E. N. Dolgopolova

The conditions for tidal bore formation and its effect on the transport of saline water at river mouths

Approaches to the mathematical description of bore propagation upstream a river in its mouth area are briefly reviewed. Data on some river mouths, where bores were observed, are given, and the conditions of their formation are considered. The existence of a bore is determined by tide magnitude, river runoff, and the depth profile in the estuary. The same factors govern seawater penetration distance into river mouths, the degree of mixing of seawater and river water, and the regularities of sediment motion at river mouths. The types of water circulation at the mouths of the greatest rivers, where bore takes place, are considered, and its effect on seawater intrusion range into river mouths is analyzed. The results of comparison of the effect of channel training on bore existence conditions and the propagation range of saline water into the estuaries of the Seine (France) and Qiantang (China) are given.

Water and sediment dynamics at Saint Lawrence River mouth

The main features of the hydrological regime and morphological structure of the estuarine-type mouth area of the Saint Lawrence River are considered. Data on the structure of water masses, thermal and ice regimes in the Gulf of Saint Lawrence, which has a significant effect on the estuary, are given. The major attention is paid to water mixing processes, water and sediment dynamics in the estuary under the joint effect of river runoff and tides, and as a function of bed topography. The parameter determining the type of water stratification and circulation is discussed. The effect of the Coriolis force on the stratified flow in the estuary and formation of the geostrophic current is discussed.

Classification of estuaries by hydrodynamic processes

Various characteristics determining the estuary and factors affecting the formation of its hydrological regime are considered. The results of studying the interaction between sea and river waters in estuaries and the characteristic features of suspended sediment transport under the competing effect of river runoff and tides are given. Possible approaches to the classification of estuaries, proposed by different authors, are discussed.

Sediment transport and saltwater intrusion into the weakly stratified estuary of the Delaware R.

Data on the hydrological regime and morphological structure of the estuarine-type mouth area of the Delaware R. are presented. The specific features of fresh and salt water interaction in different parts of the estuary are considered. The attention is focused on water mixing processes and water and sediment dynamics in the estuary under the joint effect of river runoff and tides. The parameter that governs the type of water circulation and stratification in the estuary is evaluated. Correlation between variations in water salinity and turbidity along the estuary is analyzed. Estimates of sediment balance components in the Delaware R. estuary are given.

Vertical transfer coefficient in natural streams

Turbulent vertical transfer in natural open and under-ice channel flows is considered. Methods for the assessment of turbulent viscosity in the core and shift layers of under-ice flow are proposed and checked. A method is developed for the calculation of the vertical distribution of turbulent exchange coefficient in an underice flow given the mean flow characteristics.

Mathematical modeling of the formation and progradation of a river mouth bar into a sea: Case study of Danube Delta branches

The effect of sediment yield of a stream and the energy of sea waves on the formation of bars and their dynamics at nontidal river mouths is demonstrated. Data on variations in the hydrological regime of the Potapovskii and Bystryi branches in the Danube Delta and the morphodynamics of their bars are given. Major problems of mathematical modeling of the formation and progradation of mouth bars into the sea are discussed. An analytical expression is obtained for the shape of the foreset slope of a bar, which moves over a constant-slope seabed. The results of simulation were checked against data on the Potapovskii and Bystryi branches in the Danube Delta.

Interaction between Streams and Lower Surfaces of Ice Cover

The structure of the boundary layer is studied at the lower ice surface in Lake Baikal and the Moskva River. The Rossby parameter is used to compare the roughness of the lower ice surfaces in these water bodies. An attempt is made to estimate the thickness of the boundary layers under study.

Regularities in the motion of water and sediments at the mouth of a river of estuarine-deltaic type: Case study of the Yenisei R.

The main regularities of the motion of water and sediment at the mouths of different types are described. Examples of river mouths of those types are given. The principles of modern classification of river mouths, which takes into account the hydrological processes in mouth zones, are used for zoning the mouth area of the Yenisei R. The main regularities in the interaction of sea and river waters and sediment transport, typical of estuarine-deltaic mouth type, are considered. The parameters that determine the type of water circulation and stratification in an estuary are evaluated. The main attention is paid to studying the mixing of river and sea water at the estuarine-deltaic mouth of the Yenisei and the mechanism of sediment motion at the mouth in the presence of delta under the joint effect of river runoff and tides.

On the Interaction between Flow and Erodible Bed

The structure of flow moving near solid and moving boundaries is considered. Experimental data are presented to demonstrate that sand ridge can form as a result of interaction between the flow and the boundary.

Energy Characteristics of the Transient Flow Effect on Channel and Bank Deformations and the Formation of Flow Secondary Pollution from Bottom Sediments

The ratio of the energy of water release into the lower pool of a waterworks facility for the time of release to the energy generated by the long-wave component of the wave spectrum caused by the release is considered. The effect of long-wave components of the wave spectrum on the channel and shore deformations is evaluated. An empirical relationship is proposed to describe the dependence of flow velocity on the release characteristics. Analysis of exchange processes between the flow and bottom deposits along with the obtained relationships is used to assess possible pollutant release from bottom deposits into water.