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Road structures under climate and land use change

Publicerad 2014-02-14

Dissertation: Road structures under climate and land use change - Bridging the gap between science and application

Respondent: Zahra Kalantari

Time: Friday 14 February at 10.00

Place: Room V1, Teknikringen 76, KTH

Opponent: Professor Hans-Peter Nachtnebel, Institute for Water Management, Hydrology and Hydraulic Engineering, University of Natural Resources and Life Sciences, Vienna, Austria

Abstract

Future changes in climate and land use are likely to affect catchment hydrological responses and consequently influence the amount of runoff reaching roads. Blockages and damage to under-dimensioned infrastructure can be extremely costly for the regions affected. This study aims to produce scientifically well-founded suggestions on adaptation of road drainage systems to climate changes resulting in more frequent floods. This thesis demonstrates
the need to integrate aspects of climate change and land use impact into the planning and practice of road construction and maintenance in Sweden. Tools such as hydrological models are needed to assess impacts on discharge dynamics. Identifying a 'best' practically performing hydrological model is often difficult due to the potential influence of modeller subjectivity on calibration procedure, parameter selection, etc. Hydrological models may need to be selected on a case-by-case basis and have their performance evlauated on an application-by-application basis.

The work presented here began by examining current practice for road drainage systems in Sweden. Various hydrological models were then used to calculate the runoff from a catchment adjacent to a road and estimate changes in peak discharg and total runoff resulting from simulated land
 use measures. Overall, the results indicate that the specific effect of land use measures on catchment discharge depend on their spatial distribution and on the size and timing of storm events. Scenarios comprising a changing climate up to 2050 or to 2100 and orest clear-cutting were used to determine whether the current design of road drainage construction is sufficient for future conditions. Based on the findings, the approach developed can be used for similar studies, e.g. by teh Swedish Transport Administration in dimensioning future road drainage structures to provide safe and robust infrastructure.

Furthermore, a statistical method was developed for estimating and mapping flood hazard probability along roads using road and catchment characteristics. The method allows flood hazard to be estimated and provides insight into the relative roles of landscape characteristics in determining road-related flood hazards. Overall, this method provides an efficient way to estimate flooding hazards and to inform the planning of future roadways and the maintenance of existing roadways.

Keywords

Adaptation, extreme rainfall events, runoff, land use, climate change, flood hazard

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A cooperation between the research groups Environmental Management and Assessment and   Environmental Physics , at the Division of Land and Water Resources Engineering, KTH.

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