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Best practise of groundwater monitoring in Thailand

Regional Technical Workshop on Groundwater Information in the

Lower Mekong Basin

February 17, 2014

Tussanee Nettasana, PhDDepartment of Groundwater Resources

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Groundwater is:

an extensive, concealed and relatively inaccessible resource.invisible..!

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How to make groundwater visible...

by MONITORING it, e.g: Monitoring groundwater level shows a decreasing water level – which allows water managers to obtain the status of gwresource.

Q1 Q2Q3

Effective groundwater management will

• Protect the quantity of GW and ensure a reliable and

affordable supply of groundwater

• Protect the GW quality to ensure that gw remains

suitable for various uses

• Prevent land subsidence that can damage expensive

public and private infrastructures

System Basic Function Well Locations

ReferenceMonitoring

evaluation of groundwater behaviour, e.g.: trends resulting from land-use change +

climatic variationprocesses such as recharge, flow and

diffuse contamination

in areas withuniform

hydrogeologyand land use.

ProtectionMonitoring

protection against potential impacts to: strategic groundwater resourcewell-fields/springheads for public WSurban infrastructure from land

subsidencegroundwater-dependent ecosystems

around facilities/areas/

features requiringprotection.

Pollutioncontainment

Monitoring

early warning of groundwater impacts from:• intensive agricultural land use• industrial sites• solid waste landfills

immediately down +

up-gradient from hazard

Groundwater Monitoring Systems by Function

Types of data for Groundwater Management

Data Type Baseline DataTime-Variant Data (from

field stations)

Groundwater

Occurrence &Aquifer Properties

hydrogeologic logs, groundwater levels, quality, etc.

well & aquifer pumping tests

groundwater level monitoring

groundwater quality monitoring

Groundwater use

water well pump installations Water use inventories Population registers & forecasts Irrigation energy consumption

water well abstractionmonitoring (direct/indirect)

grdwater level variations

Supporting Information

climatic data land-use inventories geologic maps/sections

riverflow gauging meteorologic

observations

satellite land-use surveys

The Monitoring Cycle

static & dynamic waterlevels, water quality

Monitoring objectives,

e.g. trends & changes, impacts & risks, etc.

Management of info. & actions

Define actual information needed, what for, where from..? etc.

needs

of

Effectiveness of groundwater monitoring

....is improved by careful attention to:

network design

system implementation

data interpretation

data storage from past monitoring activities

accessibility of monitoring stations...

participatory monitoring amongst water users

interpretation and use of data to formulate

management actions

monitoring groundwater abstraction + changes inaquifer water levels can provide key information formanagement of groundwater resources.

combined with management actions – reduction ofpumping – can contribute to more stable developmentof groundwater resources

Measuring GW Use & Aquifer Behaviour

Detecting Groundwater Quality changes

Groundwater monitoring requires special sampling

procedures as:

well pumping + sample handling may cause majorsample modification; it needs appropriate samplingprocedures.

Summary of sampling procedures and precautions for specific groups ofgroundwater quality parameters

Many cities have experienced rapid growth of urban & industrial waste disposal to the ground....

Early warning of potential threats to Aquifer +Groundwater supply quality

And that impactsFrom contamination can be remediated

Water table

From Fetter (1994)

Accidental spill

Municipal landfillSeptic tank

Municipal water well

Ocean

Salinewater

Fresh water

Aquifer (saline water)

Confiningunit

Leaking petroleum tank

Contaminated shallowwell

a critical requirement for detecting any threats to

groundwater quality

.....thus, necessitating a focused groundwater quality management monitoring, using sampling piezometers.

Early warning of potential threats to Aquifer +Groundwater supply quality (contd.)

UC2008 Pre-14

Basic rules for a successful groundwater monitoring programme - summary

Network Design

objectives must be defined and program adapted accordinglygroundwater flow system must be understood sampling locations and monitoring parameters must be selectedaccording to objectivess locations and monitoring parameters mustbe selected by objectives

DataInterpretation

appropriately-constructed observation + abstraction wells must be used field equipment + laboratory facilities must be appropriate to theobjectives

a complete operational protocol + data handling system must beestablished

groundwater + surface water monitoring should be integrated whereapplicable

data quality must be regularly checked through internal and externalcontrols

decision makers should be provided with interpreted management-relevant datasets

program should be periodically evaluated and reviewed

field equipment + laboratory facilities must be appropriate to the

Systemimplementation

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Effective groundwater management will

• Protect the quantity of GW and ensure a reliable and

affordable supply of groundwater

• Protect the GW quality to ensure that gw remains

suitable for domestic, industrial, agricultural, and

environmental uses

• Prevent land subsidence that can damage expensive

public and private infrastructure

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Groundwater Monitoring

• To implement 3 monitoring all at once is expensive

• Due to financial resources are limited, groundwater

level monitoring is the first priority

• Groundwater level monitoring is a direct indicator of

the groundwater supply

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Benefits of Monitoring Groundwater Levels:

• Determine annual and long-term changes of

groundwater in storage

• Determine direction and gradient of groundwater flow

• Understand how aquifer systems work

• Gain insight for well construction and where to set

pump bowls for efficient extraction

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Technical Aspects of s of Monitoring Groundwater Levels:

• Determine the elevation of the ground surface at each monitoring

location

• Types of well to be used in measuring groundwater levels

• Which levels of monitoring wells are perforated or screened and

whether they represent typical extraction wells in the area

• Area to be monitored and number and the locations of

monitoring wells

• Monitoring frequency and time of year

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Important Groundwater Records:

• Name of well

• Location of wellels

• Ground surface elevation

• Date of measurement

• Depth to Groundwater

• Elevation of Groundwater surface

• Document reference point from which to consistency measure

depth of groundwater

• Note of well status (pumping or non pumping) and any

surrounding conditions that might affect groundwater levels

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How do we Measure the Observation?

