WALLA WALLA BASIN FLOW AUGMENTATION RECOMMENDATIONS
FEBRUARY 2004
PREPARED BY
FISHERIES PROGRAM
DEPARTMENT OF NATURAL RESOURCES
THE CONFEDERATED TRIBES OF THE UMATILLA INDIAN RESERVATION
P.O. BOX 638,
PENDLETON, OR
INTRODUCTION
The Confederated Tribes of the Umatilla Indian Reservation (CTUIR) is working with the Army
Corps of Engineers as sponsors of a feasibility study to examine flow enhancement options for
fish in the Walla Walla River Basin. This work was developed from a reconnaissance study
(USACE 1997) and has progressed to a basin-wide feasibility study. The flow augmentation
recommendations listed below are not “minimum instream flow recommendations” which have
been defined locally as those flows above which new water rights may be granted without impact
to fisheries or aquatic values. Minimum instream flow recommendations are higher than what
normally occurs during summer flows and will not be consistent with flow augmentation
recommendations described in this document.
There is not a single flow quantity that suddenly transforms unsuitable habitat into optimum
salmonid habitat once the final cfs is added. Recommending a single discharge for specific
reaches is somewhat counter intuitive for fluvial and biological systems that are constantly in
flux. However, flow targets for planning and evaluation are needed and it did not seem
reasonable to recommend augmentation flows that would frequently exceed natural flow
conditions. Furthermore, incremental improvements in salmonid habitat generally diminish as
flows increase.
The costs and benefits of various summer rearing flow augmentation strategies will likely drive
the quantity of augmented flows. The first priority is to secure flows for adult and juvenile
passage so that habitat in the headwaters can be utilized. The second priority is to secure
additional flows for summer rearing. For example, on the mainstem Walla Walla River
obtaining 80 cfs for the entire summer may be much more cost effective than acquiring 100 cfs.
The preferred alternative under that scenario would be 80 cfs. On the other hand, conditions may
allow a design that could provide 110 cfs for only a little more than it would cost to supply 90
cfs. In that situation, augmenting 110 cfs would likely be the preferred action
Water temperature is an important factor in flow management when salmonid rearing is
involved. Not only will additional flow provide more habitat at monitoring points, it will also
provide more miles of suitable habitat downstream. In the summer, water temperatures generally
increase as the water moves downstream. The justification for securing additional flow is based
in part on thermodynamics. For a hypothetical example, 100 cfs of cold water may only increase
weighted usable area at a given IFIM transect by 10-20% over 60 cfs. However, many additional
miles of summer salmonid rearing habitat would be gained with higher flows because the cold
water would persist much farther downstream. We recommend that both weighted usable area
and total miles of suitable habitat be included in the cost/benefit analysis of various flow
augmentation strategies.
Flow augmentation planning for summer rearing habitat should strive to keep cold clean water in
natural channels. Cold water from springs and cold tributaries should be managed so that it
reaches the river. If possible, water sources with thermal, sedimentary and agricultural pollutants
should be routed into irrigation canals and not through salmonid habitat in natural streams. In
addition to the restoration of flows, aggressive restoration of riparian vegetation and other efforts
could further expand the number of river miles of suitable salmonid rearing area by improving
habitat and temperature profiles in the lower river. Securing adequate flows is an essential part
of basin restoration and should occur in unison with other restoration actions.
RECOMMENDED AUGMENTATION FLOWS
Walla Walla River below Milton Freewater
The flow concepts we propose for the mainstem of the Walla Walla River below MiltonFreewater have several components including: 1) spring flows for migrating adults and smolts;
2) summer rearing flows with an initial range of 50 cfs, and 3) improved summer rearing flows
with a range near 100 cfs (Table 1, Figure 1 and 2). These ranges may not be optimal for fish
but represent a workable compromise. Optimum flows for fish are unrealistic and include
management of all of the available water for fish all of the time.
Table 1. Flow augmentation recommendations for the Walla Walla River below MiltonFreewater.
Flow
(CFS)
150
50
100
Purpose
Timing
Salmon and Steelhead Migration
Juvenile Rearing Habitat
Expand Rearing Habitat
Spring through June
July through October
July through October
TOTAL
Acre Feet
Needed
15,000
12,000
27,000
Estimates of the acre feet needed for fish flows assumes: 1) the 2002 minimum flow of 25 cfs
would contribute; 2) additional flows developed through the HCP process were not
considered, and 3) the table does not include water needs for the minimum pool of a storage
site, wildlife needs, and other beneficial uses.
