# CURRENT PROJECTS

# 

**Pool and weir fishway hydraulics**

Project Number: 09023 and 09054

Initiated: 1996

Status: Ongoing; extended as 09054

Location: CAFRL Flume Complex

# This investigation began primarily as a hydraulic modeling study of pool and weir fishways, but was modified as opportunities arose to biologically evaluate new fishway designs and modifications to existing fishways. Initially, a Hell's Gate type vertical slot fishway was replicated at full scale in the CAFRL flume facility and underwent several modifications (slot widening, raising of sill block invert elevation, alternation of slots) to improve its passage efficiency for American shad, *Alosa sapidissima*. Underwater video and PIT tag telemetry were used to record pool-to-pool movements of individual tagged fish. None of the modifications significantly improved passage, and it was concluded that the relatively high fixed slope of the fishway (1:10) induced extensive turbulence and air entrainment (even at minimal flows) that were not favored by American shad. Reduced scaling of the design from its original dimensions at west coast installations may have exacerbated turbulent hydraulic conditions. Additional pool and weir fishways that have been evaluated include the Cipoletti Weir and Labyrinth Weir.

# 

**Investigation of migratory behaviors and passage technologies for
American eels**

Project Number: 09032, 09056

Initiated: 1995

Status: Ongoing; combined as 09056

Location: Northeastern US (field study)

Recruitment of catadromous American eels (*Anguilla rostrata*) to
freshwater in North America has been shown to be declining, although the
causes are unknown. Passage facilities for upstream and downstream
migrant eels are lacking at hundreds of hydroelectric and other dams
along rivers and tributaries of the Atlantic coast, reducing recruitment
of eels into upstream habitats. Provision for upstream passage of eels
has been shown to enhance recruitment to historic habitats in upstream
sections of river currently blocked by dams. Several aspects of eel
passage are being investigated in this study, including development of
prototypes for upstream passes, age, growth, and life history traits in
upstream rearing habitats, downstream migratory behavior, and
technologies to reduce turbine entrainment and mortality. These focus
areas are critical for providing sound biological data, design criteria
and evaluation of passage structures, and a basis for future eel
mitigation efforts and enhancement of populations on a coastwide scale.

Evaluation of passage performance of adult American shad at lower
Connecticut River mainstem fish passage facilities

Project Number: 09042

Initiated: 1997

Status: Ongoing

Location: Connecticut River (field study)

Upstream and downstream fish passage facilities have been in place on
the lower Connecticut River mainstem (Vernon Dam, Turners Falls Dam,
Holyoke Dam) since 1981. The Turners Falls Dam fishway complex has been
historically inefficient in passing American shad (*Alosa sapidissima*).
This study evaluates passage performance of the Turners Falls fishways
by marking and releasing large numbers of American shad with passive
integrated transponder (PIT) tags and detecting tagged fish at strategic
sites within the fishways (e.g., entrances, exits, turnpools and
straight runs of pools) by automated PIT tag detectors. Data are
integrated to determine passage success or failure, rates of ascent,
delays, and passage \"bottlenecks\". The experimental design also allows
for experimental modifications of the fishways (e.g., lighting, flow
alteration, or limited physical modifications) to be implemented and
evaluated during testing. Overall, passage efficiency through the larger
fishways was low, averaging about 17%. Mean passage efficiency within
the power canal was 37% . Median transit times through the larger
fishways averaged 10 hours, but was highly variable between fish. Median
transit time through the canal was 25 days. Modifications to the
fishways (opening surface weirs in-line, replacing sharp-crested weirs
with chutes) improved efficiency and reduced transit times on a per-weir
basis, but modification of the entire fishway was predicted to have
produced a marginal improvement to the entire fishways, based on the
large number of weirs in each fishway. Addition of a secondary exit
channel out of the canal is expected to improve canal passage
efficiency.

