This document describes the process of mapping ground water quality in India. Ground water quality maps are created under the Rajiv Gandhi National Drinking Water Mission to identify potable ground water sources. The process involves organizing legacy ground water quality data, creating layers of ground water quality points and parameters, integrating the layers to produce maps corresponding to scales like 1:50,000. Quality checks are performed during and after the mapping process. The maps serve as a database for rural drinking water supply projects.

1. Ground Water Quality
Mapping

2. Background of GWQ mapping
Under Rajiv Gandhi National Drinking Water Mission
(RGNDWM)-Operational project sponsored by Ministry of
Drinking Water & Sanitation, Govt. of India
Maps are expected to serve as a database for identifying
potable GW sources & locations for site-specific RS for
supplying drinking water to rural habitations
National Remote Sensing Centre / ISRO in collaboration
with various Central & State Govt. Departments
as Partner Institutes
Executed
by
Mode of
execution
Scope of
the data
Creation of spatial data base on ground water quality
in the form of ground water quality maps for entire country
Objective

3. Pre - monsoon
Post - monsoon
Origin of contamination - Geogenic
and anthropogenic origin
Source of contamination - Point and
Nonpoint sources
Governing factors
of contamination – Chemical &Physical
properties of Geological material
Concentration of
contaminants - changes
with recharge
Contaminants
concentration – high at min
WL & low at max WL
GWQ in terms of space GWQ in terms of time
Unit of factors governing
contamination - Aquifer
Background Concept
Aquifers
(Shallow and deep aquifers)
Ground water zones
(Dynamic and Static zones)
Depth - wise analysis Season - wise analysis
Unit of factors governing
change in concentration -
Aquifer

4. Ground water quality mapping methodology flow chart
Organized Legacy data
excel tableAnalysis,
Interpretation &
Organization
Interpolation
using statistical
method
Parameter-wise ground
water quality layers
Ground water quality
point data layer
Legacy GWQ data
Fresh GWQ data
Lat-Long data
Satellite Data
Habitation data
Integrated ground
water quality layers
Intermediate
outputs
Ground water
quality point
data layer
Intermediate
outputs
Parameter-wise
ground water
quality layers
Grouping &
Union of layers
Ground water quality
map (corresponding to
1:50,000 scale toposheet)
Intermediate
outputs
Integrated GWQ
layers, Base map
layers
Final
output
Validation, Map
composition &
Clipping
Input data Process Output data

5. Outputs generated
Organized input Legacy ground water quality data
Excel format
E00 file & shape file format
Ground water quality data point layer
Parameter-wise
Ground water quality layers
(Depth & Season-wise)
Integrated Ground water quality layers
(Depth-wise)
Ground water quality
map of entire study area
Ground water quality
map corresponding to
1:50,000 scale toposheet
Mxd file format
Tabular Data-
Intermediate
output
Layers-
Intermediate
output
Maps-
Final output

6. Legacy ground water quality data

7. Legacy ground water quality data – Formatting
Data collection – ensured collection of all the available data
Excel table structure – Followed classification system & standards
Redundant data points elimination – Apply criteria for identifying duplicate points
Location Description Depth of well
Date of sample
collection Ground water quality data
Drinkingwatersources

8. Legacy ground water quality data –
Elimination of redundant data points
Example of Allagi-B habitation
Elimination of redundant data points –
Based on identification of duplicate points

9. Ground water quality data point layer
Dummy point features – Criteria followed;
RGNDWM habitations’ geospatial position as a reference
Point
data
Datum & Projection of layer –
WGS 84 Datum & LCC / TM Projection
as applicable to given state

10. Field name Field type Key(Y/N) Remarks
GWQWL-Code 2,2,C Y Feature code
D-Name 25, 35 , C N District Name
B-Name 25, 35 , C N Block Name
P-Name 25, 35 , C N Panchayat Name
V-Name 25, 35 , C N Village Name
H-Name 25, 35 , C N Habitation Name
L-Name 25, 35 , C N Location Name within habaitation
GWQWL-Depth 25, 35 , C N Depth of well / Type of the well
GWS-Date 10, 10 , C N Date of ground water sample collection
CaCo3 4,4,C N Concentration of CaCo3 in water sample
Fe 4,4,C N Concentration of Fe in water sample
SYM-CODE 2,2,I N Symbol code for representing the wells
Ground water quality data point layer
GWQWL-Code GWQWL-Depth
01 Open dug / ring well
02 Dug-cum-bore / tube well
03 Bore / tube well with power pump
04 Bore / tube well with hand pump
Numeric codes to be used for representing type of well
Data base structure
Attribute
data

