Great success in cleaning up the river Thames. Many species of fishes have returned.
London’s river Thames from Gravesend to Teddington Lock was so polluted in 1957 that not a single fish could have lived there before. This stretch of the Thames is 43 miles (69 km) long.
In the earliest centuries the Thames was thriving with fish. In the estuary were saltwater fish in abundance and in the upper reaches salmon spawned in the shallow water.
The problem started when the city grew bigger and all the rubbish was thrown into the river. Then came more pollution and more seriously, when in 1800 the water closets became widely spread and the sewage was going untreated into river. As before the city sewage was kept in cesspits and spread onto market gardens.
When untreated sewage went into the river it made the bacteria grow and depleted slowly but surely the water of oxygen which is vital for plant and fish life.
In the mid 19th century the stench from the river was so great that the House of Parliament, which is right on the river’s edge, had to soak the curtains with disinfectant.
They built great sewage works in the North of London and in the South which should have coped and prevented the pollution. The problem was gas and chemicals works spilled their waste water into the river which made it worse. The oxygen level went even further down.
In the 1960 they began a major conservation program and modernised London’s sewage treatment plants. It also improved the waste water of the industries.
After that you could see fishes return to the river and in 1973 there were roach, bream, salmon and Dover sole. All in all they found 72 types of fish in the river Thames. You could catch eels in the middle of the city. Herons returned, flocks of duck fed on green plants, waters and cormorants were patrolling the water’s edge.
However, despite of the great success conservationists are still asking for further improvements. They suggest banning weed killers and higher quality of water released from the sewage treatment works, higher control of industry’s waste water and the run-off from roads which still contain toxic chemicals. They demand for the river to be so clean for the people to bath in.