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Climate Change Adaptation of

Road Drainage

By Zahra Kalantari

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The PhD project

“Climate Change Adaptation of Road Drainage”

Funded by The Swedish Road Administration (Vägverket)

Operated by KTH, Land and Water Resources Dep.

PhD Student Zahra Kalantari Supervisors: Professor Lennart Folkeson Professor Per-Erik Jansson Professor Bo Olofsson

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MotivationsRoad disruptionAimsMethodologyCommon causes of road damagesImpact of adjacent environment on road

infrastructureExamples of proposed solutions and

mitigations

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Motivations

The climate change will lead to an increase in The frequency of extreme precipitation events

Snow melt periodsFlooding on the roads

Hence the number of incidences on roads will increase.

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Road disruptions

Damages on the roads due to climate change including more frequent floods

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Aims Analyse how climate change directly

or indirectly affects road dewatering and drainage facilities in Sweden

Review the existing problems in road drainage systems focusing on the current Swedish climate

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Aims

Identify future problems considering the climate change including more frequent flood

Study the mitigation regarding the extreme weather events and climate change

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Methodology

International state-of-the-art review Questionnaires

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Common causes of road damages

Water, the major cause of road damages Reduced bearing capacity of the road by water Clogged culverts inlets/outlets

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The insufficient maintenance in form of ditch cleaning and edging

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Lack of planning

Lack of knowledge

Standing water due to improper construction slope along the ditches

No overview over the shortcomings in road drainage

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Limitation in ditch cleaning due to el-/tel cables

Intervals of culvert inspection and clearance

Location of the culverts and road drainage exposed, sensitive and critical to high flows

200-400 million SEK per year in lost efficiency

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Frost heave movements and deformation of the ground surface

In cold climates the risk of frost damage is magnified when water is present

Washed-away roads and landslides due to

Flooding and high flows Inadequate road drainage and

dewatering system dimension Improper road maintenance

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Events require the greatest efforts for maintenance of road drainage system

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Scores

Frost heave

Clear-cut-ground

Oversaturated soil

Landslides

Mechanical damage

Insufficient diameter

Inadequate capacity

Alluviation/ overgrowth in ditches

Overgrowth in pipes, culverts

Blocking of the drainage inlet

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Impact of adjacent environment on road infrastructure

Agricultural area Changes on hydrological

condition due to land use changes

Drained water from the agricultural area

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Forestry Increase in surface water

inflow and runoff

Mud flows and landslides

Fraction of road ditches and soil damage

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Building The more hard surfaces the more surface water

Railways, other landowners and municipalities Deficiencies in railway drainage systems Poorly managed ponds; dam failure

Environmental protection Legislation regarding nature protection

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Examples of proposed solutions and mitigations

Contingency / Inspection

Identify vulnerable points

Identify drainage shortages

Choose the right action

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Examples of proposed solutions and mitigations

Publish a reliable, well documented description regarding road drainage system standards

A business economic analysis model

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Examples of proposed solutions and mitigations

Physical screen

Sealing the culverts and bank slope

Prevent surface erosion by covering the bank

Erosion safe slopes

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Examples of proposed solutions and mitigations

Control dams

Increase the dimension of the road drainage

Extra culverts or drainage pipes

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An often-repeated adage in road construction and maintenance business is:

“The three most important things to understand in building and

maintaining road are drainage, drainage, and drainage”

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