Secchi Day sampling is led by Beaver Water District. Secchi Day is an annual event that takes place on Beaver Lake in August with the goal of collecting important water quality data such as turbidity, chlorophyll-a, total phosphorous, and total nitrogen. On Secchi Day, volunteers take to the water to collect the lake’s maximum depth at which a Secchi disk can be viewed from the surface of the water which tells scientists how cloudy or “turbid” the water is. This valuable data has been collected for years and gives Beaver Water District a good idea of the water quality of Beaver Lake. In October, the District shares out the data results during the Annual Beaver Lake Volunteer Day.
(2025) For the 20th annual Secchi Day, a record high 38 teams covered 35 sample sites in duplicate throughout Beaver Lake. Sampling teams take Secchi disk readings to determine water clarity and collect water samples which are tested for Chlorophyll-a, Total Phosphorus, and Total Nitrogen to determine algal density and nutrient concentration. Secchi depth is inversely related to Chlorophyll-a concentration. Therefore, as Chlorophyll-a decreases, Secchi depth increases. When it comes to producing drinking water, greater Secchi depths and lesser Chlorophyll-a concentrations are best.
Check out the full report on Beaver Water District’s website at Secchi Day Reports | Beaver Water District.
Thank you to the District for this ongoing monitoring of our drinking water supply resource!
