Hjulstrom Curve Notes

The Hjulstrom curve is a graph used by hydrologists to determine if a river will erode, transport, or deposit sediment based on particle size and water velocity. It shows the relationship between stream velocity and its ability to transport materials of varying sizes, from clay and silt to boulders. There are lines for critical erosion velocity and settling velocity - particles are eroded above the critical line and deposited below it. The curve indicates that particles around 1mm require the least energy to erode as they are easily moved sands, while larger particles like pebbles and boulders need higher velocities to erode.