Carlton Complex Fire, State and Private Lands, Burned Area
Emergency Response Aquatic Resources Report
Prepared by:
Jarred Johnson
Fisheries Habitat Biologist — Yakama Nation
509-881-1462
and
Jennifer Molesworth
Methow Sub-basin Liaison — Bureau of Reclamation
509-881-8699
1
Table of Contents
I.
II.
III.
IV.
V.
VI.
VII.
VIII.
IX.
X.
XI.
XII.
Executive Summary
Objectives
Assessment Methodology
Critical Fisheries Values at Risk
Fish Species & General Life Histories
a. UCR Spring Chinook
b. UCR Summer Steelhead
c. CR Bull Trout
d. Pacific Lamprey
e. Other Affected Fish Species
Fire Affected Watersheds and Sub-watersheds
a. Lower Methow River
b. Bear Creek
c. Beaver Creek
d. Frazer Creek
e. Benson Creek
f. Black Canyon Creek
g. Squaw Creek
h. Gold Creek
i. Libby Creek
j. Okanogan River
k. Loup Loup Creek
Post Fire Affects
a. Riparian Shade and Stream Temperature
b. Stream Nutrients
c. Surface Runoff and Erosion
i. Road and Fireline Contribution
d. Mass Wasting and Debris Flows
e. Large Woody Debris
Hydrologic Changes
a. Model Exports
Treatment Recommendations
Recommendations for Near and Long-term Recovery
Monitoring Recommendations
References
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List of Figures and Tables
(In order of appearance in the document)
Figure 1. ESA Listed Fish Distribution and Burn Severity
pg. 6
Figure 2. Steelhead Redd Distribution
pg. 8
Figure 3. Life History Diagram
pg. 9
Table 1.
Watershed & Sub-watershed Fire Impacts
pg. 15
Table 2.
Riparian Vegetation Impacts
pg. 16
Figure 4. Photo of Beaver Creek Riparian
pg. 16
Figure 5. Road Bed Surface Erosion at Failed Culvert
pg. 17
Figure 6. Ash Flows in Beaver Creek
pg. 17
Table 3.
pg. 18
Dozer Line and Road Densities
Figure 7. Convective Storm Induced Debris Flow
pg. 19
Table 4. Wildcat and AGWA Hydrolic Modeling Outputs
pg. 20
Figure 8. AGWA Map Output
pg. 22
Figure 9. Photo of Cottonwood Regeneration
pg. 23
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I.
EXECUTIVE SUMMARY
The Carlton Complex Fire affected three ESA-listed fish stocks in the Methow and Okanogan
subbasins as well as several non-listed game fish, non-game fish and forage fish species. This
report focuses on the acute fire effects and post-fire long-term effects predicted for the ESAlisted stocks and important recreational game fishes.
The Methow River supports runs of Upper Columbia River (UCR) spring Chinook salmon
(endangered), Upper Columbia River summer Steelhead (threatened) and Columbia River Bull
Trout (threatened) and their designated “Critical Habitat.” Other species of interest include
Coho salmon, summer Chinook, cutthroat, red band/rainbow, and Pacific lamprey. The
Okanogan River supports populations of UCR steelhead (threatened) and their critical habitat as
well as sockeye salmon, and summer Chinook salmon.
The extent to which wildfires impact streams is a function of burn severity, fire intensity, burn
area, topography, soil properties, climate, and channel proximity. Wildfire can reduce soil
infiltration capacity and increase runoff and erosion. Based on field observations completed
during this BAER assessment, many of the high and moderate severity burns have a high
potential for surface erosion from overland flow that may enter headwater channels causing
sediment bulking that can be transported during subsequent high flow events. Potential postfire effects include: increased water temperature, peak flows and channel scour, surface erosion
and fine sediment delivery, and landslides and debris flows. Fire effects to fish and habitat are
expected to be the greatest in the next few years and to diminish to pre-fire levels within 7 to 10
years. Some of the effects such as increased large wood inputs, fresh bedload and gravel
could positively affect aquatic habitat.
With the exception of Beaver Creek, fish bearing tributaries in the Carlton Complex did not
suffer a large percentage of moderate to high burn severity. Sediment from post fire effects will
likely affect ESA listed fish migrating through the lower Methow River as a result of sediment
delivery from steep non-fishing bearing streams. Delivery of fine sediment from debris flows to
the Methow and Okanogan Rivers from the Carlton Complex has already occurred. The
greatest impact of this will be to spawning areas in Beaver Creek and the mainstem lower
Methow. Additional sediment delivery events within 1-3 years are likely. Roughly 15.5% of
riparian area along Beaver Creek burned, which will likely increase summer low-flow stream
temperatures and diurnal temperature fluctuation.
Burned Area Emergency Response treatments that reduce fine sediment delivery, restore
natural drainage patterns and allow for large wood movement and or accumulation in fish
bearing streams and the mainstem Methow are expected to benefit ESA listed spring Chinook,
steelhead and bull trout.
I.




OBJECTIVES
Identify fisheries values at risk
Assess how overall changes to soil and watershed function caused by the fire that may
affect critical fisheries values
Recommend non-emergency treatments to reduce the risk to fisheries values
Identify possible long term treatments to aid habitat recovery and reduce impacts of
future events.
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II.
ASSESSMENT METHODOLOGY
Information for this assessment is based on a review of relevant literature, habitat and other
field inventory information, and post-fire reconnaissance completed on September 5-9, 2014.
Species occurrence is based on surveys conducted prior to the Carlton Complex Fire.
III.
