Water: Monitoring & Assessment
Figure 5.6
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 |
|||||||||||||