Hydrology Report
Conner Creek Fish Passage Improvement Project
USDA Forest Service Region 5
Shasta-Trinity National Forest
Trinity River Management Unit (TRMU)
Prepared by: /s/ Mark S. Lancaster
CA Registered Professional Forester
Five Counties Salmonid Conservation Program
Northwestern California Resource Conservation and Development Council
Reviewed by: /s/ Fred S. Levitan
West Zone Hydrologist
Shasta-Trinity National Forest
June 15, 201
Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
I. Description of Proposed Project
The Five Counties Salmonid Conservation Program (5C)1 in cooperation and partnership with the Trinity
County Department of Transportation (DOT) proposes to replace the existing culverts on Conner Creek at
Red Hill Road (County Road 415) and Conner Creek Road (County Road 449). Red Hill Road is the sole
access and egress route for the Cooper’s Bar Estate subdivision and Red Hill Lake neighborhoods,
providing access to more than 100 private parcels and/or homes. It also accesses Forest Service Road
33N41 and the Hocker Meadow area, the main route to the upper elevations of the Conner Creek
watershed. Conner Creek Road is a dead end road that serves approximately 10 private parcels and
homes.
The project is located in Section 2 T 33N, R 11W MDBM. Crossing #1 is at milepost 0.06 on Conner
Creek Road and Crossing #2 is at milepost 2.4 on Red Hill Road (Figures 1-3). The project is located in
the Conner Creek-Trinity River 7th-field subwatershed and Conner Creek is a fourth-order perennial
tributary to the Trinity River (Table 1).
Table 1. Conner Creek Fish Passage Improvement Project watershed hierarchy
HUC4 (Subbasin)Level
18010211Code
Trinity River
HUC5 (Watershed)
1801021109
Canyon Creek
HUC6 (Subwatershed)
180102110803
Lower Canyon Creek
HUC7 (Drainage)
18010211080306
Conner Creek-Trinity River
Both stream crossings create backwater conditions during moderately high flows (~Q15); the roads
overtop during larger flows (Q18 and Q43) and prevent upstream migration for salmonids and resident trout
during nearly all flows. The proposed project will replace the existing culverts with structures designed
to allow fish to migrate upstream, convey the Q100-year storm flows and allow improved downstream
transport of bedload, wood and debris. While the project was recognized as a priority following the
Trinity County Migration Barrier Inventory (conducted between May 2001 and June 2002) of stream
crossings on county roads (Taylor, 2002), the need for the project increased following the 2008 Eagle Fire
which burned the upper 41% of the Conner Creek watershed within the Eagle Inventoried Roadless Area.
The project is proposed because the existing crossings are inadequate to meet federal, state and local
goals, policies and objectives for threatened and endangered species conservation and recovery. The
crossings fail to meet water quality objectives (refer to Section IV). Specifically, the current stream
crossings are deficient because:
 They prevent nearly all upstream migration of adult and juvenile salmonid fish species and the
outlet jumps at both crossings exceed 1+ feet, limiting juvenile salmonid passage during all
flows (Taylor 2002; refer to Figure 3);
 The existing offset baffles that line half of the concrete box culvert floor on Conner Creek Road
jam with debris and are ineffective at improving adult migration following larger storm flows
(Figure 3);
 Both stream crossings impede natural bedload, wood and debris transport;
 Both stream crossings have the potential to overtop and fail, cutting off access to over 100 private
parcels and access to public lands;
1
A non-profit program within the Northwestern California Resource Conservation and Development Council (RC&D);
refer to www.5counties.org for additional information.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
 Both stream crossings, if they were to fail, could yield 750-2,189 cubic yards (yd3) of sediment to
Conner Creek (5C DIRT Inventory, 2001; DOT 2011).
 The 2008 Eagle Fire in the upper portions of the Conner Creek watershed increased the potential
peak discharge of small to moderately large storms for the short and mid-term periods.
Additionally, the fire increased the potential for sediment, bedload and debris transport (USFS,
2008).
Figure 1. Project Location Map
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Figure 2. Crossing (#1 and #2) Locations
Figure 3 (photos above). Red Hill Road perched outlet and jump (left); Conner Creek Road
crossing offset baffle debris jam (center) and Conner Creek Road outlet jump (right).
Figure 4 (photos below). Multi-plate arch set on concrete abutments on a nearby comparative
watershed (Soldier Creek at Evans Bar Road). The left photo is similar to the proposed structure
to be installed on Red Hill Road, while a bridge similar to one installed on Little Browns Creek at
Roundy Road (right) would be installed on Conner Creek Road.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Conner Creek is designated as critical habitat for threatened coho salmon by NOAA’s National Marine
Fisheries Service (NMFS) and as a tributary to the Trinity River, it is designated as impaired by excess
sediment and siltation and excess water temperature under Section 303(d) of the Clean Water Act by the
State Water Resources Control Board. There is an EPA-approved sediment Total Maximum Daily Load
(TMDL) in place for the Mainstem Trinity River system (EPA, 1999). The five-acre project area and
stream crossings are located within designated Riparian Reserves under the Northwest Forest Plan
(NWFP) and the Shasta-Trinity National Forest Land and Resource Management Plan (Forest Plan), as it
lies within 300 feet of a fish-bearing perennial stream (Conner Creek). One acre of the proposed project
area (Conner Creek Road staging area) is outside of Riparian Reserves, but all proposed project activities
will meet the Aquatic Conservation Strategy Objectives. Additional details regarding application of all
applicable environmental laws and regulations are provided in Section IV below.
The proposed project would remove the 10-foot diameter corrugated metal culvert at Red Hill Road
(Crossing #2) and replace it with an 18-foot wide, embedded metal plate arch culvert. It would also
remove the 18-foot long, 6-foot tall, 14-foot wide concrete box culvert at Conner Creek Road (Crossing
#1) and replace it with a 24-foot wide by 7-foot tall bridge (14-foot wide travel way). Specific
information for each Crossing is provided below.
Red Hill Road (Crossing #2): The existing 10-foot diameter, 66-foot long corrugated metal (CMP)
culvert would be replaced with an embedded 18-foot wide, 12-foot tall, 70-foot long multi-plate arch
culvert set at a maximum 5% gradient (refer to Figure 4 for a similarly designed project in the Junction
City area). The new stream crossing gradient would be consistent with the average channel gradient in
the area of 5%. The project would not require the installation of headwalls, flared inlets/outlets or other
inlet/outlet controls, except for minor rock slope protection (RSP). This design minimizes the disturbance
to riparian vegetation outside of the road fill prism during construction. The increased road width could
eliminate the need for guard rails (to be determined by DOT engineering staff).
Figure 5. Red Hill Road Crossing (#2)
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
A Bailey bridge would be installed over the crossing once the road base and portion of the roadfill
material are excavated to allow for installation. The Bailey bridge will allow for full excavation of the
remaining roadfill, existing culvert and remaining construction activities while providing for one-way
traffic throughout construction. The excavation is expected to be approximately 22 feet wide at the
bottom and approximately 60 feet wide at the top and 70 feet long, with an average 12-foot depth.
Approximately 740yd3 of material would be excavated. The multi-plate arch structure would be
assembled within the excavation area and approximately 460yd3 of fill would be reincorporated into the
roadfill after the new structure is constructed. The roadfill slopes would be at reconstructed at the same
angle as the existing fill (1½:1). Spoils material would be stored the existing open, flat staging areas for
re-use in the project. Any excess material (~280yd3) would be stored at a pre-approved disposal site or
recycled at a DOT yard. All material will be stored in a manner to not deliver to a watercourse.
Approximately 20% (or 2 feet) of the bottom of the new arch crossing (~85yd3) would be embedded with
D5-D85 particle size engineered stream channel mix and a low flow channel would be shaped within the
crossing floor. The engineered streambed will be placed, the low flow channel shaped and the bed jetted
to seal the voids in the streambed material. Rock weirs/ribbons may be installed within the crossing to
define the low flow channel and provide grade control at 5%. A rock ribbon consisting of 1 to 2 ton
boulders would be set in the existing outlet pool for grade control and the pool would be backfilled with
engineered streambed mix and sealed. The rock ribbon would be set 6 inches below the designed
streambed elevation. The channel gradient from the downstream control point (tailwater control for the
outlet pool) to above the upstream rock ribbon would conform to the average 5% channel gradient in this
reach.
The new crossing would span the 12 to 14-foot active channel width as well as the 2-year channel width,
but would not have a 1:1.5 ratio associated with a stream simulation design project. The current crossing
(~79ft2 surface area) can convey less than the 20-year flow before it backwaters and requires active
management for removal of large wood debris accumulation at the inlet. The road overtops on the 43year flow and the new design (~144 ft2 surface area) would convey the 100-year recurrence interval flow
and provide for more efficient transport of bedload and debris.
While stream and groundwater dewatering would not be necessary during excavation of the roadfill
material (initial construction phase), surface water re-routing and groundwater seepage controls would be
installed during the subsequent removal of the existing metal culvert, installation of the multi-plate arch,
excavation and placement of two sub-grade grade control boulder ribbons and placement of the
engineered stream bed material. Dewatering and fish exclusion fencing placement would be conducted
consistent with BMPs and species relocation would be conducted by a qualified fisheries biologist. Fish,
if present, would be relocated to areas both upstream and downstream of the fish exclusion fencing (for
complete details on fish exclusion fencing installation and location and channel reach dewatering, refer to
the project Fisheries Biological Assessment and Evaluation). Channel dewatering should only be
necessary for 3 to 4 weeks.
Approximately 37 sapling sized trees (<1” diameter), 24 small trees (1” to 6” diameter), 12 medium sized
trees (6” to 12” diameter) and two larger big leaf maples (19” and 22” diameter) would be removed from
the road prism. Cores from two trees indicate that the older trees in the road prism are approximately 50
years old. Trees to be removed include white alder, big leaf maple, madrone, ponderosa pine, incense
cedar and Douglas fir. Other shrub/ground species to be removed from the road fill include wild grape,
English ivy, poison oak and small amount of native and non-native grass species. After installation of the
new crossing, replacement of the roadfill and shaping of the fillslopes native grass seed and shrubs/tree
species would be planted and mulched with rice straw, ground wood mulch or similar suitable weed-free
mulch material. Portions of the fill face would be armored with RSP and/or cobble-sized material.
Interim slope erosion control techniques such as silt fencing and large wood placement would be utilized
on fill slopes (refer to BMPs in Section V).
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Conner Creek Road (Crossing #1): The existing 6-foot tall, 14-foot wide, 18-foot long concrete box
culvert would be replaced with a pre-fabricated 7-foot tall, 16-foot wide, 40-foot long steel beam bridge.
The freespan width would be 24 feet, more than 1.5 times the active channel width of the reference reach.
The surface area of the new crossing floodplain is ~156 ft2 compared to the 70 ft2 floodplain of the
existing opening. HEC-RAS2 modeling indicates that the crossing would be able to convey the 100-year
peak flow (1,806 cfs) while the existing box culvert overtops at less than the 25-year recurrence flood
interval (885 cfs). Removing the offset baffles would reduce the potential for debris accumulation within
the crossing. The left bank would be in the current location of the existing wingwall. The right bank
would be excavated back sufficiently to widen the active channel width to 24 feet and provide clearance
for placing the new abutment. The new abutments would be 7 feet tall, 1 foot wide and 16 feet long.
These abutments would sit on a 3-foot wide footing placed on a 6-foot deep concrete keyway that is set
below the maximum scour depth.
Figure 6. Conner Creek Road (#1)
All excavation would be within the road prism and its associated toe slope. A “V” shaped low flow
channel would be formed using D5-D85 sized engineered streambed material that would have a 1-foot drop
from the edge of each stream bank to the center of the channel; representing an approximate 8.5% stream
bank gradient. The low flow channel would not conform to the riffle and run habitat immediately
upstream, but would maintain fish passage during low flows.
