Grundwasser - Altlasten aktuell

Neun Fachbeiträge dokumentieren die Ergebnisse der aktuellen Projekt- und Forschungsarbeit des Landesamtes im Bereich Grundwasser und Altlasten. Themen sind u. a. diffuse Schwermetallbelastungen in 10 Grundwasserkörpern, die nach Wasserrahmenrichtlinie im schlechten chemischen Zustand ausgewiesen wurden, die Umsetzung der EG-Wasserrahmenrichtlinie in von Punktquellen beeinflussten Grundwasserkörpern und die bisherigen Ergebnisse des internationalen Projektes SHARP. Weitere Beiträge befassen sich mit dem Bearbeitungsstand und dem Handlungsbedarf der im Sächsischen Altlastenkataster (SALKA) erfassten Flächen, dem Gefährdungspotenzial von Gärtnereien und den altlastenbezogenen Bewertungs- und Analyseempfehlungen für kurzkettige Alkylphenole

Topographical factors related to flooding frequency promote ecosystem multifunctionality of riparian floodplains

Various ecosystem functions provided by floodplains depend on a natural river activity and floodplain morphology. Therefore, anthropogenic alterations of rivers modify their flooding regimes and may affect the provisioning of numerous ecosystem functions. Restoration projects, which aim at reestablishing natural processes of floodplains, require a better understanding of the ecosystem's ability to simultaneously provide multiple functions (multifunctionality) and how this relates to the environmental template. Here we investigate the relationship between environmental drivers and ecosystem multifunctionality. We focus on 24 ecosystem functions, representing five ecosystem services provided by floodplains of the Mulde River: plant productivity, biodiversity provisioning, retention of sediments, nutrients and pollutants. These functions were measured on 74 plots located on three well preserved floodplain sites of the Mulde River. We described synergies and trade-offs between single functions using correlations and calculated quantitative measures of ecosystem multifunctionality, quantified as the number of functions provided above either 50% of maximal functioning, or 75% of maximal functioning. We then explored relations of multifunctionality with two environmental factors, which also affect the probability of flooding i.e., the hydrological distance and the distance to the water table. Although numerous functions related to sedimentation processes were positively correlated to each other, they traded off with functions related to biodiversity provisioning. This advocates the application of a holistic measure of ecosystem functioning. Multifunctionality indices decreased with an increase of both distance to the water table and hydrological distance, with effects of the distance to the water table being most strongly negative. These findings imply that ecosystem multifunctionality is highest at sites which are flooded regularly. We conclude that restoration attempts which shorten hydrological distance and distance to the water table, like removal of artificial embankments or reconstruction of side channels, may have a positive effect not only on single functions, but also on overall ecosystem multifunctionality. We also advocate the application of a multifunctionality measure to facilitate management and restoration of floodplains

Vegetation characteristics control local sediment and nutrient retention on but not underneath vegetation in floodplain meadows

Sediment and nutrient retention are essential ecosystem functions that floodplains provide and that improve river water quality. During floods, the floodplain vegetation retains sediment, which settles on plant surfaces and the soil underneath plants. Both sedimentation processes require that flow velocity is reduced, which may be caused by the topographic features and the vegetation structure of the floodplain. However, the relative importance of these two drivers and their key components have rarely been both quantified. In addition to topographic factors, we expect vegetation height and density, mean leaf size and pubescence, as well as species diversity of the floodplain vegetation to increase the floodplain's capacity for sedimentation. To test this, we measured sediment and nutrients (carbon, nitrogen and phosphorus) both on the vegetation itself and on sediment traps underneath the vegetation after a flood at 24 sites along the River Mulde (Germany). Additionally, we measured biotic and topographic predictor variables. Sedimentation on the vegetation surface was positively driven by plant biomass and the height variation of the vegetation, and decreased with the hydrological distance (total R2 = 0.56). Sedimentation underneath the vegetation was not driven by any vegetation characteristics but decreased with hydrological distance (total R2 = 0.42). Carbon, nitrogen and phosphorus content in the sediment on the traps increased with the total amount of sediment (total R2 = 0.64, 0.62 and 0.84, respectively), while C, N and P on the vegetation additionally increased with hydrological distance (total R2 = 0.80, 0.79 and 0.92, respectively). This offers the potential to promote sediment and especially nutrient retention via vegetation management, such as adapted mowing. The pronounced signal of the hydrological distance to the river emphasises the importance of a laterally connected floodplain with abandoned meanders and morphological depressions. Our study improves our understanding of the locations where floodplain management has its most significant impact on sediment and nutrient retention to increase water purification processes

Grundwasser - Altlasten aktuell

Neun Fachbeiträge dokumentieren die Ergebnisse der aktuellen Projekt- und Forschungsarbeit des Landesamtes im Bereich Grundwasser und Altlasten. Themen sind u. a. diffuse Schwermetallbelastungen in 10 Grundwasserkörpern, die nach Wasserrahmenrichtlinie im schlechten chemischen Zustand ausgewiesen wurden, die Umsetzung der EG-Wasserrahmenrichtlinie in von Punktquellen beeinflussten Grundwasserkörpern und die bisherigen Ergebnisse des internationalen Projektes SHARP. Weitere Beiträge befassen sich mit dem Bearbeitungsstand und dem Handlungsbedarf der im Sächsischen Altlastenkataster (SALKA) erfassten Flächen, dem Gefährdungspotenzial von Gärtnereien und den altlastenbezogenen Bewertungs- und Analyseempfehlungen für kurzkettige Alkylphenole

Grundwasser - Altlasten aktuell

Neun Fachbeiträge dokumentieren die Ergebnisse der aktuellen Projekt- und Forschungsarbeit des Landesamtes im Bereich Grundwasser und Altlasten. Themen sind u. a. diffuse Schwermetallbelastungen in 10 Grundwasserkörpern, die nach Wasserrahmenrichtlinie im schlechten chemischen Zustand ausgewiesen wurden, die Umsetzung der EG-Wasserrahmenrichtlinie in von Punktquellen beeinflussten Grundwasserkörpern und die bisherigen Ergebnisse des internationalen Projektes SHARP. Weitere Beiträge befassen sich mit dem Bearbeitungsstand und dem Handlungsbedarf der im Sächsischen Altlastenkataster (SALKA) erfassten Flächen, dem Gefährdungspotenzial von Gärtnereien und den altlastenbezogenen Bewertungs- und Analyseempfehlungen für kurzkettige Alkylphenole