California Department of Transportation ( Caltrans)
District 1 Pilot Fish Passage Assessment Study:
Volume 1 – Overall Results
FHWA/ CA/ EN- 2005/ 02
Margaret M. Lang
Environmental Resources Engineering
Humboldt State University
Final Report For Project:
F 2001 EN 10
Researching State Highway Culverts to Determine Impacts on Threatened
and Endangered Salmon
i
California Department of Transportation
( Caltrans) District 1 Pilot Fish Passage
Assessment Study: Volume 1 – Overall Results
Margaret M. Lang
Environmental Resources Engineering
Humboldt State University
February 14, 2005
FINAL TECHNICAL REPORT
Submitted to California Department of Transportation for the project: F 2001 EN 10 Researching State
Highway Culverts to Determine Impacts on Threatened and Endangered Salmonids
ii
STATE OF CALIFORNIA DEPARTMENT OF TRANSPORTATION
TECHNICAL REPORT DOCUMENTATION PAGE
TR0003 ( REV. 10/ 98)
1. REPORT NUMBER
FHWA/ CA/ EN- 2005/ 02
2. GOVERNMENT ASSOCIATION NUMBER
3. RECIPIENT’S CATALOG NUMBER
5. REPORT DATE
February 14, 2005
4. TITLE AND SUBTITLE
California Department of Transportation ( Caltrans) District 1 Pilot
Fish Passage Assessment Study: Volume 1 – Overall Results 6. PERFORMING ORGANIZATION CODE
7. AUTHOR( S)
Margaret M. Lang
Environmental Resources Engineering
Humboldt State University
8. PERFORMING ORGANIZATION REPORT NO.
10. WORK UNIT NUMBER
9. PERFORMING ORGANIZATION NAME AND ADDRESS
California Department of Transportation
Division of Research and Innovation, MS- 83
1227 O Street
Sacramento CA 95814
11. CONTRACT OR GRANT NUMBER
F 2001 EN 10
13. TYPE OF REPORT AND PERIOD COVERED
Final Report
12. SPONSORING AGENCY AND ADDRESS
California Department of Transportation
Sacramento, CA 95819
14. SPONSORING AGENCY CODE
15. SUPPLEMENTAL NOTES
This project was performed in cooperation with the US Department of Transportation, Federal Highway
Administration. This is the final report for the project entitled: Researching State Highway Culverts to Determine
Impacts on Threatened and Endangered Salmon
16. ABSTRACT
In March of 2001, the California Department of Transportation ( Caltrans) initiated the North Coast Pilot Research
Study to identify State Highway System culverts that blocked or impeded upstream or downstream passage of
anadromous salmonids. The geographic limits of the pilot study were the coastal counties of Del Norte,
Humboldt, and Mendocino in Caltrans District 1. More than 800 miles of State Highway were evaluated and 411
potential fish passage sites were identified. Consultation with fisheries professionals subsequently eliminated 78
of these sites because they did not support fish. As of December 1, 2004, 312 of these sites have been
surveyed and analyzed using the California Department of Fish and Game’s assessment protocol ( Taylor and
Love, 2003) to identify potential impediments to fish passage including high water velocities, low water depths
and excessive leaps over the range of fish passage flows. The remaining 21 sites were not surveyed because
landowners denied access to the sites. Fish passage analysis of the 312 surveyed sites shows that 186 or 60%
do not meet current fish passage guidelines for existing culverts and present a severe impediment to fish
passage, 99 sites ( 32%) are likely to present difficult passage conditions under some conditions or for some of
the target fish; and 27 sites ( 9%) provide good passage conditions for all species and lifestages of fish over the
full range of fish passage flows.
17. KEY WORDS
fish passage, culvert, road crossing, salmonid
restoration
18. DISTRIBUTION STATEMENT
No restrictions. This document is available to the
public through the National Technical Information
Service, Springfield, VA 22161
19. SECURITY CLASSIFICATION ( of this report)
Unclassified
20. NUMBER OF PAGES
198
21. PRICE
Reproduction of completed page authorized
iii
TABLE OF CONTENTS
LIST OF FIGURES…………………………………………………………….…….. iv
LIST OF TABLES…………………………………………………………….………. v
EXECUTIVE SUMMARY……………………………………………………………. vii
ACKNOWLEDGMENTS…………………………………………………………….. viii
1 INTRODUCTION..................................................................................................... 1
1.1 PROJECT JUSTIFICATION....................................................................................... 3
1.2 PROJECT DESCRIPTION......................................................................................... 5
1.3 PROJECT PRODUCTS............................................................................................. 6
1.4 REPORT ORGANIZATION ...................................................................................... 7
2 METHODS AND BACKGROUND........................................................................ 8
2.1 IDENTIFYING POTENTIAL FISH PASSAGE SITES .................................................... 8
2.2 FIRST PASS SURVEYS........................................................................................... 9
2.3 SITE ACCESS ...................................................................................................... 10
2.4 SECOND PASS SURVEYS..................................................................................... 10
2.5 SITE DATA PROCESSING..................................................................................... 17
2.6 FISH PASSAGE ANALYSIS USING THE CDFG FILTER.......................................... 17
2.7 SITE- SPECIFIC HYDROLOGY: FISH PASSAGE DESIGN FLOWS AND PEAK FLOWS21
2.8 FISHXING ANALYSES......................................................................................... 27
2.9 FISH PRESENCE AND HABITAT INFORMATION.................................................... 28
2.10 PRIORITIZATION................................................................................................. 29
3 RESULTS ................................................................................................................ 33
3.1 SURVEY SUMMARIES ......................................................................................... 33
3.2 CDFG RANKING MATRIX RESULTS................................................................... 33
3.3 PRIORITIZATION................................................................................................. 35
3.4 COMPARISON OF CALTRANS AND COUNTY PRIORITIZATIONS............................ 46
4 RECOMMENDATIONS AND IMPLEMENTATION....................................... 52
5 REFERENCES........................................................................................................ 53
6 APPENDICES
iv
LIST OF FIGURES
FIGURE 2.1. DIAGRAM OF REQUIRED SURVEY POINTS THROUGH A CULVERT AT A TYPICAL
STREAM CROSSING ( TAYLOR AND LOVE, 2003). ........................................................ 12
FIGURE 2.2. ROAD FILL MEASUREMENTS ( MODIFIED FROM TAYLOR AND LOVE, 2003). .. 13
FIGURE 2. 3. CONCRETE ARCH CULVERT WITH A CONCRETE INLET APRON AND DEBRIS
WALL.. ....................................................................................................................... 14
FIGURE 2.4. THE PICTURE ON THE LEFT SHOWS A CONCRETE OUTLET WEIR WITH A LOW
FLOW NOTCH. THE PICTURE ON THE RIGHT SHOWS MULTIPLE BOULDER WEIRS
INSTALLED TO MITIGATE A PERCHED OUTLET............................................................. 14
FIGURE 2. 5. FISH LADDER ADDED TO A CULVERT OUTLET TO ENHANCE FISH PASSAGE. ... 15
FIGURE 2.6. WINGWALLS AND HEADWALLS GUIDE FLOW INTO CULVERTS AND PROTECT
FILL SLOPES FROM EROSION. ...................................................................................... 15
FIGURE 2.7. ACTIVE CHANNEL WIDTH VERSUS BANKFULL CHANNEL WIDTH ( TAYLOR AND
LOVE, 2003). ............................................................................................................. 17
FIGURE 2.8. GREEN- GRAY- RED CDFG FISH PASSAGE ASSESSMENT RANKING FILTER
( TAYLOR AND LOVE, 2003). ...................................................................................... 20
FIGURE 2.9. MEASUREMENTS USED IN GREEN- GRAY- RED FILTERING CRITERIA ( TAYLOR
AND LOVE, 2003)....................................................................................................... 21
FIGURE 2.10. SAMPLE REGIONAL FLOW DURATION CURVE ( FDC) FOR DEL NORTE 101.... 24
FIGURE 2.11. CALIFORNIA REGIONAL REGRESSION EQUATIONS FOR ESTIMATING PEAK
FLOWS ASSOCIATED WITH A 2- YEAR, 5- YEAR, 10- YEAR, 25- YEAR, 50- YEAR, AND 100-
YEAR RECURRENCE INTERVAL ( WAANANEN AND CRIPPEN, 1977)............................. 26
v
LIST OF TABLES
TABLE 1.1. DEFINITIONS OF BARRIER TYPES AND THEIR POTENTIAL IMPACTS ( TAYLOR AND
LOVE, 2003). ............................................................................................................... 4
TABLE 2.1. CALIFORNIA FISH PASSAGE DESIGN FLOWS ( CDFG 2002, NMFS 2001)......... 22
TABLE 2.2 FISH SPECIES AND LIFE STAGES USED IN THE FISH PASSAGE ALONG WITH
ASSOCIATED SWIMMING ABILITIES AND PASSAGE CRITERIA. ...................................... 28
TABLE 3.1. CDFG RANKING MATRIX SUMMARY FOR CALTRANS DISTRICT 1 POTENTIAL
FISH PASSAGE STREAM CROSSINGS. ............................................................................ 34
TABLE 3.2. TOP 25 PRIORITY SITES FOR FISH PASSAGE REMEDIATION IN CALTRANS
DISTRICT 1................................................................................................................. 37
TABLE 3.3. TOP 10 PRIORITY SITES FOR FISH PASSAGE REMEDIATION IN DEL NORTE
COUNTY..................................................................................................................... 41
TABLE 3.4. TOP 10 PRIORITY SITES FOR FISH PASSAGE REMEDIATION IN HUMBOLDT
COUNTY..................................................................................................................... 43
TABLE 3.5. TOP 10 PRIORITY SITES FOR FISH PASSAGE REMEDIATION IN MENDOCINO
COUNTY..................................................................................................................... 45
TABLE 3.6. COMPARISON OF DEL NORTE COUNTY STREAM CROSSINGS PRIORITIZATION TO
CALTRANS. ................................................................................................................ 47
TABLE 3.7 COMPARISON OF HUMBOLDT COUNTY STREAM CROSSINGS PRIORITIZATION TO
CALTRANS. ................................................................................................................ 49
TABLE 3.8 COMPARISON OF MENDOCINO COUNTY STREAM CROSSINGS PRIORITIZATION TO
CALTRANS. ................................................................................................................ 51
vi
Disclaimer
The contents of this report reflect the views of the authors who are responsible for the facts and
accuracy of the data presented herein. The contents do not necessarily reflect the official views or
policies of the State of California or the Federal Highway Administration. This report does not
constitute a standard, specification, or regulation.
vii
EXECUTIVE SUMMARY
In March of 2001, the California Department of Transportation ( Caltrans) initiated the
North Coast Pilot Research Study to identify State Highway System culverts that blocked
or impeded upstream or downstream passage of anadromous salmonids. The geographic
limits of the pilot study were the coastal counties of Del Norte, Humboldt, and
Mendocino in Caltrans District 1. More than 800 miles of State Highway were evaluated
and 411 potential fish passage sites were identified. Consultation with fisheries
professionals subsequently eliminated 78 of these sites because they did not support fish.
As of December 1, 2004, 312 of these sites have been surveyed and analyzed using the
California Department of Fish and Game’s assessment protocol ( Taylor and Love, 2003)
to identify potential impediments to fish passage including high water velocities, low
water depths and excessive leaps over the range of fish passage flows. The fish passage
assessment at all surveyed sites was used to develop a prioritized list of stream crossing
sites needing remediation for fish passage in Caltrans District 1.
The prioritization list for stream crossing remediation on State Highways in Caltrans
District 1 is not a definitive order for which remediation projects should be planned and
addressed but a guidance document identifying sites needing remediation and ranking
high for either species diversity, extent of barrier, habitat or some combination of these
conditions. The data upon which the prioritizations are based is very reliable with the
exception of the upstream habitat quantity and quality values for those sites lacking on
the ground habitat surveys and relying on habitat estimates using topographic maps. The
habitat quality and quantity is a major factor in the prioritization process but given the
access requirements for stream habitat surveys currently in place in California these
values cannot be easily obtained or confirmed. Full- scale habitat surveys are
recommended for those sites ranking high on the prioritization list and having only map
estimates of habitat quantity.
While the opportunity for remediation will strongly influence the order of remediation,
the cost is also a major factor and the cost and effort for remediation can vary greatly
from site to site. Passage problems at low slope or slightly perched outlet sites can likely
be addressed by in- barrel and outlet modification without complete crossing replacement.
These sites will likely present more opportunities for remediation than sites requiring full
replacement. The site summaries for each of the top 25 sites in District 1 ( Appendix C)
indicate whether the site fish passage problems are likely to be addressed by moderate or
extensive modifications. Site summaries and similar recommendations for lower ranking
sites are available in the separate route report volumes.
viii
ACKNOWLEDGMENTS
This work would not have been possible without the hard work and dedication of Tom
Grey, Michael Love ( Michael Love and Associates), and the Humboldt State University
students that worked on the field crews and performed data analysis: Mery Apple,
Anthony Clemento, Patrick Donovan, Rangel Gonzales, Brian Hodgson, Jennifer Jenkins,
Allison Lubard- Kelly, Filix Maisch, Greg Orum, Adam Siade, David Stier, Daryl Van
Dyke, Jason Walker, and Joshua Wolf.
Ross Taylor ( Ross Taylor and Associates), Tom Weseloh ( CalTrout) and numerous
California Department of Fish and Game and NOAA Fisheries personnel provided
essential background information, fish presence/ absence confirmation and other
assistance that was invaluable to the project.
The Caltrans project managers, Shawna Abafo and Deborah McKee, provided assistance
with project coordination and connecting with District personnel. Tim Ash and the
District 1 Right of Way engineers assisted with training needs, background information
and land access.
