But the fight for the dam, the biggest in Syria, forced it out of service on Sunday, risking unsafe rising water levels.
The hydroelectric power plant on Tabqa dam has stopped working after the control unit of the station was damaged as a result of either artillery shelling or air raids, Al-Mayadin TV channel reports.
The ongoing clashes at Tabqa dam have damaged its power station, forcing a halt to operations on Sunday, risking unsafe rising water levels.
Mohammed Khedhr, of Sound and Picture Organisation, which documents IS violations, confirmed that battles are taking place inside Karama, about 10 miles east of Raqqa.
US-backed Syrian rebels are trying to capture Raqqa from IS. The US military shared aerial photos of the dam on March 26, reporting that the "Tabqah Dam has not been structurally damaged to our knowledge and the Coalition seeks to preserve the integrity of the dam as a vital resource to the people of Syria".
The U.S. has deployed more than 700 advisers, Marines and Rangers to Syria to support fighters battling Islamic State.
Other Kurdish activists said that the SDF has reached the strategic Tabaqa Dam in the western countryside of Raqqa following battles with the IS militants.
The push toward the Tishrin Dam came three days after USA aircraft ferried Syrian Kurdish fighters and allies behind ISIS lines to spearhead a major ground assault on the IS-held town of Tabqa where the dam is located.
But it warned that damage to the dam "could lead to massive scale flooding across Raqqa and as far away as Deir Az-Zour" province to the southeast.
An offensive to recapture the Syrian city of Raqqa from Daesh will start in the coming days, French Defense Minister Jean-Yves Le Drian said Friday.
Fears that a nearby dam might collapse are reportedly causing panic and confusion in the Syrian city of Raqqa, a stronghold of the so-called Islamic State (IS) group.
The UK-based Syrian Observatory for Human Rights said coalition airstrikes have killed at least 89 civilians over the past week. Meanwhile, the latest round of United Nations -backed Syria peace talks entered a second day in Geneva on March 24 but there was little hope of a breakthrough in negotiations that have yielded little in previous rounds.
Le Drian spoke on CNEWS television Friday.
Earlier in the day, Kurdish officials said the battle against Raqqa city will start early next month. The talks come amid a recent escalation in fighting in Syria, notably in and around Damascus.
"It will be a very hard battle, but a battle that is going to be of utmost importance", he added.
Some 700 US military advisers, Marines, and Rangers have entered Syria to support fighters battling IS militants.