CRITICAL FISHERIES VALUES AT RISK
Carlton Complex burned 256,108 acres within the Methow River subbasin (HUC 5) and the
Okanogan River subbasin (HUC 5). Anadromous fish bearing waters within the fire perimeter
include the Lower Methow River, Bear Creek, Beaver Creek, Libby Creek, Gold Creek, Black
Canyon Creek, the Okanogan River, and Loup Loup Creek.
The lower Methow River, from rivermile (RM) 34 to the confluence with the Columbia River is
within the area of affect by the fire. It is also going to be susceptible to longterm post fire affects
from debris flows and sediment input from seasonal and perennial tributaries adjacent burned
slopes. This reach of the Methow River is used by ESA threatened Upper Columbia River
steelhead and summer Chinook (not ESA listed) for pre-spawn holding, spawning, juvenile
rearing and migration. This area is also a critical migration corridor for spring Chinook as adults
migrate to the upper watershed for spawning and juveniles outmigrate to the Columbia River
and Ocean. ESA listed threatened Bull Trout use the lower mainstem Methow for rearing,
foraging and migration. Their entire spawning habitat is located outside of areas affected by the
fire. Pacific Lamprey rely on the lower Methow River for rearing and migration. Specific impacts
to Pacific Lamprey are difficult to predict because population dynamics and distribution with the
subbasins is relatively unknown.
The Okanogan River is designated critical habitat for UCR steelhead, which primarily use it as a
migration corridor with Summer Chinook and Sockeye. The mainstem Okanogan River
exceeds suitable temperatures for most salmonids during low flow summer months. This favors
ocean-type life history strategies and has contributed greatly to the extirpation of viable spring
Chinook populations within this basin.
5
Figure 1. Illustrates the ESA-listed Fish Distribution within the area of fire effect. Upper
Columbia spring Chinook, Upper Columbia Summer Steelhead and Columbia River Bull Trout
are present in the Methow Subbasin. Only Columbia River Steelhead are present in the
Okanogan Subbasin.
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IV.
FISH SPECIES & GENERAL LIFE HISTORIES
a. Upper Columbia spring Chinook (Oncorhynchus tshawytscha)
Species Legal Status: ESA-Listed Endangered
General Life History: Spring Chinook adults begin returning from the ocean to the
Methow subbasin from April through July. These fish commonly hold in freshwater tributaries
until spawning occurs in the late summer, peaking in mid to late August. Juvenile spring
Chinook emerge from redds in gravel substrate in February and March. After one year of
rearing in freshwater (stream-type) the fry begin to change into smolts as they prepare to
migrate to the ocean during spring of their second year of life. Most Upper Columbia spring
Chinook return as adults after two or three years in the ocean (Figure 3).
The majority of spring Chinook spawning in the Methow subbasin occurs
upstream of the area affected by the Carlton Complex fire. Most adult spawners should have
been upstream of the area affected by the fire directly and the ash and debris flows which
occurred in August. Spawning is concentrated in the mainstem upper Methow River and its
largest tributaries: the Chewuch River and Twisp River. Occasional spawning may occur in
Gold Creek and at the smaller tributary confluences with the Methow River. Spawning in these
areas should considered rare occurrences, constituting approximately .1% of the basin wide
spawning annually. Spring Chinook do not currently spawn or rear in the Okanogan River.
The spring Chinook life stages and habitats most likely to be impacted by the
immediate fire effects and subsequent increased fine and coarse sediment loading will be
juvenile and adult migration habitat and juvenile rearing habitat in the lower mainstem of the
Methow River and fire affected tributaries. These acute effects could last for 1 to 3 years.
Spring Chinook spawning habitat is generally not found in the fire affected area. Positive effects
from the fire include habitat benefits from increased in stream wood, bedload, and gravel
recruitment.
b. Columbia River Steelhead (Oncorhynchus mykiss)
Species Legal Status: ESA-listed Threatened
General Life History: Adult steelhead return to the Columbia River in the late summer
and early fall then often hold for long periods of time in mainstem Columbia reservoirs or low in
tributaries like the Methow until they move to spawning areas in April and May the following
year. Spawning typically occurs in the late spring. Depending on water temperature, eggs will
incubate in the gravel for around 30 days. Fry emerge in June through July depending on water
temperatures and spawning dates. Juvenile steelhead generally spend one to three years
rearing in freshwater before migrating to the ocean, but have been documented spending as
many as seven years in freshwater before out-migrating (Figure 3).
Steelhead are generally classified as stream-type species which rear in the freshwater
for a year or longer, making fish in the lower mainstem susceptible to stress from increased
turbidity and fine sediment in the river. It is assumed that dramatic increases in fine sediment,
without associated coarse organic and inorganic material, will negatively impact juvenile and
7
adult migration and juvenile rearing habitat. However impacts from fine sediment delivery will
largely be dependent on the magnitude, timing and duration of runoff events. Dramatic
increases in turbidity will likely be short duration with diminishing return through successive
years of spring runoff and recovery. Increases in large wood, and gravel and rock could
provide favorable habitat for adult and juvenile steelhead.
Figure 2. Spawning ground survey data from 2005 through 2012 illustrates the average
annual percentage of steelhead redds for the Methow subbasin that are in the fire affected area.
Sediment impacts to spawning habitat are predicted to be the greatest in Beaver Creek and the
mainstem Lower Methow River. On average 5% of the basinwide spawning occurs in Beaver
Creek and 12% in the lower mainstem Methow River. Within the fire affected area in the
Okanogan subbasin only Loup Loup Creek contains spawning UCR Steelhead.
c. Bull Trout (Salvelinus confluentus)
Species Legal Status: ESA-listed threatened
General Life History: Bull trout in the Upper Columbia basin exhibit both resident and
migratory life-history strategies; resident bull trout complete their entire life cycle in their natal
stream, on the other hand migratory bull trout migrate to larger systems to rear. Bull trout
typically spawn in the fall in cold, clean, low gradient headwater streams with loose clean gravel.
