ESDA Sustainable Development Workshop Series
River pollution, flood inundation and health
risk nexus: Towards improving urban water
environment
Dr. Binaya Kumar Mishra,
United Nations University, Tokyo
UNU-IAS
MISSION
Advance efforts towards a more sustainable future,
through policy-relevant research &
capacity
development on sustainability
THEMATIC AREAS
1.Transformations toward Sustainable Societies (TSS)
2.Natural Capital & Biodiversity (NCB)
3.Global Change & Resilience (GCR)
UNU-IAS Research programs
Transformations toward
Sustainable Society (TSS)
Natural Capital &
Biodiversity (NCB)
Global Change &
Resilience (GCR)
GSD
ISI
UN-CECAR
ESD
ESA
CECAR-Africa
ESDA
AFS
POPs
FGC
BIO
GPSS-GLI
WUI
GEOC
ESDA: Education for Sustainable Development in Africa
WUI: Water and Urban Initiative
Urbanization and Water
Rapid development of urban area
-Increased commercial water demand, Decreased green open
space, Decreased groundwater recharge, Increased flooding
 Increase of population
-Increased domestic water use
 Change of lifestyle
-Increased wastewater treatment
 Inadequate wastewater treatment
-Deterioration of water environment
 Excessive groundwater extraction
-Decreased lean season flow, land subsidence

Climate change and urban growth
Comparison of 50-yr daily maximum rainfall over different cities using
MRI-CGCM3.2, MIROC5 and HadGEM2-ES models; and RCP4.5 and
RCP 8.5 emission scenarios
50-yr rainfall (mm)
Increase (%)
Current
Future (extreme)
Hanoi
335
410
22
Manila
357
451
26
Jakarta
228
330
45
Medan
178
253
42
Chennai
328
378
15
Lucknow
195
300
53
Cities
•Use of multiple GCM and emission
scenarios due to large uncertainty in
climate projections is important
• Climate projections revealed an increase
of 15 to 53% in daily maximum rainfall
•Climate change consideration in urban
drainage plans is of greater significance
Landuse land cover projection using Land Change Modeler
Cities
Hanoi
Jakarta
Manila
Lucknow
Chennai
Medan
Urban area (Km2)
Current
Future
67
72
148
210
224
249
39
48
40
59
113
121
Increase
7%
42%
11%
22%
47%
6%
Built-up area is projected to increase by 6
to 47 % over the study cities which can
significantly alter the stormwater runoff
pattern
deteoriating
urban
water
environment.
River Pollution


Point source
Non-Point source
Polluted urban rivers
Urban floods
• Large-scale inundation events (e.g., Manila, Hanoi, Chennai, Jakarta) local pockets of
water logging (e.g., Lucknow, Kathmandu) are regularly reported in rapidly growing
cities in Asia resulting traffic disruption, heavy tangential and non-tangential damages.
• Reduction of retention and retarding functions due to increased impervious surface,
losses in ponds; increased extreme rainfall events due to climate change; inadequate river
flow capacity due to encroachment are largely attributed to increasing urban flood
incidences
Inundation in Chennai, India (2015)
Waterlogging in Lucknow, India (2017)
7
Health nexus
Exposure to contaminated flood water in urban areas can pose a
significant human health risk. Health conditions of people living in
flooded areas can become compromised due to exposure to
pathogens contaminated water. In such urban environments, the
potential for disaster is great and countermeasures are urgently
needed.
Total burden of disease are the waterborne and water-related diseases. These
often have a seasonal character based
upon the weather patterns and also
affect whole communities at the same
time. We find direct relation between
urban floods and dengue & diarrhea.
Correlation between flood and water-related disease patients in West Java
(Source: https://www.floodtags.com/830/)
Water and Urban Initiative (WUI)
9
WUI: Target cities
10
Projecting Future of Urban Water
Reports/publications
• Full report and Summary for Decision Makers
• Available at:
http://www.water-urban.org/
Model development: river pollution
WEAP (Water Evaluation And Planning) model is a highly
flexible hydrologic-water quality model
Study Definition
Spatial Boundary
Time Horizon
System Components
Network Configuration
Current Accounts
Demand
Reservoir Characteristics
River Simulation
Pollutant Generation
Resources and Supplies
Wastewater Treatment
Scenarios
Demographic and Economic Activity
Patterns of Water Use, Pollution Generation
Water System Infrastructure
Hydropower
Allocation, Pricing and Environmental Policy
Component Costs
Hydrology
Evaluation
Water Sufficiency
Pollutant Loadings
Ecosystem Requirements
Sensitivity Analysis
Model development: flood inundation
• Hydrologic-hydraulic modeling
• Climate change projections downscaling
• Land use land cover projection
• Scenarios development in 2030
Study areas
-To Lich River in Hanoi (~112 km2)
-Ciliwung River in Jakarta (~230 km2)
-Deli River in Medan (~240 km2)
-Marikina-Pasig-San Juan River in
Manila(401 km2)
-Adyar River in Chennai (~65 km2)
-Kukrail River in Lucknow (~60 km2)
Urban flood
Framework for hydrologic-hydraulic simulation
Model development: Health risk
Characterize and quantify the human health risks
associated with exposures to pathogen present in the
flood water.
