Linking hydraulic properties of fire-affected soils to infiltration and water repellency

Heat from wildfires can produce a two-layer system composed of extremely dry soil covered by a layer of ash, which when subjected to rainfall, may produce extreme floods. To understand the soil physics controlling runoff for these initial conditions, we used a small, portable disk infiltrometer to measure two hydraulic properties: (1) near-saturated hydraulic conductivity, K_f and (2) sorptivity, S(θ_i), as a function of initial soil moisture content, θ_i, ranging from extremely dry conditions (θ_i