Submitted to: Journal of the American Water Resources Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/1998
Publication Date: N/A
Interpretive Summary: Government and commercial waste repositories require environmentally safe methods of disposal of low-level radioactive waste. These waste materials are typically buried in shallow trenches where they must remain isolated from the biosphere for 300 to 500 years, until the radiation has decayed to safe levels. Two water related problems can reduce the effectiveness and life expectancy of earthen trench covers in semi-arid regions: surface erosion caused by rainfall and snowmelt runoff, and infiltration of water into the trench resulting in possible leaching of materials out of the site. This study compared the runoff and erosion response of artificial waste burial covers planted with two different grass species typically used at Idaho National Engineering and Environmental Laboratory (INEEL). Simulated rainfall was applied several times over the course of three years to plots planted with crested wheatgrass (a bunch grass) and to plots planted with streambank wheatgrass (a sod grass). Average total runoff and average total soil loss from simulated rainfall was significantly greater on the streambank wheatgrass plots than the crested wheatgrass plots. This study indicates that crested wheatgrass appears to be better suited for revegetation of waste burial covers at the INEEL than streambank wheatgrass due to its much lower erosion rate and only slightly higher infiltration rate.
Technical Abstract: Control of runoff (reducing infiltration) and erosion at shallow land burials is necessary in order to assure environmentally safe disposal of low-level radioactive-waste and other waste products. This study evaluated the runoff and erosion response of two perennial grass species on simulated waste burial covers at Idaho National Engineering and Environmental Laboratory (INEEL). Rainfall simulations were applied to three plots covered by crested wheatgrass [Agropyron desertorum (Fischer ex Link) Shultes], three plots covered by streambank wheatgrass [Elymus lanceolatus (Scribner and Smith) Gould spp. lanceolatus], and one bare plot. Average total runoff for rainfall simulations in 1987, 1989, and 1990 was 42 percent greater on streambank wheatgrass plots than on crested wheatgrass plots. Average total soil loss for rainfall simulations in 1987 and 1990 was 105 percent greater on streambank wheatgrass plots than on crested wheatgrass plots. Total runoff and soil loss from natural rainfall and snowmelt events during 1987 were 25 and 105 percent greater, respectively, on streambank wheatgrass plots than on crested wheatgrass plots. Thus, crested wheatgrass appears to be better suited in revegetation of waste burial covers at INEEL than streambank wheatgrass due to its much lower erosion rate and only slightly higher infiltration rate (lower runoff rate).