This document provides standard procedures for retrieving digital water level data from piezometers using a Digital Water Level Recorder (DWLR). The procedures include: (1) checking equipment and documents before heading to the field, (2) verifying DWLR details on site and taking manual water level readings, (3) synchronizing clocks, checking batteries, and retrieving DWLR data, and (4) documenting all observations and ensuring proper data storage and backup. Following standardized procedures helps maintain accuracy and quality of groundwater level measurements.

1. Government of India & Government of The Netherlands
DHV CONSULTANTS &
DELFT HYDRAULICS with
HALCROW, TAHAL, CES,
ORG & JPS
VOLUME 4
GEO-HYDROLOGY
FIELD MANUAL - PART VII
DIGITAL WATER LEVEL DATA COLLECTION
FROM PIEZOMETERS

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Table of Contents
GENERAL 1
1 INTRODUCTION 2
2 PRE-FIELD CHECKLISTS 2
3 CHECKS PRIOR TO DEPARTURE 4
4 PROCEDURES FOR DATA RETRIEVAL 4
5 DOCUMENTATION OF DATA 7

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GENERAL
The Field Manual on Geo-Hydrology comprises the procedures to be carried out to ensure proper
execution of design of the groundwater water level monitoring network, operation and maintenance of
observation well and piezometers. The operational procedures are tuned to the task descriptions
prepared for each Hydrological Information System (HIS) function. The task description for each HIS-
function is presented in Volume 1 of the Field Manual.
It is essential, that the procedures, described in the Manual, are closely followed to create uniformity
in the field operations, which is the first step to arrive at comparable hydrological data of high quality.
It is stressed that water level network must not be seen in isolation; in the HIS integration of networks
and of activities is a must.
• Volume 4 of the Field Manual deals with the steps to be taken for network design and
optimisation as well as for its operation and maintenance. It covers the following aspects.
• Part I deals with the steps to be taken for network design and optimisation. Furthermore, site
selection procedures are included, tuned to the suitability of a site for specific measurement
procedures.
• Part II details with piezometer construction procedure with details of the different elements and
the significance of different elements in the piezometer construction
• Part III comprises the preparatory activities and procedures for carrying out aquifer tests. The
procedures to be adopted for analysis of pumping test data is briefly discussed
• Part IV comprises the testing and installation of DWLR’s. Procedures to be followed for
procurements and installation are outlined in Volume 4 of the reference manual.
• Part V deals with the need for carrying out Reduced Level Surveys and the procedures in
carrying out the survey are outlined.
• Part VI deals with the standardised procedures to be adopted for manual collection of water level
data from open wells and piezometers.
• Part VII deals with the standardised procedures to be adopted for retrieval of data from DWLR
and integration with the software.
• Part VIII, deals with procedures to be adopted for regular inspection and maintenance of
piezometers and DWLR’s.
The procedures as listed out in this manual are in concurrence with the ISO standards as far as
available for the various techniques and applicable to the conditions in Peninsular India.

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1 INTRODUCTION
In this Part VII an overview of steps in groundwater level measurement using Digital Water Level
Recorder (DWLR) is presented.
Standard Field Procedures have to be adopted for downloading data from a DWLR. The standard
method should be mandatory for implementation by all the groundwater level monitoring teams. The
Data Processing Center in charge through the Field Supervisors shall be responsible for monitoring
the proper implementation of the accepted procedure. The Centre incharge should ensure that the
relevant team members have completed all applicable training’s for carrying out the task and have
obtained the required field equipments in accomplishing the task.
Standard practices need to be implemented to help maintain the accuracy and precision of water-level
measurements. Only Standard Field Procedures that will provide the needed levels of quality
assurance should be consistently employed.
Important field practices, that will ensure the quality of ground-water-level data, include:
• establishment of permanent datum’s (reference points for water-level measurements) for
observation wells/piezometers,
• check to see, whether observation wells/piezometers have any construction defects that affect
the accuracy of water-level measurements,
• ensure that silting, corrosion, or bacterial growth have not affected the piezometer response to
changes in the aquifer,
• carry out periodic inspection of the structure, and
• implement regular hydraulic testing to ensure its communication with the aquifer.
The following personnel should be made responsible for all activities related to water level
measurements, data organisation and interpretation:
• Data Processing Centre - In charge,
• Team Supervisor, and
• All the field personnel involved in the team (field and office).
Systematic procedures should include the pre-field preparatory work, the actual field measurement,
quality checks for ensuring that the monitoring structure are delivering reliable data, data integration
with the dedicated software, data analysis, data interpretation and data communication to the
concerned higher offices.
2 PRE-FIELD CHECKLISTS
Go through the following checklist before heading out for the water level and water quality monitoring.
The checklist needs to be modified to meet agency specific needs and travel plans. The checklist
comprises the following items:
1. Map of the area: Collect the topo sheet/sheets (1:50,000 scale) that contain the location of all
the monitoring sites that need to be visited for water level measurements/ water quality
sampling.
2. Well-Specific Field Sheet: Collect the individual monitoring site details related to site location
map, address, details of the fencing, protection, MP details, height of the MP, reduced level

