Vízügyi Közlemények, 1965 (47. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

'(15) which can be withdrawn from the depression zone developing around the well for continued periods

, without causing any change. In the case of thermal- and especially gaseous waters changes in the waterand layer volume may occur in the aquifer after the first period of well operation. At the surface these changes are revealed by a reduction of yield. The reduction of the yield over time (it may last from a few months to years) depends on the magnitude of elastic and dynamic resources. The method developed by the author for determining the optimum production gield which can be withdrawn for extended periods from thermal wells is based on the exponential function transformation of Maillet-Boussinesq, Eq. (6). This function is used to describe the reduction of yield of thermal wells, as demonstrated by the analysis of data measured on two wells. (The decreasing tendency of the discharge graphs for the two wells are shown in Figs. 1 and 3.) Relying on these measurements the permanent yield Q

s, cu.m/day, towards which the diminishing discharge of the well tends, is computed together with the reduction coefficient a. From these data period of stabilization in the vicinity of the well is estimated with the help of Eq. (10). By integrating Eq. (6) dynamic and elastic resources of thermal wells are determined with Eq. (12) and Eqs. (13), (14), respectively, and in the knowledge of the elastic resources the optimum production volume of the well is found. By assuming a production period the optimum production yield (Q

0pt) is thus obtained from Eq. (15).. BRIEF PUBLICATIONS (For the Hungarian text see pp. 92) 1. Illés, Gy., Eng. : Water supply in Sweden and Stockholm. Urbanization in Sweden raised water supply and sewage engineering to a very high standard. The water volume consumed by industry is 3,450 million cu.m, of which a major share falls to the celluloze and paper industry. Opportunities for water production are unfavourable since the underground resources are very meagre, most significant among these being the so-called "eskers". Characteristic data on surface watercourses and quality parameters are compiled in Tables I. and II., respectively. Groundwater recharging is of particular importanceWater consumption is covered to 56% from surface, 30% from natural underground, and 14% from artificial underground water. The architectural styling of elevated water tanks (water towers) is characterized by the correct harmony with its functional character. The great depth to which the soil freezes is a problem in pipelaying. The largest regional supply systems are those of Stockholm and Skaraborg. Water to Stockholm is delivered from the Norsborg and Lovö water works on Lake Malar (Fig. 10 — 16). Consumption figures are presented in Table III. The total length of tile urban pipe network amounts to 1,450 km and fluctuations are balanced by 6 reservoirs representing a total capacity of 125,000 cu.m. Water supply and canalization works are under the authority of the Water Supply and Canalization Department of the National Roads Office. 2. Máthé, L., Eng. : Water power development on the Yougoslavian and Hungarian—

Yougoslav border reach of the .Mura and Dráva Rivers. (For the Hungarian text see pp. 102) The Dráva and Mura Rivers form over a long distance the borderline between Hungary and Yougoslavia and present favourable power development opportunities (Figs. 1 and 3). The significance of these projects is emphasised by peak operation requirements. In order to utilize advantageous hydrological features six power stations were built in the past on the Dráva River above Maribor (Figs. 4 to 9 ), the main data of which are compiled in Table I. Projects for the Dráva River downstream from Maribor are in the planning stage (Table II.). The power potential of the Mura River between the Austrian border and its mouth could be utilized by 12 stations (Table III.). On the common Hungarian —Yougoslav reach five stations could be built in three groups (Table IV.).