Description of the Hydrological Observatory Bode

The Bode river catchment in the TERENO Harz/Central German Lowland Observatory is the central study site for water-related research at the Helmholtz Centre for Environmental Research - UFZ. The Bode catchment is a mesocale, lower mountain range catchment (total area: 3,300 km², see figure 1; click opens a larger image) within the Elbe river basin. The area shows large topographic gradients (altitude: 55 - 1,100 m above mean sea level) and climatic variability (mean annual temperature approx. 9°C). Mean annual precipitation amounts to an average 660 mm with large spatial and temporal variability (450 - 1,600 mm; maximum in summer). The Geology of the Bode catchment is dominated by schist and claystone in the headwaters (ca. one third of the catchment area), and tertiary sediments with loess soils in the lower parts of the catchment (ca. two third of thecatchment area). Previous studies concentrate on runoff generation in small headwater catchments of the Bode/Selke River. Digital soil data are available at the scale of 1:50000 for the whole catchment and several long term soil survey filed sites for different soil types within the catchment. The area is dominated by agricultural use (70 % of the catchment). The middle mountain area of the Harz is dominated by forest use. Urban areas make up around 6 % (total population 370,000), industrial areas and open-pit mining areas each cover approx. 1 % of the land surface.

The catchment represents one of the best meteorologically and hydrologically equipped catchments in Central Germany (long term data discharge, precipitation, climate). The Bode catchment has an already existing dense precipitation, climate and discharge gauges network (see figure 1; click opens a larger image). Weather radar from the German Weather Service is also available. Furthermore, long term water quality monitoring by environmental agencies is in place (some of them are recorded for more than 50 years). Water availability in the catchment is generally good, and becomes an issue only in the lower parts of the catchment, where mean annual precipitation falls below 500 mm.

Current surveys conducted in the course of the implementation of the WFD suggest that 76% of the river system it is unlikely or unsure to reach a good ecological status, caused by high nutrient loads and heavily modified river morphology (29 % unlikely, 27 % unsure). The Bode catchment comprises four groundwater bodies, of which three have been classified as in bad chemical status, resulting from diffuse pollution (as of September 2006), but all are currently classified as in good status in respect to water quantity.

The most widespread problem within the catchment with regard to groundwater/surface water systems is eutrophication due to solute inputs from agriculture (N, P). Future land use change (e.g. shifting to energy plants) may increase agricultural inputs to surface waters. Climate change has already altered and may further alter the hydrological regime (i) with an increase of winter precipitation, and decrease of summer precipitation, and reduced water residence times, (ii) with effects on the ecohydrological boundary conditions of the river system and (iii) with changing effects on the interactions between groundwater and surface water especially in the summer season.

The Bode river catchment is the central study site for water-related research at the UFZ. As integral part of the TERENO observation network an integrated monitoring and research concept joining hydrological, atmospherical, biodiversity related, and soil physical research has been implemented.. This will lead to scale-dependent intensive research activities on different spatial scales ranging from point sampling to remote sensing, following a nested approach. Thus, it offers the possibility for a joined processing of central research questions from the point via the plot scale up to the catchment scale; and it constitutes one region sensitive to climate change where a regional model will be calibrated and applied for predictive scenarios.

Integral part of the nested catchment monitoring approach are intensive test sites offering the possibility to investigate several hydrological, pedological and ecological processes of relevance in a very detailled manner. Currently five intensive test sites are implemented (click on the titles opens a more detailled description):

Hohes Holz - Forest ecohydrology and trace gas fluxes
Sauerbach - Quantification of water and solute fluxes within and out of an agriculturally intensively used catchment
Selke - Hyporheic zone dynamics
Schäfertal - Understanding the functioning of the terrestrial system using novel observation and modeling techniques An interdisciplinary approach
Rappbode Reservoir - DOC, water and matter fluxes within a drinking water reservoir and catchment

Research Platform Middle Elbe - an interdisciplinary research platform for floodplain ecology in the Middle Elbe

A multidisciplinary research platform has been established in the UNESCO Biosphere reserve Middle Elbe Different scientific groups inside and outside the UFZ are working together to understand floodplain ecology, functioning andgps campaign flood plain research plattform management. The platform is in the continuum of the successful multidisciplinary collaboration developed within the RIVA and HABEX projects which has allowed the collection of valuable data on floodplain ecosystems since 1998. One key activity is the Rosslau experiment.

The Rosslau experiment offers the unique opportunity to follow the first implemented floodplain restoration project in the UNESCO biosphere reserve Riverine Landscape Elbe. It is assumed that reactivated floodplains will restore dynamic alluvial habitats with high biodiversity and reinforce the multiple floodplain functions. The assessment of the effects of such restoration measures requires long-term research platforms for interdisciplinary research. An integrated multidisciplinary approach was chosen to study complex floodplain dynamics and interactions between the different environmental compartments successfully.

