Evaluation of the Effect of Detailed Implementation Project of the Dokhtar Borji Watershed, Andimeshk County, with an Emphasis on the Successful Experience of Roller Compacted Concrete Dams for the First Time in Iran's Watershed Management

The present study was conducted to analyze the detailed implementation project of the Dokhtar Borji Watershed where located at the upstream of Karkheh Dam. To this end, the results of calculating of study environmental variables at before project implementation including physiography, climate, hydrology, lithology, groundwater, pedology, vegetation, socio-economic, erosion and sediment was considered. Thence, via comparing these results with results of calculating of study environmental variables after project implementation, the effect evaluation on the environmental of two study units was done. The erosion of the area is estimated between 17 and 21 t ha-1. Erodible formation of Lahbary and quaternary sediments in the study watershed entering a high percentage of eroded soil into the reservoir of Karkheh Dam. Therefore, these conditions insisted the managers of the watershed to implement different operations in accordance with the natural conditions of the region. The carried out operations were included biological activities viz., transplanting, seeding and pit- seeding and the check dam construction with types of bag, bag-gabion, dry-stone, gabion and roller compacted concrete (RCC). According to anecdotal observations and project assessment, 80 % of the cultivated species have been established, and due to the failure to application of the technical principles of planting, the lack of high quality species, the lack of stacking in high slopes, the presence of pests and inappropriate irrigations, 20 % of adapted seedlings have not been established. A comparative study on the performance of check dams in sediment controlling with RCC dams showed that the mentioned dams were successful and could play an important role in sedimentation mitigation.