How is urbanization impacting our water bodies

A conceptual depiction

Catch2water.blogspot.in

Forested Catchment

Forested Catchment

River

WATER TABLE

WATER TABLE

UndergrowthHumusRunoff slows down

Precipitation does not exceed infiltration

Precipitation does not exceed infiltration

Precipitation is slowed down, helps infiltration

WATER TABLE IS RECHARGED

Precipitation is slowed down, helps infiltration

UndergrowthHumusRunoff slows down

WATER TABLE IS RECHARGED

Soil pores gradually fill up helping infiltration

Soil pores fill up much more slowly and infiltration continues

Soil pores fill up and runoff is generated

Soil pores fill up much more slowly and infiltration continues

RunoffUndergrowthHumusRunoff slows down

WATER TABLE IS RECHARGED

Moderate Runoff generation

Moderate Runoff generation

Higher ground water recharge which gradually flows towards the water body

Higher ground water recharge which gradually flows towards the water body

WATER TABLE

Moderate Runoff generation

Moderate Runoff generation

Higher ground water recharge which gradually flows towards the water body

Higher ground water recharge which gradually flows towards the water body

GRADUAL RISE IN RIVER

WATER TABLE GETS RECHARGED

Maintains base flow in River even during

summers

WATER TABLE

Subsurface water gradually flows towards the water body even months after rains

Subsurface water gradually flows towards the water body even months after rains

URBANIZED SCENARIO

TREE COVER IS REMOVED

WATER TABLE

WATER TABLE

Undergrowth is removed

Soil compacted, covered with roads,

pavements

WATER TABLE IS DEPLETED

Deep pumps drain out water and

reduce the water table

Limited water table recharge

Limited infiltration

Almost Immediate runoff generation

Limited percolation

WATER TABLE

Low groundWater flowLow ground

Water flow

High runoff and artificial drainage

from the city

High runoff and artificial drainage

from the city

WATER TABLE

Low groundWater flowLow ground

Water flow

High runoff and artificial drainage from the city leads to sudden swelling

of river and flooding

WATER TABLE

Low groundWater flowLow ground

Water flow

The runoff drains faster and lesser

water is left in the river

WATER TABLE RECEEDS

Low groundWater flowLow ground

Water flow

With no groundwater flow to recharge the river in summers, the river dries out