Drainage System at King Abdulaziz University (KAU)

Osama El-Quqa, Luis Galindo, Sarah Seraj

Flooding at Jeddah and King Abdulaziz University

Nov 25, 2009: 3.5” of rain in 4 hrs. 472 casualtiesJan 26, 2011: 4” of rain in 4 hrs. 160 casualties

Annual Rainfall = 2.1”

Area around university was badly hitNearby highway knocked downAECOM called to emergency action

Scott Edelman FloodList

Location and Characteristics of KAU

Jeddah

Airport

KAU

Basic Basemap

Digital Elevation Model Basemap

Proposed Project• Design drainage system at KAU

• Reduce probability of flooding

• Assuming one large watershed• Water flows to detention pond at lowest point

Alternatives

Alternative Distance

A: To Northern Channel 8.7 km

B: To Southern Channel 8.5 km

C: To Red Sea 4.5 km

A

CB

Time

Inte

nsity

(mm

/hr)

Jeddah Aggregated Rainfall

HEC-HMS Model

• Watershed Parameter Calculations • Area: ~6.138 Km2

• Impervious: 53%• Curve Number: 87• Initial Abstraction: 7.59 mm• Lag Time: 216 min

HEC-HMS Model

10 year 50 year 100 year 500 year0

1

2

3

4

5

6

7

Precipitation Graph

P (mm) Pe (mm)

Prec

ipita

tion

(in)

0:00 6:00 12:00 18:00 0:000

10

20

30

40

50

Unit Hydrographs

Direct Flow, 10 yearDirect Flow, 50 yearDirect Flow, 100 yearDirect Flow, 500 year

Time (hour)Fl

ow m

3/s

Detention Pond Design (100 year flood)Calculating storage volume using straight line method • Jeddah Stormwater Design Manual 2011• Surface water flow into Red Sea from West of Jeddah = 4.6m3/s (Subyani 2009)

19:59 23:59 3:59 7:59 11:59 16:00 20:000

5

10

15

20

25

30

Pre-project hydrographStraight line outflow

Time (hrs)

Flow

(m3/

s)

Q=4.6 m3/s

Storage volume reqd = 388,000 m3

Future Work

• Complete HEC-HMS model

• Full design of detention pond

• Pipe/channel network