Bhubaneswar, Sep 15 (IANS): Floods in Orissa that have killed at least 22 people and affected more than two million over the past week could have been avoided had the authorities been cautious in releasing water from the Hirakud dam, experts say.

Heavy rains and the release of huge quantity of water from Hirakud reservoir have wrecked havoc in about 4,000 villages in more than half of state's 30 districts, mostly located on the downstream. At least 24,429 houses have been damaged.

The Hirakud dam, built across the Mahanadi river, about 350 km from here in Sambalpur district, is one of the longest in the world.

Although it is one of independent India's early multipurpose river valley projects, the primary aim of the dam is to control flood in the downstream areas.

This year, it opened 59 gates, 39 out of which were to be opened within a span of 48 hours, to release excess water it received from upper catchments areas.

This sudden release of so much water was easily avoidable, activists say.

"The release of huge amount or water could have been avoided had the authorities had kept less water in the dam," Ranjan Panda, convenor of Water Initiatives Odisha, a network of civil society organisations, told IANS.

The state government says the flood was caused by the heavy rain at the upper catchments area of the dam and release of water from Chhattisgarh.

But activists counter that authorities should have kept releasing water at regular intervals from the dam, keeping the climatic conditions and rain forecasts in mind.

"There has been a change in the rainfall patterns due to climate change and other factor which has made the 'Rule Curve' that was devised in 1988 obsolete.

"It's time the government revisits this and establishes sound scientific mechanisms to co-ordinate with the upper basin state of Chhattisgarh as well as with the India Meteorological Department," Panda added.

The full reservoir level at the dam is 630 feet. As per the prescribed guideline, the water level at the dam should have been kept at 590 feet Aug 1, but this year, it was as high as 607.27 feet during that period, Panda said.

The water levels were at consistently high levels throughout the season, he said.

"The severity of the ensuing flood was especially due to mismanagement of the Hirakud dam, and it called for urgent attention of the policy planners," Panda said.

However, state Revenue and Disaster Management Minister Suryanarayan Patro said all prescribed rules were followed.

"The dam engineers take measures as per the prescribed guidelines," Patro told IANS.

But his reply has no takers in the opposition.

"The government's motive was to store water for the industries," said Bijoy Mohapatra, Bharatiya Janata party (BJP) leader and former state water resources minister.

"The flood was man made. Had the government acted on time, the floods could have been averted," state Congress president Niranjan Patnaik said.

The total allocation of water to the industries from the reservoir was 3,191,200 gallons per year before 1997, says a recent study by Rajkishor Meher, a reader in sociology at the government-run Nabakrushna Choudhury Centre for Development Studies.

"This has increased by 27 times in the past nine years," the study added.

"The government has been keeping the reservoir water at higher level deliberately to supply water to industries in case of a monsoon failure," farmer leader Saroj said.