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Sonoma Valley Watershed Station Work Plan
2000
Sonoma Ecology Center
Technical Advisory Committee
Research Program Work Plan
Sonoma Ecology Center, 205 First Street West, Sonoma, CA 95476
(707) 996-9744, [email protected], http://www.sonomaecologycenter.org
INTRODUCTION
The Sonoma Ecology Center’s Technical Advisory Committee (TAC) directs and guides the
research of the Sonoma Valley Watershed Station (SVWS). The TAC consists of Sonoma
Ecology Center (SEC) staff, local professionals, and scientific experts with background in
planning and implementing watershed research plans. The TAC's role of mentor for the SVWS
includes: designing of sampling protocols and data sheets, training volunteers and interns,
performing QA/QC of volunteer data, and conducting data analysis and interpretation.
As a community-based organization, SEC is charged with facilitating community
understanding of technical watershed data by collecting and integrating multiple types of
information. SEC also plays a key role by interpreting others’ scientific data and analyses in
terms people can relate to, whether they are policy-makers or concerned residents. In this
way, the SEC’s science programs promote the health and sustainability of Sonoma Valley
ecosystems.
Over the past two years, the SEC’s Sonoma Valley Watershed Station has been implementing
a research plan adopted by the TAC in 1997 to begin work on three goals:
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Restore salmonid fish populations
Preserve and restore riparian areas
Preserve and protect water quality and quantity
Self-sustaining populations of all native plant and animal species, including humans
The conditions that these goals seek to achieve are three strong indicators of healthy
ecological conditions necessary for sustainable communities. SEC is working towards these
(and other) goals that will help support natural and human systems to maintain Sonoma
Valley's high quality of life. In order to achieve these three goals, our work at the Watershed
Station has focused on three areas: establishing baseline values for evaluating stream
ecosystem health, measuring stream parameters critical to the survival of salmonids in
Sonoma Creek, and identifying priorities for future research and restoration activities.
As in the TAC work plans for 1996-1999, this work plan extends the studies already underway
and builds on them with new research objectives. The scope of work outlined in the plan
below applies to watershed research only and is not intended to detail restoration or
implementation measures. These programs are detailed in other documents.
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SVWS RESEARCH OBJECTIVES
Scientific research focused on restoration planning should follow a framework of questions to
define a process for watershed assessment.
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What are the desired conditions?
What are current, baseline conditions?
What are the obstacles to desired conditions? What are limiting factors? How do
they interact?
What can be done to alleviate the obstacles or remove them? What are the
options, opportunities, or alternatives for achieving desired conditions?
What is the community’s vision? Which alternatives fit the vision?
What is the sequence of steps required to accomplish the best alternative?
The research described herein applies this framework to five ecological indicators: water
quantity, water quality, sediment, plant communities, and wildlife. Specific research
objectives are identified for each indicator. In many cases, restoration activities will be
identified by the synthesis of data and integration of analyses.
1.0 Water Quantity
Many tributaries in our watershed have intermittent and ephemeral flow characteristics which
heighten the ecosystems’ sensitivity to changes in water quantity. Winter flows, including
peak flows are particularly important in maintaining channel morphology and function. Low
flows are critical in providing over-summering habitat for many aquatic species, including
salmonids. Land and water use by humans can have dramatic effects on the timing and
intensity of flow. The following water-quantity assessment will be conducted to monitor instream flow conditions, analyze effects on fish populations, evaluate the relationship to
human activities, and quantify the availability of water for human use.
1.1
PRECIPITATION
The watershed receives most of its precipitation in the form of rain, although occasional snow
falls in the headwaters of Sonoma Creek. The winter rains account for the annual input of
water into the watershed system, and provides a key baseline number for tracking the
response of streams to rainfall, as well as, water availability for human and natural needs all
year long.
