SECCHI DISK GRAPH SIMULATOR

Lake Association member Peter Barber holding a Secchi disk and viewscope. Secchi disk monitors report their findings to Lake Stewards of Maine, which maintains statewide Secchi disk readings and provides resources should reduced transparency indicate water quality deterioration. Fortunately Pleasant Lake has ranked high over time-we often report transparency at depths over nine meters. This simple measurement, which varies monthly and yearly, is highly correlated with water quality and thus the health of the lake. Measuring Secchi depth every two weeks during late spring, summer, and early fall flags reduced transparency and signals potential problems. Of concern are factors such as sediment, erosion runoff, and algae growth. Some, such as solar glare or angle of sunlight, have no bearing on water quality. Multiple factors affect water transparency. Readings are done at the PL/PPA buoy, anchored at Pleasant Lake’s greatest depth of 62 feet.

SECCHI DISK GRAPH SIMULATOR

If you’d like to see what it’s like, Lake Stewards of Maine provides a Secchi simulator on its website. Noting exactly the depth at which the disc disappears is inherently imprecise, but practice helps a monitor approach consistency from reading to reading. The monitor slowly lowers the disc until it disappears entirely from sight, and notes the depth at which it disappeared. The scope-think of a glass-bottomed boat-allows monitoring without interference from refracted light and solar glare. The Secchi disk, attached to a tape measure, is lowered over the side of a boat and observed through a hand-held viewscope lowered just below the water surface. This depth of disappearance, called the Secchi depth, is a measure of the transparency of the water. It is lowered into the water of a lake until it can no longer be seen by the observer. The North American Lake Management Society explainsĪ Secchi disk is an 8-inch (20 cm) disk with alternating black and white quadrants. We report the data we collect to Secchi Disk Readings Data are used for environmental status monitoring and assessment of eutrophication in the Baltic Sea and Gulf of Riga.Lake Association volunteers employ various methods to monitor Pleasant Lake’s water quality including Secchi disk readings, dissolved oxygen (DO) testing, water column temperature logging, and phosphate testing.

Measurements were done onboard research or naval vessels or self-propelled boats during daylight hours. Measurements were performed by personnel from the Baltic Research Institute of Fishery of Latvia (BaltNIIRH) (1973 - 1989), Riga Hydrometeorological Centre of Latvia (1989 - 1995) and Latvian Institute of Aquatic Ecology (since 1995). Additional existing data from monitoring and public projects are incorporated into this dataset. The majority of the dataset consists of measurements from the Marine Monitoring Program since 1973. This dataset contains information on water transparency, as measured by Secchi disk, in the territorial and economic waters of Latvia and Estonia in the Baltic Sea and Gulf of Riga. Territorial and economic waters of Latvia in the Baltic Sea and Gulf of Riga A few stations in territorial and economic waters of Estonia in the Baltic sea and Gulf of Riga Ongoing monitoring measurement of transparency by Secchi disk Effect of climate change on aquatic ecosystems in Latvia(KALME) LIMOD(LIMOD) Implementation of innovative ecotoxicological methods for identification of natural and anthropogenic pollution impact on Latvian territorial waters(HIDROTOX) Innovative approaches for marine biodiversity monitoring and assessment of conservation status of nature values in the Baltic Sea(MARMONI)

Secchi disk graph