RESEARCH FOR

REGULATED STREAMS REHABILITATION
USING BIOENGINEERING METHODS
order to allow the required permeability and facilitate
works of maintenance and cleaning. With the help
of this method rehabilitation of meandering of the
straightened streams is possible, by using both energy
of the current, and plants, growing on the slopes.
By using this method large plants which grow
on the slopes overgrow smaller plants. Thus, the
streamway remains clean and better permeability of
the streamway is reached. A streamway starts selfformation,
human beings only have to observe that
significant deformations would not occur. In such a
way the volume of maintenance works is reduced.
However, by using this method a danger for drainage
mouth occurs, because it may be plugged by roots of
trees and shrubbery. For this reason in such stretches
it is necessary to change drainage mouths to nonperforated
plastic pipes. This method may be widely
used under Lithuanian conditions, because this does
not require huge investments, and only constant
supervision of the straightened streams is needed.
Meanwhile, renaturalization – an artificial
rehabilitation of the straightened streams which are
close to conditions of natural environment is applied.
In this case morphological properties which are
close to natural ones are being created artificially:
bends are formed and banks are reinforced by natural
and artificial means. Thus, favourable conditions
for settlement of animals and plants, returning to
streamways in the most possible natural condition
are created. Two methods of artificial rehabilitation
(renaturalization) of streamways of the straightened
rivers are distinguished, i.e. partial and full
rehabilitation of streamway.
Figure 3. Longinoja stream (Jormola, 2006).
Partial rehabilitation of streamway is a
rehabilitation of streamway, by using bioengineering
methods and energy of the current (Figure 3).
When using the method of partial rehabilitation of
Antanas Maziliauskas,
Raimundas Baublys, Ramūnas Gegužis
streamway, the streamway is being restored by using
various bioengineering methods, - wicker fences,
stones, fascines and other. By using bioengineering
methods in the regulated streamway, conditions
necessary for development of natural variety are
formed. With a help of this method human beings
allow closer direction formation of the streamway
under natural conditions. When using this method,
the target goals are faster achieved, compared to the
use of aforementioned methods. However, the use
of this method requires investments, i.e. much assets
and work costs demanding method. This method is
broadly used in Western European countries; thus by
using experience of other countries, this method of
renaturalization may be used in Lithuania in full.
Figure 4. River Skerne, (River..., 1998).
Full rehabilitation of streamway is a method when
bends, coves and elements of natural streamway,
necessary for increase of natural variety (Figure 4)
are formed by artificial means. Full rehabilitation
of the streamway is performed by fully reforming
streamway, when bends, coves are established by
using the aforementioned bioengineering methods.
A newly formed streamway with bends, coves and
islands establishes especially favourable conditions
for development of water plants and animals. These
conditions are very close to the natural condition of
the river before its straightening. This is one of the
most effective means of achieving the desired goals
faster. As hydrological and hydraulic conditions
have changed in the artificially formed habitats, both
animals and plants settle in quite soon.
The recent method is quite expensive, demanding
much assets and high work costs, though currently
it has gained popularity in projects of river
rehabilitation in various countries of the world:
Australia, the USA, Great Britain, Netherlands, Finland
as well as in other countries (Conservation…, 2007;
Jormola, 2006, 2008; Living…, 2006; Longinojan…,
112 ReseaRch foR RuRal Development 2012