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M. Habel et al.
and older terraces. Another factor favouring the abstraction of river channel sediments
is the reclamation of sediment, associated with periodic replenishment during floods
[38], or in the case of the lower Vistula, excessive sediment accumulation caused
by local hydromorphological conditions of the channel or hydrotechnical buildings
[40, 41].
The material, transported by rivers in the form of clastic debris, originates mainly
from mass movements, soil erosion, as well as from the erosion of the riverbed and the
riverbanks itself [8]. Nowadays, cities are becoming more and more important in the
supply of clastic material to riverbeds. They are an efficient source of anthropogenic
material coming from many times larger surfaces than in natural conditions [42]. An
important source of direct supply of clastic material for fluvial transport, under natural
conditions, is a riverbed with variable bottom and intensively eroded riverbanks.
The supply of clastic material transported also in the form of a suspended material
increases many times when, under conditions of training of the channel (a regulated
riverbed with river grones), it quickly deepens its bottom [36, 39, 43–48].
Currently, the rehabilitation of degraded and changed aquatic ecosystems has
become an integral part of the river basin and river sediment management. For
this reason, various sediment management projects have been initiated or fulfil in
few countries [49]. Some examples include creation of lateral channels along the
Rhine River [50], reconnecting the Danube old-arm system to the main channel
[51], modernization and demolished of river groines to renew sediment dynamics
in the Mur River [52], artificial replenishment of sediments the Ain River [53], and
removing dams in US [36] to re-establish the river continuum. Sand and gravel are
artificially replenishment to reinforce available spawning sediment supply below
dams on a minimum of 13 rivers in California (Sacramento, Merced, Tuolumne,
Mokelumne, Stanislaus, Russian, Dry, San Juan, San Luis Rey, Cache, Dry, Stony,
and Tujunga Wash Rivers) [54]. The need for completing such hydrotechnical works
arises from the necessity to implement the wants introduced by the WFD consisting
within the implementation of procedures ensuring the minimization of negative
impact of hydrotechnical structures oriented towards control and good conditions
of surface waters and related aquatic ecosystems. One among the procedures recommended for the development of dam reservoirs requests maintaining the continuum
of sediment transport or sediment replacement of the river downstream the dam. The
term river sediment replenishment denotes the implementation of varied technical
solutions that ensure constant replenishment of river load deficiency within the reach
downstream of the dam, adapt to the sort of river competence and therefore the sort
of flow operation by the dam. Such solutions include pumping systems, which move
river sediments from the backwater zone of the reservoir to the reach below the dam,
or directly shifting sediments downstream the reservoir by means of water transport
e.g. employing a barge on plain rivers or carriage e.g. transport of gravel on mountain
rivers. In western Europe and U.S. actions are undertaken to replenish the deficit of
river sediments by employing point delivery of sediment material to the riverbed
(Fig. 12.1), often directly below the dams [39, 55, 56]. The Ameri-cans, however,
were the primary introducing this solution within the 90s, river sediment replenishing
was already being conducted on 13 fragments of the Sacramento River in California
M. Habel et al.
and older terraces. Another factor favouring the abstraction of river channel sediments
is the reclamation of sediment, associated with periodic replenishment during floods
[38], or in the case of the lower Vistula, excessive sediment accumulation caused
by local hydromorphological conditions of the channel or hydrotechnical buildings
[40, 41].
The material, transported by rivers in the form of clastic debris, originates mainly
from mass movements, soil erosion, as well as from the erosion of the riverbed and the
riverbanks itself [8]. Nowadays, cities are becoming more and more important in the
supply of clastic material to riverbeds. They are an efficient source of anthropogenic
material coming from many times larger surfaces than in natural conditions [42]. An
important source of direct supply of clastic material for fluvial transport, under natural
conditions, is a riverbed with variable bottom and intensively eroded riverbanks.
The supply of clastic material transported also in the form of a suspended material
increases many times when, under conditions of training of the channel (a regulated
riverbed with river grones), it quickly deepens its bottom [36, 39, 43–48].
Currently, the rehabilitation of degraded and changed aquatic ecosystems has
become an integral part of the river basin and river sediment management. For
this reason, various sediment management projects have been initiated or fulfil in
few countries [49]. Some examples include creation of lateral channels along the
Rhine River [50], reconnecting the Danube old-arm system to the main channel
[51], modernization and demolished of river groines to renew sediment dynamics
in the Mur River [52], artificial replenishment of sediments the Ain River [53], and
removing dams in US [36] to re-establish the river continuum. Sand and gravel are
artificially replenishment to reinforce available spawning sediment supply below
dams on a minimum of 13 rivers in California (Sacramento, Merced, Tuolumne,
Mokelumne, Stanislaus, Russian, Dry, San Juan, San Luis Rey, Cache, Dry, Stony,
and Tujunga Wash Rivers) [54]. The need for completing such hydrotechnical works
arises from the necessity to implement the wants introduced by the WFD consisting
within the implementation of procedures ensuring the minimization of negative
impact of hydrotechnical structures oriented towards control and good conditions
of surface waters and related aquatic ecosystems. One among the procedures recommended for the development of dam reservoirs requests maintaining the continuum
of sediment transport or sediment replacement of the river downstream the dam. The
term river sediment replenishment denotes the implementation of varied technical
solutions that ensure constant replenishment of river load deficiency within the reach
downstream of the dam, adapt to the sort of river competence and therefore the sort
of flow operation by the dam. Such solutions include pumping systems, which move
river sediments from the backwater zone of the reservoir to the reach below the dam,
or directly shifting sediments downstream the reservoir by means of water transport
e.g. employing a barge on plain rivers or carriage e.g. transport of gravel on mountain
rivers. In western Europe and U.S. actions are undertaken to replenish the deficit of
river sediments by employing point delivery of sediment material to the riverbed
(Fig. 12.1), often directly below the dams [39, 55, 56]. The Ameri-cans, however,
were the primary introducing this solution within the 90s, river sediment replenishing
was already being conducted on 13 fragments of the Sacramento River in California