1
1 INTRODUCTION
The California Department of Transportation ( Caltrans) initiated the Pilot Fish Passage
Assessment Study in March 2001. The study area consisted of northern California State
Highway routes in Del Norte, Humboldt and Mendocino counties ( Caltrans District 1).
The purpose of this study was to identify State Highway stream crossings on fish- bearing
streams and to assess these sites to determine whether they meet the California
Department of Fish and Game and the NOAA- Fisheries requirements for passage of
resident and anadromous salmonids at road- stream crossings ( California Department of
Fish and Game 2002; NOAA- Fisheries 2001). Note, that throughout this report the term
stream crossing is used to refer to human- made structures that cross over or through a
stream channel. For the purpose of this study, the stream crossing structures that were
evaluated consisted of culverts and bridges. Emphasis was given to those streams that
historically or presently support State and federally- listed [ California and Federal
Endangered Species Act( s)] anadromous and non- anadromous salmonid populations.
Specific study objectives were to:
1) Identify State Highway culverts that block passage of threatened or endangered
salmonids in California.
2) Estimate the stream length of salmonid habitat that could be recovered by
restoring fish passage at State Highway culverts.
3) Develop a prioritized list of State Highway culverts needing to be replaced or
repaired to facilitate passage of threatened and endangered salmonids.
4) Develop a GPS database and a GIS application for identifying and spatially
locating State Highway culverts that potentially impact passage for endangered
and threatened salmonids.
5) Use the GPS database and GIS application in the planning stages of STIP, SHOPP
and Maintenance projects to determine which projects may impact threatened and
endangered salmonids, to identify remediation projects that could restore fish
passage, and to facilitate the environmental study and mitigation process.
It is well established that resident and anadromous salmonids need to have free access to
and from streams as well as unimpaired movement within a stream in order to access
suitable habitat. Barriers to migration affect the ease and extent to which these fish can
reach required habitat conditions that in turn, affect an individual’s likelihood for survival
and ultimately, a population’s viability. Barriers are defined as any obstacle that prevents
or impedes fish from successful passage upstream or downstream ( Evans and Johnson
1972), and can be natural or man- made. Some examples of natural barriers are
waterfalls, debris jams, or temperature barriers. Artificial, or man- made, barriers to
salmonid migration include stream crossings, irrigation diversions and dams. Culverts
are a major category of stream crossing structures that can impede or block the movement
of fish within a stream. Culverts that are not properly sized, installed, or maintained can
cause passage problems such as excessive water velocities through the culvert,
downstream channel scour, perched culvert outlets, lack of water depth within a culvert
and debris accumulation. These kinds of changes in stream channel morphology and
2
channel / culvert hydraulic conditions can cause severe impediments to fish migration
and movement within a stream or watershed.
The identification, prioritization, and treatment of migration barriers is considered a vital
step towards recovering salmonid populations by restoring ecological connectivity ( Roni
et al. 2002). Most culverts are located on small streams ( with larger rivers crossed by
span- bridges). Individually, an impassable culvert may block no more than a mile or less
of habitat. However, culverts are widely distributed over the landscape. Stream crossings
by transportation systems, primarily roads and railroads, influence thousands of water-courses
with the cumulative potential to block many miles of habitat. Additionally, many
road systems follow major rivers; as such, a single road can cross many of the river’s
rearing and / or spawning tributaries, thus affecting a major portion of the watershed’s
salmonid population( s).
Design and installation of road culverts that provide unimpaired fish passage is not a new
issue. Efforts to develop and incorporate fish passage criteria have been ongoing for
many decades, with two early studies published during the 1950’ s ( McKinley and Webb
1956; Shoemaker 1956). In the 1970’ s, Caltrans ( formerly the Division of Highways)
implemented its own research project in collaboration with the California Department of
Fish and Game for the express purpose of developing design criteria for passing
anadromous salmonids through State Highway drainage structures ( Kay and Lewis
1970). During this same era, the U. S. Forest Service began a series of systematic culvert
inventories and corrections on National Forest lands in California ( Evans and Johnson
1972). The basis for fish passage criteria remained relatively similar to these early works
until recently when the California Department of Fish and Game ( 2002) and NOAA-Fisheries
( NMFS 2001) updated and published new criteria for meeting fish passage
requirements in California. In support of these updated criteria, Caltrans is developing
special design guidance for road drainage structures that will comply with State and
Federal fish passage criteria.
Caltrans has and continues to incorporate fish passage design requirements during project
development for routine maintenance activities, road rehabilitation projects, and for
major road construction projects. Despite improvements in design practices, the
Department’s ability to systematically rehabilitate its road drainage system to meet fish
passage requirements has been limited by its lack of a systematic assessment and
inventory of its highway drainage system for passage rehabilitation needs. As a result,
the Department has been unable to include priorities for fish passage needs during
development and prioritization of routine maintenance and rehabilitation projects.
The North Coast pilot study begins the process of locating and assessing culvert sites
along the State Highway System that impede or block salmonid fish passage and creating
a prioritized inventory for remediation that can be expanded to include the rest of the
coastal highway system and even the entire State. In addition to assisting Caltrans
planning efforts, the prioritization of State Highway stream crossings contributes to a
collaborative effort on a watershed scale with landowners, agencies, and restoration
groups that are similarly working to correct barriers and restore habitat within the same
3
watershed in order to maximize resource benefits. As an example, Del Norte, Humboldt
and Mendocino counties have completed similar assessments and inventories of their
road drainage systems for fish passage needs. These assessments have already been used
to identify priority sites where complementary projects between Caltrans and the counties
would be desirable.
1.1 Project Justification
Improving fish passage at stream crossings is recognized as a key component of salmon
and steelhead restoration efforts. A United States Government Accounting Office report
noted that recent inventories identified over 2,600 culverts that block migrating fish on
Federal Lands in Oregon and Washington, and inventories are not yet complete ( GAO,
2001). Surveys conducted in Oregon and northern California have identified thousands of
stream crossings which act as total or partial barriers to fish passage ( Mirati, 1999;
Taylor, 2000, 2001a, b). The Oregon Department of Fish and Wildlife survey estimates
that more than half of 4,370 State and County culverts on natural water courses pose fish
passage problems ( Mirati, 1999).
A variety of passage problems may exist at a stream crossing to affect the ability of fish
and other aquatic species to migrate. Common problems include:
• Perched culvert outlets,
• Shallow jump pools or outflow that cascades over riprap,
• Insufficient water depth within the culvert barrel,
• Excessive water velocities,
• Debris accumulation at the inlet or within the culvert barrel, and
• Steep channel bed just upstream of the culvert inlet due to deposition upstream of
an undersized culvert.
The effects of these stream crossing conditions can be either temporal, partial or total
blockage ( Table 1.1). For adult salmonids, passage problems include disruption of
spawning migrations, under- utilization of tributary habitat, over- crowding in available
spawning habitat, increasing the likelihood of stress, injury, or predation/ poaching during
migration delays, and limiting the spatial separation of competing species.
4
Table 1.1. Definitions of barrier types and their potential impacts ( Taylor and Love, 2003).
Barrier Category Definition Potential Impacts
Temporal Impassable to all fish some
of the time
Delay in movement beyond the
barrier for some period of time
Partial Impassable to some fish at
all times
Exclusion of certain species and
life stages from portions of a
watershed
Total Impassable to all fish at all
times
Exclusion of all species from
portions of a watershed
If culverts act as temporal or partial barriers and passage eventually succeeds, adult fish
expend excess energy that may result in their death prior to spawning or reductions in the
viability of eggs and offspring. Migrating fish concentrated in pools and stream reaches
below stream crossings are also more vulnerable to predation by a variety of avian and
mammalian species, as well as poaching by humans. Culverts that impede adult passage
also limit the distribution of spawning, often resulting in under seeded headwaters and
superimposition of redds in lower stream reaches.
The effects on juvenile salmonids include limiting fish to downstream stream reaches
which increases competition for food and shelter; cuts off over- wintering habitat in
tributaries; increases predation in culvert outlet pools; or prevents summer migration
from thermally- stressed mainstem channels to cool- water refugia in smaller tributaries.
Current guidelines for new culvert installation aim to provide unimpeded passage for
both adult and juvenile salmonids ( CDFG 2002, NMFS 2001).
Instream movements of juvenile and non- anadromous salmonids are highly variable and
still poorly understood. Juvenile coho salmon spend approximately one year in
freshwater before migrating to the ocean, and juvenile steelhead may rear in freshwater
for up to four years before out- migration; one to two years is common in California.
Because much of their life history is spent in freshwater, juveniles of both species are
highly dependent on instream habitat. For over- wintering juvenile coho, a common
strategy is to migrate out of larger river systems into smaller streams, during late- fall and
early- winter storms. Although reasons for this behavior are not certain, juvenile coho
may migrate upstream to find more suitable overwintering habitat, away from higher
flows and potentially higher turbidity levels found in mainstem channels ( Skeesick 1970;
Cederholm and Scarlett 1981; Tripp and McCart 1983; Tschaplinski and Hartman 1983;
Scarlett and Cederholm 1984; Sandercock 1991; Nickelson et al. 1992). During summer
months in western Washington State, juvenile salmonids that moved upstream grew
faster than both non- moving and downstream moving juveniles, demonstrating that this
behavior may play an important role in the overall heath of the population ( Kahler et al.
2001).
Culvert designs that are intended to provide passage for all anadromous life stages have
been presented in several detailed design manuals developed by various government
agencies that oversee fisheries and road construction and maintenance ( e. g., Bates et al.
5
1999; Poulin 1998; Baker and Votapka 1990). However, culverts continue to act as
barriers to fish passage because:
• Earlier designs tended to target passage of only adult anadromous
salmonids, failing to address the needs of migrating juvenile or non-anadromous
salmonids,
• Culverts designed to provide fish passage have frequently been
incorrectly installed and improperly maintained,
• Changes in stream morphology often create conditions that hinder
fish passage at culverts, and
• Opportunities for improving fish passage are lost due to the
“ emergency” status of culvert replacements following flood events.
1.2 Project Description
Assessing fish passage at stream crossings on State Highways in Caltrans District 1
required the following steps:
1. Locating stream crossings using the Caltrans District 1 Excel culvert database, USGS
topographic maps, and other available information,
2. Visiting each crossing to perform a First Pass Survey to determine whether a site was
a potential fish passage site,
3. Obtaining Permits to Enter to access those sites where entry to private land was
needed to complete the fish passage assessment,
4. Returning to the site to perform a Second Pass Survey and collect all necessary
measurements needed for the fish passage assessment,
5. Performing a preliminary fish passage assessment using culvert specifications and
passage criteria for juvenile, non- anadromous and adult salmonids employing the
California Department of Fish and Game’s ( CDFG) ranking filter ( Taylor and Love,
2003),
6. Applying the computer software program, FishXing V2.2, ( Love et al., 1999) on the
subset of sites defined as partial/ temporal barriers by the ranking filter to determine
the percent of passage provided,
7. Determining fish species presence/ absence and the quality and quantity of stream
habitat above each culvert, and
6
8. Prioritizing the sites using CDFG’s numerical ranking process to identify which sites
have the highest priority for replacement on each State Highway.
The methods used to complete all of these steps are described in detail in Section 2 of this
report.
1.3 Project Products
A number of products result from this research effort and each should assist Caltrans in
incorporating maintenance and fish passage improvement on State Highways. In addition,
all data collected is being transferred to Caltrans in forms suitable for use in database
development. The products resulting from this project include:
1. An inventory and location description of all stream crossings identified as potential
fish passage sites in Caltrans District 1. Site locations were identified by stream
name; State Highway number and postmile; watershed name; USGS Quad name;
CalWater Hydrologic Units and latitude and longitude ( NAD83 datum) collected by a
Global Positioning System ( GPS).
2. For each site, a detailed description of the stream crossing was collected including:
crossing type, length, diameter or height and width, construction materials, inlet and
outlet type, presence and type of additional structures ( e. g. fish ladders, baffles, trash
racks, weirs, etc.), alignment with the stream channel, an estimate of fill volume,
position relative to flow and more.
3. Two surveys were conducted. A longitudinal profile survey through the culvert
including the adjacent stream channel was measured to determine the culvert and
channel slopes and a survey of the culvert’s tailwater cross- section.
4. Information regarding culvert age, wear, and performance was noted, including the
overall condition of the pipe and other site structures.
5. Digital photographs were taken at each stream crossing of the upstream channel,
downstream channel, culvert inlet, culvert outlet and any other unique site features to
provide a visual summary for each site.
6. An evaluation of fish passage at each culvert location using two methods. Fish
passage was assessed at all sites using the ranking filter developed for Part IX of the
California Department of Fish and Game’s ( CDFG) Salmonid Stream Habitat
Restoration Manual ( Taylor and Love, 2003). The filter quickly determined if a
culvert either met fish passage criteria for all species and life stages as defined by
CDFG for the range of migration flows ( GREEN); failed to meet passage criteria for
all species and life stages ( RED); or was a partial/ temporal barrier ( GRAY). For
those sites ranking GREEN or GRAY, FishXing V2.2 ( Love et al. 1999) was used to
conduct in- depth passage evaluations by modeling culvert hydraulics over the range
7
of migration flows and comparing these values with leaping and swimming abilities
of the species and life stages of interest.
7. The quantity and quality of fish habitat above and below each stream crossing was
obtained from habitat surveys conducted by CDFG and other agencies where
available. If no habitat surveys had been conducted, lengths of potential anadromous
habitat were estimated from USGS topographic maps.
8. A prioritized list of stream crossings that need modification or replacement to meet
current design standards for fish passage. General recommendations for providing
unimpeded fish passage for these sites are also provided.
