile nest. The model envisages water flow to occur through three soil layers, and to be partitioned into matrix and macropore flow components. Water is lost via drainage to clay tile drains at 60 cm depth. Water flow between layers is described as a function of the hydraulic gradient using Darcy's Law, with additional drainage from structural voids within the soil. Differences in the effective hydraulic conductivity describing slow and rapid flow components equate to macro and matrix flow for each tensiometer profile. The results illustrate heterogeneous patterns of flow through a soil block and demonstrate that a comparatively simple model is able to represent satisfactorily water flow dynamics through a cracking clay soil.
AB - This paper describes the development and application of a simple empirical model describing differences in water movement through a cracking clay soil at Brimstone Farm, Wiltshire, UK. An extended data set comprising readings of soil water tension has been collected from an area of 9 m(2) instrumented with 4 nests each of 3 tensiometers. The cracks are responsible for considerable differences both in water pathway and flow magnitude. Variations in water flow suggested by changes in soil-water tension are described by a model developed using 'ModelMaker' and applied separately to each profile nest. The model envisages water flow to occur through three soil layers, and to be partitioned into matrix and macropore flow components. Water is lost via drainage to clay tile drains at 60 cm depth. Water flow between layers is described as a function of the hydraulic gradient using Darcy's Law, with additional drainage from structural voids within the soil. Differences in the effective hydraulic conductivity describing slow and rapid flow components equate to macro and matrix flow for each tensiometer profile. The results illustrate heterogeneous patterns of flow through a soil block and demonstrate that a comparatively simple model is able to represent satisfactorily water flow dynamics through a cracking clay soil.
U2 - 10.1079/SUM2005337
DO - 10.1079/SUM2005337
M3 - Article
SN - 1475-2743
SN - 1475-2743
VL - 21
SP - 386
EP - 395
JO - Soil Use and Management
JF - Soil Use and Management
ER -