1. Requirements to remove all woody vegetation from the dam and from within 25' of the dam - this requirement could be relaxed for existing dams. I agree with this requirement for the dam crest and slopes. But extending 25 feet from the toe could be relaxed for existing dams to lets say 10 ft.

2. Defining the dam height - the existing definion of hydraulic height of a dam sometimes not quite applicable. For example, a 10 ft tall dam constructed on top of a 10H:1V fill slope. The height of the foundation fill slope from the dam toe to the nearest stream is about 100 ft. According to the existing definition, the hydraulic height of the dam is 110 ft, but in reality it is only 10 ft tall.

Thanks

Shaikh Rahman
Dominion Energy

 We have a 22 achre lake that contained approxmately 144 achre feet of water when the lake was built in 1989.    The lake has 7 property owners on the lake.  The lake was originally catagortized, low hazzard.  Several years  ago the hazzard classification was changed to high, although no changes to the lake had occured. 

Our concern is that our small lake is in the same catagory as the largest lakes in the state. There are no occupied dwellings in the flood plane, however on a sunny day breach the state estimates, based on the original capacity, that there will be several inches of water across US-17, approxmately 1 mile downstream.  

We would like to see the state modify the regulations to recognize the difference in the magatude of property damage and/or loss of life.  Given the significant differences in the sizes of small lakes like ours and the larger lakes, to have the same classsifications is unecessarily onerous on small dam owners and dilutes the state's ability to adequately regulate and monitor the dams that are truly high risk. There are at least two potential solutions:

1.  Add additional catagories within the high hazzard classification that realistically take in to account the risk to property and life. 

2.  Add additional dam classifications, beyond the present three taking into account the size of the lakes and their obvious differences in potential risks to loss of life and/of property damage.

These changes would allow the state agencies to concentrate on the dams that truly high risk.     

There have been differing interpretations as to the applicability of 4VAC50-20-80, Alterations Permits, to subsurface drilling at embankment dams.  It is recognized that subsurface drilling could potentially affect the structural integrity of an impounding structure, and it is prudent to ensure such work is completed in a manner that minimizes risk to the impounding structure.  However, the Alteration Permit and design report process detailed in 4VAC50-20-80 includes requirements that are not relevant to a subsurface investigation while also falling short of ensuring appropriate qualifications of the drilling team and thorough planning of the drilling process.  The State should consider adopting a new written policy including a succinct and streamlined permit for subsurface investigations at dams.  This policy should also include minimum qualifications for drilling contractors.  This drilling permit would reduce the economic burden of addressing irrelevant requirements in 4VAC50-20-80 while improving the protection of public safety.  A similar program was introduced to FERC-regulated impounding structures in 2017.

There have been differing interpretations as to whether an Alteration Permit expires and must be extended during an on-going alteration project.  In 4VAC50-20-80, Alterations Permits, Paragraph F, states: “The Alteration Permit shall be valid for the construction sequence with milestones specified in the approved Alteration Permit Application.”  However, Paragraph G and issued Dam Safety Alteration Permits refer to a specific timeframe in which the work must commence.  One interpretation has been that as long as construction work has commenced within the timeframe specified in the issued Alteration Permit, then construction may continue after the specified timeframe has passed, and there is no action required by the owner, engineer, or Regional Engineer.  A different interpretation has been that the timeframe assigned in the Alteration Permit is based on the construction sequence and milestones specified in the Alteration Permit Application, and if the actual construction schedule extends beyond the Alteration Permit timeframe, then a new Alteration Permit should be issued to extend the permit timeframe.  Since alteration of an impounding structure is a significant activity that presents risks to the public and infrastructure, the State should consider requiring that an Alteration Permit be effective throughout the duration of construction and completion of all closeout activities specified in 4VAC50-20-80.  The State should require the impounding structure owner to submit a letter describing the changes to the construction sequence and milestones that necessitate an Alteration Permit extension in order to request a new Alteration Permit.  This request would not require any fees or significant effort, and the extended Alteration Permit would provide reassurance to the public, owner, and contractor that the State has approved of the on-going work at the impounding structure.

The current regulations state that specific inspections are to be performed by a licensed professional engineer, such as annual inspections, inspections during construction, and inspections after overtopping or emergency spillway damage.  However, the qualifications of the licensed professional engineer are not specified in 4VAC50-20.  The State should consider adding guidance or regulations regarding professional engineer qualifications for dam safety inspections, such as a minimum number of cumulative years in dam engineering.  Federal agencies, such as FERC, impose similar requirements for dam inspectors.

Section 4VAC50-20-45, Hazard Potential Classifications Based on Low Volume Roadways, Paragraph D, describes the applying the term “limited use” and assigning a low hazard potential classification despite the presence of the roadway.  The second sentence refers to roadways “…located either across or below an impounding structure…”  The phrase “below an impounding structure” is not used elsewhere in the regulations.  Please consider clarifying if the regulations are referring to all roads downstream of the impounding structure, or if “below an impounding structure” refers to a roadway located on or adjacent to the toe of the impounding structure.

