4VAC50-20. Impounding Structure Regulations - Virginia Register of ...

TITLE 4. CONSERVATION AND NATURAL RESOURCES VIRGINIA SOIL AND WATER CONSERVATION BOARD Final Regulation
Title of Regulation: 4VAC50-20. Impounding Structure Regulations (amending
4VAC50-20-20 through 4VAC50-20-90, 4VAC50-20-150 through 4VAC50-20-240,
4VAC50-20-260 through 4VAC50-20-320; adding 4VAC50-20-51, 4VAC50-20-52,
4VAC50-20-54, 4VAC50-20-58, 4VAC50-20-59, 4VAC50-20-105, 4VAC50-20-125,
4VAC50-20-155, 4VAC50-20-165, 4VAC50-20-175, 4VAC50-20-177, 4VAC50-20-330,
4VAC50-20-340, 4VAC50-20-350, 4VAC50-20-360, 4VAC50-20-370, 4VAC50-20-380,
4VAC50-20-390, 4VAC50-20-400; repealing 4VAC50-20-100 through 4VAC50-20-
140, 4VAC50-20-250).
Statutory Authority: §10.1-605 of the Code of Virginia.
Effective Date: September 26, 2008.
Agency Contact: David C. Dowling, Policy, Planning, and Budget Director,
Department of Conservation and Recreation, 203 Governor Street, Suite 302,
Richmond, VA 23219, telephone (804) 786-2291, FAX (804) 786-6141, or email
david.dowling@dcr.virginia.gov.
Summary:
This regulatory action amends the Virginia Soil and Water Conservation
Board's Impounding Structure Regulations to protect the safety and welfare
of the public and their property from the impact of dam failures. The key
elements of this regulation will:
1. Revise the dam hazard potential classification system from four
categories (Class I, II, III, and IV) to three hazard classifications
(High, Significant, and Low);
2. Specify that spillway design requirements are applicable to all state
regulated dams regardless of the date they were built;
3. Modify the spillway design requirements to enhance public safety and
reduce subjectivity (The final regulations further refined and simplified
the requirements of Table 1 as well as created "special criteria" for
certain low hazard impounding structures, resulting in a 57% reduction in
estimated potential spillway upgrade costs for regulated dams from the
proposed regulations to the final regulations);
4. Allow for the reduction of the spillway design flood requirements
through incremental damage assessments for all qualifying dams;
5. Establish dam break inundation zone mapping requirements to identify
areas that are subject to flooding during a dam failure;
6. Expand emergency action plan requirements for High and Significant
Hazard Potential dams and emergency preparedness plan requirements for Low
Hazard Potential dams;
7. Establish permit application fees for the administration of the Dam
Safety Program;
8. Incorporate reporting standards into the regulations;
9. Reorganize, clarify, and expand sections related to permitting
procedures; and
10. Update sections related to inspections, enforcement, and unsafe
conditions.
Changes from the proposed include simplification of spillway design flood
requirements (Table 1) to remove size classes and in certain cases reduce
spillway design standards, inclusion of exemptions for low hazard
impounding structures meeting specified criteria, and the reduction or
elimination of fees associated with both Regular and Conditional Operation
and Maintenance Certificates and Incremental Damage Assessment review.
Summary of Public Comments and Agency's Response: A summary of comments
made by the public and the agency's response may be obtained from the
promulgating agency or viewed at the office of the Registrar of
Regulations.
4VAC50-20-20. General provisions.
A. This chapter provides for the proper and safe design, construction,
operation and maintenance of impounding structures to protect public
safety. This chapter shall not be construed or interpreted to relieve the
owner or operator of any impoundment or impounding structure of any legal
duties, obligations or liabilities incident to ownership, design,
construction, operation or maintenance.
B. Approval by the board of proposals for an impounding structure shall in
no manner be construed or interpreted as approval to capture or store
waters. For information concerning approval to capture or store waters, see
Chapter 8 (§62.1-107) of Title 62.1 of the Code of Virginia, and other
provisions of law as may be applicable.
