This is due to extraction of sand and boulders from these streams.

Snow fed streams across the Kashmir valley are facing the threat of extinction as there is a lot of extraction of sand and boulders from these streams, especially during the autumn and winter season when the water levels are very low.
Recently, one of the prominent trout streams near Kokernag suddenly disappeared after a massive sinkhole swallowed the stream, triggering panic among the locals and also among the people living in the low lying areas of the stream.
This snow fed stream of Kokernag is known as Brengi Nallah and is famous for trout angling as during the summers hundreds of anglers including from Europe used to for the trout angling in this stream.
“Thousands of trout fingerlings have perished as the Brengi Nallah due to the sinkhole is now dry downstream. It has caused huge damage to aquatic life and has endangered even the farming in the low lying areas for the summers,” said Abdul Rahim Dar, one of the residents of the area where the sinkhole has swallowed the stream.
The district administration of Anantnag in South Kashmir has enforced restrictions in the area and has also appealed to the media not to be close to the sinkhole while reporting for the news channels as it can endanger their lives.
Locals and reporters who visited the area said that due to the death of this snow fed stream, thousands of trout fish have died as more 20 km long stretch of this Nallah in the Anantnag district has dried up. Hundreds of villagers in this stretch of the Nallah are worried about drinking water and also about the irrigation of their land as it is the only source available to them for drinking water and for the irrigation.
According to scientists and experts, such sinkholes are believed to have been caused by the chemical dissolution of limestone rocks in the river bed. Piyush Singla, Deputy Commissioner Anantnag in South Kashmir, told the media that the government will try to restore the stream on scientific lines and are in touch with experts. He has appealed to people not to be close to the sinkhole and also not to panic as the government will take all the steps to restore this snow fed stream.
Villagers are worried that the water which is going down into the sinkhole may reappear with force in any low lying village of the stream and it can spell disaster. It is in place to mention that Kashmir valley has a lot of snow fed streams and many of them are coming from the Himalayas, especially in South Kashmir.
Lidder stream, Brengi stream and Rambi Ara are some of the streams which are facing lot of threat to their existence and biodiversity due to the fact that the J&K government has recently given these contracts of sand and boulders extraction to the contractors from outside at the high bids and they have started extracting sand and boulders without adhering to the norms.
A few days back in Sogam village of Chadoora in Budgam district, people came out on the roads and protested against the authorities for allowing heavy extraction of sand and boulders from Doodh Ganga Nallah, a snow fed stream coming from Peer Panchal Range and passing through the backyard of tourist resort of Yousmarg. The protesters have appealed to the government to protect this stream as a lot of water supply schemes and the irrigation of hundreds of villages is dependent on Doodh Ganga Nallah.