High Sierra Topix

Water clarity is affected by number of suspended sediments and amount of algal biomass. Most of the high Sierra lakes are clear (oligotrophic) water lakes, in which we know there is very little sediment runoff and low nutrients. Water clarity is an excellent indicator for increased algal growth. Both sediment inflow, as well as algal growth can be assessed by looking at changes in the water clarity. Greening of lakes typically implied increasing algal growth due to increased nutrient loading. Phosphates arrive in lakes through sediment runoff (from roads and trails), feces of wildlife, and the use of soaps, etc. Thus, greening lakes should be an alert for changing lake conditions and nutrient loads. It is much easier to control the amount of nutrients entering a lake at the onset of eutrophication compared to a lake that has been eutrophic for a while. Once there are excessive levels of nutrients in lakes it is difficult to revert back to an oligotrophic state.