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Required Physical Features of a Creek

A creek must include all of the following three features: (1) hydrologic connectivity, (2) presence of channel form and (3) topographic position. A creek begins at the first point at which these features are met.

  • 1. Hydrologic Connectivity: The creek is part of a contiguous waterway. It is hydrologically connected to a waterway above and below the site or is connected to a spring, headwaters, lake, the Estuary, or the Bay.

    Clarification Criteria: The following clarify specific conditions that must be present in order to satisfy the hydrologic connectivity criteria. If any of the following conditions are present, the hydrological connectivity requirement is generally met:

    • Creek headwaters, springs, storm drain culverts, underground seepage, or groundwater flow are considered connectivity. Sections above and/or below this connectivity are creeks if they meet the other required features (i.e., a creek flowing through a culvert is a creek both above and below the culvert.)
    • Creeks may be connected across or over manmade improvements such as roads. When flowing across or over such improvements within the public right-of-way, other than creek channel improvements, it is not considered a creek. Sections above and/or below this connectivity are creeks if they meet the other required features.
  • 2. Channel Form: There is a channel, including a bed, bank, and features that indicate actual or potential sediment movement.

    Clarification Criteria: The following clarify specific conditions that must be present in order to satisfy the hydrologic connectivity criteria. If any of the following conditions are present, the hydrological connectivity requirement is generally met:

    • Creek channels may be natural, altered or engineered.
    • Creek channels begin at the point of bed and bank initiation.
    • Springs are considered the start of a creek if located uphill from creek initiation.
    • A creek channel must have enough flow under present-day conditions to maintain channel form and to move sediment. A non-engineered creek channel bed and bank are created and maintained by erosion and sedimentation, thus the presence of a channel with bed and bank is itself evidence of sufficient flow. Flow volume or timing are not criteria for creek determination.
    • Scour, sedimentation, sediment sorting, undercut banks and/or other erosion, deposition or transport features are signs of sediment movement.
    • Engineered or altered channels are partially or wholly made of earth, concrete, rip rap or other materials. The hardened nature of these channel bed and banks, and a lack of available sediment along the channel reach, may prevent signs of sediment movement or scour. Such channels need not have explicit evidence of sediment transport.
    • If a creek is connected underground and the area overlying this underground connection is considered a wetland using the Army Corps of Engineers wetland delineation criteria, this portion is a creek despite possibly lacking creek channel form.
    • If a creek is underground due to being filled without appropriate permits from all applicable regulatory agencies (federal, state and local) or due to a landslide, it is considered a creek.
  • 3. Topographic Position: Creeks must occupy a specific topographic position.

    Clarification Criteria: The following clarify specific conditions that must be present in order to satisfy the hydrologic connectivity criteria. If any of the following conditions are present, the hydrological connectivity requirement is generally met:

    • Micro-topography such as a 'U' shape or 'V' shape channel typically located at the low point of a macro-topographic feature.
    • Macro-topography consists of bowl, 'U', or 'V' shaped topography with high points draining to a valley or ravine as part of a large drainage network leading to large creeks, lakes, the Estuary and/or the Bay.
    • Flatland macro-topography may consist of shallow bowl or 'U' shaped topography. Generally these creeks flow from the hills toward the Estuary and Bay following the slope of the land.
    • Creek topography can be indicated on a topography map by a 'U' or 'V' shape pointed in the uphill direction.

Indicator Features

To help with screening and identification in the field a creek may also have the following features (the absence of these features does NOT mean there is no creek):

  • A riparian corridor-a corridor of relatively denser vegetation roughly parallel to the creek channel, or soil conditions that would support native riparian vegetation. Riparian vegetation is sometimes missing due to landscaping or vegetation removal practices, landslide, or fire.
  • Bed with material that differs from the surrounding geologic material (i.e. more rocky or gravelly, little or no vegetation, sorted by size).
  • Man-made structures common to waterways, for example bank retaining walls, trash racks, culverts, inlets, rip rap, road bends, etc.
  • Tidal or backwater influence, and/or nutrient or resource exchange with the Estuary or the Bay.
  • Wetland vegetation.

Creek Permitting Guide Illustration
Exclusions
The definition of creeks generally excludes the following conditions or features, although these conditions may represent hydrologic connectivity for an upstream and/or downstream creek:

  • The following structures (while the structures themselves are not considered creeks, the presence of these structures does not preclude the determination of a creek):
    • Improved roads
    • Rain gutter gullies fed only by the rain gutters of a building or other roof runoff
    • Curb/gutter, pipes, culverts, fully enclosed storm sewers, inlets, and catch basins
  • Biofiltration swales, faux creeks, detention basins, mosquito ditches or stormwater attenuation features that were not intended to function as a creek or wetland, and/or were not installed as mitigation for creek or wetland disturbance.

Seminal Court Case (Locklin v. City of Lafayette (1994) 7 Cal. 4th 327)
The Locklin court case has provided additional guidance in clarifying the definition of a "Creek" in Oakland and is consistent with current City policy and practice. The Locklin definition of a "natural watercourse" is similar to Oakland's definition of a creek.

A Natural Watercourse (in Oakland, a "Creek"):
"Is a channel with defined bed and banks made and habitually used by water passing down as a collected body or stream in those seasons of the year and at those times when the streams in the region are accustomed to flow. It is wholly different from a swale, hollow or depression through which may pass surface waters in time of storm not collected into a defined stream. A canyon or ravine through which surface water runoff customarily flows in rainy seasons is a natural watercourse. Alterations to a natural watercourse, such as the construction of conduits or other improvements in the bed of the stream, do not affect its status as a natural watercourse. A natural watercourse includes all channels through which, in the existing condition of the country, the water naturally flows and may include new channels created in the course of urban development through which waters presently flow. Once surface waters have become part of a stream in a watercourse, they are no longer recognized as surface waters." (page 345)

General Creek Functional Guidelines
The following are typical functions of creeks in Oakland. These functions act as general guidelines to be used in creek determinations:

  • Carries fresh or estuarine water either seasonally or year round
  • Supports native riparian, wetland, and/or aquatic habitats
  • Maintains channel form (which includes bed and bank)
  • Provides flood control and storm drainage
  • Removes pollutants and improves water quality
  • Transports, stores, and/or sorts sediment
  • Maintains stable flow regime, including water transport, detention, and/or infiltration
  • Provides community and aesthetic value