Water Clarity

Water clarity is forecast by CBEFS using the amount of sediment and algae in the water column. The amount of material in the water is used to estimate the depth below the water surface at which a black and white disk can still be seen. This distance is also termed "Secchi depth" and is a measure of the water clarity. Very clear waters with high water clarity have a very deep Secchi depth. That is, the disk can still be seen quite deep in the water. As more material is suspended in the water, the disk can no longer be seen as deep in the water and the Secchi depth gets shallower (closer to the water surface). Algae blooms, waves mixing up the sediment, and sediment discharged from rivers are examples of processes that can shallow the Secchi depth and reduce water clarity. For those interested, Secchi depth is forecast in CBEFS using equations from a scientific paper by Turner et al. published in 2021.