Current through Register Vol. 49, No. 9, September, 2024
TITLE VII
RULES GOVERNING DESIGN AND
OPERATION OF DAMS
[As Restated October/ 1993]
SUBTITLE
I.
GENERAL PROVISIONS
Section 701.1.
PURPOSE.
A. Provide for the
comprehensive regulation and supervision of dams for the protection of the
health, safety, welfare and property of the citizens of Arkansas.
B. Assure proper planning, design,
construction, maintenance, monitoring and supervision of dams, including such
preventive measures as are necessary to provide an adequate margin of
safety.
Section 701.2.
AUTHORITY. Rules governing design and operation of
dams within the State of Arkansas are promulgated under authority of Subchapter
2 of Chapter
22 of Title 15 of the Arkansas Code of
1987.
Section 701.3.
SCOPE OF REGULATIONS. All dams within the State of Arkansas,
except those owned by the United States Government or those exempted by Section
701.4,
must have a valid construction and operation permit issued under the provisions
of this title.
Section 701.4.
EXEMPTIONS. Dams meeting either of the following
criteria are not subject to rules contained in this title, unless Section
701.5
of this title is successfully invoked.
A. Dams
with height less than 25 feet.
B.
Dams with normal storage less than 50 acre-feet.
C. Dams with crest elevations below the
ordinary high water mark of the stream at that location.
Section 701.5.
PETITION BY
AFFECTED PERSONS. Persons who believe themselves or their property
to be endangered by failure of a dam which is below the size requirements
specified in Section
701.4
may file a petition requesting that the Commission require permitting and
compliance with dam safety regulations for that dam.
A.
Commission
Investigation. Upon receipt of such petition, the Executive
Director shall immediately begin an investigation of the petitioner's
allegations.
B.
Public
Hearing. As a part of the Commission's investigation, a Public
Hearing shall be held within the county in which the dam is located. Notice of
the hearing shall be published in a manner consistent with Section
702.8.
C.
Commission Order.
Upon consideration of staff findings and testimony received, the Commission
shall issue an order either approving or denying the petitioner's
request.
Section 701.6.
DUTIES, OBLIGATIONS. AND LIABILITIES OF DAM OWNERS.
Nothing in these rules shall be construed to relieve an owner or operator of a
dam or reservoir of the legal duties, obligations, or liabilities incident to
ownership or operation.
Section
701.7.
NO LIABILITY BY COMMISSION, EMPLOYEES, OR
AGENTS. No action shall be brought against the State or the
Commission or its employees or agents for the recovery of damages caused by the
partial or total failure of any dam or reservoir or through the operation of
any dam or reservoir upon the grounds that the aforementioned parties are
liable by virtue of any of the following:
A.
The approval of the dam or reservoir, or approval of flood-handling plans
during construction;
B. The
issuance or enforcement of orders relative to maintenance and operation of the
dam or reservoir;
C. Inspection,
control and regulation of the dam or reservoir;
D. Measures taken to protect against failure
during an emergency.
Section
701.8.
EXCEPTIONS. The Commission may
grant exceptions to requirements contained within this title. Any variance from
these rules must be supported by written approval of the Commission's Executive
Director setting forth the reason for its granting and the limits placed
thereon.
SUBTITLE II.
PERMITS FOR DAMS
Section 702.1.
CONSTRUCTION
PERMIT. A permit issued by the Commission is required prior to
construction of any dam not exempted under Sections
7 01.3 or 701.4 of this title.
Section 702.2.
OPERATION
PERMIT.
A. Before water is
deliberately impounded by closing drain gates on a newly constructed dam, an
operation permit must be issued by the Commission. An operation permit will be
issued by the Chief Engineer upon completion of final inspection and receipt of
the Certificate of Substantial Compliance by the owner's engineer. (See Section
706.6)
B. An operation permit is required for all
existing dams not exempted under Sections
701.3
or
701.4
of this title.
Section
702.3.
