From diagnosis to action: A phased in-situ upgrade framework for informal settlements in Taiz, Yemen

Informal settlements in conflict-affected cities are often studied through diagnostic accounts of deprivation, yet fewer studies explain how such evidence can be translated into spatially explicit and phased upgrading actions. This paper addresses this gap through the case of Kalabah, a consolidated informal settlement within the urban fabric of Taiz, Yemen. Building on previous diagnostic research, field mapping, existing-condition panels, satellite-based spatial referencing, AutoCAD drawings, and flexible planning standards, the study applies a four-stage conceptual framework (evidence, indicators, integrated interventions, and spatial priorities with phasing) and documents how it was operationalized for phased in-situ upgrading in an in-depth single-case application. The analysis first identifies the main spatial and service constraints in Kalabah, including weak land-use organization, narrow and irregular access, fragmented water provision, inadequate sewerage and drainage, unmanaged solid waste, fragile housing conditions, and limited open-space structure. It then translates these constraints into an integrated planning proposal that combines land-use restructuring, mobility improvement, infrastructure upgrading, residential models, commercial and mixed-use components, landscape/open-space interventions, and sector-based implementation phasing. The findings show that Kalabah should not be approached as a temporary urban fragment to be cleared, but as an existing urban fabric requiring gradual reorganization and service integration. The contribution of the study lies not in proposing in-situ upgrading itself, but in a transparent, traceable record of how diagnostic evidence was translated into indicators, integrated interventions, and spatially prioritized implementation phases while reducing reliance on large-scale clearance and external relocation. The Kalabah case may inform planning in Taiz and comparable conflict-affected cities as a documented example to test and adapt, not as a validated or directly replicable model; implementation would in any case require detailed surveys, engineering design, cost estimation, institutional coordination, and community participation.