Throughout all life stages, bull trout are found in streams where water temperatures remain
below 15°C and have complex forms of cover including large woody debris, undercut banks,
boulders and pools. Migratory bull trout spawn in tributary streams where juvenile fish rear one
to four years before migrating to either a lake (adfluvial form) or larger river (fluvial form).
8
Migrating bull trout have been observed within spawning tributaries as early as the end of June,
spawning occurs in mid-September to late October (Figure 3).
There are no documented bull trout spawning areas in the Carlton Complex affected
area. Bull trout have not been found in the Okanogan watershed, although historically they may
have occurred there. The mainstem Methow is a migratory corridor for bull trout and is used by
large migratory bull trout as foraging habitat for much of the year. Adult bull trout are
piscivorous and are found in the fire affected reaches of the mainstem Methow for much of the
year. Beaver Creek is the only tributary in the Carlton Complex that has documented resident
bull trout, although they have not been observed there for several years.
Bull trout are susceptible to competition and interbreeding with other non-native char
species such as brook trout.
Figure 3. Illustrates the life stage and timing within the fire effected tributaries and Lower
Methow River. Timing of runoff events and increased sediment loading have the potential to
affect different life stages ESA populations. Note that spring Chinook and Bull Trout spawn
upstream of the area affected by the Carlton Complex Fire.
d. Pacific Lamprey (Lampetra tridentate)
Species Legal Status: Species of Concern
General Life History: After spending one to three years in the marine environment Pacific
lampreys cease feeding and migrate to freshwater between February and June. They are
thought to overwinter and remain in freshwater habitats for up to one year prior to spawning.
Their preferred spawning habitat is similar to salmon; in freestone gravel bottomed streams, at
the upstream end of riffle habitat typically above suitable larvae rearing habitat. Spawning
occurs March through July depending upon location within the range. Ammocoetes drift
downstream to areas of low velocity and fine substrates where they burrow, grow and live as
filter feeders for 2 to 7 years and feed primarily on algae. Several generations and age classes
of ammocoetes congregate in high densities that form colonies. Ammocoetes are relatively
immobile. Metamorphosis to macropthlamia (juvenile phase) occurs gradually as they develop
eyes, teeth and become free swimming. Outmigration of juveniles to the Pacific Ocean occurs
between late fall and early spring.
9
Lamprey ammocoetes are found in fine sediments along the mainstem Methow River within the
area affected by the Carlton Complex fire. Distribution in the Okanogan River is unknown.
e. Other Affected Fish Species
The post fire effects from the Carlton Complex fire have the potential to affect other important
recreational fisheries, forage fish and non-game fish species.
Beginning in 1997 the Yakama Nation began a Coho reintroduction program in the Methow
subbasin. Coho were extirpated from the Methow River and its tributaries in the mid-20th
century after an impassible dam was constructed near the confluence with the Columbia River.
Coho tend to be tributary spawners that are commonly found in Gold Creek, Libby Creek,
Beaver Creek and side channels of the mainstem Methow. Coho have been extirpated from the
Okanogan subbasin.
Summer Chinook spawn throughout the mainstem Methow and Okanogan subbasins. Unlike
their close relative, the spring Chinook, summers exhibit an ocean-type life history pattern, out
migrating to the ocean during the first year of life. They are not considered at risk of extinction
in the near future. Summer Chinook adult holding areas and spawning areas are found in
reaches of the mainstem Methow affected by the fire and adult summer Chinook were likely
impacted by the mid-August 2014 ash and debris flows.
The Okanogan River provides a critical migration corridor for Sockeye returning to the Canadian
Okanagan lakes. Due to cooperative intergovernmental and public utility water management
agreements the Sockeye runs have supported sufficient natural origin progeny to warrant robust
commercial and recreation fisheries. These fish exhibit an ocean-type life history and spawning
habitat is located upstream of the burn area therefore overall impacts to the population are
expected to be minimal.
Native Westslope Cutthroat and rainbow trout are found throughout the mainstem Methow River
and the almost all tributaries. Fire effects to these species/races will be similar to those that will
be experienced by steelhead.
Eastern book trout are a non-native species which was planted extensively in small streams and
lakes for recreational fisheries on National Forest, state and private lands. They have been
shown to compete vigorously with native resident salmonid populations for space and forage
year-round. Additionally, they pose a significant threat to Bull Trout through interbreeding
Figure 1. this illustration depicts ESA-listed fish use within the Carlton Complex Fire affected
watersheds.
V.
FIRE AFFECTED WATERSHEDS AND SUB-WASTERSHED
DESCRIPTIONS
a. Lower Methow River
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The Methow River drains nearly 1,890 square miles (1,152,000 acres) and flows
southward for more than 80 miles through western Okanogan County before emptying
into the Columbia River near the town of Pateros. About 89% of the subbasin in public
ownership: U.S. Forest Service, WDFW, DNR and BLM. The remaining 11% is privately owned
and is predominately situated in the valley bottoms.
About 12.8% of the Methow Subbasin burned in the Carlton Complex Fire. Even more
was consumed in the Falls Creek Fire and the Little Bridge Creek Fires of 2014. The ladder two
fires burned entirely on USFS property, therefore are outside the scope of analysis for this
report. In the Carlton Complex Fire about 4% of the Methow subbasin was burned at moderate
to high fire severity (Table 2). The Methow River has been impacted by post fire ash and debris
flows that occurred following high intensity rain fall over the burned area. Beaver Creek, Frazier
Creek, Benson Creek, Canyon Creek, Leecher Creek, French Creek and Cow creek all
delivered massive quantities of fine sediment to the main stem Methow and will continue to do
so for several years. Following the debris flows the water was extremely turbid from about RM
34 to the mouth and into the Columbia River. The debris flows also delivered flotsam from
damaged houses, vehicles, and shops in the form of fuel tanks, pressure tanks etc. Following
the debris flows over 7,000 lbs. of this flotsam has been removed from the Methow by
volunteers. There will be a continued need for this type of debris removal from the river.
