Abstract. The Colombian Ministry of Environment, Housing and Territorial Development issued the Policy for Integrated Water Resources Management in 2010, with the formulation of Basin Management Plans (POMCA) as a key component. The main purpose of these plans is to support land use planning and sustainable management of renewable natural resources. Since the announcement of the policy; however, advances in the formulation of POMCAs have been limited, due to the need of generating knowledge and the necessary information to formulate such plans. To contribute to the generation of such knowledge, we developed HidroCHEP: a Toolbox to support the formulation and hydrologic characterization of Colombian basins. In this paper, we report the design, architecture, implementation and use of the toolbox, to understand the climatic variability of the country and to improve predictions in ungauged basins. The use of the toolbox is illustrated and evaluated through its application in three pilot river basins (Pamplonita, Gualí and Ceibas) each with different level of available hydrologic and climatic data. This paper focuses on the use of the toolbox for the development of one of the products required by the technical guide for the formulation of POMCA, in the Pamplonita river basin. Main advantages and disadvantages of its application are evaluated. It is demonstrated that the toolbox has the potential to support the formulation of POMCAs in the country and to contribute to integrated national water resources management.