Small water body monitoring in real-time is of crucial importance for the food and pharmaceutical industry. Their observation gives a view of biodiversity behaviour during various changes inside a small water body caused by external factors. The biodiversity of flora and fauna is essential for photosynthesis and other critical natural processes. Because of that, there is a need for products that monitor specific water parameters of a water body, which give a view of their current condition. That being said, product development of the device for water monitoring of small water bodies, which indicates the level of biodiversity, will be discussed. Firstly, small water bodies and water parameters which indicate the level of biodiversity will be defined. Next comes the problem description of the current methods and techniques used for water monitoring. Based on research, the most important functional and operating needs will be defined and used as a basis for the conceptualization phase. Furthermore, the functional structure of the product is made where functions needed for device operation are observed over energy and matter flowing through the device. A morphological matrix is made from a functional structure with the essential functions and technical solution which performs that specific function. Concepts of the device are made with the help of a morphological matrix and are explained and compared with each other. The best concept is picked and used for the detailed design phase, where it is further worked out for performing functions needed for its operation. In this phase, specific design parts will be calculated, as well as standard components needed for its operation. Design solutions will be explained in detail with the help of generated model. Finally, technical documentation will be created.