Title of Regulation: 4VAC50-20. Impounding Structure Regulations (amending 4VAC50-20-30, 4VAC50-20-40, 4VAC50-20-52, 4VAC50-20-54, 4VAC50-20-177, 4VAC50-20-200, 4VAC50-20-340; adding 4VAC50-20-45, 4VAC50-20-101, 4VAC50-20-102, 4VAC50-20-103, 4VAC50-20-104, 4VAC50-20-195, 4VAC50-20-375, 4VAC50-20-395).

Statutory Authority: § 10.1-605 of the Code of Virginia.

Public Hearing Information: No public hearings are scheduled.

Public Comment Deadline: October 24, 2012.

Effective Date: November 8, 2012.

Agency Contact: David C. Dowling, Policy and Planning 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.

Basis: The Virginia Dam Safety Act (§ 10.1-604 et seq. of the Code of Virginia) ensures public safety through the proper and safe design, construction, operation, and maintenance of impounding structures in the Commonwealth. This is accomplished through the effective administration of the Virginia Dam Safety Program. Authority for the program rests with the Virginia Soil and Water Conservation Board and it is administered on behalf of the board by the Department of Conservation and Recreation's Division of Dam Safety and Floodplain Management. The program focuses on enhancing public safety through bringing all impounding structures of regulated size under Regular Operation and Maintenance Certificates. Pursuant to § 10.1-605, the board is directed to promulgate regulations for impounding structures. Further, the board reserves the sole right to promulgate regulations.

The three items that the board directed the department and the regulatory advisory panel to consider in the regulatory action were as follows:

1. Develop regulations (considering existing guidance) that consider the impact of downstream limited-use or private roadways with low traffic volume and low public safety risk on the determination of the hazard potential classification of an impounding structure;

2. Develop regulations that provide a method to conduct a simplified dam break inundation zone analysis; and

3. Develop regulations that set out the necessary requirements to obtain a general permit for a low hazard impounding structure.

These actions were predicated on the following legislation and information that was closely considered in the development of the regulations:

Item 1:

• Chapter 270 of the 2010 Virginia Acts of Assembly (HB438 - Delegate David J. Toscano) amended § 10.1-605 C of the Code of Virginia to direct that "[t]he 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."

• Chapter 41 of the 2010 Virginia Acts of Assembly (SB244 - Senator John C. Watkins) resulted in the codification of § 10.1-605.2 of the Code of Virginia that stipulates "[t]hat the Virginia Soil and Water Conservation Board shall, in accordance with the Administrative Process Act (§ 2.2-4000 et seq.), adopt regulations that consider the impact of downstream limited-use or private roadways with low traffic volume and low public safety risk on the determination of the hazard potential classification of an impounding structure under the Dam Safety Act (§ 10.1-604 et seq.)."

• During 2010, in partial response to these legislative directives, the Director of the Department approved on November 30, 2010, a "Guidance Document on Roadways On or Below Impounding Structures." The guidance was strongly considered in the construct of the regulations.

Item 2:

• Chapter 637 of the 2011 Virginia Acts of Assembly (SB1060 - Senator Ryan T. McDougle) created § 10.1-604.1 titled "Determination of hazard potential class" with a subsection C that specifies that "[t]he Board may adopt regulations in accordance with § 10.1-605 to establish a simplified methodology for dam break inundation zone analysis."

Item 3:

• Chapter 637 of the 2011 Virginia Acts of Assembly (SB1060 - Senator Ryan T. McDougle) created § 10.1-605.3 titled "General permit for certain impounding structures" with a subsection A that specifies that "[t]he Board shall develop a general permit for the regulation of low hazard potential impounding structures in accordance with § 10.1-605."

Purpose: The changes being advanced by this regulatory action are largely in response to requirements placed in the Code of Virginia during the last several General Assembly Sessions that directed the board to:

1. Adopt regulations that consider the impact of downstream limited-use or private roadways with low traffic volume and low public safety risk on the determination of the hazard potential classification of an impounding structure under the Dam Safety Act (§ 10.1-604 et seq.).

2. Adopt regulations in accordance with § 10.1-605 to establish a simplified methodology for dam break inundation zone analysis.

3. Develop a general permit for the regulation of low hazard potential impounding structures in accordance with § 10.1-605.

Accordingly, the provisions of the regulations being advanced will result in reduced and streamlined compliance requirements that will provide less costly services for mapping, provide additional mechanisms through which a hazard potential classification and related spillway design flood may be reduced through new provisions including low volume roadway and expanded incremental damage analysis considerations, as well as provide for a streamlined general permit process for the regulation of low hazard potential impounding structures. The provisions of this regulatory action are intended to provide true economic and regulatory relief for all low hazard potential dam owners and additional opportunities for regulatory relief for high and significant hazard potential dam owners while remaining mindful of the Commonwealth's public safety obligations.

Rationale for Using Fast-Track Process: This rulemaking is expected to be noncontroversial as the majority of the provisions included in these regulations largely incorporate requirements set out in the Code where limited discretion is offered and are being advanced to provide true economic and regulatory relief to those regulated. Where limited latitude was available in developing regulatory provisions, there was general consensus regarding the language included from a regulatory advisory panel composed of private, local, and state dam owners and engineers that was assembled to provide sound recommendations to the department and board regarding these regulatory improvements.

