The Tabqa Dam is largest dam in Syria and its located on the Euphrates river, 40 kilometers West from city of Raqqa in Raqqa Governorate.
Nearest city to the dam is Al-Tabqa and its located South of the dam itself.
During the Syrian Civil War on 11 February 2013 the dam was captured from government forces by the Opposition fighters, and during the late 2014 Islamic State took control of the dam facilities.
In late January 2017 Kurdish-Arab alliance known as Syrian Democratic Forces (SDF) started advancing toward Tabqa dam facilities. During that time ISIS started threatening that it will open floodgates, hoping to stop SDF advances or at least slow them down.
On 26 March SDF confirmed that they managed to capture most parts of the dam from ISIS, the dam itself was reported to have become inoperable.
ISIS claims of structural damage:
During the 26 March ISIS media accounts released 4 statements claiming that Tabqa dam was at risk of collapse amid United Stated Coalition heavy bombardment.
First statement: Source from Services Diwan: Euphrates Dam near Tabqa, west of Raqqah, out of service, all flood gates closed, due to heavy American aerial and artillery bombardment.
Second statement: Source to Amaq: Euphrates / Tabqa Dam stops activity due to severance of the main electrical feed, bringing all equipment and dam sections completely out of service.
Third statement: Euphrates / Tabqa Dam threatened with collapse at any moment due to American airstrikes and great increase in water levels confined by the dam.
Fourth statement: Services Diwan not able to send maintenance teams to Euphrates / Tabqa Dam due to heavy American bombing on the area.
Later that day ISIS released image of Tabqa Dam control room claiming that it was allegedly destroyed in US Coalition air strike.
Image posted above show that whole room is destroyed completely. Black trails on the walls and the traces on the metal are consistent with intense fire and smoke inside the room.
During the evening of 26th March US @CJTFOIR released drone footage of Tabqa Dam.
On the images Tabqa Dam Hydro-electric turbines are intact and no traces of air strikes can be found (green mark). On the two control towers damage is noticeable, mainly fire and smoke traces going up to from the Northern tower and part of the roof panels seems to be missing on both towers. Perfectly rectangular shape suggest that they were removed or hit directly and collapsed. (red marks).
Satellite imagery provided by Digital Globe and posted by @EliotHiggins from March 23rd 2017 clearly show that no damage at the dam and control towers is noticeable.
Another satellite imagery from March 24th 2017 of the Northern control tower shows no damage at all. That suggest that the damage on towers happened between 24th and 26th March.
Former head of Tabqa Dam confirmed to the @Dalatrm , BBC Foreign News Producer, that control rooms are indeed located in two towers. Details of the conversation with former head of dam can be found in Dalati thread.
United States led coalition air strikes confirmed:
During the evening of 27 March ISIS released new drone footage of the dam and more video footage inside. From drone footage its noticeable that control towers were hit at least 4 times in total.
Footage from the inside shows small diameter hole on the ceiling, this one would match with the one just next to collapsed panels.
Remnants of the first projectile found beneath the small diameter hole looks quiet intact, mostly burned and with scratches on the side, also no traces of shrapnel marks are found on the wall.
Another, second projectile is also shown, again mostly with burn marks, no shrapnel marks on side walls.
Further investigation shows that second projectile back side matches with BLU-109 hardened penetration bomb. Left image is from strike in Libya. Both remnants look the same, but damage is much less on image from Syria (right one).
Back part of the first projectile shown in the video also matches with BLU-109 hardened penetration bomb.
Now it is possible to confirm that control towers are indeed hit multiple times by what is very likely to be a BLU 109 hardened penetration bomb. There are three possible scenarios that would explain damage inside.
First scenario: BLU-109 hardened penetration bomb filled with concrete instead of explosive, used many time when targets are located in highly populated areas to minimize damage from explosion. Fire could occur from old Soviet electronic components that was located inside control room. This scenario would explain why missiles look undamaged.
Second scenario: Thermobaric explosive filler variation on the BLU-109, which would explain huge fire that occurred inside the room, but not the intact missiles. Missile would be largely destroyed or severely damaged.
Third scenario (worth mentioning but highly unlikely): BLU-109 version called HAMMER which is filled with dozens of Kinetic Fireballs Incendiaries (KFI) (not explosions). These spread around the bunker and burn with high intensity. Details on this variant are not widely available, and its not even known is this version currently in use or still in development.
On 28 March it was reported and later confirmed that Director of the Tabqa dam Ahmed Al Hussein was killed in coalition strike while trying to inspect the dam. He was filmed in ISIS video just day before.
GRAPHIC IMAGES BELOW: Director of the Tabqa dam Ahmed Al Hussein.
Water level at the Tabqa Dam:
While most people were busy trying to find damage on Tabqa Dam structure, it is also worth mentioning the water level at the dam. Latest source for measuring the water level is ISIS video containing drone footage, released on March 27.
On the image below, which i will use as a reference image, we see details of Tabqa dam floodgate. Floodgates are adjustable gates used to control water flow and reduce pressure from accumulated water on dams so the dam would not overflow and cause damage on the structure of the dam itself.
Floodgates are usually controlled from the dam control room and most of them have manual control system in case there is an emergency and if they cant be operated from control room.
Another emergency water release system / irrigation channel on Tabqa dam is Northern spillway know as Al-Rai channel intake. Spillways ensure that the water does not overflow by releasing water in controlled small amounts into a downstream area.
From further investigation using drone footage and reference image of dam floodgate it is possible to determine approximate water level at Tabqa dam.
While the water level is high it did not reached alarming height yet, but the situation is still dangerous mostly because control room is destroyed. Currently only option for controlling the water level is to release it trough Northern spillway (controlled by SDF).
Former Head of Tabqa dam confirmed to @Dalatrm that there is a way to operate floodgates from the engine and turbine room deep below inside the dam, if control room suffers catastrophic failure.
When more evidences became available article will be updated.