Rocky Mountain Research Station
July 2000
FishXing 2.0
Software and Learning System for
the Analysis of Fish Migration
Through Culverts
by Michael J. Furniss, Susan Firor, and Michael Love
Culverted road-stream crossings sometimes
function as upstream migration barriers to
fish. Culverts can block migration of
resident and anadromous fish due to
excessive water velocities during high flows,
inadequate water depth during low flows, or
excessive drops at the outlet.
Thousands of culverts are currently installed
in fish-bearing streams around the world,
many of which are partial or total barriers to
fish migration. The impact of migration
barriers can be devastating to fish, and the
cost of retrofitting or replacing existing
culverts can be high. In many areas, effective
fisheries conservation requires that new
culverts be designed, built, and maintained
to pass fish; and that the fish-passing
performance of existing culverts be assessed,
and remediation planned and implemented.
The determination of fish passage is
complex, requiring a broad knowledge of
hydraulic engineering, fisheries biology,
stream channel geomorphology, and
hydrology. Accurate assessments require the
rigorous, concurrent, and interactive
application of these disciplines.
Thorough analysis of culvert hydraulics
relative to fish swimming and jumping
abilities, across the range of fish migration
flows can be difficult and time-consuming, but
lends itself to computer applications
assistance. A software application for
Windows, called FishXing (pronounced “fish
crossing”) has been developed by the Six
Rivers National Forest Watershed Interactions
Team. Principal sponsors include: the Stream
Systems Technology Center, Rocky Mountain
Research Station; Forest Service Engineering,
San Dimas Technology and Development
Center; the Federal Highways Administration;
and Humboldt State University.
The software helps to integrate the specific
biology, hydrology, and hydraulics
components of fish passage problems into a
single model that enables the comparison of
fish swimming capabilities to culvert
hydraulics across a range of streamflows.
Program
design
emphasizes
the
interdisciplinary nature of the problem,
incorporating the essential considerations from
fisheries biology, hydrology, fluvial
STREAM NOTES is produced
quarterly by the Stream Systems
Technology Center, Rocky
Mountain Research Station,
Fort Collins, Colorado.
Larry Schmidt, Program Manager
The PRIMARY AIM is to exchange
technical ideas and transfer
technology among scientists
working with wildland stream
systems.
CONTRIBUTIONS are voluntary
and will be accepted at any time.
They should be typewritten, singlespaced, and limited to two pages.
Graphics and tables are
encouraged.
E-Mail: jpotyondy@ fs.fed.us
Ideas and opinions expressed are
not necessarily Forest Service
policy. Citations, reviews, and use
of trade names does not constitute
endorsement by the USDA Forest
Service.
CORRESPONDENCE:
E-Mail: pswilliams01@ fs.fed.us
Phone: (970) 295-5983
FAX: (970) 295-5988
Web Site: www.stream.fs.fed.us
IN THIS ISSUE
• FishXing Software
and Learning
System
• HydrologicallyConnected Roads
• Riparian
Management in
Eastern U.S.
Forests
geomorphology, culvert and open-channel hydraulics,
and engineering. The program is designed to be easy
to use but not to obscure the complexity of the problem
or to substitute for sound professional judgment and
design.
FishXing can be used to assess existing streamcrossings. It identifies passage limitations at each site
for particular fish species and life stages, and aids in
ranking sites for remediation based on the range of
passable flows. It can also be used in designing new
stream-crossings for fish passage, enabling quick
comparisons of different design options.
Model Outputs:
The model produces two types of hydraulic analysis:
water surface profiles in the culvert (Figures 2 and 3),
and uniform flow results (where no backwater effects
are present); and outlet leap conditions (Figure 4).
The water surface profile output generates water surface
profiles at three selected flows, estimates inlet
contraction velocities, calculates average water
velocities throughout the culvert; predicts the total time
fish will spend swimming at prolonged and burst
speeds, and identifies predicted passage problems.
Culvert hydraulics, though not mathematically trivial,
are well understood and model output closely matches
reality. Watershed hydrology is often difficult to
quantify accurately due to lack of stream gauging data
and the large error associated with flow estimation at
small, ungaged streams. Behavior and swimming
capabilities of fish vary between species, life stage,
and individuals, and are not known or well understood
for many fishes. Numerous decisions based on good
judgment and the best available information must be
made for each evaluated crossing. Many of the difficult
input decisions are linked to on-line help as well as
available literature on the subject.
