Adaptation: Water Resources, Water Management, Coastal and Marine Protection

Measures to mitigate the stress or failure of flood protection systems

Floods can occur along all watercourses and, in extreme cases, overwhelm flood protection systems. Flood protection systems can be adapted by reinforcing or constructing new technical flood protection systems. These are mainly dams, dikes, reservoirs, flood retention basins, polders, weirs, local flood protection walls or mobile walls.

In addition to technical measures, measures that serve to create retention areas to hold back water in the area and to restore near-natural watercourse structures are also of great importance. For example, meandering rivers and streams reduce the flow velocity and thus reduce the peak discharge of floods. Floodplains, floodplains and oxbows connected to the watercourse can absorb part of the flood runoff.

In addition, measures for behavioural and structural precautions, for improving flood forecasting, for crisis management and for risk-adapted reconstruction help to prevent damage.

By the end of 2015, nationally and internationally coordinated flood risk management plans were drawn up for all German river basins for the first time. They must be reviewed and updated every six years. For this purpose, hazard and risk maps are drawn up and updated for areas at risk, objectives for dealing with existing risks are formulated and action plans for achieving the objectives are drawn up and further developed.

Indicator from the monitoring on the DAS: Investments in flood protection – case study

Measures to reduce water body temperature and improve biological water quality

High water temperatures can lead to eutrophication of a water body. To prevent this, it is important to reduce nutrient inputs into the water body. This requires measures that help to reduce fertiliser quantities as well as soil erosion and runoff, minimise nutrient inputs by establishing water protection strips, or drain agricultural soils in a more environmentally friendly way. Land-based animal husbandry also contributes to the protection of water bodies from eutrophication. Especially in small and medium-sized water bodies, shading by riparian vegetation can also help to prevent the water from warming up too much.

Groundwater level and groundwater quality

Adaptation measures to declining groundwater levels aim to strike a balance between abstraction and recharge. Groundwater abstraction can be reduced by implementing measures that reduce drinking water consumption. Starting points are, for example, the sprinkling of agricultural areas or the increased use of greywater or rainwater wherever the type of use allows. Groundwater consumption can also be reduced through higher water extraction fees for water-using industries with high environmental impacts, such as agriculture and mining, as well as increased savings incentives for private consumers.

In addition, there are various groundwater recharge strategies, for example through the planned infiltration of additional water volumes. Groundwater recharge can also be promoted through the conversion of coniferous to deciduous forests.

To improve groundwater quality, it is necessary to reduce contamination by nitrate from agricultural sources.

Indicator from the monitoring on the DAS: Water use index

Dam

Dams, like flood retention basins and flood polders, are among the most important elements of technical flood protection.

Source: Boke9a / pixabay

Mobile flood protection wall

Mobile flood protection walls are installed in case of emergency and protect roads and buildings from flooding.

Source: distelAPPArath / pixabay

Natural river course

Natural river course: Near-natural watercourse structures reduce the flow velocity of rivers and thus mitigate flood discharge peaks.

Source: Hans / pixabay

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Measures for adaptation to natural changes on coasts

Measures to adapt to changes in the natural environment can be applied in particular in the area of vegetation development and biotope protection. Renaturation measures are suitable here, such as the construction of wave dampers, the promotion of shallow water areas, the development of foreshore vegetation typical of the natural environment, and the reclamation of tidal flats through, for example, flattening fields. In this way, the biotope conditions in the coastal area and the natural dynamics on coasts are strengthened and the natural regeneration capacity of shore zones is promoted.

Artificial sand flushing can support the growth of tidal flats and the stabilisation of coastal sections at risk of erosion.

Furthermore, concepts of integrative coastal zone management can contribute to the integration of nature conservation measures into coastal protection concepts and thus to mitigating the impacts of climate change on coastal natural areas.

Measures to protect coastal settlements and infrastructure

The extent of damage in coastal areas caused by storm surges and floods depends on the resilience of coastal protection systems. These must be adapted to future requirements. Coastal protection measures include the construction of new dikes or the raising and upgrading of existing ones, the expansion of bank protection systems, sand flushing or the construction or strengthening of storm surge barriers.

In order to reduce the extent of the damage, construction-free zones can be designated near the coast or restrictions on the use of endangered areas can be introduced. The designation of higher premium rates for insurance in flood-prone areas is also a possible instrument.

Indicator from the monitoring on the DAS: GAK funds for flood protection

Measures in the event of overloading of drainage facilities in areas at risk of flooding

In order to provide additional drainage capacities, hydraulic engineering adaptation measures can be carried out, such as the reconstruction or new construction of pumping stations, the new construction or replacement of sluices, the reconstruction or new construction of flood retention basins and an adaptation of the receiving water system. These measures are associated with high costs.

Additional water retention options help to reduce capacity bottlenecks in the drainage system. These include the provision of floodplains, the enlargement or creation of retention areas or the construction or expansion of storage basins.

Another possibility is to start with the form of land use and adapt the management strategy. By flushing out areas at risk of flooding or adjusting target water levels, areas are successively flooded. Agricultural enterprises can adapt here, for example, by using more water-resistant varieties.