The document discusses potential solutions for securing Ho Chi Minh City's water supply in the face of increasing salinity intrusion issues. It summarizes workshops that explored both short-term and long-term options. Short-term solutions included mixing water from alternative intake points with existing supplies or building small storage reservoirs. Long-term solutions involved larger infrastructure like canals, pipelines, or reservoir systems that could provide intake selectivity and storage capacity of 6-90 days to cope with salinity fluctuations. The workshops aimed to identify adaptive measures that balance water supply reliability, flood control, nature conservation and recreation.
3. CONTENTS
• Project outline and partners
• The Press
• SAWACO’s raw water sources and water
quality issues
• Lessons learned from the Netherlands
city of Rotterdam
• Objectives and approach of the workshop
• Solutions
• Immediate measures
• Short term solutions
• Long term solutions
• Adaptive pathways
7. SAWACO’S
2012 Measures to Adapt to Changes in Raw Water Resources
PASSIVE
• Reforestation of catchment areas
• Construction of a sea barrier
in the estuary of the Dong Nai / Nha Be river
• Control of industrial zone development
up- (and down-) stream of the raw water intakes
ACTIVE / PASSIVE
• Request to Tri An and/or Dau Tieng authorities to
flush the Dong Nai and/or Saigon rivers
ACTIVE
• Relocation of raw water intakes to the Tri An and Dau
Tieng reservoirs
• Application of new treatment technologies
• Construction of raw water storage reservoirs
9. WATER QUALITY | Saigon River – Hoa Phu Intake (2/2)
Chloride (mg/l) and Qflush from Dau Tieng Reservoir
0
5
10
15
20
25
30
35
0
100
200
300
400
500
600
700
1-1-16
0:00
8-1-16
0:00
15-1-16
0:00
22-1-16
0:00
29-1-16
0:00
5-2-16
0:00
12-2-16
0:00
19-2-16
0:00
26-2-16
0:00
4-3-16
0:00
11-3-16
0:00
18-3-16
0:00
25-3-16
0:00
1-4-16
0:00
QflushfromDauTieng(m3/s)
Chloride(mg/l)
Qflush from Dau Tieng Chloride at Hoa Phu Chloride 24 hour average
dry season 2016: January - April
Chloride Standard
10. PROBLEM SUMMARY
• Salinity intrusion is getting more severe;
• Flushing of the Saigon river with water from the Dau Tieng reservoir has proven not efficient, nor
effective in extreme situations;
• Production has been halted during periods when salinity intrusion is too high, putting the continuity of
public water supply in HCMC at risk, because clear water storage amounts to not more than half a day
production capacity;
• It will become increasingly precarious for SAWACO to rely on the Hoa Phu intake for raw water, hence
alternative raw water sources are to be identified for the treatment of water by the Tan Hiep WTPs
11.
12. ROTTERDAM DRINKING WATER SUPPLY
WTP Honingerdijk in 1923
1960s: Huge problems for Rotterdam’s drinking water supply
• Inferior water quality of the River Rhine due to heavy industrialization, and no
domestic, nor industrial sewage treatment
• Salinity intrusion in the winter of 1962-1963 due to extreme weather conditions
(January 22-28, 1963: brackish, undrinkable drinking water from the tap)
13. SOLUTION FOR ROTTERDAM
Moving Raw Water Intake and Building of Raw Water Storage Reservoirs in the Biesbosch
• Storage is necessary for
periods of low
discharge (River Meuse
is a rain-fed river)
• Intake stops are
possible in case of
inferior water quality
(seasonal, accidental or
intentional discharges,
or shipping accidents)
• Water quality improves
considerably during a
retention time of 5
months
De Gijster
Honderd-
en-Dertig
Petrus-
plaat
14. OBJECTIVES OF THE WORKSHOP
Intensive Brainstorming aimed at achieving the
highest degree of consensus possible on the
following topics:
• Short-term (low regret) solution for Tan Hiep
WTP: e.g. small raw water storage reservoir to
prevent interruptions of water treatment, as
recently experienced;
• Long-term water resources strategy and
solutions for SAWACO;
• Integral design of a possible (multi-functional)
water storage reservoir for Tan Hiep WTP:
Drinking water supply,
Urban flood control,
Nature conservation,
Recreation.