Substance: The key substantive changes included in this regulatory action involve the following:

1. Amending the hazard potential classification section (4VAC50-20-40) to:

a. Exclude roadways with an annual average daily traffic volume of 400 vehicles or less from consideration as major roadways or secondary roadways that traditionally lead to hazard classifications of high or significant respectively.

b. Establish that the department may be requested by a dam owner in specified situations to conduct a simplified dam break inundation zone analysis to determine whether the impounding structure has a low hazard potential classification.

c. Specify that if the department finds that an impounding structure appears to have a low hazard potential classification that the owner may be eligible for general permit coverage.

d. Specify that an incremental damage analysis may be utilized as part of hazard potential classification by the owners engineer.

2. Establishing a new section (4VAC50-20-45) on low volume roadways that tracks the guidance previously approved by the director and specifically:

a. Sets out the analysis methods by which a determination may be made whether a road is impacted by a dam failure.

b. Specifies that an incremental damage analysis may be utilized to refine what roadways should be considered impacted.

c. Establishes that an impounding structure may qualify for low hazard potential classification based on annual average daily traffic (AADT) volume if other downstream factors do not exist that would otherwise raise the hazard classification.

d. Establishes accepted methodologies for determining a road's AADT.

e. Sets an AADT volume of 400 vehicles or less as the number where a roadway may be considered "limited use" and how an impounding structure may qualify for low hazard potential classification.

f. Requires that the Emergency Preparedness Plan consider these "limited use" roadways regarding proper notifications during emergency conditions.

3. Amending the incremental damage analysis section (4VAC50-20-52) to establish processes by which the potential hazard potential classification of an impounding structure may be lowered based on the results of an incremental damage analysis.

4. Amending the dam break inundation zone mapping section (4VAC50-20-54) to:

a. Clarify that the department may complete for a dam owner a simplified dam break inundation zone map and analysis in accordance with this section.

b. Specify that Emergency Action and Emergency Preparedness Plans shall include maps for the sunny day dam failure and a probable maximum flood with a dam failure.

c. Specify the general deliverables and administrative processes associated with the department conducting a simplified dam break inundation zone analysis.

5. Establishing a new section (4VAC50-20-101) on general permit requirements for low hazard potential impounding structures that specifies that the owner shall be subject to the following requirements:

a. The dam has a spillway design able to safely pass a 100-year flood.

b. The owner shall develop and maintain an emergency preparedness plan.

c. The owner shall perform an annual inspection and maintain such records and make them available to the department upon request.

d. The owner shall ensure that the impounding structure is properly maintained and operated and shall have operation and maintenance plans and schedules available to the department for inspection upon request.

e. The owner shall file a dam break inundation zone map with the department and the locality or localities.

f. The owner shall notify the specified authorities in the event of a failure or imminent failure of the impounding structure.

6. Establishing a new section (4VAC50-20-102) regarding registering for coverage under the general permit for low hazard potential impounding structures that specifies that the owner shall submit a complete and accurate registration statement and sets out the eight components of that submittal.

Issues: The regulations being advanced provide advantages (reduced and streamlined compliance requirements) to those impounding structure owners regulated under the Virginia Dam Safety Act and its attendant regulations by providing less costly services for mapping, providing additional mechanisms through which a hazard potential classification and related spillway design flood may be reduced through new provisions including low volume roadway and expanded incremental damage analysis considerations, as well as providing for a streamlined general permit process for the regulation of low hazard potential impounding structures. The provisions of this regulatory action are intended to provide true economic and regulatory relief for all low hazard potential dam owners and additional opportunities for regulatory relief for high and significant hazard potential dam owners while remaining mindful of the Commonwealth's public safety obligations. Downstream residents and property owners below regulated dams should not be disadvantaged or their safety affected by these actions as they largely provide for streamlined processes, provide for less costly services, and reduce dam standards only where risks are low and reasonable to do such.

Department of Planning and Budget's Economic Impact Analysis:

Summary of the Proposed Amendments to Regulation. The Virginia Soil and Water Conservation Board (Board) proposes changes to these regulations in response to requirements placed in the Code of Virginia during the last several General Assembly Sessions that directed the Board to: 1) adopt regulations that consider the impact of downstream limited-use or private roadways with low traffic volume and low public safety risk on the determination of the hazard potential classification of an impounding structure under the Dam Safety Act ( § 10.1-604 et seq.), 2) adopt regulations in accordance with § 10.1-605 to establish a simplified methodology for dam break inundation zone analysis, and 3) develop a general permit for the regulation of low hazard potential impounding structures in accordance with § 10.1-605.

The proposed regulations contain provisions that address these Code requirements and offer a balance between public safety and the reduced risks associated with low hazard impounding structures. The key elements of the proposed amendments to these regulations include: 1) provisions to allow for the use of incremental damage analyses to modify hazard potential classifications, 2) the use of an annual average daily traffic (AADT) volume of 400 vehicles or less as the number where a roadway may be considered "limited use" and processes by which such an impounding structure may qualify for low hazard potential classification, 3) the implementation of a streamlined general permit process with reduced requirements, and 4) the ability for the Department to assist specified dam owners by conducting simplified dam break inundation zone analyses for them.

Result of Analysis. The benefits likely exceed the costs for all proposed changes.

Estimated Economic Impact. Overall, public and private dam owners will be positively affected as some will benefit from reduced dam safety compliance costs associated with proposed mechanisms through which hazard potential classification may be reduced. Proposed new provisions including low volume roadway and expanded incremental damage analysis considerations. The Department of Conservation and Recreation does not believe that the safety of downstream residents and property owners will be negatively affected by the proposed amendments as they largely provide for streamlined processes, provide for less costly services, and reduce required dam standards only where risks are low.

