Achieving Urban Stormwater Mitigation Goals on Different Land Parcels with a Capacity Trading Approach

Abstract

Building Green Infrastructures (GIs) to reduce stormwater runoff has been recognized as an effective approach to mitigate the negative impact of urban sprawl. Due to the significant differences in urban land use, some Land Parcels (LPs) may have difficulty in building enough GIs to meet stormwater mitigation goals. In this paper, we proposed a Capacity Trading (CT) approach that allows some LPs to trade their extra runoff retention capacities with LPs that have building difficulties, so that they can jointly reach the overall mitigation goal together. The rationale behind CT is that, to avoid potential penalties, it may be more economical for some LPs to ‘buy’ credit rather than to ‘build’ GIs. A case study was used to demonstrate CT operations for two trading scales: (1) CT within neighboring LPs (i.e., CT-1), and (2) CT within 20 m-radius LPs (i.e., CT-2). A GI implementation baseline intensity was set up firstly by treating the whole study area as one entity to reach a specified stormwater runoff control target; individual LPs were then examined for their GI building capacities, which may be deficit or surplus against the target. Results showed that the number and area of deficit LPs were reduced significantly through either CT scales; the number of deficit LPs was reduced from 139 to 97 with CT-1 and 78 with CT-2, and the deficit area was reduced from 649 ha to 558 with CT-1 and 478 ha with CT-2, respectively. The proposed method assumes LPs as the basic planning unit and encourages some stakeholders to maximize their GI building potential to compensate for those with disadvantages. The economic incentives for conducting CT among different LPs in urban area can help achieve stormwater mitigation goals more economically and flexibly. Some coordination among LPs in GI implementation is necessary, which presents both opportunities and challenges for city management.

Management of Urban Stormwater at Block-Level (MUST-B): A New Approach for Potential Analysis of Decentralized Stormwater Management Systems

“…There are similar approaches for modeling and simulation of LIDs reported by Liu et al [41] and Xu et al [42], where the study area is divided in similar functional units. However, while Liu et al [41] focused on using only roof greening on available roof area to mitigate the stormwater runoff, Xu et al [42] developed a method to quantify the capacity of transporting runoff between the blocks. Transporting the runoff between blocks was not an option in this study, due to the high costs involved in such options.…”

Economic Incentives in Stormwater Management: A Study of Practice Gaps in Poland

“…Conducted research shows that in a situation where on-site retention is technically unfeasible or very expensive, it is rational to create the possibility of fulfilling the obligation by off-site retention by purchasing "credits" from others who have the opportunity to make an investment with a capacity greater than required [13,14,16]. A trading system allows the minimization of GI implementation costs and achievement of higher quantitative effects in terms of retention [14,17,18]. Stormwater trading markets are not yet fully developed in practice [9].…”