Why Yamuna withdrawing from Delhi streets so slowly?

The Yamuna’s water levels are steadily dropping, but this hasn’t made much of a difference to the flooded Delhi streets. Yamuna’s water level was 206.14 metres on Sunday morning, down from a height of 208.66 metres at 8 o’clock on Thursday.
However, a barrage on the Yamuna with some clogged flood gates and late evening showers has stolen the respite from flooded streets, submerged homes, and swamped historical landmarks.
Roads near the Rajghat Memorial and Delhi’s busiest intersection, ITO, are still clogged with traffic, making it difficult for commuters to move through.
The Indian Navy managed to open one flood gate of the barrage on Friday, with four of the 32 gates still jammed.
The officials had to stay on their toes for two days due to a damaged drain regulator near the Supreme Court. The breach led to flooding outside the Supreme Court and the iconic Rajghat.
Army and emergency workers were able to close the break, but Saturday evening’s showers only made the water levels in the city rise.
To prevent water from flowing into the city, we have created a wall by stacking up sacks, said Saurabh Bharadwaj, Delhi’s flood control and irrigation minister.
Chief Minister Arvind Kejriwal has said that the Yamuna is retreating gradually and that everything will return to normal soon if there is no more heavy rain. However, he added that the flood threat is not over yet.
Thousands of people were relocated from low-lying locations to emergency shelters set up in schools and other buildings