Determining Average Cross-Sectional Area (A) |
| Transect #1 (upstream) |
|
Transect #2 (downstream) |
| ... |
Interal width
(feet) |
... |
Depth
(feet) |
... |
Interal width
(feet) |
... |
Depth
(feet) |
| |
A to B |
= |
2.0 |
|
1.0 |
(at B) |
|
A to B |
= |
2.5 |
|
1.1 |
(at B) |
| |
B to C |
= |
2.0 |
|
0.8 |
(at C) |
|
B to C |
= |
2.5 |
|
1.0 |
(at C) |
| |
C to D |
= |
2.0 |
|
0.5 |
(at D) |
|
C to D |
= |
2.5 |
|
0.4 |
(at D) |
| |
D to E |
= |
2.0
---- |
|
0.0
---- |
(shoreline) |
|
D to E |
= |
2.5
---- |
|
0.0
---- |
(shoreline) |
| Totals |
8.0 |
|
2.3 |
|
|
|
|
10.0 |
|
2.5 |
|
| Average depth = 2.3/4 = 0.575 feet |
|
Average depth = 2.5/4 = 0.625 feet |
| Cross-sectional area of Transect #1 |
|
Cross-sectional area of Transect #2 |
|
= Total width X Average depth
= 8.0 ft X 0.575
= 4.60 ft2 |
|
= Total width X Average depth
= 10.0 ft X 0.625
= 6.25 ft2 |
| Average area = (Cross-sectional area of Transect #1 + Cross-sectional area of Transect #2)/2 |
|
= (4.60 ft2 + 6.25 ft2)/2
=5.42 ft2 |
Figure 5.6
A sample calculation of average cross-sectional
area |
