design sanitary sewers.

$($use map given and set up arbitrary distance and length of street. $)$

use arbitrary values during designing if it is needed.

GIven Conditions:

the future avarage saturation population density is estimated $50$person$/$ha

the average flowrate of residential waste water is estimated $400$Lpce.

peak ww flow $,$ maxrate of Gw infiltration $->$ use arbitrary value.

$2,$

min soze of sewer pipe is $300$mm

min velocity of flow in sewer when full is $0\mathrm{.}7$m$/$s

but $0\mathrm{.}85$m$/$s is more desirable

the wall thickness of the $200$mm pp is $20$mm

Use mannings equation n$=0\mathrm{.}013$

the min depth below the street surface to the top of the sewera is $2\mathrm{.}5$m