Development of a Methodology for Estimating Embankment Damage Due to Flood Overtopping

DTFH61-82-C-00104The objectives of this study are to conduct laboratory tests and develop a methodology to quantitatively determine embankment damage and assess protective measures. During the study, available literature and field data were collected. The embankments used 4n this study are 6 ft (1.8 m) high, 10 to 22 ft (3.0 to 6.7 m) in crest width, and 3 ft (0.9 m) in length, with slope varying from 2:1 to 3:1. The embankment surfaces include both with and without protective measures (pavement, grass, mattresses, Geoweb, soil cement, Enkamat, and others). The flood overtopping depths ranging from 0.5 to 4 ft (0.15 to 1.22 m), discharges ranging from 1 to 25 cfs/ft (0.1 to 2.32 cms/m) and tailwater conditions ranging from 10 percent water-surface drop to free fall. A computer model was developed to determine hydraulics of overtopping flow and associated erosion damage. This model was verified using field data and laboratory test results, and was utilized to generate charts for estimating embankment damage

Minimizing Embankment Damage During Overtopping Flow

DTFH61-85-C-00131The hydraulic and erosional characteristics of overtopping flow are examined. Methods of protecting earth embankments of dams, levees, and roadways from damage during overtopping flow are investigated. Nineteen full-scale tests of bare earth embankments (unprotected) were conducted to derive baseline erosion rate relationships. Thirty-eight full-scale hydraulic tests examined the performance of selected commercially available embankment protection systems under various hydraulic conditions. These included vegetation, geotextiles, chemicals, cements, concrete blocks, gabions, and riprap. Failure modes and hydraulic stresses at the failure threshold were determined and compared to results from other investigators. Design and installation considerations are presented which address observed failure modes