1.4 Report Organization
Results from this assessment effort are extensive and, thus, are not contained in a single
document. This report volume provides the background needed to understand the project,
describes the procedures used to complete fish passage assessment of stream crossings,
and summarizes the overall results of fish passage assessments for Caltrans District 1.
Prioritization results for all District 1 fish passage sites are included and the top 25
priority sites are described in detail. A comparison of assessment results for State
Highways and recent county road surveys in Del Norte, Humboldt, and Mendocino
counties is also included.
Supplementary report volumes for each county/ route ( e. g. Humboldt 101) within District
1 provide more detailed analyses and a site- by- site condition description.
8
2 METHODS AND BACKGROUND
Site identification and fish passage analysis followed the same procedures for each State
Highway in District 1. The tasks required to complete the analyses included:
1. Identify potential fish passage sites,
2. Complete a First Pass Survey to confirm potential fish passage stream crossings,
3. Gain site access permission through Caltrans Right of Way office,
4. Conduct a Second Pass Survey to measure each site’s physical characteristics,
5. Determine site- specific hydrology and low and high fish passage design flow for all
fish passage sites,
6. Process site data,
7. Perform a fish passage assessment using CDFG’s “ Green- Gray- Red” ranking filter
( Taylor and Love, 2003),
8. Analyze hydraulic conditions using FishXing V2 ( Love et al., 1999) for those sites
ranking Green or Gray using CDFG’s ranking filter,
9. Obtain additional fish presence and habitat data from State agencies, tribes, or local
expertise, and
10. Prioritize sites by route for modification or replacement.
Tasks 1 through 3 are unique to assessment of Caltrans’ stream crossings and are
described in detail below. The Second Pass Surveys, passage analyses, and prioritization
( Tasks 5 through 10) were conducted using the methods outlined in Part IX of CDFG’s
California Salmonid Stream Habitat Restoration Manual ( Taylor and Love, 2003).
These methods are briefly described below. Fish passage analyses following the CDFG
protocols are consistent with the current State and Federal guidelines for passage of
anadromous salmonids through existing stream crossings ( CDFG 2002, NMFS 2001).
2.1 Identifying Potential Fish Passage Sites
Several sources of information were used to identify potential fish passage sites on
Caltrans ownership. Caltrans’ District 1 maintenance division provided an Excel database
listing all known culverts on District 1 routes. This database included each culvert’s
postmile, construction and size. The database was used during the First Pass Survey to
identify sites. All culverts greater than 0.6 m ( 24 inches) in size were visually assessed
for the presence of a natural stream channel meeting the criteria:
• Water courses having ordinary high- water widths in excess of 0.6 m ( 2 feet) provided
the stream gradient is less than 20 percent,
• Water courses with documented salmonid use determined by visual observation,
electrofishing, or verification by local biologists,
9
• Water courses on NOAA Fisheries or CDFG's lists of historic coho- and steelhead-bearing
streams, or
• Water courses indicated on 1: 24,000 USGS topographic maps should initially be
assumed fish bearing.
In addition, Caltrans classifies large box culverts as bridges ( bridge type 19). The District
1 bridge list was used to locate these structures ( Caltrans, 2003).
Assessment of stream crossings for county roads has been completed for Del Norte,
Humboldt and Mendocino Counties ( Taylor 2000, Taylor 2001a, Taylor 2001b). Many
county roads cross the same drainages as State Highways; thus, many State Highway
stream crossings were identified in the county reports and fish presence/ absence,
additional barriers and habitat quantity and quality information were taken from the
county reports where available.
Caltrans also works closely with CDFG in restoration projects and CDFG visually
assesses passage problems during habitat surveys. Sites known to have passage problems
or of special concern because of fish species present or active restoration work are well
known to Caltrans biologists. These sites were identified by both Caltrans and CDFG
biologists.
2.2 First Pass Surveys
The First Pass Survey ( FPS) protocol for fish passage assessment is a quick site
assessment to differentiate drainage culverts from those culverts that convey a natural
stream. The original FPS protocol was developed in April 2001. Recognizing that
obtaining access permission for site surveys can be a long process, and that access may
be denied by landowners, the original first pass procedure was modified in 2003 to
collect more site data on the first visit. Stream crossings on District 1 routes, with the
exception of Del Norte 199, were evaluated using the April 2001 version of the First Pass
Survey. Both FPS procedures are described here.
The datasheet used for the April 2001 version of the First Pass Survey is attached
( Appendix A). Data collected for the April 2001 FPS included the site location, basic
culvert characteristics ( size, shape, construction), upstream and downstream channel
slope measured using a clinometer, a brief assessment of habitat and fish presence
adjacent to the stream crossing, access information, and a description of nearby land
ownership. These data were selected to provide planning information to crews returning
to perform the Second Pass Surveys and for Permit to Enter ( PTE) needs.
The information used to conduct the FPS included the District 1 culvert database for the
route of interest, the route bridge list, and a 1: 24,000 USGS topographic map of the
region. The route was driven and all culverts over 0.6 m ( 24 inches) were visually
10
assessed. If the stream channel matched the criteria for a potential fish passage culvert, a
first pass datasheet was completed. If the site was determined to be a drainage culvert or
it did not meet the potential fish passage criteria, the reason it was not considered a fish
passage culvert was recorded on a copy of the culvert database. Location information for
all sites identified as potential fish passage culverts was sent to Caltrans Right of Way
engineers to obtain site access permission to conduct a Second Pass Survey.
The current version of the FPS was developed in 2003 to include additional site
information by moving data previously collected during the Second Pass Survey to the
First Pass Survey. A copy of the current first pass data sheet is also included in Appendix
A. The data added or moved to the FPS included:
• Site selection criteria questions were included on the datasheet,
• More comprehensive site physical data ( tables of culvert materials and
construction),
• Site photographs,
• GPS determination of site location, and
• Additional site data analysis ( drainage area, hydrology).
All routes and sites assessed after May 1, 2003 used the 2003 version of the FPS.
2.3 Site Access
Permission to enter land adjacent to each stream crossing is needed to complete the
Second Pass Survey. Access needs are limited to no more than 50 m directly upstream
and downstream of the crossing in the stream channel; however, this distance generally
extends beyond Caltrans right of way. HSU provided site locations and assisted Caltrans
ROW office in obtaining landowner contact information. Caltrans District 1 ROW office
contacted landowners, tracked landowner responses, and provided HSU with Permit to
Enter letters. For large landowners, such as state and national parks, national forests,
timber companies, etc., access was easily obtained and these sites were surveyed with
little or no delays. Obtaining access permission from small, private landowners proved to
be a long and tedious process and introduced significant delays to the Second Pass
Surveys.
2.4 Second Pass Surveys
The objective of the Second Pass Survey ( SPS) is to measure the physical characteristics
of the stream crossing and the adjacent stream channel needed to assess the site’s fish
passage using CDFG’s ranking filter and, if needed, to perform hydraulic analysis with
FishXing. Most of this data is collected by performing a longitudinal survey through the
culvert that includes the adjacent stream channel. To perform hydraulic modeling, the
11
site’s tailwater control ( the location that controls the water elevation at the culvert outlet)
must also be identified and, if possible, surveyed. The condition of each crossing and any
comments concerning fish observations and stream habitat adjacent to the site were also
noted. At all sites, a minimum of four digital photographs was taken: upstream and
downstream channel and inlet and outlet of the stream crossing. Additional photos were
taken, if needed, to capture unique site features. The latitude and longitude of each site
was determined using GPS. The methods and procedures for making these measurements
are described below and copies of the original ( 2001) and the updated ( 2003) SPS
datasheets are included in Appendix A.
2.4.1 Site Surveys
Surveys at each culvert used a Topcon GTS- 226 total station and all surveys were
conducted in units of meters. The total station’s data logger was used to store survey
coordinates in data files uniquely named to match the site location, e. g. MEN001_ M001-
44 for Mendocino County, State Highway 1, postmile 1.44. All survey notes and site
information was recorded in water- proof notebooks. Copies of the survey notes are stored
in binders with each site’s first and second pass datasheets.
The total station was setup in a location that minimized the number of resections needed
to complete the survey. This site was most often located just below the culvert outlet on
the stream channel margin. To begin a survey, an arbitrary temporary benchmark, usually
an easily reoccupied point on the culvert, was assigned the coordinates: 0m N, 0m E, and
100m Z. All points were collected relative to this arbitrary coordinate system and
temporary benchmarks ( survey pins) were used to perform resections when needed.
The primary survey was a longitudinal profile beginning in the adjacent stream channel
and proceeding either upstream or downstream through the length of the culvert. The
elevation of the following points were measured along the longitudinal profile at all sites
( Figure 2.1):
1. culvert inlet invert ( bottom),
2. culvert outlet invert ( bottom),
3. maximum pool depth within 1.52 m ( 5 ft) of the outlet,
4. outlet pool tailwater control ( TWC),
5. two points in the stream channel upstream of the culvert, and
6. two points in the stream channel downstream of the TWC.
At most sites, additional points along the culvert invert were also measured to detect any
breaks in slope present in the culvert. A break in the culvert slope may create a barrier
within a culvert that is not detected using the average culvert slope. Interior culvert invert
elevations were collected at all sites where a clear view through the culvert could not
determine the absence of breaks in slope.
12
Figure 2.1. Diagram of required survey points through a culvert at a typical stream crossing ( Taylor
and Love, 2003).
In addition to the longitudinal profile, a survey of the channel cross section at the
tailwater control ( TWC) was also collected. If hydraulic analysis is needed, the TWC
cross section is used in FishXing to develop a rating curve ( flow versus water depth) at
the TWC. Locating the TWC is straight forward for those sites with a pool at the outlet.
In this case, the TWC is the channel structure ( log, riffle, boulders, etc.) that controls the
outlet pool water elevation ( Figure 2.1). The TWC cross section is measured
perpendicular to the stream channel at this location. For sites lacking a clear TWC, i. e.
the culvert outlet is at stream grade, a channel cross section within 1.5 – 3 m ( 5 - 10 ft) of
the outlet is measured.
The site survey is also used to obtain an order of magnitude estimate of the fill volume.
This rough estimate of fill volume is used in prioritization of site replacement or
remediation and has two purposes. First, the replacement cost for a culvert site is highly
influenced by the fill volume that must be moved and replaced to access the culvert.
Second, the fill volume can also be an indication of potential consequences should a
culvert fail due to plugging or being undersized allowing flow to overtop the road. The
fill volume represents the potential volume of sediment delivered to the downstream
channel when a crossing fails. Fill elevation can also be used to estimate the culvert flood
capacity or the flow rate through the culvert when the culvert is submerged with an
upstream water depth approaching the top of the fill. These uses of fill volume and
elevation are appropriate for small to moderate fill volumes. Many fill volumes on
Caltrans ownership, especially on State Highway 101, are extremely large and would not
fail by overtopping. For these sites, the fill volume was noted as extremely large and not
surveyed.
At minimum, 10 survey points were used to estimate the fill volume. The five points,
FB1, FB2, FT1, FT2, and FT3 ( Figure 2.2) were measured on both the upstream and
downstream fill slope. These ten points were then used to calculate the lengths ( Ld, Lu,
13
Wr, Wf, and Wc) and slopes ( Sd and Su) indicated in Figure 2.2. The fill volume is
calculated using these values and equations 1 through 4 as outlined on page 12 of the
California Salmonid Stream Habitat Restoration Manual ( Taylor and Love, 2003). These
fill estimates are order of magnitude only and not meant to be used for design or
construction purposes.
Figure 2.2. Road fill measurements ( modified from Taylor and Love, 2003).
Additional site characteristics such as aprons, weirs, fish ladders, headwalls, and
wingwalls, are also surveyed when present. Aprons are concrete structures extending
upstream or downstream from a culvert at the channel culvert interface to control the
flow transition into or out of the culvert ( Figure 2.3). Aprons often have a different slope
than the culvert itself. If the apron is much steeper than the culvert, then it may be the
limiting factor preventing fish passage.
Weirs constructed of concrete or placed boulders ( Figure 2.4) are common at the outlet or
in the stream channel below a culvert outlet. These structures can control water levels
through the culvert and may decrease velocity or outlet pool erosion. Weirs may also act
as barriers to fish passage by requiring fish to leap over the weir for entry into the culvert.
Fish ladders are present at a number of sites to overcome steep outlet slopes or perched
outlets and allow fish access to the culvert ( Figure 2.5). When fish ladders are present, a
longitudinal profile of the ladder is surveyed to determine the slope, length and whether
breaks in slope are present in the ladder.
Headwalls and wingwalls ( Figure 2.6) are typically vertical, concrete structures designed
to guide water into or out of the culvert and to protect the fill slope from erosion. When
present, the boundaries of the headwalls and wingwalls are surveyed to capture their
height, length and alignment with respect to the culvert and channel.
14
Figure 2. 3. Concrete arch culvert with a concrete inlet apron and debris wall. If the apron has a
steeper slope than the culvert, the apron may cause a velocity barrier to fish passage.
Figure 2.4. The picture on the left shows a concrete outlet weir with a low flow notch. The picture on
the right shows multiple boulder weirs installed to mitigate a perched outlet.
15
Figure 2. 5. Fish ladder added to a culvert outlet to enhance fish passage.
Figure 2.6. Wingwalls and headwalls guide flow into culverts and protect fill slopes from erosion.
