Grand Canyon Monitoring and Research Cent

WY 2004 Experimental Fine-Sedimen

Paria River Inputs & 41,000 vs. 45,0

Sand Bar Simulations
Southwest Biological Science Center

Paria River Sand Inputs

July 1 – Sept. 24, 2004

Paria River

– has produced 284,000 + 20% metric tons of sand since 

July 1st, with the majority of this coming from 2 September floods

Lesser Tributaries

– Marble Canyon tributaries have produced 

about 50,000 to 100,000 metric tons of sand since July 1st

First Sand Trigger

– currently, 56 to 88% of the way to the first 

trigger for dam re-operation (8,000 cfs constant vs. 6,500-9,000 cfsfluctuations) for a flow test to identify the most conservative sand transport release pattern for retaining tributary inputsBHBF Sand Trigger

– currently, 25 to 43% of the way toward the 

800,000 metric ton flood trigger for the BHBF test

Dr. Davi

Mudd
Southwest Biological Science Center

41,000 vs. 45,000 cfs

BHBF Simulations of 

Sand Bar Responses

BHBF of 60-hour Duration

– the QUESTION: “How different will the 

sand bar responses be in Marble Canyon with a high-flow test that is 4,000 cfs lower in discharge and stage than would occur if magnitude matched the 1996 experiment?”Sand Supply Assumed to be Greater than 2000 LSFF or 1996 BHBF

–

“For the sediment input, I've looked over Topping's rating curves at Phantom and chosen 

values for the first day of the '96 release, which corresponds closely with the 1956 fine bed 

rating curve David has for 25% bed coverage. For grain size, I'm using 0.12 mm, which is the value for the '56 condition. I'll use the longitudinal variation Scott determined from your Lagrangian sampling to estimate the local sand discharges from the Phantom rating curves, as before. This approach probably yields a conservative estimate of the sand supply if the high flow is triggered, especially closer to the mouth of the Paria, but is higher than either the '96 or LSSF supplies.

”

Preliminary Results - Dr. Stephen M. Wiele (USGS – WRD)
Steve Wiele’s Preliminary Sand-Bar Simulations sugge

At River Mile miles below tRiver confluethe 41,000 & cfs simulationthat the CatheWash Eddy wdramatically from the exiscomplex (this ultimate “canstudy site)
Steve Wiele’s Preliminary Sand-Bar Simulations sugge

However, at RMile 22, (21 below the Parconfluence) tcfs simulation that the 22-Mwill add subssand to the excomplex, but slightly lessethan would ounder a 45,00BHBF
Steve Wiele’s Preliminary Sand-Bar Simulations sugge

And at River (29 miles belParia River confluence) tcfs simulation that the 30-Mwill add sand existing bar cand the respobe nearly identhat which wooccur under a cfs BHBF (Nbefore deposi
Steve Wiele’s Preliminary Sand-Bar Simulations sugge

While at Rive43, (42 miles the Paria Rivconfluence) b41,000 & 45,simulations sthat the EminEddy will losamount of santhe existing bcomplex – No building undeflow!
Steve Wiele’s Preliminary Sand-Bar Simulations sugge

At River Milmiles below River conflumiles below confluence) cfs simulatiothat the Paliswill dramaticsand to the ecomplex, buslightly lessethan would ounder a 45,0BHBF!
Preliminary Conclusions on the BHBF Simulations

The “net” diffebetween the 445,000 cfs BHpredicted to be respect to indibar responses, variability in bresponse longibelow the dam potentially largA positive bar Upper Marble without complexhausting the in 60 hours woencouraging