Current through Register Vol. 30, No. 38, September 20, 2024
The owner and engineer are responsible for complete and
adequate design of a dam and for including in the application all aspects of
the design pertaining to the safety of the dam.
1. Construction Drawing Requirements. The
construction drawings required by
R12-15-1208(5),
R12-15-1209(E)(1),
and R12-15-1210(A)(6) shall include the following:
a. The seal and signature of the responsible
engineer in accordance with A.A.C.
R4-30-304.
b. One or more topographic maps of the dam,
spillway, outlet works, and reservoir on a scale large enough to accurately
locate the dam and appurtenances, indicate cut and fill lines, and show the
property lines and ownership status of the land. Contour intervals shall be
compatible with the height and size of the dam and its appurtenances and shall
show design and construction details.
c. A reservoir area and capacity curve that
reflect area in acres and capacity in acre-feet in relation to depth of water
and elevation in the reservoir. The construction drawings shall show the
spillway invert and top of dam elevations. The construction drawings shall also
show the reservoir volume and space functional allocations. The construction
drawings may include alternate scales as required for the owner's
use.
d. Spillway and outlet works
rating curves and tables at a scale or scales that allow determination of
discharge rate in cubic feet per second at both low and high flows as measured
by depth of water passing over the spillway control section.
e. A location map showing the dam footprint
and all exploration drill holes, test pits, trenches, adits, borrow areas, and
bench marks with elevations, reference points, and permanent ties. This map
shall use the same vertical and horizontal control as the topographic
map.
f. Geologic information
including 1 or more geologic maps, profile along the centerline, and other
pertinent cross sections of the dam site, spillway or spillways, and
appurtenant structures, aggregate and material sources, and reservoir area at 1
or more scales compatible with the site and geologic complexity, showing logs
of exploration drill holes, test pits, trenches, and adits.
g. One or more plans of the dam to delineate
design and construction details.
h.
Foundation profile along the dam centerline at a true scale where the vertical
scale is equal to the horizontal scale, showing the existing ground and
proposed finished grade at cut and fill elevations, including anticipated
geologic formations. The foundation profile shall include any proposed grout
and drain holes.
i. Profile and a
sufficient number of cross sections of the dam to delineate design and
construction details. The drawings shall illustrate and show dimensions of
camber, details of the top, core zone, interior filters and drains, and other
zone details. The profile of the dam may be drawn to different horizontal and
vertical scales if required for detail. A maximum section of the dam shall be
drawn to a true scale, where the vertical scale is equal to the horizontal
scale. The outlet conduit may be shown on the maximum section if this is
typical of the proposed construction.
j. One or more dam foundation plans showing
excavation grades and cut slopes with any proposed foundation preparation,
grout and drain holes, and foundation dewatering requirements.
k. Plan, profile, and details of the outlet
works, including the intake structure, the gate system, conduit, trashrack,
conduit filter diaphragm, conduit concrete encasement, and the downstream
outlet structure. The drawings shall include all connection and structural
design details.
l. Plan, profile,
control section, and cross sections of the spillway, including details of any
foundation preparation, grouting, or concrete work that is planned. A complex
control structure, a concrete chute, or an energy dissipating device for a
terminal structure shall include both hydraulic and structural design
details.
m. Hydrologic data,
drainage area and flood routing, and diversion criteria.
2. Construction Specification Requirements.
The construction specifications required by
R12-15-1208(6)
and R12-15-1210(A)(7) shall include the following:
a. The seal and signature of the responsible
engineer in accordance with A.A.C.
R4-30-304.
b. The statement that the construction
drawings and specifications shall not be materially changed without the prior
written approval of the Director.
c. A detailed description of the work to be
performed and a statement of the requirements for the various types of
materials and installation techniques that will enter into the permanent
construction.
d. The statement that
construction shall not be considered complete until the Director has approved
the construction in writing.
e. The
statement that the owner's engineer shall control the quality of
construction.
f. The following
construction information:
i. All earth and
rock material descriptions, placement criteria, and construction requirements
for all elements of the dam and related structures.
ii. All concrete, grout, and shotcrete
material and mix descriptions, placement and consolidation criteria,
temperature controls, and construction requirements for all elements of the dam
and related structures.
iii.