16
2.4.2 Culvert Measurements and Characterization
In addition to the surveyed points, measurements and characterization of culvert
construction are also collected during the Second Pass Survey. The culvert length does
not need to be measured with a tape ( as described in the CDFG protocols) when using a
total station and was determined from the longitudinal survey coordinates. The culvert
size ( diameter- D or height- H and width- W) was measured to the nearest 0.03 m ( 0.1 ft)
using a tape measure. The type of culvert and the construction materials were confirmed
with the values recorded during the First Pass Survey. The culvert condition was assessed
and any maintenance problems noted and photographed. For metal pipes, the rustline
height is measured using a tape. The rustline height correlates to the winter base flow
water depth through the culvert and can be used as an indicator for undersized culverts.
Rustline heights approaching half the total culvert height often indicate an undersized
culvert.
2.4.3 Culvert Site Location
Each culvert location was defined using the county, route, and postmile and located by
GPS where possible. The latitude and longitude of each site was determined using a
Trimble Pathfinder Pro XR receiver. GPS measurements were collected at the inlet
postmile marker if the culvert was visible from this location. If the culvert was not visible
from the inlet postmile marker, a GPS measurement at the culvert inlet was attempted. In
some cases, the presence of dense trees or a steep canyon prevented a GPS measurement.
In these locations, the site’s latitude and longitude were determined using Terrain
Navigator 2001 by Maptech, Inc. All latitude and longitudes were provided to Caltrans in
the North American 1983 datum ( NAD83).
2.4.4 Channel widths
Comparison of the active channel width to the culvert inlet width indicates whether the
culvert restricts the channel or is undersized. Culverts with widths much less than the
active channel width restrict higher flows causing increased velocities and poor fish
passage conditions. The average active channel width is determined by making five
measurements of active channel width upstream of the culvert, beyond the influence of
any backwatering by the culvert. The active channel is that portion of channel commonly
wetted during most winter storm flows and is identified by a break in rooted vegetation or
moss growth on rocks along the stream margins ( Figure 2.7). Many culvert design
guidelines utilize active channel widths to determine the appropriate widths of new
culvert installations ( CDFG 2002; NMFS 2001; Robison et al. 2000; Bates et al. 1999).
17
Figure 2.7. Active channel width versus bankfull channel width ( Taylor and Love, 2003).
2.5 Site Data Processing
All site and survey data ( FPS and SPS datasheets, surveying notes) were collected on
waterproof paper or notebooks. Original datasheets are stored by county, route and
postmile in binders. An identical binder with copies of all datasheets and notes exists for
each route and is available for off- site analysis.
Much of the data collected during the Second Pass Survey is in electronic form. After
return from the field, the total station and GPS files are downloaded to computer, given
unique names reflecting the county, route and postmile for the site, and converted to
usable formats. The survey data is processed in Excel to calculate the physical
characteristics needed to perform a fish passage assessment using the CDFG ranking
filter ( Section 2.6) and, if needed, hydraulic analysis ( Section 2.8). The GPS files are
checked and stored for later use to develop GIS layers of fish passage culvert locations
and assessment results.
2.6 Fish Passage Analysis using the CDFG Filter
In collaboration with NOAA Fisheries, CDFG developed a ranking filter to quickly
assess fish passage at stream crossings ( Taylor and Love, 2003). The ranking filter
compares the crossing’s physical characteristics ( length, slope, outlet perch, and water
depth) with criteria determined to meet current guidelines for fish passage at existing
stream crossings. The ranking filter was developed for assessment of fish passage for
adult anadromous, adult non- anadromous and juvenile salmonids in California.
18
Comparison of the crossings’ characteristics to the guidelines determines the ranking
level for the site. The ranking levels are:
• GREEN: Conditions assumed adequate for passage of all salmonids, including
the weakest swimming lifestage.
• GRAY: Conditions may not be adequate for all salmonid species or lifestages.
Additional analyses required to determine the extent of barrier for each species
and lifestage.
• RED: Conditions do not meet passage criteria at all flows for the weakest
individuals of the strongest swimming species presumed present.
Passage criteria were selected for the ranking filter by CDFG and NOAA Fisheries and
are intended to accommodate passage of the weaker swimming individuals within each
species and life stage. A culvert ranking RED is not necessarily a complete barrier,
particularly if it barely fails the criteria; however, this culvert does not meet current fish
passage design guidelines ( CDFG 2002; NMFS 2001) and will likely pose a significant
and unacceptable impediment to both adult and juvenile salmonids. Use of the ranking
filter in assessing Caltrans stream crossings is described below. Additional details
concerning the ranking filter are available in the California Salmonid Stream Habitat
Restoration Manual ( Taylor and Love, 2003).
Figure 2.8 shows the ranking filter flow chart. The ranking filter requires five onsite
measurements: average active channel width, culvert inlet width, culvert slope, residual
inlet depth and residual outlet depth. The first two measurements are collected using a
tape measure during the First Pass Survey. The other three measures are calculated from
the longitudinal profile survey conducted during the Second Pass Survey.
The residual inlet and outlet depths ( Figure 2.9) are measures of the minimum water
depth throughout the culvert and whether the outlet is perched, respectively. A positive
residual inlet depth indicates the depth of water that exists throughout the culvert at very
low flows. The residual inlet depth is positive only when the culvert is backwatered,
meaning that the tailwater control elevation is greater than the elevation of the culvert
invert at the inlet. The residual inlet depth is a direct measure of the water depth in the
culvert under very low flow conditions that, if sufficient, allows unimpeded passage for
juveniles during summer low flows. The residual outlet depth measures either the water
depth at the outlet during low flow conditions ( positive residual outlet depth) or the
extent of the outlet perch, or leap, that exists under low flow conditions ( negative outlet
depth). Outlets perched more than 0.6 m ( 2 ft) have been shown to significantly diminish
the ability of adult salmonids to successfully pass through culverts and introduce
significant delay in upstream passage ( Lang et al. 2004).
The ranking filter has two decision pathways that differentiate culverts by the presence or
absence of streambed substrate throughout the culvert. Natural streambed substrate can
improve fish passage by increasing roughness and slowing velocities through the culvert.
19
If the culvert inlet width is much less than the average active channel width, then the
culvert is constricting flow in the channel. This flow constriction causes higher velocities
in the culvert than the adjacent channel and can increase outlet scour or prevent channel
substrate from remaining in the culvert. Culverts with natural streambed substrate and a
culvert inlet width greater than or equal to the active channel width are assumed to have
similar hydraulic conditions to the nearby stream channel at fish passage flows. In the
ranking filter, the culvert inlet width is used to determine whether culverts with natural
substrate bottoms are likely to retain their substrate and how similar culvert velocities
will be to adjacent channel velocities.
In addition to the culvert inlet width, the other factors influencing the ranking of a culvert
with streambed substrate throughout is the presence of an outlet perched greater than 0.6
m ( 2 ft) and sufficient water depth. An outlet perched greater than two feet receives an
automatic Red ranking for any type of culvert and a residual inlet depth less than 0.15 m
( 0.5 ft) will result in a Gray ranking if no outlet perch exists.
For sites without streambed substrate, the culvert slope is one of the primary controls on
the water velocity through the culvert. At slopes greater than 3%, culverts without baffles
or natural substrate to provide roughness are likely to have average velocities greater than
the fishes’ swimming velocities. Culverts with slope greater than 3% and no fish passage
retrofits are ranked Red. Sites with outlets perched greater than 0.6 m ( 2 ft) or insufficient
water depth will rank Red and Gray, respectively, the same as the natural streambed
culvert rankings.
The ranking filter is designed as a quick assessment tool assuming typical construction
and conditions at a stream crossing. If culverts have unique characteristics that could
hinder fish passage other than the criteria used in the ranking filter, these characteristics
should be thoroughly evaluated before adopting the ranking filter result. Additional
assessment is especially important for those sites ranking Green that may subsequently be
interpreted as providing 100% passage.
20
Figure 2.8. GREEN- GRAY- RED CDFG fish passage assessment ranking filter ( Taylor and Love,
2003).
21
Residual Pool Depth = ( Elev Tailwater Control – Elev Pool Bottom)
Residual Outlet Depth = ( Elev Tailwater Control – Elev Culvert Outlet)
( No outlet drop if Outlet Depth > 0)
Residual Inlet Depth = ( Elev Tailwater Control – Elev Culvert Inlet)
Figure 2.9. Measurements used in Green- Gray- Red filtering criteria ( Taylor and Love, 2003).
2.7 Site- Specific Hydrology: Fish Passage Design Flows and Peak Flows
Assessing stream crossings for fish passage requires estimating several stream flow rates:
the lower and upper fish passage design flows for each species and lifestage, and the peak
flow capacity of the crossing. Designing stream crossings to pass all fish at all flows is
widely recognized as technically and economically infeasible ( CDFG 2002; NMFS 2001;
Bates et al. 1999). The flows at which different fish species and lifestages require access
to particular habitats are fish passage design flows. In California fish passage design
flows are defined for adult anadromous, and adult non- anadromous, and juvenile
salmonids ( CDFG 2002, NMFS 2001).
The peak flow capacity of the crossing is used to evaluate a site’s design level and risk of
failure at high flows. Current guidelines recommend all stream crossings pass the flow
22
associated with the 100- year flood without damage to the stream crossing ( NMFS, 2001).
Additionally, infrequently maintained culverts should accommodate the 100- year flood
with an upstream water depth less than or equal to the culvert’s inlet height. CDFG
guidelines require the upstream water surface elevation to not exceed the top of the
culvert inlet for the 10- yr peak flood and headwater should not be greater than 50% of the
culvert height or diameter above the top of the culvert inlet for the 100- yr peak flood
( CDFG, 2002). The CFDG guidelines match Caltrans’ design criteria.
2.7.1 Fish Passage Design Flows
The fish passage design flows ( Table 2.1) are intended to encompass the range of flows
expected to occur during periods when the target fish migrates upstream. At flows below
an upper fish passage design flow, the water velocities must not exceed the fish’s
swimming ability. At flows above a lower fish passage design flow, water depths within
the stream crossing must be adequate for the fish to swim through. These design flows
are commonly defined in terms of exceedance flows derived from flow duration curves
( e. g. Vogel and Fennessey, 1994). An exceedance flow defines the average percent of
time the stream flow exceeds a specified flow. For example, in 1970 the California
Department of Transportation, in conjunction with California Department of Fish and
Game, defined an upper fish passage design flow for adult salmon and steelhead as that
flow which was equaled or exceeded 10% of the time during the period of upstream
migration ( Kay and Lewis, 1970).
Table 2.1. California fish passage design flows ( CDFG 2002, NMFS 2001).
Fish Species or Lifestage Lower Fish Passage Design Flow Upper Fish Passage Design Flow
Adult Anadromous
Salmonids
50% exceedance flow or 3 cfs
whichever is greater
1% exceedance flow or 50% of the
2- year return period flow
Adult Non- Anadromous
Salmonids
90% exceedance flow or 2 cfs
whichever is greater
5% exceedance flow or 30% of the
2- year return period flow
Juvenile Salmonids 95% exceedance flow or 1 cfs
whichever is greater
10% exceedance flow or 10% of
the 2- year return period flow
Ideally, exceedance flows and the fish passage design flows are determined from long
term flow gaging records at the site of interest. Long- term flow records are rarely
available for the small streams likely to have culverts and other common stream crossings
other than bridges. Therefore, hydrologic estimation techniques are used to determine the
exceedance flows for small watersheds. These estimation techniques use the watershed
drainage area, mean annual precipitation ( MAP), and mean annual evapotranspiration
( PET) to correlate the flows in ungaged watersheds to those in nearby gaged watersheds.
The estimation procedure is outlined below and additional details and an example are
available in Improving Fish Passage at Road Crossings ( Lang et al. 2004).
23
For streams in a region of interest, stream flow gages meeting the following criteria are
identified:
• At least 5, and preferably greater than 10, years of continuous daily flow record,
• Drainage area less than 259 km2 ( 100 sq mi) with smaller drainage areas
preferentially selected when available, and
• The gaged watersheds have similar orographic influences on rainfall to the sites of
interest, e. g. FDCs for coastal sites are developed from coastal stream gage
records.
The mean annual discharge for each of the gaged streams is estimated using the regional
runoff regression equation developed by Rantz ( 1968) for coastal streams in northern
California:
R = MAP- 0.4( PET)- 9.1 ( 1)
Qave = 0.07362[ ft3- yr/( s- in- mi2)]* R* A ( 2)
Where:
Qave = mean annual discharge [ ft3/ s]
MAP = mean annual precipitation [ in/ yr]
PET = potential evapotranspiration [ in/ yr]
R = mean annual runoff [ in/ yr]
A = drainage area [ mi2]
For the gaged streams, the basin wide mean annual precipitation ( MAP) was obtained
from PRISM GIS layers ( Oregon Climate Service 2002) and the potential
evapotranspiration ( PET) was obtained from isohyetal maps and tables produced by
Rantz ( 1964). Next, FDCs were constructed for the annual flows in each gaged stream.
The gaged stream flows were then normalized by the mean annual discharge to develop a
single, regional flow duration curve ( Figure 2.10). Regional flow duration curves were
developed for subregions within District 1 having the same climate and were generally
developed for each State Highway or, where needed, a subsection of a State Highway.
24
Figure 2.10. Sample regional flow duration curve ( FDC) for Del Norte 101.
To determine the fish passage design flows for a particular site, Qave was calculated for
each of the study sites using equations ( 1) and ( 2) and then multiplied by the exceedance
flows on the normalized regional flow duration curve to develop an individual site FDC.
The fish passage design flows are the flow rates matching the particular exceedance
percentage for the site of interest. Regional FDCs and the stream gage data used to create
them are presented in the report volumes summarizing results for each route.
2.7.2 Peak Flow Capacity
Peak flows are typically defined in terms of a recurrence interval, or the time interval
matching the probability of a single occurrence of this flow magnitude. A crossing’s peak
flow or flood capacity is used to rank sites for remediation or replacement by recognizing
that undersized crossings have a higher risk of failure. Undersized stream crossings can
also hinder fish passage by concentrating flows and adversely affect sediment transport
and erosion rates in the adjacent stream channel.