At the time of the flooding adult summer Chinook were holding in the mainstem river and were
likely impacted by the increased fine sediment load. Pacific lamprey ammocoetes rear in fine
sediments along the channel margins of mainstem Methow and were likely impacted by
deposition of fine sediments. The Bureau of Reclamation received anecdotal reports of dead
suckers and salmon near the Leecher Creek debris fan following the flooding. High fine
sediment loads could affect steelhead spawning success in the spring of 2015.
b. Bear Creek
The Bear Creek sub-watershed is 11,547 acres; 50% of the sub-watershed burned with about
13% of the burn being moderate to high severity (Table 2). Bear Creek enters the east bank of
the Methow River around RM 47. The lower 2.9 miles of the creek flow through private
residential and agricultural lands. The upper reaches are on WDFW and USFS lands. Juvenile
spring Chinook salmon and juvenile steelhead/rainbow trout have access to the lower 0.18 mile
of the creek where they encounter the first of a number of culvert barriers. Upstream passage
is blocked by low flows from irrigation diversions and by barriers created by 2 irrigation canal
crossings and multiple road crossings. Non-native brook trout are found above barrier road
crossings in the upper reaches.
The fire burned in the headwaters of Bear Creek with low to moderate intensity about 4 miles
upstream of the confluence with the Methow. Noticeable effects to fish habitat from the fire are
not expected.
c. Beaver Creek
Beaver Creek sub-watershed is 70,932 acres in size and enters the mainstem Methow
at RM 34. The watershed was 42% burned by the fire and 12% of the fire is moderate to high
fire severity (Table 2). Most of the moderate and high severity burned area is in Frazer Creek, a
11
tributary to lower Beaver Creek. The lower 6 miles of Beaver Creek flow through private lands
that are used mainly for growing irrigated alfalfa, mixed hay and for livestock production. Debris
flows from Frazer Creek have dramatically impacted the lower 2 miles of Beaver Creek. Dead
rainbow/steelhead trout and sculpin were observed immediately following the fire and again
following ash and debris flows created by convective storms in mid-August.
Juvenile Spring Chinook salmon can be found in low numbers in the lower 2 miles of
Beaver Creek. Steelhead spawn and rear on the lower 8 miles of Beaver Creek. Bull trout are
found in extremely low numbers in the upper watershed and are at high risk of extirpation from
the watershed. Brook trout populations in the upper watershed are robust and present a major
threat to bull trout populations in Beaver Creek. Re-introduced coho salmon also are beginning
to recolonize lower Beaver Creek.
Forty percent of riparian areas in Beaver Creek burned in the fire; 16% of the riparian
burn was moderate to high severity. Prior to the fire, warm summer water temperatures were
an issue in lower Beaver Creek. This loss of riparian shade will likely increase water
temperatures until vegetation regrows to provide shade. Riparian areas are already resprouting vigorously and are expected to recover quickly. The extent of riparian area burned in
Beaver Creek is one of the larger Carlton Complex fire effects to fish (Table 1 and Table 2).
In the last 10 years salmon and steelhead recovery efforts have been applied
extensively to Beaver Creek to improve instream flows, re-establish fish passage at roads and
irrigation diversions, improve habitat complexity, protect riparian areas, aquire conservation
easements and restore beaver populations. These projects appear to be functioning well,
providing favorable channel bedform and complexity habitats. The Old Schoolhouse Fish
Habitat Enhancement Project was complete by the Yakama Nation’s Upper Columbia Habitat
Restoration Project in 2013. This project consisted of 12 engineered log structures, channel
realignment and development of a spring fed side channel. All work elements associated with
this project survived the Carlton Complex Fire on July 17 and the Debris flows which occurred
on August 13, 2014. The large wood structures racked transient debris, increased floodplain
inundation and efficiently attenuated the streams energy.
The Upper Beaver Creek Fish Habitat Project was also completed in 2013 by the Methow
Salmon Recovery Foundation. It consists of a channel realignment, large wood habitat features
and irrigation headgate improvement at the Batie Diversion. The project area was burned over,
but burn intensities were low in proximity to this project and survived well. Sediment sluicing
structures installed in the diversion are working well. The piped canal is currently turned off due
to fire damage directly to the pipe. Damage to the diversion structure appears to be minimal,
though we expect continued maintenance to be required while increased sand and fine
particulate sediment delivery persists.
d. Frazer Creek
Frazer Creek enters Beaver Creek 2.7 miles above the confluence with the Methow
River. Juvenile steelhead likely use the lowest stream segment of Frazer Creek for rearing.