Businesses and Entities Affected. The proposed changes affect regulated public and private dam owners that are subject to these regulations as well as downstream residents and property owners who would be potentially affected upon a dam failure. Approximately 1600 dams across the Commonwealth could be affected by this regulatory action. Of these dams, as of December 2011, slightly over 220 were classified as high hazard, almost 400 as significant hazard, and over 940 as low hazard. The low hazard dam owners will benefit the most from the proposed new provisions of these regulations. A number of these dam owners may be small businesses.

Localities Particularly Affected. Dams exist throughout the Commonwealth. The proposal to classify some impounding structures as low hazard due partially to low traffic volume would likely affect less densely populated localities more than relatively congested portions of Virginia.

Projected Impact on Employment. The proposal amendments are unlikely to significantly affect employment.

Effects on the Use and Value of Private Property. The proposed amendments will likely reduce dam safety compliance costs and consequently somewhat increase the net value of private property that includes impounding structures.

Small Businesses: Costs and Other Effects. The proposed amendments will likely reduce dam safety compliance costs for some small businesses that own dams.

Small Businesses: Alternative Method that Minimizes Adverse Impact. The proposed amendments do not adversely impact small businesses.

Real Estate Development Costs. The proposed amendments will potentially reduce development costs for qualifying properties that include impounding structures.

Legal Mandate. The Department of Planning and Budget (DPB) has analyzed the economic impact of this proposed regulation in accordance with § 2.2-4007.04 of the Administrative Process Act and Executive Order Number 14 (10). Section 2.2-4007.04 requires that such economic impact analyses include, but need not be limited to, the projected number of businesses or other entities to whom the regulation would apply, the identity of any localities and types of businesses or other entities particularly affected, the projected number of persons and employment positions to be affected, the projected costs to affected businesses or entities to implement or comply with the regulation, and the impact on the use and value of private property. Further, if the proposed regulation has adverse effect on small businesses, § 2.2-4007.04 requires that such economic impact analyses include (i) an identification and estimate of the number of small businesses subject to the regulation; (ii) the projected reporting, recordkeeping, and other administrative costs required for small businesses to comply with the regulation, including the type of professional skills necessary for preparing required reports and other documents; (iii) a statement of the probable effect of the regulation on affected small businesses; and (iv) a description of any less intrusive or less costly alternative methods of achieving the purpose of the regulation. The analysis presented above represents DPB's best estimate of these economic impacts.

Agency's Response to Economic Impact Analysis: The Department of Conservation and Recreation concurs with the economic impact analysis prepared by the Department of Planning and Budget regarding the Impounding Structure Regulations (4VAC50-20).

Summary:

The amendments address the Code of Virginia requirements of the board to (i) adopt regulations that consider the impact of downstream limited-use or private roadways with low traffic volume and low public safety risk on the determination of the hazard potential classification of an impounding structure under the Dam Safety Act (§ 10.1-604 et seq.); (ii) adopt regulations in accordance with § 10.1-605 to establish a simplified methodology for dam break inundation zone analysis; and (iii) develop a general permit for the regulation of low hazard potential impounding structures in accordance with § 10.1-605.

The key elements of the regulations include:

1. Provisions to allow for the use of incremental damage analyses to modify hazard potential classifications;

2. The use of an annual average daily traffic (AADT) volume of 400 vehicles or less as the number where a roadway may be considered limited use and processes by which such an impounding structure may qualify for low hazard potential classification;

3. The implementation of a streamlined general permit process with reduced requirements for low hazard dams; and

4. The ability for the department to assist specified dam owners by conducting simplified dam break inundation zone analyses for them.

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 (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 § 3.2-3900 of the Code of Virginia that requires the use of impounded waters.

"Agricultural purpose dams" means impounding structures which are less than 25 feet in height or which create a maximum impoundment smaller than 100 acre-feet, and 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 any alteration to an impounding structure.

"Annual average daily traffic" or "AADT" means the total volume of vehicle traffic of a highway or road for a year divided by 365 days and is a measure used in transportation planning and transportation engineering of how busy a road is.

"Board" means the Virginia Soil and Water Conservation Board.

"Conditional 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.

"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 for Low Hazard impounding structures that provides maps and procedures for notifying owners of downstream property that may be impacted by an emergency situation at an impounding structure.

"Existing impounding structure" means any impounding structure in existence or under a construction permit prior to July 1, 2010.

"Freeboard" means the vertical distance between the maximum water surface elevation associated with the spillway design flood and the top of the impounding structure.

"Height" means the hydraulic height of an impounding structure. If the impounding structure spans a stream or watercourse, height means the vertical distance from the natural bed of the stream or watercourse measured at the downstream toe of the impounding structure to the top of the impounding structure. If the impounding structure does not span a stream or watercourse, height means the vertical distance from the lowest elevation of the downstream limit of the barrier to the top of the impounding structure.

"Impounding structure" or "dam" means a man-made structure, whether a dam across a watercourse or structure outside a watercourse, used or to be used to retain or store waters or other materials. The term includes: (i) all dams that are 25 feet or greater in height and that create an impoundment capacity of 15 acre-feet or greater, and (ii) all dams that are six feet or greater in height and that create an impoundment capacity of 50 acre-feet or greater. The term "impounding structure" shall not include: (a) dams licensed by the State Corporation Commission that are subject to a safety inspection program; (b) dams owned or licensed by the United States government; (c) dams operated primarily for agricultural purposes which are less than 25 feet in height or which create a maximum impoundment capacity smaller than 100 acre-feet; (d) water or silt retaining dams approved pursuant to § 45.1-222 or § 45.1-225.1 of the Code of Virginia; or (e) obstructions in a canal used to raise or lower water.

"Impoundment" means a body of water or other materials the storage of which is caused by any impounding structure.

