EVALUATION OF WATER QUALITY OF DIYALA RIVER FOR IRRIGATION PURPOSES

Abstract

The study comprised suitability evaluation water of quality of Diyala riverfor irrigation uses. Four stations were selected along Diyala river which are Jalawlah station(DI2) before Jalawlah Bridge, Saadiyah station (DI3) before inter to Hamren Dam, Muqdadiastation (DI4) after Diyala Dam, and Baqubah station (DI5) at Iron Bridge, besides wand riverstation in Khanaqin (DIW) Before Dam. Water samples were collected and analyzed for pH,electric conductivity (EC), TDS, Na+, K+, Ca2+, Mg2+, HCO3-, CO32-, SO42-, Cl-, and NO3- onesample monthly were taken from these stations during January to December 2010. Inaddition, to classifying water quality and evaluation its suitability for irrigation purposes,Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP) and Residual SodiumCarbonate (RSC) were calculated following standard equations and found experimentally as(0.985), (20.027), (-4.404) respectively. According to the EC and SAR plotted on the USsalinity diagram, it is illustrated that water samples of DIW and DI5 fall in the class of C3-S1indicating high salinity with low sodium water, which can be used for irrigation on almost alltypes of soil with only a minimum risk of exchangeable sodium, while water samples of otherstations fall in the class of C2-S1 indicating medium salinity with low sodium water, whichcan be suitable to salt tolerant plants with probability developed permeability problem of soilwhen Lime is not existing. RSC values are negative at all sampling sites, indicating that thereis no complete precipitation of calcium and magnesium. All other parameters were withinstandard levels. The results of the study revealed that the quality of Diyala river water can beclassified as suitable for irrigation with few exceptions.