Upstream fish passage is blocked at the first irrigation diversion 0.3 miles upstream of the
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Beaver Creek confluence. Above this, many private driveways seasonally interrupt fish
passage. Brook trout were found in the middle reaches of Frazier Creek prior to the debris
flows in mid-August. It is unknown if there is a seed source for Brook Trout in the unaffected
upper subwatershed. Several anthropogenic features significantly impair ecological function in
Frazer Creek. Washington State Highway 20 and utilities constrict much of its historic
floodplain. Due to channel aggradation the road surface elevation is currently at or below the
low flow water elevation. This is causing the highway cut bank to capture all of Frazer Creek’s
water and channel it down the roadway. Residential homes, barns and outbuildings also
occupy portions of the lower three miles of floodplain. Additionally there are several culverts
and bridges which lock the channel in place and require debris removal from the stream to
function properly.
e. Benson Creek
Benson Creek is a 24,266 acre watershed that enters the Methow River at RM 32.5. About
36% of the watershed was burned and 44% of the burn area was moderate to high severity
(Table 2). Due to topographic and hydrologic conditions there is no anadromous fish use in
Benson Creek. Benson Creek flows through upper Finley Canyon and into a series of
reservoirs which were stocked with Brown trout (Salmo trutta), a non-native piscivorous
salmonid species. Two of these reservoirs breached and two more were damaged during the
mid-August storms, causing massive amounts of water and debris to reach the Methow River. If
the adfluvial non-native fish made it to the Methow they should be eradicated as expeditiously
as possible. Further research and monitoring should be conducted to assess the likelihood of
Brown Trout survival.
f. Black Canyon Creek:
Black Canyon Creek joins the Methow River at RM 8.1 and has a drainage area of 15,856
acres; 35.2% of the watershed burned and 9% of the burn was at moderate to severe intensity
(Table 2). UCR steelhead spawn in the lower 0.4 miles of Black Canyon Creek. Black Canyon
Creek has an impassable falls at RM 3.5. Due to the small amount of the watershed that
burned at increased intensities we do not expect much impact to resident or anadromous fish
species.
g. Squaw Creek
Squaw Creek is 10,169 acres in size. Approximately 44% burned and 14.2% was moderate to
high severity burn (Table 2). A steep gradient confluence with the Methow blocks fish access.
There is a private fish hatchery at creek mile 3. This hatchery will be very susceptible to debris
flows and flooding until ground cover recovers. Efforts should be made to decrease the chance
of accidental release to the Methow River. The creek is known to have some native and nonnative Brook Trout upstream of the hatchery.
h. Gold Creek
The Gold Creek drainage is 56,881 acres and 12% was burned – 2.3% burned at medium to
high severity (Table 2). Gold Creek enters the Methow River from the east at RM 21.8. Much of
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the drainage has been managed for timber harvest, livestock grazing and recreation (USFS
1996b). The lower reaches of the mainstem and South Fork Gold Creek are privately owned.
Roads parallel the major streams in the drainage and affect aquatic habitat (USFS 2000f).
Steelhead, spring Chinook and bull trout spawn in the watershed. We do not anticipate
significant post-fire impacts to these fish due to the small percentage of the sub-watershed that
burned at increased intensities.
i. Libby Creek:
The Libby Creek drainage contains 25,866 acres – 2.4% of the watershed burned and 2.3% of
the burn is at moderate to high severity (Table 2). Libby Creek enters the Methow River at
RM__. UCR steelhead and resident populations of cutthroat and rainbow trout inhabit the
Lower 6 miles of Libby Creek. We do not anticipate significant post-fire impacts to these fish
due to the small percentage of the sub-watershed that burned with high severity/intensity.
j. Okanogan River
The Okanogan River is approximately 115 mi long and originates in southern British Columbia.
Listed fish and fish species of concern in the U.S. portion of Okanogan River include UCR
steelhead, summer Chinook salmon and sockeye salmon. The lower reach that was affected by
the fire is used as a migration corridor for the salmonid species. Loup Loup Creek provides the
only suitable spawning habitat in the fire affected reach of the Okanogan watershed. Pre-fire
ecological concerns for fire affected area include elevated stream temperatures, increased fine
sediment loads, and reduced habitat complexity (UCSRB RTT Revised Biological Strategy,
2014)
The greatest impact to the Okanogan River will be predicted increased sediment input from
Chilliwist Creek. Chilliwist Creek is 26,594 acres; 64% of the watershed burned and 25%
burned at moderate to high intensity (Table 2). Following the fire high intensity rain storms
caused debris flows and mud to flow down the creek and towards the Okanogan River. Most of
woody debris, cobbles and gravels settled out on the large alluvial fan, however increased
surface flows contributed significant fine sediment to the Okanogan River. Overall fire and postfire impacts to UCR steelhead habitat in the Okanogan river are expected to be minimal.
k. Loup Loup Creek:
Loup Loup Creek is 14,597 acres; 31.7% of the watershed burned and 4.1 % of the burn was
moderate to high severity (Table 2). UCR steelhead are the only listed species that are found in
Loup Loup Creek. They are recolonizing the creek in response to two culvert barriers near the
mouth that were replaced with a bridge in 2012. The main ecological concerns for Loup Loup
creek are reduced stream flow, high sediment loads, reduced habitat complexity and reduced
riparian condition. Some habitat impairments will be alleviated by increased wood and bedload
recruitment predicted as post fire affects.
14
While 31.7% of the Loup Loup watershed burned only 4.1% of Loup Loup Creek burned at
moderate to high severity. Adverse effects to habitat in Loup Loup Creek are expected to be
minimal.
Name
Methow River Subbasin
Bear Creek
Beaver Creek
Benson Creek
Texas Creek
Libby Creek
Gold Creek
McFarland Creek
French Creek
Squaw Creek
Black Canyon Creek
Okanogan River Subbasin
Loup Loup Creek
Chiliwist Creek
HUC Size
(Acres)
% Burned
% Med-High
Burn
1,152,000
12.8%
3.9%
11,547
70,932
24,266
20,446
25,866
56,881
25,769
19,392
10,169
15,856
50.4%
42.5%
36.0%
73.4%
2.4%
12.0%
75.8%
84.0%
44.3%
35.2%
13.1%
12.0%
44.1%
23.4%
40.0%
2.3%
18.7%
28.5%
14.2%
9.0%
5,248,000
1.5%
0.3%
14,597
26,594
31.7%
63.7%
4.1%
25.3%
% Federal
Land
61.1%
77.5%
87.8%
17.5%
92.0%
97.3%
42.0%
18.1%
96.7%
99.3%
3.2%
8.2%
ESA listed
Species (Y/N)
Perrenial
Stream (Y/N)
Y
Y
Y
Y
N
N
Y
Y
N
N
N
Y
Y
Y
Y
N
Y
Y
Y
N
N
Y
Y
Y
Y
N
Y
Y
Table 1. This table illustrates the relative size of each watershed or subwatershed and the
relative amount of burned area and increased burn soil severity related to moderate and high
burn intensities. This can be used to generally predict the basins response to storm events and
it capacity to buffer cumulative effects downstream. It should be noted that the US portion of
the Okanogan River Sub-basin is about 1,600,000 acres in size.
