Ellicott City Flood is Nothing New | WYPR

Ellicott City Flood is Nothing New

Jun 1, 2018

This map of the Tiber Branch Watershed shows how the streams affect Ellicott City
Credit Howard County

The flood that ripped through Ellicott City last Sunday, destroying homes and businesses and claiming one life was devastating. But it wasn’t anything new. Ellicott City has had a long history of floods.

In fact, the first grist mill, built by James Hood in 1766, was destroyed a mere two years later by one of the earliest recorded floods.

The town flooded again in 1817 and 1837. And then there was the flood of 1868 that killed 43 people and destroyed 14 homes.

There were eight floods in the 20th century, including the flash flood of 1952 that sent an 8-foot wall of water roaring down Main Street and the flood caused by Tropical Storm Agnes in June of 1972. That one dropped 10 to 14 inches of rain on already soaked lands and caused major flooding from North Carolina to New York State and killed seven people in the Patapsco Valley.

In this century, the town flooded after Tropical Storm Lee in September 2011 and after what was then called a once in a thousand years storm two years ago. Witnesses said this one was worse.

It’s not hard to see why Ellicott City is so vulnerable to flooding. It sits in the valley of the upper Western Branch of the Patapsco River close to the mouths of four of that river’s tributaries—Tiber Branch, Hudson Branch, Autumn Hill Branch and New Cut Branch.

A February 2018 report from the Army Corps of Engineers says the location "at the convergence of these waterways, the topography, and stormwater runoff contribute to significant flood events within Ellicott City and particularly the historic district."

Chris Brooks, a senior water resources engineer with McCormick Taylor, the firm that did a hydrologic study for Howard County after the 2016 flood, says the lower Main Street section of town "has a lot of things working against it to keep high and dry."

And the fact that there are "bedrock hills that rise very steeply right off of Main Street," doesn’t help either, he added. "When there is heavy rain fall, it is always going to funnel through that point of town."

The study, part of an $84 million watershed master plan, recommended that the county create storage ponds throughout the flood zone to hold water, underground pipe farms and storage vaults to draw water away and store it and stabilizing and expanding stream banks to slow the flow of water as well.

Phillip Nichols, Howard County’s assistant chief administrative officer, says that based on those recommendations and a new analysis of Sunday’s storm, the county should be able to implement a mitigation program within a year.

The earliest projects would involve a water retention facility on Hudson Branch and another retention facility.

In addition, the county received a $1 million grant last month from the federal Emergency Management Agency for flood mitigation efforts related to the 2016 storm.

Unfortunately for Ellicott City, the weather forecast for the weekend calls for more rain.