A STUDY OF COAST PROTECTION CONSTRUCTIONS BUILT WITH THE USE OF RECYCLED CONSTRUCTION MATERIALS AND THEIR NEGATIVE IMPACT

Different types of materials are used in hydraulic structures and coast protection constructions. These materials can be of natural (e.g. stone) and artificial origin (concrete, metal). The main trends typical for building construction now are as follows: cutting a share of natural materials and reusing waste products of dismantling construction objects. As a result of recycling it is possible to produce building materials that look like and have properties characteristic of natural stone materials, gravel, in particular. While gravel is being processed, it is possible to predict that it would obtain such characteristics as grade, frost resistance and strength. Reuse of recycled construction materials is a challenge, because this type of waste can hardly be reduced in volume and requires considerable space for burial. We propose to use gravel produced by processing in hydraulic engineering objects, i.e. in coast protection constructions. For that, we analyzed waste materials characteristics to justify their use in hydraulic structures. The research proved that strength of gravel produced by processing was sufficient enough. On the other hand, its frost resistance and fineness did not satisfy the requirements to materials used in coast protective structures. Besides, the construction of such structures causes water pollution as inert materials placed in waterbodies increase water turbidity. As a large part of the structure is located directly in the waterbody, during the period of the construction inert materials are supposed to be dumped. In this period the water body is filled with a significant amount of fine particles, which leads to an increase in turbidity at the construction site. Thus, we come to the conclusion that it is possible to reuse recycled construction materials in hydraulic engineering structures only on condition of their additional after-treatment processing. We offer to mix gravel produced by processing with cement mortal. As a result we obtain no-fines concrete, which is further processed by hot procedure (with bituminous materials). No-fines concrete can be produced in the form of precast units of 1,4×1,4×0,5 m. The use of prefabricated units will allow to avoid waterbody pollution and protect it from fine particles. Further processing by bituminous materials will enhance its frost resistance and reliability, which in turn will prevent contamination of the water body in the period of coast protection constructions usage

ENVIRONMENTAL MANAGEMENT IN JOINT STREAMS REGULATION BY TWO HYDROELECTRIC COMPLEXES

Lowland river water power developments are usually built to solve complex tasks on the basis of the requirements of rational use of water resources. First of all, operating conditions of hydroelectric complex structures should provide safety and economic efficiency in their work. Besides, they are aimed to satisfy various demands of water consumers. It is particularly important that behaviour of hydroelectric complex structures should satisfy contemporary requirements of environmental security. The most important task here is to create favourable ecological conditions of life for people who live in settlements located in the zone of influence of two hydroelectric complexes located on different rivers. Here, to achieve environmental targets it is necessary to interlink modes of operation of these water storage control structures. There are two water power developments built in the Republic of Bashkortostan, Russia, in the middle flow of the Belaya River. Both of them have considerable impact on the formation of level mode and different consumers’ water supply. They are Umaguzinskiy and Nugushskiy water power developments. Both hydroelectric complexes and their water reservoirs together satisfy the following generally accepted requirements of water consumers: - they prevent the lowering of the water level in the river Belaya (during low streamflow period) below the minimum values required to ensure proper water supply for industrial enterprises; - they generate electric power and provide industries and cities with electricity. To do that each water-economic complex has its own water reservoir and a set of retaining structures and required culvert installations. In addition, the following environmental requirements are imposed on co-regulation of water runoff: - protection of waterfronts of the towns Meleuz, Salavat, Ishimbay and Sterlitamak from flooding in flood season; -protection of the territories of refineries in flood season (during water rise). Umaguzinskiy water power development has the following water sluices to control water stream: 1) submerged flood-discharge outlet; 2) shore flood spillway; 3) aggregates of powerhouse. General water carrying capacity of hydroelectric complex structures is 3915 м3/c. Nugushskiy hydroelectric complex consists of hydraulic engineering structure power room (1) and left shore spillway (2). Combined water carrying capacity of all hydroelectric complex structures here is 1250 м3/c. The authors investigated operation modes of Nugushskiy and Umaguzinskiy water power developments when linked into one water-economic complex and came to the conclusion that modes of operation of these water storage control structures should be adjusted in accordance with the operational condition of the main pressure installations and of downstream flood-control facilities. In particular, it is necessary to take into account the unfinished state of flood prevention measures in the middle reaches of the river Belaya