DPWES Letters to Industry
Land Development Services
12055 Government Center Parkway
Fairfax, Virginia 22035
703-324-1720, TTY 711
January 11, 2007
New Plan Submission Requirements Related to Dams
This notice is to remind you of the requirements of the Virginia Dam Safety Act and to initiate a new procedure affecting construction and as-built plans that are submitted to the county for review.
All dams in Virginia are subject to the Virginia Dam Safety Act unless specifically excluded. As such, no person or entity shall construct, begin to construct, alter or begin to alter an impounding structure until the Virginia Soil and Water Conservation Board (VS&WCB) has issued a construction or alteration permit. A dam may be excluded from this requirement if it:
- is less than 6 feet in height;
- has a capacity less than 50 acre-feet and is less than 25 feet in height*;
- has a capacity of less than 15 acre-feet and is more than 25 feet in height;
- is used for primarily agricultural purposes and has a capacity** less than 100 acre-feet or height less than 25 feet (should use or ownership change, the dam may be subject to regulation);
- is owned or licensed by the Federal Government; or
- is operated for mining purposes under 45.1-222 or 45.1-225.1 of the Code of Virginia.
*In practice, the height of the dam is measured as the vertical distance from the original channel invert elevation to the top of the dam. The top of the dam is that point along the top of the embankment (not to include the emergency spillway) that has the lowest elevation. The figures below are schematic drawings that illustrate the dimensions used in determining appropriate heights.
**The capacity of a dam is defined as the volume capable of being impounded at the top of the dam.
Please refer to the Virginia Dam Safety Act of the Code of Virginia and the Virginia Impounding Structures Regulations (Dam Safety) established by the Virginia Soil and Water Conservation Board for the specific requirements. Information can be obtained from the Virginia Department of Conservation and Recreation, Division of Dam Safety and Floodplain Management. Note that these regulations include ongoing requirements that are in effect for the life of the structure.
To help ensure that these requirements are being met, from the date of this letter, please adhere to the following procedure:
- Indicate on the cover sheet of all construction plans submitted to the county for review that include an impoundment subject to these requirements, that the necessary construction or alteration permits shall be obtained from the VS&WCB prior to beginning work.
- As a condition of the county's final plan approval, it will be necessary for you to provide a copy of the approved VS&WCB permit to the Plan Control Section in Land Development Services.
- Indicate on all as-built plans that include an impoundment subject to these requirements, that the necessary permits were obtained and that the project adheres to the Virginia Impounding Structures Regulations (Dam Safety).
- To avoid confusion on dam height determinations, include on all construction and as-built drawings dimensional information including elevations for the dam such as that shown on these schematic drawings (PDF).
- Please coordinate the submission of your application for the required VS&WCB Operation and Maintenance Certificate with the Fairfax County Stormwater Planning Division (SWPD).
- As a condition of final bond release, it will be necessary for you to provide a copy of the VS&WCB Operation and Maintenance Certificate to SWPD.
Please refer to Section 6-1600 of the Fairfax County Public Facilities Manual for more information on the design and construction of impoundments.
If you have any questions, please contact Environmental and Site Review Division at 703-324-1720, TTY 711.