Bosher Dam is a historic but unnatural feature in the James River just west of Richmond, Virginia. A lowhead dam, also called a weir, is what paddlers ruefully call a "drowning machine," this 12-foot-high stone structure interrupts the natural flow of Virginia's largest self-contained river by spanning the waterway between suburban Tuckahoe in Henrico County and the western part of Richmond just west of the Edward E. Willey Bridge.
The structure dates to 1835 at the location of an earlier dam designed to catch fish between slats. The current iteration was part of construction of the James River and Kanawha Canal, a major 19th Century transportation project whose emphasis in 1835 was getting boat traffic around the Falls of the James, the boulder-strewn whitewater that blocked river transport for at least ten miles around Richmond. The dam may have provided power for nearby gristmills and provided sufficient water depth to the Canal flowing on what eventually became a 22-mile pathway as it weaves above the north shore of the James around the Falls.
In recent years, hundreds of lowhead dams have been removed from American rivers in an effort to restore the traditional spawning grounds of native fish with notable nearby dam removals occurring in Charlottesville and in Fredericksburg.
Such fish as shad, herring, and striped bass—which make their migratory spawning runs between March and early June—had been blocked by Bosher, which made migration impossible for at least 300 miles upstream in the James, the Rivanna River, and other tributaries. While the dam still functions to get water into the Canal, which has become more of a historic feature than a means of transportation, it has also created conditions to make this section of the James suitable for powerboating with waterskiing and other activities typically available only on lakes and larger waterways. Perhaps the rise of powerboating explains why, rather than breach or demolish the dam, as has been the recent custom in other communities, the Virginia Department of Game and Inland Fisheries decided instead to build an extensive fish ladder aside the dam. Opened in 1999, the fish ladder allows the migratory fish around the dam via a 17-inch-wide pathway.
With the 10 acres north of the dam belonging to the James River Park System, an opportunity exists to create more public access to this scenic area. Whether such parties as the neighbors along upscale Cherokee Road and Riverside Drive, as well as the Virginia Power Boat Association  will smile on such an effort remains unknown.
One Richmond-area news source has posed the question: "Should a park be created at Bosher’s Dam?"
Incidents at Bosher
Because lowhead dams can be nearly invisible to people on boats, giving an impression similar to the edge of an infinity pool, boaters can encounter them inadvertently. Lowhead dams can be particularly hazardous because they tend to create "hydraulics," currents that push objects (and people) underwater  and then inextricably cycle them for hours, days, or weeks until the water level changes.
- July 17, 1988 - Lisa Everett Cavanaugh, 20 - fatally injured when a boat on which she was a passenger ran over the dam,
- May 26, 1989 - Kari Karte, 22 - uninjured when her boat went over the dam,
- February 20, 1994 - Robert Michael Green, 15 - drowned when he slipped from the dam,
- May 30, 1997 - Janet Heath, 25 - injured when a waterski went over the dam.
- Michael Robinson, Ph.D. P.E., Robert Houghtalen, Ph.D., P.E. "Dangerous dams". Rhode Island Canoe/Kayak Association (Rhode Island). Retrieved 2011-06-26.
- "Nearly 800 dams already removed across U.S.". Society of Environmental Journalists (Jenkintown, PA). 2008-11-26. Retrieved 2011-06-26.
- "Access Week: Should a park be created at Bosher’s Dam?". James River News Hub (Richmond, VA). 2011-01-31. Retrieved 2011-06-26.