Adult and Juvenile Migration
Migrating adult spring Chinook salmon need sufficient flows from April through June. Flows in
Table 2 show that historical flows ranged from 254 to 665 cfs at Milton Freewater during the
spring. Steelhead need migration flows from January through May at the minimum. While
flows between 250 to 650 cfs would be beneficial for both outmigrants and returning adults,
CTUIR experience on the Umatilla River with spring Chinook and examination of the river
2
channel, suggests that 150-200 cfs would likely be an adequate migration flow target. However,
addition flows would be considered beneficial and desirable. CTUIR provides this target flow
based on comparisons of flows needed in the Umatilla Basin, observations of strays in 1998 and
historical records (Table 2). CTUIR has monitored adult returns and flows in the Umatilla Basin
since 1989 and 150-200 cfs appears to be adequate for migrating adults and smolts. In 2001, 47
adult spring Chinook salmon from hatchery programs in adjacent basins returned to the Walla
Walla River and were observed at Nursery Bridge Dam (Figure 3). Adult returns appeared to
end abruptly in association with reduced flows. This data matches the conceptual charts
presented in Figures 1 and 2. These figures suggest that flows should be augmented through
June for adult spring Chinook to migrate safely to the headwaters. Otherwise portions of the run
may not be able to return to the headwaters to spawn. IFIM flow studies conducted by Hal
Beecher and reported in Mendel (et al. 2001) indicate that steelhead spawning habitat weighted
usable area was optimum at 182 CFS. Weighted usable area of spawning habitat is not likely an
important factor limiting summer steelhead abundance below Milton-Freewater (given suitability
of summer habitat and spawning habitat currently available at existing flows). However,
summer steelhead are observed spawning in the mainstem below the state-line (Glenn Mendel,
WDFW, Dayton, personal communication; Brian Mahoney, CTUIR, Milton-Freewater, personal
communication). Higher spring flows matching the natural hydrograph would benefit steelhead
spawning below Milton-Freewater as well as migrating adults and juveniles.
Figure 1. Conceptualized schematic of current flow overlaid with flow needs of adult spring
Chinook (red or medium grey area) and summer steelhead (green or dark grey area), year-around
rearing of juvenile salmonids, and out-migration flows for smolts (yellow or light grey area).
3
Figure 2. Conceptualized schematic of current and historic flows overlaid with proposed
augmentation flow ranges (grey or yellow area) designed to provide for passage of adult spring
Chinook and summer steelhead, year-around rearing of juvenile salmonids, and out-migration
flows for smolts.
6/9/01
6/7/01
6/5/01
0
6/3/01
0
6/1/01
20
5/30/01
1
5/28/01
40
5/26/01
2
5/24/01
60
5/22/01
3
5/20/01
80
5/18/01
4
5/16/01
100
5/14/01
5
5/12/01
120
5/10/01
6
5/8/01
140
5/6/01
7
Estimated River Flow (CFS)
Flow
160
5/4/01
Number of Spring Chinook Salmon
Chinook
8
Figure 3. Adult spring Chinook salmon returns to Nursery Bridge Dam in 2001 and associated
Walla Walla River flow estimates.
Flows for Salmonid Rearing Below Milton-Freewater
During most of the 1900s, the Walla Walla River below Milton-Freewater became unsuitable for
juvenile salmonids each summer when irrigators diverted water for agricultural needs (Volkman
4
2001). Recently, ESA related flow requirements (25 cfs) have provided enough flow for
salmonids to migrate through the reach. Currently some juvenile salmonids rear in the reach all
summer (Contor and Sexton 2003). The 25 cfs represents an important beginning. However,
considerably more cold water in the summer would greatly enhance and extend suitable
salmonid rearing habitat downstream from Milton-Freewater.
The Washington Department of Fish and Wildlife, the Oregon Department of Environmental
Quality (ODEQ) and the Confederated Tribes of the Umatilla Indian Reservation each developed
flow augmentation recommendations of about 100 cfs using separate methods for the Walla
Walla River below Milton-Freewater, Oregon.
Oregon Department of Environmental Quality Draft Process
Oregon Department of Environmental Quality estimated what August flows would be without
human factors (primarily irrigation). They used hydrologic modeling techniques and accounted
for flow losses for the reach below Milton-Freewater. They estimated the natural discharge in
August below Milton-Freewater would average 118 cfs with a range from 109 to 139 (Don
Butcher, Oregon DEQ, Pendleton Office, 2002 unpublished report and personal communication).
In another exercise they estimated flows would be near 100 cfs (DEQ, Pendleton Office, draft in
preparation, 2004).
Washington Department of Fish and Wildlife’s Suitable Flow Estimate
Washington Department of Fish and Wildlife reported that “juvenile steelhead habitat increased
most rapidly up to 100 cfs in the Walla River” below Mill Creek (Mendel, et al. 2001). Their
estimate was based on the incremental use of an IFIM model called the Physical Habitat
Simulation Model (PHABSIM) using three calibration flows at nine transects. Their model is
considered suitable for flows from 10 to 300 cfs. The 100 cfs value is similar to historical
summer flows and what CTUIR recommends.
