In 2008, Cramer Fish Sciences (CFS) was awarded a grant from the U.S. Fish and Wildlife
Service (USFWS) Anadromous Fish Restoration Program
(Grant #813328G012), for the
Lancaster Road Side Channel and Floodplain Restoration Project (Project). Key goals of the
Project were to rehabilitate and enhance productive juvenile salmonid rearing habitat in
the Stanislaus River; and determine project effectiveness with an efficient and scientifically
robust monitoring program. In order to adaptively implement restoration from its inception to
its completion, the project was conducted in three phases: Phase I - Design, Outreach and
Permitting; Phase II - Implementation; and Phase III - Post-implementation monitoring and
continued outreach. The CFS team worked closely with the local community and resource agencies
throughout each phase of the project.
L-R: View of the Lancaster
Road side channel shown before construction (July 20, 2010), after construction
(January 1, 2011), and inundated at ~3000 cfs after construction (April 18, 2012).
[Click each picture to view in high resolution]
Phase I of the project began during fall 2008 and included plan development for project design,
monitoring, community outreach, pre-project monitoring, and fulfilling construction regulatory
requirements. The CFS team worked with engineers and local landowners to define project goals
and design standards, develop specific monitoring objectives to measure project success, and
finalize a project design plan. Phase II included site construction, regulatory monitoring,
and ongoing public outreach activities. Phase III began immediately after construction and
included post-construction implementation, effectiveness, and validation monitoring; fulfilling
post-construction permitting requirements; and ongoing public outreach activities.
Final construction included development of a side channel and three tertiary channels. Following
construction, total Chinook Salmon fry habitat increased about threefold depending on flow,
although this decreased slightly after two years of monitoring. Total juvenile Chinook Salmon
habitat nearly doubled in the project site; relative increase in habitat was dependent on flow.
This resulted in increasing average Chinook Salmon abundance in the restored areas by 2013.
Juvenile steelhead habitat increased slightly post-construction, and increased more substantially
two years after project completion.
VISION AND GOALS
The Project vision is to restore critical habitats for
juvenile salmonids and, in coordination with local communities and stakeholders, promote
recovery of healthy and diverse Chinook salmon and steelhead populations in the Stanislaus
River, while helping meet the AFRP abundance goals. This vision fits into the framework of
salmonid population recovery on the Lower Stanislaus River and is aligned with the following AFRP goals to:
1) involve local partners in the implementation and evaluation of restoration actions;
2) improve habitat for all anadromous life stages through improved physical habitat; and,
3) collect fish population, health, and habitat data to facilitate evaluation of restoration
actions (USFWS 2001). The vision also meets objectives outlined in previous planning efforts
for the Stanislaus River (CFS 2009) by working to improve our understanding of Stanislaus
River salmonid population dynamics.
The Stanislaus River Restoration Plan was used to help identify critical limiting factors
and knowledge gaps in order to assess and prioritize research and habitat restoration actions
for these valuable resources. The Restoration Plan also provided a basis to recommend both
adaptive restoration and applied research specific to this project to more effectively address
AFRP goals. Within this context we developed the following goals for the Project:
- To serve as an example of publicly-supported applied fisheries and restoration science;
- To rehabilitate and enhance productive juvenile salmonid rearing habitat in the LSR; and,
- To determine project effectiveness with an efficient and scientifically-robust monitoring program.
These project-specific goals fit into the framework of AFRP, and meet the AFRP and CALFED requirement
to use adaptive management in planning, design, and implementation (CALFED 2001).
Regional location of the Lancaster Road Side Channel Restoration Project, Stanislaus River, CA.
Inset maps show the project site in relation to the state of California and surrounding cities.
Below is an aerial view of the project area, showing the geographical extent of the project site
and the side channel and tertiary channels (TC1-TC3) that were constructed. The Stanislaus River
flows from right to left.
CFS employee taking flow measurements to understand how restoration actions affected river depth and velocity.
