S.D.ISAYEVA
Some ecological and ethical problems caused by LAND RECLAMATION
Land
reclamation is a powerful factor of the human impact on environment in Russia.
Some ecological and ethical problems caused by land reclamation are arising in
different regions. These problems deal with water table rise, damage to the
water resources, salinization, bogging etc. For a long time they were not so
important because the main aim was the yield receiving. Nowadays as the result
we have unfavorable ecological situation on irrigation land in Volga basin as
well as in other basins. Very often ecological crises are connected with
economic and social crises.
Practice shows
that rough forms of regulation of natural medium (the big irrigation and drainage
systems, cascades of the water storage etc.) are often antagonistic to
tendencies of natural systems evolution. In such cases the reclamation methods
are ineffective. Irrigation and drainage systems destroy and agriculture lands
would be deteriorated.
So there is a
problem of how to regulate human impact on natural geological systems
(geosystems) and this problem must be solved. Analysis of the ecological risk
serves as a basis of land reclamation and hydrotechnic designs are oriented to
increase an adequacy of the designed measures with natural conditions.
For
agricultural success and effective development of water and land resources the
appropriate relation must be found between the designed man-made influence and
the potential sustainability and stability of geosystem conditions.
The ecological
stability of a geosystem is understood as the possibility to resist against
various fluctuations (both natural and anthropogenic) for a determined period
and also as the possibility to guard the structural and functional unity that
would be favorable to the man.
Ecological risk
is a probability of some losses resulting from the ecologically unfavorable
processes or disorders caused by the land reclamation or by water-building
practice.
In case of a synchronized development of
several unfavorable processes occurring in boundaries of a geosystem the risk
calculation takes into account that they all will take part in deteriorating
the area, i.e. it will be equal to the sum of risks of each unfavorable process
(soil, hydrogeological, engineering-geologic etc.) for all geosystem components
and risks, initiated by rejections of technical systems and structures. We use
data of actual observation or polyvariant simulation of hydraulic engineering
measures etc.
The allowable
risk is determined under the condition of preserving the geosystem index in the
field of sustainable states.
The geosystem
stability to the impact of both land reclamation and hydraulic engineering
measures must be estimated on the base of comparing alternative designs of the
proper impact and agricultural activities.
The estimation
of geosystems ecological stability should be based on the natural and genetic
approach taking into consideration ecological and ethical problems.
Mathematical simulation of various types of loads of land reclamation and
hydraulic engineering is used and probability for designed variants is
computed.
Probabilities
of system escaping beyond allowable limits have to be predicted for various
loads. These variants of stability destruction risks for the geosystem as well
as the probable size of ecological, social and economic damages must be
estimated. Predicted results should be followed by suggesting measures for
increasing stability in the agricultural production and also by determining
reasonable limitations for impacts of both water building and land reclamation.
Ecological stability of the region development should be ensured.
The problem of
regulating human impact on geosystem is being solved. A strategy should be
determined which would allow accomplishing a designed aim without any
destruction of development process of natural system caused by human activity.
For realizing
the mathematical model the simulation is used in a complex with probabilistic
methods allowing - together with estimations of the consulting experts - to
choose the optimum strategy. Recommending rational influences on natural
systems must follow the choice of an allowable variant - based on problem
solution and expert estimations -.
In the course
of realizing recommendations for regulating the influence the risk analyses
complex includes:
-
control of conditions for a
geosystem
-
complex estimating (for every
geosystem component) the prediction reliability
-
continual estimation of
geosystem conditions
-
realization of corrections for
predicted conditions based on risk analyses methodology (after receiving
results of system diagnostic and estimating the prediction reliability)
-
determining the regulation
influences for regime function ensuring stability of the ecologically favorable
geosystem.