of the stream where the stream is flowing freely, vortex flow prevails and the stream is flowing fastest where the radius of the bend is smallest, and slowest where the radius is greatest. The shallows around the point bar can become treacherous when the stream is rising. As the water depth increases over the shallows of the point bar, the vortex flow can extend closer toward the convex bank and the water speed at any point can increase dramatically in response to only a small increase in water depth. Fallacy regarding formation of point bars An old fallacy exists regarding the formation of point bars and oxbow lakes which suggests they are formed by the deposition (dropping) of a watercourse's suspended load claiming the velocity and energy of the stream decreases toward the inside of a bend. This fallacy relies on the erroneous notion that the momentum of the water is "always" slowest on the inside of the bend (where the radius is smallest) and fastest on the outside of the bend (where the radius is greatest), which ignores its increased angular momentum. Mass deposition of suspended solids rarely occurs on one bank save in tidal estuaries; instead, vortex flow being faster on the inner bank compensates for the greater height and therefore mass of water flowing downstream along the concave bank, and the rough, shallow bed usually provides per liter of water above more agitation to maintain any suspended particles. Any relatively steady gradient open flow not met with complex interactions with contrary flows, such as tides, or major obstacles, flows around a bend in a simple model of vortex flow, with relatively few variables and coefficients. Point bars typically have a gently sloping floor with shallow water. Clearly a higher proportion of the water in very shallow water does much more work to overcome friction above and below (especially in a countervailing breeze) which lowers its speed, see Bernoulli's principle. It is probably this close-quarters observation which led early geographers to believe in deposition by sedimentation of suspended matter rather than close-to-bed secondary currents. In a steady-gradient section of a watercourse, sedimentation may occur where the water is saturated and the shallow bank has high flow resistance but does not agitate the suspension. Similarly, the fallacy has scant explanation as to why deposition occurs at a stream bend, and little or none occurs where the stream is following