The aim of this research proposal is to determine the biodiversity of the macrozoobenthos population. Macrozoobenthos known as an indicator of the quality of the aquatic environment that supports other living creatures in the reclaimed area. The bioindicators can be organisms or biological responses which presence is a marker of environmental conditions. Benthos is one of the bio indicators that live in the bottom or sediment of the waters. Benthos has different responses to pollutants entering the river waters and is immobile. Gaskell Sand Quarry is the right area for the study proposal object because it has a main river so that it can be used as sampling object of benthos population to understand the pattern of distribution and it's environmental factors that support the lives of this creature.