To assess peak flow capacity, the culvert’s hydraulic capacity is compared to the site’s
estimated peak flow at recurrence intervals of 2-, 5-, 10-, 25-, 50- and 100- years. The
culvert hydraulic capacity is a function of the shape and cross- sectional area of the
culvert inlet. Culvert capacity was calculated at each site for a headwater depth ( HW)
equal to the culvert inlet height ( D) ( HW/ D = 1). Tables presented in the US Federal
Highways Administration’s Hydraulic Design of Highway Culverts ( Normann et al.,
0.01
0.1
1
10
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
100%
% of time Q/ Qave. is equaled or exceeded
Q/ Qave. ( cfs/ cfs)
Mean Exceedence Flow
Min/ Max Exceedence Flow
25
2001) were used to determine peak flow capacity for circular metal culverts, concrete box
culverts, and metal pipe arch culverts. Peak flow capacities of other culvert shapes and
embedded culverts were determined using either FishXing V2.2 ( Love et al. 1999) or
CulvertMaster V2.0 ( Haestad Methods 2002).
The estimated peak flows for recurrence intervals of 2-, 5-, 10-, 25-, 50-, and 100- years
was determined for each site using regional regression equations ( Waananen and Crippen
1977) ( Figure 2.11). The regression equations are defined for different regions
throughout California and are functions of watershed area, mean annual precipitation and
a watershed altitude index. These regression equations are also included in Caltrans’
Highway Design Manual as Figure 819.2C ( Caltrans 2001).
Use of regression equations inherently assumes that any watershed for which the
recurrence flows are being predicted is similar to those gaged sites from which the
regression equations were developed. Because of these inherent assumptions, regression
method estimates of flow can be subject to large errors. In design analysis, multiple
methods ( e. g. regression equations, rational method, rainfall- runoff models, etc.) are used
to estimate recurrence interval flows. Regression equation estimates are appropriate for
assessment level analyses and screening where the goal is collection and estimation of
reasonable data at minimal costs to evaluate numerous sites. However, these estimates of
recurrence interval flows should not be used exclusively for design level analyses.
The stream crossing’s capacity and estimated peak flows are compared to determine the
crossing’s current capacity. Sites are assigned one of five size categories:
1. equal to or greater than the 100- year flow,
2. between the 50- year and 100- year flows,
3. between the 25- year and 50- year flows,
4. between the 10- year and 25- year flows,
5. between the 5- year and 10- year flows,
6. less than the 5- year storm flow
This information is used in prioritization ( see Section 2.10) for replacement or
remediation with undersized culverts receiving higher priority for replacement ( all other
criteria being equal).
26
Figure 2.11. California regional regression equations for estimating peak flows associated with a 2-
year, 5- year, 10- year, 25- year, 50- year, and 100- year recurrence interval ( Waananen and Crippen,
1977).
27
2.8 FishXing Analyses
FishXing is an interactive software package, developed by the Six Rivers National Forest,
that integrates a culvert design and assessment model for fish passage nested within a
multimedia educational setting ( Love et al. 1999). The model simulates steady- state,
non- uniform hydraulics through a culvert or similar stream crossing predicting a profile
of water depth through the culvert. These water depths and the culvert’s cross- sectional
area are used to calculate the average velocities throughout the culvert. These simulations
are repeated for all the flows of interest, typically the full range of fish passage design
flows. The program also incorporates fisheries inputs including fish species, life stages,
body lengths, and leaping and swimming abilities. FishXing uses the swimming abilities
to determine whether a culvert ( existing or proposed) will accommodate fish passage
over the required range of fish passage design flows. The simulation results identify
specific locations and conditions within the culvert that impede or prevent passage.
Software outputs include water surface profiles and hydraulic variables such as water
depths and average velocities displayed in both tabular and graphical formats.
In addition to the in- culvert conditions, FishXing also predicts the leap heights occurring
over a given range of flows and whether the fish can negotiate these leaps. A fish’s
ability to successfully negotiate a leap is determined by considering the fish’s maximum
leap velocity and the availability of appropriate leap conditions. To make a leap, the
maximum velocity must be great enough to clear the leap height assuming a perfect leap
trajectory. In addition, a pool with sufficient water depth must be present to ensure that
the maximum leap velocity can be attained. Stuart ( 1962) concluded that a pool depth of
at least 1.25 times the leap height is needed to reach swim speeds fast enough to make a
successful leap.
FishXing used the survey elevations and culvert specifications to evaluate passage at sites
defined as “ GRAY” by the CDFG ranking filter for each species and life- stages of
salmonids known to currently or historically reside in the Caltrans District 1. Table 2.2
shows the values used for fish passage assessment with FishXing. These values are the
recommended values from CDFG fish- passage protocol ( Taylor and Love, 2003) and are
conservative values for assessment under the assumption that although many individual
fish will have swimming abilities surpassing those listed, swim speeds and minimum
water depths were selected to ensure stream crossings accommodated passage of weaker
individuals within each species and age class. This assumption is better suited for the
design of new crossings where being conservative hopefully allows for the passage of all
fish. However, for assessment purposes, the use of conservative swimming values and
minimum water depths can result in many sites that allow some the passage of adult
salmonids being identified as total barriers.
28
Table 2.2 Fish species and life stages used in the fish passage along with associated swimming
abilities and passage criteria.
Fish Species/ Age Class
Adult Anadromous
Salmonids
Adult Non- Anadromous
Salmonids
Juvenile
Salmonids
Fish Length 500 mm 200 mm 80 mm
Prolonged Mode
Swim Speed
Time to Exhaustion
5 ft/ sec
30 min
4 ft/ s
30 min
1.5 ft/ s
30 min
Burst Mode
Swim Speed
Time to Exhaustion
10 ft/ sec
5 sec
5.0 ft/ s
5 s
3.0 ft/ s
5 s
Maximum Leaping Speed 15 ft/ sec 6.0ft/ s 4.0 ft/ s
Minimum Required Water Depth 0.8 ft 0.5 ft 0.3 ft
2.9 Fish Presence and Habitat Information
Confirmed presence of fish species of concern and suitable habitat are the dominant
factors for prioritizing sites for remediation or replacement. Fish presence and habitat
quantity and quality is established using all available information including California
Department of Fish and Game surveys, research studies, local fisheries biologists’
expertise and survey crew observations.
2.9.1 Fish Presence
Confirmed presence of fish species of concern in a stream with a crossing is the most
important information when prioritizing sites or replacement or remediation. Fish
presence was verified or assumed using the following sources:
• CDFG reports or files where available
• County reports developed by Ross Taylor and Associates ( Taylor 2000, 2001a
and 2001b)
• Tribal fisheries biologists
• Timber company biologists
• Local knowledge ( CalTrout, watershed groups, interested residents, etc.)
• Presumed fish presence because of easy access from a downstream known fish
bearing water course
29
Streams with culverts are generally small and few CDFG surveys have been conducted in
streams of this size, especially in regions away from the coast. The NMFS California
Anadromous Fish Distributions ( Jones 2000) report for Mendocino and Sonoma counties
summarizes fish presence surveys conducted by CDFG up to 2000 and provided a great
deal of current and historic data. CDFG files were also searched in the Ukiah, Fortuna
and Arcata offices for fish and habitat survey data.
2.9.2 Habitat Information
Because access to stream channels was limited to the immediate vicinity of the stream
crossings, quantitative habitat surveys were not conducted as part of this study. Habitat
quality and quantity is an important factor for prioritizing sites for remediation or
replacement. Therefore, habitat quality information was collected or determined, in order
of preference, from:
• Habitat surveys collected by CDFG, tribal fisheries biologists, timber company
biologists, or other reputable sources,
• County fish passage assessment reports where county- owned stream crossings are
present on the same watersheds as Caltrans- owned crossings,
• Professional judgement of biologists or local restoration groups familiar with the
watershed, or
Habitat quantity values were determined from:
• Habitat surveys collected by CDFG, tribal fisheries biologists, timber company
biologists, or other reputable sources,
• Locations of known barriers, such as dams, waterfalls, etc., or
• Topographic maps used to identify the upper limit of anadromous habitat. The
upper limit of anadromy was defined at the point where the channel exceeded an
eight percent slope for at least a 300- foot channel reach.
Specific sources or assumptions made for all habitat quality and quantity values used for
assessment or prioritization are clearly referenced whenever these values are presented or
used.
2.10 Prioritization
Prioritization is used to rank sites in order from high to low priority for remediation or
replacement to meet fish passage objectives. Prioritization begins by “ scoring” sites
based on their species diversity, extent of barrier present, flood capacity and maintenance
condition, habitat quantity and habitat quality. Prioritization rankings for all routes are
determined in the same manner so the numerical scores can be merged or combined to
rank sites on a county, watershed or other basis. These prioritization scores are not meant
30
for making the final decisions regarding fish passage remediation. Professional judgment,
opportunities created by scheduled maintenance or construction or restoration emphasis
in a particular watershed by multiple agencies or stakeholders must also factor into these
decisions. Thus, these prioritization rankings should be viewed as a first cut at developing
a remediation strategy rather than a strict order for remediation actions.
The criteria and scoring for ranking stream crossings were taken from Part IX of CDFG’s
California Salmonid Stream Habitat Restoration Manual ( Taylor and Love, 2003) with
one exception. A “ Crossing Score” is used instead of distinct scores for “ Size ( risk of
failure)” and “ Current Condition.” Taylor ( 2003) first introduced this modification in
assessment of Marin County stream crossings. Combining the “ Size “ and “ Current
Condition” scores to a “ Crossing Score” reduces the total weight given to a stream
crossing’s condition from 26% to ~ 15% of the site’s ranking score. This reduction in
weight of the size/ condition increases the weight of the species diversity and habitat
characteristics of each site; thus, preventing very small culverts with minimal habitat or
fish from being ranked too high.
Undersized crossings in poor condition have a high risk of failure and should be a
concern to road managers. However, the primary purpose of this prioritization is to
identify sites needing fish passage remediation; thus, more weight should be put on the
biological criteria to identify crossings which are serious impediments to migration and
that have significant reaches with suitable upstream habitat.
The prioritization method used for site ranking for each route assigned a score or value
for the following criteria at each crossing location. The total score was the sum of four
criteria: species diversity, extent of barrier, average value of crossing sizing and current
condition, and total habitat score. A brief description of each score ( taken from Taylor
and Love, 2003) is given here:
1. Species diversity: number of salmonid species currently or historically present in
the stream reach at the culvert location. Score: Endangered species = 4 points,
Threatened species ( coho salmon and steelhead) = 2 points, Species of Concern,
unlisted and resident salmonids = 1 point.
2. Extent of barrier: This value is determined for each species and age class of
salmonid ( adult, resident trout or 2+ age class, and juvenile). Over the range of fish
passage design flows for each fish type, assign one of the following values. Score:
0 = 80- 100% passable ( GREEN ranked sites using CDFG ranking filter and GRAY
ranked sites determined passable using FishXing); 1 = 60- 80% passable; 2 = 40-
60% passable; 3 = 20- 40% passable; 4 = less than 20% passable; 5 = 0% passable
( RED ranked sites using CDFG ranking filter and GRAY ranked sites determined
impassable using FishXing). The total extent of barrier score is the sum of the three
scores. Maximum score = 15 points.
31
3. Crossing Score: For each crossing determine the sizing ( risk of failure) and
condition scores as defined below and compute the average value. Maximum score
= 5 points.
Sizing ( risk of failure): For each culvert, assign one of the following values for the
capacity of the culvert flowing full. Score: 0 = sized to NMFS standards, passes
the 100- year flow at less than or equal to inlet height. 1 = sized for at least a 50- year
flow, low risk. 2 = sized for at least a 25- year flow, moderate risk. 3 = sized for
less than a 25- year flow, moderate to high risk of failure. 4 = sized for less than a
10- year event, high risk of failure. 5 = sized for less than a 5- year event, extreme
risk of failure.
Current condition: For each culvert, assign one of the following values. Score: 0
= good condition. 1 = fair, showing signs of wear. 3 = poor, floor rusting through,
crushed by roadbase, etc. 5 = extremely poor, floor rotted- out, severely crushed,
damaged inlets, collapsing wingwalls, slumping roadbase, etc.
4. Habitat quantity: Determine the habitat quantity above each crossing in units of
feet. Score: Starting at a 500’ minimum; 0.5 points for each 500’ length ( example:
0 points for < 500’; 1 point for 1,000’; 2 points for 2,000’; 3.5 points for 3,500’; and
so on). Maximum score = 10 points.
5. Habitat quality: For each stream, assign a “ multiplier” of quality after reviewing
available habitat information. The habitat quality score should be assigned relative to
other streams on the route.
• Score: 1.0 = Excellent- Relatively undeveloped, “ pristine” watershed conditions.
Habitat features include dense riparian zones with mix of mature native species,
frequent pools, high- quality spawning areas, cool summer water temperatures,
complex in- channel habitat, and/ or channel floodplain relatively intact. High
likelihood of no future human development. Presence of migration barrier( s) is
obviously the watershed’s limiting factor.
• 0.75 = Good- Habitat is fairly intact, but human activities have altered the
watershed with likelihood of continued activities. Habitat still includes dense
riparian zones of native species, frequent pools, spawning gravels, cool summer
water temperatures, complex in- channel habitat, and/ or channel floodplain
relatively intact. Presence of migration barrier( s) is most likely one of the
watershed’s primary limiting factor.
