Qhafor Ameen Hamasur

Chapter Two
Geology of the study area
runoff can be calculated roughly according to Danderkar and Sharm (1989)
equation as below:
R= (P-17.8) x P/254
Where: R=Surface runoff in cm.
P=Annual rainfall in cm.
R= (74.1 cm-17.8 cm) x 74.1cm/254 cm
R =16.42 cm=164.2mm=0.1642m
The catchment area of the Basara stream at the study area equals 572.8 km 2
(=572.8 x 10 6 m 2 ), Fig (2-27), so the total amount of water from surface runoff
equals 94.053 x 106m 3 / year (=0.1642m x 572.8 x 10 6 m 2 ).
From the above calculation, it appears that the amount of water which comes
from groundwater discharge of Tainal (Bazian) and Tilie streams is equal to
37.07x10 6 m 3 /year (=131.123 x 10 6 m 3 –94.053 x 10 6 m 3 ), which is due to the
existence of highly permeable rocks of Sinjar, Pila Spi, Injana (its sandstone
beds), Muqdadiya(its sandstone and pebbly sandstone beds) and Bai Hassan
Formations in most parts of the catchment area except some parts covered by
Kolosh Formation. The reservoir area of the proposed dam is composed mostly
of Fat'ha and Injana (its claystone beds) Formations have a good ability of the
retention of water in the reservoir area.
Reservoir area (Ar) and volume (Vr) curves are presented in Fig (2-28) and (2-
29) respectively. Reservoir volume curve shows that the total amount of
discharge (131.123*106m3/year) corresponds to an elevation of 730m above sea
level, and at this elevation, the area impounded by the reservoir is 6.25km 2 (see
Fig“2-28”).
Sediment amount that would enter and be settled in reservoir is estimated to
be 612 m 3 /km 2 /year (ITSC, 2007), which is equal to 350553.6m 3 /year comes from
the total catchment area and approximately equals to 20 x 10 6 m 3 during 57 years.
This volume (20 x 10 6 m 3 ) corresponds to an elevation of 702m above sea level.
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