Hydraulics & Waterways

Oral

396266 - Comparison of Two Rating Approaches for Flow Monitoring at Uncontrolled Culverts under Small Head Differences

Wednesday, June 6
8:30 AM - 10:00 AM
Location: Regency Room
Co-Authors: Sayed Hajimirzaie, West Palm Beach, FL – South Florida Water Management; Joe Buzard, West Palm Beach, FL – South Florida Water Mangement District

Culverts are key water control structures in storm-water treatment wetlands managed by the South Florida Water Management District (SFWMD). However, the operation and maintenance of stilling wells with encoder-float stage sensors, standard in SFWMD to monitor water levels at uncontrolled culverts, concurrently with index-velocity (IV) instrumentation, is expensive. As part of a cost-reduction initiative, we compared the reliability and accuracy of a distributed-type hydraulic rating (Bodhaine, 1968) with an IV rating for flow monitoring at uncontrolled culverts under low-head differences (Δh<0.05’). Concurrent measurements of head and tailwater by standard stilling wells, index-velocities by a Doppler IV-meter, discharges by an Acoustic Doppler Flow Meter and head-drop by a high-resolution pressure-differential sensor were used to calibrate the ratings. For head-drops Δh<0.05’ measured by standard wells, the hydraulic rating was found unreliable. For the 6-ft-diameter, 60-ft-long culverts of interest, values of Δh<0.05’ correspond to Qs<35cfs, which may contribute up to 67% of the total annual volume they convey. Stages measured using sensors of higher resolution and sampling frequency than sensors in standard wells yielded unbiased head-drop estimates for Δh>0.01’, corresponding to full-pipe Qs>16cfs. Our study shows that IV-ratings are not only sufficiently accurate and reliable to monitor Qs>5cfs (mean full-pipe velocity of ~0.2ft/s), but also more economical than standard hydraulic ratings, which could be used to rate Qs≥5cfs only if Δh≥0.01’can be measured accurately.

Juan A. Gonzalez-Castro, Ph.D., P.E.

Stramgauging Unit Lead
South Florida Water Mgmt Dist

Presentation(s):

Send Email for Juan Gonzalez-Castro

Seyed Hajimirzaie, PhD, PE, PH

STAFF ENGINEER
South Florida Water Management District (SFWMD)

Seyed (“Haji”) Hajimirzaie, Ph.D., P.E., P.H
South Florida Water Management District (SFWMD)
Applied Hydraulics Section

I have received my Ph.D. in Civil and Environmental Engineering from the University of Iowa, IIHR—Hydroscience & Engineering (IIHR). My Ph.D. dissertation was an interdisciplinary study with components of environmental hydraulics as well as sediment transport. Currently, I am a full time employee at Hydrology and Hydraulics (H&H) Bureau at South Florida Water Management District (SFWMD).
Special Fields of Knowledge:
• Experimental Fluid Dynamics, Environmental Hydraulics, River Restoration and Sustainability, Image-Based Flow Velocimetry, Unsteady Flows, Vortex-Dominated Flows, River Hydraulics, Hydraulic Structures, Sediment Transport

Presentation(s):

Send Email for Seyed Hajimirzaie


Assets

396266 - Comparison of Two Rating Approaches for Flow Monitoring at Uncontrolled Culverts under Small Head Differences



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for Comparison of Two Rating Approaches for Flow Monitoring at Uncontrolled Culverts under Small Head Differences