Clover Dam in Albemarle County is an example of a very small pond (8 acres or less with silting-in), with very little development downstream (one residence, not in the flood plain, which would at most suffer a flooded basement in the worst-case scenario), which has been categorized as a significant hazard.

The regulations do not seem to take into account the situation where flooding on a low-lying secondary roadway downstream from a dam occurs regularly with ordinary heavy rainstorms.  The circumstance of an overtopped dam would not change that situation.  The neighborhood faces this situation all the time.  There is an alternate “back way” into the neighborhood that is used when this happens.

We recommend that more classifications or additional exemption criteria to the current classifications could more fairly address the situation of small dams/small ponds in low-density areas with one small secondary roadway and ample downstream farm land to absorb run-off.  It should be permissible to augment the standard interpretation of regulations with an on-the-ground reality check that might reveal a less dramatic risk than is currently assigned.

Furthermore, the situation of Clover Dam illustrates how the current regulations discourage the implementation of safety improvements by demanding repetitive engineering inspections, analyses, and filings which are costly and deplete the resources of a small neighborhood, leaving little ability to pay for upgrades.

The regulations do not consider that older dams (vintage 1960s) may have been approved by county permitting authorities without adequate supervision or engineering rigor, leaving current residents unfairly facing enormous bills to bring these dams into compliance without state or county assistance.  The regulations should be amended to provide relief and consideration to homeowners faced with correcting deficiencies that exist due to inadequate government oversight at the time of construction.

Finally, the regulations should be amended to allow for gradual improvements over time to more realistically address the ability of a small neighborhood to pay for massive construction projects.

In section 4VAC50-20-50.C, the probable maximum flood (PMF) is defined as the "flood expected that might be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in the region". The key phrases in this statement are "most severe" and "reasonably possible", and these phrases only occur in the regulations for the definition of the PMF flood. However, in the guidance documents published by DCR, DCR has expanded the use of these phrases to state that the PEOR is to ensure "the worst case hydrologic/hydraulic scenarios are being utilized". The expansion of the term "worst case" is highly subjective, and puts an undue burden on the PEOR to try to prove to the Regional Engineer that this standard has been achieved. Without a clear definition of "worst case", there are an infinite number of scenarios that could be generated and we do not believe that this is a productive or necessary exercise. The intent of the regulations was to set a standard for dam owners that puts public safety as the number one goal, but also considers the responsibility and financial burden of the dam owner.

We request that if the standard is "worst case hydrologic/hydraulic scenario", that this be clearly stated and defined in the regulations. In addition, we believe the "worst case scenario" should be stipulated as something that is "reasonably possible" in the state of Virginia.   We believe "worst case" should be defined as the combination of hydrologic/hydraulic modeling that impacts the most properties and has the highest hazard classification. The PEOR should describe why the modeling submitted is the "worst case" qualitatively.  We believe "reasonably possible" should be defined as the hydrologic/hydraulic that utilizes standard engineering practice for determining watershed hydrology and hydraulics. Again, the PEOR should describe why the modeling is "reasonably possible" qualitatively.

When changes are made to regulations or to the DCR published guidance documents, we request that the revised document be published with a strike-through for deleted text and highlight/bold for added text. This helps users understand what exactly has changed from version to version.

Governor Northam’s Executive Order Fourteen (EO14) states that “regulations shall be clearly written and easily understandable.”  As written, 4VAC50-20 is not clearly written and easily understandable in so much as DCR’s implementation relies upon publication of guidance documents that are outside the scope of law and regulation.  The regulations should be modified under the Administrative Process Act to incorporate certain decisions currently “required” by guidance.  The establishment of the requirements via guidance does not provide sufficient awareness and ability to comment on the impacts of the guidance.  The incorporation of the guidance documents via regulatory process will provide the industry the ability to provide professional review and comment and allow DCR the ability to receive comments on the impacts on small businesses.

Per Executive Order Fourteen (EO14), “Regulatory development shall be based on the best reasonably available and reliable scientific, economic, and other information concerning the need for, and consequences of, the intended regulation. Agencies shall specifically cite the best reasonably available and reliable scientific, economic, or statistical data as well as any other information in support of regulatory proposals.” The internal development of guidance documents does not provide the opportunity for the professional community to offer DCR reasonably available alternatives for consideration.

DCR requirements regarding roadways existing on top of dam embankments (4VAC50-20-45 and Guidance Document on Roadways on or Below Impounding Structures) appear to be both arbitrary and contradictory to federal and state roadway design criteria.  There are few, if any, roadways in Virginia designed to convey large storm events (PMF events) without overtopping, without the risk of failure during large storm events, without the risk of loss of life, or without the risk of economic damage.  Roadways on top of dams should be excluded from the Virginia impounding structure hazard potential classification process.

DCR regulations allow the use of ACER-11 to determine whether roads and property have been impacted in 4VAC50-20-45 and 4VAC50-20-52(A), but do not allow ACER-11 to be used to determine whether roads and property have been impacted in 4VAC50-20-52(B).  ACER-11 should be an allowable methodology to determine whether roads and property have been impacted in 4VAC50-20-52(B).