Virginia Administrative Code › Title 4 - CONSERVATION AND NATURAL RESOURCES › Agency 50 - VIRGINIA SOIL AND WATER CONSERVATION BOARD › Chapter 20 - IMPOUNDING STRUCTURE REGULATIONS › Part II - Permit Requirements › Section 4VAC50-20-80 - Alterations permits

Current through Register Vol. 40, No. 24, July 15, 2024
A. Alterations
				  which would potentially affect the structural integrity of an impounding
				  structure 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 repairs or structural maintenance, or
				  removing the impounding structure. Structural maintenance does not include
				  routine maintenance.
B. An
				  applicant for an Alteration Permit shall submit a design report. A form for the
				  design report is available from the department (Design Report for the
				  Construction or Alteration of Virginia Regulated Impounding Structures). The
				  design report shall be prepared in accordance with
				  4VAC50-20-240. The design report
				  shall include, but not be limited to, the following information:
1. Project information including a
				  description and benefits of the proposed alteration, name of the impounding
				  structure, inventory number if available, name of the reservoir, and the
				  purpose of the reservoir.
2. The
				  hazard potential classification in conformance with Table 1 in
				  4VAC50-20-50.
3. Location of the impounding structure
				  including the city or county, number of feet or miles upstream or downstream of
				  a highway and the highway number, name of the river or the stream, and the
				  latitude and longitude.
4. Owner's
				  name or representative if corporation, mailing address, residential and
				  business telephone numbers, and other means of communication.
5. Owner's engineer's name, firm,
				  professional engineer Virginia number, mailing address, and business telephone
				  number.
6. Impounding structure
				  data including type of material (earth, concrete, masonry or other) and the
				  following configurations (note both existing and design configurations for
				  each):
a. Top of impounding structure
				  (elevation);
b. Downstream toe -
				  lowest (elevation);
c. Height of
				  impounding structure (feet);
d.
				  Crest length - exclusive of spillway (feet);
e. Crest width (feet);
f. Upstream slope (horizontal to vertical);
				  and
g. Downstream slope (horizontal
				  to vertical).
7.
				  Reservoir data including the following (note both existing and design
				  configurations for each):
a. Maximum capacity
				  (acre-feet);
b. Maximum pool
				  (elevation);
c. Maximum pool
				  surface area (acres);
d. Normal
				  capacity (acre-feet);
e. Normal
				  pool (elevation);
f. Normal pool
				  surface area (acres); and
g.
				  Freeboard (feet).
8.
				  Spillway data including the type, construction material, design configuration,
				  and invert elevation for the low level drain, the principal spillway, and the
				  emergency spillway.
9. Watershed
				  data including drainage area (square miles); type and extent of watershed
				  development; time of concentration (hours); routing procedure; spillway design
				  flood used and state source; design inflow hydrograph volume (acre-feet), peak
				  inflow (cfs), and rainfall duration (hours); and freeboard during passage of
				  the spillway design flood (feet).
10. Evidence that the local government has
				  been notified of the alteration and repair plan.
11. Plans and specifications as required by
				  4VAC50-20-310. The plan view of the
				  impounding structure site should represent all significant structures and
				  improvements that illustrate the location of all proposed work.
12. A report of the geotechnical
				  investigations of the foundation soils, bedrock, or both in the areas affected
				  by the proposed alterations and of the materials to be used to alter the
				  impounding structure.
13. Design
				  assumptions and analyses sufficient to indicate that the impounding structure
				  will be stable during the alteration of the impounding structure under all
				  conditions of reservoir operations.
14. Calculations and assumptions relative to
				  design of the improved spillway or spillways, if applicable.
15. Provisions to ensure that the impounding
				  structure and appurtenances during the alteration will be protected against
				  unacceptable deterioration or erosion due to freezing and thawing, wind, wave
				  action and rain or any combination thereof.
16. Other pertinent design data, assumptions
				  and analyses commensurate with the nature of the particular impounding
				  structure and specific site conditions, including when required by this
				  chapter, a plan and water surface profile of the dam break inundation
				  zone.
17. If applicable, a
				  description of the techniques to be used to divert stream flow during
				  alteration work so as to prevent hazard to life, health and property, including
				  a detailed plan and procedures to maintain a stable impounding structure during
				  storm events, a drawing showing temporary diversion devices, and a description
				  of the potential impoundment during the alteration. Such diversion plans shall
				  be in accordance with the applicable environmental laws.
18. A plan for project construction
				  monitoring and quality control testing to confirm that materials used in the
				  alteration work and that performance standards meet the design requirements set
				  forth in the specifications.
19.
				  Certification by the owner's engineer that the information provided pursuant to
				  this subsection is true and correct in their professional judgment. Such
				  certification shall include the engineer's signature, printed name, Virginia
				  number, date, and the engineer's Virginia seal.
20. Owner's signature certifying receipt of
				  the information provided pursuant to this subsection.