Hydric functions and
their utilization
Zvolen, 2.4. 2014
Development of basic
concepts for using of
forest effect on
watershed`s hydrology in
terms of flood prevention,
including using of
communities of tree
species growing outside
the forest
prof. Ing. Vladimír Čaboun, CSc.
Ing. Jozef Capuliak, PhD.
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric functions
and their utilization
Hydric functions of forests belong to the best known
and most important functions. It means the influence
of forest on the water in its widest meaning of the
word. Interactions among forest, water and other
components of the environment vary widely . Forest is
only one factor of water cycle in the landscape, so its
impact on the water regime is different in different
conditions.
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric functions and
their utilization
More than 100 years of research
confirmed that the forests provide:
 extraordinary ability to retain rainfall water in
runoff (retention function)
 accumulate rainfall water over large surface of
trees, in litter and in soil (accumulation function)
slowing down outflow of water by
transformation of surface runoff to underground
drainage (retardation function)
 The ability to control the amount of run-off
water in surface streams (regulatory function)
Ability to influence the quality and hygiene of
available water, cleanness of streams and rivers
and silting of water reservoirs
Ability to influence the quality, quantity,
movement and speed of snow melting
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Ecosystem approach to
forest and other
communities of tree
species in the landscape,
their functions and
possibilities of functions
utilization in economic
and social fields
Antropogenic activities utilizing of forest functions
Forest influence –
forest function
Specified sorting of forest function
forms an essential information
base for the use of a function of
trees and their communities in the
landscape by human society. Due
to the market mechanism is
therefore necessary to create the
widest range of possibilities for
using the functions of trees and
their communities and gradually
create the legislative proposals for
solving the financial consideration
for the use of forest functions in
the economic and social spheres.
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Water balance
Water balance in forest ecosystems illustrate the
correlation between income component of water
(atmospheric precipitation) and out come
components of water (evapotranspiration, runoff
into surface and ground water).
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Evapotranspiration
Evapotranspiration of forest ecosystems
depends on:
 except for climatic conditions also on habitat of
vegetation cover and its properties, as evaporation from
vegetation (transpiration) is determined not only by
physical laws, as well as anatomical, morphological and
physiological properties of plants.
size of surface, which could be damped
 the intensity of rainfall, temperature, humidity and air
movement
 the total rainfall
the occurrence of horizontal precipitation
 the species, age and spatial structure of vegetation, the
degree of impairment, disability tree species and entire
forest stand
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Water interception
Sprinkle losses - water retention by wetting
the surface of tree species depends on:
size of surface, which could be damped
 intensity of precipitation
 total rainfall
 occurrence of horizontal precipitation
 species, age and spatial structure of vegetation
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Water infiltration
Infiltration of rainwater in the soil is closely
related to the state of the overlying layer of
humus. If forest management disrupt this
layer, immediately it rapidly increase
surface runoff and erosion, what caused
fluctuating of flow rate in catchment
The process of
infiltration is influenced
by the intensity and the
duration of rainfall and
the character of the
soil, especially partcle
size composition and
initial soil moisture
condition of the soil.
The wetter the soil, the
less water permeability.
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric functions and
their utilization
Impact of forest on runoff during melting
of the snow
In areas with large snowfalls forests have an important
function in reducing peaks of spring flood outflow rate
and extending the outflow for a longer period of time.
Forest prevents the rapid melting of snow. While from
the meadows flew in one day from 5.8 to 11.8 mm owing to the exposure slope, from spruce forest flew
5.0 mm and from beech forest 4.3 mm of water from
melting snow, regardless of exposure slope.
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric functions and
their utilization
Impact of forest cover on runoff water
during flood waves
Forests, although not completely prevent flood waves,
but can significantly mitigate their progress.
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Retention capacity
Total retention = retention capacity of forest
stands for short-term heavy rainfall may reach
up to 70 mm. This value applies to state of the
100% forest cover in the landscape and the
stand density of 1.0 (or 100% canopy). However
the part of forest includes treeless areas ( the
deforested area) which decrease the retention
capacity of the landscape. At first slowly, up to
50-60% forest cover , then - below this threshold,
is a decrease of retention more significant.
Retention capacity of forest ecosystems
Canopy of forest stand
Herbal cover and litter layer
Forest soil
TOTAL
1-10 mm
5 – 20 mm
30 – 40 mm
(400)
36 – 70 mm
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Retention capacity
Retention capacity of forest ecosystems
 If the soil is completely saturated , rainfall´s
water outflows and it creates the most dangerous
flow for creating floods .
 Soil as a water reservoir has amazing potential
and can retain up to 400 mm of water . In our
natural conditions , the forest soil is always
partially saturated.
 In extreme rainfall in a short period of time with
intensity of 100 mm retained forests 68 mm water
and grassland only 46 mm of water, or about 67 %
of the amount of water
retained by forest.
Significantly poorer
retention capacity of
water has arable land in
the period without
vegetation cover
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric functions and
their utilization
Determinants of resulting runof and its
temporal changes include:
 geomorphological characteristics of
topography ( slope, embossed topography, etc.),
 hydrogeological structure of catchment
(nature of permeability rocks, the presence of
aquifers, etc.),
 meteorological conditions ( duration and
intensity of rainfall, interaction of horizontal
precipitation, etc.),
 water balance of forest stands ( interception,
reserve of soil water , the state of forest road network
in relation to surface run-off , etc.),
 total catchment forest cover and structure of
non-forest landscape of catchment
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric funktions and
their utilization
In terms of water management, it is important
to realize that hydric forest functions can
satisfactorily and longly fulfill only healtly
forest, corresponding to a given site
conditions , thus ecologically stable forest
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric functions and
ecological stability
Analysis of ecological-stabilization and
functional effectiveness of forest
ecosystems in the landscape
On the basis of available experimental results there
was carried out primary analysis of the functional
effectiveness of forest ecosystems in the landscape
and the system for its detection and classification was
worked out.
This system follows up the system of the classification
of ecological stability, as long-term ecological stability
is a basic precondition for securing long-term
functionality of forests.
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric functions and
ecological stability
Classification system of total and partial
ecological stability. Basic indicators of ecological
stability in forest ecosystem are:
1. Species structure
2. Age structure
3. Vertical structure
4. Horizontal structure
5. Mosaic structure
6. Regeneration - security of
next development cycle
7. Static stability
8. Morphology and health
condition of trees
1
8
2
7
3
4
6
5
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
Hydric functions and
their utilization
A separate chapter is :
 Impact on water quality and hygiene




Impact on quantity of water in flows
The influence of the source of drinking water
Impact on protection of mineral water sources
The impact on flows, water areas and life in them
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
CONCLUSION
 forest complexes reduced rainfall extremities - reduce
the size of big water runoff and increase the size of small
water runoff.
 In our conditions , forest cover can cause a reduction
in the maximum runoff by up to 50 %.
 In the driest months, the runoff from the forest is 1.43
times higher than runoff from fields and 1.58 times higher
than the outflow of permanent grassland.
 Very important is information that in forestless areas
occurs about 47 % higher culmination of big waters
compared to forested land. By afforestation of forestless
landscape was reduced the culmination of big waters
approximately in 1.5 times.
 Extreme water level in forested catchment, what
occurs likely once every 100 years ( " hundred water" ), it
is possible in compareble deforested catchment
expected every 16 years.
 Forest ecosystems reduce the extremity of weather,
but fulfill also an important role in terms of quality and
quantity of drinking water
HUSKROUA 1101/262 – “HYDROFOR: Systems of optimal forest
management for enhancing the hydrological role of forests in preventing
the floods in Bodrog river catchment”
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