Lending their political might to the agitation, the four JD-S MLAs and an MP submitted resignations to H D Kumaraswamy to protest the BJP government's action to release water complying with a Supreme Court order.
Authorities said they have decided to deploy RAF to assist police in the wake of escalating protests.
More than 100 people were arrested at Gejjalagere in Mandya district, the hotbed of Cauvery politics, when they blocked the Shirdi express train, police said.
Protests continued in Mysore, Chamarajanagar and Mandya, the Cauvery basin districts. Vehicular movement on the Bangalore-Mysore road was hit for the third day, police said.
JD-S Lok Sabha member from Mandya N Cheluvarayaswamy and its four MLAs from Mandya district -- Kalpana Siddaraju, C S Puttaraju, M Srinivas and A B Ramesh Bandisidddegowda submitted their resignation letters to Kumaraswamy.
Speaking to reporters here, Kumaraswamy said a meeting of party MLAs and MPs has been convened tomorrow to decide the future course of action, including whether all its legislators should quit en masse.
JD-S, which draws its core strength mainly from the Cauvery belt, has 26 MLAs and three MPs in the state.
Criticising the BJP government for releasing Cauvery water to Tamil Nadu when its farmers are facing acute shortage, Kumaraswamy said, "Our party has decided that MLAs from Mandya district will quit".
Former Prime Minister and JD-S chief H D Devegowda has sought an appointment today with Prime Minister Manmohan Singh to explain the hardship faced by people of Cauvery basin.
Bowing to the Apex Court order, Karnataka began releasing water from Krishna Raja Sagar and Kabini dams early yesterday to ensure flow of 9,000 cusecs.
Defending the decision, Chief Minister Jagadish Shettar said on Sunday it was "inevitable" to honour the court order, but the state was committed to protect farmers' interests.
He had also said government would file a petition before the Supreme Court, seeking a review of its order asking the state to honour the September 19 Cauvery River Authority directive to release 9,000 cusecs to Tamil Nadu till Oct 15.
Karnataka has already urged Prime Minister, who is also the CRA Chairman, to review its Sept 19 order and keep it in abeyance till the decision was reviewed.
Bangalore: Protests against release of Cauvery water to Tamil Nadu continued for the second day Monday with authorities deciding to deploy Rapid Action Force to maintain peace in Mandya, the epi-centre of the stir, even as four JD-S MLAs and an MP submitted resignations to the party state unit chief to protest the government action.
First Published: Monday, October 01, 2012, 11:56