Hållbar Dagvattenhantering på Kvartersmark : En utvärdering av hur väl den planerade dagvattenhanteringen fungerar i verkligheten

Sammanfattning: Storm water management in residential areas is facing tough challenges. Climate change, with its altered precipitation patterns, in combination with an increasing development rate, results in higher risk of flooding with its complications. EU-Water Framework Directive (WFD) and its environmental quality standards, set to achieve good chemical and biological status in all waters, got a more strict interpretation after the implementation of the ruling of Weserdomen. This means that no activity is allowed that cannot prove not to endanger prevailing environmental quality standards. This complicates the planning process and infrastructure development since some form of WFD assessment needs to be performed.   This master´s thesis is of importance since it identifies common occurring problems within the planning- and construction process and highlights ways to achieve a more sustainable storm water management, where environmental quality standards are not jeopardized, in the future. An evaluation is performed in terms of interviews, a literature review and by using a storm water model called StormTac applied on two case studies. Results of this thesis show that lack of communication, vague directives, inadequate design and maintenance of storm water facilities are reasons that a sustainable storm water management is not achieved.   Results from modeling the storm water situation prior to construction of the residential areas were set as benchmarks, which were not to be exceeded by results from modeling areas after construction. The purpose of this was to not endanger the current storm water state and thereby not risk violating prevailing environmental quality standards. The result from modeling the storm water situation after construction shows that both case studies exceed the flow and pollution load benchmarks. Because of this, solutions to the current storm water situation was created and modeled to achieve the study aim.   StormTac can be applied as a tool for comparison of flow and pollution load prior to and after construction, given that the same land uses are used in both cases. Land use choices should be evaluated and the degree of uncertainty should be considered when interpreting the results.