Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s –...
Transcript of Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s –...
![Page 1: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/1.jpg)
Lake Sammamish
Water Level Issues
-
Feb. 2015
![Page 2: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/2.jpg)
Lake Sammamish residents
are concerned about lake
water levels
![Page 3: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/3.jpg)
High water damages
shorelines
and improvements
Here’s are examples…
![Page 4: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/4.jpg)
Lake Sammamish Jan 2006
![Page 5: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/5.jpg)
![Page 6: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/6.jpg)
High Water Damages
![Page 7: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/7.jpg)
![Page 8: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/8.jpg)
![Page 9: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/9.jpg)
![Page 10: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/10.jpg)
![Page 11: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/11.jpg)
The long term effect?
Loss of Property
![Page 12: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/12.jpg)
The OHWM Is Our Shoreline Property Line
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10 – 15 ft.
![Page 14: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/14.jpg)
What’s causing prolonged raised
water levels?
![Page 15: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/15.jpg)
2013 County Study Finds…
“… statistically significant increasing trends
[in water levels] at the 27.0-, 27.5-, and
28.0-foot NGVD levels that were suggested
as being attributable to altered
maintenance protocols.”
![Page 16: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/16.jpg)
Effective Drainage
Is Key To
Lake Level Control !
![Page 17: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/17.jpg)
How did we get here?
![Page 18: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/18.jpg)
1960’s – Corps Built Sammamish River Flood Control Project (FCP)
(County to maintain annually)
1990’s – “Trial” Plantings Agreed to By Corps
(County reduces maintenance to once in 4 Years)
2000 – Corps Warned County “Maintenance Inadequate”
(“Notify lake residents of potential flooding”)
2004 – Bellevue OHWM Study (Proposed Raising OHWM)
2008 – Corps Inactivated Entire Flood Project
(“Fails standards”)
2010 – Residents’ Evaluation & Appeal to Agencies
Chronology of Key Flood Control Events
![Page 19: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/19.jpg)
HISTORY: Extracted from USACE FLOODPLAIN STUDY
** NOTE: King County claims to trim alternate sides every 2 years.
**
1960’s Corps’ Floodway at Marymoor
(Cross section of Floodway)
150 ft.
15 ft.
High Flow Channels
![Page 20: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/20.jpg)
Samm. River Floodway
The “Slough”
![Page 21: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/21.jpg)
Samm. River Floodway
The “Slough”
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Flow
A Closer Look at the Weir
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Marymoor Park
Redmond
Weir
Corps of Engineers’
Flood Control at
Marymoor Park
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1960’s – Corps Built Sammamish River Flood Control Project
(County to maintain annually)
1990’s – Corps agrees to “Trial” Plantings
(County reduces maintenance to once in 4 Years)
2000 – Corps Warned County “Maintenance Inadequate”
(“Notify lake residents of potential flooding”)
2004 – Bellevue OHWM Study (Proposed Raising OHWM)
2008 – Corps Inactivated Entire Flood Project
(“Fails standards”)
2010 – Residents’ Evaluation & Appeal to Agencies
Chronology of Key Flood Control Events
![Page 25: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/25.jpg)
HISTORY: Extracted from USACE FLOODPLAIN STUDY
** NOTE: King County claims to trim alternate sides every 2 years.
**
35 ft.
1990’s Corps Agreed to Trial Plantings
150 ft.
Trial Plantings
15 ft.
![Page 26: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/26.jpg)
To Lake
Samm.
To
Redmond
Weir
![Page 27: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/27.jpg)
1960’s – Corps Built Sammamish River Flood Control Project
(County to maintain annually)
1990’s – “Trial” Plantings Agreed to By Corps
(County reduces maintenance to once in 4 Years)
2000 – Corps Warns County: “Maintenance Inadequate”
(“Notify lake residents of potential flooding”)
2004 – Bellevue OHWM Study (Proposed Raising OHWM)
2008 – Corps Inactivated Entire Flood Project
(“Fails standards”)
2010 – Residents’ Evaluation & Appeal to Agencies
Chronology of Key Flood Control Events
![Page 28: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/28.jpg)
Adapted From: King County Willowmoor Project Report
~ 60 days
1965 – 1995 Daily Average Lake Level
~ 60 days
OHWM
![Page 29: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/29.jpg)
Adapted From: King County Willowmoor Project Report
~ 60 days
Daily Average in Lake Levels Compared
165 days
OHWM
1998 - 2013
1965 - 1995
![Page 30: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/30.jpg)
What did this look like to residents?
![Page 31: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/31.jpg)
# Days over OHWM DOUBLES in 7 Years
![Page 32: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/32.jpg)
1960’s – Corps Built Sammamish River Flood Control Project
(County to maintain annually)
1990’s – “Trial” Plantings Agreed to By Corps
(County reduces maintenance to once in 4 Years)
2000 – Corps Warns County: “Maintenance Inadequate”
(“Notify lake residents of potential flooding”)
2008 – Corps Inactivates Entire Flood Project
(“Fails to meet standards”)
2010 – Residents’ Evaluation & Appeal to Agencies
Chronology of Key Flood Control Events
![Page 33: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/33.jpg)
2010
Yet, residents still not informed
about threat of flooding!
![Page 34: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/34.jpg)
Residents Dig Deeper
![Page 35: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/35.jpg)
Residents Find Reduced Outflows at the Weir
Lake Elev. (ft NGVD)
FL
OW
(
ft3/s
ec)
YEAR
48%
Flow Loss!
