Protection of environment is particularly important for plains where agriculture and industry are developed, population density is high and land use is intensive. Drainage is generally controlled against frequent floods and high ground water. In addition, irrigation systems are developed for agriculture. Consequently, few water bodies have retained their natural shape and function. Even these are used to receive excessive stream flows and to balance the hydrologic system. Because water resources are vital for any environment, the purpose of their maintenance and protection in the original form is not only landscape conservation but also environmental protection. An example is given of the Mostonga meander relicts.