Modeliranje poplavne ogroženosti Poljanske doline s pomočjo orodja HEC-RAS

Bačnar, Katja (author), Natek, Karel (mentor)

S programskim paketom ArcGIS, vmesnikom HEC-GeoRAS in orodjem HEC-RAS sem modelirala poplave Poljanske Sore s 100-letno povratno dobo na odseku od naselja Log nad Škofjo Loko do sotočja Poljanske in Selške Sore v Škofji Loki. Za pripravo slojev geometrije vodotoka sem uporabila podatke LIDAR, na podlagi katerih sem digitalizirala obvezne sloje: središčnico, bregove, linije glavnega toka in prečne profile ter neobvezne sloje: nasipe, območja zastajanja vode, mostove, ovire in rabo tal. S slednjo sem določila Manningov koeficient hrapavosti. Preko vmesnika HEC-GeoRAS sem omenjene podatke izvozila v program HEC-RAS. Tu sem dopolnila podatke o geometriji mostov, ki sem jih dobila z meritvami na terenu. Preden sem lahko zagnala model, sem vnesla še podatke o pretokih in robne pogoje. Rezultat nam prikaže obseg poplav in globino vode. Tega sem najprej prikazala v orodju RAS Mapper in ga nato izvozila v program Arc-GIS, kjer sem modelirane poplave prikazala na ortofoto posnetkih. Globino modeliranih poplav sem prikazala v razredih z istim razponom vrednosti, kot so definirani sloji Območij razredov poplavne nevarnosti. Slednje sem primerjala z dobljenim rezultatom modeliranih poplav in izdelala karte poplavne nevarnosti.

• Language: Slovenian
• Keywords: Poplave, modeliranje, Poljanska dolina, Poljanska Sora, ArcGIS, HEC-RAS
• Work type: Master's thesis/paper
• Organization: FF - Faculty of Arts
• Year: 2019
• PID: 20.500.12556/RUL-108165
• Publication date in RUL: 20.06.2019

Secondary language

• Language: English
• Title: Flood risk modelling of the Poljanska Dolina Valley using HEC-RAS

Abstract

Using the ArcGIS and HEC-RAS software and the HEC-GeoRAS interface, I modelled floods with a 100-year return period on the Poljanska Sora river from the village Log nad Škofjo Loko to the confluence of the Poljanska Sora and Selška Sora rivers in Škofja Loka. On the basis of LIDAR data, I created the geometry of the river with compulsory data, such as stream centerline, bank lines, flow path centerlines, XS cutlines, and non-compulsory data, such as levees, ineffective flow areas, bridges, blocked obstructions and land use. With the latter, I extracted the roughness coefficients, i.e. Manning’s n Values. with the HEC-GeoRAS interface, I exported those data to HEC-RAS where I supplemented it with the geometry of bridges, which I got from the field measurements. I entered flow data and boundary conditions before running the model. The result of flood modelling shows the extent of the floods and the depth of the water. I displayed the result in the RAS Mapper and then exported it in ArcGIS where I displayed the layer of the modelled floods on an orthophoto. I classified the depth of the modelled floods in the classes as defined in the layers of flood risk areas. In the end, I compared those two layers and made the flood risk map.

• Keywords: Floods, modelling, Poljanska Dolina Valley, Poljanska Sora, ArcGIS, HEC-RAS