NYC Resources311Office of the Mayor

Hydrology

Opportunistic Point Velocity Measurements

2003

Velocity measurements were collected by NRG to assess the potential suitability of spawning and rearing habitat for anadromous fish and to identify potential passage obstacles with respect to stream velocities.

Opportunistic point velocity measurements were taken between Drew Gardens and River Park, and especially at points throughout Bronx River Park. Sites are in potential rearing and spawning reaches as well as places suspected to be possible velocity barriers to fish passage.

Methods

Velocity readings were taken with a Marsh-McBirney Flow meter using 10 second averages.

Floating object measurements were taken 40-50 ft. from the bank, usually on the slower-flowing sides of the channel.

Results

Point Velocity Measurements on the Bronx River

3/26/03

Location Velocity (ft/s) at 60% depth
River Park (at xs 3) 1.69
DG to River Park (at xs 2) 1.96
Drew Gardens (at xs 1) 1.57

6/5/03

Location Depth (cm) Dist from bank (ft) Velocity (ft/s)
20% depth 80% depth Avg.
At Bend - Point Bar Culvert at LB, DS of Burke Ave Bridge 110 ~10 1.15 0.9 1.03
90.00 ~10 1.20 1.00 1.10
102.00 ~15 1.90 1.30 1.60
Total Avg: 1.35
US of Kazimiroff Bridge on Left Channel 81.00 ~3 1.17 0.96 1.07
76.00 ~7 1.52 1.18 1.35
Total Avg: 1.21
Shoelace Boulder Vane 211th Street 88.00 ~4 1.09 1.06 1.08
105.00 ~18 2.20 1.60 1.90
107.00 ~22 2.00 1.50 1.75
Total Avg: 1.58
DS of Muskrat Cove Btw Nereid Bridge and Muskrat Cove 100.00 ~7 2.45 2.00 2.23
74.00 ~8 1.30 1.10 1.20
76.00 ~20 2.30 1.90 2.10
74.00 ~25 2.70 2.30 2.50
Total Avg: 1.93

6/13/03

Location Depth (cm) Dist from bank (ft) Velocity (ft/s)
20% depth 80% depth Avg.
Wild Asia 62 ~10 0.64 0 0.32
90 ~11 0.5 0.25
DS of Fordham Brdge 85.00 ~10 0.35 0.05 0.20

Floating Object Velocities (ft/s)

Location Object Time (s) Distance (ft) Velocity (ft/s)
Wild Asia twigs/leaves 9.63 20.67 2.15
twigs/leaves 12.89 20.67 1.60
twigs/leaves 11.47 20.67 1.80
twigs/leaves 15.8 20.67 1.31
Avg: 1.72
DS of Fordham Bridge orange peels 16.72 26.5 1.58
orange peels 19.86 26.5 1.33
orange peels 19.67 26.5 1.35
orange peels 15.84 26.5 1.67
orange peels 21.67 26.5 1.22
Avg: 1.43

Download Opportunistic Point Velocity Measurement data
(Excel, 25KB)

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