Distribution of River Water and Suspended Sediment Loads in the
Deltas of Rivers in the Basins of The Laptev and East-Siberian
Seas
V.V. Ivanov and A.A. Piskun
State Research Center - Arctic and Antarctic Research Institute, 38 Bering St., 199226 St. Petersburg, Russia
Received 3 March 1997 and accepted in revised form 3 March 1998
Abstract - The article presents estimates of the annual and seasonal distribution of river
water and suspended sediment load and their variability in complicated fork river deltas of
the Laptev and East-Siberian Seas. The estimates are based on the methodology, which
includes a complex of developed or improved methods for hydraulic-morphometric
parameterization of channels, hydraulic calculations and physical and numerical modeling.
A particular emphasis is given to rivers Lena and Kolyma deltas that belong to different
types according hydrologic regime. In the Lena delta only its lower part is influenced by the
sea. In the Kolyma delta the whole of the water area including the head of the delta
experiences the influence of the sea. The main factor affecting water runoff and sediments
distribution in the Lena delta branches is river runoff. For the Kolyma delta under the
conditions of steady water motion the water content ratios of the main arms remain quite
stable at different combinations of water discharges in the river and background sea level. At
large surge level rises there is a considerable redistribution of water discharges over the delta
area, reverse currents arc observed (negative discharge values). A comparative analysis of
estimates of the water runoff distribution in the Kolyma delta obtained by different methods
shows that hydraulic calculations are sufficient for most applied tasks. Further studies
should be focused on developing methods to calculate sediment transport for assessing the
distribution of pollutants in deltas and their export to the sea.
Introduction
The river runoff is the main factor that governs the hydrological, hydrochemical and
hydrobiological processes occurring in the deltas. It also significantly influences the water
balance, water exchange, ice thermal conditions, formation of structure and chemistry of water
and bottom sediments of sea areas, primarily in the regions of inflow of rivers and large delta
arms.
Distribution of water discharges and levels in the deltas of rivers of the Laptev and EastSiberian Seas depend on the water and channel regime of these deltas (especially on the
character of the runoff distribution within a year) and on the sea regime (primarily on the
background sea ',::vel fluctuations). From this viewpoint the deltas of large rivers of the seas
mentioned, can be divided into two groups. The deltas where the sea influence extends over the
entire delta, including its head, i.e. the water runoff and levels distribution depends on the sea
regime, belong to the first group. These are the Kolyma and Olenek rivers. The second group
includes the deltas whose water and channel regime depend on the sea influence only in the
lower reaches. These are the Lena and Yana and Indigirka rivers which are subjected to
backwater from the sea only during the short catastrophic surges. For all indicated deltas the
influence of tides on the redistribution of water and sediment load discharges is insignificant
(Ivanov, 1970). The mouths of the Khatanga and Anabar Rivers do not have developed deltas
and are not considered here.
The regime of deltas of the first group and of the lower reaches of the arms of deltas of the
second type, situated in the sea influence zone, depends on the seasonal variations of the runoff
[n: Kassens, H., H.A. Bauch, l. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, 1. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin, 1999.239-250.
Deltas of Rivers in the Basins of The Laptev and East-Siberian
Seas
V.V. Ivanov and A.A. Piskun
State Research Center - Arctic and Antarctic Research Institute, 38 Bering St., 199226 St. Petersburg, Russia
Received 3 March 1997 and accepted in revised form 3 March 1998
Abstract - The article presents estimates of the annual and seasonal distribution of river
water and suspended sediment load and their variability in complicated fork river deltas of
the Laptev and East-Siberian Seas. The estimates are based on the methodology, which
includes a complex of developed or improved methods for hydraulic-morphometric
parameterization of channels, hydraulic calculations and physical and numerical modeling.
A particular emphasis is given to rivers Lena and Kolyma deltas that belong to different
types according hydrologic regime. In the Lena delta only its lower part is influenced by the
sea. In the Kolyma delta the whole of the water area including the head of the delta
experiences the influence of the sea. The main factor affecting water runoff and sediments
distribution in the Lena delta branches is river runoff. For the Kolyma delta under the
conditions of steady water motion the water content ratios of the main arms remain quite
stable at different combinations of water discharges in the river and background sea level. At
large surge level rises there is a considerable redistribution of water discharges over the delta
area, reverse currents arc observed (negative discharge values). A comparative analysis of
estimates of the water runoff distribution in the Kolyma delta obtained by different methods
shows that hydraulic calculations are sufficient for most applied tasks. Further studies
should be focused on developing methods to calculate sediment transport for assessing the
distribution of pollutants in deltas and their export to the sea.
Introduction
The river runoff is the main factor that governs the hydrological, hydrochemical and
hydrobiological processes occurring in the deltas. It also significantly influences the water
balance, water exchange, ice thermal conditions, formation of structure and chemistry of water
and bottom sediments of sea areas, primarily in the regions of inflow of rivers and large delta
arms.
Distribution of water discharges and levels in the deltas of rivers of the Laptev and EastSiberian Seas depend on the water and channel regime of these deltas (especially on the
character of the runoff distribution within a year) and on the sea regime (primarily on the
background sea ',::vel fluctuations). From this viewpoint the deltas of large rivers of the seas
mentioned, can be divided into two groups. The deltas where the sea influence extends over the
entire delta, including its head, i.e. the water runoff and levels distribution depends on the sea
regime, belong to the first group. These are the Kolyma and Olenek rivers. The second group
includes the deltas whose water and channel regime depend on the sea influence only in the
lower reaches. These are the Lena and Yana and Indigirka rivers which are subjected to
backwater from the sea only during the short catastrophic surges. For all indicated deltas the
influence of tides on the redistribution of water and sediment load discharges is insignificant
(Ivanov, 1970). The mouths of the Khatanga and Anabar Rivers do not have developed deltas
and are not considered here.
The regime of deltas of the first group and of the lower reaches of the arms of deltas of the
second type, situated in the sea influence zone, depends on the seasonal variations of the runoff
[n: Kassens, H., H.A. Bauch, l. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, 1. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin, 1999.239-250.