Volume 2-05, Chapter 3 - City of Wichita

Section 3.2.5 - Enhanced Swale
3.2.5
Enhanced Swale
Primary Water Quality Facility
Description:
Vegetated open channels that are
explicitly designed and
constructed to capture
and treat
stormwater runoff within dry cells formed by check
dams or other means.
KEY CONSIDERATIONSS
DESIGN CRITERIA:
• Longitudinal slopes must be less than 4%
• Bottom width of
2 to 8 feet
• Side slopes of 3:1 or flatter required
• Convey the on-site design storm event with 1 foot minimum
freeboard
ADVANTAGES / BENEFITS:
• Combines stormwater treatment with
system
runoff conveyance
• Often less expensive than curb and gutter
• Reduces runoff f velocity
• Aesthetic improvement
DISADVANTAGES / LIMITATIONS:
• Higher maintenance than curb and gutter systems
• Cannot be used
on steep slopes
• Possible resuspension of sediment
• Concerns with aesthetics of 4”-6” highh grass in residential
areas
MAINTENANCE
REQUIREMENTS:
• Maintain grass heights of approximately 4 to 6 inches
• Remove sediment from forebay and channel
POLLUTANT REMOVAL
H
M
Total Suspended Solids
Nutrients – Total Phosphorus & Total Nitrogen
STORMWATER MANAGEMENT
SUITABILITY
Water Quality Protection
Channel Protection
On-Site Flood Control
Downstream Flood
Control
IMPLEMENTATION
CONSIDERATIONS
H Land Requirements
M Relative Capital Costs
M Maintenance Burden
Residential
Subdivision
Use: Yes
High Density/Ultra-Urban: No
Drainage Area: 5 acres max.
Soils: No restrictions
Other Considerations:
• Permeable soil layer (dry swale)
L=Low M=Moderate H=High
M
No Data
Metals
– Cadmium, Copper, Lead & Zinc
Pathogens – Coliform, Streptococci & E. Coli
Volume 2, Technical Guidance
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