The accident of Chernobyl enabled the scientific community to study nuclear fall-out effects in situ establishing new kinds of interpretation methods. This study presents the development of ecometric analysis, mainly based on load diagrammes for entire ecosystems and their interpretation with regard to dynamic modeling. Practitioners and scientists in ecology, environmental sciences, limnology, hydrology and geosciences but also in agricultural and life sciences will profit from this textbook. It is the first book on ecometric modeling. Ecometry is an approach to establish so-called load diagrams (effect-dose-sensitivity diagrams) for entire ecosystems like lakes or defined coastal areas. Central aspects concern statistical relationships and causal relationships, clusters and functional groups of interrelated environmental parameters, area- and time compatible data, benefits and drawbacks with the ecometric approach, and the information value of parameters that vary in time and space. The book uses a new and comprehensive set of data on radioactive caesium in lakes (after the Chernobyl accident) to illustrate the various principles and steps in the protocol to establish load diagrammes. The ecometric approach can be used for most pollutants in different types of ecosystems.