Field Procedures for Perennial Stream

The following criteria should be examined in the field on a site-by-site basis to determine whether a particular stream reach has perennial or intermittent stream flow.

1. STREAMFLOW

  • Presence or absence of flowing water dependent upon antecedent moisture conditions.

2. CHANNEL GEOMETRY

  • Perennial systems exhibit a defined and consistent geometric shape.
  • Channel parameters include bank height, channel width, bank slope, and channel slope.

3. STREAM BED SOILS

Perennial streams

  • Absence of characteristics associated with a fluctuating water table (i.e., iron redox-concentrations and oxidized rhizoshperes).
  • Sandy soils contain a relatively equal distribution of organics throughout the soil profile.
  • Presence of gravel and/or cobbles with little or no silts or clays associated with the surface soils.

Intermittent streams

  • Presence of characteristics associated with a fluctuating water table (i.e., iron redox concentrations and oxidized rhizospheres), particularly iron-redox concentrations.
  • Mineral soils with matrix and mottles of contrasting color, chroma variable, often > 1.
  • Organics not evenly distributed throughout the matrix of sandy soils and/or organic streaking evident in the surface horizon.
  • Presence of organic pan (i.e., accumulation of organic materials in bed layers) suggesting absence of flow during some period of the year.

4. VEGETATION

Perennial streams

  • In lower energy systems (i.e., bottomlands or areas situated just above tidal influence), presence of species with a submerged-aquatic or floating leaved-aquatic life history strategies.
  • In higher energy systems, a general absence of rooted vegetation.

Intermittent drainage system

  • Presence of annuals or emergent perennials that require exposure (no inundation) at some point during the growing season.

5. BENTHIC MACROINVERTEBRATES

  • Presence of species that have an aquatic life cycle of greater than one year.
  • Species identification generally completed by a qualified aquatic ecologist.

6. VERTEBRATES

  • In general, the presence of fish.

7. OFFSITE RESOURCES

  • Discussions with long-term residents and local professionals
  • Personal communications with local professionals that include hydrologists, county agents, Natural Resource Conservation Service (NRCS) technicians, surveyors, foresters, and field engineers.
  • Review of aerial photographs.

RPA WETLAND DETERMINATIONS

Nontidal wetlands connected by surface flow and contiguous to tidal wetlands or water bodies with perennial flow are included as Resource Protection Area features. In order for these wetlands to be included as Resource Protection Area features, they must rely primarily on the tidal or perennial stream and/or waterbody to supply their main source of wetland hydrology. In making this determination, the question should be asked if this wetland would be present in this location if the tidal or perennial waterbody was removed from the landscape. If the wetland would cease to be present in this situation, it should be included as an RPA feature.


Engineering & Environmental

Public Works

Contact Information

Department of Public Works

Mailing Address:
County of Henrico, VA
P.O. Box 90775
Henrico, Virginia 23273-0775


Copyright 1996-2010 Henrico County 4301 East Parham Road, Henrico, VA 23228