![Page 36: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/36.jpg)
Weir Visible Here
Jun. 2010
Center of Channel/Flow
Conditions
Overgrowth in Floodway
![Page 37: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/37.jpg)
Agency Officials Meet with Residents (2010)
![Page 38: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/38.jpg)
1960’s – Corps Built Sammamish River Flood Control Project
(County to maintain annually)
1990’s – “Trial” Plantings Agreed to By Corps
(County reduces maintenance to once in 4 Years)
2000 – Corps Warns County: “Maintenance Inadequate”
(“Notify lake residents of potential flooding”)
2008 – Corps Inactivates Entire Flood Project
(“Fails to meet standards”)
2010 – Residents’ Evaluation & Appeal to Agencies
2011 – County Resumes Annual Maintenance
Chronology of Key Flood Control Events
![Page 39: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/39.jpg)
Maintenance Is Increased
![Page 40: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/40.jpg)
No. Days Lake Over 27 ft. per year
0
50
100
150
200
250
'65 to
'95
Avg.
2010
2011
2012
2013
2014
2015
2016
Prj'
ctd
We were making progress…
Increased maintenance
![Page 41: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/41.jpg)
No. Days Lake Over 27 ft. per year
0
50
100
150
200
250
'65 to
'95
Avg.
2010
2011
2012
2013
2014
2015
2016
Prj'
ctd
We were making progress…
Increased maintenance
![Page 42: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/42.jpg)
Current Floodway Conditions
Looking South – Lake WSE = 26.75’ (NGVD)
WEIR
< Sediment removal stopped here
Flow
![Page 43: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/43.jpg)
Sediment causes this
< Sediment removal stopped here
![Page 44: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/44.jpg)
Location: North End of TZ
Example Obstructions
![Page 45: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/45.jpg)
Location: Mid-TZ
Example Obstructions
![Page 46: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/46.jpg)
“Trial” Plantings Over Twice the Approved Width
85 ft + (instead of 35 ft)
![Page 47: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/47.jpg)
And -
Photos downstream of Bear Creek
Obstructions continue to be allowed downstream.
![Page 48: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/48.jpg)
Location: Park Entrance
Example Obstructions
![Page 49: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/49.jpg)
Location: Park Entrance
![Page 50: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/50.jpg)
County’s Solution
-
The Willowmoor Project
![Page 51: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/51.jpg)
Willowmoor Project
Preferred Alternative
![Page 52: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/52.jpg)
What’s Needed? PRIOR TO PROJECT -
Clear TZ to Corps’ cross section, including:
- sediment and obstruction removal
- “trial” plantings trimmed to 10 ft. width
- assurance of safe, small craft navigability
Corps of Engineers approval that Willowmoor a step to re-activation
Modernize weir to better manage outflow/ lake levels
POST WILLOWMOOR -
Assurance of annual maintenance of floodway to original design
Establish process to identify and correct downstream obstructions
![Page 53: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/53.jpg)
What’s Needed PRIOR TO PROJECT -
Clearance of TZ to Corps’ cross section, including:
- sediment and obstruction removal
- “trial” plantings trimmed to 10 ft. width
- assurance of safe, small craft navigability
Corps approval that “Willowmoor meets FCP standards”
Modernize weir to better manage outflow/ lake levels
POST WILLOWMOOR -
Assurance of annual maintenance of floodway to original design
Establish process to identify and correct downstream obstructions
![Page 54: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/54.jpg)
What’s Needed? PRIOR TO PROJECT -
Clearance of TZ to Corps’ cross section, including:
- sediment and obstruction removal
- “trial” plantings trimmed to 10 ft. width
- assurance of safe, small craft navigability
Corps approval that “Willowmoor meets FCP standards”
Modernize weir to better manage outflow/ lake levels
POST WILLOWMOOR -
Assurance of annual maintenance of floodway to original design
Establish process to identify and correct downstream obstructions
![Page 55: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/55.jpg)
What’s Needed? PRIOR TO PROJECT -
Clearance of TZ to Corps’ cross section, including:
- sediment and obstruction removal
- “trial” plantings trimmed to 10 ft. width
- assurance of safe, small craft navigability
Corps approval that “Willowmoor meets FCP standards”
Modernize weir to better manage outflow/ lake levels
POST PROJECT -
Assurance of annual maintenance of floodway to original design
Establish process to identify and correct downstream obstructions
![Page 56: Lake Sammamish Water Level Issuessensibleshorelines.org/.../Jan...Presentation1.pdf1960’s – Corps Built Sammamish River Flood Control Project (FCP) (County to maintain annually)](https://reader034.fdocuments.us/reader034/viewer/2022051807/6006d38e9719272089772d26/html5/thumbnails/56.jpg)
What’s Needed/ PRIOR TO PROJECT -
Clearance of TZ to Corps’ cross section, including:
- sediment and obstruction removal
- “trial” plantings trimmed to 10 ft. width
- assurance of safe, small craft navigability
Corps approval that “Willowmoor meets FCP standards”
Modernize weir to better manage outflow/ lake levels
POST PROJECT -
Assurance of annual maintenance of floodway to original design
Establish process to identify and correct basin drainage issues
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Residents seek your support
to protect and maintain
our properties
Support our recommendations via City
representative at the Flood Control District.
Actively participate in Willowmoor’s design, keeping
public informed of its progress.
Use Corps’ OHWM for shoreline permits; not one shifted
higher due to lack of TZ maintenance.
Organize other cities to develop a long-term,
basin-wide drainage management plan.