16. PRINCIPLES OF A
CHARRETTE
DESIGN WORKSHOP
• Intensive brainstorming
• Developing solutions
for problems with
spatial components
• Sharing ideas by
drawing
• Using different types of
base maps
• Field visits to study
areas
• Different groups
learning from each
other
17.
18. IMMEDIATE MEASURES
1. Revise raw water intake criterion for chloride: Stop
intake at 350 mg/l instead of at 250 mg/l. Because of
2:1 mixing with water of Kenh Dong WTP, chloride in
the clear water will remain below 250 mg/l.
2. Do not stop production when chloride in raw water is
> 250 mg/l, because this will have a negative impact
on the production process. After treatment,
discharge the water that does not comply with the
standard for chloride, even after mixing with water of
Kenh Dong WTP.
3. Reach an agreement with the regulator on what to
do in a situation when chloride in the to be
distributed clear water is > 250 mg/l. The advice is:
keep providing water as chloride is not a health-
related parameter, but an unpressured water
distribution would definitely constitute a public
health hazard.
19. Extend salinity monitoring
along the Saigon River
Develop an improved flushing policy
for Dau Tieng reservoir to counteract salinity
intrusion in the Saigon river
Carry out salinity modeling
of the Dong Nai / Sai Gon
estuary and lower river basin
IMPROVE
FORECASTING SALINITY LEVELS
AND FLUSHING POLICY
20. SHORT TERM SOLUTION
#1Use Lang The canal
1. Shift intake point upstream to conjunction of Saigon river
and Lang The waterway 11.5 km from Hoa Phu
2. Use existing waterways – 19 km – for raw water
transportation
3. Reroute existing streams that connect to the waterway
4. Build a controllable weir, allowing controlled flushing
of the waterway
5. Build intake works, pumps & 2 km pipeline to Tan Hiep
WTP with a capacity of 300,000 m3/d
6. Mix raw water from new upstream intake point with raw
water from Hoa Phu
1
2
4
5
6
3
21. SHORT TERM SOLUTION
#2Move Intake Upstream
1. Shift intake point upstream to Nang Am
14 km from Hoa Phu (along the Sai Gon river)
2. Build intake works, pumps & 13 km pipeline to Hoa Phu
with a capacity of 300,000 m3/d
3. Mix raw water from new upstream intake with raw water
from Hoa Phu
1
2
3
22. SHORT TERM SOLUTION
#3
Draw water from
Irrigation Canal N31A
1. Create a new intake point at the end of
irrigation canal N31A; available capacity at
this point is 3.5 m3/s
2. Build intake works, pumps & 9 km pipeline
to Hoa Phu with a capacity of 300,000 m3/d
3. Mix raw water from new intake with raw
water from Hoa Phu
4. Existing N31A canal may require
rehabilitation works
1 2
3
4
23. SHORT TERM SOLUTION
#4Mixing and Storage Reservoir
1. Build a mixing and small storage reservoir (1-2 days)
at ‘Duong Do Park (25 ha, ± 10m deep); location is close
to Tan Hiep WTP; area around the reservoir can be
developed for nature and/or ecotourism
2. Inflow: connect the existing raw water pipeline with the
reservoir
3. Outflow: build intake works, pumps & 1 km pipeline
to connect to existing raw water pipeline to Tan Hiep
WTP with a capacity of 600,000 m3/d
1
2
3
24. REFLECTION
ON SHORT TERM SOLUTIONS #1-4
0. Current situation 1. Use Lang The
canal
2. Move intake
upstream
3. Draw water from
irrigation canal
N31A
4. Mixing and small
storage reservoir
Mechanism to cope with
salinity intrusion
Flushing of water
from Dau Tieng
reservoir, selective
intake at Hoa Phu
Mixing water with
Hoa Phu water 1:1
Mixing water with
Hoa Phu water 1:1
Mixing water with
Hoa Phu water 1:1
Peak shaving by
mixing of the raw
water from Hoa Phu
Maximum chloride content
(mg/l) at Hoa Phu intake at
which production can
continue
300 ± 450* ± 450* 575 ±500-600
Investment estimate (±40%) - 16 M$ 30 M$ 24 M$ 30 M$
Realization period (±2Y) - 2 years 2 years 2 years 5 years
Multiple sources
for Tan Hiep
(redundancy, reliability)
No, only one intake
point from the
Saigon river at Hoa
Phu
Partly, two intake
points from the
Saigon river
Partly, two intake
points at Saigon
river
Yes, Saigon river
and Dau Tieng
reservoir
No, only one intake
point from the
Saigon River at Hoa
Phu
Main operational costs - - O&M intake,
pumping station,
canal and weir +
dams
- Pump energy
- O&M intake and
pumping station
- Pump energy
- Raw water price
per m3
- O&M intake and
pumping station
- Pump energy
- O&M intake,
reservoir and
pumping station
- Pump energy
*Assuming chloride at upstream intake point is 1/3 of chloride at Hoa Phu and mixing ratio Hoa Phu : upstream intake = 1:1
25.