During the rainy season, Stream Stewards will collect rainfall data daily. An automated rain
gage was temporarily installed last wet season and a permanent gage is planned for the
2000 season which will improve the quality and consistency of the data. An automated
monitor installed at the Sonoma Mission Inn Golf Course within the last year is recording
evapotranspiration potential.
1.2
DISCHARGE
1.2.1 PEAK FLOW
Flow within Sonoma Creek Watershed varies widely depending on rainfall, topography,
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and conditions within each tributary’s subwatershed. The interaction of these factors
influences in-stream sediment conditions, channel complexity, and other water-quality
parameters. Increases in peak intensity and length of time over which they are
sustained have been shown to cause changes in water quality and channel
morphology. Sediment moves during high flow events. Increases in peak flow from
changing land use practices (e.g., changes in vegetative cover, increased amount of
impervious surface) may cause increased stream power. Increased stream power can
result in accelerating downstream bank erosion, channel incision, loss of large woody
debris and complex channel morphology, and coarsening of streambed materials.
SEC has organized a collaborative funding strategy to establish an automated
station(s) in Sonoma Creek. The U.S. Army Corps of Engineers (USACE), U.S.
Geological Survey (USGS), and RWQCB have agreed tentatively to fund installation
and the critical first few years of operations for the station(s). SEC is probing local
agencies for long-term funding opportunities. The USGS will install the station and
perform operations and maintenance in following years, with technical assistance
from SVWS staff. We will fine-tune the peak-flow monitoring program to complement
the automated flow gauging system. Collection of discharge data by Stream Stewards
will resume after analysis of existing information is completed, following protocol
revision if necessary.
RESEARCH OBJECTIVES
 establish current conditions for monitoring trends
 compare current situation with historical data
 help analyze sediment data, calibrate sediment production model
 test relationship to instream habitat conditions (spawning gravel, etc)
 test relationship to land use
1.2.2 LOW FLOW
In a region with 6 months of drought, low flows are an important indicator of water
quantity. The interaction of low flow with water quality parameters is a critical link in
determining suitable habitat for many aquatic species, including steelhead.
Low flow evaluation was initiated in June 2000 and it will continue for three years.
Data will be collected during months when the stream potentially loses flow to a
lowered water table. Selected low flow monitoring locations are not only proximal to
known nursery habitat but are also under bridges with abutments where staff gauges
could be installed. A rating curve will be developed for each station to correlate stage
with discharge. With staff gauges installed and rating curves prepared, volunteer
monitors will be able to read streamflow conditions from the gauges.
RESEARCH OBJECTIVES
 establish baseline low flow values for monitoring trends in key tributaries
 compare current low flow values with historical data
 assess problem areas for fish rearing (pool numbers and depths)
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 link to water quality, temperature studies
1.3
GROUNDWATER
SEC is working in conjunction with the Sonoma County Water Agency to convert well log data
from 5000 sites in the valley to GIS-linked database files. SEC is also mapping groundwater
recharge zones. The land use data will be applied to determine the changes in soil
permeability from pavement. These groundwater data will be useful in determining the
amount of water potentially available (or unavailable) for new allocations.
1.4
SURFACE STORAGE
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WATER ALLOCATIONS/WATER BUDGET
Currently there is no system to evaluate water allocations and availability of ground and
surface water for withdrawal. This watershed is particularly sensitive to low flows during
months when water withdrawals are at their greatest. Summer water use has the potential to
severely limit steelhead populations and aquatic communities in general.
We will research water rights allocations and withdrawals within the watershed and
investigate how much water is being used by riparian and appropriative abstraction. Using an
estimate of the annual input from rainfall, we will examine the interaction of withdrawal timing
and amounts with expected and measured water available. This information will provide a
long-term monitoring tool to track how much water might (or might not) be available for new
allocations. The data will be examined on a sub-watershed basis where possible.
