OUESTION $6(25$ MARKS$)$

a$)$ Explain the need for a proper drainage system on a road, clearly stating its functions. $5$marks

b$)$ Describe the types of drainage systems, clearly stating the different elements forming up the drainage systems. $10$ marks

c$)$ Describe the major factors considered when estimating design floods in preparation for drainage design. $5$ marks

d$)$ Explain any one method you would use to estimate surface runoff. $5$ marks