VI.
POST FIRE AFFECTS
a. Riparian Shade and stream temperature:
Increased stream temperatures can occur following wildfires when riparian vegetation is
reduced in moderate and high intensity burns. This can result in increased solar radiation and
changes in streamside microclimates until enough riparian vegetation can again shade stream
channels (Brown and Krieger 1970; Dwire and Kauffman 2003). Changes in water
temperatures can be especially problematic during the summer, when solar radiation levels are
highest and streamflows are low (Beschta et al. 1987). To evaluate potential changes in to
water temperature we looked at the percent of riparian corridor which burned with moderate to
high severity. Using ArcGIS with the NHD streams layer and the corrected soil burn severity
map we calculated the percent of riparian vegetation burned at varying intensities and percent
of total perennial stream length by subwateshed. .
The Beaver Creek sub-watershed (inclusive of Frazer Creek drainage) experienced the greatest
loss of riparian vegetation cover. Approximately 41% of the 36 mile long riparian drainage
network burned with about 16% of that burning at moderate to high severity (Table 3). Other
fish bearing waters within the Methow and Okanogan subbasins did not experience significant
riparian vegetation loss.
15
Water temperature studies after wildfires in the Bitterroot River drainage in Montana found that
one month after fire and in the subsequent year, increases in maximum water temperatures
within burns were 1.4–2.2 oC greater than those in unburned reference sites (Mahlum et al.
2011). The greatest differences between reference and burned sites occurred during low flow in
July and August. Even after seven years, maximum stream temperatures had not returned to
pre-fire conditions. This suggests that until enough riparian vegetation recovers in the Beaver
Creek drainage the stream will be susceptible to increased solar radiation and warmer low flow
summer water temperatures.
Methow River Subbasin
% Riparian % Riparian
Beaver Creek
Libby Creek
Gold Creek
Black Canyon Creek
Stream Length
(Miles)
36
19
22
8
Area
Burned
41%
32%
4%
3%
Burn ModHigh
16%
2%
0%
0%
Okanogan River Subbasin
Loup Loup Creek
20
14%
1%
Table 2. Describes the post-fire riparian conditions of anadromous fish-bearing streams in the
Methow and Okanogan Subbasins.
Figure 4. Example of moderate burn severity in riparian area in Beaver Creek.
b. Stream Nutrients
Increased nutrients (nitrogen, ammonium, and potassium) have likely eroded into streams as
lighter ash washed from banks and adjacent burned slopes after initial rains in August 2014.
Nutrient loading typically increases following a wildfire due to the rapid mineralization and
dispersion of plant nutrients. Increased nutrients may have a short-term positive benefit to
16
downstream aquatic organisms such as plankton and algae, resulting in more robust food base
for benthic macro-invertebrates and intern, juvenile rearing salmonids, lamprey ammocoetes
and adult resident trout species.
c. Surface Runoff and Erosion
The extent to which wildfires impact streams is a function of burn severity, fire intensity, burn
area, topography, soil properties, climate, and channel proximity (Baker, 1988; Beschta, 1990;
DeBano et al., 1998; Robichaud,
2000). Wildfires can reduce soil
infiltration capacity and increase
runoff and erosion. Based on field
transects completed during this
BAER assessment, many burn areas
of the high and moderate severity
experienced increases in soil
hydrophobicity and potential for
surface erosion, mass wasting and
debris flows. Absent of significant
water accumulation adjacent hill
slopes will be susceptible to dry ravel
due to extreme topography and loose
aggregations of material. Because of
this we anticipate accelerated soil
erosion and sediment delivery in
Figure 5. Culvert Failure
localized areas until enough vegetation recovers to stabilize source slopes; likely with 2 to 5
years. These effects are
especially likely in Beaver
Creek, Frazer Creek, Upper
Finley Canyon, Benson
Creek, Texas, Cow, and
Chiliwist Creek, which
sustained large areas of
moderate to high fire
severity. Downed wood and
course material in upslope
areas and small depressions
will reduce the erosive
energy though significant
events are will easily
overwhelm roughness and
storage capacities. Many
severely burned areas
Figure 6. Ash and Sediment Flows in Beaver
exhibit steep, headwall and
Creek
upper watershed gorge
topography which will efficiently transport material directly to valley bottoms, tributaries and
mainstem systems.
Some streams with adequate roughness features may be able to temporarily store some fine
sediment. However many streams experience chronically confined channels which efficiently
17
transport material to lower gradient response reaches where it will likely settle out of
suspension. Spawning gravel quality may decrease in localized areas depending the
magnitude and duration of the sediment pulse that enters the channel and the streams storage
ability. Pool volume may also decrease until sustained high flows re-scour pools and transport
the fine sediment downstream.
Localized inchannel sediment may increase for several years as streamside trees fall and
streambanks erode as flows move around fallen debris. Zelt and Wohl (2004) found stream
channel width increased in burned streams due to increased bank erosion and sediment
movement, which often causes stream bed agradation in response reaches.