The uniform flow result output assumes uniform flow
conditions (no backwater effects). It identifies depth
and velocity barriers throughout the design flow range,
calculates the required leap velocity to successfully enter
the culvert, and identifies leap barriers.
Basic Model Inputs: (Figure 1)
Included with FishXing 2.0 on CD-ROM is a
multimedia ‘learning system’ that provides materials
for learning about this topic. The CD includes, in
addition to the software, audio-visual lectures about
fish passage assessment and use of the software, a
series of videos of fish passage situations, a photo
library, a virtual-reality culvert assessment site,
website links, and extensive references on the subject.
Fisheries Inputs:
Fish species; age class; length; swimming speeds—
burst and prolonged, and time to exhaustion; upper
and lower design flows.
Conclusion
Fish passage analysis is complex and
interdisciplinary. Model inputs and proper
interpretation of outputs requires firm grounding in
the relevant disciplines. FishXing cannot substitute
for expertise; it can only aid experts in the analysis.
Hydraulic Inputs:
Culvert Types: Circular, box, pipe-arch, open-bottom
arch.
Installation: At grade or embedded, or at user-defined
bed depth and roughness.
Tailwater Options: constant tailwater; user-defined
tailwater rating curve; or channel cross-section analysis.
FishXing 2.0, including the help files (but not the
multimedia presentations), can be downloaded from
the STREAM website: www.stream.fs.fed.us/
fishxing. A CD-ROM version of FishXing can be
requested from the USDA-Forest Service, San Dimas
Technology and Development Center, 444 East
Bonita Ave., San Dimas, CA 91773; Phone: (909)
599-1267; or e-mail Jeffry Moll at jmoll@fs.fed.us.
Figure 1.
Primary data
input screen.
Fish inputs are
on the left,
hydrology
inputs on the
bottom, and
culvert inputs
on the right.
Figure 2.
Water
surface
profile
results.
Figure 3. Example
water surface
profile graph. Note
that headwater,
tailwater, actual
water level, critical
depth, and normal
depth are given. A
backwater effect is
evident at about 20
feet into the
culvert.
Minimum Leap Velocity vs. Discharge
16.0
Leap Velocity (ft/s)
15.5
15.0
14.5
Low Passage Flow
High Passage Flow
Passable Leap Velocity
Excessive Leap Velocity
14.0
13.5
Max. Leap Velocity = 13.9 ft/s
13.0
0
5
10
15
20
25
30
35
40
Discharge (cfs)
Figure 4. Leaping calculations for perched outlets. FishXing calculates the minimum exit velocity, V
leapmin
for a successful attempt, and determines if Vleapmin is within the leaping ability of the design fish.
Mike Furniss is a hydrologist on assignment with the Stream Systems Technology Center, Rocky
Mountain Research Station, Fort Collins, CO. Mike is stationed on the Six Rivers National Forest,
Eureka, CA; (707) 441-3516; mfurniss@fs.fed.us.
Susan Firor and Michael Love are environmental engineers with Humboldt State University,
Institute for River Ecosystems, Arcata, CA.
Hydrologically-Connected Roads:
An Indicator of the Influence of Roads
on Chronic Sedimentation, Surface Water Hydrology,
and Exposure to Toxic Chemicals
by Michael J. Furniss, Sam A. Flanagan, and Bryan McFadin
To assess the potential for roads to affect water
quality and aquatic habitats, a simple indicator—
the amount of road hydrologically connected to
the stream network—is useful to indicate the
potential for several important adverse effects:
·
Delivery of road-derived sediments to streams
·
Hydrologic changes associated with
subsurface flow interception, concentration,
and diversion; increased drainage density; and
extension of the stream network
·
The potential for road-associated spills and
chemicals applied to roads to enter streams.
This indicator can help to distinguish between
roads that have the potential for these effects—
those that are connected to streams—and roads that
do not have these effects or potential—
unconnected roads.
