Introduction

With the rapid advancement of urbanization, urban water environments are facing unprecedented challenges (Chen et al. 2015). The continuous expansion of impervious surfaces has disrupted the natural water cycle, resulting in rapid stormwater runoff, increased frequency of urban flooding, and reduced groundwater recharge. At the same time, worsening water pollution and the intensifying urban heat island effect further highlight the limitations of traditional urban planning and design in adapting to hydrological systems. Climate change also exacerbates these issues, with increasing frequency and intensity of extreme weather events such as heavy rainfall and droughts, placing immense pressure on cities’ capacities for water storage, drainage, purification, and ecological restoration.

In this context, Water Sensitive Urban Design (WSUD) has emerged as a widely recognized approach to sustainable urban development. Closely related to the concept of Low Impact Development (LID), WSUD emphasizes mimicking the natural water cycle and enhancing urban resilience to water-related challenges. It aims to integrate ecological and social functions by treating water as an integral part of the urban system and actively managing its collection, transport, treatment, and storage (Wong 2006).

Remote sensing, with its advantages of a macro perspective, continuous observation, and high spatial resolution, provides valuable, cross-scale support throughout the WSUD process. It can identify key features such as impervious surfaces, water bodies, and green space coverage during the early stages of urban planning and design, offering scientific guidance for the layout of blue and green infrastructure. It also enables dynamic monitoring of urban heat, water quality, vegetation health, and flood risk. Remote sensing makes “invisible processes” visible, helping urban designers and the public intuitively understand the spatial logic and effectiveness of stormwater management strategies.

Water-sensitive urban design

“A water sensitive city (WSC) will be a collection of interconnected water sensitive precincts. In each one, site-specific plans will be developed to respond to local opportunities and constraints. These precincts will: efficiently use the diversity of water resources available; enhance and protect the health of urban and natural waterways; and mitigate against flood risk and damage. Public spaces are green infrastructure that harvest, clean and recycle water, increase biodiversity, support carbon sequestration and reduce urban heat island effects.”      
——Tony H F Wong, Professor of Sustainable Development, Monash University

To bring the vision of WSC into practice, WSUD has emerged as a core strategy. WSUD encompasses a set of strategies aimed at sustainable water management, enabling the development sector, local governments, and communities to create more liveable cities with thriving, healthy waterways (Healthy Land & Water, n.d.).  WSUD emphasizes the integration of planning and management practices in urban water systems (Joint Steering Committee for Water Sensitive Cities 2009).

Planning practices in WSUD are planning methods used to guide how land is assessed, planned, and designed to support sustainable water management (Kuller et al. 2017). They start with understanding the natural and physical characteristics of a site, using that knowledge to shape development in ways that protect the environment and manage water wisely, which can be applied at both strategic (big-picture ) and detailed (design) levels—for example, deciding where to build, where to preserve green space, or how to design roads and buildings to conserve water (Joint Steering Committee for Water Sensitive Cities 2009). These practices help to the development of urban layouts that incorporate stormwater management systems, preserve natural landscapes, and integrate water-efficient features into streets, residential areas, and public spaces. 

Management practices cover the full process of stormwater management, including collection, transport, treatment, storage, infiltration, and evapotranspiration (United States Environmental Protection Agency 2021). Figure 1 shows how widespread implementation of WSUD elements—such as stormwater harvesting, bio-retention systems, infiltration technologies, and increased vegetation— can reduce runoff and enhance sustainability (Coutts et al. 2012). At the micro-scale, WSUD features such as rain gardens, swales, tree pits, porous pavements, and green roofs promote infiltration and evapotranspiration, thereby mitigating runoff and supporting localized cooling. Enhanced irrigation with harvested stormwater further sustains vegetation and reinforces these processes. At the local scale, these effects accumulate to provide broader urban cooling, especially when integrated with green infrastructure like trees and irrigated open spaces.        
 

In summary, WSUD is not just a set of scattered projects, it’s a holistic urban design approach that blends ecology, landscape, hydrology. It promotes a shift from “drainage-focused” to “water-sensitive” cities, treating rainwater as a resource, not a burden.