11. Depth-wise segregation
of legacy ground water quality data points
Criteria for Depth-wise segregation –
i) Vertical variations in hydrogeomorphic units
ii) Ground water zones
Hydrogeomorphic unit-3 Hydrogeomorphic
unit-1
Hydrogeomorphic unit-2
Ground water zone 2
Ground water zone 1Ground water zone 1 Ground water zone 1 Shallow depth zone
Deeper depth zone

12. Depth-wise segregation
Season-wise segregation
of legacy ground water quality data points
Criteria for season-wise segregation –
Date of ground water sample collection
Criteria for identification of periods of seasons in the given region / state –
Minimum & Maximum water level data;
minimum stands for pre monsoon & maximum stands for post monsoon season

13. Density of ground water quality data points –
Representative 20 to 25 points in an area of 700 sq km
(1:50, 000 scale toposheet area)
Geospatial position of ground water quality data points –
Latitude Longitude data collected using good accuracy (+/- 10m) GPS
Distribution of ground water quality data points –
Uniform through out the mapping unit
Authenticity of ground water quality data points –
Validation with FTK ground water quality data
Mapping unit-wise
ground water quality data point layer
Point
data
Area where there are no ground water quality data points –
Carve out as separate polygons not to take in to account
Datum & Projection of layer –
WGS 84 Datum & LCC / TM Projection
as applicable to given state

14. Mapping unit-wise
Ground water quality point data layer

15. Quality parameter-wise Ground water quality layer
(of APO-12 aquifer)
(with automatic classes)

16. Sl. No
Element
Potable
Non-
Potable
Desirable limit Permissibl
e limit
1 pH 6.5 to 8.5 -- <6.5 to >8.5
2 Total Hardness (as CaCo3) mg/l 0-300 300-600 > 600
3 Iron (as Fe) mg/l 0.0 0.3 0.3-1.0 > 1.0
4 Chlorides (as Cl) mg/l 0-250 250-1000 > 1000
5 Total Dissolved solids mg/l 0-500 500-2000 > 2000
6 Bicarbonate (as MG) mg/l 0-500 -- > 500
7 Calcium (as Ca) mg/l 0-75 75-200 > 200
8 Magnesium (as Mg) mg/l 0-30 30-100 > 100
9 Nitrate (as NO3) mg/l 0-45 45-100 > 100
10 Sulphate (as SO4) mg/l 0-200 200-400 > 400
11 Fluoride (as F) mg/l 0.0 1.0 1.0-1.5 > 1.5
12 Manganese (as Mn) mg/l 0.00-0.10 0.10-0.3 > 0.3
13 Sodium (as Na) mg/l -- -- --
14 Potassium (as K) mg/l -- -- --
15 Arsenic (as As) mg/l 0.00-0.05 -- > 0.05
16 Phenolic Compounds (as C 6H5OH)
mg/l
0.000-0.001 0.001-0.002 > 0.002
17 Mercury (as Hg) mg/l 0.000-0.001 -- > 0.001
18 Cadmium (as Cd) mg/l 0.00-0.01 -- > 0.01
19 Selenium (as Se) mg/l 0.00-0.01 -- > 0.01
20 Copper (as Cu) mg/l 0.00-0.05 0.05-1.5 > 1.5
21 Cyanide (as CN) mg/l 0.00-0.05 -- > 0.05
22 Lead (as Pb) mg/l 0.00-0.05 -- > 0.05
23 Zinc (as Zn) mg/l 0-5 5-15 > 15
24 Anionic detergents (as MBAS) mg/l 0.0-0.2 0.2-1.0 > 1.0
25 Chromium (as Cr6+) mg/l 0.00-0.05 -- > 0.05
26 Polynuclear aromatic hydro
carbons (as PAH) mg/l
0.0-0.2 --
> 0.2
27 Mineral Oil mg/l 0.00-0.01 0.01-0.03 > 0.03
28 Pesticides mg/l 0 0-0.001 > 0.001
29 Radioactive Materials α emitters pci/l 0 0-0.1 > 0.1
30 Radioactive Materials β emitters pci/l 0 0-1.0 > 1.0
31 Alkalinity mg/l 0-200 200-600 > 600
32 Aluminium (as Al) mg/l 0.00-0.03 0.03-0.2 > 0.2
33 Boron mg/l 0-1 1-5 > 5
Criteria used
for classification
of ground water
quality -
Bureau of
Indian Standards
(BIS)

