Free Flow

[

] 280

conomic

evelopment

and

ater

socioeconomic status of the household. In addition to

these household consumption patterns, an integrated

framework must capture the consumption from yard

taps, private wells, water kiosks and private water

vendors. It must also account for a variety of differ-

ent on-site and off-site sanitation options such as pit

latrines, septic tanks and the (often missing) waste-

water treatment. The major impact poor sanitation

has on the pollution of potential water sources must

also be accounted for. In most African cities adequate

water treatment is provided at the treatment plant, but

the potable water is contaminated in the distribution

system. Intermittent supplies and low pressures encour-

age stagnancy and the entry of contaminants which

deteriorate the microbiological water quality, resulting

A water framework for African cities

IUWM contextualizes the water sources, water supply, wastewa-

ter and stormwater within an integrated urban water framework in

order to understand the dynamic interactions between the various

components of the urban water system. Unfortunately, most exist-

ing integrated frameworks, such as Urban Volume and Quality,

Aquacycle or CityWaterBalance, are designed for the conditions of

cities in developed countries, neglecting the specific challenges of

cities in sub-Saharan Africa. Hence there is a need for an urban water

framework specifically designed for the cities in sub-Saharan Africa.

An integrated framework designed for African cities has to

consider a number of water and sanitation practices characteristic

of African cities. Water consumption conditions include the huge

disparity of water consumption, ranging from 40 to 255 litres per

person per day, depending on the type of service provision and the

Groundwater

Surface water

Receiving water

Rainwater

Evapotranspiration

Water

supply

Roof

Surface

Runoff

storage

Kitchen

laundry and

bathroom

Toilet

Irrigation

Pit latrine

Septic

tanks

Rainwater harvesting

Leakage

Public tab

Yard tab

Conventional HH

connection

Wastewater

recycle

Exfiltration

Sewer

Infiltration

Overflow

Inflow

Recharge/infiltration

Subsurface flow

Cross

contamination

Stormwater

collection

Cascading

Greywater

reuse

A tailored integrated urban water framework for cities in sub-Saharan Africa

Source: Vairavamoorthy et al, 2012