Background
A study conducted in the western Cascades of
Oregon (Wemple et al., 1996), detailed the
mechanisms whereby inboard ditches on roads
extend the stream network, change runoff timing,
and increase peak flows. They found that 57% of
roads segments studied were linked to surface flow
paths. Primary linkages were ditches draining to
road-stream crossings and ditches draining to
gullies below cross-drains. A study of cross-drains
in Idaho (Haupt, 1959), used a regression equation
to relate road and slope characteristics to down
slope sediment movement. Haupt found sediment
obstructions below cross-drains and cross-drain
spacing intervals were the most important factors
in predicting sediment travel distances below
cross-drains. The study also noted that where road
drainage points were a sufficient distance from
streams, the drainage discharge re-infiltrated and did
not contribute sediment to streams. Piehl et al.
(1988) found that 38% of 515 cross-drains sampled
in the coast range of Oregon had gullies below their
outlet. Outlet erosion increased with increased ditch
length. Bilby et al (1989) reported that 34% of ditch
drainage points examined drained directly into
streams. They noted that the most effective method
of preventing road sediment from reaching streams
is to drain ditches onto the forest floor where it can
infiltrate before reaching a stream.
What is the hydrologic connectivity of roads?
Roads frequently generate overland flow from
relatively impermeable running surfaces and
cutslopes. In addition, the interception of interflow
at cutslopes can generate substantial amounts of
runoff, converting subsurface flows to surface flows.
Where these surface flows are continuous between
roads and streams, such as where inboard ditches
convey road runoff to stream channels, the road
generating or receiving the runoff is considered
“hydrologically connected” to the stream network.
In other words, a hydrologically-connected road
becomes part of the stream network. Wherever a
hydrologic connection exists, accelerated runoff,
sediments, and road-associated chemicals such as
spills or oils generated on the road surface and
cutslope have a direct route to the natural channel
network and surface waters.
We propose that this indicator be referred to as:
Hydrologically-Connected Road. Equivalent terms
include: “hydrologic integration of roads and
streams,” “stream-connected road,” or “stream
network extension by roads.”
A working definition of HydrologicallyConnected Road, is:
“Any road segment that, during a ‘design’ runoff
event, has a continuous surface flow path
between any part of the road prism and a natural
stream channel.”
Hydrologic connectivity will tend to increase with
increasing intensity and duration of precipitation
or snowmelt, and with increasing antecedent soil
moisture content. A suitable “design” runoff event
for many purposes might be the 1-year, 6-hour
storm, with antecedent moisture conditions
corresponding to the wettest month of the year, or
similar expression of precipitation depth, statistical
frequency, duration, and antecedent soil moisture
status.
The indicator may be expressed as the length or
proportion of road connected, or length or
proportion of road network in an analysis area or
reporting unit (such as a watershed) that is
connected. In addition, estimates can be made of
the amount or proportion of road than can be
“disconnected” through road improvements such
as increased cross drainage.
Water, sediment, and chemical runoff generated on
the road prism can enter the natural stream channel
network in a variety of ways (Figure 1):
·
Inboard ditches delivering runoff to a stream at
a road-stream crossing
·
Inboard ditches delivering runoff to a cross
drain (culvert, dip, waterbar, etc.) where
sufficient discharge is available to create a gully
or sediment plume that extends to a stream
channel
·
Other cross-drainage features, such as waterbars
or dips, that discharge sufficient water to create
a gully and/or sediment plume that extends to a
stream channel
·
Roads sufficiently close to streams so that the
fillslope encroaches on the stream, such as at
road-stream crossings
·
Landslide scars on the road-fill that expose
bedrock and create a surface flow path to an
adjacent channel.
A specific road segment is either hydrologically
connected or not. Partial connection can be
conceived of, but is not needed for most applications.
What can be done about it?
Road treatments to “disconnect” roads from
streams—to reduce the amount of HydrologicallyConnected-Road—are usually simple, inexpensive,
and effective in reducing road effects and risks to
water quality and aquatic habitats. Decreasing cross
drain spacing, treatments to retard flows and sediment
at cross-drain outlets, or road surface outsloping are
the most common techniques for reducing or
eliminating hydrologic connectivity. Not all road
segments can be disconnected, and specific solutions
require site-specific engineering. Accomplishments
can be measured both as the length and proportion
of road disconnected, and the associated decrease in
drainage density. Erosional yields can be estimated
for the disconnected road segment and reductions in
delivered sediment volumes quantified.
