Präsentation der Forschungsergebnisse. Klimatische Veränderungen und Reaktionen der Seen, Anpassungsstrategien und die Schwierigkeit, diese umzusetzen.
Proceeding of the 12th International Conference on Urban Drainage, Porto Alegre/Brazil, 11-16 September 2011.
For the development of adaptation strategies in the research project dynaklim (Dynamic Adaptation of Regional Planning and Development Processes to the Effects of Climate Change in the Emscher-Lippe-Region) numerous models (e. g. sewer models) which need rainfall data as input are used. These models need data with a temporal and spatial resolution beyond the resolution provided by regional climate models. Therefore downscaling of the
precipitation data is performed with the help of weather radar data. Comparisons of measurement and model data during 1961-1990 show systematic bias and differing statistical characteristics between the two data types; thus the model data requires preliminary correction before use. A critical point is the corrections´ impact on extreme event data that are applied in extreme value statistics for structure design, e.g. for retention basins. Different characteristics of the analysed rainfall data and correction procedures are described.
Dies ist ein Poster aus dem REGKLAM-Vorhaben zum Thema "Projizierte Trockenheitstrends - Bewertung regionaler Trockenheitstrends anhand eines Ensembles globaler und regionaler Klimamodelle".
Dieses Rechtsgutachten umfasst 6 Kapitel aus dem Bereich Raum- und Bauplanung mit Bezug zur Anpassung an den Klimawandel und seinen Folgen:
A) Bauleitplanung
B) Bauordnungsrecht
C) Raumordnungsrecht
D) Naturschutzrecht
E) Wasserrecht
F) Anpassung in den Umweltprüfungen
Abstract
Water management and environmental protection is vulnerable to extreme low flows during streamflow droughts. During the last decades, in most rivers of Central Europe summer runoff and low flows have decreased. Discharge projections agree that future decrease in runoff is likely for catchments in Brandenburg, Germany. Depending on the first-order controls on low flows, different adaption measures are expected to be appropriate. Small catchments were analyzed because they are expected to be more vulnerable to a changing climate than larger rivers. They are mainly headwater catchments with smaller ground water storage. Local characteristics are more important at this scale and can increase vulnerability.
This thesis mutually evaluates potential adaption measures to sustain minimum runoff in small catchments of Brandenburg, Germany, and similarities of these catchments regarding low flows. The following guiding questions are addressed: (i) Which first-order controls on low flows and related time scales exist? (ii) Which are the differences between small catchments regarding low flow vulnerability? (iii) Which adaption measures to sustain minimum runoff in small catchments of Brandenburg are appropriate considering regional low flow patterns?
Potential adaption measures to sustain minimum runoff during periods of low flows can be classified into three categories: (i) increase of groundwater recharge and subsequent baseflow by land use change, land management and artificial ground water recharge, (ii) increase of water storage with regulated outflow by reservoirs, lakes and wetland water management and (iii) regional low flow patterns have to be considered during planning of measures with multiple purposes (urban water management, waste water recycling and inter-basin water transfer). The question remained whether water management of areas with shallow groundwater tables can efficiently sustain minimum runoff. Exemplary, water management scenarios of a ditch irrigated area were evaluated using the model Hydrus-2D. Increasing antecedent water levels and stopping ditch irrigation during periods of low flows increased fluxes from the pasture to the stream, but storage was depleted faster during the summer months due to higher evapotranspiration. Fluxes from this approx. 1 km long pasture with an area of approx. 13 ha ranged from 0.3 to 0.7 ls-1 depending on scenario. This demonstrates that numerous of such small decentralized measures are necessary to sustain minimum runoff in meso-scale catchments.
Differences in the low flow risk of catchments and meteorological low flow predictors were analyzed. A principal component analysis was applied on daily discharge of 37 catchments between 1991 and 2006. Flows decreased more in Southeast Brandenburg according to meteorological forcing. Low flow risk was highest in a region east of Berlin because of intersection of a more continental climate and the specific geohydrology. In these catchments, flows decreased faster during summer and the low flow period was prolonged. A non-linear support vector machine regression was applied to iteratively select meteorological predictors for annual 30-day minimum runoff in 16 catchments between 1965 and 2006. The potential evapotranspiration sum of the previous 48 months was the most important predictor (r2 = 0.28). The potential evapotranspiration of the previous 3 months and the precipitation of the previous 3 months and last year increased model performance (r2 = 0.49, including all four predictors). Model performance was higher for catchments with low yield and more damped runoff. In catchments with high low flow risk, explanatory power of long term potential evapotranspiration was high.
Catchments with a high low flow risk as well as catchments with a considerable decrease in flows in southeast Brandenburg have the highest demand for adaption. Measures increasing groundwater recharge are to be preferred. Catchments with high low flow risk showed relatively deep and decreasing groundwater heads allowing increased groundwater recharge at recharge areas with higher altitude away from the streams. Low flows are expected to stay low or decrease even further because long term potential evapotranspiration was the most important low flow predictor and is projected to increase during climate change. Differences in low flow risk and runoff dynamics between catchments have to be considered for management and planning of measures which do not only have the task to sustain minimum runoff.
Ziel von ‚nordwest2050‘ ist es, die Metropolregion Bremen-Oldenburg im Nordwesten auf die Folgen des Klimawandels und die damit verbundenen Unsicherheiten vorzubereiten. Aber wie können wir heute Handlungspfade bis ins Jahr 2050 beschreiben, die auch unter noch unbekannten Rahmenbedingungen und trotz unerwarteter Entwicklungen zum Ziel führen? Wie kann man dabei die vielen weiteren Herausforderungen der Zukunft berücksichtigen, wie beispielsweise Strukturwandel, Finanzkrise und Demografischer Wandel?
The survey of 4.000 companies in the metropolitan area of Bremen-Oldenburg in north-western Germany conducted by the University of Oldenburg as part of the ‚nordwest2050’ project in 2010 and 2012 showed that the economic importance of climate change is growing. The 2012 survey revealed that 38% of the companies polled already saw climate change as an important success factor for their company. In 2010, 31% of the companies surveyed said that they ascribed a “high” to “very high importance” to climate change for corporate success.
Die von der Universität Oldenburg im Rahmen des Vorhabens ‚nordwest2050‘ durchgeführte Befragung von 4.000 Unternehmen der Metropolregion Bremen-Oldenburg im Nordwesten aus den Jahren 2010 und 2012 zeigt, dass die wirtschaftliche Bedeutung des Klimawandels wächst. Bei der Befragung 2012 gaben 38% der befragten Unternehmen an, dass sie dem Klimawandel eine „hohe“ bis „sehr hohe Bedeutung“ für den Unter-nehmenserfolg beimessen. 2010 waren es bereits 31% der Unternehmen, die im Klimawandel einen bedeutenden Erfolgsfaktor sahen.