## Hydraulic phenomena and their effects on downstream migrating anadromous fish

Project Number: 09043

Initiated: 1999

Status: Ongoing

Location: CAFRL Flume Complex

Recent initiatives to develop "fish friendly" turbines through which
fish can pass with little or no injury, stress, or mortality have raised
new questions about what characteristics of turbine design and operation
are directly responsible for injury or death of entrained fishes.
Hydraulic features such as hydraulic shear, physical strike, cavitation,
turbulence, and change in pressure may be deleterious effects, but
because direct observation of fish passing within a turbine has not been
made, the relative contribution of each effect is difficult to identify.
Experiments in the CAFRL hydraulic laboratory and flume complex have
investigated the direct and indirect effects of turbulence, shear, and
physical strike on fish. Exposure to nonlethal but moderately turbulent
environments was found to debilitate fish by incurring intensive
swimming, resulting in exhaustion and decreased sensitivity to external
stimuli, possibly resulting in increased susceptibility to predation.
Effects of hydraulic shear on fish passing by a simulated turbine blade
at test velocities 30 feet·sec^-1^ were observed to be relatively
benign. Injury and mortality of test fish striking the blade were found
to increase with both water velocity and thickness of the blade leading
edge.

## Migration of adult Atlantic salmon in the Penobscot River Basin, Maine

Project Number: 09059

Initiated: 2002

Status: Ongoing

Location: Penobscot River, Maine (field study)

In 1967, the Maine Atlantic Salmon Commission and the U. S. Fish and
Wildlife Service initiated a program to restore Atlantic salmon (*Salmo
salar*) to a number of Maine rivers, with the most significant effort
targeting the Penobscot River. During the 1960s, installation and
improvements in upstream fish passage facilities and reintroduction of
donor stocks were intended to restore large self-sustaining runs of
anadromous Atlantic salmon to the Penobscot. Despite extensive
enhancement efforts, and a number of years during the 1980s with
substantial spawning escapement above the lower-most dam , natural
reproduction has failed to replace the parent spawning population. This
study is designed to address a number of identified information needs
related to achieving the unified goal of self-sustaining restoration of
Atlantic salmon to its historic range in the Penobscot River. These
include upstream migration rates and attrition of adult salmon, their
ability to reach quality spawning grounds, the management and
disposition of available broodstock, and the effectiveness of current
juvenile stocking practices. The study employs an array of PIT (passive
integrated transponder) antennas on fish passage structures of the
mainstem Penobscot River and some of its tributaries. Adult salmon
trapped at the lowermost dam are tagged with PIT tags and released;
their progress to other upstream dams and passage through existing
fishways and bypasses is continuously monitored. Data on migration rate,
passage success, delays, and attraction to passage structures are
collected and analyzed. These techniques have also provided an
opportunity to expand investigations to address restoration plans and
strategies for other native diadromous and potamodromous (resident
river) fish species, including white sucker (*Catostomus commersoni*).

#### PAST PROJECTS

# Hydraulics and biological evaluation of Alaska Steeppass and simple Denil fishways

Project Number: 09020

Initiated: 1996

Status: Completed 2000

Location: CAFRL Flume Complex

Although simple Denil and steeppass fishways were originally designed
for upstream passage of adult salmonids, they are increasingly used for
passage of nonsalmonid species. These fishways are relatively
inexpensive to construct and maintain, can operate under a wide range of
natural discharge (headpond) conditions, and are primarily suited to
smaller streams and low head dams. However, the performance of
Denil-type fishways has rarely been evaluated with respect to passage of
anadromous clupeids, and their efficiency in passing these species has
been difficult to determine. A 4 ft Denil and deepened 18 inch Model A
Alaska steeppass fishway were evaluated in the CAFRL flume complex for
measurement of hydraulics and passage performance under semi-controlled
conditions, with American shad (*Alosa sapidissima*) and blueback
herring (*A. aestivalis*) as the study species. Fishway slope and
headpond were varied (independent variable) and passage of through each
fishway were measured as percent of fish passed per unit time and amount
of time required to ascend each fishway (dependent variable). Although
increasing slope and decreasing headpond generally decreased passage
efficiency for both species, there was also an interaction of slope and
headpond on percent passage and transit times. Water temperature was
positively correlated with percent passage and negatively correlated
with transit time under certain conditions.

## Hydraulic model study of Little Falls Dam fish passage

Project Number: 09028

Initiated: 1994

Status: Completed 1998

Location: CAFRL Flume Complex

Little Falls Dam on the Potomac River, Maryland, historically blocked
upstream passage of Ameican shad (*Alosa sapidissima*), alewife (*Alosa
pseudoharengus*), blueback herring (*Alosa aestivalis*), and other
anadromous fish species at moderate to low flows. An engineered notch in
the dam was considered to provide passage while maintaining upstream
reservoir capacity. Maximum flow velocities through the notch also had
to be less than those that could be negotiated by target migratory fish.
Hydraulic modeling studies undertaken in the CAFRL hydraulic laboratory
produced a novel design that employed a series of labyrinth weirs. Based
on these studies, a full-scale prototype notch (4\' deep x 24\' wide)
with a series of three labyrinth weirs was designed and constructed in
the crest of the dam 75 feet from the Virginia shoreline. The notch
passes adequate flow (325 cfs) and the weirs dissipate the water energy
and provide adequate depth such that fish can swim to upstream spawning
grounds. The US Army Corps of Engineers completed the engineering design
and specifications and construction of the notch took place in the
winter of 2000. The fish passage structure is operational and has been
biologically monitored.

