Manual for Operation of Mini Secchi Disc and the Mobile App TurbAqua Developed as Part of Revival Project

Abstract

The Secchi disc measures transparency of water bodies in a fast, easy and precise way. The Secchi disc is a white disc that is lowered into the water and the depth at which this disc disappears from sight is logged as Secchi depth in the App. Transparency is the depth at which disc reappears, i.e., or how deep the sunlight can penetrate into a lake. The mini Secchi disc is basically a manually-operated tape measure with a white Secchi 10 cm disk and a brass weight of 100g attached to the tape end. The weight is manufactured using a metal lathe and the disc is made of white polypropylene sheet. The measuring tape is approximately 8m long wrapped around a 3D printed bobbin. For the easy handling of the device a polypropylene finger strap and nylon lanyard are attached to the casing. For prediction of colour of the water body, a vinyl-laminated Forel Ule colour scale sticker (with colour ranging from Indigo blue to Cola brown) is placed on the outside of the casing and the entire device is held together using stainless steel or brass fixings. In addition to this, an i-Button housed in a Thermochron water proof capsule ((DS9107) is attached to one of the weights, designed for measuring the water temperature