TRANSFER OF PERMIT. Within six (6)
months after change of ownership of a permitted dam, the new owner shall notify
the Commission. The Commission shall issue a dam permit in the name of the new
owner.
Section 702.4.
WATER PLAN COMPLIANCE. Filing of an application to
permit a proposed dam also serves as filing for Water Plan Compliance
Certification as described in Section
602.5
of the Commission's rules. The water plan compliance process may run
concurrently with the dam permit review.
Section
702.5.
APPLICATION. Applicants for dam
permits must provide all applicable information requested on the form supplied
by the Commission.
Section 702.6.
COMMISSION REVIEW. Upon receipt of application for dam
permit, the Commission staff will review data presented to determine compliance
with State law, Commission rules, and accepted engineering practices. If
necessary, the staff may request additional data to insure
compliance.
Section 702.7.
PUBLIC NOTICE. Upon completion of Commission review,
the Executive Director will cause a Public Notice to be published two times,
one week apart. The Public Notice will be placed in a newspaper having general
circulation in the county in Which the - dam is/will be located. Information in
the public notice will include: the owner's name and address, the dam's
location and pertinent physical data describing the dam. In addition, the
Public Notice will request that questions, comments and objections to the dam's
permitting and/or requests for public hearing be forwarded in writing to the
Commission for action within twenty (20) days after the second
publication.
Section 702.8.
PUBLIC HEARING. If requested, the Executive Director
shall cause a Public Hearing to be conducted within the county in which the dam
is /will be located. Said hearing will be for the purpose of describing the
proposed actions and taking testimony regarding the public view of the
proposal. The Executive Director shall cause publication of a public notice
describing the time, place and purpose of the Public Hearing. Copies of the
public notice shall be furnished to the owner(s), complainant (s) and adjacent
landowners (if known). Publication shall be in a newspaper having general
circulation in the county in which the dam is/will be located. Notice shall be
published twice, one week apart.
Section
702.9.
COMMISSION ACTION.
A. If no Public Hearing is requested as a
result of the Public Notice, the Executive Director will either approve or deny
the permit request.
B. If a Public
Hearing is requested as a result of the Public Notice, the Executive Director
will approve or deny the permit request based upon the evidence presented. C.
Prior to issuance of the permit, a Water Plan Compliance Certification must be
obtained as prescribed in Title VI of the Commissions' rules, if
applicable.
SUBTITLE
III.
FEES
Section 703.1.
ESTIMATED
APPLICATION REVIEW FEES. Any application for permitting a proposed
dam after March 24, 1993, shall be accompanied by a check for one percent (1%)
of the estimated construction cost of the dam or $100.00, whichever is greater,
except that no application review fee shall exceed $1000.00.
Section 703.2.
FINAL COST
REPORT. The owner shall provide to the Commission a report of
actual construction costs within forty-five (45) days after completion of
construction.
Section 703.3.
FINAL APPLICATION REVIEW FEES.
A. If the estimated application review fee
exceeds the fee based on actual construction cost, an amount equal to the
difference will be refunded.
B. If
the fee based on construction cost exceeds the estimated application review
fee, an amount equal to the difference will be paid to the
Commission.
Section
703.4.
ANNUAL PERMIT FEE. The annual
permit fee shall be computed as specified in Ark. Code Ann. §
15-22-219, as may
be amended from time to time.
Excerpt from Ark. Code Ann. §
15-22-219:
Any person obtaining a permit under the
provisions of §
15-22-210
shall, In
consideration therefor, pay to the commission a fee equal
to twelve (12¢) per acre-foot of water which the dam involved is designed
to impound, but not less than twenty-five dollars ($25.00), nor more than ten
thousand dollars ($10,000.00) . The permit shall provide that the same fee
shall be paid by that person to the commission each year thereafter during
which the dam is maintained, on or before the anniversary date of the issuance
of the permit.
The volume "the dam involved is designed to impound" is defined
as the billing volume. (See Subtitle XII, GLOSSARY)
SUBTITLE IV.
ENFORCEMENT
Section
704.1.