CFS employs three types of monitoring to investigate the impacts of restoration projects: implementation
monitoring; effectiveness monitoring; and validation monitoring. The goal of implementation monitoring
is to determine whether the restoration project was executed according to the design plan and whether
it met the original goals, specifically with respect to physical structure and hydrology. The main goal
of effectiveness monitoring is to determine whether the project met restoration objectives. Site-specific
effectiveness monitoring tracks physical conditions and biological responses necessary to provide productive
rearing for juvenile salmonids. Validation monitoring is carried out to determine if the basic assumptions
behind the project conceptual model are valid. For this project, validation monitoring consisted primarily
of evaluating whether side channel construction restored floodplain processes.
Monitoring projects sought to answer such questions as:
- Do constructed topography/bathymetry and duration and magnitude of flooding match design plans?
- Following restoration, does the channel inundate at flow levels present during the juvenile rearing period?
- Was there an increase in inundation duration and habitat availability?
- Was the side channel utilized by juvenile Chinook Salmon and steelhead, and were juveniles associated
with specific habitat characteristics (depth, velocity, vegetative cover)?
To determine if the construction met project goals, CFS compared the "as-built" elevations to the
specified elevations. The following figure shows that of the entire side channel footprint, ~70% of
survey points were on grade (0.01 in. accuracy). Of the remaining area, 46% was on average 0.19 in.
too high, and 54% was 0.20 in. too low. These data suggest the site was constructed appropriately
to design specifications.
Comparison of channel bathymetry for site designs and post construction at the
Lancaster Road Restoration Project, Stanislaus River, CA. Yellow indicates little to no change,
blue indicates lower areas than specified, and red indicates higher areas than specified.
Bathymetric comparison of pre- (A), immediately post (B), and ~22 months
post-channel construction (C). This figure highlights the connection of the side channel to
the main reach of the river, and shows how flow changed, including in the tertiary channels,
For Chinook Salmon juveniles, Weighted Usable Area (WUA) nearly doubled immediately following
construction under 900 ft3/s flows, from 530.4 m2 WUA (7.4% of total wetted area) to 1001.3 m2
WUA (12.1% of total wetted area). There was also a substantial increase in WUA under the higher
flow conditions, with an additional 545 m2 WUA under 1200 ft3/s and 493.5 m2 under 1500 ft3/s,
and corresponding increases in the percent of wetted area with suitable juvenile Chinook Salmon
habitat. Following two seasons of periodic inundation, WUA remained relatively constant, with
habitat increasing by 12.2-44.2 m2 (0.1%-0.5% wetted area) depending on flow.
River 2D modeling visual representation of modeling results for Chinook Salmon
juvenile habitat before restoration (PRE), immediately after restoration (POST 1), and two years
following restoration (POST 2), under three simulated flow conditions (900 ft3/s, 1200 ft3/s,
and 1500 ft3/s). Warm colors indicate higher quality habitat and cool colors indicate lower
CFS employee performing snorkel surveys to monitor use of the restored area by salmonids and other fish species.
Habitat use and abundance
Following restoration, the side channel inundated each year (2012 and 2013) for 30-60 consecutive
days. During this time, juvenile Chinook Salmon and steelhead utilized the side channel and tertiary
channels extensively. There were high Chinook Salmon abundances in both 2012 and 2013. In 2012,
steelhead were also abundant. Very few steelhead were observed in 2013; this may have been due to
an extremely high flow event (flows > 3000 ft3/s) that occurred in late April/early May, during the
time of year when juvenile steelhead are typically observed in the system. It is likely that juvenile
salmonids in both the main channel and the side channel were actively transported out of the system
by high stream velocities.
We generally did not observe significant abundance differences between the side channel and margin
(edge) habitat of the main channel following restoration. The River 2D model predicted that some
suitable salmonid rearing habitat would occur along the main channel bank margins, and these were
also the areas where the snorkel surveys could be safely conducted. In 2012, Chinook and steelhead
abundances in the side and tertiary channels were comparable with those observed in margin habitats
of the main channel control sites. In 2013, Chinook abundances were similar between the main channel
and side channel, but lower in two of the tertiary channels. The lower number of fish observed in
the tertiary channels were likely due to low flow conditions and lack of instream vegetative cover
in the tertiary channels. The two-dimensional model predicted that little suitable habitat would be
available in the tertiary channels under the lowest modeled flow conditions, and surveys conducted
under these conditions likely contributed to the lower average abundance in the tertiary channels.