• 0.5 = Fair- Human activities have altered the watershed with likelihood of
continued ( or increased) activities, with apparent effects to watershed processes
and features. Habitat impacts include riparian zone present but lack of mature
conifers and/ or presence of non- native species, infrequent pools, sedimentation
evident in spawning areas ( pool tails and riffle crests), summer water
temperatures periodically exceed stressful levels for salmonids, sparse in- channel
32
complex habitat, floodplain intact or slightly modified). Presence of migration
barrier( s) may be one of the watershed’s limiting factor ( out of several factors).
• 0.25 = Poor- Human activities have drastically altered the watershed with high
likelihood of continued ( or increased) activities, with apparent effects to
watershed processes. Habitat impacts include riparian zones absent or severely
degraded, little or no pool formations, excessive sedimentation evident in
spawning areas ( pool tails and riffle crests), stressful to lethal summer water
temperatures common, lack of in- channel habitat, floodplain severely modified
with levees, riprap, and/ or residential or commercial development. Other limiting
factors within watershed are most likely of a higher priority for restoration than
remediation of migration barriers.
6. Total habitat score: Multiply # 4 by # 5 to obtain a total habitat score. A multiplier
assigned for habitat quality, weighs the final score more on quality than sheer
quantity of upstream habitat. Maximum score = 10 points.
Total Stream Crossing Score = Species Diversity Score + Extent of Barrier Score +
0.5*( Sizing Score + Current Condition Score) + Total Habitat Score
For each culvert location, the five ranking criteria were entered into a prioritization
spreadsheet and the total scores computed. The list of sites is then sorted by the “ Total
Score” in a descending order to determine an initial prioritization ranking for crossing
remediation. Further review of this ranking is always required as professional judgment
and socioeconomic, political or other factors will also influence the selection of sites for
replacement or remediation.
Several additional factors also need to be considered to develop the final site rankings.
These include:
• Current fish presence or usage – maintaining access to current fish stocks should
get higher priority than providing access to historic habitat.
• Presence, status, and location of additional barriers on the stream – sites with
additional barriers will have higher or lower priority depending on the current
efforts by other owners to remove their barriers
• Scheduled or emergency construction and maintenance – opportunities arise for
site remediation and replacement and fish passage needs to considered
• Remediation or replacement cost - available funding will influence project
feasibility
• Amount of road fill – a site’s fill volume will greatly influence the project cost
and effort needed to improve fish passage.
After considering these factors, and with input from agencies and interested stakeholders,
the prioritization list can then be divided subjectively into groups defined as “ high”,
“ medium”, or “ low” priority for remediation and planning to obtain funding or develop
designs for modification can be initiated.
33
3 RESULTS
The final result of the fish passage assessment for State Highway culverts is a prioritized
list of sites needing remediation or replacement. This prioritized site list is developed
using the methods described in Section 2. There are also some preliminary findings that
are significant because they indicate the magnitude of the problem and the potential for
fish and aquatic organism passage at stream crossings. These preliminary findings, the
first pass summary to identify potential fish passage sites and the CDFG ranking matrix
results, are presented here along with the list of sites identified as having the highest
priority for remediation.
In addition to presenting the findings of Caltrans District 1 fish passage assessment, a
comparison of Caltrans and county assessment results for Del Norte, Humboldt and
Mendocino County is also included. Many streams have multiple crossings requiring
watershed- scale assessment of barriers and cooperation between landowners to eliminate
barriers to fish passage. Identifying watersheds affected by two major road owners,
Caltrans and the counties, is a major first step to watershed- based fish passage
assessment.
3.1 Survey Summaries
The First Pass Summary identified the potential fish passage sites on State Highways in
Caltrans District 1. Crews drove the greater than 800 miles of State Highway stopping at
all culverts greater than or equal to 0.6 m ( 24 inches) in diameter to evaluate whether the
sites met the potential fish passage culvert criteria ( Section 2.1). The first pass identified
411 potential fish passage sites and, as of December 1, 2004, 312 of these sites have been
surveyed and analyzed for fish passage using the protocols outlined in Section 2 of this
report. Seventy- eight of the identified potential fish passage sites were not surveyed
because they were not believed to be streams with fish present. These sites were
confirmed in a meeting with fisheries professionals held November 4, 2004 at the NOAA
Fisheries office in Arcata, California. Twenty- one sites likely to be important to fish were
not surveyed because landowners denied access permission. The First Pass Summaries
for each State Highway are included in each Highway’s sub- report.
3.2 CDFG Ranking Matrix Results
The ranking matrix used by the California Department of Fish and Game was presented
previously ( Figure 2.8). Table 3.1 summarizes the ranking results for all the potential fish
passage sites, 186 or 60% of the surveyed sites ranked RED. A RED ranking indicates
that the site does not meet current fish passage guidelines for existing culverts. The RED
ranking does not necessarily mean that the culvert is completely impassable but that the
culvert is unlikely to allow passage for the range of swimming or leaping abilities
expected for all individuals of the target fish species. At many RED- ranked sites, strong
34
Table 3.1. CDFG ranking matrix summary for Caltrans District 1 potential fish passage stream crossings.
County/ Route
Total
Miles
Total
Culverts
Potential Fish
Passage
Culverts ( PFCs)
Red
Ranked
Crossings
Gray
Ranked
Crossings
Green
Ranked
Crossings
Number of
PFCs not
surveyed Survey Status
Del Norte 101 46 359 25 5 13 4 3 Complete. Unsurveyed sites are not fish
streams.
Del Norte 197 12 62 7 4 3 0 0 Complete
Del Norte 199 36 306 27 13 4 2 8 Complete. Unsurveyed sites are not fish
streams.
Humboldt 36 46 339 25 8 5 4 8 Complete. Unsurveyed sites are not fish
streams.
Humboldt 96 45 411 11 5 0 0 6
Second pass survey and data analysis of 5
sites east of Weitchepec completed. 2 of the
remaining sites are east of these sites and
unlikely to be fish bearing streams. The other
4 sites are on Hoopa land.
Humboldt 101 135 1304 69 34 21 2 12 Complete. Unsurveyed sites are not fish
streams.
Humboldt 169 34 214 9 5 1 0 3 Complete. Unsurveyed sites are not fish
streams.
Humboldt 254 46 359 22 12 5 3 2 Complete. Unsurveyed sites are not fish
streams.
Humboldt 299 43 396 22 17 1 0 4 Complete. Unsurveyed sites are not fish
streams.
Mendocino 1 106 761 29 14 11 4 0 Complete
Mendocino 20 44 331 16 11 3 0 2 Complete. Unsurveyed sites are not fish
streams.
Mendocino 101 107 1102 61 16 8 1 36
21 of the unsurveyed sites were determined
not to be fish streams. A Permit to Enter was
not granted for 15 sites known or very likely to
support fish. These sites were included in
prioritization using the First Pass Survey
results
Mendocino 128 51 539 63 29 23 6 5
Complete. Three of the 5 unsurveyed sites
are unlikely to have fish and the 2 remaining
sites were denied a Permit to Enter.
Mendocino 162 34 360 14 6 0 1 7 Complete. Remaining sites unlikely to be fish
bearing.
Mendocino 253 17 148 11 7 1 0 3 Complete. Remaining sites unlikely to be fish
bearing.
Totals 802 6991 411 186 99 27 99
35
individuals may be able to pass through the crossing under ideal conditions but the
majority of fish are being blocked or significantly delayed.
Thirty- two percent ( 99 sites) ranked GRAY, indicating that these sites are likely to
present difficult passage conditions under some conditions or for some of the target fish.
The GRAY- ranked sites are often those sites that can be made passable without complete
replacement, and perhaps with only minor modifications.
The remaining sites ranked GREEN ( 27 sites or 9% of sites), meaning that these sites
provide good passage conditions for all species and lifestages of fish.
3.3 Prioritization
Following the prioritization procedure described in Section 2.10, and taking into account
the recommendations of fisheries and watershed professionals at the November 4, 2004
meeting, sites were ranked by score to identify the top sites for remediation or
replacement. In some cases, a site was moved up in the ranking because of additional
information such as current restoration or barrier removal activities in the watershed;
these sites are identified by additional comments.
The current prioritization ranking for all surveyed sites in Caltrans District 1 is included
as Table B. 1 in Appendix B. Green- ranked stream crossings were not included in the
prioritization list; their characteristics and locations are listed in Table B. 2. All sites that
remain unsurveyed are described in Table B. 3. Appendix B also contains additional
tables listing the prioritization of Red and Gray- ranking sites by county and describing all
Green- ranked and unsurveyed sites in Del Norte, Humboldt and Mendocino counties.
3.3.1 Top Twenty- five Priority Sites
The top 25 priority sites ( Table 3.2) were identified through application of CDFG’s
prioritization protocol and input from fisheries and watershed professionals. Detailed
descriptions of and preliminary recommendations for each of the 25 sites are included as
Appendix C. This prioritized list should not be considered static. Stream crossings often
change gradually over time and may change drastically following major floods or in
responding to rapidly changing watershed characteristics. Opportunities for restoration
will also modify the order in which sites are remediated to take advantage of cooperative
efforts by multiple landowners. Periodic re- evaluation of fish passage sites and updating
as sites are remediated is required to maintain a current priority list that can incorporate
stream crossings into project planning efforts.
In addition to the prioritization uncertainty introduced by changing conditions, many of
the streams have not had detailed habitat surveys. When a habitat survey was not
available, the length of upstream habitat was estimated using USGS 1: 24K topographic
maps to identify the length of channel upstream before a sustained eight percent channel
36
gradient existed. These maps provide a good estimate of overall channel slope but often
fail to capture abrupt natural barriers such as small falls and rarely include man- made
barriers, such as diversions and instream alterations. The upstream habitat quantity is a
major uncertainty in the prioritization process that cannot be easily checked or corrected
given current access permission requirements.
Recognizing that project planning is often initiated at scales smaller than District wide,
the prioritization results are also presented at the county level. Tables 3.3– 5 summarize
the top 10 sites for each county in District 1. Because Mendocino County had 12 sites
ranking in the top 25 district- wide sites, all of its top ten sites are on both lists. Humboldt
County with seven of the top 25 has an additional 3 sites on its top ten list and Del Norte
County, with only six sites in the top 25 district- wide sites has 4 additional sites.
Additional combinations for prioritization ( e. g. on a State Highway or County/ State
Highway basis) are available electronically.
37
Table 3.2. Top 25 Priority Sites for Fish Passage Remediation in Caltrans District 1
RANK
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
1 Humboldt 254 4.18 Fish Creek Weott Coho, Chinook,
Steelhead 8,600 29.00 A, B
2 Mendocino 101 52.25 Ryan Creek Outlet Creek Coho, Chinook,
Steelhead 9,000 28.00 A, D
Access was denied for site survey. Culvert is a 5- ft
diameter corrugated metal pipe with outlet at stream
grade and a concrete bottom lining but slope is unknown.
Assumed some minimal adult passage for a barrier score
of 14.
3 Mendocino 101 81.46 Rattlesnake
Creek Benbow Coho, Chinook,
Steelhead 41,000 27.50 A, B
4 Del Norte 197 5.00 Sultan Creek Smith River
Plain
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
4,500 27.38 A, D
5 Mendocino 101 48.14 Upp Creek Outlet Creek Coho, Chinook,
Steelhead 7,600 27.30 A, B
6 Mendocino 101 83.99 Rattlesnake
Creek Benbow Coho, Chinook,
Steelhead 67,700 27.00 A, B
6 Mendocino 101 89.04 Cedar Creek Benbow Coho, Chinook,
Steelhead 42,200 27.00 A, B
8 Mendocino 101 52.36 Ryan Creek Outlet Creek Coho, Chinook,
Steelhead 6,800 26.90 A, D
Access was denied for site survey. Culvert is a 5- ft
diameter corrugated metal pipe with a 2.5 - 3 ft outlet
perch at low flow and a concrete bottom lining but slope is
unknown. Assumed no passage for a barrier score of 15.
Reference Codes
A – Species diversity taken from CDFG surveys or direct observations from local fisheries biologists. See Appendix B - Site Summaries for sources
B – Length of habitat taken from CDFG surveys
C – Species diversity assumed by presence in downstream confluence channel, size and slope of creek or observation upon site visit
D – Length of habitat estimated using USGS topographic maps
E – Presumed not a significant anadromous fish stream
R – Obtained species diversity and habitat information from Ross Taylor & Associates, Humboldt County Culvert Inventory and Fish Passage Evaluation ( 2000), Del Norte County
Culvert Inventory and Fish Passage Evaluation ( 2001), or Mendocino County Culvert Inventory and Fish Passage Evaluation ( 2001) reports
38
Table 3.2. Top 25 Priority Sites for Fish Passage Remediation in Caltrans District 1, cont’d.
Rank
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
9 Mendocino 1 58.78 Digger Creek Noyo River Coho, Steelhead 11,000 26.50 A, D
10 Del Norte 197 6.15 Little Mill
Creek
Smith River
Plain
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
4,900 26.45 A, D
Score increased from 23.45 to 26.45 to adjust Del Norte
rankings to match professional consensus. Little Mill
Creek has had significant restoration activity in recent
years.
11 Humboldt 299 2.97 Essex Gulch Blue Lake
Coho,
Steelhead,
Coastal
Cutthroat Trout
6,000 26.00 C, D
A county culvert currently blocks Essex Gulch
approximately 100 feet downstream of the State Highway
culvert. The county culvert is perched about 5 feet. A joint
project will be important if/ when the county culvert is
altered, as any fix to the county culvert will influence the
fish passage and hydraulics of the State Highway culvert.
12 Del Norte 101 39.78 Dominie
Creek
Smith River
Plain
Coho,
Steelhead,
Coastal
Cutthroat Trout
8,400 25.70 A, D Maintenance work is needed to repair exposed and
corroding rebar.
