Arlington County and the City of Alexandria have a long shared history along the Four Mile Run corridor, particularly the lower 2.3-mile stretch, which runs from Shirlington Road to the stream’s mouth near Ronald Reagan Washington National Airport. During the 1960s and 1970s, that reach was subjected to multiple significant flooding events as the watershed became more urbanized.

Flood Channel
As such, in 1974, Congress authorized the United States Army Corps of Engineers (USACE) to design and construct a flood control channel that would contain the increased flows from the watershed from the 100-year storm event. The 1974 project straightened the Four Mile Run channel, saw the construction of a flood levee, and created a trapezoidal flow channel for the stream. Since the project’s completion over twenty years ago, this reach of Four Mile Run has conveyed the high storm flows safely; no flooding has occurred.

Although the engineered 2.3-mile channel has been successful in the area of flood control, that reach subsequently has lost many of its natural and aesthetically pleasing characteristics. The maintenance requirements for the channel have resulted in the loss of vegetation. In addition, the trapezoidal shape of the channel does not offer the riffles, pools, and shady areas needed to sustain aquatic life.

Potomac Yard Plan
Early in 2000, the Arlington County Planning Commission formed a task force, co-chaired by Carrie Johnson and Neal Sigmon, to recommend plans for the Arlington portion of Potomac Yards, an area which straddles Four Mile Run between U.S. Route 1 and the George Washington Parkway. At the same time, the City of Alexandria had developed its own Potomac Yard Plan for addressing the future of three unused railroad bridges that cross Four Mile Run. The overlap in those ongoing efforts, coupled with the two jurisdictions’ desire to improve stream water quality and recreational potential, created an obvious opportunity for collaboration between Arlington County and the City of Alexandria. Judy Noritake, chair of the Alexandria Park and Recreation Commission, became an active participant in the Arlington work group.

The last component to join the work group was Don Waye, then the staff member at NVRC in charge of monitoring Four Mile Run. Waye indicated that a significant quantity of data related to Four Mile Run had been developed since the 1970's flood control project. He suggested that a formal study may show that changes to the Four Mile Run channel, which could improve the stream’s water quality and recreational potential, are possible without reducing the level of flood protection that has existed for the last 30 years.

Four Mile Run Master Plan
Encouraged by the possibility of improving stream habitat and recreational potential, the work group began to search for funding that would be used toward developing plans for the 2.3-mile stretch of Four Mile Run. U.S. Congressman James P. Moran championed a $1 million federal allocation through the U.S. Environmental Protection Agency for a joint Arlington and Alexandria study. That money was utilized to develop the Four Mile Run Master Plan, which outlines a 30-year vision of enhancements to the 2.3-mile stream corridor.

The first efforts to implement the master plan focus on a demonstration project that includes both environmental improvements and urban components between Mt. Vernon Avenue and US Route 1. A Federal State and Tribal Grant (STAG) matched with local monies will provide funding for the environmental components. Additionally, the work group recently applied for a Transportation Enhancement Grant. If the grant is awarded, the group will use the funds to develop a signature pedestrian-cyclist bridge linking Commonwealth Avenue in Alexandria to South Eads Street in Arlington.