The dams in and around Cape Town form part of the Western Cape Water Supply System, which is an integrated and collectively managed system of dams, pump stations, pipelines, and tunnels. In addition to servicing Cape Town, the system supplies water to towns in the Overberg, Boland, West Coast, and Swartland areas, and provides irrigation water for agriculture. The change in depth of the Steenbras dam from one day to the next, measured (in feet) at in Cape Town, is a random variable ? with the following density function:

f( y) 2