NOTICE OF NON-EMERGENCY
DEFICIENCY. Upon discovery of a deficiency, which does not
immediately threaten the dam's safety, the Chief Engineer will issue a letter
specifying actions necessary to remedy the problem and requesting a schedule
for implementing the required actions. Based on mutual agreement a consent
order will be issued which will embody the agreed upon actions and
timetable.
Section 704.2.
PUBLIC HEARINGS. In the event remedial measures for
non-emergency deficiencies cannot be accomplished through the means of consent
orders, the Executive Director shall cause a Public Hearing to be conducted to
present the staff's proposed order and accept testimony. The hearing shall be
conducted in the county in which the dam is located. Public notice of the
hearing shall be provided in a manner consistent with Section
702.8
of this title.
Section 704.3.
COMMISSION ORDERS. After review of findings of the
Public Hearing, the Commission may issue orders compelling specified
actions.
Section 704.4.
PENALTIES. Non-compliance with commission rules or
disregard of Commission orders may result in fines of up to $10,000. In
general, penalties will be set by doubling the costs incurred by the
commission.
Section 704.5.
EMERGENCY REMEDIAL ORDERS. Upon discovery of a
condition which renders a dam subject to rapid failure, the Executive Director
may issue an Emergency Remedial Order describing actions which must be taken to
protect life and property. Failure to comply with these orders may result in
penalties under Section
7 04.4.
Section 704.6.
APPEALS. Actions by the Commission may be appealed as
described in Subtitle V of Title I, Rules of Organization and General
Operation of the Arkansas Soil and Water Conservation
Commission.
SUBTITLE
V.
DESIGN CRITERIA
Section 705.1.
GENERAL
STANDARDS. All dams must be designed in accordance with currently
accepted engineering practices. Acceptable guidelines include those published
and recommended by the U. S. Army Corps of Engineers; U. S. Department of
Agriculture, Soil Conservation Service; U. S. Department of Interior, Bureau of
Reclamation; and Federal Energy Regulatory Commission.
Section 705.2.
REGISTERED
PROFESSIONAL ENGINEER. Preparation of all plans and
specifications, and the construction, enlargement, alteration, repair or
removal of dams subject to Commission review shall be under the supervision of
an engineer registered in this state.
Section
705.3.
SIZE CLASSIFICATION CRITERIA. Size
classification is based on the more stringent of two categories, either height
of dam or maximum storage, and shall be in accordance with Table 1 of this
section.
Table 1 SIZE CLASSIFICATION
SIZE |
MAXIMUM STORAGE (ACRE-FEET) |
HEIGHT (FEET) |
Small |
50 to 1000 |
25 to 40 |
Intermediate |
[GREATER-THAN OR EQUAL TO] 1000 |
[GREATER-THAN OR EQUAL TO] 40 |
and [GREATER-THAN] 50,000 |
and [GREATER-THAN] 100 |
Large |
[GREATER-THAN OR EQUAL TO] 50,000 |
[GREATER-THAN OR EQUAL TO] 100 |
Section
705.4.
HAZARD CLASSIFICATION CRITERIA.
All dams will be classified or reclassified as required to assure appropriate
safety considerations. Hazard classification shall be based on the more
stringent of either potential loss of human life or economic loss in accordance
with Table 2 of this section. If doubt exists concerning classification, the
more hazardous category must be selected.
NOTE: The hazard classification does not
indicate the physical condition of a dam.
Table 2 HAZARD CLASSIFICATION
CATEGORY
|
LOSS OF HUMAN LIFE
|
ECONOMIC LOSS |
Low |
No |
Minimal (No significant structures; pastures,
woodland, or largely undeveloped land); less than $100,000. |
Significant |
No |
Appreciable (Significant structures, industrial, or
commercial development, or cropland); $100,000 to $500,000. |
High |
Yes |
Excessive (Extensive public, industrial,
commercial, or agricultural development); over $500,000. |
NOTE; Loss of human life is based upon
presence of habitable structures.
Section
705.5.
