Rule 37 "Beach" recontouring
https://archive.gw.govt.nz/Rule-37-Beach-recontouring
The disturbance and recontouring of any part of the bed of any river that is not covered by water (i.e., beach recontouring) to remedy or mitigate the adverse effects of flooding or erosion is a permitted activity, provided that the activity complies with the conditions below.
Conditions
(1) The river or lake bed shall not be disturbed to a depth or an extent greater than that required to reduce the flood or erosion hazard to an acceptable level.
(2) The material shall not be mounded up so that it forms a barrier to water movement.
(3) No contaminants (including but not limited to oil, petrol, diesel, paint, or solvent) shall be released onto the bed from equipment being used for the operation, and no refuelling of equipment shall take place on any area of river or lake bed.
(4) There shall be no machinery within the area of river bed covered by water while the operation is in progress.
(5) There shall be no disturbance to nesting Banded Dotterels (Charadrius bicinctus), Black Fronted Dotterels (Charadrius melanops), Black Billed Gulls (Larus bulleri), Pied Stilts (Himantopus leucocephalus),or Variable Oystercatchers (Haematopus unicolor), South Island Pied Oystercatcher (Haematopus ostralegus), Caspian Terns (Sterna caspia), White-Fronted Terns (Sterna striata), and Spur-Winged Plover (Vanellus miles).