text: An auxiliary bridge allows armourstone to be directly deposited into the closing gap. This method was contemplated for the Delta Works' Oesterdam closure but was ultimately deemed more expensive than sand closure. In the Netherlands, such a technique was applied during the closure of the dike around De Biesbosch polder in 1926, where a temporary bridge facilitated the dumping of materials into the gap using tipping carts propelled by a steam locomotive.