Meta‐analysis of field‐saturated hydraulic conductivity recovery following wildland fire: Applications for hydrologic model parameterization and resilience assessment

Abstract

Hydrologic recovery after wildfire is critical for restoring the ecosystem services of protecting of human lives and infrastructure from hazards and delivering water supply of sufficient quality and quantity. Recovery of soil‐hydraulic properties, such as field‐saturated hydraulic conductivity (Kfs), is a key factor for assessing the duration of watershed‐scale flash flood and debris flow risks after wildfire. Despite the crucial role of Kfs in parameterizing numerical hydrologic models to predict the magnitude of postwildfire run‐off and erosion, existing quantitative relations to predict Kfs recovery with time since wildfire are lacking. Here, we conduct meta‐analyses of 5 datasets from the literature that measure or estimate Kfs with time since wildfire for longer than 3‐year duration. The meta‐analyses focus on fitting 2 quantitative relations (linear and non‐linear logistic) to explain trends in Kfs temporal recovery. The 2 relations adequately described temporal recovery except for 1 site where macropore flow dominated infiltration and Kfs recovery. This work also suggests that Kfs can have low hydrologic resistance (large postfire changes), and moderate to high hydrologic stability (recovery time relative to disturbance recurrence interval) and resilience (recovery of hydrologic function and provision of ecosystem services). Future Kfs relations could more explicitly incorporate processes such as soil‐water repellency, ground cover and soil structure regeneration, macropore recovery, and vegetation regrowth.

Stormflow threshold behaviour in a subtropical mountainous headwater catchment during forest recovery period

“…Therefore, the role of vegetation recovery on ecohydrological processes, such as interception, transpiration, floor evaporation, topsoil and deep soil moisture, should help provide a deeper understanding of the runoff threshold responses in this catchment. Apart from vegetation, disturbances such as forest fires can also alter soil surface roughness (Stoof et al, ), soil sealing (Larsen et al, ), soil‐water repellency and retention (Mataix‐Solera et al, ; Moody, Kinner, & Ubeda, ), macropore flow (Nyman, Sheridan, & Lane, ) and soil infiltration rate (Martin & Moody, ), possibly inducing changes in runoff generation mechanisms (Ebel & Martin, ). The concept of generation and rise thresholds may aid understanding to those post‐disturbance runoff characterizations.…”

Effect of soil water‐repellent layer depth on post‐wildfire hydrological processes

“…Wildfires can affect various hydrological processes, such as preventing soil infiltration (Ebel & Moody, ), increasing or reducing surface runoff (Ebel, Moody, & Martin, ; Granged, Jordán, Zavala, & Bárcenas, ), and enhancing subsoil moisture storage due to reductions in transpiration (Helvey, ; Rye & Smettem, ). Wildfire can likewise modify soil hydrologic properties such as wettability (Doerr et al, ), hydraulic conductivity (Ebel & Martin, ), and pore size distribution (Woods & Balfour, ). Fire‐induced alterations in hydrological processes can negatively impact quantity and quality of water supply, thereby increasing the risk to communities that live in or near forests (Certini, ; Chapin et al, ; Ice, Neary, & Adams, ).…”

“…Wildfire can likewise modify soil hydrologic properties such as wettability (Doerr et al, 2006), hydraulic conductivity (Ebel & Martin, 2017), and pore size distribution (Woods & Balfour, 2008). Fireinduced alterations in hydrological processes can negatively impact quantity and quality of water supply, thereby increasing the risk to communities that live in or near forests (Certini, 2005;Chapin et al, 2008;Ice, Neary, & Adams, 2004).…”

Impacts of successive wildfire on soil hydraulic properties: Implications for debris flow hazards and system resilience

“…This study does not address the underlying reasons for differences in soil hydraulic properties among the different burn areas, but we hypothesize that these differences are at least partly due to variations in organic matter at the surface and the top layers of the soil. It may take more than twenty years for soil organic matter to return to pre‐wildfire levels (Tessler et al, ; Ebel and Martin, ). Combustion of soil organic matter plays a role in the destruction of soil aggregates (Mataix‐Solera et al, ) and the formation of wildfire‐enhanced soil water repellency (DeBano et al, ).…”

“…When assessing the response of a system to repeated perturbations, such as wildfire, it can be helpful to cast the problem in terms of system resilience (Brunsden and Thornes, ; Ebel and Mirus, ; Ebel and Martin, ). One measure of the resilience of a system to a perturbation is the ratio of the recovery timescale relative to the recurrence interval of the disturbance (Brunsden and Thornes, ).…”