Stormflow against streamflow – Can LID-provided storage capacity ensure performance efficiency and maintenance of pre-development flow regime?

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-11
Major/Subject
Mcode
Degree programme
Language
en
Pages
Series
Journal of Hydrology, Volume 602
Abstract
The goal of Low Impact Development (LID) is to restore and maintain the pre-development flow regime. The static storage capacity, which is often used as a parameter in LID designs, provides the maximum capacity of an LID type and is easily quantifiable already at the design phase. However, the static storage approach does not consider the inter-event recovery of storage capacity by infiltration and evapotranspiration. This study investigated dynamic storage capacities of three stormwater management designs with increasing proportions of LID units on a 1.2 ha urban residential block in Southern Finland, to compare their cost-efficiency, as well as their potential in restoring the pre-development flow regime. The cost-efficiency of LID designs was assessed based on their ability to contribute to water losses, and on the additional construction costs required when comparing them to conventional solutions (e.g. asphalt replaced with permeable pavement). The design with a small storage capacity and a large captureratio, i.e., the ratio of contributing area to LID area, was the least efficient albeit its small construction cost. The design with an appropriate balance between the capture ratio and the LID provided storage capacity was the most efficient option. In assessing the potential of stormwater designs in restoring the pre-development flow regime, the sum of infiltration and flow in storm sewer networks was more representative of the catchment total runoff than flow alone. Finally, an extensive simulation of a large set of differently placed LID units proved useful in a priori identification of the most influential units in the treatment train.
Description
Funding Information: This work was funded by Ministry of Agriculture and Forestry, Finland; Schlumberger Foundation Faculty for the Future, Academy of Finland (no 326787, WaterWorks2017 ERA-NET Cofund) and Maa- ja vesitekniikan Tuki ry. The study was part of the UrbanStormwaterRisk and EviBAN (Evidence based assessment of NWRM for sustainable water management) projects. Elisa Lähde, a landscape architect, designed the alternative stormwater management designs assessed in this study. The rainfall data for design simulations came from a rain gauge operated by the City of Turku. The streamflow data for rural reference watershed (Savijoki) and semi-urban reference watershed (Kuninkoja) came from monitoring stations maintained by the Finnish Environment Institute (SYKE) and Turku University of Applied Sciences (TUAS), respectively. Funding Information: This work was funded by Ministry of Agriculture and Forestry, Finland; Schlumberger Foundation Faculty for the Future, Academy of Finland (no 326787, WaterWorks2017 ERA-NET Cofund) and Maa- ja vesitekniikan Tuki ry. The study was part of the UrbanStormwaterRisk and EviBAN (Evidence based assessment of NWRM for sustainable water management) projects. Elisa Lähde, a landscape architect, designed the alternative stormwater management designs assessed in this study. The rainfall data for design simulations came from a rain gauge operated by the City of Turku. The streamflow data for rural reference watershed (Savijoki) and semi-urban reference watershed (Kuninkoja) came from monitoring stations maintained by the Finnish Environment Institute (SYKE) and Turku University of Applied Sciences (TUAS), respectively. Publisher Copyright: © 2021 The Author(s)
Keywords
Performance efficiency, Pre-development flow regime, Storage capacity
Other note
Citation
Khadka , A , Kokkonen , T , Koivusalo , H , Niemi , T J , Leskinen , P & Körber , J H 2021 , ' Stormflow against streamflow – Can LID-provided storage capacity ensure performance efficiency and maintenance of pre-development flow regime? ' , Journal of Hydrology , vol. 602 , 126768 . https://doi.org/10.1016/j.jhydrol.2021.126768