عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Due to the important role of subsurface drainage in managing the ground water level, there are many researches focused on finding a new and more economic way to develop subsurface drainage technologies. Lack of proper drainage system in northern Iran has caused huge implantation of rice and it is impossible to have second implantation in this region. One reason of insufficiency of current drainage systems in this region might be the absence of envelope material like sand and gravel or in some cases the long transportation of gravel envelope materials to the project site which rises drainage cost. In this region, rice husk is considered as wastage of rice production. Production of rice husk is estimated to be 600 thousands tons every year in Iran, which can be potentially used in drainage systems. The main objective of this research is to investigate the feasibility of using rice husk instead of drain pipe and envelope materials. The performance of drainage system using rice husk was studied in a laboratory model and the obtained results were compared with the conventional gravel envelope materials in terms of their drainage capacity and reaction factor for water table drawdown. The maximum drainage discharge was measured to be 0.13 and 0.12 lit/s in the case of rice husk and envelope materials, respectively. The corresponding values for the reaction factor were estimated to be 8/937 and 9/899 day-1, respectively. The results also showed good functions of rice husk in decreasing water table and supporting the drainage needs.