FLOOD05464

• County: Statewide
• Basin: Statewide
• Title: Reducing Losses In High Risk Flood Hazard Areas: A Guidebook For Local Officials
• Date: 1/1/1985
• Prepared For: FEMA
• Prepared By: Association of State Floodplain Managers
• Floodplain - Doc Type: Educational/Technical/Reference Information

the single channel region of the fan is the multiple channel region. The fan width along
the boundary between the single channel and multiple channel regions can be measured
from the topographic map, once the length of the single channel is known.

1. Single Channel Region

Within this. region, discharges, Q (in cubic feet per second), that correspond to the
various depth zone boundaries should be selected using the table below. This table was de-
rived from the relationship:

Q

=

280 D2.5

where D is the total depth in feet due to pressure head and velocity head.

Q

49.5

772

2770

6420

12000

D

0.5

1.5

2.5

3.5

4.5

Depth zones are designated from zone boundaries as follows:

Depth of
Zone

Depth of
Lower Boundary

Depth of
Upper Boundary

I
2
3
4

0.5
1.5
2.5
3.5

1.5
2.5
3.5
4.5

Discharges, Q (in cubic feet per second), that correspond to the various velocity
zone boundaries should be selected using the table below. This table was derived from the
relationship:

Q

=

0.13 V5

where V is velocity in feet per second.

Q

68

240

654

1510

3080

5770

V

3.5

4.5

5.5

6.5

7.5

8.5

Velocity zones are designated from zone boundaries as follows:

Zone
Velocity

Velocity of
Lower Boundary

Velocity of
Upper Boundary

4.0
5.0
6.0
7.0
8.0

3.5
4.5
5.5
6.5
7.5

4.5
5.5
6.5
7.5
8.5

C-l5