To the naked eye, Watts Branch is a quiet stream that meanders from Rockville, through Potomac and eventually joins the Potomac River and the Chesapeake Bay. But to environmentalists and local officials, it’s much more. It enters the Potomac River at the WSSC water filtration plant on River Road., making it the major source of drinking water for Montgomery and Prince Georges Counties. Millions of residents drink from the Watts Branch.
In late May, more than two dozen members of green groups, the County Executive, the Mayor of Rockville, the Department of Environmental Protection Director and staff, and the director and staff from the Montgomery Parks Department boarded a bus to tour Watts Branch and explore the challenges of protecting our drinking water from sediment pollution carried by stormwater runoff. The tour was sponsored by the Watts Branch Watershed Alliance, Conservation Montgomery, and the Montgomery County Group of the Sierra Club. About 38 people attended, including County Executive Marc Elrich, Rockville Mayor Bridget Newton. Department of Environmental Protection (DEP) Director Adam Ortiz, Parks Director Mike Riley, and members of their staffs. Also in attendance was the Deputy Chief of Staff for Councilmember Tom Hucker; Chair of the Council Transportation and Environment Committee. Leaders from many environmental and other organizations were aboard the bus as part of a recently formed Green Environmental Network.
“Every drop of runoff from Watts Branch goes to the Potomac,” said Sylvia Tognetti of the Sierra Club Group of Montgomery County, who was part of the committee that organized the tour. “And everything we do in our Up County watersheds adds to our water treatment costs.”
Tour guide Ken Bawer, from the Watts Branch Watershed Alliance and the West Montgomery County Citizens Association, led the group to examples of various types of stormwater management facilities and problem areas. Watts Branch flows across jurisdictions and through various public, private, commercial and residential properties, under roads, through school sites and parks demonstrating the need to use all available tools to address runoff as well as to engage all sectors.
“Every stormwater source, including lawns, parking lots, and roads, provides opportunities for partnership to implement collaborative solutions,” said Diane Cameron, who worked with Bawer to map out a list of 29 sites that started at the vacant Rockville Village Center and ended at Glen Road in Potomac.
The Washington Suburban Sanitation Commission (WSSC) had a proposal, now on hold, to spend approximately $83 million to move their River Road intake pipe to the middle of the Potomac River (known as the proposed mid-river intake). The new intake had been recommended in a 2002 Source Water Assessment (SWA) to avoid runoff and high variability of water quality from the Watts Branch during storm events that present challenges for treatment, requiring increased use of chemicals to provide safe drinking water.
However, the runoff is not on hold, and the mid-river intake would not have addressed the increases in sediment loads from Seneca Creek watershed which enters the Potomac a few miles upstream. The SWA had recommended source water protection in addition to the new intake. It is of note that, years earlier, an important justification for establishing the Agricultural Reserve and maintaining rural low-density zoning in the Up County was to protect the public water supply.
“I hear more concern about Watts Branch than any other watershed these days, besides Sligo Creek,” said Elrich. “Looking at the map of Watts Branch, I see tentacles that lead to developed parts of the county where the problems are found.”
Sediment loads from all Up County watersheds as well as from the Monocacy River in Frederick require the addition of treatment chemicals at the Water Filtration Plant resulting in discharges much greater than the loads entering the facility, and in excess of the plant’s discharge permit under the Clean Water Act. A consent decree reached because of a lawsuit originally brought by the Potomac Riverkeepers, joined by the Chesapeake Bay Foundation and the Maryland Department of the Environment requires WSSC to upgrade the capacity of the plant to handle solids, at an estimated cost of $157 million.
The group viewed a small portion of the Watts Branch watershed to observe the extent of the management challenge. The sites visited were generic examples of stormwater runoff problems since it is impossible to cover the entire watershed in just a few hours. Bawer pointed out sources of uncontrolled runoff between jurisdictions (City of Rockville and Montgomery County) and from various sites such as Public Schools, County Parks, private clubs, public roads, townhouse developments, and single-family lots. Many of the examples illustrated the need to break down departmental silos in order to more effectively address runoff problems.
For example, upstream of where the Watts Branch stream intersects with Ambleside Drive, erosion and lateral movement of the stream has exposed two sewer manholes. To stabilize these two short stretches of the stream and install liners in the pipes to prevent sewage leaks, , WSSC has built over half a mile of access road at an approximate cost of $750 million, and installed a temporary bridge. In between the exposed manholes there is approximately 2,000’ of eroded stream channel, which also expose Pepco power poles to the stream channel. Addressing these areas in between would reduce ongoing erosion and avoid significant future costs to repair aging infrastructure as well as reduce sediment at the drinking water intake, all of which is paid for on our water bills if not through the Water Quality Protection Charge. But WSSC only has a mandate to address exposed pipes to prevent or repair Sanitary Sewer Overflows (SSOs), which is required under a consent decree.
To stabilize Watts Branch, it will also be necessary to capture and treat stormwater runoff from the source, i.e., upstream roads and land areas that are the primary cause of stream erosion and sediment loads at the water intake. This will require the Montgomery County Departments of Environmental Protection, Parks, Transportation, as well as WSSC, the State Highway Administration and property owners to work together. An example of the results of this kind of collaboration is in the Breewood Tributary to Sligo Creek restoration project in Wheaton, which the County highlighted as part of the Chesapeake Bay Awareness Week celebrations.