RESTORATION & VISION CONCEPTS
Sebastopol, California
c a l d e r c r e e k
2 calder creek vision plan
An ecological approach to recreation & stormwater management Sebastopol is a small, charming city known for its agricultural history and environmental ethos. The restoration of Calder Creek builds on this sensibility, bringing back the invigorating experience of a living stream to public spaces, and providing an inviting backdrop that creative and thoughtful urban design can respond to. Moreover, creek restoration here reestablishes watershed processes that build resilience to climate change and promote a natural processes-infused approach to integrated water management.
This Summary explores of Calder Creek restoration opportunities from Jewell Avenue to the Laguna de Santa Rosa. This project was focused on Ives Park, the city’s “central park”, with consultations with individual upstream property owners as well as “vision” level concepts for daylighting the creek through downtown Sebastopol.
Background
Draining a one square mile watershed, the creek initially traverses low hills and low density residential properties. Through these properties, willow riparian habitat along the creek supports songbirds, hawks, waders, aquatic birds, frogs, minks and river otters. While an 1886 newspaper article noted salmon in the creek, it was better known for a water wheel and wood slate dam, the latter which created a seasonal swimming pond. When the creek was engineered into a channel and also culverted into underground stormdrain pipes, its footprint was reduced, and flood flows increased in velocity. Eventually operation of the seasonal pond ceased, and the remaining creek area at Ives Park, with steep channel walls and floodable areas, became a management concern.
The creek remains in this straightened and hardened channel through Ives Park, and is otherwise forgotten through downtown. It outlets in the Railroad Forest, approximately three hundred feet downstream from the Joe Rodota Trail trailhead at Petaluma Avenue.
Above: Overview of Calder Creek
Restoration Concept and Vision
Plan opportunity areas
ives park
d o w n t o w n
sebastopol
r a i l r o a d
forest
3 “The riparian canopy of the
creek produces a zone of greater
evapotranspiration, offsetting
urban heat islands with shade
and spaces for relaxation and
respite...”
Forward-looking Creek Restoration
As climate change and population pressures
increase, the need for more housing,
preservation of biodiversity, and water
resource management is becoming more
acute. Restoration of Calder Creek, including
daylighting of culverted reaches and
reestablishing and reconnecting its floodplain,
creates a lower-maintenance option for
stormwater storage, groundwater recharge,
habitat and recreation. The restored channel
corridor provides greater capacity and
increases storage for those times when the
Laguna de Santa Rose backwaters. The riparian
canopy of the creek produces a zone of greater
evapotranspiration, offsetting urban heat
islands with shade and spaces for relaxation
and respite. This will be a benefit through Ives
Park as well as through any daylighted urban
areas.
At Ives Park, the proposed stream restoration
concept builds on the 2013 Ives Park Master
Plan, maintaining the existing uses of the park
while adding the necessary stream length and
meander for a “dynamically stable” stream
channel (one that erodes and deposits sediment
in balance to maintain its channel form). It
also widens and reconnects the stream to a
functioning floodplain, creating more space
for flooding or backwatering from extreme
storms. Within the creek corridor, picnicking,
trails, wading, informal nature exploration,
and a sculpture garden are all accommodated.
Options for modifying the Jewell Street/Willow
Street intersection were evaluated in terms
of pedestrian and vehicular movement, and
benefit to the creek and park. A proposed “T”
intersection was included in the Ives Park
Master Plan with Creek Restoration presented
here.
Beyond Ives Park, opportunities for Calder
Creek were explored from High Street to
Petaluma Avenue. In some cases, the culverted
creek crosses through private property.
Therefore, the Vision Plan shows possibilities
to demonstrate to property owners that the
buried creek as a potential attraction that
adds value to developments, while also serving
as a public asset for its flood management,
stormwater and habitat benefits.
With chronic flooding at Petaluma Avenue
due to sedimentation in the stormdrain pipes
and non-native trees obstructing flows in the
open-channel reaches of Calder Creek in the
Railroad Forest, this project also suggests
increasing flood capacity within the Railroad
Forest by removal of the railroad fill prism
and replacement of the trail with a boardwalk,
daylighting approximately three hundred feet
of the creek that is currently culverted and
allowing it to establish its own channel.