The principal post fire impact to fisheries resources is projected to be fine sediment transport
and deposition in the anadromous fish bearing tributaries and Lower Methow River. The
contribution of surface runoff to fine sediment transport and deposition is highly dependent on
storm variables such as location, timing, magnitude, and duration; as well as the watersheds
capacity to store water and sediment. The Methow River’s large volume and capacity for
sediment will attenuate the sediment impacts from ephemeral and perennial streams. Beaver
Creek and Frazier Creek however are likely to experience significant short term changes in
sediment and hydrologic condition.
i. Road and Fireline Contribution
Road concentrations within the Carlton Complex fire will alter the watersheds natural ability to
deal with precipitation events. Roads and culverts channelize runoff, unnaturally increasing
runoff energy and downstream affects. Further exacerbating the pre-existing road network
condition is approximately 152.6 miles of bull dozer line that was installed during fire
suppression activities (Table 3). Rehab of dozer line will be extremely important to minimize its
contribution to sediment runoff until vegetation recovers. Dozer line treatments include seeding,
water barring, replacing the berm, and increasing roughness with native woody materials.
Road densities are also going to increase quickly on private and DNR lands due to salvage
timber sales that will further destabilize slopes adjacent to many storm conveyance channels
(Reeves, et al 2006). These anthropogenic alterations to the hydrologic condition with the
subwatersheds are expected to have an adverse additive effect on sediment delivery and
recovery time throughout isolated portions of the burned area.
Private
46.9
Jurisdiction
State
58.7
Federal
47
Table 3. Miles of bull dozer line constructed during fire suppression activities by jurisdiction.
d. Mass wasting and Debris Flows
Mass wasting events are difficult to predict because they depend heavily on slope, soils,
vegetation, and individual or additive storm events. In general these are not an entirely
unnatural occurrence in post fire environments and fish populations are well adapted to dealing
with them. These events have the potential to transport large quantities of woody material and
18
fill to the valley bottom streams. Unfortunately, due to the fragmented nature of upper hillslopes
and valley bottoms, from infrastructure and road crossings over channels many of the positive
contributions to fish bearing streams will probably not be realized.
Previous and predicted future debris flows have the potential to affect fish health and habitat on
several temporal scales. Fine particulate delivery to the Lower Methow is expected to
significantly increase until the slopes with moderate to high burn intensities stabilize. This
stabilization is expected to occur relatively quickly through loss of hydrophobic soil properties
and vegetation establishment. Improvements to road drainage systems, mulching and bank
stabilization will all decrease the intensity and duration of increased turbidity events. Gravel,
cobble, boulders and large wood that reaches fish bearing streams is predicted to improve fish
spawning, rearing, and migration habitat. The duration of these improvements is highly
dependent on the size, mobility, location and orientation of the material as well as magnitude
and duration proceeding climatological events.
Figure 7. Convective storm induced debris flow adjacent Beaver Creek
Large Woody Debris
Most moderate and high intensity burn areas occurred in mid and upper slopes adjacent to
seasonal and high order perennial stream channels. This will likely limit increased wood
recruitment to the mainstem Methow and designated critical habitat waters within the larger
tributary systems. The one notable exception to this is seen on Beaver Creek, where there was
significant mortality to mature cottonwoods within the riparian corridor. We have observed a
dramatic increase in mainstem and tributary/floodplain wood loading caused by tree mortality,
increased runoff and flash flooding events. In general much of this wood was deposited in loose
aggregations close to the mean low flow stream margin along the Methow River and its
tributaries. Wood found in this configuration will likely be mobilized during spring runoff events
and transported downstream. Increased wood recruitment and retention in the Methow would
benefit channel bedform, channel complexity, adding allocthonous nutrients, and directly
provides rearing, cover and spawning habitat.
19
Modeled Peak Flows
To refine and validate field estimates of watershed response, 8 drainages within the fire
perimeter were selected for hydraulic analysis (Figure 3). Drainages were selected for modeling
based on the percentage of moderate and high soil burn severity, values at risk downstream,
and the observed response from recent thunderstorms on August 13th and 20th.
Data from the soil burn severity map were used to estimate peak flow using two different
hydrologic models. The Wildcat5 and Automated Geospatial Watershed Assessment (AGWA)
models were used for 8 selected drainages with significant amounts of private and state
lands. Wildcat 5 estimates peak flow and runoff volume from modeled storms at the outlet of
the modeled drainage. AGWA estimates peak flow, percent increase in flow, and sediment
delivery for the outlet, as well as for all channel segments upstream of the outlet.
Model results are not accurate for use as an estimate of absolute values for flow. Rather,
should be used to estimate the relative percent change in expected flows. Input to the models
included drainage characteristics, inherent soil conditions, changed soil conditions due to the
fire, and precipitation. The models were run using a 1 hr duration 25 year recurrence interval
storm, which for the fire area was determined to be 0.77” per NOAA Atlas 2 methodology. Both
models estimate storm runoff only, not base flow.
AGWA results are shown in Figure 3 and Wildcat5 in Table 4.
