Conservation of the geological environment when constructing hydraulic structures

Abstract

624.131.6:627.8 and L. A. Molokov Hydroelectric projects, reservoirs, and large canals are the largest objects created by man, and their effect on the environment extends over considerable territories and encompasses the basins of large rivers or wide zones along canals, i.e., has a regional character. With the existing scale and rate of constructing hydraulic structures (at present about i0,000 reservoirs with a volume of more than 0.i km s have been constructed worldwide, of which more than 250 are in the USSR) [i, 13], the damage inflicted by these structures on the environment is becoming comparable to the reserves of certain natural resources.For example, just the losses from flooding or depreciation of the quality of lands as of 1974 amounted to about 85,000-95,000 km 2 [4], which is comparable to the land reclamation plan in the country (draining and irrigation) up to the year 1990 [9].A specific feature of the construction of hydraulic structures is, in particular, that it is practically impossible to eliminate its adverse effect on the environment and, as a rule, it occurs imreversibly {e.g., flooding of lands), although many types of it can be~regulated and the problem usually reduces to the compilation of economic evaluations of the environmental damage from constructing the structures and the corresponding cost to prevent it. Some of these evaluations are rather conventional (e.g., the cost of various soils, forests, etc.); others in the near future can change substantially, and it is difficult to predict the extent of the change.Therefore, a study of all parameters of the environment and the most complete possible evaluation (at least in a physical expression) of the remote consequences of constructing large hydraulic structure are now becoming the top-priority problem.In itself this problem is not new, but now, compared to the 1950s when the country acutely needed first and foremost a boost of the energy base, its urgency has increased sharply. Moreover, before the 1950-1960s, when there we=e few large reservoirs and their cascades, our knowledge about their effect on the environment was rather scanty and largely theoretical. Now the situation has changed substantially: for many types of effects and certain particular processes there are quantitative evaluations or studies based on long-term experience in operating large structures and cascades of =eservoirs.During this same period environmental damage has increased markedly also from other human engineering and economic activities (the mining and processing industry, cities, irrigation systems, etc.) and therefore at present it is necessary to examine the adverse effect of constructing hydraulic structures against the background of the overall anthropogenic impact in this direction [8]. At present there are no quantitative total and branch (of the economy) evaluation of the indicated adverse impact on the environment, and therefore it is extremely difficult to assess the "contribution" of the construction of hydraulic structures proper:to thi...