FLOOD PROTECTION MEASURES OF
THE SLOVAK REPUBLIC
Ing. Peter Čadek, PhD.
The Slovak Water Management
Enterprise
• existing flood risk – occurrence of 3rd degree of flood
awareness according national the Flood protection Act
• potential occurrence of flood risks - set of potential non-
dimensional aggregated value represent natural potential of
maximal discharges occurrences and circumstance to
creation of floods divided to:
– regional potential characterised floods of lowlands and
alluviums
– local potential characterised of flesh floods
• impact of floods represented by the element of risks: human
health, cultural heritage, environment and economy activities
Selection / evaluation and weigting
criteria of areas with potential
significant flood risk
Factorial relative values of significance
of flood risk and potential of flood risks
• the percentage of days with the proven existence of flood risk
in relation to the overall reference period
• the categorization of a significant probable occurrence of
flood risk, expressed by relevant classes of local potential
and regional potential
Types of flood protection measures
measures to reduce (decelerate) run-off from river basin into the
water courses, to increase retention capability of river basin or to
support natural accumulation of water in the suitable areas –
measures at agricultural soils, in forests and urban areas
measures which reduce flood peak discharge – construction,
maintenance, repair or reconstruction of water structures or polders
measures which protect land from inundated water of water
courses – technical river training works, flood protection dykes,
walls, other linear flood protection structures
measures which protect land from inundated „inner waters“ –
installations (equipment) for pumping the „inner waters“
measures to ensure adequate flow capacity of the channels of
water courses – maintenance of river channels and their
vegetation, removal of deposits
Proposed climate change adaptation measures in the field of water management
PROPOSED MEASURES
IN STRATEGIC DOCUMENT
measures which decelerate runoff
from watersheds
measures which improve economy of
water management
measures which reduce
peak discharge of floods
measures focused at prevention of
water contamination
measures to protect land from inundated
waters of water courses
measures focused at improvement of
waste water treatment
measures focused at improvement
of river channels capacitymeasures focused at risk assessment
measures which increase actively controlled
volume of runoff from the territorymeasures in the research field
measures in the field of spatial planning
Distributed rainfall-runoff modelling1. ISSOP model / GIS application
developed by ESPRIT, Inc.2. Deterministic, physically based
model3. From WETSPA derived model
podpovrchový
odtok
podzemný
odtok
povrchový odtok Zrážky
Infiltrácia
Kapilárny
výstup
Evapotranspirácia
Priesak
Podpovrchový
odtok
Podzemný odtok
PÔDA
Povrchový odtok
NASÝTENÁ
ZÓNA
POVRCH
ATMO-
SFÉRA
Slnečné
žiarenie
ácia
Critical flood waves designingThesis: 100-year flood wave is affected
by 100-rainfall1. Runoff designed waves calculations2. Current landcover/landuse scenario3. Extreme forestation scenario4. Landcover/landuse optimizing
scenario
Assessment of possible impacts of current & proposed measures in catchments to achieve goals
Landscape data inputs1. Gridded DEM in 10 x 10 m resolution2. Soil types3. Landcover/Landuse4. Stream network& Many derived synthetic layers
Estimation of designed rainfall1. N-year maximum daily rainfalls map2. Rainfall event duration equals to
catchment time of concetration3. In time-equal rainfall intensity
Extreme landcover / landusechange1. Keep urbanized & industrial
areas unchanged2. Afforestation of other LCLU
with potential naturalvegetation
Current landcover / landuse
Optimal landcover / landuse change1. Keep urbanized & industrial areas
unchanged2. Landcover / landuse types change
of areas with runoff coefficienthigher 60 %
3. Arable lands change to pasturesor grasslands
4. Other landcover / landuse typeschange to forest by potentialnatural vegetation
Mean change: – 4.85 %Category with highest mean
change:
Catchments up to 2 km²
– 9.5 %But huge range: - 40 % - 0 %
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Pe
rcen
tual
chan
ge f
rom
pe
akd
isch
arge
Area [km²]
Determination Between Catchment Area & Effectiveness
-45
-35
-25
-15
-50 50 100 150 200 250 300 350 400 450 500
Focused on catchments up to 500 km² areaAverage evaluated area: 422 km²
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
up
to
2 k
m²
up
to
5 k
m²
up
to
10
km
²
up
to
50
km
²
up
to
10
0 k
m²
up
to
25
0 k
m²
up
to
50
0 k
m²
up
to
10
00
km
²
up
to
25
00
km
²
up
to
50
00
km
²
Pe
rce
ntu
al c
han
ge
Mean percentual change from peak discharge by area categories
Thank you for you attention