Case study: Manila
Marikina-Pasig-San Juan River system
Inundation modeling area 401 Km 2
Inundation modeling area 334 Km2
16
Comparison of flood inundations (moderate scenario)
Current climate
Climate change ( moderate)
CC (moderate)+
countermeasures
Countermeasures: dam (75 MCM), greater flow capacity (600 to 1200 m3/s
of Pasig river), infiltration measures and flood canal diversion (with full
capacity 2400 m3/s instead of 1600 m3/s
17
Comparison of flood inundations (extreme scenario)
Current climate
Climate change ( moderate)
CC (moderate)+
countermeasures
18
Flood simulation
Flood hazard (> 1.5 m)
Inundation area (km2)
% change
Current
CC Extreme
39.12
83.41
113%
CC
CC (Moderate) CC (moderate)+ measures
(extreme)+measures
33.28
76.07
20.8
-15%
94%
-47%
River pollution (without measures): Comparison
BOD (mg/L)
200
2015
150
100
50
2030
NO3 (mg/L)
Simulated Water quality (considering population growth and average climate change and WWTP of 65 MLD capacity
16
(without master plan)
14
12
10
8
6
4
2
0
2015
2030
Upstream
Napindan/C6
Bambang Bridge
Guadalupe Ferry
Lambingan Bridge
Nagtahan Bridge
Jones Bridge
Manila Bay
0
Downstream
Location
Location
E.Coli (CFU/100ml)
1000000000
100000000
2015
10000000
1000000
2030
Black bar showing the range of values observed
with change in GCM and RCP.
GCM considered- MIROC, MRI
RCP considered- RCP4.5, RCP8.5
100000
10000
Parameters
1000
Unit
100
10
1
Location
Fishable
(Class C)
Swimmable
(Class B)
BOD
mg/L
7
5
E.Coli. (*Fecal
Coliform)
MPN/1
00ml
200
100
NO3
mg/L
7
7
Philippine water quality (DENR, 2016)
20
River pollution (with measures): Comparison
NO3 (mg/L)
BOD (mg/L)
Simulated Water quality (considering population growth and climate change (MIROC5, RCP 8.5)) (Extreme condition)
and WWTP of 612 MLD capacity (with master plan)
200
16
14
2015
2030
2015
2030
150
12
10
8
100
6
4
50
2
0
0
Upstream
Napindan/C6
Bambang Bridge
Guadalupe Ferry
Lambingan Bridge
Nagtahan Bridge
Jones Bridge
Manila Bay
Downstream
Location
Location
1000000000
E.Coli (CFU/100ml)
100000000
2015
2030
10000000
1000000
100000
10000
1000
100
Black bar showing the range of values observed
with change in GCM and RCP.
GCM considered- MIROC, MRI
RCP considered- RCP4.5, RCP8.5
*here value of chlorination is not considered
10
1
Location
21
Current and future floodwater-borne norovirus infections
2015 estimates
Total number of illness: 1,007
2030 estimates without mitigation
Total number of illness: 2,528
Current and future floodwater-borne norovirus infections
2030 estimates without mitigation
Total number of illness: 2,528
2030 estimates with mitigation
(560 MLD WWTP + large dam)
Total number of illness: 23
Conclusions/Recommendations (flood)
•In overall, the study found that combinations of countermeasures (dam, can reduce
additional inundation caused by climate change. Optimization is important.
•Pumping of flood water could be better alternative in reducing low land region
inundation.
•Although the flood control measures such as river improvement, diversion channel and
dam construction can have high effects on the flood control, these might take long time
for completion, and require a huge investment.
•Thus, in order to realize the flood mitigation effect urgently, it is important to promote
non-structural measures (runoff control measures) such as installation of rainwater
storage and infiltration facility, conservation and rehabilitation of pond (Situ), and others.
•Non-structural measures, which consist of land use regulation for the preservation of
retention and retarding functions and disaster mitigation measures such as preparation of
flood hazard/damage map, improvement of disaster information system and others will
also contribute to the water resources conservation and groundwater recharge as well.
24
Conclusion/recommendations (river pollution)
 WEAP model can be applied to simulate various water quality management
strategies to maintain stated water quality criteria.
 After incorporating master plan with WWTP capacity of 612 MLD in water
quality simulation, it is observed that quality will improve significantly by year
2030 an encouraging sign.
 However looking into water quality guidelines by DENR (2016), many of the
location especially along the downstream don’t comply for Class B
Swimmable.
Parameter
Average % increase
(2015 to 2030)
% Contribution
from Population
growth
% Contribution
from climate
change
BOD
79
67
12
E.Coli.
112
86
16
NO3
49
41
8
Table – Brief summary of result
25
Summary and recommendations (Health)
◦ Without any measures, risk of infectious gastro-intestinalis spread via flood
water will increase (+151%) because of severe water quality deterioration and
population increase.
◦ It is likely that the risk can be significantly reduced by completing master plans
on wastewater treatment and flood management (dams, etc.).
◦ Raise public awareness: avoid contacting flood water, distribute solid soap to
residents in affected areas
26
Thank you very much!