More than 71% of the earth's surface is made up of water with an average depth of 3,800 m. More than 99% of Earth's liquid water is made up of oceans. The rest is water found in freshwater lakes and rivers, which hides their fundamental importance in the maintenance and survival of terrestrial life (Wetzel, 2001). Small water reservoirs are constructed for flood protection, water supply and irrigation (Baxer, 1977). Potentially, these small water reservoirs can play the environmental role of natural lakes, pools or ponds. Shallow lakes and ponds are collectively very rich in terms of biodiversity (Fahd et al., 2009). Small reservoirs are larger and more temporally stable than basins and ponds (Illyova and Pastuchova, 2012). On average, local species richness in lentic systems tends to increase from small, temporary water bodies to larger, more permanent systems (Davies et al., 2008). According to Johnson and Allen (2012), plankton are made up of small organisms and float in water, neither able to swim effectively against most currents nor attached to the bottom. Zooplankton are small aquatic invertebrates that feed on phytoplankton. Although “plankton” float or drift passively, some zooplankton can be good swimmers (FAO, 2005). In freshwater ecosystems, zooplankton play a key role as a food source for other invertebrates and fish and as an effective filter of phytoplankton (Lampert, 2006; Chen et al., 2009; Preuss et al ., 2009; ). It consists of copepods, protozoa, rotifers, cladocerans and others which can also serve as indicators of water quality (Davies and Otene, 2009). Zooplankton lies in the middle position between autotrophs and other heterotrophs, maintaining an important medium for lake productivity which is the trophic condition of the lake (Wetzel, 2001). The decrease in zooplankton in the outflows of eutrophic lakes is slower than in the outflows of mesotrophic lakes (Czerniawski and Domagala, 2010). According to Sumardi et al. (2012), the distribution of chlorophyll-a must be understood in order to provide a good method for explaining environmental conditions. Phytoplankton productivity or total biomass is necessary to determine the trophic state of a lake (Carlson, 1977). Padisák et al. (2004) found that chlorophyll-a was used to estimate algal biomass in the aquatic ecosystem because it is common in most algae. Thus, it is not clear whether nutrient-rich lakes with certain morphological characteristics can achieve chlorophyll levels - a level typical of nutrient-poor lakes, even if nutrient levels decline (Seip, 1992).