17. Quality parameter-wise Ground water quality layer
(of APO-12 aquifer)
(with classes as per BIS Standards)

18. Element-wise
ground water quality layer
Alphabetical code
to be used for the layer
Ground water quality layer of CaCo3 in
shallow aquifer of pre-monsoon
GWQ Layer-CaCo3-Sh-Pr
Ground water quality layer of CaCo3 in
shallow aquifer of post-monsoon
GWQ Layer-CaCo3-Sh-Po
Ground water quality layer of CaCo3 in
deep aquifer of pre-monsoon
GWQ Layer-CaCo3-Dp-Pr
Ground water quality layer of CaCo3 in
deep aquifer of post-monsoon
GWQ Layer-CaCo3-Dp-Po
Ground water quality layer of Fe in
shallow aquifer of pre-monsoon
GWQ Layer-Fe-Sh-Pr
Ground water quality layer of Fe in
shallow aquifer of post-monsoon
GWQ Layer-Fe-Sh-Po
Ground water quality layer of Fe in
deep aquifer of pre-monsoon
GWQ Layer-Fe-Dp-Pr
Ground water quality layer of Fe in
deep aquifer of post-monsoon
GWQ Layer-Fe-Dp-Po
Naming conventions to be followed - Alphabetic codes

19. Field Name Field Type Key (Y/N) Remarks
GWQ-Value 11, 11, C Y Numerical value (as range) indicating
concentration of the element in ground water
GWQ-Code 2, 2, C N Numerical Code indicating ground water quality
class i.e Potable, Permissible, Non-Potable
SYM-Code 2, 2, I N Symbol code for representing ground water
quality class in the map
Quality Parameter-wise
ground water quality layers
Numerical Codes to be used for representing different
ground water classes
Sl. No. Water quality class Numerical code
1. Potable water with desirable limits 01
2. Potable water with permissible limits 02
3. Non-potable water 03
Symbol Codes to be used for representing different ground water classes
Polygon features Symbol Code Symbol
Potable water with desirable limits 1
Potable water with permissible limits 2
Non-potable water 3
Data base structure
Attribute
data

20. Integrated ground water quality layer layers
Polygon
data
Datum & Projection of layer –
WGS 84 Datum & LCC / TM Projection
as applicable to given state
Criteria followed for classification of ground water quality –
Derivative combined quality
Number & kind of integrated ground water quality layers derived –
Separate layers for separate depth zones;
Shallow & deeper depth zones
Criteria followed for dissolving duplicate units –
i) Units in which no GWQ data points,
ii) Contiguous units having same quality,
iii) Narrow units occurring in the periphery of large polygons,
iv) Very small units occurring in isolation within the large units
Accuracy of ground water quality units –
Validation using data points of ground water quality data point layer

21. Field name Field type Key (Y/N) Remarks
GWQ-Code 2,2, C Y Numerical code indicating ground water quality
class is to be given. (refer table-11)
PGWQ-Value 100, 100,C N Alpha-numeric code indicating element-wise
ground water quality, as value, is to be given.
eg. Fe-1.0 mg/l, TDS-1500 mg/l, ….. As-0.01 mg/l
‘Pr’ or ‘Ps’ may be added as pre-fix to indicate the
season respectively.
PGWQ-Code 100, 100,C N Alpha-numeric code indicating element-wise
ground water quality, as class, is to be given.
eg Fe-1, TDS-2, …….As-1‘Pr’/‘Ps’ may be added
as pre-fix to indicate the season respectively.
SYM-Code 2,2, I N Symbol code (colour scheme) for representing
ground water quality in the map is to be given.
Integrated ground water quality layer
Numerical Codes to be used for representing different ground water classes
Sl. No. Water quality class Numerical code
1. Potable water with desirable limits 01
2. Potable water with permissible limits 02
3. Non-potable water 03
Data base structure
Attribute
data

22. Ground water quality map
(Regional / State / Corresponding to 1:50,000 scale SOI toposheet)
Map part
Ground water
quality units
Base map details
Aquifer units

23. Column 1- Map Unit
Column 2- Aquifer unit description
Column 3- Pre monsoon Ground water quality
Column 4- Post monsoon Ground water quality
Column 5- Constituents analyzed
Column 6- Anomalous constituents
Column 7- Remarks

24. GWQ Data – Stages of quality evaluation
Organized Legacy data
excel tableAnalysis,
Interpretation &
Organization Ground water quality
point data layer
Legacy GWQ data
Fresh GWQ data Lat-
Long data
Satellite Data
Settlement data
Intermediate
outputs
Interpolation
using statistical
method
Element-wise ground
water quality layers
Ground water
quality point data
layer
Intermediate
outputs
Integrated ground water
quality layers
Element-wise
ground water
quality layers
Grouping &
Intersection of
layers
Intermediate
outputs
Ground water quality
map (corresponding to
1:50,000 scale toposheet)
Integrated GWQ
layers, Base map
layers
Final
output
Validation, Map
composition &
Clipping
Quality checking - 2
Quality checking - 3
Internal Team
Internal Team
External Team
External Team
Quality checking - 1Internal Team External Team

25. Ground water quality map (shallow depth zone)
corresponding to 1:50,000 scale toposheet

26. Thank You!