                                 CODE OF VIRGINIA

PROMULGATION OF REGULATIONS BY THE BOARD; GUIDANCE DOCUMENT (§ 10.1-605)

A. The Board shall adopt regulations to ensure that impounding structures in the
Commonwealth are properly and safely constructed, maintained and operated. Dam
safety regulations promulgated by the State Water Control Board shall remain in
full force until amended in accordance with applicable procedures.

B. The Board&#8217;s Impounding Structure Regulations shall not require any
impounding structure in existence or under a construction permit prior to July
1, 2010, that is currently classified as high hazard, or is subsequently found
to be high hazard through reclassification, to upgrade its spillway to pass a
rainfall event greater than the maximum recorded within the Commonwealth, which
shall be deemed to be 90 percent of the probable maximum precipitation.

   1. Such an impounding structure shall be determined to be in compliance with
   the spillway requirements of the regulations provided that (i) the impounding
   structure will pass two-thirds of the reduced probable maximum precipitation
   requirement described in this subsection and (ii) the dam owner certifies
   annually and by January 15 that such impounding structure meets each of the
   following conditions:
   				a. The owner has a current emergency action plan that is approved by the
   Board and that is developed and updated in accordance with the
   regulations;				b. The owner has exercised the emergency action plan in
   accordance with the regulations and conducts a table-top exercise at least
   once every two years;				c. The Department has verification that both the
   local emergency management coordinator and the Virginia Department of
   Emergency Management have on file current emergency action plans and updates
   for the impounding structure;				d. That conditions at the impounding
   structure are monitored on a daily basis and as dictated by the emergency
   action plan;				e. The impounding structure is inspected at least annually by
   a professional engineer and all observed deficiencies are addressed within 120
   days of such inspection;				f. The owner has a dam break inundation zone map
   developed in accordance with the regulations that is acceptable to the
   Department;				g. The owner is insured in an amount that will substantially
   cover the costs of downstream property losses to others that may result from a
   dam failure; and				h. The owner shall post the dam&#8217;s emergency action
   plan on his website, or upon the request of the owner, the Department or
   another state agency responsible for providing emergency management services
   to citizens agrees to post the plan on its website. If the Department or
   another state agency agrees to post the plan on its website, the owner shall
   provide the plan in a format suitable for posting.

   2. A dam owner who meets the conditions of subdivisions 1 a through 1 h, but
   has not provided record drawings to the Department for his impounding
   structure, shall submit a complete record report developed in accordance with
   the construction permit requirements of the Impounding Structure Regulations,
   excluding the required submittal of the record drawings.

   3. A dam owner who fails to submit certifications required by subdivisions 1 a
   through 1 h in a timely fashion shall not enjoy the presumption that such
   impounding structure is deemed to be in compliance with the spillway
   requirements of the Board&#8217;s Impounding Structure Regulations
   (4VAC50-20).

   4. Any dam owner who has submitted the certifications required by subdivisions
   1 a through 1 h shall make (i) such certifications, (ii) the emergency action
   plan required by subdivision 1 a, and (iii) the certificate of insurance
   required by subdivision 1 g available, upon request and within five business
   days, to any person. A dam owner may comply with the requirements of this
   subdivision by providing the same information on a website and directing the
   requestor to such website. A dam owner who fails to comply with this
   subdivision shall be subject to a civil penalty pursuant to &#xA7; 10.1-609.

C. The Board&#8217;s regulations shall establish an incremental damage analysis
procedure that permits the spillway design flood requirement for an impounding
structure to be reduced to the level at which dam failure shall not
significantly increase downstream hazard to life or property, provided that the
spillway design flood requirement shall not be reduced to below the 100-year
flood event for high or significant hazard impounding structures, or to below
the 50-year flood event for low hazard potential impounding structures.

D. The Board shall consider the impact of limited-use or private roadways with
low traffic volume and low public safety risk that are downstream from or across
an impounding structure in the determination of the hazard potential
classification of an impounding structure.

HISTORY: 1982, c. 583, § 62.1-115.2; 1986, c. 9; 1988, c. 891; 2010, cc. 249,
270; 2011, c. 323; 2025, cc. 228, 241.