THE CHARACTERIZATION OF LIQUID DISCHARGE IN THE HYDROGRAPHIC NETWORK OF THE TINOASA CIUREA WATERSHED, IASI COUNTY

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1 THE CHARACTERIZATION OF LIQUID DISCHARGE IN THE HYDROGRAPHIC NETWORK OF THE TINOASA CIUREA WATERSHED, IASI COUNTY Claudiu PRICOP, Florian STĂTESCU Technical University Gheorghe Asachi of Iaşi, Faculty of Hydrotechnical Engineering,Geodesy and Environmental Engineering Bd. D. Mangeron 65, Iasi , Romania Abstract This paper analyzes the hydrological parameters of liquid flow from the representative hydrographic basin Tinoasa Ciurea, according to the climate changes at global and Romanian level. The results of researches made in the hydrographical basin Tinoasa Ciurea were based on data obtained from a well established number of observation and measurements points, in a long series of years, which helps to determine the hydrological parameters of liquid flow in a certain period of time. Also, in all the stages of the research were taken into account the conditional factors of liquid forming and solid flow in the representative hydrographic basin: mean altitude, mean slope, relief, gelogy, soil, vegetation, etc.. The influence of multiannual monthly mean temperature increase, evaporation and evapotranspiration coefficients increase, rainfall quantitative decrease, all correlated with short period of rainfall in excess excepting February 2010, are determinants factors of liquid and solid flow producing in the Tinoasa- Ciurea hydrographic basin. The research method is applied in small hydrographic basins and is based on the split of representative hydrographic basin in 5 sections, means 5 hydrographic subbasins, where monthly, annual, multiannual monthly mean and total multiannual flows are analyzed. The paper presents the results and evaluations covering a longer period of time, based on data obtained from the observation and measurements of various parameters recorded in the Tinoasa Ciurea hydrographic representative basin, Iasi county, referring the determinations concerning the multi-year discharge in a 19 years period. ( ), multi-year average values of discharge in Tinoasa River in years and multi-year variation of average rainfall for a 30 years period. Keywords: representative basin, multi-year average flow, rainfall, discharge. Submitted: Reviewed: Accepted: INTRODUCTION According to the definition, the representative basins are research units that on a 1:1 scale model series, in natural conditions, in which an intensive program of hydrometeorologic observations and measurements is carried out, providing the possibility to determine the elements required to establish the rules of flow formation in watersheds principles obtained in the experimental stations (Institute of Meteorology and Hydrology, 1980). In the representative basins, there is the possibility to follow up the discharge processes, starting from particular cases to general ones, an opportunity that can lead to clear conclusions regarding the influence that various factors have on the discharge. Through the researches carried out, there is a possibility to find answers for many hydrological issues, using a limited number of observation points and measurements (Institute of Meteorology and Hydrology, 1980). The results obtained during this research are ultimately used to check the existent graphical or mathematical relations related to the discharge, as well as to establish their components (the hydrological parameters) for their subsequent practical application. Given the importance of representative basins in the research of discharge forming processes on small rivers, a series of criteria were taken into consideration for their selection, including: - the diversity of physical-geographical Available on-line at Valahia University Press Further reproduction without permission is prohibited

2 geology, geomorphology, soils and vegetation) and various subbasin general forms - the representative basin must be typical for vast territories in the country - the existence inside the representative basin of subbasins, allowing the investigation of factors which generate the discharge on experimental areas and very small areas basins. - the homogeneity of the subbasin conditions so as not to make many corrections to the discharge parameters - the degree of river use in the representative basin should be as low as possible, so that it does not significantly impact the hydrological regime - the existence of a meteo station inside or near the representative basin, to provide climatic data covering long periods of time and which correlated with the data obtained for short periods of time would eventually help determinate the hydrological parameters. The representative basins have been located in various natural conditions, to underline the role that the most important factors have on discharge formation, e.g. the receptive basin s area, medium altitude, medium slope and physical-geographical characteristics such as: geology, relief, climate, soil, vegetation (Institute of Meteorology and Hydrology, 1980). 2. MATERIAL AND METHODS Tinoasa-Ciurea representative basin was established in 1969 and it is situated in the hydrographic basin of Bahlui river (fig. 1). The closest locality to the closing section is Ciurea, Iasi County. The morphometric data and forestation coefficients are presented in tables 1, 2 and 3: Table 1 Morfometric data and forestion coefficients Profile Maximum area altitude altitude (Km²) (m) (m) RUSU 1,54 123, BOLOVANI 0,50 124, CIUREL 0,17 122, HUMARIA 1, TINOASA 4,17 118, Figure 1 Location of Ciurea Tinoasa basin, Iasi County Table 2 Morfometric data and forestion coefficients Medium Streambed Streambed altitude length slope (m) (Km) ( ) RUSU 280 2,13 110,3 BOLOVANI 250,4 1,18 102,3 CIUREL 158 0,48 140,4 HUMARIA 270 2,14 111,0 TINOASA 272 2,32 103,9 Table 3 Morfometric data and forestion coefficients Medium Forestation basin slope coefficient ( ) (%) RUSU ,9 BOLOVANI ,4 CIUREL 157 0,0 HUMARIA TINOASA ,6 Available on-line at Volume 12, Issue 2,