Material criteria and material testing, cleaning, and treatment. If foundation
or curtain grouting is required, the specifications shall describe the type of
grout, grouting method, special equipment necessary, recording during grouting,
and foundation monitoring to avoid disturbance from grouting.
iv. All materials testing that will be
performed by the contractor for pre-qualification of materials, including
special performance testing, such as water pressure tests in conduits. The
Director shall accept materials that are pre-tested successfully and
constructed in-place in accordance with specifications.
v. A plan for control or diversion of surface
water during construction. The design engineer may determine frequency of storm
runoff to be controlled during construction, commensurate with the risk of
economic loss during construction.
vi. Criteria for blast monitoring and
acceptable blast vibration levels, including particle velocities for the dam
and other critical appurtenances. Monitoring equipment and monitoring locations
shall be specified.
vii.
Instrumentation material descriptions, placement criteria, and construction
requirements and a statement that instrumentation shall be installed by
experienced speciality subcontractors.
3. Engineering Design Report Requirements.
The engineering design report required by
R12-15-1208(7)
and
R12-15-1210(A)(8)
shall include the following:
a. The seal and signature of the responsible
engineer in accordance with A.A.C. R4-30-304.
b. The classification under
R12-15-1206
of the proposed dam, or for the proposed enlargement of an existing dam or
reservoir.
c. Hydrologic
considerations, including calculations and a summary table of data used in
determining the required emergency spillway capacity and freeboard, and design
of any diversion or detention structures. The design report shall include input
and output listings on both hard copy and computer diskette.
d. Hydraulic characteristics, engineering
data, and calculations used in determining the capacities of the outlet works
and emergency spillway. The design report shall include input and output
listings on both hard copy and computer diskette.
e. Geotechnical investigation and testing of
the dam site and reservoir basin. Results and analysis of subsurface
investigations, including logs of test borings and geologic cross
sections.
f. Guidelines and
criteria for blasting to be used by the contractor in preparing the blasting
plan.
g. Details of the plan for
control or diversion of surface water during construction.
h. Details of the dewatering plan for
subsurface water during construction.
i. Testing results of earth and rock
materials, including the location of test pits and the logs of these
pits.
j. Discussion and design of
the foundation blanket grouting, grout curtain, and grout cap based on
foundation stability and seepage considerations.
k. Calculations and basic assumptions on
loads and limiting stresses for reinforced concrete design. The design report
shall include input and output listings on both hard copy and computer
diskette.
l. A discussion and
stability analysis of the dam including appropriate seismic loading, safety
factors, and embankment zone strength characteristics. Analyses shall include
both short-term and long-term loading on upstream and downstream slopes. The
design report shall include input and output listings on both hard copy and
computer diskette.
m. A discussion
of seismicity of the project area and activity of faults in the vicinity. The
design report shall use both deterministic and statistical methods and identify
the appropriate seismic coefficient for use in analyses.
n. Discussion and design of the cutoff trench
based on seepage and other considerations.
o. Permeability characteristics of foundation
and dam embankment materials, including calculations for seepage quantities
through the dam, the foundation, and anticipated in the internal drain system.
The design report shall include input and output listings on both hard copy and
computer diskette. The design report shall include copies of any flow nets
used.
p. Discussion and design of
internal drainage based on seepage quantity calculations. The design report
shall include instrumentation necessary to monitor the drainage system and
filter design calculations for protection against piping of foundation and
embankment.
q. Erosion protection
against waves and rainfall runoff for both the upstream and downstream slopes,
as appropriate.
r. Discussion and
design of foundation treatment to compensate for geological weakness in the dam
foundation and abutment areas and in the spillway foundation area.
s. Post-construction vertical and horizontal
movement systems.
t. Discussion of
foundation conditions including the potential for subsidence, fissures,
dispersive soils, collapsible soils, and sink holes.