Tunnel construction delayed in flood-prone Ellicott City, storage pond set to open

Vehicles stuck in mud being removed, loaded on flatbed trucks. pic.twitter.com/VF1d3gBLuH
— Neal Augenstein (@AugensteinWTOP) May 28, 2018

Vehicles that were stuck in the mud are being removed and loaded onto flatbed trucks. (WTOP/Neal Augenstein)

Heavy machinery scooping up mud off Fels Lane, near Ellicott Mills Drive. pic.twitter.com/Ze24G4TEgD
— Neal Augenstein (@AugensteinWTOP) May 28, 2018

Dump trucks are scooping mud off Fels Lane, near Ellicott Mills Drive after the flooding in Ellicott City. (WTOP/Neal Augenstein)

Some homes in Ellicott City are built over waterways. This home on Main Street has the Tiber Creek flowing beneath it. (WTOP/Neal Augenstein)

This image made from video provided by DroneBase shows damage by floodwaters near the intersection of Ellicott Mills Drive and Main Street in Ellicott City, Md., Monday, May 28, 2018. Howard County Executive Allan Kittleman said Monday morning that his priorities are finding a missing man and assessing the condition of buildings that house shops, restaurants and families. (DroneBase via AP)

Water moves past a car swept into the riverbank and smashed by a fallen tree is shown just off Main Street in flood-ravaged Ellicott City, Md., Monday, May 28, 2018. Sunday’s destructive flooding left the former mill town heartbroken as it had bounded back from another destructive storm less than two years ago. (AP Photo/David McFadden)

AP Photo/David McFadden

Residents gather by a bridge to look at cars left crumpled in one of the tributaries of the Patapsco River that burst its banks as it channeled through historic Main Street in Ellicott City, Md., Monday, May 28, 2018. Sunday’s destructive flooding left the former mill town heartbroken as it had bounded back from another destructive storm less than two years earlier. (AP Photo/David McFadden, file)

AP Photo/David McFadden, file

A car that was swept into the riverbank rests just off Main Street in flood-ravaged Ellicott City, Md., Monday, May 28, 2018. Howard County will reopen the closed stretch of a road leading to Main Street on Friday. (AP Photo/David McFadden) — A car that was swept into the riverbank rests just off Main Street in flood-ravaged Ellicott City, Md., Monday, May 28, 2018. Sunday’s destructive flooding left the former mill town heartbroken as it had bounded back from another destructive storm less than two years ago. (AP Photo/David McFadden)

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Groundbreaking has been delayed for the largest and potentially most effective aspect of a $167 million plan to minimize flooding along Main Street in Maryland’s historic Ellicott City.

In May 2022, Howard County Executive Calvin Ball announced the county had secured funding to build a 5,000 foot-long tunnel to carry water away from Main Street and into the Patapsco River. The county signed a $75 million Water Infrastructure Finance and Innovation Act Loan with the U.S. Environmental Protection Agency to pay for the tunnel.

In announcing the funding, Ball said he expected the tunnel design would be completed by the fall of 2022, and that ground would be broken before December 2022.

WTOP has learned the design for the project, known as the Extended North Tunnel, is expected to be completed within the next month. At this point, the county has not provided a new target date for groundbreaking.

When it’s completed, the 18-foot-diameter tunnel will carry about a swimming pool’s worth of water every second. The tunnel running parallel to Main Street will be, at points, up to 100 feet below ground level.

Water will enter the tunnel in at least two locations — the primary intake structure located on the north side of the 8800 block of Frederick Road, and one in the vicinity of current Parking Lot F near the intersection of Ellicott Mills Drive and Main Street. The flood-swollen Tiber Creek washed away a portion of Ellicott Mills Drive in 2018, which resulted in a sturdier, larger concrete waterway beneath the road.

Ellicott City experienced two “thousand-year storms” in 2018 and 2016 that devastated parts of the city’s historic downtown.

With a multimillion-dollar project, requiring local, state, and federal approvals, delays in the start of construction are common.

Another component of the county’s Ellicott City Safe and Sound Plan — the Quaker Mill flood mitigation pond — is slated for a ribbon-cutting in February, according to a spokesman for Ball.

Ground was broken in December 2021 for the project, which will provide approximately 10-acre-feet of storage, which is the equivalent of nearly 3.3 million gallons of water. Located upstream of downtown Ellicott City, near a subdivision, the pond is located at the intersection of Rogers Avenue and Patapsco River Road.

In October 2022, Ball cut the ribbon on another retention pond uphill from downtown Main Street. Dubbed the H-7 pond, it was constructed on state land in a cloverleaf interchange at the intersection of Route 29 and Route 40/Baltimore National Pike.

Shortly after Ball took office in 2018, the Department of Public Works began developing short-term and long-term projects and procedures, to reduce the risk from flooding in the former mill town.

Emergency sirens were installed in 2019 to provide warning to residents and business owners of flash flood warnings. After a July 2019 incident, in which emergency sirens didn’t sound, the county and National Weather Service implemented a new protocol to differentiate “Historic Ellicott City” from the wider city.