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 Zvolen, 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

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 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” Forest influence – forest function Antropogenic activities utilizing of forest functions

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).

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 1-10 mm Herbal cover and litter layer 5 – 20 mm Forest soil30 – 40 mm (400) TOTAL36 – 70 mm

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

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 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 A separate chapter is :

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

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