Evaluation and development of Shatt Al-Diwaniya and the diversion canal of Shatt Al-Diwaniya

Abstract Shatt Al-Diwaniya branches from Shatt Al-Hilla and extends for about 112 km until the Al-Rumaitha district within the study area located in Al-Diwaniya Governorate, Iraq. It is considered the main source for providing drinking water and supplying irrigation projects to the cities Al-Diwaniya and Al-Rumaitha. The study aims to evaluate, study, and develop Shatt Al-Diwaniya, as well as the new lined canal branching from Shatt Al-Diwaniya which. It is called Shatt Al-Diwaniya Diversion Canal. Field measurements of the discharge and water level were monitored, six sets for Shatt Al-Diwaniya and three sets for Diversion Canal. A one-dimensional model was developed by using HEC-RAS 5.0.7 software, the model was calibrated and verified according to the field measurements, the Manning’s coefficient (n) of Shatt Al-Diwaniya, and the Diversion Canal is 0.023 and 0.018, respectively. Five Scenarios were simulated to study the reach under the current conditions. it was found the discharge capacity in Shatt Al-Diwaniya is 60 m3/s and the Diversion canal is 22 m3/s. Other additional six scenarios were conducted for the modification of the reach included several cases, firstly, the development of Shatt Al-Diwaniya only, secondly, the development of the Diversion Canal only, as well as the development of the Shatt Al-Diwaniya with the development of Diversion. The results of development show that Shatt Al-Diwaniya can reach design discharge 96.2 m3/s, and for the Diversion will pass the maximum discharge 45.5 m3/s.