**2. Methodology**

The PRISMA method [31] was applied in the usual way with a multitude of pertinent keywords and exclusion of (sea, ocean, and lake) where appropriate. The goal of this review is to present a cogent well-sourced picture of the state of monitoring of rivers and streams condition using biological indices with a particular focus on algae. To this end, methods, frameworks, and diverse indices were descriptively enumerated and the general role of algae was expanded upon.
