Forum geografic. Studii şi cercetări de geografie şi protecţia mediului Volume 10, Issue 1 / June 2011, pp. 157 – 166 (www.forumgeografic.ro) DOI: 10.5775/fg.2067-4635.2011.034.i Structural and Non-Structural Measures for Flood Risk Mitigation in the Bâsca River Catchment (Romania) Gabriel MINEA1, Liliana ZAHARIA2 1 University of Bucharest, Faculty of Geography, Doctoral school: “Simion Mehedinţi - Nature and Sustainable Development”, [email protected] 2 University of Bucharest, Faculty of Geography, [email protected] Received on <December 6, 2010>, revised on <February 21, 2011>, accepted on <March 29, 2011> Abstract Rezumat. Măsuri structurale şi nestructurale de diminuare a riscului inundaţiilor în bazinul The most common natural hazards affecting the Bâsca hidrografic al râului Bâsca (România) River Catchment (extended over a surface of 785. 1 sq. km in the Curvature Carpathians) are floods and flooding. Cele mai frecvente hazarduri naturale care afectează The purpose of this paper is to investigate and analyze bazinul hidrografic al râului Bâsca (extins pe suprafaţă de structural and non-structural measures for flood risk 785,1 km2 în Carpaţii de Curbură) sunt viiturile şi mitigating in this catchment. inundaţiile. Prezenta lucrare are drept scop investigarea şi The study focuses on the main factors which generate analiza măsurilor structurale şi nestructurale cu rol de and favour floods, as well as on flood characteristics diminuare a riscului indus de inundaţii în bazinul (frequency, the largest floods and its consequences). menţionat. The main methods are the statistical analyze Studiul se concentrează pe principalii factori care hydrologic and climatic data, field observations, generează şi favorizează viiturile şi caracteristicile expeditionary mapping and spatial analyses using acestora (frecvenţa, cele mai mari viituri şi consecinţe). Geographic Information Systems (GIS). Principala metodă este reprezentată de analiza In order to analyse flood potential, there were statistică a datelor hidrologice şi climatice, observaţia de processes processed maximum instantaneous monthly and teren, cartarea expediţionară şi analiza spaţială utilizând annual discharges of the Bâsca River at the Bâsca Roziliei Sisteme Informatice Geografice (SIG). hydrometric station (1953 - 2007), Varlaam I (1956- În analiza potenţialului de producere a viiturilor au 2005), Comandău h.s. (1968-2005) and of the Bâsca Mică fost prelucrate debitele maxime instantanee, lunare şi River at the Brebu h.s. (1959-1974) and Varlaam II h.s. anuale ale râului Bâsca de la staţiile hidrometrice Bâsca (1973-2005). Roziliei (1953 - 2007), Varlaam I (1956-2005), Considerations on structural and non-structural Comandău (1968-2005) şi de pe râul Bâsca Mică de la measures for protection against floods are presented in the Brebu (1959-1974) şi Varlaam II (1973-2005). last part of the paper. An inventory of structural works in În ultima parte a lucrării sunt prezentate consideraţii the middle and lower part of the catchment asupra masurilor structurale şi nestructurale de protecţie (hydrotechnical and erosion control works) and their împotriva inundaţiilor. Este realizat un inventar al condition was made. lucrărilor structurale din sectorul mijlociu şi inferior al bazinului (lucrări hidrotehnice şi antierozionale) şi este Keywords: floods, structural and non-structural analizată starea acestora. measures, the Bâsca River Catchment Cuvinte cheie: viituri, măsuri structurale şi nestructurale, bazinul hidrografic al râului Bâsca frequency and amplitude of flooding, in the context INTRODUCTION of climate changes, and on the other hand to an Floods are natural hazards with complex increased vulnerability determined by the expansion consequences, both direct and indirect: of socio-economic activities in floodplains (Şerban geomorphological, economic, social and ecological. and Gălie, 2006), measures and actions to limit and They hold about one third (34%) of the total reduce floods negative impacts on society and the number of natural disasters produced worldwide in environment need to be effective. At the Union the 1900-2007 period (Magdelaine, 2010). European level, the management of the floods risk Knowing that in the future flood risk is estimated is expected to be completed within a common to raise, due, on the one hand, to increasing framework for action set by the 2007/60/EC Copyright © 2011 Forum geografic. S.C.G.P.M 157 Structural and Non-Structural Measures for Flood Risk Mitigation in the Bâsca River Catchment (Romania) Directive ―On the assessment and management of Vineţişu (206 inhabitants1). The majority of the flood risks‖ which requires Member States an inhabitants is concentrated in the lower part of the integrated flooding risk management with emphasis Bâsca River Catchment, especially along the on actions of prevention, protection and valleys. In the upper part of the catchment, the preparedness. These involve complex and diverse population is concentrated in Comandău Depression measures, both structural and non-structural, their (Comandău Commune). judicious