Acknowledgements
This project was made possible by a Switzer
Foundation Leadership Grant to the Waterways
Restoration Institute (WRI) with Wildling
Design Studio (Wildling), and the cooperation
of the City of Sebastopol.
4 1 New T Intersection
2 New park entry
3 Rose garden
4 Preserved redwood trees
5 Boardwalk trail section
6 New stage
7 Restored Calder Creek
8 Central green 9 Picnic area
10 Pedestrian bridge
11 Vehicular access bridge
Jewell Ave
Willow Street
1 2
3 4
5 6
7 7
8 9
9 9
9 16
16 10
10 11
12 13
14 15
CALDER CREEK RESTORATION INFORMS MASTER PLAN UPDATE
Ives Park master plan update
OVERVIEW
12 Baseball field
13 Pool
14 Playground
15 Sculpture Garden / High Entry
16 BBQ area
0 50’ 100’ 150’
5 Restoration of Calder creek creates a safe and
accessible interface to bring the public back
to the water’s edge, increases habitat, flood
storage and groundwater infiltration.
A portion of the existing vertical channel wall
is maintained to protect a stand of redwood
trees. A deck is cantilevered over this wall,
with an overlook crossing the creek at the
current outlet location, marking a terminus
of an accessible loop trail around the creek. A
pedestrian bridge protects a city sewer main
within its alignment, while another bridge is
rated for vehicular access. The design modifies
an existing sculpture garden and uses the
riparian canopy as a backdrop for some of the
artwork. The playground and a bbq area are
shifted to accommodate the creek, while the
stage is relocated along the creek to create a
large central green with seating upslope from
performances.
With a geomorphic approach to restoring the
channel, wide floodplains also accommodate
trails, relaxing, exploration, play and habitat.
Preliminary grading focused on an equilibrium
stream and accessible pathways, inviting all
users to experience the creek. Terracing and
some vertical walls area also used to achieve
this. The increase in varied terrain creates new
sightlines and points of interest within the
park.
Facing Page: Master Plan Update with Creek
Restoration
Above: Section through creek near upper
Jewell entry looking upstream towards
pedestrian bridge with protected sewer
line, and in the distance, redwoods,
boardwalk and overlook.
Right: View of park entry from High Street
with sculpture garden in the foreground.
Landscape terracing in the background
balances an accessible walkway with the
creek’s geomorphic equilibrium channel
design approach.
stage boardwalk & deck overlook low terrace & seat walls north entry overlook 5 5 1 6
6 High StreetS. Main Street
6 Downtown vision concepts
2 High street - s. main street
1 Daylighted Creek
2 Boardwalk
3 Overlook
4 Promenade
5 Seating area
6 Creek access
7. Walkway
Through downtown Sebastopol, public and
private parking areas are shown converted
back to a daylighted Calder Creek. Due to site
constraints, there is a naturalized creek bed
with vertical channel walls.
Between High and Main Street, these narrow
constraints in one area result in cantilevered
boardwalks along the edges, with one stretch of
boardwalk crossing through the creek corridor.
This is to provide support and protection for an
existing city sewer main.
CALDER CREEK can inspire new amenities and attractions
3 2
Top: Vision Concept for daylighting Calder
Creek between High and S. Main Streets.
Above right: A daylighted Calder Creek can
create an open space amenity for future
urban design if desired by property owners.
Opposite page, top: Vision Concept for
daylighting Calder Creek between S. Main
Street and Petaluma Avenue.
Opposite page, left: A promenade leverages
the urban cooling and shade provided by
the daylighted Calder Creek corridor, with
outdoor dining and socializing.
S. Main Street
Petaluma Avenue
Petaluma Avenue
7 A long-term solution to backwaterrelated flooding at Petaluma Avenue that also builds habitat resilience is
to remove the railroad fill that the
current trail sits above, replacing
it with a boardwalk that allows the
daylighted stream to manage its
own course.
1 3
s. main street - Petaluma Avenue
railroad forest
5 3
5 4
7 6
Between Main Street and Petaluma Avenue, the
creek creates a visual focus along a promenade
that includes a side path gently sloping to the
creek bottom. A narrower walkway completes
a loop around the channel while maintaining
some parking. This promenade includes
extended terraces for seating ideal for future
dining, from food truck “food courts” or
restaurants associated with new development.