The OWRB coordinates the Oklahoma Dam Safety Program to ensure the safety of more than 4,600 dams in the state. We are committed to protecting Oklahomans from harm and liability potentially associated with dams.
Dam Safety Program
Woody Vegetation: The Root of All Evil on Your Dam
WHILE TREES AND BRUSH MAY BE AESTHETICALLY PLEASING AND PROVIDE OXYGEN AND COOLING SHADE, THE PROXIMITY OF GROWTH OF VEGETATION TO A DAM CAN CAUSE VERY REAL PROBLEMS
Twenty-nine U.S. states document vegetation as the cause of dam failures or unsafe dam operations.. Erosion, seepage and piping occur when trees, shrubs and dense ground cover are allowed to grow on embankment surfaces or in vegetated earthen spillways.
Extensive root systems can provide seepage paths. Trees that blow down or fall over can leave large holes in embankment surface that will weaken the embankment and lead to increased erosion. Brush can hinder grass cover growth on the slope of the dam as well as camouflage animal burrows and obscure the sight of potential problems during dam inspections. Native grasses and turf grasses, such as Bermuda and Fescue, should be planted on the dam embankments and mowed at least twice a year.
Depending on the size and regional cost a rational estimate for annual mowing maintenance equals about $100.00 per acre compared to about $2500.00 per acre for removal of trees and brush. An example of a recommended guideline for tree removal from the Dam Crest is: Cut trees having stump diameters of twelve inches or less flush with the ground and treat the stump with a waterproof sealant to delay stump decay. Completely remove trees having stump diameters of twelve inches or greater, and backfill root ball cavity with properly compacted backfill soil. The Oklahoma Water Resources Board (OWRB) published guidance documents to aid in the control of woody vegetation. These documents and others pertaining to dam safety and maintenance can be found on the OWRB website at: www.owrb.ok.gov/hazard It is important to schedule routine dam inspections with a licensed engineer to address issues early on.
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Page last updated: May 10, 2013