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Hydraulic Engineering

Tables for FHWA-HIF-07-033

Table 1.1 Possible Geomorphic Responses and Impacts of a Stream Channel to an Undersized Culvert (adapted from Bates et al. 2006)
Geomorphic Response to Undersized Culvert
Downstream erosion of bed and banks
Downstream channel incision
Disconnected floodplains
Direct habitat loss and degradation
Upstream aggradation
Increased risk of debris clogging
Barrier to fish and aquatic organism passage
Table 2.3 Fish-Passage Design Criteria for Culvert Installations, Customary Units (Bates et al. 2003)
(Greater culvert lengths require lower velocity thresholds, while the increased swimming ability of larger fish (Adult Chinook, Coho, Sockeye and Steelhead) allows larger hydraulic drops and barrel velocities, but require a larger minimum depth.)
  Adult Trout >6 in. (150 mm) Adult Pink or Chum Salmon Adult Chinook, Coho, Sockeye or Steelhead
Culvert Length Maximum velocity (fps)
10 - 60 feet 4.0 5.0 6.0
60 - 100 feet 4.0 4.0 5.0
100 - 200 feet 3.0 3.0 4.0
Greater than 200 feet 2.0 2.0 3.0
  Minimum water depth (ft)
  0.8 0.8 1.0
  Maximum hydraulic drop in fishway (ft)
  0.8 0.8 1.0
Table 6.2 Stream Classification by Montgomery and Buffington (from Bunte and Abt 2001)
Stream gradient, range and mode
(m/m)
Stream Typical bed material Dominant Sediment Dominant sediment storage Typical pool spacing*
0.03 - 0.20
(0.08 - 0.20)
Cascades Cobble-boulder Fluvial, hillslopes, debris flows Around flow obstructions < 1
0.02 - 0.09
(0.04 - 0.08)
Step-pool Cobble-boulder Fluvial, hillslopes, debris flows Bedforms 1 - 4
<0.02 - 0.05
(0.02 - 0.04)
Plane-bed, forced pools Gravel-cobble Fluvial, bank failure, debris flows Overbank None
<0.001 - 0.03
(0.01)
Pool-riffle Gravel Fluvial, bank failure Overbank, bedforms 5 - 7
< 0.001 Dune-ripple Sand Fluvial, bank failure Overbank, bedforms 5 - 7

Values in parentheses are the modes of the observed stream gradient distribution; * in terms of channel widths