3 Data regarding the physical-geographical characteristics of the Tinoasa-Ciurea representative basin (Cotiuşcă et al, 2009; Stătescu and Pricop, 2008; Anuarele hidrologice, ): -geology: bedrock and clays are predominant, rubles, sands and loess are also found -relief: downy, situated at the border between the Central Moldavian Plateau and the Moldavian Plain, with heights between 410 and 125 meters, and slops between 125 and 170 ; -climate: continental sometimes excessive continental, hills with predominant north-west circulation, with multiyear medium precipitations between mm and multiyear medium air temperatures of 9 ºC; -soil: brown and forest brown hectic soils, and also pseudo rendzine; -vegetation: deciduous forests are predominant. There are also meadows and pastures. In the Tinoasa-Ciurea representative basin, a complex program of observation and hydrometeorology measurements is currently carried out. On the meteorology platform (photo 1), observation and measurements at standard hours are taken: liquid and solid precipitations, air temperature (ordinary, minimum, maximum), air humidity, wind direction and speed, evaporation at soil surface. Tinoasa-Ciurea representative basin has 5 sections on Rusu, Bolovani, Ciurel, Humaria and Tinoasa (closing section) rivers, where the levels, liquid flow capacity and suspension silts are registered (photo 2). Tinoasa-Ciurea representative basin has drain plots (including a free drain plots and two concrete platforms), on which discharge capacity measurements of slope discharge are performed. In addition, the Tinoasa-Ciurea representative basin has a drilling alignment which is used for piezometric observations and measurements (photo 3). Photo 1 Images with meteorological free platform (Photo C.PRICOP, different seasons 2009) Photo 2 Measurement section images (closing section) watercourse of the representative basin Tinoasa, Tinoasa-Ciurea (Photo C.PRICOP, different seasons 2009) Available on-line at Volume 12, Issue 2,

4 Photo 3 Picture with phreatic aquifer drilling observations F19 (Photo C.PRICOP, 2009) The data obtained in the Tinoasa-Ciurea representative basin, based on the observations and measurements carried out during the last 10 years ( ), has been used for analysis and characterization of this period, and also for identification of new evolution trends of main climatic parameters. The idea for this analysis came due to the climatic changes recorded in Romania. 3. RESULTS AND DISCUSSIONS The conclusion is that the observations and measurements carried out in Romania highlight a series of signals pointing to future climatic changes, many of them having similar trends with world changes. The changes include the evolution of main climatic parameters (e.g. temperature, precipitation, moisture, flood regime), season sequence and the existence of phenomena and desertification trends. From the registered data, some aspects stand out, including: - the medium air temperature at field surface is increasing; - a slight increase of the medium annual temperature and a precipitation decrease; - extreme temperatures have been recorded; The most important modifications of the hydrological regime, doubled by their consequences, include: - the increase of evaporation in the summer season due to the air temperature increase; - the extension of small water periods and the reduction of minimum flows due to increased evaporation and decreased precipitations in summer; - continuation of drainage liquid flow in months 3, 4, 5 in the last 10 years (fig. 2 and fig. 3); - the earlier burst of nival floods and mixed floods (snow-rain) in spring, due to the desynchronization between the melting snow layer and spring rains. Using the data obtained in the last 15 years in the Ciurea Tinoasa representative basin, monthly, annual and multiyear medium flows for the 5 sections (Rusu, Bolovani, Ciurel, Humăria and Tinoasa) were determined as well as the medium number of days per month, year and multi-year when the discharge on every river was generated (Anuarele hidrologice, ). The multi-year variation of average rainfall in the representative hydrographic basin (fig. 4), are covering a long period of time 32 years, correlated with data from shorter period of time 10 years (fig. 5), helps in the determination of hydrological parameters of liquid flow. By comparing the multiyear medium values with the values recorded in 2007, we developed an evaluation of discharge for the above mentioned period. The graphical presentation of the evaluation from January to September 2007 versus the multiyear values: Figure 2 Multi-year average values of the drained liquid flow on Tinoasa River in 10 years period ( ) Available on-line at Volume 12, Issue 2,

5 Multi-year average Figure 3 The multi-year average flow of liquid drained for 19 years period ( ) Rainfall multi-year average in the representative basin ( ) Figure 4 Multi-year variation of average rainfall in the representative basin for a 32 years period ( ) Figure 5 Monthly rainfall amounts for years in representative 4. CONCLUSIONS The 2010 year from the meteorological point of view is defined to be a little bit warmer than normally and with recorded rainfall with values significantly higher than the multi-year medium values. In June, on the fond of the rainfall excess important discharges have happened on the all sections of representative basin: Rusu, Bolovani, Ciurel, Humaria şi Tinoasa when have been recorded successive floods. Also in February there was a flood that has been favored by the increases in air temperature that led to rapid melting of snow fallen in the previous months and overlapped with rainfalls. In 2010 compared to previous years they were far less dry days on this 5 rivers and the only dry month was August. 5. REFERENCES [1] Cotiuşcă, Stătescu D., Stătescu C.V., Innovative Techniques of Monitoring the Dynamics of Hydraulic Soil Properties, Generated by Climate Changes (MANAGEMENT OF TCHNOLOGICAL CHANGES, Editura Alexandroupolis, Greece, Spetember 2009; [2] Stătescu F., Pricop C., The evolution of hydrological parameters in representative basin Tinoasa-Ciurea, district Iasi BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI BULLETIN OF THE POLYTECHNIC INSTITUTE OF JASSY Tomul LIV (LVIII), Fasc. 2, 2008; [3] **** Anuarele hidrologice pentru bazinul reprezentativ Ciurea din perioada ; [4] **** Studii si cercetari hidrologice XLIX, Ed. Institutul de Meteorologie si Hidrologie, 1980 Bucuresti. Available on-line at Volume 12, Issue 2,