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Table 1 Theme wise features, ranking & weightage

From: Identifying groundwater recharge zones using remote sensing & GIS techniques in Amaravathi aquifer system, Tamil Nadu, South India

Theme

Features

Rank (in words)

Rank (in number)

Weightage

Geomorphology

Pediments-moderate

Moderate

2

15

Pediments-deep

Moderate

2

Pediment-shallow

Low

1

Dissected plateaus

Very low

1

Valley fills

High

3

Bazada zone

High

3

Landuse/Landcover

Settlements

Low

1

10

Barren land/rocky

Low

1

Fallow land

Moderate

2

Water body

High

3

Plantation

High

3

Forest

Moderate

2

Vegetation

Moderate

2

Wet lands

High

3

Soil

Clayey soil/loam

Low

1

10

Silty soil

Low

1

Red soil

Moderate

2

Lateritic soil

Moderate

2

Gravely soil

High

3

Sandy loam

High

3

Slope (%)

<  3

Nearly levelled/Very gentle

3

15

3 to 5

Gently sloping

3

5 to10

Moderate

2

10 to 15

Moderate to steep

2

>  15

Very steep

1

Post monsoon groundwater level

<  3 m bgl

No space – low

1

15

>  3 & < 6 m bgl

Moderate

2

>  6 & < 9 m bgl

High

3

>  9 m bgl

Very high

3

Geology

Charnockite

Low

1

10

Granitic gneiss

Low

1

Banded gneissic complex/Banded migmatite

Low

1

Highly weathered granitic gneiss

Moderate

2

Alluvium

High

3

Drainage

Other regions

Low

1

10

Drainage lines

High

3

Weathering

>  6

Low

1

15

6–10

Moderate

2

10–20

High

3

>  20 m

Very high

3

  1. bgl – below ground level