"Life of the impounding structure" and "life of the project" mean that period of time for which the impounding structure is designed and planned to perform effectively, including the time required to remove the structure when it is no longer capable of functioning as planned and designed.

"Maximum impounding capacity" means the volume of water or other materials in acre-feet that is capable of being impounded at the top of the impounding structure.

"New construction" means any impounding structure issued a construction permit or otherwise constructed on or after July 1, 2010.

"Normal or typical water surface elevation" means the water surface elevation at the crest of the lowest ungated outlet from the impoundment or the elevation of the normal pool of the impoundment if different than the water surface elevation at the crest of the lowest ungated outlet. For calculating sunny day failures for flood control impounding structures, stormwater detention impounding structures, and related facilities designed to hold back volumes of water for slow release, the normal or typical water surface elevation shall be measured at the crest of the auxiliary or emergency spillway.

"Operation and Maintenance Certificate" means a certificate required for the operation and maintenance of all impounding structures.

"Owner" means the owner of the land on which an impounding structure is situated, the holder of an easement permitting the construction of an impounding structure and any person or entity agreeing to maintain an impounding structure. The term "owner" may include the Commonwealth or any of its political subdivisions, including but not limited to sanitation district commissions and authorities, any public or private institutions, corporations, associations, firms or companies organized or existing under the laws of this Commonwealth or any other state or country, as well as any person or group of persons acting individually or as a group.

"Planned land use" means land use that has been approved by a locality or included in a master land use plan by a locality, such as in a locality's comprehensive land use plan.

"Spillway" means a structure to provide for the controlled release of flows from the impounding structure into a downstream area.

"Stage I Condition" means a flood watch or heavy continuous rain or excessive flow of water from ice or snow melt.

"Stage II Condition" means a flood watch or emergency spillway activation or impounding structure overtopping where a failure may be possible.

"Stage III Condition" means an emergency spillway activation or impounding structure overtopping where imminent failure is probable.

"Sunny day dam failure" means the failure of an impounding structure with the initial water level at the normal reservoir level, usually at the lowest ungated principal spillway elevation or the typical operating water level.

"Tabletop Exercise" means a type of emergency action plan exercise that involves a meeting of the impounding structure owner and the state and local emergency management officials in a conference room environment. The format is usually informal with minimum stress involved. The exercise begins with the description of a simulated event and proceeds with discussions by the participants to evaluate the EAP and response procedures and to resolve concerns regarding coordination and responsibilities.

"Top of the impounding structure" means the lowest point of the nonoverflow section of the impounding structure.

"Watercourse" means a natural channel having a well-defined bed and banks and in which water normally flows.

4VAC50-20-40. Hazard potential classifications of impounding structures.

A. Impounding structures shall be classified in one of three hazard classifications as defined in subsection B of this section and Table 1.

B. For the purpose of this chapter, hazards pertain to potential loss of human life or damage to the property of others downstream from the impounding structure in event of failure or faulty operation of the impounding structure or appurtenant facilities. Hazard potential classifications of impounding structures are as follows:

1. High Hazard Potential is defined where an impounding structure failure will cause probable loss of life or serious economic damage. "Probable loss of life" means that impacts will occur that are likely to cause a loss of human life, including but not limited to impacts to residences, businesses, other occupied structures, or major roadways. Economic damage may occur to, but not be limited to, building(s), industrial or commercial facilities, public utilities, major roadways, railroads, personal property, and agricultural interests. "Major roadways" include, but are not limited to, interstates, primary highways, high-volume urban streets, or other high-volume roadways, except those having an AADT volume of 400 vehicles or less in accordance with 4VAC50-20-45.

2. Significant Hazard Potential is defined where an impounding structure failure may cause the loss of life or appreciable economic damage. "May cause loss of life" means that impacts will occur that could cause a loss of human life, including but not limited to impacts to facilities that are frequently utilized by humans other than residences, businesses, or other occupied structures, or to secondary roadways. Economic damage may occur to, but not be limited to, building(s), industrial or commercial facilities, public utilities, secondary roadways, railroads, personal property, and agricultural interests. "Secondary roadways" include, but are not limited to, secondary highways, low-volume urban streets, service roads, or other low-volume roadways, except those having an AADT volume of 400 vehicles or less in accordance with 4VAC50-20-45.

3. Low Hazard Potential is defined where an impounding structure failure would result in no expected loss of life and would cause no more than minimal economic damage. "No expected loss of life" means no loss of human life is anticipated.

C. The hazard potential classification shall be proposed by the owner and shall be subject to approval by the board. To support the appropriate hazard potential classification, dam break analysis shall be conducted by the owner's engineer or the department in accordance with one of the following alternatives and utilizing procedures set out in 4VAC50-20-54. Present and planned land-use for which a development plan has been officially approved by the locality in the dam break inundation zones downstream from the impounding structure shall be considered in determining the classification.

1. The owner of an impounding structure that does not currently hold a regular or conditional certificate from the board, or the owner of an impounding structure that is already under certificate but the owner believes that a condition has changed downstream of the impounding structure that may reduce its hazard potential classification, may request in writing that the department conduct a simplified dam break inundation zone analysis to determine whether the impounding structure has a low hazard potential classification. The owner shall pay a fee to the department in accordance with 4VAC50-20-395 for conducting each requested analysis. The department shall address requests in the order received and shall strive to complete analysis within 90 days; or

2. The owner may propose a hazard potential classification that shall be subject to approval by the board. To support the proposed hazard potential classification, an analysis shall be conducted by the owner's engineer and submitted to the department. The hazard potential classification shall be certified by the owner.