Remote sensing in WSUD

Planning practices

• Urban space and land use monitoring

Urban layout affects runoff paths and infrastructure planning. Remote sensing provides high-resolution land cover data to identify impervious surfaces, building density, roads, and green spaces. Combined with Geographic Information System (GIS), it helps locate areas lacking green space or with high runoff risk, supporting green and blue infrastructure planning and land use optimization. For example, Weng (2001) developed an integrated methodology combining remote sensing and GIS to assess the hydrological impacts of urban growth. Using Landsat Thematic Mapper data and the runoff model (Figure 2), the study quantified how land-cover changes increased surface runoff, revealing that areas with more intense urbanization experienced greater runoff and flood risk due to reduced storage capacity and higher runoff coefficients.       
 

• Green space system monitoring

Urban green spaces help manage stormwater and reduce pollution. Vegetation indices, such as the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI), derived from remote sensing data, are used to monitor the health and changes of green spaces. This supports the maintenance and planning of rain gardens, wetlands, and other green infrastructure. Conley et al. (2022)used Landsat-derived NDVI data to examine 372 urbanized watersheds, assessing the impact of urban greenness and green stormwater infrastructure (GSI) on hydrology. They found that Urban greenness had significant influences on downstream flow responses, highlighting the value of remote sensing in evaluating green infrastructure performance in WSUD.

• Urban heat island detection and climate regulation

Thermal infrared data from remote sensing reveals surface temperatures and heat island hotspots (Figure 3). By analysing links between heat, impervious surfaces, vegetation, and water, planners can add cooling features like greenery and water bodies to improve urban comfort. Zhao et al. (2025). provide a comprehensive review of remote sensing methods for monitoring urban heat island effects, highlighting how thermal infrared data, combined with indicators like impervious surfaces, vegetation, and water bodies, can effectively identify heat hotspots and guide the planning of cooling interventions such as green and blue infrastructure.       
 

Management practices

• Hydrological modelling and flood risk management

Remote sensing offers key inputs like digital elevation models (DEM), land use, and soil moisture for urban hydrological models. When combined with rainfall and flood records, the data enables flood simulation and risk mapping. This supports identifying of drainage issues, prioritizing maintenance of stormwater infrastructure, and planning emergency response strategies for flood-prone areas. The web-based urban water cycle modelling system developed by Mair et al. (2014) can integrate terrain and land use information obtained from remote sensing. It allows users to set surface parameters through a map interface, automatically runs hydrological models, and assesses flood risks, thereby providing data-driven decision support for urban drainage, stormwater management, and adaptive flood management (Figure 4).       
 

• Water body mapping and water quality monitoring

Indices such as the Normalized Difference Water Index (NDWI) and the Modified Normalized Difference Water Index (MNDWI) are useful for detecting water bodies and monitoring their changes over time. With multispectral or hyperspectral data, remote sensing can estimate water quality indicators like turbidity, dissolved organic carbon (DOC) and chlorophyll-a (Figure 5). These capabilities ensure continuous monitoring of urban water bodies, early detection of pollution events, and evaluation of the effectiveness of water-sensitive interventions such as constructed wetlands or ecological shorelines. This supports WSUD goals like ecological shorelines and clean, accessible urban waters.       
 

Overall, remote sensing supports the entire WSUD process by enabling both planning and management practices. In the early stages, it informs planning practices such as spatial identification of impervious surfaces, green space allocation, and infrastructure siting. As projects progress, it contributes to management practices including implementation monitoring, flood risk assessment, and performance evaluation of green and blue infrastructure. This integrated use of remote sensing forms a spatial, dynamic, and science-based approach to managing urban water systems. The main satellite technologies involved are summarized in Table 1.

