1. Definition of Lakes and Their Position in the Romanian Territory

Limnology is one of the most important disciplines of hydrology. It studies inland waters and all other standing waters (natural or artificial), including hydrologic phenomena, physical or chemical, in relation to the environment (chemism, thermals, dynamics, development capabilities of the flora and fauna associations, etc.), as well as the way they are valorized by man. From a historical point of view, limnology is only approximately one century old and the founder of limnology is considered to be François A. Forel from the University of Lausanne (Switzerland). It is very important to make a clear distinction between similar terms, such as “lake” and “pool” and define a clear terminology. Out of the grand total of 1 million lakes, distributed all around the world, in Romania, there are currently about 3,450 lakes. There are many types of lakes and numerous classifications are based on several factors, such as: the origin of the lacustrine basin, hydric regime, thermal regime, mineralization degree, trophic potential, geographic position, nature (natural vs. anthropic). The anthropic category is devised into smaller types, depending on the size (the amount of the water reservoir), or on the purpose (hydro-energetic, drinking or industrial water supply, irrigations, pisciculture, recreation, balneotherapeutic, residue cleaning, wet concentration, etc.). The Red Lake is a natural dam lake, which was formed after a huge landslide blocked the Bicaz Valley in 1837. Here, the objective is emblematic, because it is the most well-known natural barrage lake in Romania.