One result of the politically-charged decision was the creation of the Friends of Accotink Creek. Water in the disputed stream segments ultimately flowed into Accotink Creek. All segments downstream of a perennial segment in Fairfax County will have even more water, rather than revert to intermittent flow. That illogical pattern demonstrates how human judgment was a factor in the classification process. Further downstream the tributary crossed into the Town of Vienna, and the town classified the stream within its boundaries as intermittent. Removal of the Resource Protection Area buffers allowed the landowner to double the number of houses permitted on the 12-acre "Wedderburn" parcel, which was known locally as Midgetville due to an urban legend that retired circus workers lived there.įairfax County continued to categorize the tributary as perennial, downstream of the stormwater management pond. However, neighbors objected to the reclassification.
EPHEMERAL STREAM INSTALL
The developer proposed to install a stormwater management pond downstream of the project, which would also mitigate the impacts of the construction of houses in the formerly-marshy area upstream. The Fairfax County Department of Public Works and Environmental Services reclassified the segment as intermittent. Photographs showing no water flow for three weeks in late summer were judged to be adequate data. She claimed that construction of houses on a formerly-marshy area upstream had reduced water flow.įairfax County used observational data to declassify streams from perennial to intermittent, a less complicated procedure than the 25-step assessment used to designate a stream as perennial. The landowner disputed Fairfax County's designation of the stream segment as perennial. The designation for a portion of a tributary of Buck Branch near the town of Vienna became controversial in 2004. Source: Fairfax County, Fairfax County Streams Mapping Project When intermittent stream segments are reclassified as perennial, expanded Resource Protection Areas affect plans of developers Plans of development submitted by developers had to recognize the stream buffer zones. When Prince William County completed a Perennial Flow Determination (PFD) and identified a perennial stream segment, it then completed a Preservation Area Site Assessment (PASA) study to define the exact boundaries of the Resource Protection Area. The larger jurisdictions, such as Fairfax County, conduct site-specific determinations when the US Geological Survey maps indicate the presence of an intermittent stream which may actually be perennial. When counties, cities, and towns must identify Resource Protection Areas and ensure buffers are protected when approving rezonings and site plans for development.Įphemeral stream channels are dry most of the time, and flow only during and right after precipitation events (rain/snow) The Chesapeake Bay Regulations call for landowners to preserve a buffer of natural vegetation along perennial streams, 100 feet wide on either side. The 84 jurisdictions affected by the Chesapeake Bay Preservation Act are required to designated Resource Protection Areas (RPAs) along perennial streams. Because of the sheer number of stream miles displayed on the topographic maps, little ground truthing was possible. Channels of ephemeral streams were not mapped, other than with topographic indicators. A dotted blue line was used to display the location of intermittent streams. The US Geological Survey (USGS) displays perennial streams on 1:24,000 scale maps with a solid blue line. Intermittent streams flow for portions of a year, when there is sufficient groundwater Groundwater is not a source of water for the stream. In many states, this term refers to streambeds that are located above the water table yearround and streams where Ephemeral: A stream that has flowing water only during or for a short duration after precipitation events in a typical year. Runoff from precipitation is a supplemental During dry periods, intermittent streams may not have flowing water. Intermittent: A stream that has flowing water during certain times of the year, when groundwater provides water for stream flow. Runoff from precipitation is a supplemental source of water for stream flow. Groundwater is the primary source of water for stream flow. The water table is located above the streambed for most of the year. Perennial: A stream that has flowing water year-round during a typical year. In 2014, a survey by the Association of State Wetland Managers used the following definitions: 1 Regulations differ, and are not applied consistently. Streams are classified by different jurisdiction in different ways. Ephemeral Streamsīroad Run is a perennial stream running through Prince William County
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