26. LONG TERM SOLUTION
#1Green-Blue Lung
1. Shift intake point upstream to Nang Am, build intake works &
pumps to fill Green Blue Lung (capacity of 1,200,000 m3/d)
2. Build the Green-blue Lung (19 km) with total area of 1,000 ha,
of which 200 ha is waterway and 800 ha is a green multi-
functional zone including dikes on both sides of the waterway
(see impression on next page)
3. Build intake works & pumps to Tan Hiep WTP with a capacity of
600,000 m3/d
4. Where land is available additional multi-functional storage /
retention reservoirs can be built, to provide storage for water
supply in the dry season and flood retention in the wet season
5. Develop wetland nature, flood retention and eco-tourism in
the surrounding area of the Green Blue Lung
1
2
4
3
A
B
Green Blue Lung 1000 ha
A. 250 ha
B. 270 ha
*with a production of 600,000 m3/d; water depth at maximum water
level 4 m; at minimum water level 2 m; average width 100 m
**reservoir depth from surface level 15 m; maximum water level 1 m
above surface level; minimum water level 1 m below surface level.
4
6
5
Green Blue
Lung
Res. A Res. B
Retention time at max water level (days) 12* 63** 68
Retention time at min water level (days) 6 55 59
Storage capacity (days) 6 8 9
6. Optional
when salinity
intrusion tipping
point is reached:
controllable
salinity weir and
sluice gate in
Saigon River
28. LONG TERM SOLUTION
#2Multiple-day Reservoir
1. Shift intake point upstream to Nang Am, build intake works
& pumps to fill reservoir A (capacity of 1,200,000 m3/d)
2. Build three storage & pre-treatment reservoirs with total
area of ± 250 ha; connect reservoirs with pipes; water
transport between reservoirs A B C by gravity; pipelines
to bypass each reservoir are foreseen as well
3. Build intake works, pump and pipeline to Hoa Phu with a
capacity of 600,000 m3/d
4. Develop wetland nature, flood retention and eco-tourism
in the surrounding area of ± 250 ha (total area ± 500 ha)
1 2
4
3
A
B
C
A. 84 ha
B. 100 ha
C. 78 ha
Retention time at maximum water level 90 days*
Retention time at minimum water level 70 days
Storage capacity 20 days
* With a production of 600,000 m3/d, reservoir depth of 20 m,
height of embankment 5 m, maximum water level 20 + 3.5 m,
minimum water level 20 - 2 m
6
6. Optional
when salinity
intrusion tipping
point is reached:
controllable
salinity weir and
sluice gate in
Saigon river
29. LONG TERM SOLUTION
#3
Draw Water from
Irrigation Canal K45
1. Create a new intake point at the end of irrigation
canal K45; the design capacity at this point is
1,000,000 m3/d; available capacity depends on
the development of irrigation requirements,
which are projected to decrease further in the
future
2. Build intake works & pumps with a capacity of
600.000 m3/d
3. Build 20 km pipeline to Hoa Phu (2 x 1,500 mm)
4. Existing K45 canal may require rehabilitation
works
5. A storage & pre-treatment reservoir with ± 8 days
of storage may be necessary to cover the annual
maintenance period; an area of ± 85 ha is
required, as well as an additional pumping
station
1
2
3
4
5
30. LONG TERM SOLUTION
#4Pipeline to Dau Tieng
1. Shift intake point to Dau Tieng Reservoir, build raw
water intake and pumping station with a capacity of
