Jefferson County - East-West Gateway Coordinating Council

A Regional Overview All-Hazard Mitigation Plan 105
Early in this century, as many dams failed due to lack of proper engineering and
maintenance, it was recognized that some form of regulation was needed. One of the
earliest state programs was enacted in California in the 1920s. Federal agencies, such as
the Corps of Engineers and the Department of Interior, Bureau of Reclamation built many
dams during the early part of the twentieth century and established safety standards
during this time. Slowly, other states began regulatory programs. But it was not until the
string of significant dam failures in the 1970s that awareness was raised to a new level
among the states and the federal government.
In Missouri, the first state legislation aimed at regulating dams was passed in 1889 and
was called the Dam Mills and Electric Power Law. The law was concerned only with
damaged caused by construction and lake formation. It did not address the engineering
aspects of design or downstream safety of dams.
In 1972, Congress passed the National Dam Safety Act (P.L. 92-367) that called for an
inventory of dams in the U.S. and one time inspection of dams that would result in loss of
life from a failure. In 1986, Congress enacted the Water Resources Development Act (P.L.
99-662). Title XII-Dam Safety authorized the U.S. Army Corps of Engineers (USACE) to
maintain and periodically update the inventory of dams. In 1988 funds were appropriated
for this effort. FEMA and USACE developed a Memorandum of Agreement where FEMA
assumed responsibility for maintaining and updating the inventory using the funds
authorized. The Water Resources Development Act of 1996 (P.L. 104-303) Section 215 reauthorized
periodic update of the National Inventory of Dams (NID) by USACE and
continued a funding mechanism. For the 1998 update, the USACE resumed the lead
responsibility and worked with FEMA and other agencies. There are about 77,000 dams in
the inventory.
Federal law and the Association of Dam Safety Officials (ASDSO) Model State Dam Safety
program define a dam as “any artificial barrier, including appurtenant works, which
impounds or diverts water and which 1.) is 25 feet or more in height from the natural bed
of the stream or watercourse measured at the downstream toe of the barrier, or from the
lowest elevation of the outside limit of the barrier, if it is not across a stream channel or
watercourse to the maximum water storage elevation; or 2.) has an impounding capacity
at the maximum water storage elevation of fifty acre-feet or more.
This Act does not apply to any such barrier which is not in excess of six feet in height,
regardless of storage capacity, or which has a storage capacity at a maximum water
storage elevation not in excess of fifteen acre-feet, regardless of height (P.L. 92-367; Dam
Safety Act of 1972) unless such barrier, due to its location or other physical characteristic,
is likely to pose a significant threat to human life or property in the event of its failure.”
(P.L. 99-662, Water Resources Development Act of 1986).
Criteria for dams in the NID are as follows:
1). All high hazard potential classification dams