Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Paper format. National Examination, May 2019 — 16-Civ-B5 Water Supply and Wastewater Engineering. Three hours; closed book with one aid sheet written on both sides; an approved Casio or Sharp calculator is permitted. Question 1 is compulsory and candidates attempt any three of Questions 2 to 5, so 100 marks are on offer from a 125-mark set. Marks are shown at the end of each question, and the paper states that clarity and organisation of answers are important. Because the set is a study resource rather than a sitting, all five questions are solved here.
Reference texts.
Check: page 1 of the paper carries the header 16-Civ-B5-May 2019 - Page 1 of 3 and the title NATIONAL EXAMINATION, MAY 2019, so this is the May 2019 sitting. Where the exam says "make suitable assumptions", every assumed value is stated explicitly at the point of use.