The spatio-temporal variability of river processes is governed by the balance between basin scale sediment supply and channel transport capacity. This balance is being altered by rampant sediment mining from the rivers which results in channel alteration and loss of physical habitat. The sediment mining guidelines are mostly based on empirical approaches and do not consider the spatio-temporal variability of river processes. This study includes hydrologic and geomorphic analysis to understand sediment dynamics and to suggest guidelines for sediment mining. The study was carried out in the 1312 km long Narmada River basin, Central India using hydrological data (1987-2015), SRTM DEM and LULC data. We identified the major aggrading river reaches (100s of km long) on the basis of reach scale sediment mass balance analysis. These reaches are dominantly aggrading at the rate of ~50,000 tons/km/yr. Sediment yield values were used to identify major erosion hot spots in the river basin and its contribution to spatial variability in aggradation-degradation processes in the river channel. This spatial variability within channel was also ascertained through stream power and sediment supply relationship. Further, temporal variability in channel processes was observed in the aggrading reaches. This variability is mostly governed by sediment concentration. Higher sediment concentration (~1.5 g/l) in a given month may change degrading reaches into aggrading reaches. Spatial variability within aggrading reaches and sediment contribution from different sub-basins was further assessed through application of semi-distributed process based Soil and Water Assessment Tool (SWAT). SWAT-CUP yielded good calibration results (~ 40% of the measured data bracketed under the 95PPU envelope, for discharge and sediment load). SWAT was found to be suitable to analyze sediment yield distribution at HRU scale in the Narmada River basin, except for smaller and steeper subbasins where hillslope processes dominate. Further, spatial variability within these reaches was identified by analysis of bar dynamics. Satellite data based change detection analysis was used to identify aggrading channel bars. These bars may be focused for sand mining operations within the aggrading reaches, although limited to ~20% change in the sediment bar area.