A detour bridge would be placed adjacent the existing roadway/culvert on the downstream end and the
approaches will conform to the road shoulders. Minor rock placement would be placed to transition the
approaches. Three alder trees may need to be trimmed or removed due to overhang near the existing
culvert but if retention is deemed safe and feasible, every effort to retain all or the majority of the trees
2
Hydrologic Engineering Centers River Analysis System; completed by Trinity County Department of Transportation
Engineering staff; March 2011.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
will be made. It is anticipated that the detour bridge would be needed for 1 to 2 weeks. There are no
underground or overhead utilities to be relocated.
After aquatic species relocation, temporary bridge and stream diversion (clean water bypass) installation,
the 3-foot wide, 6-foot deep, 16-foot long concrete footing (keyway) will be formed and placed in the
existing roadway directly behind the existing culvert’s left bank abutment (abutment will be left in place
as a support wall). This work will be completed outside of the active channel and there should be limited
potential for ponding of groundwater and delivery of roadfill material to the stream. A 1-foot wide, 7foot tall, 16-foot long abutment will be formed/placed atop the footing. A similar sized footing and
abutment will be excavated and constructed on the right bank. This will also require excavation of the
material between the right bank footing/abutment and the existing culvert (~120yd3). Once the footings
and abutments have cured, structural backfill will be placed (~40yd3) to fill the voids behind the
abutments and compacted with a manual whacker and/or other small equipment to compaction
specifications. The box culvert will be left in place for the duration of footing excavation/placement and
abutment construction. Once cured, the culvert will be excavated (with exception of the left bank
abutment) and removed to the equipment staging area or DOT yard. Partially grouted rock slope
protection (¼ to ½-ton boulders) will be placed at a 1:1 slope along the left bank wing wall for
stabilization and scour protection. Engineered streambed material (D5-D85 size) will be placed and jetted
to compaction in the crossing to form a low-flow channel (~20yd3), providing for fish passage at low
flows. A rock-ribbon grade control structure (1 to 2-ton) will be installed 6” below the designed
streambed elevation in the outlet pool area (already e-fished and dewatered). The outlet pool will be
backfilled with D5-D85 sized streambed mix (~23yd3) and jetted to compaction. A similar grade control
structure will be installed immediately upstream of the crossing. The rock slope protection/ribbons and
streambed will be installed from the roadway using an excavator or other heavy equipment. After
placement of all RSP and grade control, the pre-fabricated bridge deck will be set with a crane.
Dewatering would be necessary during excavation of the left wingwall, pouring of the left keyway and
footing, during demolition of the box culvert, excavation and placement of the two grade control
structures and construction of the new stream channel. Installation of fish exclusion fencing, species
relocation and dewatering would be consistent with BMPs. Channel dewatering would be necessary for
1-2 weeks.
Guardrails would be installed prior to removal of the detour bridge. Paving would be completed at a later
date. The entire construction window is estimated at 8 weeks.
II. Field Evidence
Conner Creek Watershed Scale
Conner Creek is a fourth-order perennial tributary to the Trinity River that flows through moderately
steep terrain in a northeasterly direction. Elevations range from 1,450 feet at the mouth to 5,507 feet
northeast of the Hayfork Divide. The majority of the watershed is within the Eagle Inventoried Roadless
Area, with the lower part of the watershed located in rural residential areas of Junction City. Extensive
mining activity in the lower reaches of Conner Creek modified the historic channel and altered conditions
at the confluence with the Trinity River.
A Stream Condition Inventory (SCI) survey was completed by the USFS fisheries staff on a 2,290 foot
reach upstream of Crossing #2 in 2007 (SCI records, Weaverville Ranger District). The 2007 SCI located
36 pieces of large woody debris (LWD) in the survey reach (equates to 83 pieces of LWD/mile). All
pieces were at least 16” dbh, but only three were ≥ 50 feet in length (indicating non-functioning LWD
recruitment). It is anticipated that LWD recruitment will increase over the next decade as a result of the
Eagle Fire and the existing crossings on Red Hill and Conner Creek Roads presently require the removal
of larger LWD from the channel to avoid plugging the culverts.
In 2008, the Eagle Fire burned upslope of Red Hill Road, resulting in the loss of canopy and ground
cover; a reduction in evapotranspiration rates; an increase in surface runoff and exposure of soil to
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
erosion; a reduction of soil water infiltration; and an expected increase in overland flow and peak stream
flows (Neary et al 2005, Swanston 1991). These changes will result in an overall increase in erosion and
sedimentation at the watershed scale (erosion hazard rating is high; 2009 Burnt Ranch-Soldier Creek
Watershed Analysis). Following the Eagle Fire, the Iron/Alps Hydrological Resource Assessment (HRA)
was completed as part of the Burned Areas Emergency Response (BAER) assessment of the Iron/Alps
BAER assessment (USDA Forest Service, 2008). The assessment indicated that 41% of the 7th-field
Conner Creek subwatershed had moderate to low severity burning with high severity burning near the
ridgetops (USFS, 2008). The HRA modeling also predicted a peak increase in 10-year recurrence runoff
rates of 1.5 to 1.8 times compared to pre-fire conditions in the subwatershed. The 2009 Burnt RanchSoldier Creek Watershed Analysis (USFS, 2009) indicated that while fire impacts to hydrology are
expected to recover to normal within 10 years, road impacts are permanent unless roads are
decommissioned or restored to a hydrologically neutral state.
In addition to the Forest Service studies, the 5C Program has conducted photo monitoring of flows and
debris movement within the project area since 2001 (refer to Figure 3). During empirical monitoring
from winter 2008/2009 through present, higher turbidity levels and debris loading were observed after
rainfall events at both stream crossings compared with observations made during rainfall events between
2006 and 2008 (Jordan, Biological Assessment and Evaluation for the Conner Creek Fish Passage
Improvement Project). The higher debris loading may be attributed to downstream effects of the burned
area in the upper watershed.
Cumulative Watershed Effects
The Forest Service evaluates Cumulative Watershed Effects (CWE) at various levels of planning to
initiate mitigation measures to minimize risk of significant adverse impacts on beneficial uses of water
(R-5 FSH 2509.22, section 20.3). The Forest CWE analysis process evaluates potential impacts of land
management on mass wasting, surface runoff, erosion and stream channel response. Watershed condition
was documented in the Final Environmental Impact Statement (FEIS), Appendix H prepared for the
Forest Plan (USFS, 1994). That analysis established Threshold of Concern (TOC) values for specific
watersheds and documented watershed condition based on disturbance levels measured by the Equivalent
Road Acre (ERA) methodology (Haskins, 1983). The ERA methodology documents past actions and
converts disturbance levels to “roaded acres” for comparison and tracking. The amount of disturbed or
impervious ground provides an index of rainfall-runoff response to the proposed actions, as well as a
proxy for other indirect effects of disturbance (such as sediment mobilization and delivery). The ERA
method can be used to evaluate and compare proposed future actions by predicting the added level of
disturbance that would result from project implementation. Watershed condition based on comparison of
ERA to TOC is defined as follows: Class I - ERA less than 40 percent of TOC (watershed condition is at
or near potential); Class II - ERA between 40 and 80 percent of TOC (watershed condition is between
potential and threshold of concern); Class III - ERA greater than 80 percent of TOC (watershed condition
is close to, but below TOC). A recent CWE analysis for 7th-field HUC level watersheds across the Forest
was completed in November 2008 in order to include the impacts of the 2008 fires on watershed
condition (USFS, 2009b). The results of this analysis are summarized for Conner Creek in Table 2
below. The Conner Creek-Trinity River HUC7 is currently in Condition Class II. Condition Class II
watersheds have a moderate risk of adverse cumulative effects from project activities.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Table 2. Conner Creek 7th field sub watershed ERA values post 2008 fires.
Watershed
Acres
TOC
(%)
Fire
ERA
Harvest
ERA
Roads
ERA
Current
ERA3
%
ERA
8,362
16
426.6
44.9
164.4
635.9
7.6%
Current Risk
Ratio
(%ERA /
%TOC)
0.48
The Eagle Fire increased ERA levels in many 7th-field watersheds, including Conner Creek and as noted
above, monitoring has detected higher turbidity levels and debris loading at both stream crossings
following the fire. It is likely that some hydrologic recovery related to vegetative regrowth and
consequent reduction in runoff response has occurred since the post-fire analysis was completed, but
given the high burn severity experienced in the upper watershed and the delay in sediment and debris
routing time through the system to the drainage outlet, complete recovery is not anticipated on the order
of 101 years.
In respect to water resources, beneficial uses of water, watershed condition, and stream and riparian
habitat condition and quality, there is a need to restore stream connectivity and natural routing processes,
notably given the upper watershed conditions from the Eagle Fire. The County road crossings were not
adequately sized to convey large storm flows and associated bedload and debris prior to the Eagle Fire.
The post-fire predicted increases in flows, bedload routing and debris transport that are anticipated over
the next few decades will continue to affect hydrologic processes and fish habitat and threaten the
integrity of the County roads. This project would improve hydrologic connectivity at the crossings
without measurably increasing the ERA level.
Baseline Conditions for Conner Creek
Unless otherwise noted, all baseline information for Conner Creek is from the SCI conducted in July 2007
by the Forest (USDA-FS 2007a).
Temperature
Temperature measured at 58 degrees Fahrenheit at
1130 hrs on July 18, 2007. Temperatures of less
than 67 degrees F are desired for a properly
functioning stream.
Properly Functioning
Turbidity
Conner Creek becomes turbid almost immediately
after precipitation events due to a large landslide
located upstream of Red Hill Road. Prior to the
2008 fires, the stream would clear within several
hours and there were no other known turbidity
problems in Conner Creek. As evidenced during
higher flow events in 2009 through 2011, the
upslope fire effects are contributing to higher runoff
rates and increased turbidity levels.
At Risk
Chemical/Nutrient Conner Creek has low levels of contamination from
agriculture, industry and other sources; there were
Contamination
no excess nutrients detected.
Physical Barriers
3
Culverts on County Road No. 449 and No. 415
serve as partial barriers to migrating fish (FishXing
analysis of RED and GREY, 2000 Trinity County
Migration Barrier Inventory).
Properly Functioning
Not Properly
Functioning
This project will remove
those barriers and
Includes past and present actions on Federal, State, Private lands (data from Burnt Ranch-Solider Creek WA, 2009).
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
improve the baseline
condition to Properly
Functioning
Substrate
The mean percent pool tail fines is 1.6% which
indicates proper substrate function.
Properly Functioning
Large Woody
Debris
Conner Creek has 83 pieces LWD per mile with 16inch DBH, but only 3 exceed the 50-foot length.
LWD amounts are expected to increase over the
next decade due to the upslope fires.
Not Properly
Functioning
Pool Frequency
Conner Creek has 67 pools per mile. Frequency is
one pool every 79 feet (1 pool every 4.8 bankfull
widths - a properly functioning pool frequency
would have at least one pool every 3-7 bankfull
widths). There was only one pool with a 36 inch
depth, which indicates improper function of pool
maximum depth.
Not Properly
Functioning
Off-channel
Habitat
Conner Creek has minimal backwater habitat with
cover and low energy off-channel areas.
At Risk
Refugia
Conner Creek has minimal backwater habitat and
minimal LWD but a high frequency of shaded
pools. Shade measurements were taken at 50
locations within the survey segment and mean shade
was 80%. The culvert barriers limit the usefulness
of Conner Creek as refugia.
