Tool RISK REDUCTION MEASURES

Settlement areas are often more vulnerable to damages from heavy rain events than surrounding areas.

Typical hazards and risks

• The capacities of the sewage system and drainage canals cannot absorb the rainfall or water leaks out of the sewage system at various points, e.g. in streets, basements.
• Fast running surface water with a harmful destructive power (in hilly and mountainous terrain)
• Blocking, damages and sedimentation to surface water drains
• Flooded or destroyed streets
• Swamped cellars and ground levels of buildings
• Destroyed, uninhabitable homes
• Power outage
• Disruptions in traffic, operation or supplies
• Disruptions in (tele-)communication
• Commercial losses
• Despaired citizens and/or citizens in panic

Strategies for reducing risks

Heavy rain resilient, water-sensitive and climate-resistant urban development are central action strategies for settlement areas. Citizens, business people and property owners should be involved.

• Prevent damages by considering a wide range of measures, e.g. decentralise and enhance surface water drainage systems in urban areas.
• Retain rainwater, e.g. maximise water retention capacities within settlement structures by natural and artificial solutions (“sponge city”).
• Adapt spatial planning, e.g. keep flood prone areas and runoff pathways free from building developments.
• Improve early warning and organise emergency response.

Heavy rainfall can cause damages to crops and to soil due to erosion processes. Agricultural surface runoff can carry sediments and nutrients into built-up areas, streams or habitats.

Typical hazards and risks

• Crop losses due to extensive and long-term flooding and waterlogging in flat terrain
• Complaints about mud deposit in properties situated below farmland in hilly terrain
• Dangerous landslides in mountainous terrain
• Crop losses due to mud covered or washed away plants and seeds;
• Animals drown
• Loss or compaction of soil
• Impairment of protected areas/species

Strategies for reducing risks

Measures focussing on a sustainable soil management and on the implementation of natural water retention measures are key approaches for risk reduction here. They offer benefits also for other extreme weather conditions, e.g. drought situations. Owners of farmland and farmers should be involved.

• Prevent damages! In case of risks at site (e.g. waterlogging, erosion), care about better drainage and/or adaption of management practices and land use (e.g. by grassing).
• Retain rainwater! Use preferably (natural) water retention Ensure compliance of farming practices with regulations for the sustainable protection of soil.

Even after heavy rainfall there is almost no surface runoff in healthy and site-appropriate forests. Forests offer optimal conditions for the evaporation and infiltration of rainwater.

Typical hazards and risks

• Losses in yields
• Damages (erosion) on forest paths and clearings
• Damages by driftwood in lower-lying areas in hilly and mountainous terrain
• Dangerous landslides in mountainous terrain

Strategies for reducing risks

Measures focussing on a sustainable forest management and on the implication of natural water retention measures are key approaches for risk reduction in this field of action. Forest owners and forest managers should be involved.

• Prevent damages! In case of damages at site (e.g. erosion), care about better drainage and/or adaption of management practices and improvement of forest health (e.g. rejuvenation); allow natural succession.
• Retain rainwater! Use preferably (natural) water retention measures.

An overflow of water from water bodies to surrounding areas (river flooding) is subject to conventional flood risk management planning. However, after heavy rainfall, major problems can occur in and along watercourses even without significant river flooding.

Typical hazards and risks

• Pollution from inflow of surface water and drainage water – causing impairment of protected areas/species due to bad water quality.
• Large debris washed away – causing damages to banks, bridges and to physical flood management structures.
• Erosion and reservoir sedimentation – leading to reduced storage in reservoirs or changes of the flow capacity of riverbeds and canals.

Strategies for reducing risks

Consideration of heavy rain risks in flood risk management planning, an integrated water management as well as the implementation of natural water retention measures are key approaches for risk reduction in this field of action.

• Retain rainwater! Increase the water retention capacity of waterbodies e.g. by reconnecting them to the backwater.
• Combine flood risk management planning from the EU Floods Directive with planning and monitoring processes according to the EU Water Framework Directive. Work towards a holistic and collaborative integrated River Basin Management planning.

Typical hazards and risks

• Water penetrates through building’s openings
• Backpressure of sewerage water
• Damage to materials
• Mud deposition and contamination
• Disruptions in electricity, (tele-)communication, supplies
• Danger to life! (drowning, electrocuting, crushing after roof or wall collapse, …)
• Traumatic feelings (fear, powerlessness, traumatisation)
• Homes become uninhabitable
• Loss of memorabilia, pets and valuables

Strategies for reducing risks

Measures related to buildings (and properties) are mostly protective measures. But also implementation of retention measures is an important task for property owners.

• Prevent damages! Divert surface water away from buildings. Protect existing buildings esp. in flood prone areas and runoff pathways. Make your private emergency plan!
• Retain rainwater! Maximise water retention on properties.