In recent years artificial beaches are often used for coastal protection of seas and man-made lakes. Volume of nourishment depends on the shape and the length of the equilibrium beach profile. When solving a wide range of tasks different methods for equilibrium beach profile calculation are used. In this paper we make an attempt of reliability assessment of some methods currently used for calculation. We compared the natural beach profile with equilibrium beach profile calculated by different methods. Three approaches were used to calculate the shape of equilibrium beach profile: the Bruun-Dean formula, the method prescribed by Coastal Structure Construction Code, and numerical modeling by SBEACH. To obtain the source information an artificial beach at the Novosibirsk Reservoir, Russia, was chosen. This beach was constructed in 1959-1962, and replenished 25 years later. The morphometric characteristics of the beach are still almost unchanged. This allowed us to conclude that the beach profile is in equilibrium. The analysis shows that the equilibrium profile calculated by Dean’s formula gives the best agreement with the data. That is of theoretical and practice interest. It should be noted the method originally developed for the ocean coasts works well at man-made lakes. The work was supported by RFBR (projects 11-05-00615-а and 11-05-10046-к) and federal target program “Research and development on priority directions of scientific-technological complex of Russia in 2007-2013”(project 16.515.11.5075).

On the Olkhon Island we distinguished three genetic types of the shores: structural-abrasion, abrasion and accumulative ones. According to the dominating exogenous process these types were subdivided into abrasionlandslide, abrasion-fall; abrasion-aeolian and biogenic subtypes. Quantitative measurements of the shore length showed that the total shore length of the Olkhon Island including lake-like lagoons constitutes 225 km. Of the total length abrasion shores consist the 68% (153 km), structural-abrasion shores – 25.3% (57 km), and accumulative ones – 6.7% (15 km).

The coastal dynamics of the Curonian Spit, a large accretive landform with its eroded root, is discussed. For this area, the new data on the coastal development for the last 100 years were obtained; the characteristic of current coastal state was given; mathematical simulation of the coastal processes for assessment of the sediment deficit in the near shore zone was made. Evanescence of the sediment deficit phenomenon in the area under study is demonstrated. Here, even during rather short periods of the deficit increase, the development of wave-induced destructive processes is observed; therefore three major ways to mitigate the risk of coastal erosion (i.e. the construction of impenetrable or penetrable groins, a detached breakwater and an artificial beach) are considered, including the peculiarities of the spit shores development as a result of coastal protection activities.

On the Olkhon Island we distinguished three genetic types of the shores: structural-abrasion, abrasion and accumulative ones. According to the dominating exogenous process these types were subdivided into abrasionlandslide, abrasion-fall; abrasion-aeolian and biogenic subtypes. Quantitative measurements of the shore length showed that the total shore length of the Olkhon Island including lake-like lagoons constitutes 225 km. Of the total length abrasion shores consist the 68% (153 km), structural-abrasion shores – 25.3% (57 km), and accumulative ones – 6.7% (15 km).

Erosion and abrasion play the main role in the relief formation and sedimentation in the basin of Novosibirsk Reservoir. These processes caused important changes of morphometric characteristics of the basin. For instance, the average thickness of accreted sediments has reached 0.94 m, the Reservoir total capacity has reduced by 1.02 km 3 , its average and maximum depth and water area have diminished notably, but average and maximum width have increased. The shoreline length, the number and area of island have changed too. The character of these changes is similar to changes in other reservoirs of this type.

The peculiarities of a coastal morphology of large man-made lakes under the wave-dominated, fluvial dominated and transitional environments were discussed. It was shown that the fluvial-dominated environment is similar to the one in a river delta. In the transitional environments, the gradual replacement of delta sub-environments by shallow areas is observed. In the wave-dominated environments the relief is similar to the characteristic relief of the sea coastal zone.

Sedimentary structure in a delta-like area of the man-made lake basin, in the coastal transitional zone of wavedominated and fluvial-dominated environments, and at the coasts with normal development of reservoirs where wind-induced waves are the key driving factor were thoroughly studied and described for the first time.

The peculiarities of a coastal morphology of large man-made lakes under the wave-dominated, fluvial dominated and transitional environments were discussed. It was shown that the fluvial-dominated environment is similar to the one in a river delta. In the transitional environments, the gradual replacement of delta sub-environments by shallow areas is observed. In the wave-dominated environments the relief is similar to the characteristic relief of the sea coastal zone.

In the large reservoirs the classical development of shores under the impact of wave action and water level fluctuations results in erosion during the water level rise and in the movement of coastline toward water storage during fall in water level. In the case of “non-classical” development water level rise results in the submergence of coastal areas and accumulation, while the fall in the water level results in the cutting of the dereliction, slackening of the beach drift and subsequent cutting of the adjacent shores. Such types of evolution take place on the shores of both large reservoirs and seas. Considering geomorphological similarity of the coasts of seas and the storage lakes, large reservoirs may serve as models for studying and forecasting seashore response to water level fluctuations.