Not Properly
Functioning
Width/Depth
Ratio
Conner Creek is a Rosgen “B” type channel with a
mean W/D ratio of 21.8. Width/Depth ratios greater
than 12 are desired for properly functioning “B”
channels. Mean entrenchment ratio was 1.3. Mean
bank full and flood plain widths were 16.6 ft and
21.9 ft.
Properly Functioning
Streambank
Condition
Conner Creek has 13% bank stability, 69%
vulnerability and 18% instability.
Not Properly
Functioning
Floodplain
Connectivity
Conner Creek has minimal floodplain connectivity.
Not Properly
Functioning
Change in
Peak/Base Flows
Cumulative watershed effects (CWE) modeling
after the 2008 fires shows Conner Creek
subwatershed in WCC II with the primary
disturbance being the limited road network in the
subwatershed and the 2008 fires.
At Risk
Increase in
Drainage Network
Conner Creek has had a moderate increase in
drainage density due to the road network in the
northwestern section of the drainage and the high
density of road networks in the lower watershed.
At Risk
Road Density and
The Conner Creek subwatershed has 2.4 miles of
At Risk
10
Expected upward trend
as a result of the Eagle
Fire
Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Location
roads per square mile, with two County roads
located in the valley bottom and numerous short
distance private roads.
Disturbance
History
A CWE analysis was completed for the Down River
Community Protection Project analysis area across
numerous HUC5-HUC 8 watersheds in 2009 (takes
into account effects of 2008 fires). That analysis
showed that the Conner Creek subwatershed is at
47.5% of TOC, maintaining the WCC II level.
Properly Functioning
Riparian Reserves
The Riparian Reserves of Conner Creek are
characterized by wild grape, vine maple and
elderberry along both banks. Abundant shadetolerant vegetation including Pacific yew, Mountain
dogwood and sword fern under an old growth
overstory of Douglas-fir, Sugar pine and Ponderosa
pine provide substantial canopy cover and
opportunities for LWD recruitment.
Properly Functioning
Project Area Scale
Watershed scale assessments have been completed as discussed above and flows and debris movement
within the project area have been monitored by 5C Program staff since 2001 (refer to Figure 3). Boberg
and Kenyon (CDFG, 1979), Ross Taylor and Associates (2001 and 2006) and TRMU fisheries biologist
Loren Everest (2006) have also conducted assessments.
SHN Consulting (2006) and DOT (2010) design engineers conducted the hydraulic analysis and Taber
(engineering geologists) completed a foundation and geotechnical analysis at Conner Creek Road (Taber,
2011). Thalweg profiles and cross section measurements were taken above, below and within the stream
crossings. A reference reach was established approximately 300 feet upstream of Crossing #2, indicating
an annual flow channel width of 14 feet with a 2-year recurrence width of 16 feet. The reference
upstream of Crossing #1 has an annual flow channel width of 11 feet and a 2-year recurrence width of 14
feet. The average channel gradient through both reaches is 5%. The gradient between the tailwater
control elevation and the top of the crossings averages 5% for both crossings as shown in Figure 7.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Figure 7. Existing channel profiles at both sites
Recurrence intervals for the 5-, 10-, 25-, 50- and 100-year storm were calculated from Regional FloodFrequency Equations for the North Coast Region of California with site-specific characteristics of annual
precipitation, elevation index, and drainage area (DOT 2011). The recurrence intervals as derived from
the North Coast Regional Flood-Frequency Equations are summarized in Table 3 below.
Table 3. Storm Flow Recurrence Intervals
Conner Creek Project
5-Year
Flow (cfs)
10-Year
Flow (cfs)
25-Year
Flow (cfs)
50-Year
Flow (cfs)
100-Year
Flow (cfs)
Conner Creek Road: Crossing #1
353.4
504.6
709.7
947.5
1,806
Red Hill Road: Crossing Site #2
351.3
501.7
705.7
942.1
1,770
Both crossings exhibit past evidence of overtopping and diverting and the Eagle Fire has increased the potential
for runoff, debris and bedload transport at the already restricted crossings. Crossing #1 is undersized for the
100-year storm flow and is estimated to overtop on an 18-year storm flow. This crossing is a complete barrier
to all salmonid fish species and life stages during all migration flows, primarily due to the perched outlet and
leap. The offset baffles within the box culvert are ineffective at improving passage and slowing flows as they
clog with woody debris (Figure 3). Crossing #2 is also undersized for the 100-year flows and is estimated to
overtop on a 43-year recurrence storm flow. This crossing is a partial barrier to salmonids and resident trout,
violating CDFG passage criteria on 55% of migration flows. It is a complete barrier to all juvenile age classes
and species, primarily due to the outlet leap and flow velocities within the culvert. The steel ramp baffles most
likely improve adult passage, but are ineffective at reducing velocities during migration flows to levels that
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
provide for effective juvenile passage. Upgrading Crossing #2 necessitates upgrading Crossing #1 to allow
passage of higher levels of large woody debris anticipated over the next decade.
Table 4. Comparison of existing and desired condition associated with the
Conner Creek Fish Passage Improvement Project
 Stream crossing culverts present either a partial or total upstream
Existing Condition
Desired Condition
migration barrier for adult and juvenile anadromous salmonids.
 Stream crossing culverts are undersized for the 100-year return interval
storm flows and exhibit past evidence of overtopping and diversion.
 Stream crossing culverts replaced and/or modified to allow for passage
of adult and juvenile steelhead and coho salmon during the full range
of migration flows.
 Stream crossing culverts replaced and/or modified to convey 100-year
flows for the watershed (estimated at 1,155 cfs).
At both crossings there is minimal evidence of active erosion either on stream banks or within the active
channel areas; there is well developed tree and shrub canopies upstream and downstream of the crossings.
A pebble count completed during the 2007 SCI (Figure 8) showed limited quantities of clay to sand-sized
particles in the bed matrix. Rather, the channel consists of predominantly larger particles consistent with
a high gradient, high energy channel. Approximately 1% of the stream bed consists of fine gravel (~6
mm) with the median particle size being coarse gravel (~48mm). Approximately 12% of the channel
material consists of large boulders and bedrock. The geotechnical foundation report (Taber, 2011)
indicates similar conditions exist to a depth of 7.5 feet and deeper:
“The upper unit consists of silty gravels and generally had a loose to compact consistency (per
Standard Penetration blow counts) and extends below the pavement and aggregate sections to
elev. 92.3± (7.5±ft depth). The lower unit consists of silty gravels with cobbles and local
boulders. The unit generally had a compact to very dense consistency (per Standard Penetration
blow counts) and extends from below the upper unit of alluvium (elev. 92.3±) to the top of the
rock unit. Boulder size material, up to 2±ft in diameter, was encountered in boring B-1; and up to
1±ft in diameter in boring B-2…Larger boulders up to 4 to 5-ft in diameter were also observed at
ground surface and in the slopes surrounding the proposed bridge location.”
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Figure 8. USFS Pebble Count- Conner Creek
Comparative Watershed Assessment
A similar project was completed in Soldier Creek, an adjacent watershed, in 2005 that provides
comparative analysis of hydrologic impacts to Conner Creek. In 2005, the DOT and 5C replaced two
crossings within the lower reach of Soldier Creek on Evans Bar and Dutch Creek Roads. In 2009, the
Forest Service replaced a culvert barrier on Soldier Creek (upstream).
The two crossings on Soldier Creek that were replaced by DOT in 2005 are approximately the same
distance apart as Crossing #1 and #2 on Conner Creek. The watershed characteristics for both are also
relatively similar as shown in Table 5 below. The pre-project conditions at both Soldier Creek crossings
were undersized and overtopped on a 7-year recurrence interval (Dutch Creek Road) and a 6-year
recurrence interval (Evans Bar Road). Crossing #2 overtops on a 43-year interval and Crossing #1
overtops on an 18-year interval but the crossings backwater on the approximately 15-year flow.
Table 5. Comparative Watershed Data
Existing Conditions
Conner Creek
Soldier Creek
Watershed Area
3,243 acres
4,580 acres
Watershed Area Ratio
1.41:1
0.71:1
High Point Elevation
5,707’
5,556’
Low Point Elevation
1,440’
1,500’
Elevation Difference
4,267’
4,113’
Main Stem Channel Perennial
Length
Geology
4.8 Miles
5.0 Miles
North Fork Terrane
W/Diabase
1,160 cfs
1.55:1
37”
North Fork Terrane
Q100
Q100 Ratio
Mean Annual Precipitation
1,800 cfs
0.65:1
40”
Given that the watersheds are at similar elevations, have comparable annual precipitation and principally
vary only by watershed area, the Q100 flows in the Conner Creek and Solider Creek subwatersheds are
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
very similar. Both originate on the Hayfork Divide. The Soldier Creek watershed is located five miles
southeast of Conner Creek and is geologically similar, though there is a large diabase intrusion transecting
the central portion of the Conner Creek watershed. Conner Creek has a somewhat steeper gradient but
bedload strata sizes are similar. The two County Soldier Creek crossings have been monitored for
evidence of cutbank and slope erosion since their installation in 2005 with no significant rill or gully
erosion observed at either crossing. In December 2005/January 2006 there was a large enough storm to
declare state and federal disasters for road damage throughout Northern California. Neither of the Soldier
Creek crossings showed any adverse response to the 2006 high flows. Post-project channel changes at
Soldier Creek have been minimal and are being studied as part of a nation-wide Forest Service assessment
of channel function following restoration activities. The study, being conducted by Dr. Margaret Lang of
Humboldt State University, will provide information on geomorphic channel response at crossings where
undersized culverts have been remediated with active channel design structures. Based on the
comparative watershed analysis with Soldier Creek, the design for the Conner Creek crossings should not
result in significantly different bedload responses.
III. Erosion/Water Quality Risk and Effects Analysis
Implementation of the project would meet long-term benefits for salmonid restoration outlined by the
regulatory agencies, NWFP and Aquatic Conservation Strategy Objectives and the Forest Plan goals and
objectives as described in Section IV below. In determining the appropriate level of NEPA review, the
thresholds of significance for the use of NEPA Categorical Exclusions have been established for
hydrologic impacts as follows:
1. Floodplains: Executive Order 11988 provides direction to avoid adverse impacts associated with the
occupancy and modification of floodplains. Floodplains are defined by this order as “…the lowland
and relatively flat areas adjoining inland and coastal waters including flood-prone areas of offshore
islands, including at a minimum that area subject to a 1% (100-year recurrence) or greater chance of
flooding in any one year.”
Relative to floodplain impacts, the project would result in meeting the goal of restoring floodplain
function at both crossings by replacing the existing culverts with structures sized to convey the 100year flow. The existing crossings convey flows and associated bedload and debris during smaller
storm events before upstream backwatering begins. Flows in exceedance of the 15-year flow
backwater the crossing inlets, resulting in debris plugging and deposition of larger sized particles that
artificially alter the upstream floodplain. The crossings overtop at the 18-year (#1) and 43-year (#2)
recurrence interval and the significant difference between flows is primarily due to the larger roadfill
prism at Crossing #2. The road prism (~dam) allows for a significant reservoir to form upstream
compared to the minimal fill and reservoir capability at Crossing #1.
The project is consistent with the direction set forth in Executive Order 11988. No extraordinary
circumstances with respect to floodplains would be created by the project. There are no short-term
adverse effects to floodplains related to construction. Work within the floodplain will be done in
accordance with BMPs. In the long term, considerable floodplain functionality would be restored.
2. Wetlands: Executive Order 11990 was promulgated to avoid adverse impacts associated with
destruction or modification of wetlands. Wetlands are defined by this order as “…areas inundated by
surface or ground water with a frequency sufficient to support, and under normal circumstances does
or would support, a prevalence of vegetative or aquatic life that requires saturated or seasonally
saturated soil conditions for growth and reproduction. Wetlands generally include swamps, marshes,
bogs and similar areas such as sloughs, potholes, wet meadows, river overflows, mud flats and natural
ponds.”