Table 4. Wildcat5 and AGWA Model Results for 25 year storm
Drainage
Beaver Creek above
Frazer
Benson Creek @
mouth
Canyon Creek @
mouth
Chiliwist Creek @
mouth
Cow Creek @ mouth
Frazer Creek @ Beaver
Ck
Leecher Creek @
mouth
Texas Creek @ mouth
Pre Fire
Q (cfs)
Wildcat5
Post Fire
Q (cfs)
Pre Fire
Q (cfs)
AGWA
Post Fire
Q (cfs)
%
increase
%
increase
33
424
1185
126
187
48
22
1,228
5529
3
65
2067
1
109
9264
4
78
1850
36
739
1941
36
436
1111
7
318
4317
15
220
1367
20
516
2510
57
677
1088
8
192
2297
18
144
700
10
302
2848
14
164
1071
Results for both the AGWA and Wildcat5 models for a 25 year 1 hour storm confirmed field
findings that several drainages are now particularly prone to increased flow events. Based
on the model results, subwatershed mod/high soil burn severity summary, subwatershed
topography, and evidence from storms during the middle of August, the areas of highest
likelihood of watershed response appear to be:

Frazer Creek
20

Benson Creek

Canyon Creek

Leecher Creek

Cow Creek

Chiliwist Creek

Three steep unnamed tributaries of the Methow River downstream of Black Canyon
Creek
All of these drainages have increased risk from runoff generated on burned hillslopes. Risks to
downstream values vary and depend on the location of the values specific to each
drainage. This determination highlights areas of concern, but does not exclude other areas
from consideration for emergency treatments. Other drainages also have the potential to
respond to precipitation events.
21
Figure 8. Thickness of blue stream segments represent percent difference in flow between
pre and post-fire conditions (thicker lines equate to greater increase in post-fire flows).
Based on field observations completed during this BAER assessment, many of the high and
moderate severity burns have a high potential for surface erosion from overland flow that may
enter headwater channels causing sediment bulking that can be transported during subsequent
high flows. Sediment delivery in a 25 year storm event will deliver anywhere between 3-21
tons/acre in high to moderate burn severity areas with a potential delivery of 1229 yd3/mile2 .
The majority of this material will likely affect ESA listed fish migrating through the lower Methow
River given most sediment delivery is expected from steep non-fishing bearing streams. With
the exception of a small percentage of bull trout that use the mainstem Methow for
rearing/overwintering, most ESA listed fish in the Methow are migratory and moving upstream to
more ideal spawning areas; pulses of sediment will be of short duration with minimized adverse
effects.
22
VII.
Treatment Recommendations
No emergency treatments have been identified specifically to protect fisheries resources.
However, fisheries resources could benefit from the effects of recommended treatments
designed to improve public safety and decrease risk to infrastructure from post fire effects.
Treatments, such as mulching and seeding, that are designed to decrease fine sediment
transport will benefit fish habitat throughout the watershed. Improvements to road drainage
networks through increased culvert capacity, hardened dips, out sloping roads,
decommissioning roads and construction of settling basins are expected to have a positive
effect on downstream sediment loading and decrease the risk of road prism failure. Road
failure has the potential to add significant fine sediment to streams, similarly to mass wasting
events and flash floods though without the benefits of bedload and wood debris. Culvert
replacements in fish bearing streams should be designed for upstream fish passage and be
designed to allow bedload and wood material to move downstream.
Increasing the capacity for material transport within the drainage network should be pursued.
Bottle necks like private driveway crossings, county road crossings and culverts which trap
material and require mechanical removal should be updated to allow natural transport. In many
cases this means installing bridges, oversized culvert or large box culverts to allow unfettered
large material transport.
Treatments which decrease floodplain capacity, channel capacity, channel roughness,
floodplain roughness, large
wood recruitment potential and
riparian vegetation should be
avoided. This is especially
important in fish bearing
streams and non-fish bearing
perennial streams. Some
examples of these treatments
which conflict with fish habitat
improvements include:
installation of undersized
culverts, point protection with
dykes, rip-rapping, wood
removal and riparian clearing.
Figure 9. Photo depicts cottonwood regrowth since from July 20, 2014 to September 8, 2014.
23
VIII.








IX.





Recommendations for Near and Long Term Recovery
Increase/encourage large wood recruitment and retention to mainstem Methow River
and fish bearing tributaries.
Restore natural floodplain function and channel dynamics within perennial fish bearing
streams. The need for this action is particularly evident in Fraser Creek where continued
floodplain constriction will likely produce large quantities of fine sediment.
Consider Brook Trout eradication in Frazer Creek in 2015. The recent flood events in
Frazer Creek have likely decimated brook trout populations and now may be the ideal
time to ensure complete removal. Further upstream investigation is necessary to
determine if there is a seed source for Brook Trout in this system.
Limit excessive fine sediment delivery to fish bearing streams but allow for bedload
materials to be transported. Bedload provides cobbles and gravels for spawning and
larger material for rearing habitat. Work with engineers to design anthropogenic features
which accomplish ecological and infrastructure objectives.
Riparian replanting and maintenance where weed invasions could impair native
vegetation recovery. This should be efforted in in fish bearing and perennial streams.
Improve irrigation diversion structures to accommodate increased sediment loads
predicted to affect stream conditions for the next 5-7 years. Additionally, fish screens
should be updated to improve function and decrease maintenance requirements.
Improve or reestablish fish passage at irrigation diversions and road crossings.
Remove and upgrade undersized culverts and bridges that routinely cause property
damage and require debris removal to function.
Monitoring Recommendations
Temperature monitoring in Beaver Creek
Sediment monitoring in spawning areas in Beaver Creek and lower Methow
Fish population recovery in Beaver Creek. Fish populations in the lower 6 miles of
Beaver Creek were likely severely reduced by recent flooding and debris flows.
Recolonization will likely occur quickly. A robust fish distribution data set was collected
in the years prior to the fire and provides a good opportunity to measure population
recovery following a major disturbance.
Fish Habitat Enhancement project performance should be monitored in Beaver Creek
and lower Methow River. Several major fish habitat projects were completed in 2012
and 2013 and were burned over by the fire. Comparing the recover y of these treated
areas to non-treated area could provide important information that could be used in
future project designs.
Monitor Beaver population recovery and effects on burned riparian corridors.
24
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25