State dam safety programs are responsible for regulating 95% of the nation’s dams. The National Dam Safety Act establishes appropriations for assisting states in their development of their programs to meet the minimum eligibility requirements for federal assistance grants, and training for state dam inspectors. The model for state dam safety programs recommends that dams be inspected at least every five years.
Alabama is the only state in the U.S. that does not have a dam safety and inspection program in place and therefore is ineligible for federal dam assistance. The Alabama Dam Safety and Security Initiative has been in development for a number of years. In its most recent effort, Representative Randy Wood filed H.B. 454: Alabama Dam Inventory and Classification Act in February 2008, but the measure failed to pass. Without this legislation, no resources (i.e., construction guidelines, dam inspectors, or funding assistance) are available to dam owners in Alabama. For program status updates, contact the Office of Water Resources of the Alabama Department of Economic and Community Affairs.
Even if legislation is passed, the outlook for financial assistance is grim. Over 56% of the 79,000 dams listed in the National Inventory of Dams are privately owned and federal funding for rehabilitation of non-public dams is only provided in rare cases. As of 2003, only nine states were offering limited financial assistance to private dam owners. Waterfront property owners should recognize that some maintenance work and/or repairs to Emerald Lake's dam will inevitably be necessary in the future. Now is the time to plan ahead by setting aside money in anticipation of those costs.
Trees create a host of issues that could ultimately affect a dam’s long-term integrity. Roots loosen compacted soil along their paths, and uprooted trees and rotting stumps create large voids in the embankment. Left unmanaged, seepage paths can develop in these areas and potentially lead to subsidence or erosion through the embankment’s inner core. Because of these risks, modern dam safety guidelines recommend keeping embankments clear of all woody vegetation.
Despite these safety guidelines, tree growth on embankments is quite common, especially on older dams. The Federal Emergency Management Agency (FEMA) estimates that more than half of the nation’s approximately 78,000 state-regulated dams have excessive tree growth. The occurrence of trees on unregulated dams is undoubtedly much higher.
Removing well-established trees from an older dam can be a risky endeavor. For trees over 6 inches in diameter, the stump and rootball must be removed and the voids backfilled with well-compacted soil. Installation of drains, construction of toe slopes, and even major reconstruction of the embankment may also be necessary. Large tree removal should only be performed by an experienced contractor under the guidance of a dam engineer.