Research Objectives
 assess expected discharge from precipitation input and compare it with measured
discharge
 assess how and where fish habitat might be affected by groundwater and in-stream
withdrawals
 track how much water might (or might not) be available for new allocations
2.0 Water quality
Basic biological, chemical, and physical properties of streams are important indicators of
stream health and are crucial factors in determining the types and numbers of animal and
plant species that can survive within the wetted portion of the stream. Sonoma Creek is
presently listed as impaired for nutrients, pathogens, and sediment under Clean Water Act
Section 303(d). Possible sources of water-quality degradation include erosion, runoff, septic
systems, yard waste, oil and grease, and agricultural fertilizers and pesticides. Interpretation
of the biological, physical, and chemical information from water quality monitoring will help to
identify limiting factors for the steelhead population, pinpoint sites for further monitoring, and
provide a blueprint for ecological restoration in the watershed.
2.1
TEMPERATURE
Water temperature is an important factor for steelhead survival as well as an indicator of
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riparian canopy and stream health. Previous water monitoring reports have shown high
temperatures in sensitive stream reaches for steelhead. The link between temperature and
low flow is extremely important to understanding limiting factors for salmonids.
Stream stewards will continue to monitor water temperature at key sites. Analysis will be
integrated with other data about steelhead needs. The relationship between riparian canopy,
land use, and temperature will be evaluated.
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RESEARCH OBJECTIVES
compare current situation with previous data
identify problem areas for steelhead
link temperature to low-flow monitoring
test relationship with land use and riparian canopy
2.2
WATER CHEMISTRY
Water-quality monitoring will examine factors including but not limited to: dissolved oxygen
(DO), conductivity, and pH. Results of water-quality testing will be used to draw conclusions
about the specific parameters as they relate to stream health. Sampling will be conducted in
three teams, following the protocols developed by the EPA in Volunteer Stream Monitoring: A
Methods Manual. Analysis will build on existing studies based on EPA STORET data (“A day
on Sonoma Creek,” 1997).
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RESEARCH OBJECTIVES
establish baseline values for monitoring trends
compare current situation with historical data
identify point and non-point sources of pollution
identify problem areas for steelhead
test relationship of water quality to land use
identify restoration opportunities
2.2.1 PESTICIDES
Various chemical pesticides are used by agricultural, residential, and governmental
operations throughout Sonoma Creek Watershed. These chemicals have various risks
to human health, but their impact on terrestrial and aquatic ecosystems is mostly
unknown. Pesticides can be toxic to algae and BMIs, two primary aquatic food
sources, in relatively low concentrations. Recent research has also implicated
pesticides in behavioral and olfactory damage to salmonid individuals.
Monitoring for pesticide impacts starts with understanding which chemicals are being
applied where and in what quantity. Using Pesticide Use Report data from the county,
we will create a GIS database of pesticide use in the Sonoma Creek Watershed over
the past decade. We will identify high use areas and potential conflict areas for
salmonid populations. This data will be used to select pesticide monitoring sites.
RESEARCH OBJECTIVES
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establish trends using 10+ years of PUR data
compare high use areas to BMI monitoring and key steelhead reaches
assess relationship to land use
select water monitoring sites for pesticides
2.3
BENTHIC MACROINVERTEBRATES
Because of their diversity, ubiquity, and importance in the stream community as a major link
in the food web, benthic macroinvertebrates (BMIs) provide an important indicator of aquatic
health. BMIs are a major food source for salmonids and may be a limiting factor for survival
of juvenile fish.
In spring 2000 we began sampling BMIs using the California EPA Stream Bioassessment
Procedure at twelve sites. This protocol is a simplified version of EPA’s Rapid Bioassessment
Procedure; it prepares us to implement the Rapid Bioassessment Procedure next year. Joseph
Brumbaugh, a locally knowledgeable invertebrate biologist, is assisting in developing
macroinvertebrate key and tolerance categories and in training volunteers. Replicate samples
are being identified to family at the SVWS laboratory. The samples are grouped into three
pollution-tolerance categories and used to calculate a water-quality index. The results will be
analyzed to draw conclusions about the biological health of the sampled sites.
