Volume 2-05, Chapter 3 - City of Wichita

Section 3.2.4 - Grassed Channel
3.2.4 Grassed Channel Primary Water Quality Facility
Description: Vegetated open channels designed to
filter stormwater runoff and meet velocity targets for the
water quality design storm event.
KEY CONSIDERATIONS
DESIGN CRITERIA:
• Longitudinal slopes must be less than 4%
• Flow velocities in the channel must be less than 1 ft/s for
the WQ storm
ADVANTAGES / BENEFITS:
• Can be used as part of the runoff conveyance system to
provide pretreatment
• Grass channels can act to partially infiltrate runoff from
small storm events if underlying soils are pervious
• Often less expensive to construct than curb and gutter
systems
DISADVANTAGES / LIMITATIONS:
• May require more maintenance than curb and gutter
system
• Cannot alone achieve the 80% TSS removal target
• Potential for bottom erosion and re-suspension
• Standing water may not be acceptable in some areas
• Cannot be used on steep slopes
L
POLLUTANT REMOVAL
Total Suspended Solids
STORMWATER MANAGEMENT
SUITABILITY
Water Quality Protection
Channel Protection
On-Site Flood Control
Downstream Flood Control
IMPLEMENTATION CONSIDERATIONS
H
L
L
Land Requirements
Relative Capital Costs
Maintenance Burden
Residential Subdivision Use: Yes
High Density/Ultra-Urban: No
Drainage Area: 5 acres max
Soils: No restrictions
Other Considerations:
• Curb and gutter replacement
L
L
No Data
Nutrients – Total Phosphorus & Total Nitrogen
Metals – Cadmium, Copper, Lead & Zinc
Pathogens – Coliform, Streptococci & E. Coli
L=Low M=Moderate H=High
Volume 2, Technical Guidance Page 3 - 61