Vízügyi Közlemények, 1937 (19. évfolyam)
3-4. szám - Szakirodalom
19 several hundred metres. A special difficulty lies in the fact that most of the towns and communes are settled on large areas with relatively scattered populations, therefore the costs of a central water supply are too great, These difficulties explain the fact that of the 57 towns of Hungary only 27 are provided with waterworks (Table 1), and of the small communes only 24 (Table II). Only 24 per cent of the 9 million population of the country are served by central waterworks. But many towns and villages are provided with private water conduits established by well-companies (Table III), forming many small units independent of one another. This system does not solve the problem of watersupply as perfectly as central waterworks do, and therefore it would be desirable to advance the construction of central waterworks instead of furthering private conduits. In communes not provided with waterworks the State Hygienic Institute exercises a control over the wells and attempts to improve small water supplies by establishing standard wells. According to the statistical data of 1925, 178 communities reported bad drinking water. Meanwhile the Hygienic Institue has constructed good wells in about 40 to 50 communes, and the improvement of conditions in others is in progress. To characterise the difficulties of water supply in Hungary, it may be mentioned that there are 6000 deep-bored wells with an average depth of 200 to 300 metres, and many wells deeper than 1000 metres have been boied to secure drinking water. Considering that in this country the construction of about 50 to 60 new waterworks would be necessary, and the costs of these works cannot be estimated without designing them in detail, the author has worked out a theoretical method, by the aid of which the costs of a waterwork can be estimated with a certain accuracy from the number of inhabitants and the density of population per hectare. American authors have stated that the construction costs of waterworks, especially in small towns, are for the most part made up of the cost of the pipe system (fig. 4). But the cost of a pipe system can be derived from the relation existing between the length of pipe falling to one inhabitant and the density of population. This relation is illustrated by an equicrural hyperbola (fig. 2). The formula serving to compute the costs is s 2-Ő L y P D 100 u where S = the total construction costs, L = the number of inhabitants to be supplied with water, y = the length of pipe falling to one inhabitant, on the scale of the 2600 diagram (fig. 2), y = — -j- 25, where x = the density of population per hectare, I'd = the prime and laying costs of one metre of pipe of average diameter, a = a factor depending on the number of inhabitants, to be taken from figure 4. On the basis of this formula the construction costs can be quickly and simply calculated without preparing desings in detail. The length of pipe falling to one inhabitant at different densities of population is suitable for determining, under