D. Findings of the analysis conducted pursuant to subsection C of this section shall result in one of the following actions:

1. For findings by the department resulting from analyses conducted in accordance with subdivision C 1 of this section:

a. If the department finds that the impounding structure appears to have a low hazard potential classification, the owner may be eligible for general permit coverage in accordance with 4VAC50-20-103.

b. If the department finds that the impounding structure appears to have a high or significant hazard potential classification, the owner's engineer shall provide further analysis in accordance with the procedures set out in 4VAC50-20-54 and this chapter. The owner may be eligible for grant assistance from the Dam Safety, Flood Prevention and Protection Assistance Fund in accordance with Article 1.2 (§ 10.1-603.16 et seq.) of Chapter 6 of Title 10.1 of the Code of Virginia.

2. For findings by the owner's engineer resulting from analyses conducted in accordance with subdivision C 2 of this section:

a. If the engineer finds that the impounding structure has a low hazard potential classification, the owner may be eligible for general permit coverage in accordance with 4VAC50-20-103; or

b. If the engineer finds that the impounding structure appears to have a high or significant hazard potential classification, then the owner shall comply with the applicable certification requirements set out in this chapter.

E. An incremental damage analysis in accordance with 4VAC50-20-52 may be utilized as part of a hazard potential classification by the owner's engineer.

F. Impounding structures shall be subject to reclassification by the board as necessary.

4VAC50-20-45. Hazard potential classifications based on low volume roadways.

A. All impacted public and private roadways downstream or across an impounding structure shall be considered in determining hazard potential classification. To determine whether a road is impacted by a dam failure, one of the following methodologies shall be utilized:

1. Section IV, Part D of the United States Department of Interior, Bureau of Reclamation's ACER Technical Memorandum No. 11, 1988;

2. An approach to determining impacts to roadways found in any document that is on the list of acceptable references set out in 4VAC50-20-320. The owner's engineer shall reference the methodology utilized in their submittal to the department; or

3. An approach to determine any roadway that would be overtopped, at any depth, by a dam failure under any flood or nonflood condition, including but not limited to probable maximum flood, spillway design flood, or flood from sunny day dam failure, as determined using analysis procedures set out in 4VAC50-20-54.

In all cases, an owner may use an incremental damage analysis conducted in accordance with 4VAC50-20-52 to further refine what roads should be considered impacted.

B. In certain cases, an impounding structure may qualify for a low hazard potential classification in spite of a potential impact to a downstream public or private roadway. If a roadway is found to be impacted in accordance with subsection A of this section, and other factors such as downstream residences, businesses, or other concerns as set forth in this chapter that would raise the hazard potential classification do not exist, such classification may be adjusted in accordance with this section dependent on vehicle traffic volume, based on AADT.

C. For the purposes of determining AADT volume, one of the following techniques may be utilized using data obtained within the last year except as otherwise set out in subdivision 1 of this subsection:

1. The AADT volumes available in the most recent published Daily Traffic Volume Estimates from the Virginia Department of Transportation (VDOT) for the road segment nearest the impounding structure may be utilized. This information is available from VDOT at http://www.virginiadot.org/info/ct-TrafficCounts.asp;

2. Data developed by a local government may be utilized where the locality conducts its own traffic counts;

3. Where AADT volumes are not available from VDOT or a locality, an Average Daily Traffic trip rate that meets the standards set forth in the Institute for Traffic Engineers (ITE) Trip Generation information report, 8th Edition, 2008 (available for ordering online at http://www.ite.org/emodules/scriptcontent/orders/ProductDetail.cfm?pc=IR-016F) may be utilized if practicable; or

4. In all cases, average daily traffic volumes may also be established by a traffic count that meets VDOT standards and is conducted or overseen by the owner's engineer or otherwise approved by the department's regional engineer.

D. Where it can be demonstrated that a public or private roadway has limited usage and that the hazard potential classification is being determined based solely upon impacts to roadways, the roadway may be considered to be "limited use" and the impounding structure may be considered a low hazard potential impounding structure despite the presence of the roadway. Such roadways, located either across or below an impounding structure, are those that result in an AADT volume of 400 vehicles or less.

Where a downstream analysis finds that multiple limited use roadways may be impacted by an impounding structure failure, the traffic volumes of those limited use roadways, determined in accordance with subsection B of this section, shall be combined for the purposes of determining the impounding structure's hazard potential classification unless it can be demonstrated that the traffic using each of the roadways is composed of substantially the same vehicle trips, such that the combined number of individual vehicle trips utilizing all of the roadways would result in an AADT of 400 or less.

E. Although a roadway may be considered to have a "limited use" in accordance with subsection D of this section, the Emergency Preparedness Plan for the low hazard impounding structure shall clearly outline a reliable and timely approach for notification of the proper local emergency services by the dam owner regarding the hazards of continued use of the road during an emergency condition.

4VAC50-20-52. Incremental damage analysis.

A. When appropriate, the spillway design flood requirement may be reduced by the board in accordance with this section. The proposed potential hazard classification for an impounding structure may be lowered based on the results of an incremental damage analysis utilizing one of the following methodologies:

1. Section III of the United States Department of Interior, Bureau of Reclamation's ACER Technical Memorandum No. 11, 1988. An impact shall be deemed to occur where there are one or more lives in jeopardy as a result of a dam failure; or

2. An approach to determining hazard classification found in any document that is on the list of acceptable references set out in 4VAC50-20-320. The owner's engineer shall reference the methodology utilized in the submittal to the department.

