Assessment of sea water intrusion under climate change and future sea level rise scenarios in Kadhan Pateji Outfall Drain (KPOD) of Badin district, Sindh, Pakistan | |
| Author | Karim, Sanwal |
| Call Number | AIT Thesis no.WM-19-40 |
| Subject(s) | Hydrodynamic models Climatic changes--Pakistan--Badin District Sea level--Environmental aspects--Pakistan--Badin District |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Water Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | This research is assessing seawater intrusion and salinity variations in the lower part of Kadhan Pateji Outfall Drain (KPOD) by using mathematical modelling. In this study, MIKE 11 model was used which includes the application of hydrodynamic and advection-dispersion model in order to examine salinity problems as a result of climate change and under the influence of sea level rise and different flow regimes. This study also recommends alternative measures to manage salinity problem in the study area for future. In order to investigate the amount of saltwater in the current situation, the data observed from 2018 to 2019 were used for simulations and in connection with future changes, water levels were generated by the IPCC AR4 sea level model under SRA2, SRB1 and upstream discharge estimated using RCM data; ACCESS and CNRM CM under RCP 4.5 and RCP 8.5 for 2030 as the near future and 2050 as the mid future. The model was setup with upstream discharge (2015-2019) provided by Sindh Irrigation Department and downstream boundary was provided by downscaled hourly tidal elevations. The calibration and validation of the model was based on observed data and primary data collected from Irrigation Department of Sindh. The simulation results of the baseline year showed that the salinity from the sea intruding about14 km from the mouth of the river, and this 14 km range was divided into four stations to analyze the concentration of salinity. The maximum salinity concentration observed is 40.4 ppt at Station1 (9.3km from river mouth), 32.1ppt at Station2 (10.8 km from river mouth), 23.9 ppt at Station3 (12.4 km from river mouth), and 19 ppt at Station4 (13.8 km from river mouth) respectively. Comparing with future simulations, the effects of the present condition were used to assess an increase or decrease in salinity concentration under various flow regimes. This revealed that in near future, salinity will be increased between 7 to 40% and 12 to 68% in mid future respectively under different climate change and sea level rise scenarios. The model provided insight into the effect of future changes in river flows and sea level rise on the intrusion of saltwater and thus the formulation of alternative measures. A broad crested weir was used in the model and placed at 1 km up from the downstream boundary. The model was simulated under three different scenarios, scenario 1 is the base scenario obtained from future climate change and sea level rise simulations, scenario 2 is simulations from scenarios 1 which includes weir (0.4123m high) as salt barrier, scenarios 3 is assuming fresh water upstream in scenario 2. A broad crested weir found very efficient alternative in order to manage salinity problem in future. The results showed that salinity intrusion from sea is fully controlled at station 4, partially controlled at station 2 and 3 while at station 1, it controls about 30% as it is very near to canal mouth. |
| Year | 2019 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Shanmugam, Mohana Sundaram; |
| Examination Committee(s) | Shrestha, Sangam;Roa, Arturo Gementiza; |
| Scholarship Donor(s) | Irrigation Department, Government of Sindh, Pakistan; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2019 |