The kind of anchor you use will vary greatly depending on the quality of the lake or river's bottom. A firm clay or silt bottom will work for a fluke anchor, which sinks into the soil to weigh down the curtain. However, these may not be ideal in rocky or "crusted" lake bottoms. Earth anchors are driven several feet into the bottom soil, and can be used in projects with hard and soft bottoms not suitable for other anchors.
You'll want to draw up your anchoring plan before deploying your turbidity curtain. It's important to take into account the direction of the water, as well as its speed and hydraulic load (the amount of pressure that the water will place on your curtain). Sumberged debris will also affect how you want to place your anchors, as these can tear your curtain, or destabilize soil where you're trying to attach your anchor. In places where there's constant water flow, dual-anchoring will keep your curtain parrallel to the current, preventing it from being dislodged. You also will want to consider your placement carefully if using multiple panels; layering curtains may allow you to catch more sediment, or increase the amount of time that particles are allowed to settle.