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
The project would not alter or affect wetland habitats as there are no wetland habitats within the
project area. Therefore, no extraordinary circumstances with respect to wetlands would be
created by the project.
3. Municipal watersheds: Municipal watersheds are defined in FSM 2542.05 as “A watershed that
serves a public water system as defined in the Safe Drinking Water Act of 1974, as amended (42
U.S.C. §§ 300f, et seq.); or as defined in state safe drinking water statutes or regulations.”
There are no municipal water systems downstream of the project as defined in FSM 2542.05.
Therefore, no extraordinary circumstances with respect to municipal watersheds would be
created by the project.
While the project would have long-term benefits, an assessment of potential effects of the short-term
impacts must be considered and evaluated to determine the appropriate level of environmental evaluation
and to develop resource protection measures that reduce the potential impact(s). If the hydrologic
analysis for a project determines that there are: a) no, or minimal, short-term adverse impacts of a project
to hydrologic resources and water quality; b) that the project would not result in extraordinary
circumstances to the defined resource values [FSH 1909.15 Chapter 30.4; 36 CFR 220.6(b)]; and c) that
the project would result in long-term benefits to hydrologic resources, then the project would not have
extraordinary impacts to floodplains, wetlands or municipal water sources, as described above.
Project Related Erosion Risks
The current condition assessment (USFS, 2008) shows an increasing trend for potential culvert plugging
and overtopping of the roads at both crossings. The increasing trend is directly related to the short to midterm increases in peak discharge and bedload and debris movement within the upper 41% of the
watershed; due to low to moderate burn intensities during the 2008 Eagle Fire where high intensity, standreplacing fires occurred along some of the ridges in the watershed (USFS, 2008). Prior to the Eagle Fire,
both crossings had moderate to moderately high plug potential due to being undersized for high flows and
the offset and steel ramp baffles (Taylor, 2002).
Crossing #2 has the greatest potential for significant sediment delivery from either a roadfill failure or
project construction activities. A roadfill failure that could result from culvert plugging, headwall and
road overtopping from high flows and associated debris has the potential to deliver between 750-2000
cubic yards of sediment to the downstream reached. Subsequent sediment delivery from failure-related
scour, channel downcutting and/or bank erosion are not factored into this estimate. During construction
at Crossing #2, an estimated 740yd3 of fill material would be excavated and endhauled to an existing
open, flat storage area near the intersection of Conner Creek and Red Hill Roads. There is potential for
some material to drift down slope and be deposited in the stream channel during excavation. There is also
potential for the newly placed fill slopes to erode and deposit sediment due to rainfall impacts, slumps or
rill and gully erosion. All three types of potential sediment delivery (drift, slump or rill) are typical risks
associated with roadfill slopes and stream crossing replacement/modification activities. Development and
adherence to effective resource protection measures and design criteria are key in reducing if not
preventing potential sediment delivery. Refer to Section V for a discussion of the measures taken to
prevent these types of impacts. Crossing #1 has a significantly lower potential for pre-, during- and postconstruction related sediment delivery. The existing concrete box culvert will remain in place during
excavation of the new footing and abutment structures, protecting the stream channel from excavationrelated sediment. Minimal upstream channel excavation is required to restore the natural channel
gradient. At both crossings, engineered stream channel material would be installed and jetted (to seal
voids) within the new crossing reach(es) and outlet pool(s). At both crossings, the channel would be dewatered during this process, a recycled water system would be used during jetting and any excess water
would be pumped out of the floodplain and discharged in a location where it would not affect water
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
quality. Removal of the corrugated metal pipe and concrete box culvert at both crossings (and all
construction work associated with the project) would be done in accordance with the 5C Program’s “A
Water Quality and Stream Habitat Protection Manual for County Road Maintenance in Northwestern
California Watersheds” (or Roads Manual) BMPs. Both stream channels will be dewatered at the time of
removal. Refer to Section V for a discussion of Roads Manual BMPs and Resource Protection Measures
that will minimize the risk of significant surface erosion and reduce if not prevent sediment delivery to
the stream channel.
Project Related Water Quality Risks
The North Coast Regional Water Quality Control Board (NCRWQCB) implements both the federal Clean
Water Act and state Porter-Cologne Water Quality Control Act for waters within their area of jurisdiction
(see Section IV- Regulatory Environment). The 2007 Water Quality Control Plan (Basin Plan) for the
North Coast Region identifies beneficial uses and sets water quality objectives for waters within the
Trinity River Hydrologic Unit. The NCRWQCB adopted water quality objectives in the Basin Plan for
the reasonable protection of beneficial uses and prevention of nuisance from activities on National Forest
System lands. These objectives are consistent with the state and federal anti-degradation policy and
include suspended material; settleable material; oil and grease; sediment; turbidity; pH; temperature;
toxicity; and chemical constituents. Trinity County DOT fulfills these obligations through proper
installation, operation and maintenance of state or federally certified Best Management Practices
described in the Roads Manual. The Forest Service meets its obligation through the 2000 Forest Service
Region 5 BMP handbook (USDA Forest Service, 2000). As noted in Section V, the project would be
conducted in compliance with the Roads Manual which includes project type-specific BMPs to maintain
water quality during and after construction that are similar to BMPs in the Forest Service BMP handbook.
In addition to the Basin Plan objectives, the US EPA prepared an Allocation Plan for sediment in the
mainstem Trinity River in 2000 (EPA, 2001) that included target indicators of watershed recovery as
shown below in Table 3-3 of the TMDL. Removal of undersized stream crossings is one of the targets
identified to restore cold-water fisheries beneficial use of the Trinity River (see Table 3-3 from the TMDL
on the following page).
The existing crossings are undersized for conveyance of storm flows, bedload and/or debris during large
storm events and prevent upstream migration of fish. The 2008 Eagle Fire has increased the risk of
crossing failure, primarily due to the expected higher peak storm discharges anticipated during the
watershed recovery period. Following the Eagle Fire, the Equivalent Road Acres (ERA) analysis of fire
impacts on watershed condition changed Conner Creek’s Condition Class from I to Condition Class II.
Condition Class II watersheds have a moderate risk of adverse cumulative effects from project activities.
The HRA (Hydrological Resource Assessment) modeling predicted a peak increase in 10-year recurrent
storms runoff rates of 1.5-1.8 times compared to pre-fire conditions in the Conner Creek watershed
(USFS, 2008). Portions of the soils severely burned in the fire have developed hydrophobic conditions
that result in increased runoff rates. Tree root degradation and decay from stand mortality will continue
to occur over the next 20 to 30 years; and new tree and shrub root growth will not fully replace the soil
stabilization factors of lost roots during this time. Roots are an important contributor to providing soil
support and transpiring water from the soil column and the greatest impact of lost tree root strength to soil
stability occurs approximately 10 years after tree mortality (Zeimer, 1981).
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Threats to habitat quality and species abundance and diversity may be exacerbated where human-caused
disturbance has previously fragmented and compromised aquatic habitat (Dunham et al, 2007, Gresswell
1999). Undersized drainage system failure, erosion and mass wasting failure of roadfill and stream
crossings can occur following fires (Coe, 2006). Biologically, the existing crossing structures prevent
upstream migration of anadromous salmonids and other aquatic vertebrates/invertebrates (refer to the
Conner Creek Fish Passage Improvement Project Fisheries Biological Assessment and Evaluation).
Empirical evidence from completed 5C projects shows terrestrial wildlife mortality (deer, bear, raccoon)
on roads near barrier removal projects has significantly declined, notably where undersized perched
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
culverts have been replaced with bridges or embedded culvert structures. The 10-foot diameter culvert at
Crossing #2 acts as a choke point for large debris that cannot be transported downstream and the box
culvert at Crossing #1 has been documented to trap debris within the offset baffles. The new crossings
will convey the 100-year recurrence interval flow and provide for transport of bedload and debris more
efficiently; which is critical due to the upslope loss of vegetation and wood structures as a result of the
Eagle Fire. Empirical observations of a similar sized watershed (West Weaver Creek) following the 2001
Oregon Fire noted extensive sediment and wood movement into and through a similar arched crossing on
Oregon Street in the Weaverville area within the first decade following the fire (Figure 9).
The Forest Plan establishes Forest Goals to “provide for the protection, maintenance, and improvement of
wild trout and salmon habitat,” to “maintain or improve water quality and quantity to meet fish habitat
requirements and domestic use needs (Forest Plan, page 4-4),” and to “maintain water quality to meet or
exceed applicable standards and regulations (Forest Plan, page 4-6).” These Goals, combined with the 5C
and Trinity County fisheries and water quality enhancement programs over the past decade, meet other
state and federal objectives including the Clean Water Act Trinity River TMDL Allocation Plan,
California Coho Recovery Strategy, and the Klamath Mountain Steelhead recovery direction cited by the
National Marine Fisheries Service (NMFS) in the Federal Register (April 4, 2001 Volume 66).
Figure 9. LWD transport through West Weaver Creek crossing following a
high intensity fire in the upper watershed.
In addition, the Standards and Guidelines issued with the Record of Decision for the 1994 NWFP
incorporate the Aquatic Conservation Strategy (ACS) Objectives that apply to Riparian Reserves and Key
Watersheds (Appendix B).
The ACS emphasizes maintenance and restoration of the physical and biological integrity of aquatic and
riparian habitat. Anthropogenic barriers to fish passage and bedload and debris transport combined with
landscape-scale wildfire influences degrade aquatic ecosystems beyond the range of natural variability,
and hence are at odds with the ACS. The purpose and need for the project meets with the Forest Plan’s
water quality and beneficial uses goals, such as providing for the protection and improvement of wild
trout and salmon habitat, improving water quality to meet fish habitat requirements and maintaining water
quality to meet or exceed applicable standards and regulations. Replacing and modifying the crossings
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
will not only improve the fish passage conditions but will also improve flow capacities, thereby reducing
the maintenance requirements and emergency response expenditures for Trinity County DOT. The
project would not change the current watershed condition class or ERA levels and will improve hydraulic
function at both crossings, allowing for improved passage of salmonids at higher flows. Trees proposed
for removal from the roadfill at Crossing #2 would not have provided LWD to the downstream channel
because they are on the upstream side of the culvert and would not pass through the pipe. Large LWD
that is mobilized from upstream would also not pass through the existing culvert, and would likely have
to removed from upstream to prevent jams, plugging and potential crossing failure, with no habitat
benefits. After completion of the project, there will be an improved opportunity for conveying LWD
through the new crossing with subsequent benefits to salmonid habitat lower in the system. Since the
trees can be removed from the roadfill with intact root wads, there is an opportunity to utilize the material
in channel habitat improvement projects in the future.
Removal of vegetation on the existing roadfill at Crossing #2 would not measurably impact water
temperature. The channel flows from west to east with two forested, parallel ridges that provide 50 to
70% canopy to the stream. None of the trees proposed for removal currently provide significant shade
that is not already provided by the overhead and adjacent road fill.
The net change in leaf litter from removing the trees is negligible. There would be an insignificant loss of
litter fall to the stream from removal of the trees. The majority of trees proposed for removal are too
small (<1 to 6”) to offer significant amounts of leaf biomass and much of the existing fallen leaf litter
lands on the road fill rather in the creek. The project includes replanting of native trees on the replaced
fill, including trees in the 1 to 2-inch diameter class to promote rapid revegetation.
The mainstem Trinity River (4th-field HUC) is located approximately 1 mile east of the project area and
contains Chinook and coho salmon and steelhead trout. There would be no direct effects to anadromous
fish at the 4th- or 5th-field watershed scale. Indirect effects include short-term increases in substrate
mobility and turbidity from coarse and fine sediment transport and these impacts would be immeasurable
at the 4th- and 5th-field scale. Effects at the 7th-field watershed and project site scale are described above.