Additional discussion of this topic and methods of
assessment can be found in Flanagan et al. (1999),
and in the recently released Forest Service Roads
Analysis Guide (USDA 1999). Readers can link to
the Water-Road Interaction Technology Series
documents from the STREAM Web page
(www.stream.fs.fed.us); and Forest Service roads
analysis at: (www.fs.fed.us/news/roads/DOCSroadanalysis.shtml) to download documents.
References
Bilby, R.E.; Sullivan, K.; Duncan, S.H. 1989.
The generation and fate of road-surface
sediment in forested watersheds in
southwestern Washington. Forest Science 35:
453-468.
Flanagan, S.A.; Furniss, M.J.; Ledwith, T.; Ory,
J.; Thiesen, S.; Love, M.; Moore, K. 1998.
Methods for inventory and environmental
risk assessment of road drainage crossings.
Water/Road Interaction Technology Series.
No. 9877 1809-SDTDC. San Dimas
CA:USDA, Forest Service, Technology and
Development Program. 56 p.
Figure 1. Sketch showing ways that roads can be connected to streams. Inboard ditches, gullied cross-drain
discharges, sediment plumes below cross-drain discharges, and road-stream crossings create connected surface
flowpaths between roads and natural stream networks. Disconnecting roads from streams involves limiting the
concentration of surface discharge and using permeable soils on the forest floor and road fill slopes to infiltrate
runoff and convert it to subsurface flow before it can reach a stream.
Haupt, H.F. 1959. Road and slope characteristics
affecting sediment movement from logging
roads, J. Forestry; 57(5), 329-339.
Piehl, B.T.; Beschta, R.L.; Pyles, M.R. 1988.
Ditch-relief culverts and low-volume forest
roads in the Oregon Coast Range. Northwest
Science 62(3): 91-98.
U.S. Department of Agriculture, Forest Service.
1999. Roads Analysis: informing decisions
about managing the national forest
transportation system. Miscellaneous Report
FS-643. Washington, DC: U.S. Dept. of
Agriculture Forest Service. 222 p.
Wemple, B.C; Jones, J.; Grant, G. 1996. Channel
network extension by logging roads in two
basins, western Cascades, Oregon. Water
Resources Bulletin 32(6): 1195-1207.
Mike Furniss is a hydrologist on assignment
with the Stream Systems Technology Center,
Rocky Mountain Research Station, Fort
Collins, CO. Mike is stationed on the Six
Rivers National Forest, Eureka, CA; (707)
441-3516; mfurniss@fs.fed.us.
Sam A. Flanagan was a geologist on the Six
Rivers National Forest. He is presently with
the National Marine Fisheries Service,
Arcata, CA.
Bryan McFadin was a hydrologist on the
Six Rivers National Forest He is presently
with the California North Coast Regional
Water Quality Control Board, Santa Rosa,
CA.
STREAM
NOTES
STREAM SYSTEMS TECHNOLOGY CENTER
USDA Forest Service
Rocky Mountain Research Station
2150 Centre Ave., Bldg A, Suite 368
Fort Collins, CO 80526-1891
July 2000
O F F IC IAL B US IN E S S
P e n alty f o r P rivate U s e $ 3 00
IN THIS ISSUE
• FishXing Software
and Learning
System
• HydrologicallyConnected Roads
• Riparian
Management in
Eastern U.S.
Forests
www.stream.fs.fed.us
Riparian Management in Forests of the
Eastern Continental United States
by Elon Verry, James Hornbeck, and Andrews Dolloff
A Forest Service sponored conference about the management of forested
riparian areas in the continental eastern United States resulted in this
book. It was conceived and edited by Forest Service managers and
scientists. The state-of-the-art summary of science and management of
riparian areas is especially pertinent because it addresses the diversity of
conditions and values that resource managers must address as they attempt
to manage riparian areas in the eastern United States that have fragmented
ownerships, fragmented ecosystems, and diverse interest groups.
The book is published by CRC Press, costs $54.95, and can be purchased
from their web site (www.crcpress.com) or from your local book seller.
Reprinted with permission from CRC Press, LLC.
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