Table of contents
- Draft key messages
- Executive summary
- 1 Introduction - 1.1 Scope of theme: Why care about floodplains?
- 1 Introduction - 1.2 The catchment-river-floodplain ecosystem and policies
- 2 Floodplains under pressure - 2.1 Floodplain characteristics and extent
- 2 Floodplains under pressure - 2.2 Current floodplain status in Europe
- 2 Floodplains under pressure 2.3 - Climate change and altered flood risk
- 2 Floodplains under pressure - 2.4 Hydromorphological pressures and alterations
- 2 Floodplains under pressure - 2.5 Pollution pressures
- 3 Improving ecosystem services and measures - 3.1 Ecosystem services
- 3 Improving ecosystem services and measures - 3.2 Measures
- 3 Improving ecosystem services and measures - 3.3 Examples of river and floodplain restoration
- 4 Managing from an ecosystem perspective
- 5 Conclusions and Outlook
- References
- Annex 1 European and Global Policy Context
- Annex 2 Definitions
- Annex 3 Ecosystem service overview
- Annex 4 Measures that improve services
2 Floodplains under pressure - 2.4 Hydromorphological pressures and alterations
Within river basin districts, socio economic drivers generate a multitude of human activities that rely on the natural system. Important activities are agriculture and forestry, urbanization and transport, flood protection, hydropower production, navigation and recreation, that all, but in different ways, add pressure to the river-floodplain ecosystem. These changes are linked to the need to provide flood protection of people and property and to the historical desire to increase agricultural area, but also navigation and mining have added to pressures. Such pressures are broadly referred to as hydromorphological pressures – pressures to the natural system from changes to both hydrology (water flow) and morphology (physical characteristics) of rivers and floodplains.
Hydromorphological pressures covers a very wide range of changes, that all have different ways of influencing survival species, habitats and even ecosystems. The changes introduced by hydromorphological pressures impact the ecology of the natural system. They have a tendency to eliminate the lateral connectivity between the river and floodplain, reducing habitat quality, and influencing the species that can thrive. For example, barriers across rivers prevent fish from migrating upstream, reducing the ability of migratory fish to reach spawning areas. In Norway, following pressures from escaped farmed salmon and salmon lice, hydromorphological pressures are seen as the largest single factor influencing the wild salmon population (Forseth et al., 2017).
Under the Water Framework Directive, hydromorphological pressures are captured as one of the quality elements supporting the achievement of good ecological status. I.e. if benthic invertebrate fauna, fish or aquatic vegetation fail to achieve good ecological status, the possible impact of hydromorphological pressures needs to be assessed. The recent overview of the results in the second River Basin Management Plans under the Water Framework Directive show that hydromorphology is a significant pressure in 45% of Europe’s rivers, with physical alterations to floodplains or the river channel accounting for 30% of those pressures, and dams, locks and weirs account for another 27% (EEA, 2018b, 2018c). The average value, however, masks large geographical variations, with some countries not reporting hydromorphological pressures and other reporting 85% of waterbodies impacted. Some examples of hydromorphological alterations linked to pressures are listed in Box 2, and the hydromorphological alterations of the Tisza river, Hungary is provided as an example of the large modifications Europes rivers have undergone (Box 3).
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that all have different ways of influencing survival species, habitats and even ecosystems. better "survival rate" of species?
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1st paragraph could be more clearly formulated. "These changes are linked to the need to provide..." - not clear to which changes this refers to, as the sentence before mentions activities.
Proposed better wording for last sentence "Such pressures which cause change to both hydrology...and morphology.. or rivers and floodplains are broadly referred to as hydromorphological pressures".
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3rd para: See my comment in section 1.2. on more correctly describing the role of hydromorphology in assessment of ecological status.
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Text part about channel normalisation: Would be good to refer to box 3.
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Suggest more on smaller barriers. Recent UK research identified only 97% of the river network in UK is fragmented and <1% of catchments are free of articicial barriers. https://amber.international/wp-content/uploads/2019/04/Jones_etal_2019.pdf
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Dikes, dams etc are "hydromorphological pressures" according to a glossary now being developed by CIS experts on hydromorphology.
"Hydromorphological alterations" are alterations in the hydromorphological conditions which are caused by physical modification(s). Therefore, a dam is the pressure and hydromorphological alteration would be e.g. disruption of continuity, flow changes etc.
Therefore, I suggest that you replace the term alterations in the Box with pressures.
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HU
Box 2, Dikes and Tisza river example: Tisza River shows that same discharge values have ascendant water levels (the same amount of discharge flows at higher water levels). This is due to floodplain sedimentation. Narrow active floodplains on lowland are the recipient of sediment since more than 170 years. -
HU
Dams: downstream stretches of the dams, a lack of sediment can occur, which can lead to deepening of the riverbed, floodplain cut off and lowering of the groundwater level.
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"socio economic drivers" should be with hyphen ("socio-economic drivers").
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Box 2, first sentence: verb should be in plural number.
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Box 2, second paragraph: "Such changes often leads ...": Verb should be in plural number.
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Box 2, paragraph on "dams": "In 1950, 1,210 large dams were distributed" - perhaps better "were located".
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Box 2, paragraph on "dams": "the Balkan countries" instead of only "Balkan countries"
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Box 3, table: Unit cubing/squaring should be superscript (also relevant for all other tables in the report).
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Line 3: pressure on (instead of to)
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NI.
Box 2 – Query the term Normalization? Makes it seem almost desirable.
Dikes – Should emphasise that they encourage agricultural development as well as industrial and urban. Most ‘Dikes’ in Ireland are in place to protect agricultural land
First sentence of 2nd text part: 'Hydromorphological pressures covers a very wide range of changes, that all have different ways of influencing survival species, habitats and even ecosystems'.
I would prefer to change the order to: '....influencing habitats, the survival of species, interactions between them and, therefore, even whole ecosystems.'