Spatial variation of stream power in the Buz u and Ialomi a River Catchments (Romania). Stream power is a parameter that quantifies river energy, respectively its work ability. The aim of this paper is to estimate the stream power of rivers from the Buz u and Ialomi a catchments and to present the difficulties in calculating and interpreting its variation. Cross-sections accomplished by the National Administration "Romanian Waters" were used in fulfilling this objective, at hydrometric stations on the Ialomi a, Prahova, Buz u, Basca Chiojdului and Basca Rivers. Based on these profiles, and using hydraulic methods, parameters like flow velocity, discharge and stream power were calculated. Analysis results indicate that the rivers draining the Carpathian and Subcarpathian regions are dynamic. They have a specific stream power of more than 150 W/m2 and are susceptible to rapid evolution. In the Romanian Plain rivers are less energetic (a specific stream power below 40 W/m2, excluding river sectors with braided trends and incised channels). Also they are characterized by a less intensive dynamic.