Gully Erosion Minimization on Reclaimed Surface Mines Using SSAST Computer Model

Abstract

The Stable Slope and Sediment Transport (SSAST) model, an event‐based computer model, uses postmine hydrology and median overburden grain size of a reclaimed surface mine to calculate a stable slope for the longitudinal channel profile. Peak discharge, which drives postmine erosion, is calculated from a 10‐year, 24‐h storm using the Soil Conservation Service curve‐number method and curve numbers (CNs) calibrated for Pennsylvania surface mines. Reclaimed mine sites may be represented by either a rectangle or triangle that most closely fits the site shape and has the same drainage area and length. Sediment‐transport and slope‐stability algorithms use a modified Bagnold's equation with a correction factor dependent on particle shape. SSAST was calibrated and verified using data from three reclaimed Pennsylvania surface mines. Analyses indicate that SSAST can predict stable longitudinal channel profiles for reclamation of surface mines in the humid, temperate Northeastern United States. Disequilibrium among slope form, surface hydrology, and erosional process on reclaimed surface coal mines can cause gully erosion and sediment loads that are significantly elevated above natural values.