SPILLWAY DESIGN FLOOD (SDF) FOR
DAMS. The size and hazard classifications are combined to
determine the hydrologic criteria for dams.
A. The minimum acceptable spillway design
floods (SDFs) for dams are shown in Table 3.
B. The minimum hydrologic criteria may be
reduced if properly prepared dam breach analyses show that dam failure during
the SDF would cause an increase in flood level of one foot or less at, and
downstream of, the first habitable structure or financially significant
development.
Table 3 SPILLWAY DESIGN FLOOD FOR DAMS
HAZARD CLASSIFICATION |
SIZE |
SPILLWAY DESIGN FLOOD |
Low |
Small |
.25 PMF |
|
Intermediate
|
.25 to .50 PMF |
|
Large
|
.50 to .75 PMF |
Significant |
Small |
.25 to .50 PMF |
|
Intermediate
|
.50 to PMF |
|
Large
|
PMF |
High |
Small |
.50 PMF to PMF |
|
Intermediate
|
PMF |
|
Large
|
PMF |
NOTE: Where ranges are given in this
table, the spillway design flood shall be determined by straight line
interpolation, based upon the effective height of dam or maximum storage,
whichever computed SDF is greater.
*SDF shall be extrapolated at the same rate of change as an
intermediate size dam to a maximum of .75 PMF.
Section 705.6.
DOWNSTREAM
RELEASES. Each dam constructed after the effective date of these
regulations shall be equipped with a release port(s) designed to release a flow
of water for instream and downstream riparian uses.
A. Minimum release quantities shall be
sufficient to maintain existing instream and offstream uses and shall be
defined after consideration of the best available low flow
information.
B. Minimum release
ports must be designed to operate without manual
intervention.
Section
705.7.
RESERVOIR DRAIN CONDUIT. All
proposed dams must include a permanent facility for draining the reservoir.
A. Such conduit shall have a minimum diameter
of twelve (12) inches for watershed areas less than one square mile and
eighteen (18) inches for watershed greater than one square mile. Such conduits
must be capable of lowering the surface of the reservoir at a rate not less
than two (2) inches per day (at normal pool) while inflow to the reservoir is
twice the annual average daily flow.
B. Operating equipment for the drain facility
must be accessible from above the maximum design water surface, unless inlet
design is such that the conduit is flowing at capacity at a lower
elevation.
Section 705.8.
STRUCTURAL CRITERIA. As a minimum, the design must
address the following:
A. Slope stability
under all probable loading conditions.
B. Stability against sliding and
overturning.
C. Adequacy of
foundation for imposed loads.
D.
Adequacy of energy dissipating devices at discharge points.
E. Adequacy of channels and conduits for
expected flows.
F. Protection of
embankments and other earth slopes from erosion.
G. Stability against seismic forces for all
"High or Significant Hazard" dams in Seismic Zones 2 and 3. (See Figure
1.)
SUBTITLE
VI.
CONSTRUCTION
REQUIREMENTS
Section
706.1.
PLANS AND SPECIFICATIONS. Written
approval of plans and specifications must be obtained from the Chief Engineer
prior to start of construction.
Section
706.2.
CONSTRUCTION INSPECTIONS. An agent
of the design registered professional engineer must be on site during
construction to ensure that techniques and materials used comply with plans and
specifications.
Section 706.3.
CONSTRUCTION RECORDS. The applicant (or applicant's
engineer) must retain construction records throughout the life of the dam. As a
minimum, the records must include:
A. Daily
log of construction activities.
B.
Record of personnel and equipment on site.
C. Documentation of soil tests such as
standard proctor, in-place density, and moisture.
D. Documentation of concrete cylinder
tests.
E. Copies of all engineering
change orders and field change notes.
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Section
706.4.
EROSION PROTECTION. During
construction, adequate measures must be taken to prevent excessive erosion and
off site sedimentation. Suitable techniques include:, temporary vegetation,
mulching, staked straw bales, filter fences, and chemical stabilization. Other
techniques may be used if approved by the Chief Engineer.
