This section applies where it appears to the appropriate agency that—
For the purposes of this section the condition of a hydromorphological quality element affecting the controlled waters is unsatisfactory if (whether by itself or in combination with other factors) if it is likely to prevent the waters from achieving the applicable environmental objectives.
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The appropriate agency shall be entitled to carry out works and operations for the purpose of improving the condition of the hydromorphological quality element in question with a view to achieving (or contributing to the achievement of) the applicable environmental objectives.
The appropriate agency shall be entitled to carry out investigations for the purpose of establishing why the condition of the hydromorphological quality element in question is unsatisfactory.
Without prejudice to the power of the appropriate agency to carry out those investigations, the powers conferred by subsection (4) shall only be exercisable if it appears to the appropriate agency that it is unable to secure that the necessary works or operations are carried out by exercising its powers under section 161 or 161ZA or by serving a works notice on any responsible person.