Better Water Management of Critical Habitat for Endangered Species Hydrology Corner Blog In the United States, the Endangered Species Act of 1973 (ESA) defines endangered species as “any species which is in danger of extinction throughout all or a significant portion of its range… “ and critical habitat as “the specific areas within the geographical area occupied by the species … on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection.” Read more...http://aquaticinformatics.com/blog/water-quality/better-water-management-critical-habitat-endangered-species/