Bank Swallow Response to Rock Revetment Removal on the Sacramento River, California
Ron Melcer Jr. Adam Henderson
California Department of Water Resources Floodway Ecosystem Sustainability Branch
Photo: Dan Brown
Bank Swallow Riparia riparia
Hirundinidae
Photo: Jim Dunn
Photo: Eddie Bartley
Bank Swallow – California Populations Riparia riparia
Photo: Steve Hampton
Bank Swallow – Habitat Requirements Riparia riparia
• Vertical banks or bluffs • Friable soils • Source of renewal
Photo: Jim Dunne
Bank Swallow – Habitat Not Made to Last Riparia riparia
Bank Swallow – Habitat Not Made to Last Riparia riparia
Bank Swallow – Habitat Not Made to Last Riparia riparia
Bank Swallow – Linked to River Process Riparia riparia
Bank Swallow – Linked to River Process Riparia riparia
RM 166 - 1999 RM 166 - 2009
Bank Swallow – Impacts to Habitats and River Processes Riparia riparia
SepAugJulJunMayAprMarFebJanDecNovOct
22500
20000
17500
15000
12500
10000
7500
5000
Month
Dis
ch
arg
e (
cfs
)
Pre-Shasta Dam (1901-1944) Pre-Trinity Imports (1945-1964) Current (1965-2011)
• Changes in flow regimes • River bank stabilization • Loss of foraging habitat
2020201020001990198019701960195019401930
50
40
30
20
10
0
35000
30000
25000
20000
15000
10000
5000
Year
Re
ve
tme
nt
(Lin
ea
r M
ile
s)
Ba
nk
Sw
all
ow
Bu
rro
ws
State Threatened
Bank Swallow – Sacramento River Reach 4 Riparia riparia
Red Bluff
Corning
Hamilton City
Ord Bend
Butte City
Colusa
Bank Swallow – Sacramento River Reach 2 - 3 Riparia riparia
Bank Swallow – Recovery of Sacramento River Populations Riparia riparia
Habitat Protection
Artificial habitat
Bank Protection Removal
Bank Swallow – Recovery of Sacramento River Populations Riparia riparia
Habitat Protection
Artificial habitat
Bank Protection Removal
Methods: Aerial photographs (NAIP and other imagery) USACE 1991 Atlas DWR 1978 Atlas Channels 1896-1999 (DWR) Rip-rap Dataset (DWR) Bank Swallow Survey Dataset (1999-2012)
Bank Swallow – Response to Revetment Removal Riparia riparia
Would Bank Swallows respond to the removal of bank protection along the Sacramento River?
Methods: Aerial photographs (NAIP and other imagery) USACE 1991 Atlas DWR 1978 Atlas Channels 1896-1999 (DWR) Rip-rap Dataset (DWR) Bank Swallow Survey Dataset (1999-2012)
Bank Swallow – Response to Revetment Removal Riparia riparia
Would Bank Swallows respond to the removal of bank protection along the Sacramento River?
Methods: Aerial photographs (NAIP and other imagery) USACE 1991 Atlas DWR 1978 Atlas Channels 1896-1999 (DWR) Rip-rap Dataset (DWR) Bank Swallow Survey Dataset (1999-2012)
Bank Swallow – Response to Revetment Removal Riparia riparia
Would Bank Swallows respond to the removal of bank protection along the Sacramento River?
Bank Swallow – Response to Revetment Removal Riparia riparia
Red Bluff
Corning
Hamilton City
Ord Bend
Butte City
Colusa
RM 237L
RM 233R
RM 233.4L
RM 227L
RM 232L
RM 196.5R
RM 185.9R
RM 198.8L
RM 208L
RM 174R
RM 154R
Bank Swallow – Results Riparia riparia
Bank Swallow – Response to Revetment Removal Riparia riparia
Bank Swallow – Response to Revetment Removal Riparia riparia
Bank Swallow – Response to Revetment Removal Riparia riparia
Bank Swallow – Response to Revetment Removal Riparia riparia
No data 2006
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1200
1000
800
600
400
200
0
# o
f B
urr
ow
s
Bank Swallow – Response to Revetment Removal Riparia riparia
BANS return within 2 years to the site; in 2007-2008, > 1000 burrows at site
Revetment fails
Bank Swallow – Response to Revetment Removal Riparia riparia
Bank Swallow – Response to Revetment Removal Riparia riparia
Bank Swallow – Response to Revetment Removal Riparia riparia
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
200
150
100
50
0
# o
f B
urr
ow
s
Bank Swallow – Response to Revetment Removal Riparia riparia
BANS return within 3 years to the site; in 2003, > 200 burrows at site
Revetment Fails
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
200
150
100
50
0
# o
f B
urr
ow
s
Bank Swallow – Response to Revetment Removal Riparia riparia
BANS return within 3 years to the site; in 2003, > 200 burrows at site
Revetment Fails
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
200
150
100
50
0
# o
f B
urr
ow
s
Bank Swallow – Response to Revetment Removal Riparia riparia
BANS return within 3 years to the site; in 2003, > 200 burrows at site
Revetment Fails
Bank Swallow – Summary of Results Riparia riparia
• 11 sites located where revetment removed, failed, or no longer serving design purpose. • Approximately 3339 meters (11,018 ft) in total. • Average length 371 meters (240 m median length), or 800-1200 feet. • Most sites were probably the result of 1997 high water event • All but 1 site on alluvium; historic meander deposits.
Revetment:
Bank Swallow – Summary of Results Riparia riparia
• 10 of 11 sites were re-colonized by BANS • On average, sites were re-colonized in 2.5 years; (min = same year; max = 6 years) • Soil types at sites were mapped as Columbia, Gianella, moonbend, silty or sandy loam • Site that was not colonized did not form cut bank
Bank Swallows:
Photo: Jaime Chavez
Bank Swallow – Conclusions Riparia riparia
• We have empirically shown that BANS will re-colonize locations where bank protection is removed. • Sites are not large- there is habitat potential with modest modifications to the flood system. • BANS are likely habitat limited on the Sacramento River given their nearly universal response to novel habitats along the waterway. • Deliberate removal of revetment will likely provide more habitat to the species – affording benefits to other ecosystems and taxa. • We need to study where revetment removal makes the most sense based on flood management needs, and based on suitability for Bank Swallows (soil type, meander potential, etc). • Revetment removal in conjunction with conservation easements should be considered in providing breeding and foraging habitat.
Acknowledgements
CA Department of Water Resources (FESSRO) US Fish and Wildlife Service CA Department of Fish and Wildlife Bank Swallow Technical Advisory Committee Joe Silveira Dawn Garcia (Altacal Audubon) Greg Golet Ryan Martin Mike Bradbury Rachel Gardiner Eric Larsen Dan Brown Danika Tsao Jim Dunne Eddie Bartley Steve Hampton Maggie Smith Joan Humphrey And others...
Questions?
