Sediment management of rivers and Water Framework Directive: the case of the Spree River

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Michael Nones

Friday 3 july 2015

8:30 - 8:45h at South America (level 0)

Themes: (T) Sediment management and morphodynamics, (ST) Basin-wide sediment management

Parallel session: 14J. Sediment - Basin

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The European Water Framework Directive 2000/60/EC (WFD) is one of the most important legislative instrument introduced in the field of water policy during the last 40 years. Its main goals are to achieve, at least, a good ecological and chemical status for surface waters and a good quantitative and chemical status for groundwater by 2015, on the basis of a basin management approach. Despite of its advanced theoretical background, this Directive presents some weakness, such as the negligence of the hydromorphological elements into the classification system of water bodies. Potentially, this lack could permit further alteration of waters and the failure of the Directive’s goals. Hydromorphological aspects provide an essential support in a variety of environmental processes, such as purifying pollutants, recharging ground waters, reducing the erosive action of floods on infrastructures. On the other hand, hydromorphological conditions constitute fundamental features of any water bodies and have an intrinsic value of existence, regardless their supporting role for biological elements. In contrast with their important and recognized role for ecosystem, the WFD explicitly considers the hydromorphological elements only in the case of water bodies with a “high” ecological status (or maximum ecological potential, for heavily modified and artificial bodies). The assignment of water bodies to the “good ecological status” (or good ecological potential) class is made only on the basis of biological and physico-chemical monitoring results, while the other three classes (“moderate”, “poor” and “very poor”) rely only on biological quality elements. In this light, the revision process of the WFD Basin Management Plans, forecasted in 2016, requires a more widespread consideration of the hydromorphological elements. To give an example of the strict relationship between sediment transport and ecological status of rivers, a reach of the Spree River near Cottbus, Brandenburg, Germany, is studied. In this reach a restoration project, beginning in 2006, has the aims to increase the ecological status of the river and fulfil the WFD goals, but the suspended sediment transport of sand, especially in correspondence with flooding events, could threaten these objectives. For this reason, in addition to the River Basin Management Plan required by the WFD, a sediment management plan at basin scale is necessary.