Assessment of a River Basin Water Resources System in Bulgaria

Water Management Balances (WMB) Assessment of a River Basin Water Resources System in Bulgaria Stiliana YANCHEVA, Anna YORDANOVA, Maria TEMELKOVA Institute of Water Problems at Bulgarian Academy of Sciences Sofia, BULGARIA Email: [email protected] A b s t r a c t The paper present the received results from water management balance (WMB) for existing multi - purpose water resources system (WRS) in the Archar and Vidbol river basins – two important feeders of Danube river in North-West Bulgaria. It is done a short description and are marked the specific features of present water resources use in the river valley. For certain points from the river network are determined the main statistical characteristics of natural river flow (for the period 1961 - 2004 year). Based on the developed scheme for water use and different variants of the individual users needs are made water management balances (WMB). Experimental simulations researches for WMB are carried out with prepared input information for the inflow and water demand. Sequences for the inflow and irrigation demand in the relevant points are 44 years long by months. The results for different variants of WMB are analyzed and it is made assessment of water availability of different users. The Archar and Vidbol river basins problems in result of the economical, political and climate changes are discussed. Key words: river basin, water management balance, water supply availability, water resources management, operation, management, computer model, simulation General principles in WMB 1. Water management balance (WMB) is the correlation between a flow and water consumption for: • fixed territorial unit from earth surface; • fixed time interval; • recognizing water human activity 2. Two parts of WMB – flow and water demand, giving his income and outcome part are forming and changing in time and space under influence of water human activity that includes: • hydro technical construction of river streams with regulation of inflow; • water utilization, according to the specifics of different branches of the water economy – industry, irrigate, water supply, hydro power etc.; • all activities changing the environment, connected with water. 3. Comparison the income to the outcome: • is solution in which are reflecting the main sides of the using and distribution process of water resources in the water economy, • It is not simple arithmetic operation, simple accounting balance, simple water balance. 4. Comparison the flow to water demand is going on : • the space ( in territory and in height) • quantity and quality (correspondence with the requirements of the consumers) • the time i.e. for given level of economy development • the given time interval. BALWOIS 2008 – Ohrid, Republic of Macedonia – 27, 31 May 2008 1/13 General activities in WMB First: Fixing the territorial unit for which the WMB is developing (water management system, river basin, parts from it, the whole country); Second: Assigning the economical level for which is developing WMB (at present or in the perspective, in conformity with the stage of water management investigations – operating, designing, planning); Third: Choosing the time interval for developing WMB (year, month or another wanted time interval); Forth: Composition of water management scheme for using the water resources which is the main requirement for converting the water balance for given territorial unit in WMB. There is no WMB without accepted scheme for water use. Following the succession FIRST: In this case are developed WMB for ARCHAR and VIDBOL river basins; SECOND: WMB are developing for different variants of inflow and water demand, for two stages: at present and in perspective till 2015-2020; THIRD: It is accepted the comparison inflow to water demand to be in months FORTH: Because the two river basins are hydraulically connected, they are considered as one water management unit, for which is elaborated scheme for water resources use. General database of Archar and Vidbol river basins 1. Description of the real scheme for water use Archar and Vidbol rivers are feeders of Danube river. They are situated in the North-west part of Bulgaria. Water management of the two rivers is connected and in developing the WMB the two river basins are considering united in one joint scheme. Main water consumer is the ”Rabisha” Irrigation System, which is fed from the lake Rabisha reconstructed as a reservoir (”Rabisha” reservoir – total volume 42 mln.m3). The reservoir is feeding by artificial way, and for catching and leading the water to it are constructed three derivations. Derivation ”Vidbolska”, catching and leading the water of Vidbol river and four of its feeders with the help of 5 constructed headworks (each with equipped for a discharge of