Application of Water Quality Index (WQI) as a possible indicator for agriculture purpose and assessing the ability of self purification process by Qalyasan Stream in Sulaimani …

An attempt has been made to use the calculated Water Quality Index (WQI) values for irrigation suitability and
livestock drinking purposes (water quality for agriculture) and also to use it as a possible indicator for assessing the selfpurification process with distances downstream in the dry season period for the water body of Qalyasan stream in
Sulaimani city. Since, pollution load in Qalyasan stream increases continuously due to effluent discharge by means of
many small and large scale industries, agricultural, domestic waste etc. WQI was calculated on the basis of Weighted
Arithmetic Index by analyzing 8 to 9 physico-chemical parameters; the calculation of WQI was conducted twice, with
and without the input of dissolved oxygen parameter, in case of including DO input, 2 mg L-1 DO was assigned as a
standard limit. To determine WQI degree for agriculture and the self-purification capacity of the stream, water samples
were collected four times from 1st July to 18th August, 2013 at 3 different sites of 6 km stretch. The results showed that
the values of the investigated physico-chemical properties at these sites were mostly in permissible limits of WHO and
FAO guidelines. Furthermore, the mean values of WQI were in a decreasing trend from S1 to S2 and then from S2 to
S3 (S1> S2> S3). This condition proofed that Qalyasan stream had the potential capacity or ability for natural self
purification and clean up the water pollutant through the natural process and also indicated that the water quality of
Qalyasan stream was still suitable for irrigation and livestock drinking with regarding the investigated physico-chemical
parameters and along the investigated stretch. Although no remarkable differences were noted between WQI values for
the case of included and non-included DO input parameter, the multiple comparisons tests by standard deviation (SD)
revealed that DO is an important input parameter for calculating WQI.

Khwakaram, A.I., Majid, S.N., Ahmed, Z.H. and Hama, N.Y., 2015. Application of Water Quality Index (WQI) as a possible indicator for agriculture purpose and assessing the ability of self purification process by Qalyasan Stream in Sulaimani City Iraqi Kurdistan Region (IKR). International Journal of plant, animal and environmental Sciences, 5(1), pp.162-173.