GEOGRAPHIA NAPOCENSIS AN X, nr. 2/2016 geographianapocensis.acad-cluj.ro 101 Geographia Napocensis Anul X, nr. 2, 2016 ASSESSMENT OF FLOOD RUNOFF CHANGES UNDER LAND COVER IMPACT USING SCS-CN MODEL AND GIS TECHNIQUES. CASE STUDY: THE BYC RIVER BASIN, MOLDOVA jeLeaPov aNa 1 Abstract: Present study is dedicated to impact assessment of land cover and soil moisture changes on food runoff generation on example of the Byc river basin. SCS-CN model and GIS were used as main methods and techniques for runoff change estimation. Rainfall - main factor for food generation - was taken as for a storm event over the basin of 1% probability. It was found that changes in land cover for last 30 years do not have great impact on food runoff at basin level. However, locally, there can be observed signifcant increase and decrease of food runoff due to modifcation of land use. A great impact on food runoff is caused by antecedent soil moisture conditions. Thus, average decreasing of food runoff due to a dry soil is 40% and average increasing due to wet soil can be up to 60%. Key-Words: food runoff, land cover impact, SCS-CN model, the Byc river basin 1 Institute of Ecology and Geography of Academy of Sciences of Moldova, Laboratory of Landscape Ecology, Moldova, e-mail anajeleapov@gmail.com 1. Introduction Assessment of hydrological systems changes under the infuence of natural and anthropogenic factors is a topic of great actuality and importance (Montanari, A., et all. 2013). The most prominent human activity that leads to modifcation of hydrological system components is land use and spatial arrangement which causes changes not only of natural landscape but also of fow and especially food generation and propagation processes. Understanding of food regime changes under impact of basin management activities as well as under variation of natural factors (especially soil, climate and vegetation) represents a way to fnd better solutions for food mitigation and food risk resilience. In this regard, the aim of present study is evaluation of changes in land use in the last 30 and estimation of their effect on food runoff generation processes on example of the Byc River basin. So far, methodology for estimation of main hydrological characteristics as well as assessment of human impact in ungauged basin has signifcantly progressed and is represented by a series of different method, models and techniques. One of the most popular models used for food runoff calculation is Soil Conservation Service Curve Number model (SCS-CN) (SCS, 1956, 1972) which is widely used for runoff estimation due to its simplicity, few input data, short implementation time and accurate outputs. Utilization of GIS techniques for calculations and spatial representation of results represent a great advantage for user. Thus, for present study SCS-CN model was used to calculate the food runoff and to estimate the perspectives of further model implementation on the rivers of the Republic of Moldova. The results of this research can serve as an argument for further estimation of food characteristics in ungauged basins, optimization of land use practices, development of plans for better land, water resources and food management.