Establishing a surface water quality monitoring network for the Mekong delta,Viet Nam

Establishing a surface water quality monitoring network for the Mekong delta,Viet Nam... PROPOSAL ON ESTABLISHING A SURFACE-WATER QUALITY MONITORING NETWORK FOR THE MEKONG DELTA, VIETNA

Establishing a surface water quality monitoring network

for the Mekong delta,Viet Nam

PROPOSAL ON

ESTABLISHING A SURFACE-WATER QUALITY MONITORING NETWORK

FOR THE MEKONG DELTA, VIETNAM

prepared by

College of Technology, CanTho University, Vietnam

(Version 22 July 2004) - oOo -

I INTRODUCTION AND RATIONALE

1.1 The Mekong Delta and its main environmental problem

Mekong River, the 11th largest river in the world, is the main water source for irrigation, fishery, and domestic use… In short, the living of the whole population in the Mekong Delta (MD) is depending and will be depended on this resource

The MD of Vietnam is located at the most downstream part of the Mekong river basin With a population of 17 million inhabitants living in 4 million hectares of land, the MD has great potentials for agricultural production The MD is the most important agricultural production region for the whole country It supplies for more than 50% of staple food and 60% of fish production and accounts for 27% of the total GDP of Vietnam Rice and fishery products contribute significantly to the nation’s export earning

The MD is a typical river delta, with a dense water system of natural creeks, small rivers Besides, artificial canals for irrigation, drainage and navigation have been constructed throughout the whole region Farmers, accounted for 85% of the total population, are living in communities, which are split into small parcels, along the waterways Only 30% of them can access to safe water, the rest using directly surface water at the rivers or canals Unfortunately, as the consequences of a fast-growing economy, which is strongly based on agriculture, the region

is facing more and more severe environmental problems like pollution of water resources by pesticides, fertilizers and animals manure, etc., especially since the past ten years While most of local farmers have to depend totally on the surface water for drinking, irrigating their crops, fishing, aquaculture, etc., protection of this water source is crucial to ensure sustainable development of the MD Recognizing this urgent issue, recently the Vietnamese government has promulgated two important decrees in order to protect the water resource These are:

The decree No 200 of the Prime Minister dated April 4th, 1994

The decree No 36 CT/TW dated June 25th, 1998

However, the surface water quality in the MD is still changing in the complicated way due to following:

1.2 Problems related with water

Located at the downstream end of the River, the MD will face all possible impacts from upstream activities, which cause changes in quantity and/or quality of water (Ta Quang Ngoc 2000)

Surface-water quality problems are classified according to natural conditions due to topography and geology of the delta The development of the delta at the moment and in the near future, beside positive impact, will also lead to environmental pollution Development of agricultural sector and urbanization are main issues affect the water quality Use of excess and improper of fertilizer leads to enrich water body by nutrients together with poor drainage in impression areas

in the MD, will impair water quality Trophic state of water body at present is in hypertrophic level; in addition the use of pesticide, fungicide, insecticides is not controlled Most of micro-organic pollutants are DDT, DDE, Dieldrin…

Rapid urbanization in some rural areas, combined with backward behaviors as making on the canal overhung latrines, directly discharge of domestic wastes to canal system without any treatment and others cause oxygen deficiency in water body

1.2.1 Problems on water quantity

1 Shortage of fresh water for irrigation in the dry season

In 1999, a total area of 1.4 millions ha of spring-rice crop (dry season crop) needs irrigation Water demands are increased proportional with rice cultivation areas From 1995 to 1999, newly reclaimed areas available for rice cultivation has increased by 105.000 ha/year (Statistical Yearbook 2000)

The main thrust of water resources development may be on-farm development and canal improvement (enlargement of existing, and construction of new primary and secondary canals)

to bring more irrigation water to the already irrigated areas and to improve drainage conditions and promote flushing of acid water Embankment improvement in the deeply flooded areas could prevent flooding till the end of August In the shallow flooded, already more developed areas; full year round protection is possible

Both rainfall and river flow have a pronounced seasonal patterns Periods of water excess alternate with periods of water shortage, and water control measures must essentially adapt to this regime feature Virtually the only source of water for irrigation is the Mekong River, which can with relatively minor improvements of the existing canal system, be channeled to all part of the MD except for the southern and western part of the Ca Mau Peninsula The discharges of the Mekong river system are adequate to meet the irrigation water requirement during the early part

of the dry season and in June, a month with frequent dry spells after the start of the wet season However, during the March – May period, Mekong discharges are low and are required to prevent deep saline water intrusion Higher rates of abstraction would increase salinity intrusion which is already affecting large areas

