obelisk for dutch sluice dokkumer nieuwe zijlen

architectural architecture arms ball balls building civil coat complex connect connecting construction control controlling decorated decoration dokkumer dokkumerdiep drainage dutch engineer engineering europe european floodgate friesland frisian gilded grootdiep holland honor infrastructure landmark lauwersmeer level lock memorial monument natural nature needle netherlands new nieuwe obelisk outdoor outdoors outside pedestal protect protecting rising safe safety separate separating sluice surface technique technology tidal tide water waterlevel watermanagement waterwork waterworks weir wet zijlen