This is an overview of a flume at caltech where a long narrow section flows into a large ocean basin. Here, we build deltas with subcritical flow and backwater lengths of ~1m. Sediment & water feed rates are precisely controlled at the upstream end of the narrow section such as to build a normal flow reach in the river section with a specific depth (~1cm) & slope (~3e-3). Bedload transport is maintained under these conditions using sand-sized (0.7mm) walnut shells. Water level in the basin is controlled with an adjustable weir at the far downstream end of the basin.