Table 6.3 Morphological Characteristics of the Major Rosgen Stream Types (Bunte and Abt 2001)
Stream Type Morphological characteristics
A Step-pool, or cascading: plunge and scour pools, high energy, low sediment storage, stable;
B Riffles and rapids: some scour pools, bars rare, stable;
C Pool-riffle sequences: meandering, point bars, well developed floodplain, banks stable or unstable;
D Braided: multiple-channels, shifting bars, scour, deposition, high sediment supply, eroding banks;
DA Anastomosing: multiple channels, pool-riffle, vegetated floodplain, adjent, wetlands, stable banks;
E Meadow meanders: well-developed floodplain, riffle-pool, relative high sediment conveyance;
F Valley meanders: incised into valleys, poor floodplain, pool-riffle, banks stable or unstable;
G Gullies: incised into hillslopes and meadows, high sediment supply, unstable banks, step-pool.
Table 6.4 Angle of Repose, Shield's Parameter and Critical Shear Stress Values for Gravel-, Cobble- and Boulder-Sized Particles (Bates et al. 2006)
Particle size classification Particle size, Di
(mm)
Angle of repose (Φ), f
(degrees)
Shield's parameter a, τ* Critical shear stress, τc
(lb/ft2)
very large boulders > 2048 42 0.054 37.37
large boulders 1024-2048 42 0.054 18.68
medium boulders 512-1024 42 0.054 9.34
small boulders 256-512 42 0.054 4.67
large cobbles 128-256 42 0.054 2.34
small cobbles 64-128 41 0.052 1.13
very coarse gravels 32-64 40 0.05 0.54
coarse gravels 16-32 38 0.047 0.25
medium gravels 8-16 36 0.044 0.12
fine gravels 4-8 35 0.042 0.057
very fine gravels 2-4 33 0.039 0.026
Table 7.1 Design Recommendations Based on Channel Types (adapted from Bates et al. 2006)
REFERENCE CHANNEL TYPE TYPICAL CONDITIONS RECOMMENDED DESIGN STRATEGIES
Bed Material Dominant roughness & structural elements Slope Entrenchment Streambed mobility
Dune-ripple Sand to medium gravel Sinuosity, bedforms, banks. Small debris may provide structure <0.1 Slight Termed "live bed"; significant sediment transport at most flows
  • Simulated bed can be native bed material or imported dense mix based just on D100 of reference reach.
  • Bands or clusters of material added to simulate diversity from wood.
  • Banklines designed to be immobile
Pool-riffle Gravel, often armored Bars, pools, grains, sinuosity, banks 0.1-2 Slight Armored beds usually mobilize near bankfull
  • Simulated bed D100, D84, D50 and Dmax same as reference reach.
  • Material smaller than D50 is dense mix based on D50.
  • Bands or clusters of material added for diversity.
  • Key features, banklines designed to be immobile.
Plane-bed Gravel to cobble, usually armored Grains, banks 1-3 Slight to entrenched Near bankfull
  • Simulated bed D100, D84, D50 and Dmax same as reference reach.
  • Smaller material size distribution is dense mix based on D50.
  • Key features, banklines designed to be immobile.
Step-pool Cobble to boulder Steps, pools, banks. Debris may add significant structure 3-10 Moderately entrenched to entrenched Fine material moves over larger grains at frequent flows depending on size; often >Q30
  • Steps are spaced same as reference reach
  • Step-forming rocks are sized to be immobile.
  • Smaller material size distribution is dense mix based on D50 of material other than steps in reference reach
  • Banklines designed to be immobile.
Cascade Boulder Grains, banks 8-30 entrenched Small bed material moves at moderate frequencies (floods higher than bankfull). Larger rocks are immobile in flows smaller than ~Q50
  • Simulated bed D100, D84, D50 and Dmax same as reference reach.
  • Smaller material size distribution is dense mix based on D50.
  • Key features, banklines designed to be immobile.
Bedrock Rock with sediment of various sizes in transport over rock surface Bed and Banks any any Bedload moves over bedrock at various flows depending on its size. May be thin layer of alluvium over bedrock. Wood can strongly affect sediment mobility.
  • Stream simulation bed is bedrock.
  • Banklines and roughness elements are important and must be designed for stability, which requires embedding, clustering or anchoring boulders.
  • Condition, extent, and shape of bedrock are important.
  • Bottomless structure reduces rock removal compared to full pipe and can be anchored and shaped to rock.
Channels in cohesive material Silt to Clay Sinuosity, banks, bed irregularities any any Fine sediment moves over immobile bed at moderate flows depending on its size. May be thin layer of alluvium over immobile bed.
  • Stable cohesive bed and banks cannot be constructed in culvert.
  • Culvert walls may simulate smooth natural clay banks.
  • Bottomless structure might leave clay bed undisturbed.
Table 7.6 Baffle Hydraulics (Bates et al. 2003)
(Limits shown are the limits of experimental data or valid correlation for the coefficients and exponents; the designations in the first column refer to the specific experiment; the fourth row is extrapolated from WB-1; the seventh row is extrapolated from WB-4)
  Zo L C a Limits
WB-2 0.15D 0.6D 5.4 2.43 0.25 y0/D < 0.8
WB-1 0.15D 1.2D 6.6 2.62 0.35 y0/D < 0.8
  0.15D 2.4D 8.5 3.0  
WB-3 0.10D 0.6D 8.6 2.53 0.35 y0/D < 0.8
WB-4 0.10D 1.2D 9.0 2.36 0.20 y0/D < 0.8
  0.10D 2.4D 9.6 2.5  
Table 7.7 Water Velocity Requirement for Culvert Installations in Oregon, Customary Units (Robison et al. 1999)
Culvert Length (ft) Salmon & Steelhead Adult Trout (>6") Juvenile Salmonids
Under 60' 6.0 4.0 2.0
60-100' 5.0 4.0 2.0
100-200' 4.0 3.0 see Note below
200-300' 3.0 2.0 see Note below
Over 300' 2.0 1.0 see Note below
Updated: 02/11/2015
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000