The Historic Urban Landscape (HUL) approach promoted by UNESCO calls for integrating natural and cultural heritage, yet its empirical application in urban planning remains limited, especially in Latin American cities. This study addresses that gap by proposing a multidimensional mathematical model to quantify environmental sustainability in the Ingachaca Urban Action Unit in Cuenca, Ecuador. The area is a transitional landscape combining vernacular architecture, the Tomebamba River riparian corridor, and the Pumapungo archaeological complex.
A Composite Environmental Sustainability Index was developed using the Analytic Hierarchy Process (AHP) based on expert consensus. Seven indicators were standardized on a 0–1 scale using satellite imagery and in situ sensors: soil permeability, green area per capita, vegetation index (NDVI), biological diversity (Shannon Index), water quality (WQI), air quality (settleable dust and combustion gases), and acoustic pollution.
The resulting global index reached 0.593, indicating moderate environmental sustainability while revealing strong ecological polarization. On the positive side, the landscape structure shows high biophysical resilience, supported by 78.15 m² of green space per capita, 71.3% permeable soil, robust vegetation coverage, and acceptable river water quality (WQI = 67.55). These conditions provide a solid ecological base consistent with HUL principles.
However, this potential is significantly undermined by intense external urban pressures. The most critical impacts are extreme acoustic pollution, with average daily noise levels of 118 dB and peaks above 130 dB, and sustained atmospheric degradation driven by heavy vehicular traffic.
The proposed AHP-based model supports strategic planning by integrating Nature-based Solutions (NbS) with heritage conservation. It quantitatively demonstrates how blue–green infrastructure can mitigate environmental stressors while protecting vernacular and archaeological values. Replicable across historic urban centers, the methodology reframes heritage landscapes as resilient socio-ecological systems where ecological restoration and cultural preservation jointly enable sustainable, healthy urban living.
