Tracking, measuring and predicting the path of water in soil is of environmental importance. Such data can assist with the managing of water resources, especially in territories where water is scarce, and helping to manage flood defences where flooding from rivers poses a risk to local communities.
With areas at risk of drought, for example, understanding water flow helps to guide how often aquifers need to re-charged. In areas at risk from soil erosion, better planning can be undertaken to protect communities. A further use for such studies is with agriculture, in terms of assessing the flow of water and nutrients to plants.
Soil itself is a multi-part and complex material. It is made up of sand, silt, and clay particles, together with waste matter and microorganisms.
The assessment of water through soil is based on hydraulic conductivity (a property of vascular plants, soils and rocks), with water droplets shifting through macropores (essentially empty spaces within the soil.) The size and shape of pore effects the water flow rate, where the larger the pore then the faster the water flows. The flow of water is not simply an issue of size, for the geometric shape also affects water flow. Moreover, soil will behave differently if it is permeated by different fluids, for example water or hydrocarbons (like oil).
To gain more information, researchers have developed a technique called a multistripe laser triangulation (MLT) scanner. This is, as described in Laboratory Manager magazine, based on laser technology. To verify the accuracy of the laser, blue dye was used to saturated samples of soil and the pattern of the dye verified against readings from the laser device.
The study of soil hydrology was carried out by University of Kansas scientists. The findings are published in the Vadose Zone Journal. The research paper is headed “Relating Quantitative Soil Structure Metrics to Saturated Hydraulic Conductivity.”
