CITY SCALE - HYDROLOGY Land subsidence

Resource: https://www.bbc.com/news/world-asia-44636934

Pollution

Water sewerage system

Only 4% of Jakarta has access to sewerage, with 96% or over 9.2 million people, with no wastewater management or treatment systems.

Water quality

Spatial distribution of Jakarta water quality A) Average value of BOD; B) Trend Z value of BOD; C) Average value of DO; D) Trend Z value of DO; E) Average value of TSS; F) Trend Z value of TSS during the studying period.

BOD: Biological Oxygen Demand

Upper stream: low average values of BOD

Downstream and middle stream: high average values of BOD

DO:Dissolved oxygen

The average value of DO decreased from upstream to downstream

The central district showing high DO values

-REASON: the result of rapid urbanization in Jakarta which increased housing development in the upper and middle streams.

TSS: Total suspended solids

Most stations have low average values of TSS

The central and eastern districts that have high average values of TSS.

-REASON: result from construction and wastewater due to high population density and urbanization.

Quality standard of water in Singapore

Items of Analysis range

BOD <10 mg L-1

Dissolved oxygen >2mg L-1

Total Suspended Solids <200 mg L-1

RED CIRCLE means this station meets the standard value of Singapore. BOD: Only few of the water catchment meet the standard of BOD (<10 mg L-1).

DO: About half of the stations’ water quality of DO higher than 2 mg L-1

TSS: Only two station have high level of TSS (larger than 200 mg L-1)

Source: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0219009