Browsing by Author "Siren, Pirjo"

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    Olari, the basic improvement plans of the environment with aid of communicative planningmethods
    (1998) Siren, Pirjo; Arkkitehtiosasto; Teknillinen korkeakoulu; Helsinki University of Technology; Rautamäki, Maija
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    River restoration in Espoo - Developing and applying a prioritization method
    (2013) Mäkinen, Sofia; Siren, Pirjo; Yhdyskunta- ja ympäristötekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Järvelä, Juha
    Rivers and streams are one of the most threatened biotypes today, and there is a growing investment for restoring these biotypes. When there are many restoration sites and limited resources, the need for prioritization grows. The purpose of this thesis was to create a prioritization method suitable for the city of Espoo, and used for prioritizing 25 river sites. The sites were chosen by the Centre for Economic Development, Transport and the Environment (Uusimaa) together with the city of Espoo, and were considered to be in need of restoration. The sites are located in Espoonjoki and Mankinjoki catchment areas. Ten assessment criteria were chosen for the prioritization and the scoring of the restoration sites. The assessment criteria were the ecological status of the river, type of surface water, spawning area, migration barriers and connectivity to the sea, river system class, water-and nature values, recreational use, historical-and cultural values, land ownership and zoning. To fill the assessment criteria, a background research was made of all the restoration sites. The results from the background research are shown in the appendix of this work. The results and information can be used for further restoration planning. The prioritization was based on a multicriteria decision analysis method, the additive preference model. Based on the model, all criteria were given a weight to describe their importance with relation to the other criteria. The site prioritization was evaluated through two different options; in the first option (1) all ten criteria were given separate weights, while in the second option (2) the criteria were divided under five main criteria which were weighted. After comparing the two options, the final prioritization method was chosen to be based on the second weighting option. After ranking the restoration sites, the sites were still evaluated by (based on?) their location and uncertainties. High priority sites were those sites that were given high points at many different criteria. The prioritization method used in this work is functional and transparent; it is easily adapted and can therefore be used outside Espoo as well.
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    Stormwater management plan for Myllypuro in Northern Espoo
    (2013) Zein, Roni; Rauhala, Ésa; Siren, Pirjo; Yhdyskunta- ja ympäristötekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Koivusalo, Harri
    Espoo is a fast growing and dynamic city. Due to the increase of built and impervious surfaces the management of urban runoff and storm water has become an annual problem in many urban areas of Espoo. This work is focused on resolving one of these problems in the Northern districts of Espoo, Niipperi. Niipperi is exposed to floods during heavy rain events in summer time. During these events the flow rapidly increases in Myllypuro stream that flows across Niipperi. This raises water level considerably due to the insufficient transmission capacity of the riverbed and causes damage to the surrounding properties. Espoo tried to solve the flood problem in 2006 by planning a flood levee to Niipperinportti but the ecological conditions of Myllypuro prevented the completion of the project. The flood management solution developed in this work should take into consideration environmental aspects as well as bringing immediate relief to the flood problems in the area. The management solution should also have reasonable cost. Based on background studies and previous plans, a retention basin placed one kilometre upstream of Niipperinportti would fulfil the requirements mentioned above. The retention basin would be placed apart from the riverbed and therefore would not affect its ecosystem. The 2700 m2 volume of the basin would eliminate floods that occur due to rain events that occur once every 20 years. The cost of the project stays reasonable and at best the retention basin could create new biotopes for several animal species as birds and amphibians.