In addition, there was less vegetative cover available in the tertiary channels as compared to the
side channel, and we observed a significant association with instream vegetative cover for both Chinook
Salmon and steelhead juveniles. It is important to note that the tertiary channels were constructed to
provide habitat at higher flows than those optimized in the secondary channel and this appears successful.
As has been found in previous studies, strong associations were observed between fish abundance and
vegetative cover features (large and small woody material, submerged trees, low-velocity edge habitat)
(Fausch 1993, Moyle 2002, Gard 2006, Beakes et al. 2012). These features provide increased structural
complexity, creating a refuge from high streamflow and predators in the main channel and promoting fish
production and survivorship (Willis et al. 2005; Schneider and Winemiller 2008). Studies on the Lower
American River suggest that, in addition to being associated with higher fish abundance, instream cover
features may also increase juvenile salmonid foraging behavior, provided that the cover feature provides
a velocity break (CFS 2013). These velocity breaks presumably allowed fish to allocate more energy
towards feeding and less towards maintaining position in the water column. The potential bioenergetic
benefits of inchannel structure to rearing salmonids have been described in several studies and have
been effectively used to predict microhabitat selection and fish density (Lehane et al. 2002, Hayes et
al. 2007, Jenkins and Keeley 2010, Urabe et al. 2010 Gustafsson et al. 2012). On the Stanislaus River,
predation from non-native fish species has also been identified as a potentially significant cause of
juvenile salmonid mortality, and cover features may also provide a refuge from top predators such as bass.
CFS employee performing drift net surveys to monitor drift macroinvertebrates in one of the tertiary channels, post-construction.
Food availability, particularly drift macroinvertebrates, is a critical but often discounted component of
juvenile salmon habitat restoration projects. The restored side channel and tertiary channels in this
study resulted in an overall increase in the total amount of aquatic and riparian habitat and, as a result,
undoubtedly increased the total amount of both aquatic and terrestrial invertebrate drift available as
prey to juvenile salmonids. The amount and type of drift at the study site varied by year and date and
was likely affected by the amount of time the stream channel was inundated, weather conditions, time of
day, and canopy. There is a real management need to develop methods and measures for monitoring and assessing
the quality and quantity of the food supply, particularly drift, to support juvenile salmonid growth in
restoration projects. This study was an important first step.
CONCLUSIONS AND RECOMMENDATIONS
The Lancaster Road side and tertiary channels provided suitable habitat characteristics (depth, velocity, and
vegetative cover) for juvenile Chinook Salmon and steelhead. The total area and relative proportion
of usable habitat was higher following construction under a range of flow conditions. Observations of
habitat associations in the side channel suggest that side channel habitats may offer an important refuge
from the prevailing high-velocity conditions in the main channel, and that the availability of instream
vegetative cover may be at least as important as depth and velocity metrics typically used to calculate
CFS employee core sampling to understand how placed gravel, cobble, and fines move over time due to river flow.
We did not evaluate residence time of juvenile salmonids in side channel habitat, as compared to the habitat
in the bank margins of the main channel. Future studies could examine whether the improved side channel
habitat conditions lead to higher retention and growth of juvenile salmonids prior to outmigration. Other
studies have shown that juvenile salmonids that spend more time rearing instream before emigrating enter
the ocean at a larger body size and have greater survivorship (Unwin 1997; Sommer et al. 2001; Woodson et
al., in press). Thus, enhancing low-velocity juvenile rearing habitats such as side channels and floodplains
has the potential to improve retention of juveniles in the river system, increasing the quantity and quality
of juveniles entering the ocean and likelihood of survival. This hypothesis could be tested by tracking fish
microhabitat utilization, retention, and growth in both the main and side channels using mark/recapture and