combination and adequate to local The humanization of the valleys and the conditions being necessary. presence of urban and road infrastructure increase The purpose of the paper is to highlight the flood flooding vulnerability of these areas. potential and also to investigate and analyze the structural and non-structural measures for reducing the flood risk in the Bâsca River Catchment. The results of the present study complete and update specific information in the uncertain parameters of maximum discharge and floods from the Bâsca River Catchment, published in papers and hydrologic synthesis carried throughout Romania (Râurile României. Monografie hidrologică, 1971; Ujvári, 1972) and at regional scale (Monografia hidrologică a bazinului hidrografic al râului Siret, 1967; Diaconu, 2005; Zaharia, 2004, 2005; Chendeş, 2007 etc.). Information concerning terminology and case studies regarding hydric risks were found in papers by: Şelărescu and Podani (1993), Kundzewicz (2002), Sorocovschi (2003, 2004), Armaş (2008), etc. An inventory of the damages caused by these phenomena has been published by Zăvoianu and Podani (1977) at regional scale and FRMI (1994) and Aquaproiect (2006) for the Bâsca River Catchment. A model of economic management of negative effects caused by floods in a catchment is developed by the Tennessee Valley Authority even since in 1933 (www.tva.com). Fig. 1 Location of the study area (Hydrometric stations: I. Comandău; II. Varlaam I; III. Brebu; IV. Varlaam II STUDY AREA and V. Bâsca Roziliei) Positioned in the external region of the Data source: information processed from topographic maps, scale Curvature Carpathians (subunit of the Eastern 1:25,000 Carpathians), the Bâsca River Catchment (Fig. 1) DATA AND METHODS has a surface of 785,1 sq km. It lies at a medium altitude of 1081 m between Lăcăuţi Peak (1777 m The present analysis in based on the following a.s.l.) and the confluence with the Buzău River (385 types of data: m a.s.l.). The Bâsca River (length = 81 km), is one - cartographic data (topographic maps scale the main tributaries of the Buzău River. 1:25,000 by Military Topographic From a demographic point of view, the Bâsca Department -MTD-, 1982); River Catchment is situated in an area with low - climatic data: precipitations (maximum density (8.35 inhabitants/km2). In this catchment, amounts fallen in 24, 48 and 72 hours and there are two communes: Comandău (1,042 monthly averages) at the Lăcăuţi (1961-2000) inhabitants) and Gura Teghii (3,884 inhabitants) and Penteleu (1988-2007) weather stations and two villages appertaining to the town of (w.s.), situated at 1776 m a.s.l. and Nehoiu: Bâsca Roziliei (1,428 inhabitants) and 1The inhabitants number are according to The National Institute of Statistic, Romanian census data, 2002. 158 Copyright © 2011 Forum geografic. S.C.G.P.M DOI: 10.5775/fg.2067-4635.2011.034.i Forum geografic. Studii şi cercetări de geografie şi protecţia mediului Volume 10, Issue 1/ June 2011, pp. 157 - 166 respectively 1632 m a.s.l; these data were energy relief and drainage density), vegetation, soils provided by the Regional Meteorological and antecedent conditions of the catchment (e.g. Center Muntenia, Buzău and Clima land use) (Minea and Zaharia, 2010). României, 2008; - hydrological data: maximum instantaneous Precipitations monthly and annual discharges of the Bâsca Precipitations represent the main factor River at the Bâsca Roziliei hydrometric generating floods in the Bâsca River Catchment. station (h.s.) (1953 - 2007), Varlaam I h.s. Although in the catchment region, the mean (1956-2005), Comandău h.s. (1968-2005) and annual amount of precipitation are relatively low of the Bâsca Mică River at the Brebu h.s. (827.3 mm at Lăcăuţi w.s. and 664.3 mm at (1959-1974) and Varlaam II h.s. (1973-2005) Penteleu w.s.), rainfalls can trigger floods especially (Table 1); discharges during the main floods; during summer, when the rains have a torrential the hydrological data were provided by the character. In the morphological features of the ―Romanian Waters‖ National Administration, catchment, these rains can generate flash-floods. Buzău – Ialomiţa Water Basin Administration At annual time scale, the highest average amount (BI BWA), and the National Institute of of annual precipitation was recorded in June at Hydrology and Water Management Lăcăuţi w.s. (130.2 mm in the period 1961-2000) (NIHWM); (Fig. 2) and in July at the Penteleu w.s. (117.4 mm, - qualitative data: physical status of in the period 1988-2007). hydrotechnical works (from the Forest Research and Management Institute - FRMI) 250 and 24h 48h - quantitative data: number of hydrotechnical 200 72h works (by the Aquaproiect and FRMI). monthly average 150 Table 1 Data about the hydrometric stations from 100 the Bâsca River Catchment Stream (mm) Precipitation Hydrometric A* H ** Analysed 50 River B length station (km2) (m) period (km) 0 1959- J F M A M J J A S O N D Brebu*** 185 1240 36 Time Bâsca 1974 Mică 1973- Fig. 2 Maximum precipitations (rain and snow) in Varlaam II 235 1171 43,7 2005 short periods reached at Lăcăuţi w.s.