2 Flood

An area of 1.2 to 1.9 millions ha of the MD is under annual floods The severity degree and frequency of the floods is increased Within the past forty years, four substantial floods have occurred in the following years: 1961, 1978, 1991 and 2000

During the period of high river discharges, the banks of the Mekong river system are overtopped

on a large scale and the land is inundated This inundation usually starts in July /August ands in November/December As there is considerable attenuation of the river water levels and progressively increased capacity of the river system downstream, the river flood inundation decrease downstream In the south, excess rainwater also leads to large-scale inundation of the land outside the river-flooding zone This occurs especially in the southwestern part of the MD,

typically in June/July Large areas remain waterlogged and inundated for most of the rainy season

In view of the limitations on land use imposed by excess water due to flooding and rain, the dry season is the main crop production season The discharges of the Mekong river system are quite adequate to meet the irrigation water requirements of the Delta during the early part of the dry season However, during the February ÷ May period Mekong discharges are low Appreciable net outflow from the Delta is required to prevent deep saline water intrusion The river and canal water in many parts of the coastal area is too saline to be used for irrigation purposes The affected zone is rather small at the beginning of the irrigation season, but irrigation intake points become affected as the salinity intrudes further inland in parallel with decreases in net outflow from the MD

Acidification of canal water is a problem in areas with large concentrations of acid sulfate soils; especially during May ÷ July when the acids from the soil enter the canals with drainage of the early rains Acidification of canal water can in general be managed by providing adequate through-flow in the effected area, but as reclamation of acid sulfate soils progresses this may not longer hold true

The subsoil of the MD contains huge quantities of groundwater Its exploitation, however, is constrained by 3 factors: (1) the quantity of the water in the five aquifer, mainly salinity, (2) the permeability of the aquifers, and (3) the fresh water recharge of the aquifers, which determine the safe yield However, when considering the expected urbanization in the MD, this quantity is actually small It should therefore be reserved for urban and rural water supply use only, predominantly for rural areas and town that cannot avail of good quality surface water

1.2.2 Problems on water quality

In large parts of the MD, clayey sediments deposited under brackish or saline conditions contain soluble sulfates In these, sulfate-reducing bacteria convert the sulfate to sulfides under anaerobic conditions This result in the formation of hydrogen sulfide – a highly toxic gas – and iron sulfide, pyrites, FeS2, an insoluble non-toxic compound

Acid sulfate soils, form when soils containing iron sulfide are exposed to oxygen, cover 1.6 millions ha (40%) of the MD (Minh et al 1996) Soils with high iron sulfide content do not usually become a problem so long as the soil remains inundated (Brinkman, Ve, et al 1993) Agricultural activities in the acid sulfate soils, especially in the large scale in the 2 severely acid regions, Plain of Reeds and Long Xuyen Quadrangular (with a total surface area of more than 1 million ha), major cause of water pollution in the region

The most significant detrimental properties of acid sulfate soils are:

• Release of acid (and sometimes toxic) drainage water which causes detrimental impacts

on the environment downstream

• Fixation of phosphorus in the form of insoluble aluminum or iron phosphate This locks

up phosphate from surface and groundwater, leading to phosphorus deficiency and a fall in primary productivity

rice), where located most of the poor provinces with a high ratio of poor farmers Shortage of drinking water is another diversity for local people In order to prevent further salinity intrusion,

it is necessary to keep flows from dropping too low (WB-ADB 1996)

The reduced freshwater flows allow salt water to penetrate further upstream into the estuarine channels, changing the chemical environment and causing substantial changes in the species composition of the local ecological communities A major effect has been to reduce the growth

of the littoral brackish forests which help to bind the soft silt soils, and this permits enhanced erosion rates of the seaward coastline in many areas of the MD

The delta experiences severe salt intrusion through channels and creeks, reaching a peak in April/May, corresponding to the end of the dry season and the lowest flows in the Mekong river system In some areas, salinity has led to the contamination of the sweet water in near surface aquifers, to the point at which it is unfit for consumption

3 Pathogenic pollution and public health problems

Domestic wastewater contains pathogenic bacteria, viruses and parasitic organisms which originate from human and animal waste Conventional physical and biological sewage treatment processes, when available reduce the number of these organisms, but the large number remaining represent a severe public health hazard

Especially at risk are people who use the water for cooking, washing and bathing in contaminated waters Also at serious risk are those who consume fish, shellfish and other aquatic animals and plants that have accumulated pathogens from the water in which they live Shellfish grown in polluted waters are particularly liable to infect consumers, since they filter large volume of water in feeding and may be consumed raw or after insufficient cooking

