Chesapeake Bay Preservation Areas

Resource Protection Areas

Listed below is information about perennial streams and riparian buffers, both of which are features of Resource Protection Areas (RPAs).For more information on these and other requirements such as septic pump out, please consult Chesapeake Bay Preservation Act listing under Stormwater Guidance.

Perennial Stream Determinations

Section 9 VAC 25-830-50 of the Chesapeake Bay Preservation Area Designation and Regulations requires that local governments, as part of their plan-of-development review process or during their review of a Water Quality Impact Assessment ensure or confirm that (i) a reliable, site-specific evaluation is conducted to determine whether water bodies on or adjacent to the development site have perennial flow, and (ii) RPA boundaries are adjusted, as necessary, on the site, based on this evaluation of the site. Local governments may accomplish this by either conducting the site evaluations themselves or requiring the person applying to use or develop the site to conduct the evaluation and submit the required information for review.

The Commonwealth recognizes that there are a number of approaches to making evaluations of stream perennialty and will not mandate that any particular method be used exclusively. Guidance is available for making distinctions between intermittent and perennial streams. This guidance includes an in-the-field protocol, which will be based largely upon a preponderance of field evidence emphasizing the physical and biological characteristics of the stream channel. Three field indicator protocols, field tested in Fairfax County, VA., the State of North Carolina and James City County (including some surrounding upper Coastal Plain localities), are acceptable for making site-specific determinations. The protocols and field evaluation forms are:

The preferred time for making determinations as to whether a stream contains perennial flow is during the height of the local dry season, which in Virginia is usually between July and early September when normal weather conditions prevail. Thus, if the stream contains water at that time, it will likely contain water at all other times of the year. When it is not possible to survey streams in the dry season, additional corroborative evidence is often necessary. Current weather conditions should be noted since recent or overabundant rainfall can bias any decision. Preferably stream flow observations should not be within 48 hours after the last rainfall. In turn, drought conditions may cause perennial streams to temporarily run dry with water only standing in pools.

Climate Data: Knowledge of recent precipitation and seasonal climatic conditions is very important in corroborating information collected during field evaluations. The following are links to web sites for current and historic climatic data. Many daily newspapers also provide recent climatic data as well as seasonal information (i.e., month-to-date and year-to-date precipitation).

  • The National Weather Service in Wakefield, VA., includes current and historic data for Richmond, Norfolk, Salisbury, MD., and Elizabeth City, NC. Navigate to climate/local data to obtain daily, monthly and historical data. Monthly regional data is also available for a number of other areas in the state at this same web site.
  • Precipitation information can also be obtained from the National Weather Service Office in Sterling, VA, which provides recent and historic weather data for northern Virginia areas, Washington D.C., and Baltimore, MD.
  • National Centers for Environmental Information (formerly National Climatic Data Center) website may have a fee involved for accessing/obtaining data (may be free for some governmental entities).

Riparian Buffers

The Chesapeake Bay Preservation Act and regulations require that a vegetated buffer no less than than 100 feet wide be located adjacent to and landward of all tidal shores, tidal wetlands, non-tidal wetlands connected by surface flow and contiguous to tidal wetlands or along water bodies with perennial flow. These features, including the 100-foot buffer, comprise the Resource Protection Area (RPA), and serve a direct water quality function by removing excess sediment, nutrients, and potentially harmful or toxic substances from groundwater and surface water entering the Chesapeake Bay and its tributaries. Buffers also help to absorb periodic flood surges, and supply thermal protection, food, and cover to fish and other wildlife, stabilize stream-banks, and provide recreation and aesthetic values.

Generally, vegetation in the 100-foot buffer must be preserved on lots that include an RPA, and established where it does not exist. The regulations permit a property owner to modify the buffer by removing vegetation for several reasons:

  • To provide for reasonable sight lines
  • The construction of access paths
  • General woodlot management
  • Shoreline erosion control projects

Since the establishment of the Bay Act, local government staff members have requested guidance on how to interpret and implement the sections of the regulations that address buffer establishment, conservation, restoration, modification and mitigation.

The Riparian Buffers Modification and Mitigation Manual was adopted in September 2003. Created with support from the U.S. Forest Service, the document provides technical recommendations for the establishment of riparian buffers. It includes recommendations for specific changes to land use ordinances that may be adopted by the Tidewater local governments.

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Virginia Department of
Environmental Quality
P.O. Box 1105
Richmond, VA 23218
(804) 698-4000


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