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The Drava River plays an important role in the lives of the people who live along its valley. The hydroaccumulation lake of the HPP Dubrava and the drainage channel of the HPP Dubrava are the habitat of many plant and animal species. The chemical properties of water, dissolved oxygen and water temperature influence the life and reproduction of organisms in the water. Therefore, the question arises as to how the chemical properties of the water (oxygen, nitrites, nitrates, pH, phosphates) and the water temperature differ between the drainage channel and the lake of the HPP Dubrava, and whether the water flow through the drainage canal affects the concentration of dissolved oxygen and temperature compared to the lake HPP Dubrava. Over a period of more than six months, water samples are collected weekly from the drainage channel and lake of HPP Dubrava. The chemical properties of the water (nitrates, nitrites, phosphates, pH), dissolved oxygen concentration and water temperature were measured using the GLOBE protocols. The research results indicate that a higher water flow through the drainage canal can lead to more favorable chemical properties of the water, especially lower nitrate concentrations and slightly lower temperatures . It is confirmed that the nitrate concentration and water temperature in the drainage channel are lower compared to the HE Dubrava lake. The drainage channel has higher oscillations and amplitudes of dissolved oxygen in the observed period. Comparing the data provided by Hrvatske vode and GLOBE measurements for pH and phosphates, significant deviations are visible, which are the result of different measuring kits.