Key Messages 
Several options can be used to ensure stable conditions for inland water transport, especially a stable river-bed. For example, river groynes are rigid hydraulic structures built from an ocean shore (in coastal engineering) or from a bank (in rivers) that interrupt water flow, limits the movement of sediment and protects coastal areas or river banks. The option can protect against flood, but also droughts. Furthermore, ship design can be adjusted to low water levels, e.g. with smaller ships, different material.