Good data analysis is required for the optimal design of water resources projects. However, data are not regularly collected due to material or technical reasons, which results in incomplete-data problems. Available data and data length are of great importance to solve those problems. Various studies have been conducted on missing data treatment. This study used data from the flow observation stations on Yeşilırmak River in Turkey. In the first part of the study, models were generated and compared in order to complete missing data using ANFIS, multiple regression and Normal Ratio Method. In the second part of the study, the minimum number of data required for ANFIS models was determined using the optimum ANFIS model. Of all methods compared in this study, ANFIS models yielded the most accurate results. A 10-year training set was also found to be sufficient as a data set.

Water is essential for living organisms. The increase in world population, global climate change and rapid growth in industrialization and urbanization have brought with them water issues around the world in recent years. Not only should existing water resources be used reasonably and efficiently but alternative water resources should also be explored and secured. Rainwater harvesting, which is one of the alternative water resources, can provide economic and environmental solutions. For rainwater harvesting, the size of reservoirs in which rainwater captured from roof catchments is stored should be determined. Determining the optimum tank capacity depending on precipitation and consumption rates allows us to make maximum use of rainwater tanks. The aim of this study is to determine the optimum tank capacity for the storage of rainwater captured from roof catchments in order to meet the water demand for agricultural production. Precipitation data were collected from the city of Isparta and its districts. Rainwater tank capacity was determined using the Rippl, residual mass curve, minimum flow and particle swarm optimization methods. Storage capacities varying according to roof areas and consumption rates are shown in a graph. Results show that particle swarm optimization is the best method.