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elevation at the ground level and MP, lithological details, aquifer position, discharge, aquifer
properties, water level hydrograph updated to the last measurement, details of the maintenance
work if any carried out.
3. Monitoring/ sampling plan: Collect documents and details of procedures (Field Procedures) to
be used for water level monitoring and water quality sampling. Collect the water level recording
format.
4. Equipment Checklist:
• Brunton compass
• Steel tape
• Chalk
• Electric water level indicator
• Steel tape (5 m)
• Water sample bottles
• Marker pen
• Field Note Book
• Palm Top
• Calculator
• Torch
5. Before going to the field:
• Ensure that the measuring equipment is clean, so that it is not a means of introducing dirt or
contaminants into a well/piezometer.
• Preplan the event and make route plan using maps to locate the monitoring wells/piezometers to
be monitored.
• Verify whether access is always available through the shortest route or check for alternative
route.
• Get details of the petrol stations, vehicle repairs, accommodation available along the proposed
route.
• Remember to take the keys to locked boxes and gates as needed. Take oil to grease locks.
6. Spares: The Spares to be taken should comprise the following:
• Spare DWLR
A spare DWLR wherever available should be carried along during data retrieval for replacing non
functional or poorly functional instruments.
• Spare batteries for DWLR (if required) and/or battery charger for DRS.
• High accuracy level tape
It is strongly recommended to use accurate electrical level tape of international standard. To be
used as reference for the DWLR, the tape should have at least four times better accuracy than
the DWLR. If for example the accuracy of the DWLR is 1 cm, then the tape should have an
accuracy of 2.5 mm or better. Note that the cheap electrical tapes, like the ones based on
parallel wire antenna cable, that are available from some manufacturers, do not meet this
requirement. If an accurate electrical tape is not available, then a high quality steel tape should
be selected.
• Multi-meter with capability to measure voltage, current and resistance and measuring wires and
spare batteries. The display should have a resolution of 3 ½ digits or more.

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7. Documents
The following documents should be carried:
• DWLR guidelines manual provided by the supplier,
• Installation forms,
• Instrument history log, (copy of the instrument log file pertaining to the specific DWLR, but also
for the spare DWLR(s) carried for field visit), and
• Station history log.
Note: None of the documents should be original. Only copies should be exposed to field conditions.
The history logs do not have to cover a period of more than one year.
8. Transport box
The transport box used for carrying the DWLR, DRS and other fragile components must be padded
with shock absorbing material to avoiding banging around during transport.
3 CHECKS PRIOR TO DEPARTURE
The following checks should be executed on the primary items and the spares prior to departure:
1. Accuracy of the steel tape: The steel tape is to be checked for accuracy against a known
standard, e.g. a calibrated steel tape which is kept in office for reference purposes.
2. Functioning of the DRS: The separate cursor stick should be available, if applicable. In
particular the DRS models based palmtop PC technology may require a stick type cursor.
3. Setting of the DRS clock: Since DRS time is used to set the DWLR clocks, it is essential that
the DRS clock is accurately synchronised with the national time. Spoken time announcements
are not accurate enough, but the radio/TV beeps, like transmitted by BBC World Service are! If
available, GPS time may be used instead, it is extremely accurate. After setting, the
performance of the clock should be verified.
4. Functioning of the DRS battery charger: The DRS devices consume a lot of energy, in
particular when in communication mode. Therefore a properly functioning battery charger
should be carried. In particular the battery contacts should be clean and in good shape.
4 PROCEDURES FOR DATA RETRIEVAL
The procedure for data retrieval includes:
1. Verify DWLR particulars: Verify from the records the DWLR particulars like serial number,
measuring range and cable length.
2. Check air vent and hydrophobic filter: The air vent should be open. The hydrophobic filter
should be checked for choking by dirt. If needed the filter should be replaced. The air vent and
hydrophobic filter should be kept as high above the ground level as possible to avoid ingress of
water during inundation of the area.