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RESEARCH OBJECTIVES
establish baseline community index values for monitoring trends
assess the biological health of key sites
test relationship to land use
identify restoration opportunities
3.0 Sediment
California’s Clean Water Act Section 303(d) lists Sonoma Creek as impaired by sediment.
Important beneficial uses include preservation of rare and endangered species, fish
migration, and instream freshwater habitat. Water quality objectives are included in the
RWQCB Water Quality Control Plan (Basin Plan) for the San Francisco Bay Region. The plan
says that turbidity (due to waste discharge) shall not increase by more than 10 percent where
natural turbidity is more than 50 nephelometric turbidity units (NTU). For nonpoint sources
(e.g., of sediment), no numeric value has been established, but surface waters are expected
to be free of changes in turbidity that cause nuisance or adversely affect beneficial uses.
Interpretation of the data relating to excessive sediment yield will help to provide information
to the community regarding human-induced sedimentation, identify turbidity-related limiting
factors for steelhead, pinpoint sites for continued monitoring, and identify restoration sites in
the watershed.
3.1
HILLSLOPE SEDIMENT PRODUCTION
The natural process of soil erosion can be accelerated by human activities. According to the
NRCS, natural soil erosion rates in watersheds similar to Sonoma Creek watershed, estimated
at 1 to 4 tons per acre per year, can more than double from land use changes. Sheet and rill
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erosion, which remove an approximately even layer of soil over large areas, can account for
the erosion of up to 10 tons of soil per acre without significant visual effect and more than 20
tons when gullies and rills form. Streambank erosion, caused by stream flows out of
equilibrium with their channels, can account for 300 tons or more of soil loss per acre per
year. Mass wasting, such as landslides and soil creep, although not quantified here, account
for large amounts of sediment loss in certain subbasins (e.g., Bear Creek subwatershed) in
Sonoma Creek watershed. When soil losses result in increased delivery of sediment to valley
streams, as is common in the rainy season, suspended sediment concentrations and stream
sediment bedloads can increase.
Hillslope sediment production in key subwatersheds of Sonoma Creek will be modeled with
GIS to estimate erosion rates. The GIS model will incorporate factors of the MUSLE (modified
universal soil loss equation), including slope, upslope catchment area, vegetation, and soil
type. Other factors will be examined and included as necessary, such as, road density, land
use, and bedrock geology. These factors are weighted and combined to predict the level of
sediment production. The resulting maps will indicate areas most prone to sediment
production. Sediment field data will be compared to predicted values for sediment production
from the GIS model. The analysis will focus on separating baseline sediment levels from
current sediment levels. The results should depict where sediment production is higher than
a predicted baseline erosion rate. We will evaluate the effects from different land uses on
sediment levels.
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RESEARCH OBJECTIVES
estimate baseline erosion rates
identify areas of high erosion potential, excessive sediment levels
test relationships between roads, land use, and sediment
identify restoration opportunities and priorities
3.2
TOTAL SUSPENDED SOLIDS, TURBIDITY
An important beneficial use potentially impaired by sediment is preservation of rare and
endangered species, such as steelhead trout. Feeding by resident juvenile steelhead may be
impaired in waters with NTU levels greater than 100. A clear stream of water generally has
turbidity values below 5 NTU.
Currently, no comprehensive program exists for assessing turbidity and sediment loadings in
Sonoma Creek. Methods to assess sedimentation include measuring rainfall, flow, total
suspended sediment (TSS) and/or turbidity and correlating among the parameters. With help
from interested agencies, we will re-establish an automated flow-gauging station in Sonoma
Creek for the purpose of continuously monitoring discharge as well as expand the Stream
Stewards Program to complement the continuous monitoring. Sampling sites will be chosen
for testing the hypothesis that land cover changes and management practices cause
significant increases in peak flow runoff and sediment input to streams.