Q = 1.8 m3/sec.). Derivation”Archar” (equipped for a discharge of Q = 2.7 m3/sec), is starting from the ”Raianovtzi” reservoir. The reservoir is situated on the Archar river next to the Raianovtzi village and its total volume is 0.406 mln.m3. Third derivation (equipped for a discharge of Q = 0.45 m3/sec), is including from the Derivation”Archar” next to the entrance shaft of the culvert siphon on Archar river. It is starting from the ”Oshane” reservoir. The “Oshane” reservoir is situated next to the Oshane village on the Oshane dere river and its total volume is 0.609 mln.m3. The joint part of the derivation “Vidbol” and “Archar” has a discharge of Q = 4.5 m3/sec. The intake from the reservoir is carried out through a water tower at the outlet of the reservoir, which is reconstructed as long free flow tunnel (equipped for a discharge of Q =5 m3/sec.). In the begging of the tunnel is the Pumping Station “Tolovitza” (equipped for a discharge of Q = 1.87 m3/sec.). After the tunnel starts the canal M2, The pressure pipeline of the Pump Station next to the its outlet shaft continues in the main canal M1. From the canal M1,passing along the Rabisha ridge, next to the Pump station “Rabisha” begin the canal P-1. Canal M1 reach to the Pump Station “23 September” (equipped for a discharge of Q = 450 l/sec.), From the outlet shaft of the Pump Station “23 September” starts canal P-10. Canal M2 goes to the North, crosses Vidbol river with seg-pipe (equipped for a discharge of Q = 3.2 m3/sec.). The canal from the outlet shaft of the seg-pipe goes to the left and reaches the Pump Station “Shishmanovo” (equipped for a discharge of Q = 0.95 m3/sec.). To the right of the BALWOIS 2008 – Ohrid, Republic of Macedonia – 27, 31 May 2008 2/13 outlet shaft of the seg-pipe starts canal P-12. The biggest facility on this canal is the seg-pipe ”Virovete”. From the entrance shaft of the culvert siphon goes canal 3-CD-1. The size of the attached areas (constructed and with fitted infrastructure), irrigated from these canals is given in Table № 4. Along the Archar river and its feeders are constructed many catchments from surface and underground water in the regions of the village of Salash, the village of Oshane, the village of Rabisha, the village of Raianovtzi, the village of Darjantzi, the village of Bela, the village of Dimovo, which provides the villages with drinking water and water needed for industry. On the Salashka river (right feeder of the Archar river), in its upper upstream, on its feeder Gradska river next to the village of Dubravka is constructed water reservoir “Dubravka” (total volume 0.730 mln.m3) , which water is used for irrigation of the areas in Irrigation field Dubravka”. In the Vidbol river basin is interesting for the water management its left feeder-Gramadska river. The two biggest constructed water reservoirs on it are”Farfun” reservoir (total volume 0.500 mln.m3) , used for fish-farming and “Bojuritza” reservoir (total volume 1.43 mln.m3) used for irrigation of the areas of Irrigation field ”Bojuritza” and fish-farming. Catchment next to the village of Sinagovtzi takes water from Vidbol river and through Main Irrigation Canal irrigates Irrigation field “Sinagovtzi”. In the Vidbol river basin and its feeders, next to the villages Boianovo, Rakovitza, Sinagovtzi, Jeglitza, Milchina luka etc. there are constructed outlets from surface and underground water for providing with water the villages in the river basin. 2. Description of the calculate scheme for water use Basing on the real scheme for water use is developed calculate scheme, which is the base of developed WMB for the two river basins (Fig.1) and including: • From the water management point of view for Archar river and Vidbol river are important: Archar river Salashka river Oshan dere river Vidbol river Gramadska river Svadbiste river etc. • In 10 points on the river network is restored the natural regime of the river flow (rows in months from 1961 to 2004), (on Fig. 1 is circle with number from 1 to 10 in it) (Table №1) Table №1. Statistical parameters of the river flow rows № № Name Q medn Cv Cs no annual de (m3/sec) 34 1 Archar river (mouth) 1,813 0,392 -0,201 29 2 Salashka river (feeder of Archar river-mouth) 0,786 0,392 -0,201 23 3 Salashka river ( feeder of Archar river-Vestitza village) 0,571 0,392 -0,200 8 4 Oshane river (damn wall of Oshane water reservoir) 0,104 0,392 -0,200 9 5 Raianovtzi reservoir (damn wall) 0,338 0,391 -0,197 1 6 Archar river (catchment Rianovtzi) 0,247 0,391 -0,199 16 7 Vidbol river (Vidbol catchment, next to Rakovitza village) 1,134 0,405 0,572 4 8 Gramadska river ( left feeder of Vidbol river) 0,261 0,405 0,567 13 9 Vidbol river (mouth) 1,095 0,405 0,567 7 10 Oshane river (damn tail of Oshane water reservoir) 0,094 0,392 -0,196

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