Join the Tharavai Restoration Campaign • Preserving Heritage Landscapes & Biodiversity • Community Action & Ecological Revival
Then and Now
A survey map from about 1920 shows a continuous Tharavai behind the coast; today's satellite pictures show most of that belt dry. We traced the old belt and laid it over present-day imagery.
1920 survey map
Continuous Tharavai
A survey map from about 1920 shows a continuous Tharavai behind the coast.
Today: satellite image with the 1920 belt traced
Dry, and much of it under salt pans
Red shows salt pans inside the 1920 belt: about 855 ha in all, covering 95% of the belt at Periyasamipuram and 41% at Vembar. Most of the rest of the belt is dry.
Five findings
What the map comparison shows
We traced the old belt and laid it over present-day imagery.
1)
The 1920 belt
In 1920, the belt covered about 13 sq km (about 1,260 ha) between Periyasamipuram and Mookaiyoor, and about 65 sq km along the whole coast including the Valinokkam lagoon.
2)
Salt pans on the old belt
Near Periyasamipuram and Melmandai, rectangular pans, most likely salt pans, now sit on and beside the old belt.
3)
A narrow wet channel
North of Kannirajapuram, only a narrow wet channel remains where the 1920 map shows a much wider belt.
4)
No visible standing water
Near Narippaiyur and Mookaiyoor, the old belt holds no visible standing water.
5) Valinokkam
Salt works in the lagoon
At Valinokkam, the 1920 lagoon is now largely taken up by salt works.
Note
11 shared points
Map alignment
The 1920 map was fitted to today's coordinates using 11 shared points; positions are accurate to roughly 300 m to 1 km.
Satellite imagery
Different dates
Satellite imagery is a mosaic of different dates; findings will be checked on the ground and after the northeast monsoon.
3.2M m³