Erosion runoff increased risk of the residents and the Water quality in the context of the expected climate change

Transcription

1 Department of Irrigation, Drainage and Landscape Engineering Faculty of Civil Engineering Czech Technical University in Prague Czech Republic Erosion runoff increased risk of the residents and the Water quality in the context of the expected climate change (study for territory of the Czech Republic) Tomáš Dostál, Josef Krása, Miroslav Bauer, Luděk Strouhal, Barbora Jáchymová, Jan Devátý, Pavel Rosendrof

2 INTRODUCTION Floods hydrological forecast (especially large ones) Flash floods stochastic, forecast only meteorological Pluvial floods (sheet and concentrated surface runoff from the fields) nearly impossible to forecast The only effective control of damages = prevention Necessary to identify localities, where pluvial floods can threaten: infrastructure = urban areas, transportation water sources

3 Therefore the project was opened and financed by Ministry of Interior of the CR, to determine: Interactive map of the Czech Republic with marked critical points public free WWW application - points of collision of pluvial floods and infrastructure, residents and water sources Simple assessment of effectiveness of control measures The effect of expected climate change

4 The analyses cover ca km 2, area split into 120 subcatchments Raster analysis in resolution 10x10 m, based on maps 1: and higher Totally ca potentially critical points for further analysis

5 METHODOLOGY Identification of surface runoff trajectories DEM treated to avoid pits Flow accumulation assumptions: Source area for accumulated surface flow over 1 ha included land-use and soil parameters Interrupted by: - water course of 2nd order Strahler (standard water course = not pluvial flood) - water body (reservoir) Two steps: Hydrological evaluation using ARC INFO flow analysis Sediment transport soil loss and sediment transport using model WATEM/SEDEM fully distributed, USLE based approach, including sediment transport, based on distributed transport capacity assessment

6 critical points are then classified using model WATEM/SEDEM into 5 categories, according to their THREAT: Source area (area of subbasin) Total soil loss in the source area Total sediment transport through critical point (buffer)

7 Flow accumulation critical points determination

8 Calculation of erosion x deposition gives information about spatial distribution of soil loss and deposition within the subcatchment

9 Calculation of total inflow gives an information about amount of sediment, transported into/through urban areas classification of THREAT

10 Final evaluation risk analysis: Infrastructure classified into three classes according to its vulnerability Vulnerability 5 categories of threat (critical points) 3 categories of vulnerability (types of structures) Risk where vulnerable structures meets with threat of intensive runoff and sediment transport risk matrice Threat Vulnerability Risk

11 Vulnerability - trajectory Z tot n i 1 1 l p i KZ i Z tot total vulnerability KZ i partial vulnerability L i - distance from beginning of urban area p index of distance

12 Classification of vulnerability according to database of basic map objects of the CR 1: (basic topological source) Category of structures Type of structure Category structures and buildings greenhouse 1 structures and buildings dump 1 structures and buildings cemetery 1 communications path 1 communications track 1 communications parking place 1 vegetation orchard 1 vegetation garden 1 structures and buildings other surfaces in urban areas 2 structures and buildings sediment trap pond 2 communications street 2 communications local railroad 2 communications rail yard 2 communications airport 2 communications local road 2 structures and buildings block of buildings 3 communications speed road 3 communications rail road 3 communications rail station 3 networks power plant 3 networks pumping station of product pipe 3

13 The effect of climate change was taken into account Simulated by change in: - rainfall erosivity R factor change - crop rotation C factor change Sorry, no time for detailed description of procedures. Four scenarios of control measures were simulated Application of: Crop changes Technology changes Grassing Technical measures on the level of individual parcel Sorry, no time for detailed description of procedures.

14 Comparison of critical points in individual categories assuming climate change

15 General increase of critical points of category 4 and 5 due to expected climate changes

16 www application map presentation with all results: ex.php Public free for land-users, decision makers, farmers, local governments,. In Czech language but can be used with automatic Google translation

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20 THANK YOU FOR YOUR ATTENTION AND HAVE A NICE DAY dostal@fsv.cvut.cz The presentation has been supported by project No. VG and QJ