13 Humboldt 101 124.49 Little Lost Man
Cr. Orick
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
4,200 25.65 A, D
14 Humboldt 101 59.94 Strongs Creek Ferndale
Coho,
Steelhead,
Coastal
Cutthroat Trout
19,000 25.50 A, D
Site is likely ranked too high. Passage through this low
slope, concrete box culvert is predicted to be impeded
primarily by water depth.
Reference Codes
A – Species diversity taken from CDFG surveys or direct observations from local fisheries biologists. See Appendix B - Site Summaries for sources
B – Length of habitat taken from CDFG surveys
C – Species diversity assumed by presence in downstream confluence channel, size and slope of creek or observation upon site visit
D – Length of habitat estimated using USGS topographic maps
E – Presumed not a significant anadromous fish stream
R – Obtained species diversity and habitat information from Ross Taylor & Associates, Humboldt County Culvert Inventory and Fish Passage Evaluation ( 2000), Del Norte County
Culvert Inventory and Fish Passage Evaluation ( 2001), or Mendocino County Culvert Inventory and Fish Passage Evaluation ( 2001) reports
39
Table 3.2. Top 25 Priority Sites for Fish Passage Remediation in Caltrans District 1, cont’d.
RANK
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
15 Del Norte 199 31.31 Griffin Creek Middle Fork
Smith River
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
9,700 25.48 A, B
Score increased from 24.28 to 25.48 to adjust Del Norte
rankings to match professional consensus. Site needs in
channel work to improve rock weirs at the outlet to provide
passage. Consider fixing earlier as this stream crossing fix
is low cost and provides a good return for the effort.
16 Mendocino 101 44.51 Unnamed Trib
to Haehl Ck Outlet Creek Coho, Chinook,
Steelhead 8,600 25.30 C, D
17 Mendocino 1 54.62 Doyle Creek Big River Coho, Steelhead 12,500 25.00 A, D
17 Mendocino 1 57.81 Mitchell Creek Noyo River Coho, Steelhead 13,000 25.00 A, B
17 Del Norte 197 2.12 Peacock
Creek
Smith River
Plain
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
6,000 25.00 A, D Score increased from 21.50 to 25.00 to adjust Del Norte
rankings to match professional consensus.
20 Mendocino 1 4.64 Fish Rock
Gulch Garcia River Coho, Steelhead 2,900 24.68 A, D
Reference Codes
A – Species diversity taken from CDFG surveys or direct observations from local fisheries biologists. See Appendix B - Site Summaries for sources
B – Length of habitat taken from CDFG surveys
C – Species diversity assumed by presence in downstream confluence channel, size and slope of creek or observation upon site visit
D – Length of habitat estimated using USGS topographic maps
E – Presumed not a significant anadromous fish stream
R – Obtained species diversity and habitat information from Ross Taylor & Associates, Humboldt County Culvert Inventory and Fish Passage Evaluation ( 2000), Del Norte County
Culvert Inventory and Fish Passage Evaluation ( 2001), or Mendocino County Culvert Inventory and Fish Passage Evaluation ( 2001) reports
40
Table 3.2. Top 25 Priority Sites for Fish Passage Remediation in Caltrans District 1, cont’d.
RANK
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
21 Del Norte 101 2.22 Waukell Creek Klamath Glen
Coho,
Steelhead,
Coastal
Cutthroat Trout
5,000 24.00 A, D
The highest priority barrier on Waukell Ck is the concrete
channel ( a > 25% slope) just downstream of the stream
crossing at PM 2.22. The stream crossing should only be
addressed before the concrete channel is passable to
provide upstream passage for resident coastal cutthroat
trout into the Waukell Creek headwaters.
22 Humboldt 101 95.60 Strawberry
Creek Blue Lake
Coho,
Steelhead,
Coastal
Cutthroat Trout
18,000 24.00 A, R
Just upstream of this culvert, the stream is channelized in
a trapezoidal, concrete channel along Central Avenue
through McKinleyville. Fish access into the Strawberry
Creek watershed requires remediation of the State
Highway culvert and the concrete channel both of which
are Caltrans property.
22 Humboldt 36 9.92 Flannigan
Creek Hydesville Chinook, Coho,
Steelhead 3,800 23.90 B, C
24 Mendocino 20 30.87
Unnamed Trib
to Broaddus
Creek
Outlet Creek Coho, Chinook,
Steelhead 3,700 23.85 C, D
25 Humboldt 101 99.03 Luffenholtz
Creek Big Lagoon
Steelhead,
Coastal
Cutthroat Trout
37,000 23.50 A, R
Site is likely ranked too high. Downstream barriers, both
natural and road culverts, prevent anadromous fish
access ( Taylor, 2000). Luffenholtz Creek provides very
good resident salmonid habitat but anadromous use is
unlikely.
Reference Codes
A – Species diversity taken from CDFG surveys or direct observations from local fisheries biologists. See Appendix B - Site Summaries for sources
B – Length of habitat taken from CDFG surveys
C – Species diversity assumed by presence in downstream confluence channel, size and slope of creek or observation upon site visit
D – Length of habitat estimated using USGS topographic maps
E – Presumed not a significant anadromous fish stream
R – Obtained species diversity and habitat information from Ross Taylor & Associates, Humboldt County Culvert Inventory and Fish Passage Evaluation ( 2000), Del Norte County
Culvert Inventory and Fish Passage Evaluation ( 2001), or Mendocino County Culvert Inventory and Fish Passage Evaluation ( 2001) reports
41
Table 3.3. Top 10 Priority Sites for Fish Passage Remediation in Del Norte County. Ranks are rank within Del Norte County, not District 1.
RANK
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
1 Del Norte 197 5.00 Sultan Creek Smith River
Plain
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
4,500 27.38 A, D
2 Del Norte 197 6.15 Little Mill
Creek
Smith River
Plain
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
4,900 26.45 A, D
Score increased from 23.45 to 26.45 to adjust Del Norte
rankings to match professional consensus. Little Mill
Creek has had significant restoration activity in recent
years.
3 Del Norte 101 39.78 Dominie
Creek
Smith River
Plain
Coho,
Steelhead,
Coastal
Cutthroat Trout
8,400 25.70 A, D Maintenance work is needed to repair exposed and
corroding rebar.
4 Del Norte 199 31.31 Griffin Creek Middle Fork
Smith River
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
9,700 25.48 A, B
Score increased from 24.28 to 25.48 to adjust Del Norte
rankings to match professional consensus. Site needs in
channel work to improve rock weirs at the outlet to provide
passage. Consider fixing earlier as this stream crossing fix
is low cost and provides a good return for the effort.
5 Del Norte 197 2.12 Peacock
Creek
Smith River
Plain
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
6,000 25.00 A, D Score increased from 21.50 to 25.00 to adjust Del Norte
rankings to match professional consensus.
6 Del Norte 101 2.22 Waukell Creek Klamath Glen
Coho,
Steelhead,
Coastal
Cutthroat Trout
5,000 24.00 A, D
The highest priority barrier on Waukell Ck is the concrete
channel ( a > 25% slope) just downstream of the stream
crossing at PM 2.22. The stream crossing should only be
addressed before the concrete channel is passable to
provide upstream passage for resident coastal cutthroat
trout into the Waukell Creek headwaters.
7 Del Norte 197 0.36 Rock Creek Smith River
Plain
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
600 23.30 A, D
42
Table 3.3. Top 10 Priority Sites for Fish Passage Remediation in Del Norte County, cont’d. Ranks are rank within Del Norte County, not District 1.
RANK
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
8 Del Norte 199 2.56 Clarks Creek Lower Smith
River
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
6,100 27.10 A, B, R
Clarks Creek has the most pristine habitat of any of the
Del Norte County streams and is a high priority for fish
access. The crossing has baffles and is predicted to pass
adult salmonids but not resident or juvenile salmoinds.
9 Del Norte 101 35.56 Tryon Creek Lower Smith
River
Coho,
Steelhead,
Coastal
Cutthroat Trout
1,400 22.20 A, D
Tryon Creek is likely ranked too high. Habitat is poor and
tide gate barriers downstream limit access to Tryon
Creek.
10 Del Norte 101 31.75
Brush or Bush
Creek ( local
name)
Lower Smith
River
Coho,
Steelhead,
Coastal
Cutthroat Trout
1,800 21.90 A, R
Reference Codes
A – Species diversity taken from CDFG surveys or direct observations from local fisheries biologists. See Appendix B - Site Summaries for sources
B – Length of habitat taken from CDFG surveys
C – Species diversity assumed by presence in downstream confluence channel, size and slope of creek or observation upon site visit
D – Length of habitat estimated using USGS topographic maps
E – Presumed not a significant anadromous fish stream
R – Obtained species diversity and habitat information from Ross Taylor & Associates, Humboldt County Culvert Inventory and Fish Passage Evaluation ( 2000), Del Norte County
Culvert Inventory and Fish Passage Evaluation ( 2001), or Mendocino County Culvert Inventory and Fish Passage Evaluation ( 2001) reports
43
Table 3.4. Top 10 Priority Sites for Fish Passage Remediation in Humboldt County. Ranks are rank within Humboldt County, not District 1.
RANK
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
1 Humboldt 254 4.18 Fish Creek Weott Coho, Chinook,
Steelhead 8,600 29.00 A, B
2 Humboldt 299 2.97 Essex Gulch Blue Lake
Coho,
Steelhead,
Coastal
Cutthroat Trout
6,000 26.00 C, D
A county culvert currently blocks Essex Gulch
approximately 100 feet downstream of the State Highway
culvert. The county culvert is perched about 5 feet. A joint
project will be important if/ when the county culvert is
altered, as any fix to the county culvert will influence the
fish passage and hydraulics of the State Highway culvert.
3 Humboldt 101 124.49 Little Lost Man
Cr. Orick
Coho, Chinook,
Steelhead,
Coastal
Cutthroat Trout
4,200 25.65 A, D
4 Humboldt 101 59.94 Strongs Creek Ferndale
Coho,
Steelhead,
Coastal
Cutthroat Trout
19,000 25.50 A, D
5 Humboldt 101 95.60 Strawberry
Creek Blue Lake
Coho,
Steelhead,
Coastal
Cutthroat Trout
18,000 24.00 A, R
Just upstream of this culvert, the stream is channelized in
a trapezoidal, concrete channel along Central Avenue
through McKinleyville. Fish access into the Strawberry
Creek watershed requires remediation of the State
Highway culvert and the concrete channel both of which
are Caltrans property.
6 Humboldt 36 9.92 Flannigan
Creek Hydesville Chinook, Coho,
Steelhead 3,800 23.90 B, C
7 Humboldt 101 99.03 Luffenholtz
Creek Big Lagoon
Steelhead,
Coastal
Cutthroat Trout
37,000 23.50 A, R
Site is likely ranked too high. Downstream barriers, both
natural and road culverts, prevent anadromous fish
access ( Taylor, 2000). Luffenholtz Creek provides very
good resident salmonid habitat but anadromous use is
unlikely.
8 Humboldt 254 40.83 Chadd Creek Scotia Coho, Chinook,
Steelhead 4,000 22.50 A, B
9 Humboldt 101 40.12 Chadd Creek Scotia Chinook, Coho,
Steelhead 900 22.45 A, B
44
Table 3.4. Top 10 Priority Sites for Fish Passage Remediation in Humboldt County, cont’d. Ranks are rank within Humboldt County, not District 1.
RANK
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
10 Humboldt 96 36.88 Crawford
Creek Orleans Steelhead 7,000 22.25 K1, K2
11 Humboldt 36 5.18 Wilson Creek
( sign) Hydesville Chinook, Coho,
Steelhead 5,400 22.20 A, D
12 Humboldt 96 36.35 Ullathorne
Creek Orleans Steelhead 6,000 21.50 K1, K2
Reference Codes
A – Species diversity taken from CDFG surveys or direct observations from local fisheries biologists. See Appendix B - Site Summaries for sources
B – Length of habitat taken from CDFG surveys
C – Species diversity assumed by presence in downstream confluence channel, size and slope of creek or observation upon site visit
D – Length of habitat estimated using USGS topographic maps
E – Presumed not a significant anadromous fish stream
R – Obtained species diversity and habitat information from Ross Taylor & Associates, Humboldt County Culvert Inventory and Fish Passage Evaluation ( 2000), Del Norte County
Culvert Inventory and Fish Passage Evaluation ( 2001), or Mendocino County Culvert Inventory and Fish Passage Evaluation ( 2001) reports
K1 – Species diversity from Karuk Tribal Fisheries
K2 – Habitat information from Karuk Tribal Fisheries
45
Table 3.5. Top 10 Priority Sites for Fish Passage Remediation in Mendocino County. Ranks are rank within Mendocino County, not District 1.
RANK
County Route
Post
Mile Stream Name
Calwater Unit
Hydrologic
Subarea
( HSA)
Presumed
Species
Diversity
Length of
Upstream
Habitat
TOTAL
SCORE References Comments
1 Mendocino 101 52.25 Ryan Creek Outlet Creek Coho, Chinook,
Steelhead 9,000 28.00 A, D
Access was denied for site survey. Culvert is a 5- ft
diameter corrugated metal pipe with outlet at stream
grade and a concrete bottom lining but slope is unknown.
Assumed some minimal adult passage for a barrier score
of 14.
