GROUNDWATER MONITORING GROUNDWATER MONITORING REQUIREMENTSREQUIREMENTS

Comment on the differences

between monitoring for

surface and groundwater.

Groundwater’s Status QuoGroundwater’s Status Quo

Millions of m3 pumped every year: Monitored? Who? How?

100’s of thousands of users: Registered? Controlled?

10’s of thousands of wells/boreholes: Registered? Maintained? Info. about location, abstraction levels, water levels, water quality, formation, etc -

1000’s of sources of pollution: Location, nature & quantity of pollutants? aquifer

vulnerability? Many governing departments/institutions:

Joint management ? Coordination / cooperation?

Groundwater is:an extensive, concealed and relatively inaccessible resource.

INVISIBLE..!

General IntroductionGeneral Introduction

One way to make groundwater visible...One way to make groundwater visible... by MONITORING it, e.g: Monitoring groundwater

level shows a declining water table – which allows water managers to obtain an appreciation of the status of the resource.

Year-wise depletion of groundwater

Some Consequences of GW abstraction

Normal consequences of any groundwater

pumping

When pumping is

further increased

Excessivepumping

One way to make grdwater visible...One way to make grdwater visible...(contd.)(contd.)

SYSTEM BASIC FUNCTION WELL LOCATIONS

Primary(Referen

ce)Monitorin

g

evaluation of general 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.

Secondary

(Protection)

Monitoring

protection against potential impacts to:strategic groundwater resourcewell-fields/springheads for public WSurban infrastructure from land subsidencearchaeological sites against rising WTgroundwater-dependent ecosystems

around facilities/areas/

features requiring

Protection.

Tertiary(Pollutioncontainm

ent) Monitorin

g

early warning of groundwater impacts from:• intensive agricultural land use• industrial sites• solid waste landfills• land reclamation areas• quarries and mines

immediately down +

up-gradient from hazard

Groundwater Monitoring Systems by Groundwater Monitoring Systems by FunctionFunction

Types of data for Groundwater Management Types of data for Groundwater Management

DATA TYPE BASELINE DATA (from archives)

TIME-VARIANT DATA (from field stations)

Groundwater Occurrence & Aquifer Properties

hydrogeologic logs, grdwater levels, quality, etc.

well & aquifer pumping tests

grdwater level monitoring

grdwater quality monitoring

Groundwater use

water well pump installations

Water use inventoriesPopulation registers &

forecasts Irrigation energy

consumption

water well abstraction monitoring (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 CycleThe Monitoring Cycle

static & dynamic water levels, water quality

Mgt question &

monitoring objectives, e.g.

trends & changes, impacts & risks, etc.

Mgt of info. & actions

Define actual info. needed, what for, wherefrom..? etc.

needsneeds

ofof

When is groundwater monitoring considered When is groundwater monitoring considered

cost-effective?cost-effective?

it is driven by a specific objective – monitoring for its own sake often leads to inefficient use of manpower and budgets

data collected is: NOT only used for the explicit purpose of

the monitoring programme, but Also systematically stored for future use –

there are far too many cases of monitoring data being lost along the way.

Effectiveness of groundwater monitoringEffectiveness 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

Measuring GW Use Measuring GW Use && Aquifer BehaviourAquifer Behaviour

Primary goal of aquifer management is to:develop groundwater resources on the basis of a policy plan.monitor & control impacts of abstraction on groundwater systems.

Thus, monitoring grdwater abstraction + aquifer water levels provides key information for management of grdwater resources.

Monitoring of:

grdwater abstraction, and

aquifer water levels

combined with management actions –

reduction of pumping – can contribute to

more stable development of groundwater

resources.

Measuring GW Use Measuring GW Use && Aquifer Behaviour Aquifer Behaviour (contd.)(contd.)

Monitoring data

Example: Where historic data reveals over-abstraction.. Establishment of baseline situation: Application of mgt actions, & monitor

QuestionsQuestions

Is there any dedicated monitoring

network in your country, or are

existing production

boreholes used?

Which parameters

are monitored,

and why this choice?

Who is responsible for data collection,

storage, interpretation

and management?

Detecting Groundwater Quality changesDetecting Groundwater Quality changes

Grdwater monitoring requires special sampling procedures as:well pumping + sample handling may cause major sample modification through;

air entry degassing + volatile losses

NEED for appropriate sampling procedures.

Summary of sampling procedures and precautions for Summary of sampling procedures and precautions for specific groups of groundwater quality parametersspecific groups of groundwater quality parameters

In designing a monitoring network,

what key steps would you take in

terms of installation/selection of monitoring wells;

data acquisition (who-by, frequency, etc.); data storage and interpretation

Early warning potential threats to Aquifer Early warning potential threats to Aquifer ++ Groundwater supply quality Groundwater supply quality

a critical requirement for detecting any threats to groundwater quality

Design of monitoring networks necessary, which...

relates to the spatial variation of grdwater flow + quality of more recent recharge....

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

Detection of groundwater quality trends in aquifer replenishment in vicinity of a public-

supply water well

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

ground....

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

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

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

Some objectives of such sampling piezometers:

to facilitate early warning of the onset of groundwater pollution........ – to allow timely introduction of necessary control measures.

to provide advance warning of the arrival of polluted water at an important groundwater supply source and make provision for treatment or other mitigation.

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

Who carries out

the monitoring

?

What important natural or

anthropogenic water quality

problems are in your country?

Network Design

objectives must be defined and program adapted accordingly

groundwater flow system must be understoodsampling locations and monitoring parameters must

be selected by objectives

Systemimplementation

appropriately-constructed observation + abstraction wells must be used

field equipment + laboratory facilities must be appropriate to the objectives

a complete operational protocol + data handling system must be established

groundwater + surface water monitoring should be integrated where applicable

Datainterpretation

data quality must be regularly checked through internal and external controls

decision makers should be provided with interpreted management-relevant datasets

program should be periodically evaluated and reviewed

Basic rules for a successful groundwater monitoring Basic rules for a successful groundwater monitoring programme - summaryprogramme - summary

Network Design

Systemimplementati

on

Datainterpretation

objectives must be defined and program adapted accordingly

groundwater flow system must be understoodsampling locations and monitoring parameters

must be selected according to objectives

appropriately-constructed observation + abstraction wells must be used

field equipment + laboratory facilities must be appropriate to the objectives

a complete operational protocol + data handling system must be established

groundwater + surface water monitoring should be integrated where applicable

data quality must be regularly checked through internal and external controls

decision makers should be provided with interpreted management-relevant datasets

program should be periodically evaluated and reviewed

Thank you for your attentionThank you for your attention