B. The owner's engineer may proceed with an incremental damage analysis. The proposed spillway design flood for the impounding structure may be lowered based on the results of an incremental damage analysis. Once the owner's engineer has determined the required spillway design flood through application of Table 1, further analysis may be performed to evaluate the limiting flood condition for incremental damages. Site-specific conditions should be recognized and considered. This analysis may be used to lower the spillway design flood. In no situation shall the allowable reduced level be less than the level at which the incremental increase in water surface elevation downstream due to failure of an impounding structure is no longer considered to present an additional downstream threat. This engineering analysis will need to present water surface elevations at each structure that may be impacted downstream of the dam. An additional downstream threat to persons or property is presumed to exist when water depths exceed two feet or when the product of water depth (in feet) and flow velocity (in feet per second) is greater than seven.

C. The spillway design flood shall also not be reduced below the minimum threshold values as determined by Table 1.

D. C. The proposed potential hazard classification for the impounding structure and the required spillway design flood shall be subject to reclassification by the board as necessary to reflect the incremental damage assessment, changed conditions at the impounding structure, and changed conditions in the dam break inundation zone.

4VAC50-20-54. Dam break inundation zone mapping.

A. Dam break inundation zone maps and analyses shall be provided to the department, except as provided for in 4VAC50-20-51, to meet the requirements set out in Hazard Potential Classifications of Impounding Structures (4VAC50-20-40) 4VAC50-20-40, Emergency Action Plan for High and Significant Potential Hazard Impounding Structures (4VAC50-20-175) 4VAC50-20-175, and Emergency Preparedness for Low Hazard Potential Impounding Structures (4VAC50-20-177) 4VAC50-20-177, as applicable. In accordance with subsection G of this section, a simplified dam break inundation zone map and analysis may be completed by the department and shall be provided to the impounding structure's owner to assist such owner in complying with the requirements of this chapter. All analyses shall be completed in accordance with 4VAC50-20-20 D.

B. The location of the end of the inundation mapping should be indicated where the water surface elevation of the dam break inundation zone and the water surface elevation of the spillway design flood during an impounding structure nonfailure event converge to within one foot of each other. The inundation maps shall be supplemented with water surface profiles showing the peak water surface elevation prior to failure and the peak water surface elevation after failure.

C. All inundation zone map(s), except those utilized in meeting the requirements of Emergency Preparedness for Low Hazard Potential Impounding Structures (4VAC50-20-177), shall be signed and sealed by a licensed professional engineer.

D. Present and planned land-use for which a development plan has been officially approved by the locality in the dam break inundation zones downstream from the impounding structure shall be considered in determining the classification.

E. For determining the hazard potential classification, an analysis including, but not limited to, those hazards created by flood and nonflood dam failures shall be considered. At a minimum, of the following shall be provided to the department:

1. A sunny day dam break analysis utilizing the volume retained at the normal or typical water surface elevation of the impounding structure;

2. A dam break analysis utilizing the spillway design flood with a dam failure;

3. An analysis utilizing the spillway design flood without a dam failure; and

4. For the purposes of future growth planning, a A dam break analysis utilizing the probable maximum flood with a dam failure.

E. To meet the requirements of Emergency Preparedness set out in 4VAC50-20-177, all Low Hazard Potential impounding structures shall provide a simple map, acceptable to the department, demonstrating the general inundation that would result from a dam failure. Such maps do not require preparation by a professional licensed engineer, however, it is preferred that the maps be prepared by a licensed professional engineer.

F. To meet the Emergency Action Plan requirements set out in 4VAC50-20-175 and the Emergency Preparedness Plan requirements set out in 4VAC50-20-177, all owners of High and Significant Hazard Potential impounding structures shall provide dam break inundation zone map(s) representing the impacts that would occur with both a sunny day dam failure and a spillway design flood probable maximum flood with a dam failure.

1. The map(s) shall be developed at a scale sufficient to graphically display downstream inhabited areas and structures, roads, public utilities that may be affected, and other pertinent structures within the identified inundation area. In coordination with the local organization for emergency management, a list of downstream inundation zone property owners and occupants, including telephone numbers may be plotted on the map or may be provided with the map for reference during an emergency.

2. Each map shall include the following statement: "The information contained in this map is prepared for use in notification of downstream property owners by emergency management personnel."

Should the department prepare a dam break inundation zone map and analysis in response to a request received pursuant to 4VAC50-20-40 C, the owner shall utilize this map to prepare a plan in accordance with this subsection.

G. Upon receipt of a written request in accordance with 4VAC50-20-40 C and receipt of a payment in accordance with 4VAC50-20-395, the department shall conduct a simplified dam break inundation zone analysis. In conducting the analysis, a model acceptable to the department shall be utilized. The analysis shall result in maps produced as Geographic Information System shape files for viewing and analyzing and shall meet the other analysis criteria of this section.

Upon completion of the analysis, the department shall issue a letter to the owner communicating the results of the analysis including the dam break inundation zone map, stipulating the department's finding regarding hazard potential classification based on the information available to the department, and explaining what the owner needs to do procedurally with this information to be compliant with the requirements of the Dam Safety Act (§ 10.1-604 et seq.) and this chapter.

4VAC50-20-101. General permit requirements for low hazard potential impounding structures.

Any impounding structure owner whose registration statement is approved by the board will receive the following permit and shall comply with the requirements in it. If the failure of a low hazard potential impounding structure is not expected to cause loss of human life or economic damage to any property except property owned by the owner, the owner may follow the special criteria established for certain low hazard impounding structures in accordance with 4VAC50-20-51 in lieu of coverage under the general permit.

