Organize And restore Closad super saline estuaries, nimerical modeling

Petrochemical Special Economic Zone is located in khuzestan province the southwest of Iran. The area of the PSEZ is about 2000 Ha. Jafari and Zangi esturies, closed esturies have a high concentration of salinity due to the closure of its mouth in three decades ago. This water body is salinity saturated and its salinity is about seven times of the salinity in the Persian Gulf. In addition to that, geotechnical surveys has shown that there are about 1.5 up to 3 meters of salt deposit in the bottom of these estuaries and volume of this depositions are about 6 milion cubic meters. In order to organize, restore these estuaries and improve environmental situations, it has been decided to improve the water quality by reducing the salt concentration both in the water column and the bottom. Different scenarions were proposed to achieve this goal. MIKE 11 was used initially as the numerical tool to evaluat the performance of different scenarios. However, MIKE 11 and other commerical numerical models are not able to simulate the release of salt from the bottom deposits when the salinty of the water cilumn becomes less than saturated level. Therefore an empirical mass transport equation were involved and combined with the abilities of MIKE AA to consider the salt deposits as a source of salt. In this paper a trial and error methods based on law used to estimate the release rate of bottom salt is described and results obtained from the numerical simulation are presented. It will be shown that the required time for reducing the salinity in the closed estuaries to the natural level would be about 5 and 2 years for Zangi'sand Jafari's closed estuares, respectively. It should be noted that field measurements need to improve the predictions. However this measurements need to be carried out after installing the culvert.