Hydraulic Engineering Installations

installations intended to utilize water resources (rivers, lakes, seas, groundwater) or to combat the destructive action of water. Depending on location, hydraulic engineering installations can be of the marine, river, lake, or pond type. A distinction is also made between surface and underground hydraulic engineering installations. Depending on the use made of the water, such installations are classified as power-generating, reclamation, transportation, timber-rafting, fishery, water-supply and wastewater, water-resource, municipal development, and sports installations.

A distinction is made between general hydraulic engineering installations used for almost all types of water utilization, and special installations, built for some single type of water utilization. General installations include headworks, water-conduit, control, storage, and runoff installations. A head-work creates a pressure or differential in water level above and below a structure. Such installations include dams (the most important and most widespread type of hydraulic engineering installation), which block off river channels and river valleys in order to raise the level of the water backed up behind them; dikes (or levees), which protect adjacent land areas and prevent their inundation during floods or periods of high water on rivers and during high tides and storms on seas and lakes.

Water-conduit installations deliver water to specific points and include canals, hydraulic tunnels, flumes, and pipelines. Owing to the natural conditions in which they are located and the need to cross lines of communication and to ensure safe operation, some of these installations, such as canals, require the construction of other hydraulic engineering installations that constitute a special group of canal installations (aqueducts, culvert siphons, bridges, ferry crossings, control gates, spillways, ice shute passes).

Control (corrective) hydraulic engineering installations serve to change and improve the natural flow conditions of water currents and to protect river channels and banks from erosion, silting, and ice action. River control work involves the use of current-direction structures (such as semidams, baffles, and dikes) and bank strengthening, ice-control, and ice-holding installations.

Water-storage (water-impounding) hydraulic engineering installations are built to take in water from a source and to direct it into a conduit. In addition to ensuring an uninterrupted, plentiful, and dependable supply to water users, such installations protect water conduits from ice, sludge, sediments, and the like.

Hydraulic engineering installations for water runoff release excess water from reservoirs, canals, and head bays. They can be built in channels or on the shore, on the surface or underground; they permit partial or complete draining of the body of water involved. In order to control the amount of water released, runoff installations have hydraulic floodgates. Automatic overflow installations are also used where small amounts of water are to be released. They operate automatically when the level upstream is higher than required. Such installations include spillways (without floodgates), spillways with automatic floodgates, and siphon-type overflows.

Special hydraulic engineering installations include installations for the utilization of waterpower, such as the buildings of hydroelectric power plants and head bays; installations for water transportation, such as navigation locks, boat elevators, and lighthouses; installations for handling ships, raft routes, and log chutes; port installations, such as moles, breakwaters, piers, moorings, docks, covered berths, and slips; reclamation installations, such as trunk and distribution canals and control gates for irrigation and drainage systems; fisheries installations, such as fish ladders, fish elevators, fish-breeding ponds, and the like.

In a number of instances general and special hydraulic engineering installations are combined in a single complex, as is the case with a spillway and hydroelectric power plant building (a so-called multiple-purpose hydroelectric power plant) or other installations that carry out several functions at the same time. When water management measures are carried out, hydraulic engineering installations serving a common purpose and situated in a single area constitute complexes called hydroengineering complexes. Several hydroengineer-ing complexes constitute a water management system, for example, a hydroelectric system, transportation system, or irrigation system.

On the basis of their significance in the national economy, hydraulic engineering installations (construction projects) in the Soviet Union are divided into five classes in terms of capital value. In the first class are basic, permanent hydraulic engineering installations of hydroelectric power plants with a capacity in excess of 1 million kilowatts; in the second class are hydroelectric power plants with a capacity of 301,000 to 1 million kilowatts, installations on the longer principal inland waterways (such as the Volga River and the V. I. Lenin Volga-Don Canal), and installations at river ports with a cargo volume in excess of 3 million standard tons; in the third and fourth classes are hydroelectric power plant installations with a capacity of 300,000 kilowatts or less, installations on major inland waterways and local waterways, and installations at river ports handling 3 million standard tons of cargo or less. In the fifth class are temporary hydraulic engineering installations. Reclamation installations are also divided into five classes on the basis of capital value. Depending on the class, degrees of reliability of hydraulic engineering installations are indicated in plans, that is, margins of safety and margins of safety against buckling are given, as well as estimated maximum flow rate, quality of building materials, and the like. In addition, the volume and nature of exploratory work, design work, and research work are determined on the basis of capital value class.

Characteristic features of hydraulic engineering installations depend on the effect upon them of water flow, ice, silting, and other factors. This effect can be mechanical (such as static and hydrodynamic loads and underseepage), physical and chemical (wearing of surfaces, corrosion of metals, lixiviation of concrete), or biological (rotting wooden structures, boring into wood by living organisms). The conditions under which hydraulic engineering installations are built are complicated by the need for passage through the installation of the so-called construction discharges of the river, of ice, floating timber, and ships during construction (usually for a period of several years). The erection of hydraulic engineering installations requires extensive mechanization of construction work. For the most part monolithic and large precast structures, and more rarely prefabricated and standardized items are used, depending on various unique combinations of natural conditions, such as topographic, geological, hydrological, and hydrogeological conditions. The influence of hydraulic engineering installations, especially a headwork, extends over large territories within which some land areas are inundated, the water table rises, and shorelines are destroyed. For this reason, the construction of such installations necessitates high-quality work and assurance of a high degree of design reliability in installations, since damage to hydraulic engineering installations has severe consequences in terms of loss of human life and the loss of material assets. (For example, damage to the Malpasset Dam in France and to the Vaiont Reservoir in Italy resulted in loss of human life and the destruction of towns, bridges, and industrial facilities.)

Improvement in hydraulic engineering installations depends on further development of hydraulic engineering and, in particular, on theoretical and experimental research on the effect of water on structures and their foundations (the hydraulics of currents and structures, seepage), the study of the behavior of bedrock and nonbedrock when used for foundations and as building materials (the mechanics of soils, engineering geology), and the development of new types and designs for hydraulic engineering installations (high-pressure head dams of lower weight, tidal power plants) that require less expenditure of time and resources for their construction.