RESEARCH OBJECTIVES
 establish baseline values for monitoring trends
 compare current situation with historical data and Basin Plan regulations
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link to GIS model of sediment production
identify problem areas for steelhead
test relationship of sediment to land use
identify restoration opportunities
3.3
STREAM CHANNEL MORPHOLOGY
Field reconnaissance was begun in previous years to gather preliminary information on the
condition of the stream banks and bed, overhead cover, large woody debris (for hydraulic
diversity), size of bed materials, and channel widths and depths. Work will continue on
morphological studies to monitor channel stability and structure, through visual observation of
planform channel changes, potential culvert/fish passage obstructions, and bank and bed
erosion (e.g., use of erosion pins as a simple way to quantify erosional changes).
In addition, stream channel cross sections and profiles will be studied and recorded to
establish a history of stream behavior. Over time, we will have a log of riverine changes that
may be linked to other changes in the stream system as they become known. We will review
existing information (e.g., as-built cross sections from bridge construction, planform
observations from aerial photos) and add our own cross-sectional data from select locations
surveyed with transit and rod.
Implement SFEI’s Watershed Science Approach in multiple sub-watersheds.
RESEARCH OBJECTIVES
 monitor current conditions to track trends
 establish historical trends to reach current condition
 identify problem areas and potential restoration activities
4.0 Plant Communities
Oak woodland and chaparral communities, which were identified by the California Gap
Analysis Program as communities of special concern, cover much of the watershed’s area.
The watershed’s mix of habitat types provides for a wealth of wildlife diversity. Upland plant
communities provide priceless ecosystem services, including soil stabilization, water quality,
groundwater recharge, run-off/peak flow mitigation, carbon storage, oxygen production, etc.
Vegetation community distribution has changed considerably over the last 150+ years of land
use change.
4.1
RIPARIAN VEGETATION MAPPING
Riparian zones play a critical role in ecological processes and support many terrestrial and
aquatic species. Changes in the extent, location, and composition of the riparian vegetative
canopy affect bank stability and sediment input to the channel, recruitment of large woody
debris to the channel for habitat complexity and cover, and stream temperatures. Riparian
dysfunction has been identified by Fish and Game as a limiting factor for salmonids, and its
impact can be felt by many species. The distribution of riparian vegetation is dynamic,
changing locally and watershed-wide from natural processes and human impacts.
Understanding trends in riparian vegetation is critical to restoration of riparian processes.
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Riparian condition will be monitored using aerial photographs, vegetation transects, and
visual stream surveys. Aerial photographs are available from the County to help document
historical changes to the riparian community. Riparian vegetation will be compared to
existing riparian setback zones to evaluate the effectiveness of these policies in protecting
riparian vegetation.
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RESEARCH OBJECTIVES
establish baseline values for monitoring trends
compare current situation with historical data and policy regulations
identify problem areas for steelhead
test relationship of riparian canopy to land use
identify restoration opportunities
link riparian conditions to other measures of stream health and function
4.2
RARE, THREATENED & ENDANGERED SPECIES
California’s floristic diversity is among the richest on Earth, and Sonoma County is home to an
abundance of plant species that contribute to this diversity. Many are rare and/or endemic.
Some of these species and a range of others are considered sensitive by state and federal
agencies. Because so much of the watershed is privately owned, there have never been
consistent surveys for occurrences of these species. Most surveys are done in preparation for
environmental documentation related to entitlement permits and development projects. The
California Natural Diversity Database attempts to track occurrences of these species on a
statewide basis, but the program is under-funded and has no resources to collect field data.
SEC will research occurrences of rare, threatened, and endangered plants in the watershed.
Unpublished reports, EIR’s, and other documents will be scoured for information about the
plants’ locations. A workshop or series of meetings with community botany experts could be
conducted to collect this data. After this initial scan for existing information, a needs
assessment will be conducted to determine opportunities for biological surveys.
