9700

• UCREFRP Catalog Number: 9700
• Author: Hayes, J.W., K.E. LaGory and G.L. Burton.
• Title: Consideration of site-specific floodplain inundation thresholds in implementing peak flow magnitude and duration recommendations in the middle Green River, Utah.
• USFW Year: 2005.
• USFW - Doc Type: Argonne National Labortory, Argonne, Illinois.
• Copyright Material: NO

Green River Floodplain Inundation

19

June 2005

600

500

- - Muth et al. (2000)
- - 368 ems (13K cfs)
-396 ems (14K cfs)
-424 ems (15K cfs)

20 days

/

27 Days

- 400
.!!
M
E
-

Q)
~ 300
C'lS
.c
CJ
.!!
c 200

100

o
19-Apr

4-May

19-May

3-Jun

18-Jun

3-Jul

Date

Figure 6. Hypothetical Example of Flows at the Jensen Gage Under the Muth et al.
(2000) Flow Recommendations (527 m3/s [18,600 cfs] Connection Flow Target) and
Alternative Flow Management Strategies with Extended Duration Connection Flow
Levels of368 m3/s (13,000 cfs), 396 m3/s (14,000 cfs), and 424 m3/s (15,000 cfs).

return frequency of flows that permit inundation of such areas (about 10% to 30% exceedance
under regulated flows) may preclude timely return to the main channel of razorback suckers that
mature in such areas and would increase the likelihood that the depression floodplains would dry
out before those individuals could return.

The proposed flow management strategy would provide the following benefits:

· Most priority depression floodplains (55% to 63%) would be connected to the main
channel, fully inundated, and available as nursery habitats for razorback suckers in
60% to 70% of years.

· Connection of priority depression floodplains to the main channel would be frequent
enough to allow juvenile and subadult razorback suckers to return to the main channel
in most years;

· The duration of floodplain connection that could be provided for a given volume of
water would be longer than under the existing recommendations and would increase
the probability that larvae are entrained in a given year;