Greener Journal of Physical Sciences Vol. 3 (5), pp. 177-186, August 2013.
ISSN: 2276-7851 © 2011 Greener Journals
Manuscript Number: 052813642
Environmental Impacts of Earth Dam Failures and Spillway Malfunctions
Great Zimbabwe University, P.O. Box 1235, Masvingo, Zimbabwe, Africa.
Email: elijahnyoni @ yahoo.com,
Cell No: +263775087075, Fax: +263 (39) 252100
This study was carried out in selected districts of
Mashonaland, East and Central provinces of Zimbabwe in 2011
to determine the environmental impacts of earth dam failures
and spillway malfunctions with regards to soil erosion. A
total of 14 earth dams were investigated. Eight dams
contributed to soil erosion whilst six did not. Of the eight
dams, half of them had breached. The remainder had not
breached but had eroded the spillway channel. Only one dam
breached without causing soil erosion. The properly
constructed dams had contributions to degradation due to
erosion ranging from 0.1% to 2.8%. Dam code 3 had the
highest contribution to degradation due to soil erosion of
42%. The paper concluded that there is critical loss of soil
when a dam fails or when a spillway malfunctions. Concerning
spillways, it was shown that when the spillway channel is
not properly designed, a lot of soil lose occurs within its
Keywords: Breached; Spillway; Overtopping; Erosion; Subcritical flow; Supercritical flow; Classification.