IV. Regulatory Environment
The following provisions of law, regulation and policy provide direction for the conclusions in this report
regarding implementation of the Conner Creek Fish Passage Improvement Project from the perspective of
watershed function and protection.
Federal Endangered Species Act (1972): The coho salmon within the Southern Oregon Northern
California Coast evolutionarily significant unit (SONCC ESU) was listed as a Threatened species under
the Endangered Species Act in 1997. The project would improve habitat access for federally threatened
coho salmon4 and the Klamath Mountains Province Distinct Population Segment of steelhead (KMP
DPS),5 a Forest Service sensitive species. The proposed action affirms the Klamath Mountain Steelhead
recovery direction cited by the National Marine Fisheries Service (NMFS) in the Federal Register: April
4, 2001 Volume 66:
“NMFS intends to capitalize on the significant efforts being made by all entities, from large-scale
transboundary actions adopted via the Northwest Forest Plan and Klamath and Trinity Rivers
Restoration Acts to more localized efforts like those implemented by the Five Counties Salmon
4
NOAA Fisheries Coho Recovery Planning: www.swr.noaa.gov/recovery/Coho_SONCCC.htm
NOAA Fisheries Steelhead Information: www.nwr.noaa.gov/ESA-Salmon-Listings/SalmonPopulations/Steelhead/STKMP.cfm
5
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Conservation Program and Scott River Watershed Council. These efforts, coupled with ESA protective
regulations for listed coho salmon, will likely improve conditions for KMP steelhead as well.”
Magnuson-Stevens Reauthorization Act Klamath River Coho Salmon Recovery Plan (2007): This
plan analyzes and makes recommendations regarding the recovery of the threatened Southern
Oregon/Northern California Coast (SONCC) coho salmon evolutionarily significant unit (ESU) and
hydrologic units (HUs); areas (HAs); and sub-areas (HSAs) within the range of the SONCC ESU. It
incorporates recommendations from the Recovery Strategy for California Coho Salmon prepared by the
California Department of Fish and Game in 2004.
Executive Order 11998 (1977); Floodplain Management: This Executive Order requires all Federal
agencies to take actions to reduce the risk of flood loss, restore and preserve the natural and beneficial
values in floodplains, and minimize the impacts of floods on human safety, health and welfare.
Federal Clean Water Act: Key sections of this law and related amendments include: Section 208
requiring states to develop and use Best Management Practices (BMPs) for managing non-point source
pollution; Section 303(d) requiring that waterbodies that are repeatedly out of compliance with the
applicable water quality standards be subject to a Total Maximum Daily Load or TMDL; and Section 404
regulates discharge of dredged or fill material into navigable waters (waters of the U.S). The project is
included under the Army Corps of Engineers (ACOE) Regional General Permit (RGP) No. 12 for those
projects funded under the California Department of Fish and Game’s (CDFG) Fisheries Restoration Grant
Program (FRGP). Under Section 401 of the Clean Water Act (33 U.S.C. Section 1341), an applicant for a
Corps permit must first obtain a State water quality certification before a Corps permit may be issued.
Water quality certification is issued on an annual basis. CDFG has established an annual certification and
project reporting procedure with the State Water Resources Control Board. Projects scheduled for the
upcoming year are submitted, in addition to annual reports listing the previous year’s projects. The 2011
Section 401 Water Quality Certification will be applied according to the established procedure. No Corps
permit will be granted until the applicant obtains the required water quality certification. The Corps may
assume a waiver of water quality certification if the State fails or refuses to act on a valid request for
certification within 60 days after the receipt of a valid request, unless the ACOE District Engineer
determines a shorter or longer period is reasonable for the State to act. An evaluation of the proposed
activities under the current RGP 12, and their impact, includes application of the guidelines promulgated
by the Administrator of the Environmental Protection Agency under Section 404(b)(1) of the Clean Water
Act (33 U.S.C. Section 1344(b)). As such, the project will not be enrolled under the Forest Service
waiver of discharge requirements. The proposed project is located on a County road where the County
has an approved easement with the United States Department of Agriculture for maintaining the road and
associated right of way areas and the primary function of the Forest Service in this project is as a
contributing partner for project funding, requiring full compliance with the NEPA. The Forest Service
waiver is limited to timber sale activities and does not apply to the proposed action. The project will
comply with Section 401 requirements that are provided under the RGP No. 12 and the CDFG water
quality certification. The time limit for completing the work under the RGP No. 12 is December 1, 2015.
Clean Water Act (CWA), Porter-Cologne, Basin Plan
Per the CWA, Porter-Cologne and the Management Agency Agreement (MMA) with the State Water
Resources Control Board, the Forest Service accepts responsibility as the water quality management
agency for National Forest lands in California. Those responsibilities include providing for review of
project planning by the State, and implementation of the mutually agreed-on Best Management Practices
developed by the Forest Service to meet the regulatory requirements of the CWA, the EPA and the MAA
(USDA Forest Service, 2000). The MAA gives the State broad authority to administer the CWA and
Porter-Cologne, and to regulate ground-disturbing activities that have the potential to affect water quality
and beneficial uses of water. The State may issue notices of violation, cease and desist orders, cleanup
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
and abatement orders and impose fines and monitoring requirements when water quality is threatened or
degraded by activities of the Forest Service or under Forest Service jurisdiction.
Because Conner Creek is 303(d) listed as an impaired water body for sediment and temperature, any
project disturbance that may deliver sediment or elevate stream temperatures is subject to regulatory
scrutiny and BMP application sufficient to prevent sediment delivery or increased temperatures from
affecting beneficial uses of water is required. BMPs have therefore been selected to reduce or eliminate
the threat of water quality impairment from the proposed action.
Trinity River Sediment Total Maximum Daily Load Allocation Plan: The Trinity River was
designated as sediment impaired under Section 303(d) of the Clean Water Act and in 2000 the TMDL
was completed (EPA, 2000). The project will implement the following Instream and Watershed
Indicators listed in Table 3.3 Sediment Indicators and Targets of the Trinity River Sediment Total
Maximum Daily Load:
 Increase Large Wood Debris Target: The project will meet this target by allowing transport
of LWD that cannot currently be routed through one or both of the existing crossings. The
new crossings will convey the 100-year recurrence interval flow and provide improved
transport for LWD as described above.
 Reduce Diversion Potential & Stream Crossing Failure Potential: The project will allow
conveyance of the 100-year recurrence interval flow and address short-term and mid-term
increased peak discharge potential resulting from the Eagle Fire. Larger culverts/crossings
will also reduce the potential for culvert plugging at the inlet with LWD and subsequent
ponding of water, diversion and culver failure.
 Restore Hydrologic Connectivity: The existing culverts do not allow for natural routing of
bedload and debris. The existing culverts backwater at less than the 18- and 43-year flood
flows and the stream begins dropping bedload under those conditions. The project will allow
for natural routing of flows and bedload transport during these higher flows.
 Northwest Forest Plan Aquatic Conservation Strategy (ACS): For details on how the
project will implement Riparian Reserves, the Aquatic Conservation Strategy Objectives and
Riparian Management (Prescription 9) objectives, refer to the Fisheries Biological
Assessment and Biological Evaluation and Appendix B of this document.
National Environmental Policy Act (1969) and CEQ’s Implementing Regulations (40 CFR 1500):
The National Environmental Policy Act (NEPA) is the basic national charter for protection of the
environment. The Council on Environmental Quality (CEQ) was established by the NEPA (Act) to
interpret and implement the provisions of the Act as they apply to Federal agencies. The Act requires
federal agencies to perform environmental analysis of proposed activities, in order to assess the nature,
characteristics and significance of the effects of a proposed action and its alternatives on the human
environment.
 Forest Service Manual 1950: The Forest Service Manual, Chapter 1950 (FSM 1950) –
Environmental Policies and Procedures sets forth Forest Service management objectives, policy
and responsibilities for meeting the requirements of NEPA.
 Forest Service Handbook 1909.15: The Forest Service Environmental Policies and Procedures
Handbook (FSH 1909.15) provides procedural direction for implementing NEPA, the CEQ
regulations, and USDA NEPA policies and procedures. Chapter 30 contains the documentation
and process requirements for categorical exclusions, which the Conner Creek Fish Passage
Improvement Project is promulgated under. Section 30.3 directs that “a proposed action may be
categorically excluded from further analysis and documentation in an EIS or EA only if there are
no extraordinary circumstances related to the proposed action.” This section also describes
“resource conditions that should be considered in determining whether extraordinary
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011

circumstances related to a proposed action warrant further analysis and documentation in an EA
or an EIS…”, including “flood plains, wetlands, or municipal watersheds.”
Water Quality Control Plan for the North Coast Region (Basin Plan) (2007): The Basin Plan
is the guiding document regulating water quality within the North Coast Region. It is designed to
preserve and enhance water quality and to protect beneficial uses of water. Each regional water
board, in this case the North Coast Regional Water Quality Control Board (NCRWQCB),
identifies “impaired waterbodies” [the 303(d) list] that do not meet the standards set forth in the
Basin Plan and may not fully support beneficial uses of water. Each water board then develops
pollution reduction plans establishing Total Maximum Daily Loads (TMDLs) to improve and
restore water quality to meet Basin Plan standards. TMDLs established by the EPA are in place
for reduction of sediment loads in the Trinity River & Conner Creek watersheds (EPA 1998).
Implementation and monitoring plans are to be developed by the NCRWQCB.
NEPA, FSH 1909.15, Executive Order 11998
The project is categorically excluded from further NEPA analysis under Category 7 [36 CFR 220.6(e)(7)]
as the project description and design meets the terms of this category. Per the conditions of categorical
exclusion, it must be demonstrated that there are no extraordinary circumstances that affect a number of
resource conditions, including flood plains, wetlands, or municipal watersheds and “the mere presence of
one or more of these resource conditions does not preclude use of a categorical exclusion (CE). It is the
existence of a cause-effect relationship between a proposed action and the potential effect on these
resource conditions and if such a relationship exists, the degree of the potential effect of a proposed
action on these resource conditions that determine whether extraordinary circumstances exist.” [FSH
1909.15_30.4; 36 CFR 220.6(b)]. As described above, the Conner Creek Fish Passage Improvement
Project will restore a portion of the 100-year floodplain and project design standards and BMPs would
reduce or eliminate the risk of negative effects to aquatic and riparian resources and water quality. Based
on the evidence of minimal effects from past similar stream crossing replacement activities and the
protection from resource damage that would be provided by project design standards, resource protection
measures and BMPs, no extraordinary circumstances with respect to floodplains, wetlands, or
municipal watersheds are present that would prevent the project from categorical exclusion from
further NEPA documentation.
Northwest Forest Plan Standards and Guides, Shasta-Trinity Forest Plan (Riparian Reserves,
Watershed Analysis, ACS Objectives)
The NWFP and the Forest Plan affect the proposed Conner Creek Fish Passage Improvement Project
through the established standards and guides and management direction. The land allocations established
by the NWFP ROD define Riparian Reserves with specified interim widths adjacent to waterbodies. For
perennial fish-bearing streams, the Riparian Reserve width consists of the stream and the area on each
side of the stream extending from the edges of the active stream channel to the top of the inner gorge, or
to the outer edges of the 100-year floodplain, or to the outer edges of riparian vegetation, or to a distance
equal to the height of two site-potential trees, or 300 feet slope distance (600 feet total, including both
sides of the stream channel), whichever is greatest.
