Cedar and South Street Area Flood
Cedar and South Street Area Flood
Remediation Project
Remediation Project
HEC-RAS Model Cross Sections
Cross Section
Locations
Existing Conditions
Overbank water flows
west along Cedar
Channel capacity exceeded
between 1 or 2 year event
Overtops roadway between
10-year and 25-year event
Overtops roadway between
5-year and 10-year event
25-year Flood Limits
Channel capacity exceeded
at a 10 year event
Overtops roadway at a 25 year event Bradley Street
Channel capacity exceeded at a 10-year and 25-year event Between South Street and Bradley St. Culvert
Overtops roadway between a 10-year and 25-year event South Street Culvert
Channel capacity exceeded at a 1 or 2 year event Between Cedar Street and South St. Culvert
Overtops roadway between a 5-year and 10-year event Cedar Street Culvert
Channel capacity exceeded at a 10 year event Between Arch St. Culvert and Cedar Street
Flow is contained within the channel upstream of the Arch St 60' RCP culvert. Downstream of the Arch Street culvert flow exits the channel primarily on the eastern side. Backwater upstream of Cedar Street forces water to the west down Cedar Street. The channel between the Arch Street culvert and Bradley is insufficient to convey the flows between the 1-year and 25-year storm events as described below.
Summary of Flooding Impacts/Reduction:
NA Properties Required to Implement Alternative:
Existing conditions
Alternativ e Description:
Existing Conditions
Alternativ e:
Cedar and South Street Flood Remediation Project - Alternatives Assessment
Alternative A
Channel capacity exceeded
between 2 and 10 year event
Overtops roadway between
25-year and 50-year event
Overtops roadway between
10-year and 25-year event
Channel capacity exceeded
Between 25 and 50 year event
Overtops roadway between a 25-year and 50-year event Bradley Street
Channel capacity exceeded between 25-year and 50-year event Between South Street and Bradley St. Culvert
Overtops roadway between a 25-year and 50-year event South Street Culvert
Channel capacity exceeded between 2-year to 10-year events Between Cedar Street and South St. Culvert
Overtops roadway between a 10-year and 25-year event Cedar Street Culvert
Channel capacity - between 25-year and 50-year events Between Arch St. Culvert and Cedar Street
Summary of Flooding Impacts/Reduction:
Three houses on South St. and the roller rink property. Properties Required to Implement Alternative:
Channel Modifications: none other than removing sediment from the Cedar
Street culvert.
Basins: This alternative considers 18 acre-feet of off-line storage in basins
bounded by Chargin Rd, South St, and the existing channel. Flow would be diverted from the channel downstream of the Pine St or Arch St culvert outlets and discharged back into the channel downstream of Cedar St. Some flow would be maintained in the channel between the points of diversion and discharge to minimize channel permitting issues. The basins would be constructed with a setback from the existing channel bank. This alternative would require culvert crossings of Pine St and Cedar St.
Alternativ e Description:
A
Alternativ e:
Alternative B
Channel capacity exceeded
between 10 and 50-year event
Overtops roadway between
25-year and 50-year event
Overtops roadway between
50 and 100-year event
without modification
Channel capacity
-100 year event
Overtops roadway between a 25-year and 50-year event Bradley Street
Channel capacity exceeded between 25-year and 50-year event Between South Street and Bradley St. Culvert
Overtops roadway between a 25-year and 50-year event South Street Culvert
Channel capacity exceeded between 10-year to 50-year events Between Cedar Street and South St. Culvert
Overtops roadway between 50-year and 100-year without culvert modifications Cedar Street Culvert
Channel capacity - 100-year Between Arch St. Culvert and Cedar Street
Summary of Flooding Impacts/Reduction:
Three houses on South St. and the roller rink property. Properties Required to Implement Alternative:
Channel Modifications: This alternative considers channel modifications from the outlet
of the Arch St. culvert to South Street. A minimum channel top width of 10' with vertical channel banks wa s created for the man-made bank sections of the channel because of space limtiations. More natural sections were widened where space was available to increase channel conveyance capacity. Sediment should be cleaned from the Cedar Street culvert. Improvements to the Cedar Street culvert should also be considered.
Basins: The basins as described in Alternative A are also included in this alternative. Alternativ e Description:
B
Alternativ e:
Cedar and South Street Flood Remediation Project - Alternatives Assessment
Alternative C
Channel capacity exceeded
between 10 and 50-year event
Overtops roadway between
25-year and 50-year event
Overtops roadway between
50 and 100-year event
without modification
Channel capacity –
100- year event
Overtops roadway between 25-year and 50-year event Bradley Street
Channel capacity exceeded between 25-year and 50-year event Between South Street and Bradley St. Culvert
Overtops roadway between a 25-year and 50-year event South Street Culvert
Channel capacity exceeded between 10-year to 50-year events Between Cedar Street and South St. Culvert
Overtops roadway between 50-year and 100-year without culvert modifications Cedar Street Culvert
Channel capacity - 100-year Between Arch St. Culvert and Cedar Street
Summary of Flooding Impacts/Reduction:
Three houses on South St. and the roller rink property. Properties Required to Implement Alternative:
Channel Modifications: This alternative considers channel modifications from the outlet
of the Arch St. culvert to South Street as described in Alternative B.
Basins: This alternative increases the storage capaisty of the existing basin to the east
of Chagrin Rd by 25%. The basins as described in Alternative A are also included in this alternative. Alternativ e Description: C Alternativ e:
Alternative D
Channel capacity
exceeded between
25 and 50-year event
Culvert capacity –
100-year event
Culvert capacity
– 100-year event
Channel capacity –
100- year event
Upstream Detention
maintains water
surface elevations at
or below existing levels
Overtops roadway between 25-year and 50-year event Bradley Street
Channel capacity exceeded between 25-year and 100-year event Between South Street and Bradley St. Culvert
Culvert capacity - 100-year event South Street Culvert
Channel capacity exceeded between 25-year to 50-year events Between Cedar Street and South St. Culvert
Culvert capacity - 100-year event Cedar Street Culvert
Channel capacity - 100-year Between Arch St. Culvert and Cedar Street
Summary of Flooding Impacts/Reduction:
No private property acquisition Properties Required to Implement Alternative:
Culvert - 4'x6' box culvert, connect culverts from exisiting basin and eastern
watersheds
Basins: 4.3 and 0.07 ac-ft at bypass culvert inlet Alternativ e Description:
D
Alternativ e:
Cedar and South Street Flood Remediation Project - Alternatives Assessment
