In short a sponge measure is a measure that contributes to improving the sponge function(s) of the landscape and is very site specific, including nature-based solution, a Natural flood measure, etc.
More specifically a sponge measure is a place-specific action that preserves, maintains, restores or enhances ecosystem's abilities to intercept rainfall, slow runoff and temporarily store water, or even create such ecosystems. Sponge measures improve the retention capacity of soils, groundwater and surface water, while providing co-benefits for people and nature through biodiversity and ecosystem services such as enhancing the quality of soils, water and biodiversity. When combined across a landscape, sponge measures reduce flood and drought risks and strengthen climate resilience.
When looking in more details, the concept of “sponge measure” refers to technical solutions that enhance the capacity of an area, often restricted in size, to absorb, store, and gradually release water—much like a sponge. Sponge measures are grounded in three core hydrological principles also named Sponge functions: (1) intercept and infiltrate rainfall, (2) slow down surface runoff, and (3) temporarily store excess water in soils, vegetation, or shallow aquifers. These measures aim to restore the natural hydrological buffering capacity of ecosystems, thereby reducing the impacts of both floods and droughts.Individual sponge measures can act on one and up to three sponge functions. They can be applied individually with mostly local benefits, or combined at landscape scale. These measures provide co-benefits for people and nature through biodiversity and ecosystem services. Sponge measures are generally nature-based solutions (NbS), comparable to natural water retention measures (NWRM), often combining green and hybrid elements. This approach has gained increasing attention in European environmental policy and research, particularly in response to the growing frequency of hydrological extremes driven by climate change. The transition from conventional drainage-based water management to retention-based strategies is now seen as essential for building climate-resilient landscapes.