DBPapers
DOI: 10.5593/SGEM2016/B31/S12.029

CREATING HYDROLOGICAL RISK MAPS BASED ON THE RECTIFIED DIGITAL TERRAIN MODEL IN THE NICOLINA HYDROGRAPHICAL BASIN

M.Diac, C. Chirila,V.E.Oniga, H.I.Hogas
Wednesday 7 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-61-2 / ISSN 1314-2704, June 28 - July 6, 2016, Book3 Vol. 1, 219-226 pp

ABSTRACT
The creation of hydrological risk maps is based on the existence of a Digital Terrain Model which is hydrologically correct. Although, one of the most used data sources for the Digital Terrain Model (DTM) generation is the Airborne Laser Scanner data (ALS), the DTM being performed by different interpolation methods, its accuracy must be improved by modelling the local geoid / quasigeoid, in order to obtain flooding bands with different probabilities of recovery.
In this case, a combined analytical and geometrical model for the creation of a corrector surface that affects the gravimetric quasigeoid model was applied, but it "fits" the Global Navigation Satellite System (GNSS) / levelling determinations and serves the practical issue by leading to better results in correcting height anomalies for subsequent hydrologic analyses. Three geopotential models have been used, a global one (Earth Gravitational Model 2008 - EGM2008) and two regional ones (European Gravimetric Geoid 97 - EGG97, European Gravimetric Geoid 2008 - EGG2008), which finally led to results close in accuracy, but better than those offered by TransDatRO official application of the National Agency for Cadastre and Land Registration.
Finally, based on the rectified Digital Terrain Model, the hydrologic flow modelling is presented in specialized software (Hydrologic Risk) in order to assess hydrological risk areas with different probabilities of recovery.
The case study in Nicolina hydrological basin area has revealed the flooding bands, which can be an effective tool for local authorities to reduce damages in case of hydrological risk. Although, at first sight, the flood risk of the study area appears not to be very large, the implications of localities isolation even for 24 hours in the case of sanitary emergency, fire, etc., should be considered.

Keywords: DTM, quasigeoid, hydrologic, map, risk.