Highway drainage system

This document discusses highway drainage systems. It defines highway drainage as removing surplus water within highway limits and disposing of it. There are two main types of drainage systems - surface drainage and subsurface drainage. Surface drainage collects and removes surface water using methods like ditches, inlets, storm sewers and culverts. Subsurface drainage prevents changes in soil moisture levels using underground drains to intercept groundwater and seepage. Proper drainage is important for preventing issues like erosion, pavement damage and reducing the soil's bearing capacity.