During the dry season, there is in many areas in the delta a serious lack of drinking water The water quality of the surface-water of the delta has a tendency to get worse when going downstream Because of rapid urbanization in the Delta that leads to high population densities The low basic sanitary condition, in form of overhung latrines above public channels and fishponds it is expected that the surface-water contain high concentrations of fecal coliform bacteria Most of wastewater is diverted directly into the rivers and the canals In addition, people living along the rivers and the canals or in boats dispose solids and liquid waste into the water Besides, feeding fish by night soil in the fishponds connected to the rivers or canals is a popular economic source which makes the surface-water contaminated As many people in the area drinks straight from the surface water, enteric infections and diarrhea diseases are widely spread in the area

If appropriate measures are not taken to reduce the discharges of domestic waste products into the ambient environment, then probably the capacity of the nature to decompose and turnover these waste products will be exceeded in the near future This assumption is based on the dramatically increase in the growth of population in the past 20 years The development of the

MD in the near future is expected in high rate in which urbanization will cause serious degradation of water quality

Besides causing aesthetic water pollution problems, dumping or discharge of organic matter into receiving water bodies also creates oxygen deficiency After being discharged into the water the

organic matter starts decomposing This process is oxygen consuming and temperature dependent and the high temperature in the Mekong River system all the year around will accelerate this process If the receiving water bodies do not have the oxygen renewal capacity which is required to accommodate the amount of discharge organic matter, oxygen depletion can result in killing of fish and other aquatic organisms which depend on oxygen from the water itself The variation of dissolved oxygen is quite various at different sites in the MD

Oxygen saturation levels in the relatively high temperature water of the Mekong River system are comparatively low, and an average BOD of 3 mg/L corresponds to actual concentrations of dissolved oxygen of only around 5 mg/L Many river fish become respiratory dependent at or near this level This means that the hemoglobin in their blood is unable to carry its full potential loading oxygen, and this may alter their ability to survive or compete with others less affected

So apparently harmless low levels of organic pollution may still have substantial environmental impacts at the species level If adversely affected species are significant in human diets, then there may be negative impacts on human nutrition and health

Nutrients such as nitrogen and phosphorus are essential for the growth of all plants Discharge of nutrients into the rivers might be beneficial to the growth of algae and seaweeds and thus to other aquatic biota as well as for irrigation purposes High concentrations of nutrient from domestic sewage and industrial effluent or excess fertilizer runoff from cropped areas into rivers might result in dense algal growth and eutrophication problems

In eutrophic (nutrient enriched) conditions, the ability of the heavy blooms of phytoplankton to detoxify organic and some inorganic contaminants may be very high

Whilst this may appear reduce the environmental risks from toxic pollutants, the subsequent incorporation into the food chain after the algae have been grazed by zooplankton and larger herbivores, with its attendant probability of unpredictable biological accumulation at higher trophic levels, raises other risks to the stability of the dynamics of the ecological communities These may include selective mortality of species and unquantifiable – but nevertheless, very real – public health hazards

Every year, floodwater inundates a great part of the delta area and carries biocide residues into the river system for dispersal into the sea at the coast However, the picture is complicated by the common practice of adulterating these expensive chemicals with large quantities of cheaper and, fortunately, usually much less toxic adulterants

In all estuaries, the relatively short zone in which the fresh/saline water interface ebbs and follows with each tide represents an efficient “nutrient trap”, in which many minor chemical contaminants become concentrated Because of the uncertainty of the actual active ingredient concentration of these materials, and the poor records of their use, no reliable data on the potential risks to the general inland environments can be calculated There is an urgent need for monitoring their presence in the estuarine nutrient trap zones, since their effects on communities

in this zone may be far more significant than in many other habitats

6 Hazardous substances pollution

Dumping of solid waste products in landfills will always create a potential risk of leaching of environmentally hazardous substances and contamination of groundwater and surface waters Discharge of industrial wastewater which contains toxic substances and accidental spill of chemicals during transportation may result in serious environmental pollution Toxic substances

that will accumulate in the environment, such as certain metals, pesticides and other organic substances resistant to bio-degradation, require particularly cautious regulation since their effect may be irreversible or present hazards to consumers of the water, i.e for drinking or aquatic organisms

At present the MD is not detrimentally impacted due to discharges of industrial waste products However, in near future with rapid development in the region, this should be taken into consideration, the responsible environmental authorities has to establish an industrial management plan aiming at protection the environment against industrial discharges