Riparian Reserve widths may be adjusted during watershed analysis, although the intent was to adjust
widths for intermittent and ephemeral streams, with perennial Riparian Reserve widths in most cases to
remain constant. The entire Conner Creek Fish Passage Improvement Project area falls within Riparian
Reserves with exception of the one-acre flat staging area near the intersection of Conner Creek and Red
hill Roads. Consequently, ACS Objectives must be met for the proposed project activities to proceed.
ACS Objectives direct the Forest to maintain and restore a variety of watershed, stream and riparian
features, processes and functions and the standards and guides for Riparian Reserves state that “As a
general rule, standards and guidelines for Riparian Reserves prohibit or regulate activities in Riparian
Reserves that retard or prevent attainment of the Aquatic Conservation Strategy Objectives.”
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Work within the Riparian Reserves is allowed and resource protection measures and design criteria that
meet with the ACS Objectives would be utilized. These measures include directional felling of trees
when completing vegetation removal, utilizing oil absorbing booms, onsite spill prevention equipment,
utilizing silt fencing and straw bales/waddles for erosion control, installing temporary stream diversions
through the construction reaches at both crossings and native species revegetation plans as described in
Section V below. These resource protection measures would result in minimal disturbance to riparian
vegetation and would not result in bank destabilization or increasing the erosion hazard in the project or
action area Riparian Reserves.
Shasta-Trinity National Forest Plan – Forest-wide Goals and Standards & Guidelines: The project
meets the following Forest Plan goals:
 Provide for the protection, maintenance and improvement of wild trout and salmon habitat
(page 4-4);
 Maintain or improve water quality and quantity to meet fish habitat requirements and
domestic use needs (page 4-6);
 Maintain water quality to meet or exceed applicable standards and regulations (page 4-6).
The project will adhere to the following Forest Plan Standards & Guidelines:
 Coordinate road improvement and maintenance projects with other Forests, State and local
agencies, and cooperators, as needed (page 4-17).
 Coordinate rehabilitation and enhancement projects with cooperating agencies involved in the
Model Steelhead Stream Demonstration Project Plan and the Trinity River Basin Fish and
Wildlife Management Program (page 4-18).
 Implement Best Management Practices (BMPs) for protection or improvement of water
quality, as described in “Water Quality Management for National Forest System Lands in
California” (2000) for applicable management activities. Determine specific practices or
techniques during project level planning using information obtained from on-site soil, water
and geology investigations (page 4-25).
 Maintain and/or enhance habitat for threatened, endangered and sensitive species consistent
with individual species recovery plans (page 4-30).
Complete management direction, management prescriptions and standards and guidelines for the project’s
management area and land allocations can be found in the appropriate sections of the Forest Plan (Forestwide, page 4-23; Riparian Reserves, page 4-53; AMA, page 4-69; Trinity River Management Area, page
4-141, USDA-FS 1995.
V. Resource Protection Measures and Design Criteria
The project includes specific resource design criteria, protection measures and best management practices
(BMPs) to minimize effects to hydrologic function, fish, aquatic and terrestrial wildlife, plants, water
quality and soils. Activities that could result in potential negative impacts include aquatic species
relocation, construction within the stream channel (introduction of pollutants/sediment and species
impacts), minor vegetation removal, introduction of minor amounts of fine sediment, short-term duration
noise above ambient levels and potential introduction and/or spread of noxious weed species. The BMPs
for replacing a stream crossing, sediment prevention, aquatic species relocation, erosion control and
revegetation listed in the Roads Manual would be adhered to throughout project planning and
implementation. A full copy of the Manual, or specific chapters/appendices is available at:
www.5counties.org/Projects/FinalGeneralProjectPages/RoadsManual800.htm.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Minor amounts of vegetation would be removed in order to excavate the existing culverts at both
crossings, but revegetation efforts would mitigate the removal. Excavation of the roadfill at Crossing #2
is the highest level of disturbance associated with the project and upstream/downstream impacts to natural
channel banks would be limited. It is estimated that no more than 10 feet of the upstream/downstream
stream banks at both crossings would be disturbed, including tree/shrub removal. It is anticipated that
only trees within the road fill prism and immediately adjacent to the existing culvert would be removed at
this site. It is further anticipated that minimal impact to riparian trees would occur at Crossing #1. At
most, three alders located downstream of the crossing may have to be trimmed or removed if retention
does not allow for vehicle safety. Where trees need to be felled along the stream banks, directional felling
would be used to minimize disturbance to the stream banks.
“A Water Quality and Stream Habitat Protection Manual for County Road Maintenance in
Northwestern California Watersheds” (Roads Manual): The Trinity County Board of Supervisors
adopted the Roads Manual in 2004 that lists Best Management Practices (BMP) for County road
maintenance. In 2007 the National Marine Fisheries Service incorporated the Roads Manual into Limit
10, Section 4(d) of the Federal Endangered Species Act for incidental take of coho salmon.
Appendix B of the Roads Manual lists all BMPs and select BMPs are included in Appendix A of this
document. The BMPs are prescribed on a site-specific basis for applicability and effectiveness during
various routine maintenance activities. This project implements all of the relevant BMPs including the
following:
 4.B.5. Replacing the existing culvert with a bridge, a natural bottom system, or a properly
designed and installed culvert is desirable when a high jump and/or the velocity of the water in a
culvert may result in a probable fish migration barrier (usually less than 1 foot).
 4.B.7. For pipes that are to be replaced, design for anadromous fish passage as per the most
recent NMFS and DFG guidelines.
 4.B.8. Minimize disturbance of riparian vegetation during culvert improvement and repair
operations and replace lost plants if needed to provide critical shade cover.
 4.C.1. Size crossings to handle most probable 100-year flood flows and associated debris and
bedloads, given the watershed and specific conditions present in each county. Site-specific
constraints may warrant a different standard.
 4.C.2. See the County Engineer for determining the correct culvert diameter and length for a
given stream crossing to meet hydraulic capacity requirements for flood risk and channel
stability.
 4.C.3. Refer to the latest NMFS and DFG fish passage guidelines and criteria to size replacement
culverts for fish passage in anadromous fish-bearing streams. Consult with NMFS and DFG early
in the design process.
Water Quality Management for National Forest System Lands in California – Best Management
Practices
By conforming to the resource protection measures, Roads Manual BMPs and other design criteria
discussed in this section, the project would also be in conformance with the BMPs established in the
Forest Service Region 5 BMP handbook (USDA Forest service, 2000). The specific BMPs that apply and
would be followed are:





Limiting the Operating Period of Project Activities: 1-5
Erosion Prevention and Control Measures During Project Operations: 1-13
Revegetation of Areas Disturbed by Harvest Activities: 1-15
Streamcourse and Aquatic Protection: 1-19
Erosion Control Structure Maintenance: 1-20
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
















General Guidelines for the Location and Design of Roads: 2-1
Erosion Control Plan: 2-2
Timing of Construction Activities: 2-3
Stabilization of Road Slope Surfaces and Spoil Disposal Areas: 2-4
Road Slope Stabilization Construction Practices: 2-5
Timely Erosion Control Measures on Incomplete Roads & Stream Crossing Projects: 2-9
Construction of Stable Embankments (Fills): 2-10)
Control of Sidecast Material During Construction and Maintenance: 2-11
Servicing and Refueling of Equipment: 2-12
Control of Construction and Maintenance Activities Adjacent to SMZs: 2-13
Controlling In-Channel Excavation: 2-14
2-15 Diversion of Flows Around Construction Sites: 2-15
Bridge and Culvert Installation: 2-17
Disposal of Right-of-Way and Roadside Debris: 2-19
Specifying Riprap Composition: 2-20
Conduct Floodplain Hazard Analysis and Evaluation: 7-2
General Resource Protection Measures
Resource protection measures and design criteria developed to protect and enhance aquatic habitat
conditions and avoid or reduce adverse effects to federally listed species and Forest Service Sensitive fish
and wildlife species are included in the fisheries and wildlife BA/BE documents. A summary of some of
those measures that relate to reducing soil disturbance, impacts to vegetation and the spread of noxious
weeds are included below:
1. There will be no water drafting from streams or the Trinity River.
2. The period of operations shall be between May 15 and October 15. Operations may continue
beyond October 15 with the approval of the Department of Fish and Game and the USFS District
Ranger with consultation with the project hydrologist and/or fisheries biologist, under conditions
where no resource damage related to wet weather are likely to occur.
3. All applicable BMPs for Stream Crossing Replacement listed in the Roads Manual will be
adhered to throughout construction.
4. Ground disturbing activity (heavy equipment use) will not occur during wet weather conditions.
5. Temporary detours that consist of Bailey bridges or similar structures (that do not require
placement of fill material within the stream crossings to construct detour roads) will be used.
6. Permanent and temporary spoils will be stored in a manner to prevent sediment delivery to any
watercourse during and after project construction. All spoils material will be removed from the
construction area prior to October 15 and stored at a Trinity County DOT yard and/or suitable and
approved privately owned sites.
7. All disturbed areas will be revegetated with native grass, forb and tree species immediately
following project construction, including the equipment storage and staging areas, disturbed
stream banks, the access road upstream of Crossing #2 and spoils disposal sites. Equipment
cleaning will be required to reduce the potential for introduction of noxious weeds into the project
area.
8. The project does not include new road construction or decommissioning nor does it include
staging area construction as existing open flat areas will be used for staging and material storage.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Construction
Project construction will be conducted by DOT road crews who have Roads Manual training and prior
experience constructing fish passage improvement projects. Construction is currently scheduled for May 15
through October 15th of the year of construction and will consist of the following general elements:6
1. Pre-, during and post-project photo and water quality monitoring;
2. Pre-construction meeting where the overall project plan, WPCP, Excavation Safety Plan and
applicable Roads Manual BMPs will be discussed;
3. Aquatic species relocation;
4. Vegetation removal;
5. Temporary detour installation;
6. Stream dewatering/temporary diversion installation;
7. Construction;
8. Erosion control and revegetation.
Spill Prevention
DOT shall prepare a spill prevention plan that details precautionary, preventative and spill response
measures sufficient to prevent resource damage from any fuels, lubricants or hydraulic fluids used or
stored on site. The plan shall include provisions for: 1) safely refueling equipment outside the Riparian
Reserve; 2) storing any fuels, lubricants or hydraulic fluids offsite or outside the Riparian Reserve and
contained to prevent accidental spillage if containers are compromised; 3) emergency response measures
adequate to rapidly contain and clean up any spills in a timely manner to prevent dispersal and
contamination of soils or water resources, including onsite availability of a spill kit containing absorbent
pads, booms and a leak-proof container for storing contaminated spill cleanup materials; and 4) a
reporting requirement that the Forest Service and any necessary emergency responders be notified
immediately of any spills, with the stipulation that the spill and all response measures be thoroughly
documented and delivered as soon as possible to the District Ranger. The Forest Service and other
regulatory agencies may order cessation of operations, cleanup and abatement, and/or fines or other
punitive measures if hazardous spills occur.
1. Self contained sewage and grey water facilities will be present and the project operator will
ensure and demonstrate that the sewage containment system is in good operating condition.
2. Temporary concrete wash-out facilities, consisting of a depression or pool constructed of straw
bales or sand bags lined with plastic, will be constructed at the flat staging areas away from the
stream channel. Accumulated concrete waste will be disposed of, along with the plastic liner, in
the County landfill.
Spoils and Fill Material
1. The existing crossings will remain in place until all fill material that could fall into the channel
area is excavated.
2. Excavated fill will not be stored at, or near, the crossing sites but rather will be stored
approximately 300 feet from the channel in a construction staging/storage area and outside of the
100-year floodplain of any stream.
3. If excavated material is to be reused during construction, it will be stored at the existing flat
staging areas to prevent sediment transport towards the stream.
