Slide 1
An Overview of the GWK Retention Treatment Facility and The August 11, 2014 Wet Weather Event
August 19, 2014
Slide 2
Overview Elements
1. Brief History of the GWK Drainage District and GWK
Retention Treatment Facility
2. Design
3. Operations
4. August 11, 2014 Wet Weather Event
5. Next Steps
GWK Drainage System
GWK System Map
GWK System Map: Clawson Vicinity
Towards GWK RTF
Slide 6
GWK RTF Design: Criteria
The GWK RTF is a Pollution Control Facility that
screens out sanitary trash and other solids and
provides disinfection using chlorine before
discharging to the Red Run Drain.
Chlorine contact time and wet weather volume
storage provided using the 124 Million Gallons of
storage capacity available in the facility.
Slide 7
GWK RTF Design: Criteria
Designed to address flows from a 10-year, 1-hour
design event. Peak flow rate into the GWK RTF ≈
3.1 Million Gallons per Minute (7,000 cfs).
GWK RTF construction and upgrades were required
to reduce Combined Sewage Overflows (CSOs) and
be in compliance with MDEQ rules and the Federal
Clean Water Act.
Slide 8
GWK RTF Design: Extent of Pollution Control Facility
Slide 9
GWK RTF Design: Original Influent Weir
Slide 10
GWK RTF Operations Explained: Operator’s Walk-through
Slide 11
August 11, 2014 Wet Weather Event: Event Statistics
WRC has a network of rain gauges that provide
rainfall depth from every wet weather event.
Rain Gauge 0880 is located at the GWK RTF and is
used to determine rainfall amounts for much of the
GWK RTF service area.
Slide 12
August 11, 2014 Wet Weather Event: Event Statistics
Rainfall frequency is determined by referencing
published texts.
At the time of the GWK RTF design “Technical Paper
40” was a reference text.
Today. “NOAA Atlas 14” is the reference text.
Slide 13
August 11, 2014 Wet Weather Event: Radar Rainfall
Slide 14
August 11, 2014 Wet Weather Event: Radar Rainfall
Slide 15
August 11, 2014 Wet Weather Event: Comparison to Design Event
10:0010:30
11:0011:30
12:0012:30
13:0013:30
14:0014:30
15:0015:30
16:0016:30
17:0017:30
18:0018:30
19:0019:30
20:0020:30
21:0021:30
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Design Event Recorded Rainfall
Rain
fall
Dept
h (in
ches
)
Slide 16
August 11, 2014 Wet Weather Event: Effect on GWKDD and RTF
August 11, 2014 Wet Weather Event: Effect on GWK RTF
Slide 18
August 11, 2014 Wet Weather Event: Effect on GWK RTF
August 11, 2014 Wet Weather Event: Effect on Red Run Drain
Red Run at GWK Outlet (Dequindre)
August 11, 2014 Wet Weather Event: Effect on Red Run Drain
Red Run at Mound Red Run at Van Dyke
Slide 21
August 11, 2014 Wet Weather Event: WRC Next Steps
Collect community data from basement flooding
Hydraulic study of the GWK facility
Slide 22
Oakland County Executive Office Announcement
“The flooding impacted thousands of individuals who now have many questions about how to recover from this disaster. The Multi-Agency Resource Center (MARCs) will be an opportunity to meet with experts who can answer some of those questions.”
– L. Brooks Patterson
The Southfield MARC will be open 11 a.m. – 7 p.m. Wednesday and Thursday at the Southfield Pavilion, 26000 Evergreen Road south of the I-696 expressway.