In recent year, climate change and its impact have become a real and urgent global problem . Mekong Delta is one of the three deltas in the world which is most vulnerable to climate change. The increase of temperature leads to the increase evaporation and the dry season starts earlier and finishes later than before. In the dry season, flow in the river decreases especially in March and April, follows with this is salinity intrusion to inner area of Mekong Delta . A large area of agricultural land was lost due to saline water and significantly reduced crop yield leads to the decrease in water and la nd productivity in Mekong Delta in general and Long Xuyen Quadrangle in parti cular. Although there many studies related to impact of climate change to salinity in Mekong Delta but research fo cus on Long Xuyen Quadrangle still does not provide enough inform ation for adaptation with salinity. It is necessary to have a detail analysis about the impact of climate change to salinity and then salinity intrusion on crop yield. This study uses MIKE 11 both HD and AD module to simulate for salinity intrusion at cur rent situation in 2008, 2004 and future scenario in 2020, 2030 and 2050. The result describes the change in area impacted by saline water and level of salinity concentration in whole area. BUDGET is a model which helps understand the impact of saline irrig ation water on crop yield gives the result ing of yield reduction. From the output of MIKE 11 and BUDGET, scenarios for enhanced and sustained rice production under the influence of saline water in 2020 have been studied herein.

A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Engineering in Water Engineering and Management at the Asian Institute of Technology And The degree of Master of Science at the UNESCO - IHE, School of Engineering and Technology

Thesis (M. Sc.) - Asian Institute of Technology - UNESCO-IHE, 2012