INFILTRATION CAPACITY OF DISTURBED SOILS: TEMPORAL CHANGE AND LITHOLOGIC CONTROL¹

Abstract

The hydrologic character and response of disturbed land is controlled, to a large degree, by soil infiltration characteristics. Reconstructed soils on surface mines (minesoils) of different age (1 to 4 years old) are used to investigate infiltration rates on disturbed landscapes. The data consist of soil/surface properties and runoff volumes fit to the Horton infiltration equation. Infiltration rates on newly reclaimed minesoils are an order of magnitude lower than adjacent, undisturbed soil. Few significant correlations exist between soil/surface properties and infiltration parameters for newly reclaimed soils. However, the correlation between infiltration and minesoil characteristics increases with soil age. Multiple regressions are used to explore relationships between infiltration parameters and soil/surface properties for each soil age. Regression models of 30‐min infiltration volume and the steady‐state rate consistently include the percent silt and clay, slope, bulk density, and vegetation. Mean infiltration volumes at different mines are equal in the first year following reclamation, but become significantly different with surface age. The magnitude of the increase is controlled by the soil texture, vegetation, slope, and bulk density. Soil characteristics are determined ultimately by the overburden lithology and its effect on mineralogy and grain size during physical redistribution of soil particles and initial weathering.

Mountaintop Removal Mining and Catchment Hydrology

“…Infiltration rates of minesoil can be an order of magnitude lower than undisturbed forest soils [54,57,65] that cause the initiation of infiltration excess overland flow which dominates storm runoff in mined areas [54,57]. The dominance of surface pathways in runoff generation in mined catchments is further evidenced by the increase in total suspended solids downstream of mining activities [87] that originate from the mine surface during the period immediately following reclamation [88].…”

“…However, Ritter and Gardner [57] observed variability in the infiltration rate of mine soils through time; some minesoils maintain low infiltration rates with minimal recovery, while other minesoils return to near pre-mining rates in as little as four years. Jorgensen and Gardner [54] attribute this variability to overburden lithology which ultimately controls the mineralogy and grain size during the redistribution of soils onto the mine surface and initial weathering. Surprisingly, there is little observed change in bulk density of shallow minesoil [54,89,90].…”

“…Jorgensen and Gardner [54] attribute this variability to overburden lithology which ultimately controls the mineralogy and grain size during the redistribution of soils onto the mine surface and initial weathering. Surprisingly, there is little observed change in bulk density of shallow minesoil [54,89,90]. This dissonance is explained by Guebert and Gardner [62], who show the increase in infiltration rate is due to the development of an extensive macropore structure.…”

“…Excessive surface compaction limits root penetration and growth [78,85] and lowers the available water holding capacity [82,86]. While the conditions described above are nearly ubiquitous for reclaimed surface mines in the region, variation in soil structure and properties result from different machinery and techniques used for reclamation [79,85] as well as the pre-mining overburden lithology [54].…”

Hydrologic Characterization of Multiple Seam Underground and Surface Mining in Northern Appalachia

“…Some earlier studies of the impacts of surface mining and reclamation indicate that precipitation infiltration rates are reduced from pre-mining conditions due to loss of soil structure, soil compaction and lack of vegetative cover (Jorgensen and Gardner, 1987).…”