Section 706.5.
FINAL
INSPECTION. Upon substantial completion of construction, the owner
must notify the Commission and schedule a final inspection of the
work.
Section 706.6.
ENGINEER'S CERTIFICATION. Upon completion of
construction, the project engineer shall file with the Commission a certificate
of substantial compliance with approved plans and specifications.
Section 706.7.
RECORD
DRAWINGS. Within sixty (60) days after completion of construction,
the owner, or his engineer, shall submit to the Chief Engineer a complete set
of record drawings of the project for filing as a permanent record with the
Commission.
Section 706.8.
PERMANENT REFERENCE MARKS. Two or more permanent
reference marks shall be established for future use near but not on the dam.
Accurate longitude, latitude and elevation shall be shown on the record
drawings. Elevations shall be referenced to the National Geodetic Vertical
Datum of 1929.
SUBTITLE
VII.
EVALUATIONS OF EXISTING
DAMS
Section 707.1.
TYPES OF EVALUATIONS.
A.
Spillway Design
Flood. Existing dams will be evaluated periodically to determine
if development of downstream areas warrants change in hazard classification and
review of spillway design flood (SDF). Overtopping during the SDF may be
allowed if properly prepared analyses demonstrate that:
(1) overtopping will have a return interval
greater than 25 years; and
(2) the
dam will withstand the projected overtopping without failure.
B.
Structural. A complete evaluation of the structural
integrity may include the following: geotechnical investigation, structural
stability, seismic resistance, horizontal and vertical alignments, structural
concrete reliability, erosion controls, inlet and outlet works, stilling
basins, seepage, and others.
C.
Operation and Maintenance. Evaluation of an existing
structure shall include, but not be limited to: visual inspections and
evaluations of potential problems such as leakage, seepage, cracks, slides,
settlement, spillway blockages, conduit controls and other operational and
maintenance deficiencies which could lead to failure of the dam. There may be
sufficient evidence for a finding that an existing dam is
inadequate.
Section
707.2.
DEFICIENCIES. Dams not meeting
minimum acceptable standards (See Subtitle V and VIII) are deemed inadequate
and therefore subject to necessary action under Subtitle IV.
Section 707.3.
INTERIM
ALTERNATIVES. When the Commission considers the permanent
upgrading or removal of an inadequate dam, the dam owner may request the
Commission to consider interim alternatives including, but not limited to,
temporary repairs, reservoir dewatering, insurance coverage, and downstream
warning/evacuation plans. Consideration shall be given to the time required to
overcome economic, physical and legal restraints to upgrading, the prospect of
permanent repair, current use of the facility, degree of risk, and public
welfare.
Section 707.4.
VARIANCE. Upon request by the owner of an existing
dam which does not meet the minimum acceptable standards stated in Subtitles V
and VIII of this title, the Chief Engineer may authorize a variance from this
criteria. The Chief Engineer's decision shall consider:
(a) consequences of dam failure,
(b) the owner's proposal for reduction of
hazards,
(c) barriers to upgrading
of the structure, and
(d) other
pertinent factors.
SUBTITLE
VIII.
OPERATION AND
MAINTENANCE
Section
708.1.
COMPLIANCE WITH APPROVED
DOCUMENTS. Operation and maintenance must be performed in accord
with documents filed by the owner or owner's engineer in obtaining the dam
permit.
Section 708.2.
EROSION PROTECTION. Maintenance of adequate means to protect
embankments, abutments, crests, and earthen channels from erosion is
required.
Section 708.3.
WOODY VEGETATION PROHIBITED: EMBANKMENT DAMS. Growth
of woody vegetation is not permitted on the spillway, crest, upstream or
downstream embankments, and within twenty (20) feet of the downstream toe or
groin of the dam.
A.