*Note: Abbreviations at first occurrence in the table (listed alphabetically): AMSR-E=Advanced Microwave Scanning Radiometer for EOS; ASI = Agenzia Spaziale Italiana; CNES=Centre national d'études spatiales; CNSA = China National Space Administration; CSA= Canadian Space Agency; DLR = Deutsches Zentrum für Luft- und Raumfahrt; ECOSTRESS=ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station; EnMAP = Environmental Mapping and Analysis Program; ESA = European Space Agency; JAXA=Japan Aerospace Exploration Agency; GEDI = Global Ecosystem Dynamics Investigation; GFZ=German Research Centre for Geosciences; HY-2A/B = Haiyang-2A/B; HySIS = Hyperspectral Imaging Satellite; ICESat-2 = Ice, Cloud, and land Elevation Satellite-2; ISRO = Indian Space Research Organisation; Lidar = Light Detection and Ranging; LVIS=Land, Vegetation, and Ice Sensor; MODIS=Moderate Resolution Imaging Spectroradiometer, NASA = National Aeronautics and Space Administration; NOAA=National Oceanic and Atmospheric Administration; PRISMA= Hyperspectral Precursor of the Application Mission; SAR = Synthetic Aperture Radar; SMAP=Soil Moisture Active Passive; SMOS = Soil Moisture and Ocean Salinity; SPOT = Satellite Pour l’Observation de la Terre; USGS = United States Geological Survey; VIIRS=Visible Infrared Imaging Radiometer Suite

Case study: remote sensing supporting WSUD in Australia

Australia is widely recognized as one of the birthplaces of the WSUD concept. The term was first coined by Mouritz in 1992, and the first formal WSUD guidelines were published by the Western Australian Government in 1994 (Radcliffe 2018; Whelans Consultants. et al. 1994).  In the years that followed, the South Eastern Councils WSUD Guidelines played a key role in promoting consistent water-sensitive urban design practices across Melbourne’s southeastern municipalities (Parsons Brinckerhoff 2013). These efforts were supported by early on-ground implementations in cities like Melbourne and regional collaborations such as the Inner Melbourne Action Plan (IMAP), which helped shape model guidelines (Stonnington City Council 2009). To further consolidate and improve access to these resources, the Clearwater WSUD Guidelines Tool was developed, offering a structured platform for navigating guidance across asset types and project stages (Clearwater 2018).

As the WSUD concept matured, remote sensing technologies began playing a key role in supporting evidence-based planning and performance evaluation. The national Digital Earth Australia (DEA) program—established by the Australian Government—provides analysis-ready satellite data to planners, researchers, and policymakers (FrontierSI 2022). By leveraging EO data from satellites such as Landsat and Sentinel, DEA enables the identification of urban heat islands, monitoring of impervious surfaces, and assessment of vegetation and water distribution—critical inputs for WSUD planning.

This integration of EO data into WSUD practice is evident in several research and planning frameworks. For example, an Infill Performance Evaluation Framework developed by Cooperative Research Centre for Water Sensitive Cities (CRCWSC) uses remote sensing datasets from Geoscape Australia, a government-owned provider of national geospatial data, to identify impervious surfaces and estimate Total Impervious Area (TIA), which feeds into water balance models for evaluating WSUD effectiveness (Renouf et al. 2020). In a related study, Mitchell et al. (2008). compared two water balance models—Aquacycle and SUES—and found that incorporating seasonal vegetation changes, measured via Leaf Area Index (LAI) from remote sensing, improved model accuracy, especially for evapotranspiration estimates.

Further demonstrating the value of satellite data in urban flood planning, the SmartSat CRC has developed advanced flood monitoring capabilities using SAR satellite data, including NovaSAR and Sentinel. The project has been tested in real-world flood events in southeast Australia and has provided flood maps to relevant government agencies and end-users to support disaster response and planning (SmartSat CRC 2025). Kelly et al. (2023) applied satellite-derived land cover data in the rapidly urbanizing Hawkesbury–Nepean catchment to model spatial flood risk. Their study showed how remote sensing enhances the resolution and reliability of flood risk assessments, helping urban planners identify vulnerable areas and prioritize WSUD interventions.

Conclusion

WSUD represents a transformative approach to urban planning that integrates ecological, hydrological, and social considerations to create more resilient and liveable cities. By providing high-resolution, spatially continuous, and temporally consistent data, remote sensing enables informed decision-making across both planning and management stages of urban water systems. From identifying impervious surfaces and green space distribution to monitoring urban heat islands, flood risks, and water quality, remote sensing technologies offer powerful tools for evidence-based design and adaptive management. This makes the vision of water-sensitive urban development not just a long-term goal, but an actionable and adaptive process supported by real-time monitoring and evaluation.