"تقرير عن التنمية في بلاد الرافدين مع إشارة خاصة إلى تجديد أنظمة الأنهار" [‎٨] (٥٠/١٤)

8
The levels are taken from Sir William Willcocks's book and reduced to
feet:—
Slope of Tigris above and below Baghdad to the sea.
(Heights above mean sea-level.)
—
Distance
in
miles.
High
Flood
level
feet.
Low-
water
level
feet.
Range
feet.
Distance
between
points.
High
Flood
slope
per mile
inches.
Low
water
slope
per mile
inches.
Kassar Hassan Bey
0
362-87
339-58
23-29
Samarra
68-31
206-04
183-73
22-31
68-31
27-5
27-3
8heikh Mohamed Hassein
99-36
151-25
124-67
26-58
31-05
21-2
22-8
Baghdad .,
176-98
114-83
94-49
20-34
77-62
5-5
4-6
Baghdad
0
114-83
94-49
20-34
• •
Kut
214-34
57-41
39-37
18-04
214-34
3-2
31
Amara .,
366-56
28-54
21-32
7-22
152-21
2-2
1-4
Qualat Saleh
397-63
21-00
13-45
7-55
31-06
2-9
3-0
16-45
4-55
1-87
Ezra's Tomb
422-48
14-76
8-20
6-56
24-85
30
2-6
7-07
7-60
4-5
JCurnah
453-54
10-17
3-93
6-74
31-06
1-8
1-6
1-22
Basra .. • •
498-28
8-53
1-80
44-73
V Tidal.
Fao
561-41
8-56
•065
•
i
63'13
* *
-) High-flood, 2'77 inches per mile.
Baghdad to Kurnah. >
) Low-water, 2 • 39 inches per mile.
The figures italicised opposite Qualat Saleh, Ezra's Tomb, and Kurnah are from
my own observations and differ considerably from Sir William Willcocks's. I do not
think the river has, within recent years, reached the low level at Qualat Saleh
assumed by Sir William Willcocks, as in that case it would be nearly dry and
all navigation would cease. The effect of the large effluents which leave the river
above Qualat Saleh and send a great deal of their water back through the marshes
at Ezra's Tomb, is to flatten the slope between Amara and Qualat Saleh and
largely to increase it between Qualat Saleh and Ezra's Tomb.
Veiocities.
(18) I am of opinion that the velocity of the Tigris has been greatly over
estimated, especially in the lower reaches where 4 miles per hour, or nearly 6 feet
per second, has been commonly quoted.
The velocity is influenced by depth as well as by slope, and between Amara
and Kurnah, with a slope of say 3 inches per mile, the depths in flood are such as
should by calculation give a velocity of 2 to 3 feet per second, or say 2 miles
per hour, and that is what I obtained from actual observation.
At Baghdad, in high-flood, the mean velocity probably reaches 5 to 6 feet
per second, and at Samarra 10 feet per second, or 6 to 7 miles per hour. Chesney