Characteristics of Decision-Making Regarding Stormwater Management and Blue–Green Infrastructure in Large Development Plans in Norway

Introduction

Blue–Green Infrastructure (BGI) is interconnected aquatic green spaces and designed green spaces to combat climate change. The collective effectiveness of BGI measures at catchment scale has been widely demonstrated. Connecting BGI at the catchment/district scale to obtain a large capacity. In stormwater management, where capacity is increased through such connections, detailed analysis of floodways, capacity, etc., is important. This presentation demonstrates the characteristics of decision-making regarding stormwater management that ensure the systematic integration of facilities in six large development plans in Stavanger.

Methods

‘’Opinions in the start’’, ‘’drainage plans’’, and ‘’final regulations regarding stormwater management’’ are summarized, and the interrelationships between the contents are categorized.　Interrelationships are examined in which the contents of discussions and considerations "provide a direction for planning and analysis," "provide a basis for methods and requirements," or "become the contents of regulations as they are."

Results

There were common trends such as discussion of BGI in an early stage, analysis and consideration based on drainage plans, and a process of indicating the degree of BGI introduction at an early planning stage and requesting further analysis and consideration from the developer. There was a common trend that the municipality performed analysis and consideration to the extent that it could indicate main stormwater systems, requests related to specific developments, and specific problems, and the developer performed the remaining work.

Conclusions

The municipality clarifies the overall capacity and system through district-scale analysis. Within that, it integrates BGI for private properties, privately developed public facilities, private shared facilities, and BGI developed by the municipality. To achieve this, there is a systematic approach of discussing and clarifying the degree of BGI introduction and division of tasks based on analysis from an early planning stage, ensuring consistency from the district scale to the site scale.