Section 10 of the Water Act 54 of 1956 does not contain an express or implied requirement that surplus water must be used only on riparian land, unlike section 9(1) which expressly limits normal flow to use on riparian land. The express inclusion of a territorial limitation in section 9(1) and its absence from section 10 indicates legislative intention not to impose such a limitation on surplus water use. Section 9B(1) of the 1956 Act prohibits only the construction, alteration, or enlargement of waterworks above specified capacities without a ministerial permit, not the operation of existing waterworks constructed before the provision came into force. Section 40(1) of the National Water Act refers to statutory requirements to obtain a license, not ad hoc demands by officials. A person with existing lawful water use under section 32 may continue such use until formally required by competent statutory authority to apply for a license. Administrative directives issued under section 53(1) of the National Water Act must be based on correct legal principles and are reviewable where they result from application of wrong legal principles, failure to apply mind, consideration of irrelevant factors, or unreasonableness.