Hidrológiai Közlöny 1972 (52. évfolyam)

3. szám - Dóra Tibor: A Kiskörei Vízlépcső hatása a Tisza vízjárására és környezetére

Dóra T.: A Kiskörei Vízlépcső hatása Hidrológiai Közlöny 1972. 3. sz. 109 e) Vízerőhasznosítás A Kiskörei Vízlépcsőnél megvalósuló 28 MVV-os kapacitású korszerű csőturbinás vízerőmű 103 millió kWó évi energiát termel. f) Hajózás A Kiskörei Vízlépcső megépítése után a Tisza Kisköre—Tiszalök közötti 120 km-es szakasza az egész hajózási idényben a IV. kategóriájú hajózó utak feltételeit kielégíti. Az évi hajózási napok száma átlagosan 270-re emelkedik. g) Vízparti üdülés A kiskörei duzzasztás következtében mintegy 127 km

2 felületű tó keletkezik, amely a jelenleginél kimagaslóan kedvezőbb feltételeket teremt a vízisportok, üdülés, sport —- horgászat számára. A kiskörei tározótó az ország második legnagyobb tava lesz. Bár a tározóként való hasznosítás az üdülési idényben a vízszint csökkenésével jár, azonban a partok mentén húzódó telt élőmeder és a természetesnél sokkal mérsékeltebb vízszintingadozás már kitűnő feltételeket teremt a vízparti üdülés számára. A Tisza középső szakaszán megvalósuló kiskörei komplex létesítményrendszer lényeges befolyással lesz a Tisza középső szakaszának vízjárására. A várható változások előzetes felmérése és értékelése sokrétű előzetes vizsgálat alapján történt. A várható változások ismerete alapvetően befolyásolta és megalapozta az elvégzett tervezési munkát. IRODALOM VÍZITERV: Kiskörei Vízlépcső és Öntözőrendszereinek Főművei. (Tervszám: 14084) Kiviteli terv, kézirat. 1970. Effects of the Kisköre Barrage Project on the regime and environment of the Tisza River By Dóra, T. The changes brought about by the Kisköre Barrage and the structures built eorrolary thereto, will be considered in accordance with the various branches of water management. 1. The natural streamflow regime of the Tisza River. The section of the Tisza River principally affected by the project is the backwater reach created (Fig. 1). For describing the streamflow regime, the hydrologic data recorded from 1901 to 1960 for the section of the barrage have been studied and corrected where this was found necessary. The estimated typical flood discharges have been compiled in Table 1. a) Flood control. Over the 120 km long backwater reach the existing flood levees (Fig. 2) are capable of withstanding floods with a recurrence probability of 2.5% at a very,slight margin of safety. At times of floods large areas along the levees are inundated by underseepage and leakage waters and the groundwater table is undesirably raised. b) River regulation. Channel erosion is greatly promoted by fluctuations in the groundwater level (Fig. 3), resulting from variations in river stage (the range being 11 m). Following a rapid fall of stage the soil particles are more readily displaced and more susceptible to scouring by flow in the river. The present practice consists of controlling channel erosion by brushwork structures, sometimes combined with rip-rap lininge. Under natural conditions the river is ice-covered for 60 days yearly on the average, and the level of ice-jam floods corresponds to highwaters of 4 to 5 years recurrence frequency. The sediment regime is balanced, with slight bedload transportation. Navigation depends on river stage, regulation being necessary for ensuring navigation on the river. c) Land drainage. The maps of inundations in flood years (Fig. 1) indicate the damages to areas along the levees. The capacity of lifting stations at the end of drainage canals is insufficient. d) Water uses. The bulk of the natural resources available in the Tisza River is used for meeting the demands of agricultural consumers. In view of the wide fluctuations in discharge and of the capacity of pumped diversions already existing, no further development is considered possible. The resources available are of a satisfactory quality, the conditions of aquatic life being ensured. c) Hydroelectric power. At the present the power potential of the backwater reach above the barrage is not utilized. d) Navigation. In its original condition the river section under consideration is seen to meet the criteria for IV-th class waterway's over no more than 100 to 150 days annually. e) Riparian recreation. The wide range of stage fluctuations did not favour recreation on the banks. 2. Changes in streamflow regime The regime of the Tisza River will be controlled in the backwater reach by the Kisköre Barrage (Fig. 4) and by the manner in which the reservoir formed upstream thereof is operated. The main parts of the barrage are the weir, which is capable of maintaining a level at El. 91.20 m AOD, the hydroelectric station, capable of discharging 560 cu.m/sec the navigation lock meeting the specifications for IV-th class waterways and the flood gate helping to pass flood waves. The flood bed of round 40 km length will be transformed into a reservoir of 400 million cu.m live storage volume. Depending on the arriving discharge, different waterlevels are maintained at the weir, as indicated in Fig. 5. a) Flood control. The weir is opened as soon as the discharge in the river exceeds 1800 cu.m/sec. The flood discharge of 1% probability, i.e., 4032 cu.m/sec is passed by raising the level by no more than 13 cm, so that the effect of the barrage on flood stages is very slight. The existing flood levees will be reinforced in order to make them suitable to retain the stored water (Figs. 6 and 7). The levees will have 6.0 m wide crests, the freeboard above the highest retention level and the 1 % probability flood level being 2.0 and 1.5 m, respectively. Protection from wave scouring is provided by a 20 wide strip of planted reeds. The levees are dimensioned for a factor of safety n— 2 at highest retention level and n= 1.5 at the flood level of 1% probability. Underseepage-, leakage- and surface waters are collected and groundwater is prevented from rising bymeans of an intercepting canal running parallel to the levee at a distance of 80 to 100 m therefrom. The control system is based on control centers spaced 15 to 20 km from each other. These centers are connected to the road network by paved roads. b) River regulation. The range of waterlevel fluctuations will be reduced in the backwater reach, channel erosion will be retarded, the velocity of flow will be reduced and 300,000 to 500,000 cu.m of sediment is likely to be deposited, which must be removed by dredging. The duration of the ice cover in the backwater reach is expected to increase to 80—90 days/year. In winter a lower retention level will be maintained and the natural levee along the channel will prevent the ice in the reservoir from entering the channel (Fig. 8). Ice conditions over the section downstream of the reservoir will be improved. c) Land drainage. The canal system along the reservoir will be interconnected with the system of drainage canals running perpendicular to the Tisza River and the added capacity of the new automatically operated pumping stations will considerably accelerate the removal of excess waters from the surrounding areas. d) Water uses. The project will affect fundamentally