900,000 m3/d
2. Build pipeline to Hoa Phu 62 km (2 x 1,800 mm)
3. Build 2 booster pump stations along the route of the
pipeline
4. A pretreatment facility at the intake from Dau Tieng
reservoir may be necessary in order to prevent
sedimentation and biofouling in the pipeline
1
2
3
3
4
31. REFLECTION
ON LONG TERM SOLUTIONS #1-4
1. Green-blue lung
600,000 m3/d
2. Multiple-day
reservoir
600,000 m3/d
3. Draw water from
irrigation canal K45
600,000 m3/d
4. Pipeline to Dau
Tieng reservoir
900,000 m3/d
Mechanism to cope with
salinity intrusion
- Selective intake
(6-23 day storage
capacity)
- Mixing
- (Potentially) salinity
weir in Saigon river
- Selective intake
(21 day storage
capacity)
- Mixing
- (Potentially) salinity
weir in Saigon river
No salinity intrusion No salinity intrusion
Investment estimate (±40%)
(intake, pumps, pipelines)
21 M$ 64 M$ 80 M$ 600 – 1,200 M$
Investment Estimate (±60%)
(earthworks, waterway &
reservoir construction)
790 M$ 475 M$ 120 M$
(if needed to cover
maintenance period on
irrigation canal)
-
Realization period 15 years 10 years 10 years 10 years
Main operational costs - O&M intake, canal,
reservoirs and
pumping stations
- Pump energy
- O&M intake ,
reservoirs and pumping
stations
- Pump energy
- Raw water price per m3
- O&M intake and
pumping station
- (O&M reservoir)
- Pump energy
- O&M intake and
pumping stations
- Pump energy
Multi-functionality Yes: flood retention,
wetland nature,
ecotourism
To limited extent: wetland
nature, ecotourism
- -
32. COMBINING SOLUTIONS
The current planning for Tan Hiep WTPs is to produce 900,000 m3/d by 2025. For the long term solutions #1-3, it is
not clear whether they can provide this, or are limited to 600,000 m3/d. However, it is possible to combine several of
the short and long term solutions to reach a raw water capacity of 900,000 m3/d. Combining solutions enhances the
redundancy and reliability of the overall system (i.e. multiple sources of water).
Option
Long
Term
Name / Capacity Option
Short
Term
Name / Capacity
#1
Green-blue lung
#3
Draw water from N31A irrigation canal
600,000 m3/d 300,000 m3/d
#2
Multiple-day reservoir Nang An
#3
Draw water from N31A irrigation canal
600,000 m3/d 300,000 m3/d
#3
Draw water from K45 irrigation canal
#2
Shift intake upstream to Nang Am + construct
pipeline to Hoa Phu
600,000 m3/d 300,000 m3/d
33. SHORT TERM > > > LONG TERMNOW
Draw water from N31A
irrigation canal
Pipeline to Dau Tieng
Shift intake upstream to
Nang Am + pipeline
Hoa Phu
intake
Improve
flushing
Halt intake at
350 mg/l
Multiple-day reservoir
at Nang Am
Shift intake upstream to
Lang The canal + waterway
Controllable Salinity weir
Saigon River + sluicegate
Connect irrigation canal to
Green Blue Lung
ADAPTIVE PATHWAYS
FOR INFRASTRUCTURE INVESTMENTS
Duong Do Park reservoir
Draw water from K45
irrigation canal
Reservoir to cover
maintenance periods
Lang The canal:
the Green-blue Lung
The adaptive pathways below illustrate whether new infrastructure investments can utilize previous infrastructure
investments. The adaptive pathway can also be used for ‘back-casting’ by selecting the preferred long term solution(s) and
determining which of short term solutions are in line.
