Considerations Regarding Water Supply in Dolhasca Town, Suceava County Rodica MACALEŢ, Maria CĂLIN, Tudor MUNTEANU, George DUMITRAŞCU
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CONSIDERATIONS REGARDING WATER SUPPLY IN DOLHASCA TOWN, SUCEAVA COUNTY RODICA MACALEŢ, MARIA CĂLIN, TUDOR MUNTEANU, GEORGE DUMITRAŞCU National Institute of Hydrology and Water Management, 97, Bucuresti-Ploiesti Road, 013686, Bucharest, ROMANIA [email protected], [email protected], [email protected], [email protected] Abstract. Geomorphologically, Dolhasca town is located in the east-southeastern part of Suceava county, in the contact area of Suceava Plateau with terraces from the right part of Siret river at the confluence of the Siret and Şomuzul Mare rivers. Geologically, the studied area is located on the Moldavian Platform and is characterized by the presence of Sarmatian and Quaternary deposits. Hydrogeologically, on the basis of data provided by wells located in this area, two types of aquifers: shallow and confined were separated. Shallow aquifer has been intercepted in the meadows of the Siret and Şomuzul Mare rivers and consists of one or two porous-permeable layers, in the range of approximately 3-16 m depth. This aquifer has been identified in four wells belonging to the National Hydrogeological Network. Confined aquifer is accumulated in the Lower Sarmatian (Volhynian) deposits, in a depth range of about 20-250 m. Drinkable water sources that supply the Dolhasca town are made from two production wells: Poiana production wells constituted by six wells and Budeni production wells constituded by two wells. For delimitation of the sanitary protection areas for Budeni and Poiana production wells, the Wyssling analytical method was used. The hydrogeological protection perimeter boundary of two production wells was drawn taking into account the geomorphological conditions, the hydrographic network but also the regeneration area of groundwater resources. Key words: shallow, confined, aquifer, well, production wells 1. INTRODUCTION part of Moldova-Suceava interstream. It starts at an altitude of 528 m near its northern edge and to the south Fălticeni Dolhasca town, made of eight villages (Dolhasca, Budeni, Plateau, reaching Paşcani town, where Falticeni Plateau nar- Gulia, Poiana, Poienari, Probota Siliştea Nouă and Poiana rows because of the common terrace area of Moldova and Valley) is located in the east-south-eastern part of Suceava Siret rivers. county, on the contact area between Suceava Plateau and A feature of the Suceava Plateau is the large extent of the the terraces from the right part of Siret river, at the conflu- structural Şomuzul Mare and Somuzul Mic plateaus, which ence of the Siret and Şomuzul Mare rivers. are fragmented by deep valleys of 100-150 m relative depth. Water supply of this town is provided by two production Siret Valley is a broad valley having a system of five large well fields : Poiana, with 6 wells and Budeni, with 2 wells. terraces on all its course in Suceava county (almost 100km). 2. GEOMORPHOLOGICAL CONSIDERATIONS In the Suceava county, the Siret Valley is 6-8 km wide, and in the area of confluence with Suceava transforms it in an al- Geomorphologically, Dolhasca town is located within luvial plain with over 12 km width. the contact area between Suceava Plateau (Fălticeni Plateau In the confluence area of the two rivers, four terraces of subunit) with the terraces of the right part of Siret river, at Siret river (180, 130, 50 and 25 m above the river) are the the confluence of Siret river with Şomuzul Mare river (Fig. 1). same as those of Suceava river. The age of the terraces is Qua- Fălticeni Plateau, having a north-west - south-east orien- ternary and the most extensive terrace is that one of 25 m tation and a maximum width of 20-22 km, lies in the southern (Pascani). Geo-Eco-Marina 16/2010 129 Rodica Macaleţ, Maria Călin, Tudor Munteanu, George Dumitraşcu – Considerations regarding water supply in Dolhasca town, Suceava county Hydrologically, Dolhasca town is located in the Siret river deposits with Carpathian orogenetic this thickness reaches basin which is managed by the Water Basinal Administration arround 2000 m. of Siret, headquartered in Bacău. Middle Sarmatian (Bessarabian) 3. GEOLOGICAL CONSIDERATIONS Bessarabian deposits outcrop only on small areas at the southern border of the region. They form interfluves’ peaks, The studied area is part of the great geological unit of the with the greatest development in the Dealul Mare massif, Moldavian Platform and is characterized by the presence of situated east of Siret river and south of Boroaia village; at the Sarmatian and Quaternary age deposits. In the following the edge of the Subcarpathian area these deposits appear as a main characteristics of these deposits are described. narrow band. Lower Sarmatian (Volhynian) The Bessarabian deposits overlay conformably the Vol- Volhynian deposits have a largest development and hynian ones as it can be seen in Dealul Mare area and Tătăruşi