Evolution of Edges and Porosity of Urban Blue Spaces: A Case Study of Gdańsk

Abstract

Current waterfront studies focus mainly on a land-based perspective, failing to include the water side. Water is, however, not just a resource for port and industrial purposes and an edge to the waterfront; it is also a feature of the waterfront and the complex relation between water and city. Thus, the article suggests that water-land edges need to be re-contextualised, taking into consideration also their shape, functionality, and evolution over time. This article therefore introduces the concept of urban blue spaces, that is, spaces that include at least one land-water edge, such as a shoreline or river edge. The types and character of these edges define the porosity of urban blue spaces: Spaces with easy connections, such as boulevards or parks, are highly porous, while fenced areas have low porosity. The research first analyses the existing literature on the spatial and functional characteristics of the land-water edge in port cities, and explores existing typologies of urban blue spaces. The results of this investigation are used to examine the most iconic urban blue space of Gdańsk, the Motława river, over the last 1000 years. The case study shows that the porosity of the Gdańsk urban blue space has been increasing over time, in line with its spatial and functional development from an undeveloped riverbank to a ‘gated’ port and industry area, to urban living spaces today. The article thus presents the whole breadth of urban blue spaces through the case study of the Motława river urban blue space. The spatial evolution of the urban blue space is depicted through the transformation of its land-water edge—from a natural sloping edge to the dominance of vertical edged structures or ones overhanging the surface of the water, to the emergence of spatially ‘blurred’ sloping, slanted, terraced, and floating structures, partially independent of the riverbank. The transformation of the structure of the Motława urban blue space edges increased its complexity over time, from a single-edge structure to a double and multiple-edged one.

Permeability of Waterfronts—Contemporary Approach in Designing Urban Blue Spaces

“…analysis of the location and urban context and collection of basic data on investments; -analysis of the features of the urban and architectural design affecting the land-water relationship, presented in graphic form (plan and cross-section) and qualitative description; -defining the type of land-water edge and the degree of its permeability using the existing typologies [2,35].…”

“…In relation to waterfronts the concept of "porosity" is defined as the discontinuity of boundaries of structures (e.g., walls, building frontages, rows of trees) surrounding and shaping the edges of urban blue public spaces [2]. While the "permeability" of the waterfront is understood as an ability of water to penetrate and flood the structure situated on the land-water edge, partially or fully, this results in the occurrence of a transition zone of a specific wide existing in between the two environments, instead of a sharp-contact land-water edge.…”

“…Waterfronts have always been the catchment area of human socio-cultural life in port cities and they were evolving towards increasing porosity of their edges [1,2]. Due to the constant urbanization pressure on the one hand and the process of port functions' of migration towards the sea on the other [3-7], waterfronts constantly evolve, being usually transformed into new, active centers of port cities [8][9][10][11][12][13][14][15][16].…”

“…In the case of operating port quays, where it is necessary to maintain the cargo handling function, the ordinate of the quay walls is usually raised to a safe height that is not any longer a subject to flooding. In case of public spaces on waterfronts however, it is possible to change the paradigm of shaping waterfronts towards increasing their permeability, and using water as an active part of the urban blue public spaces [1,2,[28][29][30][31][32][33][34][35][36][37]. Even the flood protection infrastructure might be planned as being multifunctional and integrated with the design of public space [33,34].…”

“…The work examines the spatial features of the urban blue public spaces located on these redesigned waterfronts. The concept of urban blue public space is understood here as a commonly accessible area consisting of both water and land and including therefore at least one land-water edge [2].…”