A new rock ramp on the White River is helping to provide adequate water supply to the White River Water Treatment Plant after the failure of the Emrichsville Dam, just south of 16th Street, in fall 2018.
Prior to the failure of the low-head dam, Citizens Energy Group had begun building a water intake structure near 33rd Street along the White River as a complement to another project further upstream—a floodgate on the Central Canal near 56th Street.
Before the intake was constructed, water only reached the White River Water Treatment Plant by flowing all the way down the Central Canal from just north of 63rd Street to the plant near 16th Street.
The occasional closure of the floodgate (to prevent flooding in the Broad Ripple and Warfleigh neighborhoods) would shut off water supply to the White River Water Treatment Plant, necessitating an intake structure farther downstream to move water from the river to the canal to reach the treatment plant.
The intake’s reliance on the Emrichsville Dam to create a pool of water to feed into the structure required the dam to be replaced. A rock ramp was chosen as the solution because it mitigates the primary risks associated with a traditional low-head dam, which blocks the river and vertically forces it to flow over the top of the dam.
A rock ramp is constructed by placing large limestone boulders (organized in arches across the river) on top of a constructed crushed limestone ramp to form a stepped structure that holds back the water to form an upstream pool.
With a slope less than a sidewalk ramp, the rock ramp is much safer than the Emrichsville Dam, which was a 9-foot-high wall across the river. To further enhance safety, signs posted upstream of the rock ramp direct people in watercraft such as canoes and kayaks to exit the river and follow a newly constructed stone path around the structure, which is not designed for navigation.
Unlike a low-head dam, the ramp also enhances the ecology of the river by allowing fish and other aquatic life to move through the structure.
Construction of the White River Rock Ramp, located about a mile north of the original dam, was completed in October, a month earlier than projected, and restored a large percentage of Lake Indy, a body of water used by community members.
“Teamwork played a critical role in the success of this project,” said Matt Thomas, Director, Plant Engineering. “After 20 meetings with various stakeholders, we came to a compromise with the design and location, and we are pleased that the rock ramp is functioning as planned and is proving to be mutually beneficial for Citizens and our customers.”