Remediation: Trees with roots likely to extend to the
crest of the dam shall be removed. Trees whose roots are unlikely to extend to
the crest may remain if erosion control vegetation can be maintained and
inspections can be accomplished. Trees larger than six (6) inches in diameter
which are to be removed from embankments, must be removed together with roots
larger than two inches. The resulting voids shall be repaired with compacted
soil similar to the remaining embankment material. Smaller trees and brush, and
those not on embankments may be cut and/or treated with herbicide.
B.
Time for
compliance; New growth must be removed before it shades out
desirable vegetation generally on a two year cycle. Where extensive tree and
brush growth were established prior to adoption of these rules, a compliance
schedule of up to five years may be approved provided that:.
(a) No evidence of significant immediate
hazard is detected;
(b) The
compliance schedule includes a reasonable estimate for costs, and a rational
procedure for accumulating necessary funds;
(c) Vegetation is not so dense that effective
inspections are impossible; and
(d)
Appropriate, annual efforts are scheduled. The long term schedule may be
cancelled if evidence of immediate hazards is discovered in subsequent
inspections.
Section
708.4.
WOODY VEGETATION PROHIBITED; CONCRETE OR
MASONRY DAMS. No grass, vines, brush, trees or other vegetation is
permitted to grow in cracks or joints of concrete or masonry structures.
A.
Remediation:
Vegetation shall be removed by manual, mechanical or chemical means or a
combination thereof. Open cracks or joints shall be repaired by approved
means.
B.
Time for
compliance: In the absence of conditions indicating immediate
hazards, a schedule resulting in complete compliance within six months may be
approved.
Section 708.5.
OPERATION OF GATES AND CONTROLS. All gates, valves and
controls, must be maintained in operational condition. Operation of each such
item must be tested at least annually, and such tests must be documented in the
owner's permanent records* However, tests may be waived by the Chief Engineer
if the design of drainage facilities and/or their condition is such that
reclosing the drain would be impossible until the reservoir was substantially
emptied.
Section 708.6.
REPAIRS AND MODIFICATIONS. Written approval by the
Chief Engineer is required before repairs or modifications to a dam or
appurtenances may be undertaken. Plans and specifications prepared by a
registered professional engineer may be required for major actions.
Section 708.7.
RECORDS. -Documentation of all owner's inspections,
and repairs or modifications to the dam or appurtenances must be retained by
the owner.
SUBTITLE IX.
INSPECTION
Section
709.1.
OWNER INSPECTIONS. At least once
per year and after each major storm event, the owner (or owner's agent) of all
permitted dams must perform a visual inspection of the dam. Results of such
inspections must be summarized on forms supplied by the Commission and mailed
to the Commission office within 10 days of inspection. Commission staff may
provide training or assistance in performing or interpreting inspections. Any
deterioration of the dam or appurtenances must be reported to the Commission,
and remedial measures undertaken after approval by the Chief
Engineer.
Section 709.2.
COMMISSION INSPECTIONS. Commission personnel will
periodically perform inspections of each permitted dam. Commission inspections
are of three types: Maintenance and Operation; Dam Safety Evaluation; and
Emergency. The frequency of inspections and evaluations will vary according to
the hazard rating, size and condition of the dam. Emergency inspections will be
performed when conditions warrant.
Section
709.3.
ACCESS. The owner or owner's
agent must provide Commission personnel access to the dam during reasonable
working hours for Commission inspections. Access during emergency conditions
must be available to Commission personnel.
Section 709.4.
ASSISTANCE BY
OWNER. The owner or owner's agent may be requested to provide
limited assistance to Commission personnel in performing inspections. Requested
assistance may include:
A. Operating gates,
valves, and other controls.
B.
Cutting excessive vegetation in preparation for
inspections.
SUBTITLE
X
EMERGENCY ACTION PLANS
Section 710.1.
EMERGENCY ACTION
PLANS REQUIRED. An emergency action plan (EAP) must be prepared by
the owner for all permitted high hazard dams.
Section 710.2.
APPROVAL OF
EMERGENCY ACTION PLANS REQUIRED. Written approval of the Chief
Engineer must be obtained for all EAPs.
Section
710.3.