RESEARCH OBJECTIVES
 make list of species of concern for Sonoma creek watershed
 expand NDDB GIS database using expert information and unpublished reports
 identify potential conflicts with preservation of species
4.3
UPLAND PLANT COMMUNITIES
SEC will continue efforts to map vegetation community types using field surveys, while
collecting and quality checking vegetation maps derived from satellite data. This information
will be used to monitor the distribution of vegetation over time and perform change detection
activities at a fine-scale. We will perform a watershed-wide gap analysis at a fine scale to
determine the level of protection afforded our wide diversity of habitat types. Vegetation
communities will be evaluated for connectivity and core habitat functions.
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RESEARCH OBJECTIVES
establish baseline conditions for monitoring trends
compare current situation to historical data
identify under-represented ecosystem types and prioritize habitat preservation efforts
evaluate core and connectivity functions
link to water quantity and aquatic ecosystem function studies
4.4
INVASIVE SPECIES
California’s plant communities are undergoing incredible transition in composition, and this
watershed is no exception. Exotic species have invaded almost all ecosystems of the
watershed, caused known and unknown effects on native species. Species requiring
immediate attention include Arundo donax, yellow starthistle, broom, tree of heaven, acacia,
eucalyptus, and others. In addition, the introduction of European annual grasslands has
changed almost the entire understory of oak woodlands. Some evidence has suggested that
this shift in composition could inhibit oak regeneration.
SEC is administrating a large CALFED grant for Team Arundo del Norte, which includes
funding for eradicating most of the riparian Arundo in the watershed above the Highway 121
bridge. Eradication will begin again in fall 2001, again utilizing significant volunteer
contributions of labor, working from the top of the watershed down. SEC will continue
mapping efforts, and evaluate the success of this restorative eradication effort to seek
improvements for implementation in other watersheds.
RESEARCH OBJECTIVES
 establish baseline distribution of A. donax and other exotics for monitoring trends
 compare current situation to historical data
 evaluate restoration strategies for success
5.0 Wildlife
The native fauna of our watershed includes an impressive collection of both migratory and
resident species. While some species have been displaced and eliminated from the
watershed, only one is completely extinct – the California grizzly. Wildlife are an important
part of our natural communities and a critical indicator for quality of life. Ultimately, questions
about the health of ecosystems must be referenced to species that live in the landscape. To
monitor and conserve wildlife species in the watershed, SEC is developing a focal species
approach by selecting species that represent healthy ecological conditions. Conservation
actions should be taken to meet resource requirements for focal species that have
demanding needs, so the needs of many other species can be met.
5.1
STEELHEAD POPULATIONS AND DISTRIBUTION
Steelhead are good focal species for watershed restoration planning because they rely on all
habitats of a river system. The success of steelhead is a good indicator of healthy water
conditions. Basic biological research is needed to understand and monitor trends in
steelhead populations. Steelhead have a complex life history that requires analysis of fish
populations through spawner surveys, out-migrant trapping, and overall population surveys.
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The first step in planning for species and instream habitat restoration is understanding trends
distribution. In Sonoma Creek Watershed, there is a range of information available about
steelhead and native fish distributions, but it has not been gathered or mapped in one place
for dissemination. Quantifying spawning activity is useful in understanding fish population
distribution and limiting factors to fish survival. Out-migrant trapping points to conditions
affecting the fish between the headwaters and the Bay.
SEC will develop a GIS database of salmonid distribution in the watershed using literature
review, expert interview, and other research techniques to gather existing information. Each
major tributary in the watershed will be labeled with the current and historical status of
salmonids. The map database will include known fish barriers, natural or manmade. The
barriers list will include any new places identified by SEC field work (see 5.3 Habitat
connectivity). Fish population surveys will continue one to three times per year for three
years. Surveys may use trapping, snorkeling or electroshocking methods. Key reaches will be
surveyed to determine numbers of salmonid redds. Spawner surveys are to be performed
during the January through April spawning period, by trained volunteers and community
members. Out-migrant traps will be placed just downstream of spawning and rearing areas,
as well as just upstream of tidally influenced areas, between March and May, when juveniles
move downstream.
