Hidrológiai Közlöny 1991 (71. évfolyam)

1. szám - Sárváry István: A Hévízi-tó utánpótlódásának kérdései

20 HIDROLÓGIAI KÖZLÖNY 1991. 71. ÉVF. 1. SZAM Problenis of recliarge ío Laké Hévíz Sárváry I. Abstracl: The depression caused by draining the bauxité mines at Nyírád has encroached upon the originál subsurface catcliment of Laké Hévíz, which comprises at the present only the open-karst areas of the Keszthely Mountains and the surface catchments related thereto (Fig. 1.). During the same period successively growing flows have been pumped alsó from the wells sunk around the laké, as a consequence of which the stationary water levels have dropped and the hydraulic gradients towards the laké spring have decreased (Fig. 2.). The dry weather of the last two decades (Fig. 3.) has alsó contributed to decreasing the inflow to Laké Hévíz. The rate of reduction has at the same time been moderated by the dam built at Zalaszántó, round 10 km to the North of the laké, which has added a 75 km

2 large surface catchment to the underground (karst) recharge area to the lake. From the reservoir created by the dam seepage to the karst depends on the water level (Fig. 5.). Detailed observations were carried out in 1989 on the pumped- and observation wells around Lake Hévíz (Fig. 7.). By operating the wells of the waterworks intermittently, changes were induced in the karst water table (Fig 8.) and the effects thereof were observed in the other wells (e. g. Fig. 9.). Daily operation of the thermal wells (Fig. 10.) and raising the water level twice each week in the nearby eel breeding farm (Fig. 11.) were demonstrated to have significant impacts on recharge to the lake. Compensation for the lack of rainfall and snow, as well as for the impact of mine drainage could be provided by artificial recharge to the karst water. The engineering solution is shown in Fig. 12. Thermal water to Lake Hévíz flows from the perched groundwater, which in turn is recharged from the direction of the Keszthely Mountains. The location of the perched karst water is shown in Figs. 13. and 14. Keywords: thermal karst, karst water, bauxité mining SÁRVÁRY ISTVÁN Szakmai működésének leírását a Hidrológiai Közlöny 1990. évi 2. számának 100. oldalán közöltük.