2 Mendocino 101 81.46 Rattlesnake
Creek Benbow Coho, Chinook,
Steelhead 41,000 27.50 A, B
3 Mendocino 101 48.14 Upp Creek Outlet Creek Coho, Chinook,
Steelhead 7,600 27.30 A, B
4 Mendocino 101 83.99 Rattlesnake
Creek Benbow Coho, Chinook,
Steelhead 67,700 27.00 A, B
4 Mendocino 101 89.04 Cedar Creek Benbow Coho, Chinook,
Steelhead 42,200 27.00 A, B
6 Mendocino 101 52.36 Ryan Creek Outlet Creek Coho, Chinook,
Steelhead 6,800 26.90 A, D
Access was denied for site survey. Culvert is a 5- ft
diameter corrugated metal pipe with a 2.5 - 3 ft outlet
perch at low flow and a concrete bottom lining but slope is
unknown. Assumed no passage for a barrier score of 15.
7 Mendocino 1 58.78 Digger Creek Noyo River Coho, Steelhead 11,000 26.50 A, D
8 Mendocino 101 44.51 Unnamed Trib
to Haehl Ck Outlet Creek Coho, Chinook,
Steelhead 8,600 25.30 C, D
9 Mendocino 1 54.62 Doyle Creek Big River Coho, Steelhead 12,500 25.00 A, D
10 Mendocino 1 57.81 Mitchell Creek Noyo River Coho, Steelhead 13,000 25.00 A, B
Reference Codes
A – Species diversity taken from CDFG surveys or direct observations from local fisheries biologists. See Appendix B - Site Summaries for sources
B – Length of habitat taken from CDFG surveys
C – Species diversity assumed by presence in downstream confluence channel, size and slope of creek or observation upon site visit
D – Length of habitat estimated using USGS topographic maps
46
3.4 Comparison of Caltrans and County Prioritizations
In Caltrans District 1, the counties ( Del Norte, Humboldt, and Mendocino) completed
initial fish passage assessment of their stream crossings in 2000 ( Humboldt County) and
2001 ( Del Norte and coastal Mendocino County). Tables 3.6– 8 describe stream crossing
sites in watersheds where both County and Caltrans stream crossings exist. Del Norte
County has significant overlap of watersheds with stream crossings of both County roads
and State Highways so only streams with County sites ranking in the top 15 that also
have State Highway crossings are included. In Del Norte County, the County’s top five
sites have been fixed but only two of these streams have Caltrans crossings that need
remediation ( Clarks Creek, DN199 PM 2.56 and Peacock Creek, DN 197 PM 2.12). The
remaining sites are lower priority for remediation, generally due to limited habitat or fish
presence.
Humboldt and Mendocino County’s priority stream crossings had little overlap with the
Caltrans sites so all sites are included in those comparison tables. Essex Gulch
( HUM299, PM 2.97) and Strawberry Creek ( HUM101, PM 95.60) are the highest-ranking
sites with both County and Caltrans crossings in Humboldt County. The County
and Caltrans crossings at Essex Gulch are adjacent with the County crossing just
downstream of the State Highway crossing and currently creating a total barrier to fish
passage due to an excessive outlet perch. Any modifications to either crossing would
require cooperation between Humboldt County and Caltrans. At Strawberry Creek, the
Caltrans crossing and its associated upstream channel are the most downstream barriers
in the system.
In Mendocino County, the two Ryan Creek crossings on MEN101 ( PM 52.25 and 52.36)
are 500 feet upstream from a County crossing that is scheduled for replacement in 2005.
Numerous anadromous salmonid species ( T. Weseloh, Pers. Comm., 2004) have been
observed blocked by the County culvert. When the County crossing is replaced, the
MEN101 crossings will be the most downstream barriers. Because Ryan Creek splits into
two forks just upstream of the County culvert, each of the Caltrans culverts blocks a
significant length of upstream habitat to a fork of Ryan Creek.
47
Table 3.6. Comparison of Del Norte County Stream Crossings Prioritization to Caltrans.
County Stream
Crossing
Priority Rank
County Stream
Crossing Status of County Crossing1
Location of Caltrans Stream
Crossing
Passage Status of Caltrans
stream crossing
Caltrans
Stream
Crossing
Priority Rank2
1 Jordan Creek at
Parkway Dr
Crossing replaced with an open bottom,
CON/ SPAN arch in 2000.
DN101 crossing at PM 30.31 is
1500 feet downstream
The DN101 crossing of the
mainstem Jordan Creek at PM
30.31 is a Green- ranked site
that presents no barrier or
hindrance to fish passage.
Does not need
remediation. Not
on priority list.
2 Clark’s Creek at
Walker Rd Crossing replaced with a bridge in 2002. DN199 crossing at PM 2.56 is
1400 ft upstream
The DN199 crossing is modified
with baffles through one barrel
so allows some adult passage.
Site ranked high for remediation
because of excellent habitat in
Clark’s Creek.
8
3 Peacock Creek at Tan
Oak Dr
Crossing modified for fish passage by
addition of fishway at the outlet in 2003
DN197 crossing at PM 2.12 is
1000 ft upstream
The DN197 crossing allows
significant adult passage.
Priority ranking increased
because of significant
watershed restoration efforts.
5
4 Jordan Creek at Elk
Valley Rd
Crossing replaced with an open bottom,
CON/ SPAN arch in 2003.
DN101 crossing at PM 30.31 is
4500 feet downstream
The DN101 crossing of the
mainstem Jordan Creek at PM
30.31 is a Green- ranked site
that presents no barrier or
hindrance to fish passage.
Does not need
remediation. Not
on priority list.
5 Mynot Creek at Mynot
Creek Rd
Crossing replaced an open bottom,
CON/ SPAN arch in 2003.
Highway crossing at PM 8.14 is
700 ft downstream
Highway crossing is a natural
bottom bridge and presents no
barrier to fish passage.
Does not need
remediation. Not
on priority list.
6
Yonker’s Creek at
Wonderstump
Rd
Submitted for treatment but DN101 crossing at PM 32.24 is
1600 ft upstream
The DN101 crossing provides
significant passage for all
species and lifestages.
42
1 – Status of County road culverts taken from DEL NORTE COUNTY CULVERT INVENTORY AND FISH PASSAGE EVALUATION ( Taylor, 2001) or personal communication with
County personnel.
2 – This Caltrans priority rank considers only the State Highway fish passage sites in Del Norte County only, not all of District 1.
48
Table 3.6. Comparison of Del Norte County Stream Crossings Prioritization to Caltrans, cont’d.
County Stream
Crossing
Priority Rank County Stream Crossing Status of County Crossing1
Location of Caltrans Stream
Crossing
Passage Status of Caltrans
stream crossing
Caltrans
Stream
Crossing
Priority Rank2
7 Nune’s Creek at Elk Valley
Rd
Moderate priority due to limited
spawning and rearing habitat
upstream of crossing. Coho
salmon adults are able to pass on
most flows.
DN101 crossing at PM 26.15 is 2.9
miles downstream right at the
mouth of Elk Creek.
The DN101 Elk Creek crossing
is a backwatered, low slope box
culvert that does not block or
hinder fish passage.
Does not need
remediation. Not
on priority list.
8 Lopez Creek at Oceanview
Dr
Moderate- priority. A total barrier to
all species and lifestages but there
is limited upstream habitat
( 1,700’). Downstream habitat is of
margin quality too.
DN101 crossing at PM 43.75 is
1100 ft downstream
The DN101 crossing is
predicted to be a barrier due to
water depth. May allow some
passage.
16
9 Ritmer Creek at Oceanview
Rd
Moderate- priority. A total barrier to
all species and lifestages but there
is limited upstream habitat.
Downstream habitat is of marginal
quality too.
DN101 crossing at PM 41.41 is
2800 ft downstream
The DN101 crossing is
predicted to be a complete
barrier due to leap height and
water depth.
19
11 Elk Creek tributary at Elk
Valley Rd
Moderate/ low- priority due to:
limited upstream habitat and
partial passage of adults and older
juveniles.
DN101 crossing at PM 26.15 is 2.5
miles downstream right at the
mouth of Elk Creek.
The Elk Creek crossing is a
backwatered, low slope box
culvert that does not block or
hinder fish passage.
Does not need
remediation. Not
on priority list.
12
Jordan Creek tributary # 3 at
Campground Loop in Keller
Park
Moderate/ low- priority due to:
limited upstream habitat ( 900’) and
presence of numerous spawning
cutthroat upstream of crossing.
DN101 crossing at PM 31.11 is
500 feet upstream
13 Jordan Creek tributary # 2 at
Cunningham Lane
Moderate/ low- priority due to:
limited amount of upstream
habitat, and partial passage of
adults and juveniles through
current crossing.
DN101 crossing at PM 31.11 is
1300 feet upstream
The DN101 crossing is
predicted to be a barrier due to
water depth. May allow some
passage.
21
15 Brush Creek at Wonderstump
Rd
Moderate/ low- priority because
current crossing allows adult
migration on most flows and partial
juvenile migration.
DN 101 crossing at PM 31.75 is
3000 feet upstream
Outlet is backwatered but
culvert is predicted to be a
complete barrier due to water
depth and velocity. A hydraulic
jump is predicted at fish
passage design flows.
10
1 – Status of County road culverts taken from DEL NORTE COUNTY CULVERT INVENTORY AND FISH PASSAGE EVALUATION ( Taylor, 2001) or personal communication with
County personnel.
2 – This Caltrans priority rank considers only the State Highway fish passage sites in Del Norte County only, not all of District 1.
49
Table 3.7 Comparison of Humboldt County Stream Crossings Prioritization to Caltrans.
County Stream
Crossing
Priority Rank
County Stream
Crossing Status of County Crossing1
Location of Caltrans Stream
Crossing
Passage Status of Caltrans
stream crossing
Caltrans
Stream
Crossing
Priority Rank2
Not yet
determined Essex Gulch
Just assessed in the Humboldt County
cleanup. Will rank high ( pers. comm. R.
Taylor, Nov. 2004)
HUM299 crossing at PM 2.97 is
100 ft upstream
Essex Gulch is currently blocked
by a county culvert approximately
100 feet downstream of the State
Highway culvert. The county
culvert is perched about 5 feet. A
joint project will be important
if/ when the county culvert is
altered as any fix to the county
culvert will influence the fish
passage and hydraulics of the
State Highway culvert.
2
22 Rocky Gulch at Old
Arcata Rd
Historic coho, steelhead and cutthroat
stream. Dropped in priority due to decline
in habitat condition from past and current
landuse practices
HUM101 crossing at PM 83.61
is 2500 feet downstream
The HUM101 crossing is a Green-ranked
site that presents no barrier
or hindrance to fish passage. Just
downstream of the HUM101
crossing is a railroad crossing and
tidegates that limit passage at the
mouth of Rocky Gulch.
Does not need
remediation. Not
on priority list.
26 Strawberry Creek at
Dows Prairie Rd
Dropped in priority because this crossing
is located upstream of two other potential
barriers.
HUM101 crossing at PM 95.60
is 1.3 miles downstream
32 Strawberry Creek at
Central Avenue
Dropped in priority because of probable
passage problem at Highway 101
HUM101 crossing at PM 95.60
is 800 feet downstream
Just upstream of this culvert, the
stream is channelized in a steep
trapezoidal, concrete channel
along Central Avenue through
McKinleyville. Fish access into the
Strawberry Creek watershed
requires remediation of both the
State Highway culvert and the
concrete channel.
6
28 Luffenholtz Creek at
Westhaven Dr
This culvert is a barrier to resident rainbow
and cutthroat trout located in middle of
long fish- bearing stream reach. Treatment
with baffles, weirs, and outlet beam would
be relatively inexpensive.
HUM101 crossing at PM 99.03
is 1200 feet downstream
33 Luffenholtz Creek at
Trinidad Scenic Dr
Dropped in priority because a steep set of
natural falls below culvert ( just above
beach) inhibits access to culvert outlet.
HUM101 crossing at PM 99.03
is 500 feet upstream
The HUM101 culvert is a total
barrier because of a steep slope, a
leap over an outlet weir and a
cascade over boulders just
downstream of the culvert outlet.
Natural barriers at the creek outlet
likely prevent anadromous adult
access.
8
1 – Status and descriptions of County road culverts taken from HUMBOLDT COUNTY CULVERT INVENTORY AND FISH PASSAGE EVALUATION ( Taylor, 2000) or personal
communication with County personnel.
2 – This Caltrans priority rank considers only the State Highway fish passage sites in Humboldt County only, not all of District 1.
50
Table 3.7. Comparison of Humboldt County Stream Crossings Prioritization to Caltrans, cont’d.
County Stream
Crossing
Priority Rank
County Stream
Crossing Status of County Crossing1
Location of Caltrans Stream
Crossing
Passage Status of Caltrans
stream crossing
Caltrans
Stream
Crossing
Priority Rank2
30 Widow White Creek at
Murray Rd Some work to improve passage in 2001 HUM101 crossing at PM 93.27
is 1700 feet downstream
31 Widow White Creek at
McKinleyville Rd Some work to improve passage in 2001 HUM101 crossing at PM 93.27
is 3200 feet downstream
The HUM101 crossing is modified
with baffles and weirs and is
predicted to provide some
passage for adult anadromous
salmonids. The elevation between
weirs presents a leap barrier to
resident and juvenile salmonids.
24
41 Mill Creek at Central
Avenue
Culvert set at grade, not a barrier. Located
just upstream of natural barrier to
anadromous fish ( 20 ft waterfall)
HUM101 crossing at PM 90.83
is 2900 feet downstream
45 Mill Creek at Turner
Road
Dropped because of natural barrier of 20’
high falls 200’ upstream. Between Turner
Road and Highway 101 there is
approximately 3,900’ of fair/ good
anadromous habitat
HUM101 crossing at PM 90.83
is 2100 feet downstream
The HUM101 crossing provides
good passage conditions to adult
anadromous and resident
salmonids and some passage to
juvenile salmonids so ranks very
low on the prioritization list.
92
1 – Status and descriptions of County road culverts taken from HUMBOLDT COUNTY CULVERT