**Evaluation of burst swimming performance of upstream migrant fishes**

Project Number: 09030

Initiated: 1993

Status: Completed 2003

Location: CAFRL Flume Complex

Knowledge of locomotory and energetic capabilities of upstream migrant
fishes is essential for determining their ability to negotiate and
ascend riverine obstructions and passage structures, where water
velocities and turbulence can be high. Maximum burst speeds, durations
and distances of ascent under rectilinear flow conditions were
determined for eight species of anadromous and potamodromous (freshwater
riverine) fishes over a range of water velocites up to 4.5 m/sec,
including Ameican shad (*Alosa sapidissima*), alewife (*Alosa
pseudoharengus*), blueback herring (*Alosa aestivalis*), white sucker
(*Catostomus commersoni*), striped bass (*Morone saxatilis*) and walleye
(*Stizostedion vitreum*). Other measures of swimming performance were
evaluated, including acceleration rates, discontinuous swimming patterns
(burst-and-coast mode) and the relationship between tailbeat frequency
and absolute swimming speed. The results of this study are used as
baseline fish behavioral data for the design and evaluation of upstream
fish passage structures (e.g., notches through dams, culverts, and
fishways).

## Large scale and live bed pier scour experiments

Project Number: 09038

Initiated: 1998

Status: Completed 2001

Location: CAFRL Flume Complex

The accurate prediction of sediment scour depths near bridge piers under
design storm conditions is important in bridge design. Underprediction
of scour can result in costly bridge failure and possibly the loss of
lives and over prediction can result in millions of dollars wasted on a
single bridge. The physical processes involved are very complex and
difficult to analyze; thus most design scour depth predictions are made
using empirical equations or scale model test results. An ongoing bridge
scour research program at the University of Florida is directed at
increasing our understanding of scour processes and improving the
accuracy of design scour depth predictions. A cooperative study between
CAFRL and the University of Florida (co-funded by the U.S. Department of
Transportation) was undertaken to investigate scour depth in CAFRL's 20
ft wide flume. Large scale pier scour experiments were completed for two
grain sizes of sand (D50=0.5mm & 0.8mm) and three sizes of piers (d=4.5
in, 12 in, & 36 in). Depth of scour holes was found to be less than that
predicted by existing equations. The current study\'s findings have
provided the data necessary to formulate more accurate scour prediction
equations.

**Estimation of Atlantic salmon smolt passage and outmigration in the
Connecticut River by remote acoustic telemetry**

Project Number: 09047

Initiated: 1999

Status: Ongoing

Location: Connecticut River (field study)

Increased effort in stocking Atlantic salmon (*Salmo salar*) smolts and
fry in the Connecticut River has not resulted in increased adult
returns, indicating decreases in return rates of hatchery and
stream‑reared smolts. The poor return rate may be a result of losses of
smolts during downstream migration due to delays caused by dam
impoundments, turbine mortality, or predation. However, these losses had
not been quantified and summarized on a cumulative, basin‑wide level.
This study investigated movements of acoustically telemetered
fry-stocked smolts in the Connecticut River mainstem released at a point
200 km upstream of the river mouth. The technique employed arrays of
datalogging receivers sited at locations above and below the two
lowermost mainstem hydroelectric dams. The collected data yield
information on migratory rates in dammed and undammed mainstem reaches
(e.g., delays), progressive losses of smolts due to turbine mortality or
predation, and behaviors upon entry into the estuarine and marine
environment. Migration rates between dams ranged from 9.1 to 78.0 km/d,
with an average rate of 52.3 km/d. Smolts displayed rapid downstream
movements soon after release, but were delayed up to several days at
each dam. An average of 20-25% of migrating smolts released above the
two dams reached the estuary within 4 to 10 days after release and
appeared to spend little time within the tidal reach of the estuary.