4. All permanent and temporary spoils storage locations and stabilization methods will adhere to the
Roads Manual BMPs.
6 Not all elements are described here, only those relative to soil disturbance and vegetation are included.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
5. Fill that is stored temporarily will be partially compacted in 1-foot lifts by wheel or track rolling
equipment. Water will be required if the soil is not sufficiently wet to partially compact.
6. Stored fill will be covered with plastic tarps sufficient to prevent any rain splash erosion and
secured to prevent release in wind at the end of the work day when any of the following occurs:
a. there is a better than 30% chance of rain within 24 hours;
b. if during rain events, rain splash or surface rilling results in transport of sediment from
the pile to adjacent areas;
c. work is stopped for more than 24 hours;
d. if there are predicted sustained winds greater than 7 mph or wind gusts are causing dust
to rise and transport more than 25 feet from the edge of the pile. Watering can/will be
used for dust abatement in lieu of placing the tarp during work hours.
7. Temporary silt fencing, straw mats, logs and filter fabric will be placed at the base of the work
area to prevent migration of spoils outside the construction footprint. These materials will be left
in place through the first spring following project completion. If feasible, log berm structures
will be left in place after completion of the project.
8. Replaced roadfill and backfill material at both crossings will be compacted to a minimum of 95%
in 6” lifts with adequate soil moisture to assure compaction compliance.
9. Spoils material not planned for re-use will be transported to a pre-approved disposal site and
stored in a manner that prevents any sediment delivery to surface water. Potential storage areas
include Trinity River Restoration Program sites, the Junction City DOT yard or other preapproved locations. Excess spoils material that is endhauled to DOT yard(s) will be sorted and
reprocessed into usable materials as appropriate.
Asphalt Recycling
Asphalt will be recycled and used as road surfacing material for unpaved roads if appropriate.
Groundwater
Any groundwater encountered during excavation or installation of new footings will be pumped away
from the stream and discharged in a vegetated flat area or depression. The vegetation will provide natural
filtration of any sediment in the discharge water before it reaches the stream.
Vegetation removal (clearing & grubbing)
Riparian vegetation, shrubs and conifer/hardwood trees along stream channels at each crossing and on the
fill slopes at Crossing #2 may/will need to be removed, trimmed and/or topped to allow for detour bridge
installation, fill removal, culvert excavation and placement, and/or to provide safe visual sighting
distances. There is no acreage estimate for the amount of expected vegetation removal as only isolated
trees will need to be removed. Approximately 75 trees are identified for removal from the road prism at
Crossing #2. All efforts will be made to reduce the removal of vegetation and trees. Directional felling
will be utilized to reduce impacts to the stream bank and retained vegetation.
Temporary detour installation
At Crossing #1, the detour bridge will be placed immediately downstream of the concrete box culvert and
will conform to the road shoulders. Minor rock placement at the road shoulders to transition the
approaches to/from the bridge will be required. There are no underground or overhead utilities that will
need to be relocated. At Crossing #2, a Bailey bridge will be installed over the crossing after the road
surface and a portion of the fill are excavated to allow for placement. Excavation of the remaining fill
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
and culvert will be completed from the upstream access road (working under the Bailey bridge). The
detour, stream diversion structure(s) and fish screens will be removed prior to October 15.
Erosion control and revegetation
All excavation and placement of roadfill/structural backfill and engineered streambed material will be
done when the active stream is contained within the clean water bypass and with all applicable resource
protection measures and BMPs (silt fencing, straw waddles and oil-absorbing booms) in place. The
roadfill at Crossing #2 and all other disturbed areas (staging areas, stream banks, access road upstream of
Crossing #2) will be revegetated with native grass, forb and tree species and mulched with certified weed
free straw, wood mulch or similar suitable native material.
1. Jute rolls shall be securely staked, with full ground contact, around the base of any spoils piles or
stockpiles that are present at the end of each workday or if operations are suspended for the day,
and/or if there is greater than a 30% chance of measurable precipitation.
2. The staging areas and temporary fill storage sites will be reseeded with native grasses and
mulched with woodchips from trees removed during the road excavation, pine needle mulch,
and/or certified weed free straw. Mulch will be placed over a minimum of 90% of the disturbed
area with a depth sufficient to break up rainwater impact but allow for seeding to respond and
sprout though mulch cover.
3. Erosion control mulching consisting of native woodchips from trees removed during the road
excavation, pine needle mulch, and/or certified weed free straw will be placed over a minimum of
90% of the disturbed area with a depth sufficient to break up rainwater impact but allow for
seeding to respond and sprout though mulch cover.
4. Replanting with native grass, shrub and tree species will be done the first fall/winter following
completion of the project.
Monitoring Requirements
5 Counties Monitoring
Project monitoring will be performed by 5C staff to assess construction and BMP implementation
effectiveness as follows:
 Photo point monitoring of before, during construction, and post construction activities.
 Thalweg profile survey before and after the first winter following construction. This monitoring
may extend to additional years depending on 5C monitoring funding levels.
 1st year erosion control effectiveness monitoring consisting of site inspections to track mulch
cover movement, sediment deposition at silt fence lines and evidence of rill or slump
development.
 Revegetation cover and tree/shrub survival rates in the 1st and 2nd year following completion.
Forest Service Monitoring
The Forest Service may conduct monitoring of the project as part of the Regional BMPEP monitoring
program, either as part of the randomly assigned pool or as site-specific selected site monitoring. BMPEP
monitoring includes both implementation and effectiveness monitoring. Site-specific monitoring
typically occurs if erosion problems are perceived or BMP violations are observed. In the instance of the
Conner Creek Fish Passage Improvement Project, it is likely that monitoring will occur, since the BMPEP
protocol for evaluating in-channel construction states that:
“All in-channel construction occurring in flowing or dry streams must be evaluated; up to the point
where 5 evaluations have been completed. Evaluations beyond 5 are optional.”
The following evaluation protocols may be applied to the project:
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011





E09 – Stream Crossings
E12 – Servicing and Refueling
E13 – In-Channel Construction Practices
E15 – Rip Rap Composition
V29 – Revegetation of Surface Disturbed Areas
In addition, administrative or in-channel evaluation protocols may apply to the project if it is selected for
that type of monitoring.
VI. References
Boberg and Kenyon 1979. California Department of Fish and Game Stream Inventory, Trinity County. CA
Department of Fish and Game. Unpublished
Coe, Drew B. R. 2006, Sediment production and delivery from forest roads in the Sierra Nevada,
California, M.S. thesis, Colorado State University, Fort Collins, CO, 110 pp.
California Department of Fish and Game. 2004. Recovery Strategy for California Coho Salmon.
Dunham, Jason B.; Rosenberger, Amanda E.; Luce, Charlie H.; Rieman, Bruce E. 2007. Influences of
wildfire and channel reorganization on spatial and temporal variation in stream temperature and the
distribution of fish and amphibians. Ecosystems: DOI:10.1007/s10021-007-9029-8..
Five Counties Salmonid Conservation Program. 2001. Direct Inventory of Roads and Treatment- Trinity
County Roads. California State Water Resources Control Board, Proposition 204 Program Agreement #9164-250-0.
Water Quality and Stream Habitat Protection Manual for County Road Maintenance in Northwestern
California Watersheds (Roads Manual). www.5counties.org
Gresswell, R.E. 1999. Fire and Aquatic Ecosystems in Forested Biomes of North America. Transactions
of the American Fisheries Society 128:193-221
Interagency SEIS Team, 1994. Standards and guidelines for management of habitat for late-successional
and old-growth forest related species within the range of the northern spotted owl - attachment a to the
record of decision for amendments to forest service and bureau of land management planning documents
within the range of the northern spotted owl, Portland, OR.
Haskins, Donald M. 1983. An overview of the use of cumulative watershed impact analysis, ShastaTrinity National Forest. Shasta-Trinity National Forest, unpublished.
Jordan, Christine J. 2011. Fisheries Biological Assessment and Evaluation. Conner Creek Fish Passage
Improvement Project. Prepared on behalf of the Trinity County Department of Transportation.
Neary, Daniel G., Kevin C. Ryan, and Leonard F. DeBano, eds. 2005. Wildland fire in ecosystems: effects
of fire on soils and water. Gen. Tech. Rep. RMRS-GTR-42-vol. 4. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Research Station. 250 pp.
North Coast Regional Water Quality Control Board (NCRWQCB), 2007 Water Quality Control Plan for
the North Coast Region, Basin Plan.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
SHN, 2006. Fish Passage Design for Conner Creek at Red Hill Road and Conner Creek Road. Five
Counties Salmonid Conservation Program under CA Coastal Conservancy Grants 05030 and 08090.
Unpublished.
Taber Geo-Technical. Foundation Report for Conner Creek Road. Five Counties Salmonid Conservation
Program under CA Coastal Conservancy Grant 08090. Unpublished.
Taylor, Ross, M. Love, T. Grey, and A. Knoche. 2002. Final Report: Trinity County Culvert Inventory
and Fish Passage Evaluation. Five Counties Salmonid Conservation Program.
USDA Forest Service, 1994. Final Environmental Impact Statement, Shasta-Trinity National Forests Land
and Resource Management Plan. Pacific Southwest Region.
USDA Forest Service, 1995. Shasta-Trinity National Forests Land and Resource Management Plan.
Pacific Southwest Region.
USDA Forest Service, 2000. Water Quality Management for National Forest System Lands in California
– Best Management Practices. Pacific Southwest Region, Vallejo, CA.
USDA Forest Service, 2002. Best Management Practices Evaluation Program (BMPEP) User’s Guide.
Pacific Southwest Region.
USDA Forest Service, 2008. Hydrology Resource Assessment, Iron Complex. Shasta-Trinity National
Forest BAER Team – Brad Rust, Team Leader; Angela Coleman and Steve Bachmann, Hydrologists.
USDA Forest Service 2009a, Watershed Analysis, Burnt Ranch and Soldier Creek Planning Watersheds,
Trinity River Management Unit, Shasta-Trinity National Forest, Trinity County, California, unpublished
document, 71 pp.
USDA Forest Service, 2009b. Shasta-Trinity CWE 2009 Cumulative Watershed Effects Analysis, ShastaTrinity National Forest, November 2008. Analysis by Don Elder, ACT2 Enterprise Team.
USEPA 2001, Trinity River Total Maximum Daily Load for Sediment, U.S. Environmental Protection
Agency Region IX, 77 pp.
Zeimer, R.R., 1981. Roots and the stability of steep slopes, in Symposium on Erosion and Sediment
Transport in Pacific Rim Steeplands, p. 343-357.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Appendix A
Best Management Practices from the “Water Quality and Stream Habitat
Protection Manual for County Road Maintenance in Northwestern California
Watersheds” (Roads Manual)
Select BMP sections from the Roads Manual are provided here for reference.
4.A.2. During any in-water work, minimize sediment impacts and ensure that no fish stranding occurs
[see: 4-F Temporary Stream Diversions and Appendix B-8 and B-9].
4.B.8. Minimize disturbance of riparian vegetation during culvert improvement and repair operations and
replace lost plants if needed to provide critical shade cover.
4.C.1. Size crossings to handle most probable 100-year flood flows and associated debris and bedload,
given the watershed and specific conditions present in each county. Site-specific constraints may warrant
a different standard.
4.C.2. See the County Engineer for determining the correct culvert diameter and length for a given
stream crossing to meet hydraulic capacity requirements for flood risk and channel stability.
4.C.3. Refer to the latest NMFS and DFG fish passage guidelines and criteria to size replacement culverts
for fish passage in anadromous fish-bearing streams. Consult with NMFS and DFG early in the design
process [see Appendix C].
