The interaction of land use planning and legislation in stormwater management as part of urban development in Finland
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Auditorium IT116, Linnanmaa campus
Topic of the dissertation
The interaction of land use planning and legislation in stormwater management as part of urban development in Finland
Doctoral candidate
Master of Science Minna Mäki-Asiala
Faculty and unit
University of Oulu Graduate School, Faculty of Technology, Water, Energy and Environmental Engineering
Subject of study
Doctoral Degree Programme in Civil Engineering
Opponent
Title of Docent Teemu Kokkonen, Aalto University
Custos
Associate Professor Pekka Rossi, University of Oulu
How do zoning and legislation influence stormwater management in cities?
Finnish cities are becoming denser, and at the same time heavy rainfall is increasing due to climate change. This means that stormwater, rain and meltwater running off streets, yards and rooftops accumulate more easily in places where it can cause problems. When green spaces decrease and impermeable surfaces like asphalt increase, water can no longer soak into the ground as it used to. As a result, the risk of urban flooding grows.
This study examined how zoning and legislation affect the ability of cities to manage stormwater. The focus was on local detailed plans, since they determine how much an area contains buildings, streets and green spaces, and therefore how much stormwater can be generated.
The study approached the topic from three perspectives:
1. Planning – Stormwater amounts based on zoning plans
2. Design – Stormwater amounts generated by construction
3. Steering – Municipal practices in stormwater management
Over the past six decades, the amount of green space in the study area has clearly decreased, even though its importance has been increasingly emphasized in strategic goals. In practice, this has led to a significant increase in the amount of stormwater generated.
The study examined the area’s capacity to handle stormwater in two ways: through traditional manual calculations and through computer-based modelling. The results of the two methods differed, raising questions about the accuracy of the traditional design approach and highlighting the possible need to base stormwater dimensioning on actual regional rainfall data.
The study shows that effective stormwater management depends on how well the legal requirements are reflected in zoning and implementation. It also revealed some inconsistencies: municipalities often felt that the legal goals were well considered, but the analyzed zoning regulations did not always support this view. To help cities prepare for increasing rainfall and reduce flood risks, stormwater considerations should be more clearly integrated into all planning and zoning. This would help create more resilient urban environments that are better able to adapt to climate change.
This study examined how zoning and legislation affect the ability of cities to manage stormwater. The focus was on local detailed plans, since they determine how much an area contains buildings, streets and green spaces, and therefore how much stormwater can be generated.
The study approached the topic from three perspectives:
1. Planning – Stormwater amounts based on zoning plans
2. Design – Stormwater amounts generated by construction
3. Steering – Municipal practices in stormwater management
Over the past six decades, the amount of green space in the study area has clearly decreased, even though its importance has been increasingly emphasized in strategic goals. In practice, this has led to a significant increase in the amount of stormwater generated.
The study examined the area’s capacity to handle stormwater in two ways: through traditional manual calculations and through computer-based modelling. The results of the two methods differed, raising questions about the accuracy of the traditional design approach and highlighting the possible need to base stormwater dimensioning on actual regional rainfall data.
The study shows that effective stormwater management depends on how well the legal requirements are reflected in zoning and implementation. It also revealed some inconsistencies: municipalities often felt that the legal goals were well considered, but the analyzed zoning regulations did not always support this view. To help cities prepare for increasing rainfall and reduce flood risks, stormwater considerations should be more clearly integrated into all planning and zoning. This would help create more resilient urban environments that are better able to adapt to climate change.
Created 4.2.2026 | Updated 6.2.2026