General Permit No.: Dam Safety 1
Effective Date: (Date of Issuance of Coverage)
Expiration Date: (6 years following Date of Issuance of Coverage)
GENERAL PERMIT FOR OPERATION OF A LOW HAZARD POTENTIAL IMPOUNDING STRUCTURE

In compliance with the provisions of the Dam Safety Act and attendant regulations, owners of an impounding structure covered by this permit are authorized to operate and maintain a low hazard potential impounding structure. The owner shall be subject to the following requirements as set forth herein.

1. The spillway design of the owner's impounding structure shall be able to safely pass a 100-year flood. When appropriate, the spillway design flood requirement may be further reduced to the 50-year flood in accordance with an incremental damage analysis conducted by the owner's engineer.

2. The owner shall develop and maintain an emergency preparedness plan in accordance with 4VAC50-20-177. The owner shall update and resubmit the emergency preparedness plan immediately upon becoming aware of necessary changes to keep the plan workable.

3. The owner shall perform an annual inspection of the impounding structure. The owner shall maintain such records and make them available to the department upon request. The department also shall conduct inspections as necessary in accordance with 4VAC50-20-180.

4. The owner shall ensure that the impounding structure is properly and safely maintained and operated and shall have the following documents available for inspection upon request of the department:

a. An operating plan and schedule including narrative on the operation of control gates and spillways and the impoundment drain;

b. For earthen embankment impounding structures, a maintenance plan and schedule for the embankment, principal spillway, emergency spillway, low-level outlet, impoundment area, downstream channel, and staff gages; and

c. For concrete impounding structures, a maintenance plan and schedule for the upstream face, downstream face, crest of dam, galleries, tunnels, abutments, spillways, gates and outlets, and staff gages.

Impounding structure owners shall not permit growth of trees and other woody vegetation and shall remove any such vegetation from the slopes and crest of embankments and the emergency spillway area, and within a distance of 25 feet from the toe of the embankment and abutments of the dam.

5. The owner shall file a dam break inundation zone map developed in accordance with 4VAC50-20-54 with the department and with the offices with plat and plan approval authority or zoning responsibilities as designated by the locality for each locality in which the dam break inundation zone resides.

6. The owner shall notify the department immediately of any change in circumstances that would cause the impounding structure to no longer qualify for coverage under the general permit. In the event of a failure or an imminent failure of the impounding structure, the owner shall immediately notify the local emergency services coordinator, the Virginia Department of Emergency Management, and the department. The department shall take actions in accordance with § 10.1-608 or 10.1-609 of the Code of Virginia, depending on the degree of hazard and the imminence of failure caused by the unsafe condition.

4VAC50-20-102. Registering for coverage under the general permit for low hazard potential impounding structures.

A. Pursuant to § 10.1-605.3, an impounding structure owner may seek general permit coverage from the board for a low hazard potential impounding structure in lieu of obtaining a Low Hazard Potential Regular Operation and Maintenance Certificate in accordance with 4VAC50-20-105 or a Conditional Operation and Maintenance Certificate for Low Hazard Potential impounding structures in accordance with 4VAC50-20-150.

B. An owner shall submit a complete and accurate registration statement in accordance with the requirements of this section prior to the issuance of coverage under the general permit. A complete registration statement shall include the following:

1. The name and address of the owner;

2. The location of the impounding structure;

3. The height of the impounding structure;

4. The volume of water impounded;

5. An Emergency Preparedness Plan prepared in accordance with 4VAC50-20-101;

6. The applicable fee for the processing of registration statements as set out in 4VAC50-20-375;

7. A dam break inundation zone map completed in accordance with 4VAC50-20-54 and evidence that such map has been filed with the offices with plat and plan approval authority or zoning responsibilities as designated by the locality for each locality in which the dam break inundation zone resides; and

8. A certification from the owner that the impounding structure (i) is classified as low hazard pursuant to a determination by the department or the owner's professional engineer in accordance with § 10.1-604.1 and this chapter; (ii) is, to the best of his knowledge, properly and safely constructed and currently has no observable deficiencies; and (iii) shall be maintained and operated in accordance with the provisions of the general permit.

4VAC50-20-103. Transitioning from regular or conditional certificates to general permit coverage for low hazard potential impounding structures.

A. Holders of a regular certificate to operate a low hazard potential impounding structure shall be eligible for general permit coverage upon the expiration of their regular certificate. In lieu of a regular certificate renewal, registration coverage materials pursuant to 4VAC50-20-102 shall be submitted to the department 90 days prior to the expiration of the regular certificate.

B. Holders of a conditional certificate to operate a low hazard potential impounding structure shall be eligible for general permit coverage upon satisfying the registration requirements for a general permit pursuant to 4VAC50-20-102.

4VAC50-20-104. Maintaining general permit coverage for low hazard potential impounding structures.

Provided that an impounding structure's hazard potential classification does not change, an owner's coverage under the general permit shall be for a six-year term after which time the owner shall reapply for coverage by filing a new registration statement and paying the necessary fee. No inspection of the impounding structure by a licensed professional engineer shall be required if the owner certifies at the time of general permit coverage renewal that conditions at the impounding structure and downstream are unchanged. If such certification is made, the owner is not required to submit an updated dam break inundation zone map.

4VAC50-20-177. Emergency Preparedness Plan for Low Hazard impounding structures.