presents lithological monotony, being made mostly of clays region and consists of sandy clays and sands, with rare inter- and sands, in which thin levels of sandstones, calcareous calations of sandstones and oolithic limestones. sandstones and oolitic limestones are distinguished. Nearby West of Siret Valley there was identified only the lower Fălticeni town there is a coal complex consisting of clays with part of Bessarabian deposits in dominantly sandy facies. Fria- thin intercalations of coal. ble and poorly oolithic sandstones intercalate into the sands At Arghira (about 15 km northwest of Dolhasca town), on from the upper part of peaks located north of Tătăruşi locality the profile of Muscalului Valley (Ionesi, 1968) these deposits situated about 9 km south of Dolhasca town.The thickness of are represented by compact clays and sandy clays, contain- Bessarabian deposits is about 200m at the east of Siret Valley and increases to the west, towards the Subcarpathian area. ing numerous fauna, constituting lumachelle levels, which abound both in bivalves and gastropods, on which there is Quaternary deposits a package of sandstones with thin intercalations of sand, and Quaternary deposits are ascribed to the Pleistocene (old on the top it consists of calcareous sandstones which per- colluvia and terraces), Upper Pleistocene-Holocene (deluvial tains to the Arghira I lumachellic sandstone horizon. deposits) and Holocene (actual and subactual alluvia). Pleis- At Lespezi (12 km south of Dolhasca town), from an al- tocene deposits enter within the composition of the Siret titude of 200 meters, Upper Volhynian deposits consist of river terraces and are represented by alluvial formations. quartz sands followed by a level of fossiliferous sandstone Siret terraces, four in number in the surroundings covered with medium grain sands. Towards the top part of of Dolhasca locality were highlighted by Sîrcu (1955). Volhynian deposits two levels of quartziferous sandstones Thus, Siret upper terrace (100 m) appears at Tudora (10 km occur (Ştefan, 1997). north of Dolhasca) and Lespezi. Lithologically, in the com- The thickness of the Volhynian deposits increases gradu- position of this terrace occur gravels with Carpathian origin ally from east to west, so that in the contact area of these elements. Fig.1 Geomorphological map of the studied area 130 Geo-Eco-Marina 16/2010 Rodica Macaleţ, Maria Călin, Tudor Munteanu, George Dumitraşcu – Considerations regarding water supply in Dolhasca town, Suceava county Middle terrace (60 m) has a large development, also, at The shallow aquifer was highlighted by wells of water Tudora and Lespezi. Lower terrace (20 m) has in its composi- supply as well, wells belonging to Budeni and Poiana pro- tion gravels and loess and is developed at Lespezi. Low ter- duction well fields. race (7-8 m) consists of gravels and it formed as a result of Budeni F1 well, with a 15.0 m depth, screened the interval alluvial processes. between 8.0-10.5 m (sand and gravels), with a yield of 1.6 l/ Upper Pleistocene-Holocene deposits are represented by sec, for a 0.40 m draw-down. Budeni F 2 well with a 15 m to- slope deluvial deposits (silts, clays, sands and gravels). tal depth opened the porous-permeable layer (sandy gravel) situated at a depth 8-11 m . At the testing moment F2 had a Holocene deposits with the largest spread are represent- yield of 2.0 l/sec, for a 0.5 m draw-down. ed by alluvial deposits which form the Siret river valleys and its tributaries. The shallow aquifer was highlighted by six wells of Poiana production wells, wells with depths ranging from 13.0 to 16.0 4. HYdrogeological considerations m. The screening intervals were at depths ranging from 6.20 to 10.80 m. Lithologically, shallow aquifer is represented by Based on data from wells carried out in Dolhasca and its gravels and boulders (fig.2). surroundings two types of aquifers were separated: shallow and confined. Water recharge of the shallow aquifer developed in the Siret meadow is done both by the rainfall and directly from In the meadow area of Siret river and Şomuzul Mare right river. tributary of Siret, at the base of deluvial deposits and some- times at the upper part of the Sarmatian deposits, the wells intercepted the shallow aquifer, represented by one or two porous-permeable layers, within a depth interval of about 3 -16 m. The confined aquifer is located in the Lower Sarmatian (Volhynian) deposits within a interval of about 20 - 250 m depth. In the following the main characteristics of wells drilled for tapping of the shallow and confined aquifers in the inves- tigated area are presented. Shallow aquifer The analysis of the existing groundwater data for Dol- hasca area have identified both wells belonging National Hydrogeological Network (4 monitoring wells) as well as pro- duction wells (4 wells). The four observation wells (F1-F4), which were drilled in 1970, have the following characteristics: • F1, with a depth of 21 m, provided a yield of 1.9 l/sec (for 0.26 m draw-down).