Investigating effects of mining on sedimentary properties of Lisar River (Guilan Province, Iran) using HEC_RAS model

Increasing land development projects lead to demand for riverine mining, followed by erosion and deposition. The aim of the research was to assess the sedimentary impacts of mining activities on the Lisar River. The research material comprised environmental, hydraulic, and sedimentary information, mining history, and dimensions. Detailed topographic and TIN maps, and 55 cross-sections of the Lisar River mining, were prepared. This study simulates flow patterns in a quasi-unsteady condition and sediment transport capacity using the HEC-RAS model. The maximum change along the longitudinal profile of the river mining is 3 m. The spatial map of the mining in different river sections was determined based on the maximum allowable depth of mining. The present research recommends the Yang function use in simulations of the rivers with sandy-gravel texture accompanied with or without riverine mining and steep slope. Results indicate the current mining volume is up to three times the allowed capacity for the extraction from the Lisar River. The present research concluded that the management plan for spatial mining and measures for monitoring based on the spatial distribution of depositional and erosional sites is necessary for this and other such areas to conserve natural resources.