Watershed & Storm Sewer Dashboard

8414 Forney Road · Dallas, Texas · DEV Tracking No. PAV-DRNG-26-000005

Pre-dev Q: 237.7 CFS Post-dev Q: 406.5 CFS FEMA Zone AE / X
3.716
Watershed area (acres)
6.96
Lot design Q (CFS)
24%
Impervious cover
406.5
Peak Q — 100-yr (CFS)
Storm Event
2-year
10-year
50-year
100-year
Rainfall depth (24-hr)9.69 in
Watershed peak Q406.5 CFS
Lot Q — System 16.96 CFS
Roof Q — System 22.12 CFS
Tc (System 1)10 min (min.)
CN post-dev93
Map Layers
Lot boundary
Watershed boundary
Prairie Creek
Railway
Entrance road
Pipe network
FEMA Zone AE
Nodes / inlets
Nodes
CB #1 — NW Grate Inlet
System 1 — Driveway
RIM 525.01 · INV OUT 520.75
Q = 6.96 CFS · 18" HDPE out
CB #2 — NE Curb Inlet
System 2 — Roof drainage
RIM 525.68 · INV OUT 520.05
Q = 2.12 CFS · 12" HDPE out
JB #1 — Junction Box NW
HDPE → Concrete transition
18" HDPE in → 18" Concrete out
JB #2 — Junction Box NE
HDPE → Concrete transition
12" HDPE in → 12" Concrete out
Outfall — 21" Public Main
Forney Rd — Both systems
BM 524.89 · Total Q = 9.08 CFS
Pipe Sizing
NW HDPE (CB1 → JB1)
18"
✓
NW Concrete (JB1 → Out)
18"
✓
NE HDPE (CB2 → JB2)
12"
✓
NE Concrete (JB2 → Out)
12"
✓
Existing public main
21"
✓
Reference
City of Dallas DDM (September 2019)
NOAA Atlas 14, Vol. 11, Dallas County
CE Consulting LLC — Sheet C1.0, C05.01
HEC-HMS · Rational Method · Manning's Eq.