Monitoring of hydrochemical parameters of lignite mining lakes in Central Germany using airborne hyperspectral casi-scanner data

Active and abandoned coal mines have a huge impact on the environment. The most challenging problem is caused by acid mine drainage (AMD). Using traditional methods such as single point measurements to determine and analyze mining lakes over the period of a few years is difficult due to the lakes' high dynamic and inner differentiation. To overcome this difficulty, a new method has been successfully tested to additionally monitor residual lakes. Using a manifold data set (like images from the hyperspectral airborne scanner casi, ground truth data, spectral field and laboratory measurements), the optical properties (reflection, absorption and scattering) of acid mining lakes were defined for the first time ever. Furthermore, hydrochemical parameters in quality and quantity were ascertained in a two-stage process. First, optical properties of the mining lakes were analyzed and defined for each of the limnological stages of development. Second, based on the lakes' optical properties, algorithms for classification of the hydrochemical parameters evolved and were reliably utilized. The new algorithms enable the monitoring of mining lakes from acidic to alkaline as well as the quantification of the hydrochemical properties inside the lake water.

Research Highlights► The paper show new system of monitoring of acid mining lakes. ► First time the optical properties of acid lakes were described and analysed. ► Using hyperspectral casi data we can detect the development of the lake stages. ► The algorithm enables the quantifying of hydrochemical properties and ph values.