Now efforts are being recalibrated to the city's west bank - where, as has been widely reported, the challenges that coalition forces will likely face are unique.
The city of Mosul is severed from north to south by the River Tigris, and its western half is far more densely populated than its east - rendering the potential for civilian casualties much greater. The west is also home to the narrow streets of the old city, and tightly packed housing will reduce the advantage of the government's armoured vehicles and tanks, not to mention their air power.
Both of these were indispensable advantages in the city's east.
Before any real efforts can be made to recapture the remainder of the city, Iraqi forces must first deal with the river itself. A combination of coalition airstrikes and IS vandalism has left all five of the city's bridges inoperable.
|Every night they are coming in boats, sometimes dozens, on suicide missions. Normally we get them before they reach our side of the river, but not always|
Recent days have seen the Iraqi army begin construction of several floating bridges, while heavy hardware has also been moved to the southern town of Qayarrah in anticipation of an assault on west Mosul from the south.
As it stands, Iraqi government troops have also taken up position along the river's east bank. But the natural barrier the river serves as has done little to reduce the danger posed to the army's 16th division by IS militants.
"Every night they are coming in boats, sometimes dozens, on suicide missions. Normally we get them before they reach our side of the river, but not always," warns Colonel Nazer Tahir of the division's 75th Brigade.
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|Attending to the corpses of IS fighters puts Iraqi soldiers at risk from snipers on the west bank of the river [Gareth Browne]|
He looks out towards the river from the rooftop of a house which now serves as his unit's forward-most position.
This fortified post sits just south of the city's now disabled fourth bridge, in the al-Ba'ath neighbourhood. It has had some very close calls - just days ago a ground floor window was shattered by an IS-launched RPG. Nobody was hurt.
The bodies of IS fighters who succeeded in sneaking across the river can also be seen lying little more than 20 metres from the house.
Despite the entire east bank having been officially declared "liberated", there remains a 600m stretch of no-mans-land between this house and the Tigris.
This boggy stretch is well within the range of the many IS snipers on the river's west bank, preventing Iraqi soldiers from pushing right up to the shoreline. Since losing control of the city's east, IS has taken to launching daring, even suicidal, night-time raids across the river under the cover of darkness.
Small boats packed with as many as a dozen fighters try to cross the river at its narrowest point, but most are picked off by the army's gunners who are on constant look out.
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|Iraqi soldiers must attempt to spot IS fighters navigating
through this maze of buildings on the east bank of the Tigris [Gareth Browne]
In the street below the rooftop lies the rotting corpse of an IS fighter who attempted a suicidal attack a few days ago.
He made it further than most, making it across the river and to within just meters of this army position. But he too was eventually gunned down. The river bank is littered with the corpses of fighters who have done just the same, and even if Iraqi troops were willing to bury the jihadists - which is far from certain - they lie in open ground that would likely expose troops to a barrage of sniper fire.
IS is not the first jihadist group to attempt to use boats for such attacks. In 2000, al-Qaeda in Yemen launched an attack with a small fishing skiff against the USS Cole, an American destroyer docked in Aden.
Captain Amar Abdul-Sa'ad tells The New Arab that "no sane or sober person would get on one of those boats". His men claim that the IS fighters attempting to cross are often under the influence of drugs. "They take pills before they leave to get high, that way they don't realise the danger," said one soldier.
|If we shoot the vest, it takes out the whole boat|
Is it surprising that, despite being pushed back on a daily basis, IS continues to launch such aggressive attacks?
"Of course, they are desperate to reclaim the initiative," said Colonel Nazir. "They want to be in control, but everyone can see that they are not."
Nazir added that many of the fighters who try to sneak across are wearing suicide vests. "This makes it easier for us; if we shoot the vest, it takes out the whole boat."
A recent lull in fighting means that much of this brigade's time is spent staring across the river through rifle scopes, awaiting an attack that could come at any moment. Or with their necks craned, keeping an eye out for weaponised drones high above.
Some reports suggest that the 16th division will be used only as a holding force in recently liberated neighbourhoods. With all that in mind, I ask Colonel Nazir one final question. Are his men ready to cross the river?
"We are ready to take back Mosul," he replies. "We are ready to cross the river, we are just waiting for the order."
Fixing and translation services provided for this report by Halan Shekha.
Gareth Browne is reporting from the front lines in the battle to retake Mosul from the Islamic State group. Follow him on Twitter: @BrowneGareth