An application for a coastal waters discharge permit to discharge effluent into an estuary may only be granted in exceptional circumstances, and only where it is demonstrated that-
(a) such inflows are required to improve or will maintain any applicable resource quality objectives;
(b) such inflows will improve the general ecological state of the estuarine system;
(c) such inflows will not deteriorate the ecological state of the estuarine system; or
(d) the ecological functioning of the estuary has been irreversibly modified in an adverse manner, and the discharge will not lead to a further deterioration of the water quality in the estuary.