When it rains, not only does storm water flow downstream, but so do the banks of small streams emptying into Red Hill Branch, bringing other pollutants with the eroding soil. In a move to stem environmental problems and add wildlife habitat, Howard County has begun four restoration projects for the waterway in Ellicott City.
Officials say they expect the work, which includes overhauling a storm-water pond and stabilizing more than 5,000 feet of the banks of three streams, to be completed by May.
Project manager Mark Richmond said the pond behind Salterforth Place will go from being a depression that is dry most of the time to a larger pond that always has water.
"We are trying to create a small ecosystem," he said.
The pond now covers about half an acre. It was redesigned to cover about three-fourths of an acre, he said. Parts will be deeper, and vegetation near the pond will help prevent erosion. Plans call for a variety of plants that thrive in wet soils, including colorful blue flag iris, cardinal flower, buttonbush and lizard's tail. About 50 shrubs and trees — river birch, American sycamore and red maple among them — will be added to the pond slopes and surrounding areas.
"We are trying to create varying levels for water quality and habitat," Richmond said.
Nearby, sections of streams by Threshfield Court, where banks have washed away so severely that trees have toppled, will get a makeover, as will ones near Bramhope Lane and Meadowbrook Park. In addition to regrading, the work will include placing stone and fiber mats to control erosion, as well as planting trees and shrubs.
"The roots hold the banks and provide habitat for wildlife," Richmond said.
"Based on preliminary monitoring data, we're seeing hundreds of pounds of the primary pollutants … per year coming into the pond," he said. The stream by Bramhope Lane sends more than 400 pounds of sediment downstream during an average storm, and it's the smallest of the three streams being worked on.
Richmond said the revamped pond alone should increase the removal of sediment, nitrogen and phosphorus from the current rate of 5 percent to 10 percent to between 40 percent and 60 percent.
The work is part of larger, related efforts, as well as years of environmental restoration across the county.
"We've got an ongoing plan to retrofit streams. We both actively go out looking for streams to repair and listen to citizen complaints," Richmond said.
As one of the six Chesapeake Bay states, Maryland must comply with the "pollution diet" that the Environmental Protection Agency adopted in December 2010. The federal regulations require that the states take action by 2025 to reach reductions of between 15 percent and 25 percent in nitrogen, phosphorus and sediment polluting the bay. Much of that work falls on local and state governments, which must shoulder the expense as they try to rebound from economic difficulties.
As a result of the mandate, Richmond said, the county has begun to ratchet up efforts to do more work sooner.
In addition, Howard County is putting together an outreach campaign to encourage property owners to use rain barrels and rain gardens to control storm runoff and to landscape their yards. The pilot campaign may be in neighborhoods along Red Hill, but it will eventually go countywide.
"If enough people do it, it will minimize the number of large projects we will have to do," Richmond said.
These four projects are estimated to cost about $3.25 million, with about $960,000 of that funded through state grants.
In a broader context, these are all efforts to remove pollutants from waters leading to the bay, said Jay Sakai, director of the Water Management Administration at the Maryland Department of the Environment.
Rain gardens and street sweeping can be part of the mix, he said.
"Stream restoration is one piece of the puzzle," he said.