CTUIR Flow Recommendations for Salmonid Summer Rearing Habitat
CTUIR based their flow recommendations on historical data when spring Chinook were
abundant (Volkman, 2001). This is a very basic use of empirical data. Adequate flows had to
exist historically for Chinook to be abundant, and we assume that similar flows would be
sufficient for recovery today. This does not mean that recovery will occur if other limiting
factors are ignored.
CTUIR looked at flow records from 1903-1905 obtained from the U.S. Geological Survey and
the Oregon Water Resources Department (Table 2). The flow of 100 cfs represents the low
summer flow at Milton-Freewater before significant irrigation diversions. The average flows
during the summer and late fall ranged from 120 cfs to 140 cfs. Combining flows from the
North and South Forks, using USGS data through 1991, also indicates that at least 100 cfs
flowed in the mainstem during the summer down to the diversions at Milton-Freewater. CTUIR
crews have sampled juvenile spring Chinook, summer steelhead and bull trout in the MiltonFreewater reach, above the diversions, during August 1999, when flows were near the
recommended 100 cfs (Contor and Sexton 2003). Securing augmentation flows for irrigation
needs and keeping 100 cfs of cold water in the main channel would improve existing habitat and
extend salmonid rearing for many miles below Milton-Freewater. To estimate acre feet of water
needed to augment flows below Milton-Freewater (Table 1), we assumed the existing 25 cfs
5
would continue to contribute. We did not include HCP flows in the table or storage needs for
minimum pools, wildlife needs or other beneficial uses of water that may be reasonable and
prudent.
From a hydraulic and fish habitat perspective, it would be hard to conceive of a reasonable flow
recommendation that did not match the basin and stream channel. Channels normally form in
proportion to basin attributes (peak discharge, valley slope, geology, area, climate, topography
etc). PHABSIM utilizes channel attributes in concert with flow, depth and velocity combined
with known habitat suitability data for salmonids (depth, velocity etc). It is not surprising that
the PHABSIM method showed that benefits increased most rapidly until discharge was similar to
historical summer flows. One would also expect similar values when using ODEQ’s methods to
estimate what contemporary summer flows would be without diversions. These rudimentary
relationships between watershed and base flow (exceptions granted) is why CTUIR considers
100 cfs a reasonable summer flow target (July through October) for the Walla Walla River below
Milton-Freewater, Oregon.
6
Table 2. Summary of mean daily discharge estimates from gages in the Walla Walla River Basin (Oregon Water Resources
Department, www.wrd.state.or.us).
North Fork Walla Walla River, gage number 14010800, discharge in cubic feet per second, period of record: 10/1969 ~ 10/1991
Month
(CFS)
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec Period of Record
Maximum
644.0 872.0
670.0 339.0
473.0
394.0
40.0
41.0
23.0
108.0 243.0 475.5 Max
872.0
Discharge
Mean Discharge
70.0
77.6
95.2 115.2
94.4
41.6
11.8
8.0
7.4
9.5
25.9
48.1 Mean
50.2
Minimum Discharge
5.8
11.0
24.0
32.0
13.0
6.5
4.0
3.4
3.5
4.3
4.4
5.9 Min
3.4
South Fork Walla Walla River, gage number 14010000, discharge in cubic feet per second, period of record: 02/1903 - 10/1991
Month
(CFS)
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec Period of Record
Maximum
1800
1190
890
930
996
914
299
210
425
310
708
1870 Max
1870
Discharge
Mean Discharge
174.0
188.0
214.2
279.5
302.7
203.3
123.2
108.6
106.9
110.2
134.5 165.2 Mean
175.8
Minimum Discharge
80
74
98
129
110
88
81
77
75
74
76
80 Min
74
Walla Walla River near Milton-Freewater, gage number 14012000, discharge in cubic feet per second, period of record: 02/1903 - 09/1905.
