Infiltration and Surface Geometry Features of a Swelling Soil following Successive Simulated Rainstorms

Abstract

rangement and distribution of the cracks. Moreover, White (1972) explained the energy implications that The theory of water movement in high shrink/swell soils has expericause the cracks to reappear in the same position from enced consistent revision since Haines first presented the topic in 1923. Several aspects of the infiltration process in cracking soils have event to event. Johnston and Hill (1944) observed that proven to be difficult to measure; seal/crust formation and properties, cracks develop between crop rows where the water concrack network patterns, preferential flow zones and contributions, tent was higher (due to less uptake by plants) and, thus, and soil moisture determinations within the profile (near crack and the strength of the soil was lower. Since dry clay soils near center of prismatic column) to name a few. Here, we used simutend to moisten more rapidly to a greater depth along lated rainstorms, laser measurements of surface elevation, needlea crack than at a distance from a crack, cracks transmit penetrometer measurements, and mass measurements of infiltrating more water deeper under heavy precipitation events, water over a 206-and 145-d period to examine water movement and making the soil wetter in this area. cracking patterns in a large sample box filled with a swelling clay soil.

Threshold behaviour in hydrological systems as (human) geo-ecosystems: manifestations, controls, implications

“…In a combined field and modelling study Graeff et al (2009) explained the second delayed peak by fast displacement of groundwater. In 1974 nearby mining activities started to exploit fluorite deposits at a depth of 190 m and a distance of nearly 1 km and bimodal rainfall-runoff events vanished almost completely (Wenk, 2000). Graeff et al (2009) explained this change in hydrological functioning by groundwater pumping activity that significantly lowered groundwater levels in this area.…”

“…In temperate climate regions normal shrinkage is the most relevant mechanism, where volume reduction is approximately proportional to the water loss (Chertkov, 2000). When soil moisture drops below a threshold value cracks begin to develop and expand, which might enhance infiltration due to preferential flow (Bronswijk, 1988;Wells et al, 2003;Vogel et al, 2005a, b). Likewise, if the soil again wets up above a certain threshold value, the cracks begin to shrink and eventually close, and the local infiltration capacity is then substantially reduced.…”

A review of the impact of climate change on future nitrate concentrations in groundwater of the UK

“…Several aspects of the infiltration process in cracking soils have proven to be difficult to measure; seal/crust formation and properties, crack network patterns, preferential flow zones and contributions, and soil moisture determinations within the profile (Wells et al, 2003). For many soils, the physical changes that take place (such as swelling, sealing, shrinkage, and cracking) during and after rain following dry periods greatly affect the movement of water in the soil as the cracks develop deeper and transmit water to lower depths within the profile.…”

“…In addition to swelling and cracking, clay soils form a surface seal, which also greatly affects infiltration (Wells et al, 2003). Surface sealing occurs due to the impact of raindrops on the surface of the soil, causing compaction, and settling of fine-grained detached material on the surface of the soil, effectively clogging the micropores.…”

On the importance of hysteresis and heterogeneity in the numerical simulation of unsaturated flow

“…Deinert et al (2004) presented a method for using real-time neutron radiography to measure rapidly changing moisture profiles in porous media. In an interesting study, Wells et al (2003) used needle penetrometer to measure the depth of the wetting front along a single transect of the soil, immediately after each rainstorm. Wet sand transmits more light than dry sand.…”