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RESEARCH OBJECTIVES
establish current distribution of salmonids
compare current situation with historical data
identify natural and man-made migration barriers for salmonids
monitor the abundance, size, and distribution of fish in the watershed
measure the survival/mortality rate between the upper and lower watershed
integrate limiting factors data to identify restoration opportunities
determine appropriate goals for steelhead numbers
5.2
STREAM HABITAT
Steelhead have specific instream habitat requirements for various stages of their life history,
including spawning gravel substrate, escape cover, and shelter areas. These conditions are
created by various ecological factors, such as riparian function, channel morphology, large
woody debris, and other factors. SEC's spawning gravel report also provides data for some
important stream reaches. We will identify data gaps by gathering these existing data sources
and evaluating next steps for instream habitat research. Where available, the instream data
will be combined with other spatial data, including riparian vegetation, hillslope erosion
potential, and land uses to analyze streams with high priority for further study and habitat
restoration.
The fish distribution information will be used to prioritize new creek reaches for study of
spawning requirements and in-stream habitat characteristics. Spawning habitat monitoring
will include pebble counts, bulk sampling, and size distribution analysis of spawning gravels.
Habitat typing for the creek and large woody debris survey will be coordinated with DFG and
the GIS/GPS Program. Site-specific habitat features can be referenced to GPS and checked
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annually for stability and persistence.
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RESEARCH OBJECTIVES
establish baseline values for monitoring trends
compare current situation with historical data and policy regulations
identify the location and accessibility of spawning areas
assess instream habitat conditions for limiting factors
identify data gaps
identify restoration opportunities
5.3
KEYSTONE SPECIES FOR CORE HABITAT AND CONNECTIVITY
Habitat fragmentation is widely considered one of the greatest threats to biodiversity. By
splitting large ‘core habitats’ into smaller and more isolated pieces, many species can be
impacted by loss of dispersal options, inbreeding depression, lack of recolonization
opportunities in the event of natural disaster or chance, and loss of habitat. Large carnivores,
including mountain lion, bobcat, and coyote, require large spaces as body size can roughly
correlate with space needs. Many top predators have experienced habitat reduction and
fragmentation, yet these species appear to play a keystone role with top-down regulation of
ecosystems.
SEC has begun the process of evaluating core habitats and connectivity by identifying the
Sonoma Valley Habitat Corridor as one of the few areas with intact cross-valley habitat
connectivity. This analysis will be expanded to assess regional connectivity patterns and
context. Connectivity ‘choke-points’ will be identified using maps of habitat suitability, roads,
land use, and other barriers to animal movement. Site-specific research will continue to
identify appropriate design and restoration opportunities on properties within the habitat
corridor. A common barrier to movement is insufficient culverts. Some culverts are too small
for larger animals to safely walk through; some are too smooth for fish to navigate. Some
culverts have eroded footings that present barriers to fish passage. SEC biologists will identify
culverts that are hindering fish and wildlife movement and work with transportation agencies
to replace them with functional under- or over-crossings.
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RESEARCH OBJECTIVES
map habitat suitability for connectivity focal species
identify choke-points of habitat and threats to connectivity using development
scenarios
identify barriers to animal movement
evaluate significance of habitat areas based on connectivity and core functions
10. Social Systems
SEC is committed to using integrated analysis of research, such as the biophysical topics
detailed above, for efforts that can move our community toward a sustainable human
economy. To this end, we will continue to conduct investigations of, for example, watershed
carrying capacity, economic values of the environmental services of undeveloped land, and
comparisons of the projections of existing planning authorities with desired watershed
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conditions.
CONCLUSION
SEC’s SVWS continues to offer the expertise and a local connection that makes applied
watershed science a realistic tool for this community. Our work can assist the community
toward well-informed decision-making, and increase the options available to sustain our
natural heritage. We work with the knowledge that successes in this watershed can serve as
a model for other communities to better understand processes that affect their streams and
watersheds.
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