What looks like a gargantuan, half-buried oyster shell west of Midtown could be a sparkling, life-sustaining water source for Atlanta within the next two and 1/2 years.

Atlanta Department of Watershed Management officials tell 11Alive that testing has begun this week for a tunneling project that will transform the Beltline-connected Bellwood Quarry into a deep, 30-day water source for the city. The current backup water supply is just three days.

Funded by the municipal option sales tax approved by voters last year, the roughly $300 million project will begin in September, linking the quarry to the Chattahoochee River via a five-mile tunnel. The big dig should be finished by the end of 2018, providing 2.4-billion gallons of reserve H2O, the TV station reports.

Once that's finished, officials plan to turn their attention toward making the surrounding 300 acres into a recreational utopia 30 percent bigger than Piedmont Park.

If the vision pans out, this new lake would be the centerpiece of the mother of all Beltline greenspaces, Westside Reservoir Park, a collection of meadows, hiking and biking trails, and some active uses such as baseball fields.

As one Curbed Atlanta poll after the next has proven, Atlantans are extremely supportive of this project becoming reality. Because unless you're filming zombie shows, anything beats that massive Westside gash.