Public Works and Environmental Services

CONTACT INFORMATION: Our administrative offices are open 8 a.m. – 4:30 p.m., Mon - Fri
703-324-5500 TTY 711
12000 Government Center Parkway
Suite 449, Fairfax, Va 22035
Shannon Curtis
Chief, Watershed Assessment Branch

Lower Occoquan Watersheds

watershed area mapLocation
The Lower Occoquan watersheds group lies along the southern border of Fairfax County and consists of eight small watersheds which drain either to the Bull Run/Occoquan River system or directly to the Potomac River. These are Old Mill Branch, Wolf Run, Ryans Dam, Sandy Run, Occoquan Creek, Mill Branch, Kane Creek and High Point. The eight watersheds span 45.4 square miles.

Major Streams and Tributaries
Small tributaries within these watersheds include Maple Branch, Stillwell Run, Elk Horn Run, Giles Run, South Branch and Massey Creek.

Unique Features
Approximately half of the Lower Occoquan watersheds area is overlain by the Watershed Protection Overlay District. This zoning district was established in 1982 by Fairfax County in a progressive move to protect the Occoquan Reservoir, a major source of drinking water for the county. This designation restricts development to one residential dwelling unit per five acres, thereby protecting the streams draining to the reservoir from the damaging impacts of more intense land development – primarily nutrient and sediment pollution.

As a result, this portion of the Lower Occoquan watersheds is densely wooded in most areas and contains some of the highest quality streams found in the county. The Laurel Hill property (formerly the Washington, D.C. Department of Corrections/Lorton Prison facility) is almost completely included in the Lower Occoquan watersheds and is comprised mostly of parkland and open space areas. Historic Gunston Hall, the site of George Mason’s Plantation, is located in the southeastern-most portion of the Lower Occoquan watersheds area in the Mason Neck area. This peninsula on the Potomac contains Mason Neck State Park and the Mason Neck National Wildlife Refuge and is bordered on three sides by Belmont Bay, Occoquan Bay, Gunston Cove and the Potomac River.

Improvement Opportunities
The plans identify areas of opportunity for implementing both structural and non-structural improvement projects such as stream restorations, stormwater facility retrofits, community education and stewardship, streamside buffer enhancements and installation of green stormwater infrastructure (GSI). Proposed projects in the plans have recommended priorities. These lists should not be interpreted as specific implementation schedules or a guarantee that the project will be implemented through the planned Capital Improvement Program (CIP). A full list of active or completed Stormwater projects is available online on at Stormwater Improvement Projects or through Jade (Fairfax County's Comprehensive Mapping Application).

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