Fairfax County is no longer asking whether to keep Lake Accotink. It is studying how small a lake it can afford to keep. The Smaller Lake Accotink Preservation Feasibility Study is weighing a lake of 20 to 40 acres at a depth of 4 to 8 feet. The engineering is about cubic yards of sediment, and much of that sediment comes down Accotink Creek, which runs past Eakin Community Park and Eakin (Mantua) Park before it reaches the dam.
So for Mantua, the lake is the downstream end of the same creek that runs past the neighborhood. The trail along that creek leads there too.
How the County Got From "Dredge It" to "How Much of It"
The current study sits at the end of seven years of plans that kept getting more expensive.
- 2019. The Board of Supervisors approved a full-lake dredge estimated at $30.5 million, followed by maintenance dredging at about $2 million a year.
- February 2023. County staff reported that the sediment to remove had grown to 500,000 cubic feet, up from 350,000, at a rate that would require dredging about every five years. They recommended against dredging and proposed letting the lake fill in as a managed wetland and floodplain forest.
- April 2023. The revised cost estimate put the first dredge at about $95.3 million, plus up to $300 million in maintenance dredging by year 20. That came to roughly $395 million in total.
- May to December 2023. After the wetland recommendation drew strong objections from lake supporters, the Board created a 30-person task force in May, chaired by former Board Chair Sharon Bulova. Its December report concluded that keeping 20 to 40 acres with recurring maintenance dredges was feasible. Its options included a 41-acre lake at an estimated $34 million and a 22-acre lake at $24 million.
- January 2024. At the request of James Walkinshaw, then the Braddock District Supervisor, the Board voted unanimously to direct staff to study the feasibility of a smaller lake, the rate of sedimentation and the condition of the dam.
The difference between the 2019 estimate and the 2023 one comes down to how much sediment there was and how fast more arrives. Those questions are still open, and they are the ones being measured now.
What the 2026 Numbers Actually Say
Two technical products came out of this spring. Neither has received much news coverage since the June open house.
The lakebed survey. The county compared bathymetric surveys from March 2011 and March 2026. Over those 15 years, about 174,120 cubic yards of material settled in the lake, 2,020 cubic yards eroded away, and the net fill came to 172,100 cubic yards. Averaged across the period, that works out to roughly 11,500 cubic yards a year. That figure measures net change in the lakebed. It is not the same as the 23,000 cubic yards a year reported as the estimated accumulation rate in early 2025. The U.S. Geological Survey is still measuring how much sediment enters and leaves the lake. That figure will settle which rate is closer to right.
The dam. Stantec inspected the dam on October 7 and 8, 2025, and issued its report on March 6, 2026. It rated the spillway and stilling basin generally Fair, with localized Poor areas that need near-term repair. The downstream face of the spillway rated Poor, with spalling, scaling and exposed, corroded wire mesh. Sediment covered the upstream face, so inspectors could not examine it. The June presentation said the embankment performs satisfactorily under normal loading but that the spillway needs substantial capacity improvements. The county's FAQ says it does not plan to remove the dam, though it may need to modify it depending on which lake size is chosen.
The Acreage Depends on What You Measure
Lake Accotink's size is easy to misquote because each source measures something different.
| Measure | Acres | Source |
|---|---|---|
| Original lake, per 2023 task force coverage | 110 | FFXnow, December 2023 |
| Lake size cited in that same coverage | 49 | FFXnow, December 2023 |
| Water surface at normal pool | 55 | Dam assessment, March 2026 |
| Existing contiguous open water | 40 | Study boards, June 2026 |
The 40-acre figure is what the June 2026 study uses, and it changes how the options read. A "40-acre lake" means keeping roughly the open water that exists today. The 20- and 30-acre layouts mean shrinking it. In the preliminary 40-acre layout, 38 acres are open water and 2 acres are in-lake wetlands. Reaching a 4-foot target depth would take about 86,000 cubic yards of dredging, with 45,000 cubic yards reused on site and 41,000 hauled away. The boards call these quantities approximate and subject to change.
Against the 2011 to 2026 survey average, an 86,000-cubic-yard dredge equals about seven and a half years of net sediment build-up.
Where Mantua Comes In
According to the Fairfax County Park Authority's stream valley plan, Accotink Creek connects Eakin Community Park, Eakin (Mantua) Park and Accotink Stream Valley Park, flowing downstream from near Pickett Road toward Route 236. The 2023 task force report says 30.5 square miles of the creek's 52-square-mile watershed drain into the lake. It also notes that paved and other impervious surfaces raise storm flows and bank erosion, which sends more sediment downstream. The county's sediment action plan, dated July 2025, names overland stormwater runoff and stream-bank erosion as major sources.
In other words, the sediment the county is surveying passes through Mantua on its way to the lake. Some attendees at the June 6 open house asked how the cost of upstream stormwater controls compares with the cost of dredging. That is the upstream question in budget terms.
The attendance numbers matter here. About 75 people came to the June 6 session, and about 95 percent of those who gave a ZIP code listed 22150, 22151 or 22152, the areas immediately around the lake. Mantua is 22031. The county's summary says most written comments favored keeping a larger lake, specifically 40 acres. That summary is based on five paper comment forms plus verbal feedback. The same summary lists confusion about when a decision will be made as a key finding.
The FAQ answers that question. An initial feasibility study is expected by the end of 2026 or early 2027. An update will follow additional monitoring at the end of 2027, and the Board of Supervisors, not county staff, makes the final decision, possibly after 2027. Updates and an email sign-up are on the county's study page.
Following the Creek This Fall
The Gerry Connolly Cross County Trail, which runs more than 40 miles north to south, lists both Eakin Community Park and Lake Accotink Park among the parks it reaches directly. The Park Authority describes the Accotink Stream Valley section from Pickett Road to Wakefield Park as flat, mostly paved and bridged. It describes the Lake Accotink Park trail from Braddock Road to the marina as fairly level with a stone-dust surface. Inside the park, the brochure map shows 2.2 miles of the Cross County Trail and 1.5 miles of the Lake Accotink Trail. The Park Authority's loop map, dated 2017, gives the full lake loop as 3.9 miles over mixed surfaces. As of the Park Authority's October 3 alerts, no closure or detour was listed on that route.
Dates on the creek and at the lake this month:
- October 9, 6 to 7:30 p.m. All About Owls Campfire at Lake Accotink, covering how to identify barred owls, with marshmallows. The Twilight by Kayak paddle the same evening was showing as sold out.
- October 10. Friends of Accotink Creek cleanups at Hatmark Branch at Vaden Drive from 9 to 11 a.m., the King Arthur Road bridge from noon to 2 p.m., and the Little River Turnpike bridge from 3 to 5 p.m.
- October 16, 5 to 6 p.m. Super Snakes, led by a naturalist with live snakes.
- October 17, 4 to 5:30 p.m. Slithers, Shivers and Shells, featuring live reptiles and amphibians.
Closer to home, the Park Authority's September 2026 operations report lists trail repair and parking-lot paving at Eakin Mantua Park, and parking-lot paving at Eakin Community Park, among its projects from January through July 2026. The basketball court in the Mantua section of Eakin Community Park is being resurfaced and is expected to reopen in early November. The Park Authority says the park's other amenities are unaffected. Before you head to the marina or miniature golf, the park office at 703-569-3464 can confirm the fall hours.
At Sheehan Team, we follow projects like the Lake Accotink study because a park's long-term plans affect daily life in the neighborhoods along its creek. If you would like to talk about how changes nearby affect your own home, we would be glad to help. Work With Us.
