Side
af
764
Forrige
Næste
264
moleswoeth’s pocket-book
Navigable Rivers, &c.
SURFACE AND BOTTOM VELOCITIES OF RIVEHS.
V = Velocity of water at surface in ins. per second.
Velocity at bottom = (V + 1) — 2 VV.
Mean velocity
(V + 0-5)-Vv.
• 8 V in sluggish rivers.
Surface.
j Bottom.
Mean.
4
8
12
16
20
24
28
32
3-3
6
9
12
15
18-4
21-6
2’5
5-6
9
12-5
16
19-5
23-2
26'8
Surface Bottom. Mean. Surface. Bottom. Mean.
36 25 30-5 68 • 52-5 60-2
40 28-3 34-1 72 56'0 64'0
44 31-7 37-8 76 59'5 67-7
48 35-1 41-5 80 63-1 71-5
52 38-5 45-2 84 66-6 75-3
56 42 49 88 70-2 79-1
60 45'5 52-7 92 73-7 82-8
64 49 56’5 100 81 90-5
Obstructions in Rivers.
V = Velocity of river previous to obstruction in
feet per second.
A = Sectional area of river unobstructed in feet.
« = „ „ at obstruction in ft.
R =aRise of water caused by the obstruction in ft. ,
Table of Rise of Water occasioned by Obstructions.
Velo-|
Bise in Feet when Amount of Obstruction compared with
Sectional Area of River =:
V. To * io .«L 10 TO JL A
1 •01 •04 •07 •12 •20 •35 •67 1-60 6’63
2 •03 ■06 •12 •21 •35 •62 1-19 2’83 11’70
3 •04 •11 •21 ■36 •61 1-07 2-05 4-88 20’15
4 •07 •18 •33 •57 •97 1-70 3-27 7-75 32-00
5 •II •27 •50 •85 1-43 2-50 4-81 11-43 47-18
6 •15 •37 •69 1-18 1'99 3-48 6’71 15-93 65-75
1 • 1A V
Velocity caused by any obstruction = ————