Head measurements Piezometers, observation wells Pumping wells

Flow Rates Seepage measurements Baseflow recession analysis Pumping tests

Concentration Monitoring wells Pumping wells hydropunch

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Groundwater Monitoring in Thailand

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Groundwater Availability

Groundwater in Porous media

Groundwater in Sedimentary rock

1-30 m3/hr

50-200 m3/hr

30-50 m3/hr

5 m3/hr

20 m3/hr

5-20 m3/hr

1-20 m3/hr

20-50 m3/hr

Groundwater in Igneous/metamorphic rock

GW well distribution

• DGR 340,500 wells• Registered private well 32,500

wells• Provincial Agency 21,527 wells• Dug well and shallow well 439,200

wells

Industry 15 %Agriculture 5 %

Consumption80 %

Groundwater Development in Thailand

Estimated Total Groundwater Utilization is

8,000 M.CU.M./YR

๐ Consumption๐ Agriculture๐ Industry

Department of Groundwater Resources, Royal Thai Government

29%

71%

Government agencies

other agencies &Private sector

No.of Pump Installed Implementing

Agency No of Well

Drilled Hand Pump

Submersible Pump

Engine Pump

Rural Piped Water Supply System

DMR ARD PWD DOH NSC

Other Agency & Private Sectors

90,132 50,102 52,790 39,867 9,475

98,592

37,771 42,257 40,621 27,362 5,914

40,019 2,521 810

- -

28,592

70,000

12,342 5,324 11,359 12,505 3,561

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total 340,958 153,925 141,942 70,000 45,091

Number of Wells Developed by Government Agencies and Private Sectors

Department of Groundwater Resources, Royal Thai Government

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No Groundwater Basin No. station No.well Aquifer

1 Khorat-Ubon 85 124 Porous/fractured

2 Udon-Sakhon Nakhon 2 2 fractured

3 Loei 4 6 Porous/fractured

4 Phetchabun 2 2 Porous/fractured

5 Phrae 3 4 Porous/fractured

6 Nan Porous/fractured

7 Mae Hong Son 2 4 Porous/fractured

8 Lampang 7 10 Porous/fractured

9 Fang 4 7 Porous/fractured

10 Chiang Rai-Phayoa 6 6 Porous

11 Chiang Mai*Lamphun 54 109 Porous

12 Upper Chao Phraya 37 72 Porous

13 Tak 2 4 Porous/fractured

14 Kanchanaburi 2 3 fractured

15 Lower Chao Phraya 220 508 Porous

16 Phetchaburi-Prachuap 4 5 fractured

17 Prachin Buri-Srakaeo 18 26 Porous/fractured

18 Chantaburi-Trat 1 1 Porous/fractured

19 Rayong 85 140 Porous/fractured

20 Chon Buri 64 85 Porous/fractured

21 Surat Thani 9 10 Porous/fractured

22 Nakhon Si Thammarat-Phattalung 33 58 Porous

23 Ranong-Satun 72 131 Porous/fractured

24 Hat Yai 18 50 Porous

25 Pattani

26 Chana

27 Narathiwat

734 1367

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Lithological & Geophysical Logging

Well Design data

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Pumping Test Analysis

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figures of the existing monitoring network

•GW-in Porous media•Karst-GW and GW in fractured rock • Water Quality Sampling as a rule 2x a year

(Analyse Physical and Chemical properties and heavy metal)

• Costs of selection, establishing sampling sites, analyses and data transfer are met by Bureau of Groundwater Conservation and Restoration, DGR

•Costs per year throughout the whole country : 10 to 20 million baht

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Existing groundwater quality monitoring network

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Existing groundwater quality monitoring network

TDS Concentration

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Alluvium Formation Phu Thok Formation Maha Sarakham Formation

Geology

Mahasarakham Formation

Well TP1 Regional Office of Agricultural Extension

391 m

GW Flow

Ban Nong Kranuan Ban Nong Waeng Ban Nong Bua DeemeeBan Tha Phra

Chi River

Ele

va

tio

n (

m.a

ms

l)

Distance (km)

Wat Pa Hin Kaeng

B. Huai Toei

B. Nong KranuanB. Nong waeng

Khon Kaen Brewery

B. Nong Khrai Nun

Ele

va

tio

n (

m.a

ms

l)

Distance (km)

Regional Agri. Office

Groundwater Flow in Confined Aquifers (Phu thokFormation)

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Groundwater Flow in Confined Aquifers (Sand and Gravel aquifer)

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Groundwater Flow in Confined Aquifers

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Spring seepageFlowing well

UC2008 Pre-47

Flowing Artesian well Ban Non Sombun, Amphoe Ban Haet, KhonKaen

Well Depth 120 m Flow 6 m abgsfound fracture at 93-96 m and 105-110 m, free flow rate > 170 m3/hr

Thank you for you attention

Department of Groundwater Resources, Royal Thai Government