4.D.1. Consider a single span bridge as the first option for culvert replacement in anadromous fish
bearing streams. Bottomless arch culverts or partially buried “embedded” culverts are preferred over
non-embedded culverts for fish passage purposes. Baffled culverts or fishways (> 0.5% slope) are the
least preferred of the passage improvements.
4.D. 4. Ensure that all replacement culverts on anadromous fish-bearing streams meet the most recent
version of the NMFS & CDFG fish passage criteria and guidelines. Variances can be allowed where
meeting the guidelines can be shown to be unreasonable or impractical, based on biological and/or
hydrologic rationale.
4.D.5. Have the County Engineer evaluate the site to be sure that the proposed replacement structure
will not increase the flood risk or cause sediment routing problems.
4.D.6. Only install replacement culverts in a dewatered site, with a sediment and flow routing plan [see:
4-F Temporary Stream Diversions].
4.D.7. Store excavated spoils and equipment in a location that will prevent sediment delivery to
watercourses [see: Chapter 5 - Spoil Disposal].
4.D.8. Maintain equipment to prevent leaks that may reach streams and clean before use near
watercourses. Keep all fuel storage and staging materials out of the riparian area.
4.D.9. Place spill contingency resources to contain a small to moderate spill (1-10 gallons) at each job
site where equipment is used. Install oil absorbent materials downstream of in-water work sites to trap
accidental spills or leaks into streams from equipment. Keep a Notification Checklist for hazardous spills
on site and use if spill into stream occurs [see: 8-C Accident Clean-up].
4.D.10. Fully restore disturbed sites within the riparian area with a mix of native, riparian plant species
where disturbance of the shade canopy was significant due to the replacement project. If bare dirt sites
result, apply erosion control measures [see: Appendix B-4].
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
4.D.11. To design for the possibility of conduit failure due to blockage or other problem, include
additional surface routes which will redirect flood waters into the natural drainage course at non-erosive
velocities as soon as possible.
4.D.12. Align culverts and other structures with the stream, with no abrupt changes in flow direction
upstream or downstream of the crossing. This can often be accommodated by changes in road alignment
or slight elongation of the culvert.
4.D.13. Place bottomless arches and embedded culverts at or near the same gradient as the natural
streambed and wider than the active stream channel. The active channel is considered to be the wetted
channel up to the ordinary high water marks. Minimize the possibility that the new culvert will not cause
any existing downstream channel enlargement to migrate upstream.
4.D.14. At stream crossings, place embedded culverts at least one foot deeper than the streambed grade,
or embedded at least 20% of its height; whichever is greater. If the culvert is placed too low, the inlet can
easily plug and overflow. If the culvert is placed too high in the fill, flow could potentially undercut the
inlet, and erode the streambed and fill at the outlet.
4.D.15. Protect both the inlet and the outlet with armor to protect from scour, if feasible [see: Appendix
B-3].
4.F. 1. Make sure the temporary diversion channel is capable of carrying the anticipated streamflows
during the construction period.
4.F. 2. Where anadromous fish are present, work closely with a qualified agency or consulting fishery
biologist who has the needed permits. For listed species, the incidental and direct take permits will require
reasonable and prudent measures (RPMs) to be used. Follow these permit requirements under the
supervision of the fishery biologist.
4.F. 3. Have the supervising biologist remove all fish out of the affected area before dewatering any
stream section. If fish are still found stranded in the dewatered channel, immediately transport them to
the active channel following the directions of the biologist (usually by netting, electrofishing and/or
pumping the fish with an approved fish-friendly method).
4.F. 4. Complete the diversion before or after typical upstream fish migration periods (see Table 1-2 and
ask local DFG fishery biologist for local timing). If this is not possible, install a diversion pipe capable of
passing fish or other method approved by DFG [see: Appendix B-3.4 for baffle designs].
4.F. 5. Maintain fish passage in the new channel at all times and make sure that the water pumping
hose/culvert has an adequate screen to avoid fish entrainment, unless otherwise approved by NMFS and
DFG [see: 3-B-3 Water Drafting for temporary screening practices].
4.F. 6. Isolate the diversion channel from the natural channel during excavation.
4.F. 7. For each job site where equipment is used:
a) Install oil absorbent materials downstream of in-water work sites to trap accidental spills or leaks
into streams from equipment. Store excavated spoils and equipment to prevent sediment delivery
to watercourses [see: Chapter 5 – Spoil Disposal].
b) Ensure spill contingency resources to contain a small to moderate spill (1-10 gallons) are in place.
4.F. 8. Line diversion channel with filter fabric, visqueen or a similar material and anchor with rock or
sandbags to hold it in place. The purpose is to prevent the bed and banks of the diversion channel from
eroding at expected flows.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
4.F. 9. When diverting the flow into the temporary channel, first remove the downstream plug of the
temporary channel, followed by the upstream plug. Next, close the upstream end of the natural channel
and then close the downstream end.
4.F.10. If a tributary enters the former channel within the diversion area, connect the tributary to the new
dewatering channel. If any channel change is done to intercept a tributary, move the channel back to its
original shape and location at the completion of the temporary diversion.
4.F.11. To restore flow to the natural channel, first remove the downstream and then the upstream plug of
the natural channel. Next, close the upstream end and the then the downstream end of the diversion
channel.
4.F.12. After removing any man-made material, backfill the diversion channel and stabilize the stream
banks. Revegetate disturbed riparian areas with naturally occurring plants and grasses.
4.F.13. An alternative to a temporary stream diversion channel is to impound the flow and transport the
flow around the site via pumps and piping. This practice requires screening of the stream at the pumps
and removal of any fish from the dewatered site after installing fish blocking screens above and below the
site.
5.A.1. Determine the location of existing disposal sites, potential disposal sites, and locations of
significant spoil generation along county roads. Incorporate data collected from County Road Erosion
Inventory as much as possible.
a. Conduct site investigations of existing and potentially suitable County disposal sites. Site
investigations should include the disposal area size, distance to watercourses, potential slope
instabilities, listed species habitat, archaeological sites, nearby residential areas, access, and other
limiting factors.
b. Prepare a map and data set indicating sites (existing and potential) with acceptable site
characteristics (see below). Prioritize acceptable sites and initiate the permitting process.
c. Develop site plans for sites adjacent to or near riparian areas or streams to identify erosion and
sediment control needs, and to ensure stability of the material.
5.A. 2.
a.
b.
c.
Follow these acceptable site characteristics in the site election & design process:
Seek a stable site where sediment cannot reach the stream during any high water event.
Avoid adjacent riparian corridors or any area within the 100-year floodplain.
Avoid all wetland sites as these sites are protected from disposal activities and permits will be
required and may not be granted.
d. Avoid placing spoil on unstable slopes, where the added weight could trigger a land movement.
Excessive loading of clay or silt soils could also trigger a failure.
e. Use wide, stable locations such as rock pits, ridges, and benches as places to dispose of fill.
Avoid locations where ground water emerges or a thick organic layer is present.
f. Avoid sites with endangered or threatened plant species. Search the California Natural Diversity
Database [//www.dfg.ca.gov/whdab/html/cnddb.html] for any known listed plant sites in the area.
Seek site evaluations by qualified botanists during the appropriate season before selecting a new
site.
5.A.2.1. Avoid placing excess spoils into stream courses and adjacent riparian zones where it could
potentially result in sediment delivery to streams.
5.A.2.2. Drain spoil piles to prevent the concentration of flow and to prevent rill and gully erosion.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
5.A.2.3. Spread material not to be re-used in compacted layers and generally conforming to the local
topography.
5.A.2.4. Separate organic material (e.g., roots, stumps) from the dirt fill and store separately. Place this
material in long-term, upland storage sites, as it cannot be used for fill. Leave all organic material that
can safely remain in adjacent riparian zones. Make stored woody debris available to others as large wood
for placement in streams for habitat improvement.
5.A.2.5. Store “clean” material in a short-term disposal site (stockpile) if it will likely be re-used for fill
or shoulder widening projects. Verify if material can be used for shoulder widening. [See: 5-B-1]
5.A.2.6. Where feasible, recycle asphalt material in embankments and shoulder backing. Place these
materials where they will not enter the stream system. Asphalt that is 5 years old is considered “inert”
(that is, all oils washed off).
5.A.2.7. Encourage stockpiling and reusing concrete materials when possible [see: 5-B-1].
5.A.3.1. Do not add excess unusable material to permanently closed sites.
1. Spread material not to be re-used in compacted layers, generally conforming to the local topography.
2. Design the final disposal site reclamation topography to minimize the discharge of concentrated
surface water and sediment off the site and into nearby watercourses.
3. Cover the compacted surfaces with a 6-inch layer of organic or fine-grained soil, if feasible.
4. After placement of the soil layer, track-walk the slopes perpendicular to the contour to stabilize the
soil until vegetation is established. Track walking creates indentations that trap seed and decrease
erosion of the reclaimed surfaces.
5. Revegetate the disposal site with a mix of native plant species. Cover the seeded and planted areas
with straw compost, mulched with straw at a rate of 1 to 1 ½ tons per acre. Apply jute netting or
similar erosion control fabric on slopes greater than 2:1 if site is erosive.
5-B-1
Keep temporary disposal sites out of wetlands, adjacent riparian corridors, and ordinary high water areas
as well as high risk zones, such as 100-year floodplain and unstable slopes.
Anticipate sufficient storage area with no risk for sediment delivery for piles that may slump. Stress
cracks indicate that the pile is at risk of slumping. See figure below.
Follow BMPs in 6-D-4 (Outdoor Storage of Raw Materials), where possible.
Reuse and recycle concrete, asphalt, and other construction waste when possible.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Source: Choctawhatchee, Pea & Yellow Rivers Watershed Management Authority (2000)
1. 8-c-4 For spills on roadways:
a) Contain spill so it does not enter flowing waters of the stream system, including the storm drain
system along the roads;
b) Ensure that each county road project site contains spill clean-up/ emergency response kits with
sufficient materials to contain at least a small to moderate spill (1-50 gallons);
c) Minimize further tracking of spilled material.
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Conner Creek Fish Passage Improvement Project - Hydrology Report – June 15, 2011
Appendix B
Northwest Forest Plan Aquatic Conservation Strategy (ACS)
Northwest Forest Plan Aquatic Conservation Strategy (ACS): The project will implement Riparian
Reserves, the Aquatic Conservation Strategy Objectives and Riparian Management (Prescription 9)
objectives as follows:
 Maintain and restore the physical integrity of the aquatic system, including shorelines, banks
and bottom configurations (page 4-53).
 Cooperate with Federal, state, and county agencies to achieve consistency in road design,
operation, and maintenance necessary to attain Aquatic Conservation Strategy Objectives
(page 4-54).
 New culverts, bridges and other stream crossings shall be constructed, and existing culverts,
bridges and other stream crossings determined to pose a substantial risk to riparian conditions
will be improved, to accommodate at least the 100-year flood, including associated bedload
and debris. Priority for upgrading will be based on the potential impact and the ecological
value of the riparian resources affected. Crossings will be constructed and maintained to
prevent diversion of streamflow out of the channel and down the road in the event of crossing
failure (page 4-55).
 Provide and maintain fish passage at all road crossings of existing and potential fish-bearing
streams (page 4-55).
 Design and implement watershed restoration projects in a manner that promotes long-term
ecological integrity of ecosystems, conserves the genetic integrity of native species and
attains Aquatic Conservation Strategy objectives (page 4-58).
 Cooperate with other federal, state, local, and tribal agencies, and private landowners to
develop watershed-based Coordinated Resource Management Plans or other cooperative
agreements to meet Aquatic Conservation Strategy Objectives (page 4-58).
Design and implement fish and wildlife habitat restoration and enhancement activities in a manner that
contributes to attainment of Aquatic Conservation Strategy objectives (page 4-58).
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