Annually, Department of Science Technology and Environment (DOSTE) of 11 provinces in the

MD organized two campaigns for monitoring surface-water quality Those activities are useful when they want to observe about surface-water quality in their basin In addition, those results could be used to orient the development of their provinces However, the results of this campaign could not be used in the effective way because of the following reasons:

• The sampling and analyzing techniques are varied from province to province

• There is not a common format for managing the data

As the consequent, up to now, the whole picture of the water pollution evolution of the MD cannot be drawn Recognizing the urgent need of the establishment of a Water quality monitoring network for the MD that use the unified technique and data base for sharing the information, Cantho University (CTU), the center of education and research in the MD (see annex) is writing this project proposal calling for support

II OBJECTIVES OF THE PROJECT

2.1 Overall objective

Establishing the Mekong Delta Water Quality Monitoring Network in which CTU will be the center of this network The members of this network are CTU and DOSTEs in the MD, other institutions in the countries along the Mekong River These members will use the same analysis, sampling methods and equipment They will build a unified database for recording and sharing data The data will be used for prediction the change of surface-water quality in the MD

4 Upgrading the capacity of lab technicians

5 Establishing unify database for recording and sharing collected data

6 Establishing a model for predicting the trend of water quality in the MD

III ACTIVITIES

3.1 Partner coordinator missions to Vietnam

Term of Reference:

• Identification of project feasibility

• Discussion on project management aspects

• Need assessment: expert missions, training subjects, resources, etc

3.2 Initiative workshop in Vietnam

Target group:

• Leaders, representatives of DOSTEs and Environmental Monitoring Station

• Staff of CTU who are teaching, doing the research on environmental issues

• Analyzing methods, especially the ones that are suitable with used equipments

• Applied GIS to Water Management

3.4 Training in foreign country

2 MSc in:

• Applied Informatics in Water Quality Monitoring

• Water Quality Management

3.6 Library and Information Unit

A bookshelf specializing on Water Resources Management to provide information to staff for their monitoring activities will be established The information unit with a server for update and share the monitoring result will be establishes at managed at CTU

3.7 Monitoring

Twice a year the DOSTEs will organize the monitoring campaigns The analyzing result will be recorded in the same format and send to information unit The data will be processed by the experts of information unit then shared to the members of the network

IV EXPECTED OUTPUTS

1 A water quality-monitoring network for the MD

2 Qualified staff members (2 MSc., and 24 lab technicians) specializing on water quality management, water quality monitoring, water quality analysis, computer network development and maintenance

3 Well and synchronous-equipped Water Quality analysis Lab

4 Information unit that can process and share the data to the members of the network

5 Water quality computer models modified and adjusted to the conditions in the MD

V DESCRIPTION OF PARTNER INVOLVED IN THE PROJECT

• Member: Mr Nguyen Hieu Trung, Vice Director, Environmental Engineering and Renewable Energy Center, Cantho University (MSc in GIS, International Technology Center, The Netherlands)

• Member: Mr Le Anh Tuan, senior lecturer, College of Technology, CTU (MSc in Water Resources Engineering, AIT, Thailand)

• Member: Mr Nguyen Vo Chau Ngan, lecturer, College of Technology, CTU (MSc in Sanitary Engineering, Catholic University of Leuven, Belgium)

• Members: representatives of DOSTE of eleven provinces in the MD

VI TIME SCHEDULE

The project will be implemented in 5 years from 2003 - 2008

VII ESTIMATED BUDGET

The project will be carried out based on share-burden budget

The DOSTE will contribute the cost for analyzing water samples that are calculated as the followings:

Contributing budget of DOSTEs

Province Cost (US dollar/year) Total contribution in 5 years (US dollar)

CTU will contribute:

• Room for information unit

• Qualified staffs

• Places to organize seminars, training courses

• Man-power to develop and maintain computer network

Foreign partner will contribute:

• Cost for organizing seminars, training courses, project evaluation workshop

• Cost for equipments

• Experts’ cost

These costs could be calculated as the followings:

Investment

costs (USD)

Amount Total costs

(US dollar)

Training in foreign country

- MSc on in Water Quality Monitoring 35.000 01 35.000

- MSc on in Water Quality Management 35.000 01 35.000

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University

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Choowaaew Sansanee (ed.) 1992 Proceedings of the Workshop on Wetlands Management

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Publisher Ha Noi

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University Publishing House Ho Chi Minh city [in Vietnamese]

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surface water as affected by land use in acid sulphate soils in the Mekong river delta, Vietnam J Water Management and Ecosystems 61: 19-27