An Operational Model for Water-Efficient Sustainable Landscape Design Using a Xeriscaping Approach in Cold and Dry Mountain Climates: A Case Study of Sanandaj

In mountainous ecosystems with cold, arid climates in western Iran, the sustainability of human-made landscapes faces complex challenges stemming from hydrological stress, limited water resources, and geomorphological instability. This study aimed to develop a practical model for xeriscaping adapted to the climatic constraints, rugged topography, and ecological characteristics of mountainous regions, using the city of Sanandaj as a case study. Drawing on the principles of landscape ecology, environmental hydrology, and natural engineering, and employing a qualitative research approach combined with the Delphi technique, the study identified the key components of sustainable landscape design in cold, arid mountainous climates. The findings showed that achieving ecological sustainability and reducing dependence on conventional water resources requires the integration of five fundamental strategies. First, improving the hydrological properties of soil through texture amendment, increased organic matter, and permeable depressions to enhance moisture retention and control surface runoff. Second, integrated water resource management emphasizing the intelligent storage and conveyance of precipitation and snowmelt into subsurface reservoirs and infiltration basins. Third, microclimate engineering through windbreak belts, multilayer shading, and locally sourced, high-thermal-capacity materials to moderate temperature fluctuations and reduce thermal stress. Fourth, the use of alternative water sources, including treated greywater and atmospheric water harvesting systems. Fifth, adaptive planting design based on native species resistant to cold and drought stress, with physiological traits such as deep root systems, thick cuticles, water-use efficiency, and high osmotic tolerance. Overall, by integrating knowledge from geomorphology, landscape hydrology, and plant ecology, the proposed model offers a scientific and practical framework for reducing water consumption, enhancing ecosystem resilience, and promoting environmental sustainability in mountainous landscapes. It can serve as a basis for planning and designing sustainable landscapes in cold, arid regions.
 
Extended Abstract
 
Introduction
Within the contemporary landscape design paradigm, the shift from purely ornamental approaches toward ecological sustainability has underscored the growing need to reduce resource consumption, particularly water use. Freshwater scarcity, which is particularly acute in arid and semi-arid regions, has been intensified by urban population growth, economic development, and climate change, posing increasing challenges to the sustainability of urban green spaces. Under these conditions, expanding green-space coverage without considering water-resource availability may place additional pressure on already limited supplies. Accordingly, the selection of climate-adapted plant species, optimization of planting patterns, and adoption of water-efficient landscape strategies have become increasingly important. This challenge is particularly complex in the cold, dry mountainous climate of western Iran due to pronounced temperature fluctuations, seasonal frost, limited water availability, steep topography, and unfavorable soil conditions. Despite the growing adoption of xeriscaping and water-efficient landscape design, many existing models have been developed primarily for hot-arid or temperate climates and therefore have limited applicability to the distinctive environmental conditions of mountainous regions in western Iran. Against this background, this study aims to develop a localized and operational framework for xeriscape design under cold, dry mountainous conditions, using Sanandaj as a case study. The study examines and prioritizes key components for reducing landscape water consumption, including the selection of climate-adapted plant species, soil modification, sustainable management of surface water, and microclimate optimization, with the aim of providing a practical framework for sustainable, water-efficient, and climate-resilient landscape design adapted to the environmental characteristics of cold, dry mountainous regions.
 
Methodology
Data collection and analysis were conducted using a qualitative approach and the Delphi technique. Accordingly, 15 experts in landscape design, climatology, architecture, civil engineering, and environmental planning were purposively selected. Following the assessment and confirmation of the face and content validity of the questionnaire by six experts, the Delphi process was conducted in two rounds from May to November 2025. In the first round, open-ended questions and qualitative content analysis were used to identify challenges, design principles, and potential strategies related to xeriscaping in cold and dry mountainous climates and to extract the preliminary indicators. In the second round, the identified indicators were evaluated and prioritized using a three-point Likert scale based on their importance, feasibility, ecological effectiveness, and potential for localization. Finally, the data were examined through qualitative-interpretive analysis and descriptive statistics using Microsoft Excel, and the selected indicators were determined based on their frequency of occurrence and the level of agreement among the experts. The resulting findings were used to develop an operational framework for “mountain xeriscaping” aimed at supporting sustainable and water-efficient landscape design in cold and dry mountainous regions.
 
Results and Discussion
The results of the two rounds of the Delphi questionnaire indicated that water-saving strategies in xeriscape design for cold and dry mountainous regions can be classified into five main dimensions: increasing soil water-retention capacity; managing and storing rainwater and snowmelt; microclimate engineering; using alternative water sources and water recycling; and selecting planting schemes adapted to climatic and topographic conditions. In the first round, experts’ suggestions concerning irrigation methods, water-management infrastructure, water collection and storage systems, and plant characteristics were identified, while the second round focused on determining the indicators with the highest frequency of occurrence and level of agreement. Based on the experts’ consensus, soil modification, efficient irrigation systems, the creation of water-infiltration depressions and rain gardens, subsurface water storage, runoff and snowmelt management, the use of windbreaks and shade structures, and the selection of native species tolerant of drought and frost were identified as key strategies for reducing landscape water requirements. The findings further indicated that, in cold and dry mountainous climates, particular attention to snowmelt water management and the simultaneous consideration of microclimatic conditions and frost, alongside conventional xeriscape strategies, are especially important and can provide a basis for developing a locally adapted landscape design framework consistent with the environmental conditions of these regions.
 
Conclusion
The findings showed that achieving sustainable landscape design in cold and dry mountainous climates requires an integrated approach that is adapted to climatic and geomorphological characteristics and water resource limitations. The main contribution of the study was the development of a “Mountain Xeriscape” framework based on soil modification, surface water and snowmelt management, microclimate engineering, and the selection of resilient native plant species. Pilot implementation of this framework in Sanandaj’s green spaces, the use of native low-water-demand species, and the development of greywater recycling are recommended. The main limitations of the study included the limited number of experts, the lack of field validation of the proposed framework, and the focus on Sanandaj, highlighting the need for further investigation in other mountainous regions.