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3. Check desiccator: Check the desiccator and if (partly) saturated, it should be replaced by a
fresh package. In case the desiccator package is damaged, it should also be replaced and all
loose desiccator material carefully removed.
4. Check the cable grip: Check whether the cable grip can be held strongly stable to a rigid point
near the top of the casing. That point should not bend or shift in any way under the weight of the
DWLR with the suspension cable or during the handling of the equipment.
5. Connect the DRS to the DWLR
6. Take from manual observation: Take a manual observation of water level by using the
accurate level tape. The manual observation should be executed several times, preferably by
different observers. Any discrepancies should be verified. It is to be expected that the readings
do not differ by more than 1 cm.
7. Annotate the date and time of the observations: The time of observation is important
because water level may fluctuate e.g. due to nearby pumping or tidal effect.
8. DWLR and DRS clock synchronisation: Synchronise the DWLR with the DRS clock: make
log sheet entries of DWLR and DRS time. Errors in the setting of the DWLR’s system clock
result in erroneous time labels in collected data. The higher the water level rate of change the
more important the clock’s setting and associated time keeping is.
9. Check the DWLR clock against the DRS clock: Make log sheet entries of DWLR and DRS
time.
10. Battery check: Do a DWLR battery voltage reading, make an entry in the log sheet, and
assess the remaining capacity. Nearly exhausted batteries have to be replaced by new ones.
Remaining battery capacity must be more than adequate to keep the DWLR fully operational up
to next service visit, this including a practical safety margin.
For most the battery types, the remaining capacity can be estimated from the battery voltage.
However, some of the Lithium batteries have such a flat discharge curve that the voltage is not
a proper indicator. With such batteries, the voltage does only drop when the battery is about to
become depleted.
Battery capacity may be tested by applying a specific load (resistor) to the battery and
measuring the load current and / or the voltage. The best method should be obtained from the
vendor (instrument or battery).
Care should be taken that used DWLR batteries are not mixed with new ones. Write the date of
installation on batteries using a waterproof fibre tip pen
11. Obtain an instantaneous water level reading from the DWLR: This should be done
immediately after the manual observation was obtained. The instantaneous reading should be
really instantaneous and not of some time ago.
12. Compare manual observations with the DWLR reading.
13. Retrieve the collected data from the DWLR

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14. Check the retrieved data for consistency: The station particulars should be correct. Verify
the data and time labels of the recorded water level data. The water level values, expressed in
metres relative to top-of-casing, should be the same as the manual observations; i.e. the
difference should stay well within the instrument accuracy limits. The water temperature, if
recorded, should have a reasonable value.
15. Storage and back-up of DWLR data: Do not erase any DWLR data, first the retrieved data
have to be stored and reliably backed up in the office. It is recommended to keep all the data on
the DWLR. This is most easy if the logger memory is organised in a ring structure. The ring
structure implies that when the memory becomes completely filled, the oldest data gets
overwritten by the new data.
Under normal conditions, the retrieve function should automatically retrieve the new data only.
The already retrieved data does not have to be retrieved again, unless data were lost or
corrupted during transport/transfer to GEMS in the office. In that case, there should be an
option to retrieve data starting at an user-defined date: that is the date of the latest correctly
transferred data, or retrieve all the recorded data.
16. Consistency check: Verify the internal consistency of the time series, e.g. by displaying a time
series graph. This graph should display sufficient detail to make these verifications. It is
therefore required that the level and time scales are adjustable and zooming-in on particular
data events is supported by the software (see Figure 4.1).
Figure 4.1:
Typical display of time series
graph
17. Shut communication down and disconnect: Check that the DWLR is left in the proper
recording mode before disconnecting and make a note of this.
18. Place the protection cap on the DWLR communication connector
19. Check proper fixing of DWLR suspension and safety wire
20. Cable handling: Carefully coil the free end of the electrical / suspension cable taking care not
to introduce kinks. The air-inlet and communication connector should be kept as high as
possible above the ground. In particular when there is a risk of flooding.
21. Close the well head and attach locks as applicable
22. Close and lock the well housing

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5 DOCUMENTATION OF DATA
All actions and observations should be noted in the related log sheet. Time dependant observations
should be given a time tag. Water level readings by level tape and DWLR should be taken quickly
after each other to avoid difference due to change of water level between both observations.
Off-loaded data are to be copied immediately to an independent medium, which is kept in the station
office. The primary data are transported to the custodian office and loaded into GEMS and subsequently
backed-up.
If any flaws in the data or the functioning of the DWLR are detected then these have to be
documented and reported immediately. Prior to departing, the DWLR operator may have to execute
some trouble shooting tests and trials on site. Refer to the DWLR manual for details. The instrument
should not be opened at that occasion.
Immediately on returning to the office, the flaw has to be reported and immediate actions have to be
organised to remedy the DWLR problem.