Urban Drainage Flashcards
Whys is infiltration low and surface runoff high in urban areas?
> Urban areas are covered in impermeable materials e.g. concrete and tarmac.
This means that infiltration is low in urban areas, so replenishment of groundwater stores is slow. Groundwater feeds rivers, so during drier periods, river discharge in urban areas is low.
> Precipitation is higher in urban areas and stores are more intense- this increases surface runoff.
> Runoff is channelled through man-made pipes, which transport water to rivers and streams.
Important:
> Low infiltration rates and high surface runoff and channelling of water mean that water enters rivers quickly. This gives short lag time and high peak discharge, with a fast return to base flow.
What is Catchment management?
Catchment managerment is a way of managing rivers and improving drainage systems by looking at the whole river catchment, an the intertactionsbetween water and land.