Since spring 2006, a multidisciplinary research platform is established by the UFZ to study exemplarily short-term and long-term effects of floodplain restoration on floodplain ecosystem services and functions in thescheme of study design Rosslau area. According to the needs to study effects of floodplain management, three different sub-areas have been chosen: restoration area, untouched active floodplain, and disconnected floodplain. The stratified, randomised study design with interdisciplinary study plots sets the scientific basis to all participating disciplines and is to be considered as the core of the research platform. It enables repeated surveys of the same plots for biotic (molluscs, insects, vegetation) and abiotic (soil, nutriments, pollutants, hydrology) factors.

Project objectives are:

• Analyses of biodiversity and ecosystem services in floodplains
• Quantification of filtration, transport and buffering processes
• Test of non-invasive monitoring methods for hydrogeology studies
• Prediction of habitat function using biological and environmental factors
• Assessment of potential effects of climate change on floodplain functions and biodiversity
• Integrated approach for mosquito management in floodplains
• Evaluation of the dike relocation from a socio-economical point of view
• Transferability of the results to other floodplain sectors or river systems

Further information about the Research Platform Middle Elbe (via UFZ)

Interdisciplinary research platform in the urban agglomeration Leipzig - Halle

The urban system applies to the area of conflict between urban growth and shrinkage exemplified on the urban agglomeration Leipzig - Halle. Short-term and long-term effects of urban dynamics are investigated on different scales, from the entire urban region to neighbourhoods, from the urban landscape to single objects (house, tree).

Fig. 1: Urban agglomeration Leipzig - Halle

The urban observatory is based on the following methodological toolkits:

• Dynamic land-use processes and socio-demographic developments are monitored by means of remote sensing data and techniques, GIS, statistical data including cartographic modelling
• Recording exchanges of matter (water, carbon and energy balance, pollutant fluxes and concentrations, climate parameters) using field measurements and analyses of statistical data
• Observing socio-spatial differentiation and residential site investigations through questionnaires and interviews

Fig. 2: Monitoring the urban system – test site City of Leipzig

The flow chart exemplifies recent and actual studies and results for the City of Leipzig. Main driver of environmental risks are demographic developments, and their dynamics started to be uncoupled from land-use changes. They show strong impact on environmental quality and quality of life in the urban area. In addition, environmental influences such as exposition to air pollution (in the graph: individual specific exposure) lead to conflicts. The complex processes must be investigated in case studies and at various scales to estimate the different social, economic and environmental values and to make recommendations for policy implementations. In this respect it is important to understand the multi-level governance structures.

The central fields of transformation are:

• Resource-efficient city
  It aims at reducing resource consumption regarding space, green infrastructure, ecosystem services, energy and water. Retroactive effects onto other compartments need to be monitored as well. The observatory is carried out by means of field work, remote sensing and GIS analysis, modelling and investigation of governance structures.

• Livable city
  It demands quality of life, environmental justice and health for all residents with respect to climatological, demographic and social characteristics. Focussing on living and residential neighbourhoods, different life styles, but also air pollution or green space equipment, the observations are undertaken with various quantitative (remote sensing, statistical data) and qualitative (interviews) methods.

• Resilient city
  It is based on the capability to cope with extreme events such as flooding, droughts, heat waves or consequences of climate change especially environmental risks and shock. Observation techniques cover the combination of modelling, smart sensors and socio-demographic data (statistics and questionnaires).

Pesticide Exposure and Effect Assessment Initiative

Figure 1: Overall structure and participant of the Pesticide Exposure and Effect Assessment Initiative, TERENO 2010.In 2010 the Pesticide Exposure and Effect Assessment Initiative was started in the Harz/Central German Lowland Observatory. The aim of this research initiative is to identify the contamination and ecological impacts in freshwaters caused by agricultural pesticides at the large spatial scale. That is a nontrivial scientific task due to complexity of the natural systems and typical current multi-stress environment.

The work is performed by a whole group of researchers from several departments of UFZ, University of Aachen, and University of Ilmenau (see figure 1, click opens a larer image) and coordinated by the Department of System Ecotoxicology, UFZ.

Sampling network includes twenty sample sites that were selected after GIS-modeling aimed at predicting the pesticide run-off (Fig. 2). The pesticide exposure is investigated using sophisticated sampling methods such as passive samplers and event-driven samplers. Ecological effects are identified using the trait-based indicator system SPEAR.

Figure 2: Sample sites in the TERENO, Harz Central Germany Lowland area