Month
(CFS)
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec Period of Record
Maximum
460.0
436.0 2220.0 2220.0
830.0
472.0
225.0
198.0
369.0
488.0
820.0
560.0 Max
2220.0
Discharge
Mean Discharge
214.4
222.7
434.8
665.1
497.0
253.9
148.0
121.7
134.3
159.2
233.2
232.7 Mean
285.6
Minimum Discharge 150.0
128.0
200.0
310.0
275.0
145.0
100.0
97.0
100.0
125.0
143.0
140.0 Min
97.0
Walla Walla River near Touchet, gage number 14018500, discharge in cubic feet per second, period of record: 10/1951 - 09/1987
Month
(CFS)
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec Period of Record
Maximum
14500
9310
7390
5610
2770
3210
457
268
850
1630
2770 20300 Max
20300
Discharge
Mean Discharge
1168.6 1340.6 1205.2 1118.5
699.1 253.2
42.6
19.4
44.6
92.9
291.8 849.3 Mean
590.0
Minimum Discharge
200
162
117
65
37
4.9
0.0
0.0
2.6
3.8
33
84 Min
0.0
7
Mill Creek, Touchet River and Touchet River Tributaries
For Mill Creek and the Touchet River and selected tributaries, we concur with flow
recommendations developed by Barber (et al. 2001, 2003a, 2003b), Caldwell (et al.
2002), and Barber and Saul (2001; Table 3). Our recommendations include:
1) spring flows for the migration of adult and juvenile salmonids;
2) spring flows for steelhead spawning;
3) summer flows for salmonid rearing;
4) an understanding that fall and winter flows will met or exceed September flow
recommendations, and
5) an understanding that high flows will continue to provide bank-full flow events at
least once every two or three years to maintain channel form and function.
Table 3. The Confederated Tribes flow augmentation recommendations for Mill Creek
and Touchet River and Tributaries as adapted from Barber’s IFIM studies (Barber et al.
2003a, 2003b). Augmentation flow targets for October-February would be at or above
September flows.
Spring
Summer
Stream and Reach
Mar Apr May June July Aug Sept
Mill Creek above Blue Creek
100 100 100 100* 40
40
40
Mill Creek below Blue Creek**
100 100 100 100* 40
40
40
Coppei Creek, forks to the mouth
50
50
25
10
10
10
10
NF Coppei Creek
15
15
10
5
5
5
5
Touchet, forks to the mouth**
200 200 200 150
60
50
50
NF Touchet above Wolf Fork
90
75
60
30
30
30
40
* recommended augmentation flows above Barbers’ recommendations are for spring Chinook
adult returns
** includes reaches outside of Barber’s (et al. 2003a, 2003b) study areas
8
Literature Cited
Barber, Michael, Steve Juul, Darin Saul, Tom Cichosz, and Craig Rabe. 2001. Instream flow
incremental methodology analysis and streamflow data collection of the Touchet River
System within Columbia Country. Columbia Conservation District, Dayton Washington. 99
pp.
Barber, Michael and Darin Saul. 2001. Analysis of instream flow incremental methodology
investigation of the upper Touchet River System. Washington State University, Pullman,
Washington. 12 pp.
Barber, Michael, Ben Floyd, and William Pope. 2003a. Instream flow incremental methodology
analysis of the North Fork Touchet River above the Wolf Fork tributary within Columbia
County. Columbia Conservation District, Dayton Washington. 49 pp.
Barber, Michael, Teresa Hauser, Patrick Flanagan and Janet Snedecor. 2003b. Minimum
instream flow studies of Mill Creek above Blue Creek, Coppei Creek and North Fork Coppei
Creek. State of Washington Water Research Center, Washington State University, Pullman,
Washington. 57 pp.
Caldwell, Brad and Jim Shedd, and Hall Beacher. 2002. Walla Walla River fish habitat analysis
using the instream flow incremental methodology. Washington State Department of Ecology
and Department of Fish and Wildlife. Technical Report 02-11-009. 38 pp.
Contor, Craig and Amy Sexton. 2003. The Walla Walla Basin natural production monitoring
and evaluation project. Progress Report 1999-2002. Confederated Tribes of the Umatilla
Indian Reservation. Report submitted to Bonneville Power Administration, Project No.
2000-039-00. 281 pp.
Mendel, Glen, David Karl, and Terrence Coyle. 2001. Assessments of salmonids and their
habitat conditions in the Walla Walla River Basin of Washington. 2000 Annual Report.
Report to BPA. Project 199802000.
Oregon Department of Environmental Quality. 2004. Draft in Preparation. Stream temperature
goals for the Walla Walla River Bain in Oregon: total maximum daily load and water quality
management plan. Oregon Department of Environmental Quality, Pendleton Oregon.
Oregon Department of Environmental Quality. 2002. Walla Walla Basin Flow Potential
Estimation. Unpublished report. Oregon Department of Environmental Quality, Pendleton
Oregon. 6 pp.
US Army Corps of Engineers. (1997). Walla Walla River Watershed, Oregon and Washington,
Reconnaissance Report, Walla Walla, Washington.
Volkman, Jed. 2001. Walla Walla Habitat Restoration Project. 2000 Annual Report.
Department of Natural Resources, Confederated Tribes of the Umatilla Indian Reservation.
Report to Bonneville Power Administration, Portland Oregon
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