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Department of Environmental EngineeringChesterfield County Guidance for Site Specific Determinations of Perennial StreamsAreas of the County that are designated as Chesapeake Bay Preservation Areas (CBPAs) are categorized as either Resource Protection Areas (RPAs) or Resource Management Areas (RMAs) . RPAs are protected from most development because, left intact, they function to improve and protect water quality. RMAs are regulated to protect RPAs and water resources from degradation resulting from development and land disturbing activity. On November 23, 2004, the Chesterfield County Board of Supervisors adopted amendments to the Chesapeake Bay Preservation Ordinance. These amendments were developed to comply with changes to the State Chesapeake Bay Preservation Designation and Management Regulations that were adopted in 2001. One of the requirements of both the State Regulations and the Ordinance is to ensure that “a reliable, site-specific evaluation is conducted to determine whether water bodies on or adjacent to the development site have perennial flow…” The Ordinance further states that such evaluations are to be conducted or approved by The Water Quality Section as part of, or prior to, a zoning application, plan review process or in conjunction with the review of a water quality impact assessment for a development project. Chesterfield County Perennial Flow Determination ProcessPerennial stream determinations performed by an outside agent or consultant are confirmed ‘in-field’ by county staff after submittal. Determinations may also be done free of charge by county staff. Landowners must submit a “request” or “confirmation” form to the county depending on their situation. All perennial stream request or confirmation forms shall be submitted to:
All forms shall be submitted via United States Postal Service or hand delivery to the Department of Environmental Engineering. Request and confirmation forms require the address and GPIN of the property in question, and the signature of the Landowner. Forms submitted with the signature of an agent or consultant will not be accepted. Upon the acceptance of a request or confirmation, the project is given a number based on the order in which it was received. Determinations are generally completed in the order of receipt. It is the goal of this office to complete perennial flow determinations in a timely manner. Processing and field verification will usually take six to eight weeks depending on weather conditions and volume of work. In response to a request or confirmation, The Water Quality Section will mail a letter and map to the applicant and/or landowner indicating findings only. The findings-only letter is provided in lieu of a full report in order to provide a more rapid response time. If the requesting party would like more information as to how the final determination was made, they may contact the Water Quality Section at 748-1035. Methods for Site Specific DeterminationsPerennial Streams shall be identified using a scientifically valid system of in-field indicators as determined by the Director of Environmental Engineering. Acceptable methods include, but are not limited to, the most current version of The North Carolina Stream Identification method developed by the North Carolina Division of Water Quality and/or the perennial stream mapping protocol developed by Fairfax County (Virginia) Department of Public Works. Other site-specific methods may be used so long as they have been determined to be scientifically valid by the Virginia Department of Conservation and Recreation, Division of Chesapeake Bay Local Assistance and are acceptable to, and have been coordinated with the Director of Environmental Engineering. In field protocols and data sheets are available through the Department of Environmental Engineering or as downloaded documents from the links provided at the bottom of this page All site specific determinations should include a narrative describing how, when and where the observations were made, the weather conditions at the time the observations were made, and the study's final conclusion on whether the stream is perennial or intermittent. Additional information may be required depending on the method used. Specific requirements of approved methods are outlined in the sections Field Indicator Protocols and Documented Observation (Photographic Method) Professional disciplines required for making field determinations of stream perenniality will vary depending on the protocol or method used. Those using an ecologically based method should have an educational background, training and experience in stream ecology or the appropriate training and experience in the particular protocol employed. Field Indicator ProtocolsThe use of field indicator protocols entails the evaluation of observations made of stream geomorphology, hydrology and biology. The Virginia Department of Conservation and Recreation, Division of Chesapeake Bay Local Assistance has reviewed and found two field indicator protocols to be acceptable for making site-specific determinations. The first is a method developed by the North Carolina Division of Water Quality. The second is a modification of the North Carolina method developed by Fairfax County, Virginia. The North Carolina and Fairfax County protocols have both recorded a range of scores, Photographs may be used to help identify field conditions at the time the