C. In promulgating this chapter, the board recognizes that no impounding
structure can ever be completely "fail-safe," because of incomplete
understanding of or uncertainties associated with natural (earthquakes and
floods) and manmade (sabotage) destructive forces; with material behavior
and response to those forces; and with quality control during construction. D. Any All engineering analysis analyses required by this chapter such as,
including but not limited to, plans, specifications, hydrology, hydraulics
and inspections shall be conducted or overseen by and bear the seal of a
professional engineer licensed to practice in Virginia.
E. Design, inspection and maintenance of impounding structures shall be
conducted utilizing competent, experienced, engineering judgment that takes
into consideration factors including but not limited to local topography
and meteorological conditions.
E. F. The official forms as [ called for ] by [ noted ] in this chapter are
available from the director department at the department's website.
4VAC50-20-30. Definitions.
The following words and terms when used in this chapter shall have the
following meanings unless the context clearly indicates otherwise:
"Acre-foot" means a unit of volume equal to 43,560 cubic feet or 325,853
gallons (one (equivalent to one foot of depth over one acre of area).
"Agricultural purpose" means the production of an agricultural commodity as
defined in §3.1-249.27 of the Code of Virginia that requires the use of
impounded waters.
"Agricultural purpose dams" means [ dams impounding structures ] which are
less than 25 feet in height or which create a maximum impoundment smaller
than 100 acre-feet, and certified by the owner on official forms as
constructed, maintained or operated primarily for agricultural purposes.
"Alteration" means changes to an impounding structure that could alter or
affect its structural integrity. Alterations include, but are not limited
to, changing the height or otherwise enlarging the dam, increasing normal
pool or principal spillway elevation or physical dimensions, changing the
elevation or physical dimensions of the emergency spillway, conducting
necessary structural repairs or structural maintenance, or removing the
impounding structure. [ Structural maintenance does not include routine
maintenance. ]
"Alteration permit" means a permit required for changes any alteration to
an impounding structure that could alter or affect its structural
integrity. Alterations requiring a permit include, but are not limited to:
changing the height, increasing the normal pool or principal spillway
elevation, changing the elevation or physical dimensions of the emergency
spillway or removing the impounding structure.
"Board" means the Virginia Soil and Water Conservation Board.
"Conditional operation and maintenance certificate Operation and
Maintenance Certificate" means a certificate required for impounding
structures with deficiencies.
"Construction" means the construction of a new impounding structure.
"Construction permit" means a permit required for the construction of a new
impounding structure.
"Dam break inundation zone" means the area downstream of a dam that would
be inundated or otherwise directly affected by the failure of a dam.
"Department" means the Virginia Department of Conservation and Recreation.
"Design flood" means the calculated volume of runoff and the resulting peak
discharge utilized in the evaluation, design, construction, operation and
maintenance of the impounding structure.
"Design freeboard" means the vertical distance between the maximum
elevation of the design flood and the top of the impounding structure.
"Director" means the Director of the Department of Conservation and
Recreation or his designee.
"Drill" means a type of emergency action plan exercise that tests,
develops, or maintains skills in an emergency response procedure. During a
drill, participants perform an in-house exercise to verify telephone
numbers and other means of communication along with the owner's response. A
drill is considered a necessary part of ongoing training.
"Emergency Action Plan or EAP" means a formal document that recognizes
potential impounding structure emergency conditions and specifies
preplanned actions to be followed to minimize loss of life and property
damage. The EAP specifies actions the owner must take to minimize or
alleviate emergency conditions at the impounding structure. It contains
procedures and information to assist the owner in issuing early warning and
notification messages to responsible emergency management authorities. It
shall also contain dam break inundation zone maps as required to show
emergency management authorities the critical areas for action in case of
emergency.
"Emergency Action Plan Exercise" means an activity designed to promote
emergency preparedness; test or evaluate EAPs, procedures, or facilities;
train personnel in emergency management duties; and demonstrate operational
capability. In response to a simulated event, exercises should consist of
the performance of duties, tasks, or operations very similar to the way
they would be performed in a real emergency. An exercise may include but
not be limited to drills and tabletop exercises.
"Emergency Preparedness Plan" means a formal document prepared