Current through September 24, 2024
(1) Stability. All
dams shall be stable. There shall not be excessive cracks, sloughing, seepage
or other signs of instability or deterioration. In cases where the stability of
the dam is questionable, it shall be the responsibility of the owner to either
demonstrate to the Commissioner that the dam is stable or drain the reservoir
and remedy the unstable condition prior to refilling the reservoir.
(2) Slope Protection
(a) Earth embankments shall be protected from
surface erosion by appropriate vegetation or some other type protective surface
such as riprap or paving and shall be maintained. Examples of appropriate
vegetation include, but are not limited to, Bermuda grass and fescue. All
inappropriate vegetation such as honeysuckle, briers, bushes, and trees shall
be removed from the dam. Some trees may be allowed to remain on a dam if the
Commissioner concurs with a justification from a qualified engineer for doing
so. Such justification must satisfy the Commissioner that the number, size,
location, root characteristics, etc., of such trees will not adversely affect
the dam's structural integrity and safety nor impede inspection.
(b) The root mass of all trees larger than
four (4) inches in diameter as measured at two feet above ground level shall be
grubbed out and the hole backfilled with suitable fill material properly
compacted. Smaller trees may either be cut at ground level or be removed as
specified above. The Commissioner may require an engineer to oversee the tree
removal.
(3) Emergency
Spillway.
(a) All dams shall have an emergency
spillway system with capacity to pass a flow resulting from a 6 hour design
storm indicated in subparagraph (b) of this paragraph for a hazard
classification appropriate for the dam. However, if the applicant's engineer
provides calculations, designs, and plans to show that the design flow can be
stored, passed through, or passed over the dam without failure occurring, or if
he can successfully demonstrate to the Commissioner by engineering analysis
that the dam is a safe structure and can certify that the dam is sufficient to
protect against probable loss of human life downstream, said dam design may be
approved by the Commissioner.
(b)
Minimum Freeboard Design Storms.
| Hazard Potential
Category | Size | Freeboard Design Storm (6 Hours) |
| Category 3 (Low) | Small Intermediate Large | 100 year
1/3 PMP 1/2 PMP |
| Category 2 (Significant) | Small
Intermediate Large | 1/3 PMP 1/2 PMP PMP |
| Category 1
(High) | Small Intermediate Large | 1/2 PMP PMP PMP |
(c) No dam which
is modified after original construction to increase its design storm to a 1/2
PMP or greater shall be required to pass a larger design storm unless the dam
itself is enlarged or its normal or maximum storage volume is
increased.
(4) Concrete
and Masonry Dams. Concrete and/or masonry dams shall be structurally sound and
shall have joints free of trees and other vegetation and shall show no signs of
significant structural deterioration such as excessive cracks, spallation,
efflorescence and exposed reinforcing steel.
Authority:
T.C.A. §§
69-11-101 et seq., and 4-5-201 et
seq.