study was completed. The use of photographs to classify a stream as intermittent must follow the guidelines set forth under the section: Documented Observation Method (Photographic Method) Guidelines for Field Indicator ProtocolsStream flow determinations should be made at least 48 hours after the last known rainfall. Determinations must not be made without first walking up and down the full length of the channel. This initial examination allows the evaluator to study the nature of the channel, observe characteristics of the watershed and observe characteristics that indicate the source of water that may predominately or solely contribute to flow. As a general rule of thumb, several hundred feet (sometimes more) of channel should be examined to make determinations. Several stream reaches may need to be assessed in order to get an accurate representation of stream conditions. Reduced topography, which can result in fewer channel-forming features, can make scoring of stream geomorphology problematic in low gradient streams in flood plains or the Coastal Plain Region. In these areas, particular note and emphasis should be taken of in stream biology in order to determine if a stream is perennial or intermittent. A stream may be considered perennial if biological indicators that require water for entire life cycles are present (Fish, crayfish, amphibians, mussels or clams, or large, multi-year tadpoles or benthic macroinvertebrates). Data sheets for each stream reach assessed must be submitted to the Chesterfield County, Water Quality Section. Data sheets must include weather observations at the time the data was collected and may be supplemented by photographs of site conditions at each reach. (Note-Photographs of stream channels will not be accepted as evidence that a stream is intermittent unless the procedures outlined in the section Documented Observation Method (Photographic Method) are followed. Data sheets should be submitted to the county as closely as possible to the date the fieldwork was performed. The Water Quality Section may require additional fieldwork to be performed if it is deemed necessary. Those using the North Carolina or Fairfax field indicator protocol methods should have an educational background, training and experience in stream ecology or the appropriate training and experience in the particular protocol employed. Documented Observation Method (Photographic Method)Observations of stream flow shall be made in accordance with the following:
A second set of observations at the same photo points must be made no sooner than 7 and no later than 30 days after the original observations. The Weekly Palmer Drought Severity Index (PDSI) for the Virginia Eastern Piedmont Region at the National Weather Service Climate Prediction Center (NOAA et al) shall be used to determine the general hydrologic conditions at the time of observation. Chesterfield County may use or require additional meteorological data from local rain gauge stations or monitoring sites to evaluate general conditions. The weekly values can be found at: The Water Quality section tracks the Weekly PDSI and can provide data if needed. Photographic documentation of the absence of stream flow will not be accepted as definitive proof that a stream is intermittent if the weekly Palmer Drought Severity Index (PDSI) is –1.0 (abnormally dry/mild drought) or drier at any time during a period extending from 30 days prior to the date that the first set of observations are made through 30 days after the date when the second set of observations are made.
Observations shall be made at the true channel bottom, located below the movable bed material. Where the channel bed is armored, the presence of flow within the armoring layer must be checked. The Water Quality Section shall be advised prior to or within three days of completion of the first set of observations of the intent to submit photographic documentation of intermittent stream conditions. The Water Quality Section will coordinate a field review with the landowner or agent of the landowner for the second set of observations whenever possible. The Documented Observation Method (Photographic Method) shall include: The date, time, name of the observer and weather conditions at the time of observation, as well as photographs looking upstream and downstream documenting each observation. Photographs shall capture the various stream features (e.g. pools, riffles, and runs) along the stream. Photographs of the stream shall be taken close enough to see the channel bed and banks, shall show the channel bottom and any armoring materials and shall be unobstructed by vegetation. If a clear view cannot be obtained by relocating the point of observation, vegetation may be trimmed to obtain a clear view. Photographs of the channel shall include identifiable stationary landmarks in the field so that the point of observation can be verified at a later date if necessary. Identifiable landmarks include survey markers with identification, structural objects such as culverts or bridges, nearby buildings or unique natural features. Photographs must have a visible date stamp or certification by the observer of the date the photographs were taken. The submitted report for the Documented Observation Method must include:
Please direct questions on our process for perenniality determinations, the Water Quality Manager by email or, by phone, at 768-7435.
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