CONTENTS OF EMERGENCY ACTION
PLANS. Site conditions will dictate exact contents of specific
EAPs. Guidelines for preparation of EAPs are available from the
Commission.
Section 710.4.
ANNUAL EXERCISES AND DRILLS. Implementation of EAPs
must include at least one table-top exercise per year and one test drill every
three years. The Commission's Chief Engineer must be notified at least one week
in advance of either procedure.
SUBTITLE XI.
REMOVAL OF
DAMS
Section 711.1.
APPROVAL OF PLANS REQUIRED. Prior to removal, a plan
for removal and revegetation must be approved by the Chief Engineer.
Section 711.2.
NOTICE TO
DOWNSTREAM LANDOWNERS. Downstream landowners must be notified of
the proposed action if any measure of flood protection would be lost due to the
removal of the dam.
Section 711.3.
RIGHTS OF OTHER LANDOWNERS. Downstream landowners and
those adjacent to the reservoir have the right to notice of projected changes
in streamflow patterns or reservoir levels, but do not have the right to
continued benefits at the dam owner's expense, unless the dam owner is
contractually bound to provide such benefits.
Section 711.4.
PROCEDURE FOR
BREACHING. The procedure for breaching must adequately guard
against downstream flooding, erosion, and sedimentation.
Section 711.5.
RESTORATION OF
ORIGINAL STREAM CHANNEL. Dimensions of the final cut through the
dam must be defined in the plan and must be of sufficient size to prevent
impounding water when streamflow equals the 100-year flood.
Section 711.6.
EROSION
PROTECTION. The plan must provide for establishment of vegetation
or other erosion protection measures sufficient to guard against deposition of
excessive sediment off site.
SUBTITLE
XII.
GLOSSARY
Unless clearly indicated by context, the following words and
terms, when used in this title, shall have meanings as defined below:
A.
Billing volume -
Normal storage less storage designed to contain sediment accumulation over the
life of the dam.
B.
Chief Engineer - The Deputy Director/Chief Engineer of
the Arkansas Soil and Water Conservation Commission.
C.
Commission - The
Arkansas Soil and Water Conservation Commission.
D.
Construction
costs - Estimated or actual material and labor costs, including
excavation, embankment placement, spillways, gates, valves, and conduits. Shall
not include costs of: land, reservoir clearing, engineering, water treatment
facilities, or other costs not directly related to construction of the
dam.
E.
Dam - Any barrier, including one for flood detention,
designed to impound liquid volumes. This shall not include highway, railroad or
other roadway embankments, including low water crossings that may temporarily
detain floodwater, levees designed to prevent inundation by floodwater, or
closed dikes to temporarily impound liquids in the event of emergencies and
those barriers not exempt by Sections
701.3
or
701.4
of this title.
F.
Effective crest of the dam - The elevation of the
lowest point on the crest of the dam excluding spillways.
G.
Executive
Director - The Executive Director of the Arkansas Soil and Water
Conservation Commission.
H.
Height of dam - The vertical distance from the
effective crest of the dam to the lowest elevation on the downstream toe of the
dam.
I.
Maximum
storage - The volume of the impoundment created by the dam at the
effective crest of the dam."
J.
Minimum release - Daily quantity of water which must
be released to preserve downstream riparian rights, permitted non-riparian
rights or to meet instream water needs including, but not limited to those of
fish and wildlife.
K.
Normal storage - The volume of the impoundment created
by the dam at the lowest uncontrolled spillway crest.
L.
PMF (probable
maximum flood) - The maximum runoff condition resulting from the most severe
combination of hydrologic and meteorologic conditions that are
reasonably-possible for a given watershed. The PMF is the maximum' runoff
computed from the spatial and temporal distribution of the PMP over, the
watershed.
M.
PMP (probable maximum precipitation) - The greatest
theoretical depth of precipitation (rainfall equivalent) for a given duration
that is physically possible over a given size storm area at a particular
geographical location at a certain time of the year..-
N.
Spillway design
flood (SDF) - The largest flood the spillway must pass without
overtopping a dam.