Low Hazard impounding structures shall provide information for emergency preparedness to the department, the local organization for emergency management and the Virginia Department of Emergency Management. A form for the submission is available from the department (Emergency Preparedness Plan for Low Hazard Virginia Regulated Impounding Structures). The information shall include, but not be limited, to the following:

1. Name of and location information for the impounding structure, inventory number, including city or county, and latitude, and longitude;

2. Owner's name, mailing address, Name of owner and operator and associated contact information including residential and business telephone numbers, and other means of communication. Contact information shall provide for 24-hour telephone contact capability;

3. Impounding structure operator's name, mailing address, residential and business telephone numbers, and other means of communication. Contact information shall provide for 24-hour telephone contact capability Contact information for relevant emergency responders including the following:

a. Local dispatch center or centers governing the impounding structure's dam break inundation zone; and

b. City or county emergency services coordinator's name or names;

4. Rainfall and staff gage observer's name, mailing address, residential and business telephone numbers, and other means of communication. Contact information shall provide for 24-hour telephone contact capability Procedures for notifying downstream property owners or occupants potentially impacted by the impounding structure's failure;

5. Contact information for alternate operator and alternate rainfall and staff gage observer, if applicable; A dam break inundation zone map completed in accordance with 4VAC50-20-54 and evidence that:

a. Such map has been filed with the offices with plat and plan approval authority or zoning responsibilities as designated by the locality for each locality in which the dam break inundation zone resides; and

b. Required copies of such plan have been submitted to the local organization for emergency management and the Virginia Department of Emergency Management; and

6. Contact information for the local dispatch center nearest impounding structure including address and 24-hour telephone number;

7. City or county emergency services coordinator's name, mailing address, residential and business telephone numbers, and other means of communication;

8. A procedure and the responsible parties for notifying to the extent possible any known local occupants, owners, or lessees of downstream properties potentially impacted by the impounding structure's failure;

9. A discussion of the procedures for timely and reliable detection, evaluation, and classification of emergency situations considered to be relevant to the project setting and impounding features. Each relevant emergency situation is to be documented to provide an appropriate course of action based on the urgency of the situation;

10. A simple dam break inundation map acceptable to the director, demonstrating the general inundation that would result from an impounding structure failure. Such maps required pursuant to this section do not require preparation by a professional licensed engineer; however, maps prepared by a licensed professional engineer are preferred;

11. Identification of public roads downstream noting the highway number and distance below the impounding structure. If roads exist, contact information for the resident Virginia Department of Transportation engineer or city or county engineer including address and 24-hour telephone numbers;

12. Amount of rainfall that will initiate a Stage II Condition in inches per six hours, inches per 12 hours, and inches per 24 hours and a Stage III Condition in inches per six hours, inches per 12 hours, and inches per 24 hours;

13. Amount of flow in the emergency spillway that will initiate a Stage II Condition in feet (depth of flow) and a Stage III Condition in feet (depth of flow);

14. Staff gage location and description; the frequency of observations by the rainfall or staff gage observer under a Stage I Condition, and Stage II Condition, and a Stage III Condition; and a clear description of an access route and means of travel during flood conditions to the impounding structure;

15. Evacuation procedures including notification, monitoring, evacuation, and reporting processes and responsibilities;

16. Evidence that the required copies of such plan have been submitted to the local organization for emergency management and the Virginia Department of Emergency Management; and

17. 6. Certification of the accuracy of the plan by the owner.

4VAC50-20-195. Judicial review.

Any owner aggrieved by a decision of the director, department, or board regarding the owner's impounding structure shall have the right to judicial review of the final decision pursuant to the provisions of the Administrative Process Act (§ 2.2-4000 et seq. of the Code of Virginia).

4VAC50-20-200. Enforcement.

The provisions of this chapter may be enforced by the board, the director, or both in any manner consistent with the provisions of the Dam Safety Act (§ 10.1-604 et seq. of the Code of Virginia). Failure to comply with the provisions of the general permit issued in accordance with 4VAC50-20-103 may result in enforcement actions, including penalties assessed in accordance with §§ 10.1-613.1 and 10.1-613.2.

Part VI
Fees

4VAC50-20-340. Authority to establish fees.

Under § 10.1-613.5 of the Code of Virginia, the board is authorized to establish and collect application fees to be used for the administration of the dam safety program, administrative review, certifications, and the repair and maintenance of impounding structures including actions taken in accordance with §§ 10.1-608, 10.1-609, and 10.1-613 of the Code of Virginia. The fees will be deposited into the Dam Safety, Flood Prevention and Protection Assistance Administrative Fund.

4VAC50-20-375. Fee for coverage under the general permit for low hazard impounding structures.

The fee for processing registration statements from impounding structure owners seeking to obtain coverage under the general permit for low hazard impounding structures shall be $300.

4VAC50-20-395. Simplified dam break inundation zone analysis fee.

Pursuant to authority provided in § 10.1-604.1 A 1 and in accordance with 4VAC50-20-40 C, when the department receives a request from the owner of a dam to conduct a simplified dam break inundation zone analysis, the owner shall submit a fee of $2,000 prior to the department conducting such analysis. The fee shall be submitted in accordance with 4VAC50-20-350 B and C as applicable. The fee shall be deposited into the Dam Safety Administrative Fund to be used to cover the partial cost of such analysis. Once the analysis has commenced, no analysis fee remitted to the department shall be subject to refund.

If the department attains additional efficiencies in its analysis process, the department is authorized to reduce this fee to a level commensurate with the costs.

DOCUMENTS INCORPORATED BY REFERENCE (4VAC50-20)

ACER Technical Memorandum No. 11, Downstream Hazard Classification Guidelines, December 1988, U.S. Department of the Interior, Bureau of Reclamation.

Trip Generation, 8th Ed., 2008, Institute of Transportation Engineers, 1627 Eye Street, NW, Suite 600, Washington, DC 20006.