A parametric integrated workflow to assess multi-domain heat- and flood-related performance of small outdoor urban spaces in a changing climate: A case study in the mediterranean region

Abstract

Urban areas face increasing exposure to climate-induced hazards, including extreme heat and urban flooding, challenges exacerbated by limited green and blue areas. This study presents an integrated parametric workflow for the preliminary evaluation of multi-domain performance of small outdoor spaces, at early design stages, as adaptive interventions for mitigating these issues at the neighborhood scale. Using parametric modelling in Grasshopper with Ladybug Tools and Kangaroo plugins, the novel methodology assesses thermal comfort and surface runoff dynamics in a heat- and flood-prone outdoor space. Thermal stress was evaluated using Ladybug tools via the Universal Thermal Climate Index and the Mediterranean Outdoor Comfort Index, and compared with ENVI-met simulations results to test the reliability of the proposed workflow. Results highlighted significant thermal discomfort during peak summer hours, especially in unshaded areas. Irrigated vegetation, including trees and grass, effectively reduced heat stress, even if in some regions, due to water scarcity, irrigation entails trade-offs. Surface runoff analyses, combining qualitative and quantitative computations, revealed green spaces’ potential to mitigate water accumulation while exposing design inefficiencies, such as impermeable borders restricting infiltration. The findings underscore the critical role of small outdoor urban spaces in enhancing urban resilience. Key design strategies include increasing permeability to reduce runoff, maintaining greenery with irrigation, and integrating shaded elements to improve thermal comfort. The proposed workflow allows rapid scenario-based testing of design solutions during early planning stages, offering practitioners a preliminary tool for adaptive urban design. By addressing hydrological and thermal challenges within a unified workflow, the study highlights the co-benefits of small-scale green infrastructure, advancing climate adaptation and resilience in compact urban settings while promoting equitable and sustainable cities.