Advancing city planning with impenetrable land monitoring

Advancing city planning with impenetrable land monitoring

19 Apr 2024

Since the turn of the 21st century, dynamic urban changes have been taking place at an unprecedented level. The percentage of word’s population living in urban areas has doubled in only 50 years, marking a relevant increase of urbanisation practices. These modifications come with significant environmental challenges, for instance, the increase of impervious or impenetrable surfaces.

Basics of imperviousness concept and its importance for urban planning techniques

Impervious surfaces are defined as areas that prevent or impede the infiltration of water into the soil. For example, paved roads, sidewalks, and buildings represent such surfaces as opposed to dirt roads or green areas. The increase in the surface of impenetrable areas is known to result in substantial repercussions such as causing degradation of stream hydrology*, increasing the probability of urban flooding, and elevating air temperatures through the urban heat island effect. To comprehend the impacts of these urban transformations, it is crucial to monitor and analyse how cities evolve. 

Extensive research has been conducted to improve the monitoring of impermeable areas, however, further improvements are necessary. This is where EO in general, and Copernicus in particular, can play an important role. 

Innovation behind the “Continuous imperviousness monitoring” prototype

The new prototype candidate called “Continuous imperviousness monitoring aims to be integrated into the Copernicus Land Monitoring Service (CLMS) . While the already existing High Resolution Layer Imperviousness product offered by the Copernicus programme is already providing information at 10m spatial resolution every three years, the EvoLand prototype works towards achieving a finer 5m spatial resolution by using the Sentinel-2 super resolution. Besides, it seeks to upgrade the temporal resolution through a flexible monitoring cycle, transitioning from a three-year interval to, ideally, monthly assessments. Finally, feasibility and potential improvements involve investigating the land’s previous use before sealing. However, this aspect is not directly covered in the product specification, and would be explored by comparing different layers of data.

mperviousness degree of the centre of Toulouse

Overall, the aim of this product is to monitor the percentage of soil sealing and thus, of impervious areas. Additionally, it will capture the spatial distribution of artificially sealed regions, including the percentage of sealing per unit area, which refers to the extent to which a specific region can be considered impervious.  

How will we improve land management with the “Continuous Imperviousness Monitoring” prototype

At this point the key question arises: How does monitoring impervious areas mitigate environmental impacts in real-world scenarios? Allow us to present some real-life examples. 

  1. Managing floods: Impermeable surfaces prevent water from percolation into the ground, resulting in an increased runoff**. Through the monitoring and regulation of these surfaces, urban planners can alleviate the threat of flash floods caused by intense discharge. This may entail the implementation of more permeable surfaces in the areas, or the development of efficient drainage systems.
  2. Preventing Urban Heat Island Effect: Impervious surfaces retain and emit heat to a greater extent than natural environments, increasing temperatures within urban regions. Monitoring these surfaces allows the adoption of measures such as green roofs, urban vegetation, or reflective materials to mitigate urban heat island effect.
  3. Decreasing habitat and biodiversity loss: Extensive impervious surfaces have the potential to fragment habitats and diminish biodiversity. Monitoring helps in identifying critical areas where the natural environment is under stress, guiding conservation efforts and the integration of green spaces in urban planning.  

Combining Continuous monitoring techniques and novel in situ data to create the prototype

The prototype integrates novel methods developed within EvoLand such as novel in situ data and Continuous monitoring.
 

As for novel-in situ data, our engineers will be using super-resolution Sentinel-2 data at 5 metres to improve spatial resolution of previous High Resolution Imperviousness Copernicus products. Within this process standard image processing techniques are applied, followed by the extraction of various indices to enhance the detection of impervious land surfaces. Additionally, this method foresees the use of hierarchical segmentation, OBIA (Object-Based System Analysis) classification and linear regression. In the matter of continuous monitoring our method will rely on processing data from Sentinel-2, tailored to the specific cycle selected for continuous observation. 

Footnote

*Degradation of stream hydrology: Refers to the negative alteration or impairment of the natural functioning and characteristics of a stream or river system. 

**Runoff: Refers to the movement of the water over land (e.g. movement of the water in a river) 

Would you be interested to follow the results of EvoLand and the development of this candidate prototype? Sign up for our newsletter (here below or via this form), follow us on LinkedIn, Mastodon or X (Twitter). 

Questions about the article or the project? E-mail us at contact@evo-land.eu 

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This article is part of a series providing more details on all 11 EvoLand candidate prototypes 

Previous article in the series: Enhancing sustainability in agricultural practices through cover crop type mapping 

Cover image: Valencia, Spain. Credit: European Union, Copernicus Sentinel-2 imagery

Inline image: Imperviousness degree of the centre of Toulouse. Credit: CLS

 

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