Sponge City ecological porous fiber cotton and carbon fiber rainwater collection modules are composed of capillaries with diameters of 3-5 micrometers, equivalent to numerous tiny microtubes interwoven together. As a result, the product exhibits capillary force, meaning that when it comes into contact with liquid, capillary action occurs. Examples include towel absorption and groundwater rising through soil, both of which are capillary phenomena. Working Principle and Performance: Since the density and capillary force of dry soil are greater than those of the fiber cotton, when both come into contact with water simultaneously, they begin absorbing water at almost the same rate, eventually reaching a dynamic equilibrium with consistent moisture content to achieve water balance. Through such microscopic natural processes, functions like water absorption, water retention, and drainage are achieved. Vegetation Protection Currently, China lacks specific regulations for green roofs, with local standards generally consistent, requiring a load-bearing capacity of at least 100 kg/m2 for simple roofs. Therefore, when both come into contact with water simultaneously, they begin absorbing water at almost the same rate, ultimately reaching a dynamic equilibrium with consistent moisture content.

When soil contacts water first and the product later comes into contact with saturated soil, excess water in the soil gradually releases into the porous fiber cotton, achieving a dynamic balance of moisture content. When both lose water under natural conditions, due to the soil's capillary force being greater than that of the fiber cotton module, the soil continuously absorbs water from the fiber cotton module. Meanwhile, plant roots can fully penetrate the product without altering its performance.

Ecological porous fiber cotton and carbon fiber rainwater collection modules do not expand or deform after absorbing water, with a load-bearing capacity of 5-25 kg per square meter, preventing collapse. Since the product is made of rock-like materials and its properties are similar to soil, its water release rate closely mimics natural soil, slowly releasing into the ground as needed. This characteristic prevents rainwater from accumulating underground in the areas where the product is used. The load-bearing capacity of the pavement it can withstand is closely related to its burial depth and the upper fill materials such as soil, gravel, and pebbles. Traditional synthetic buffers are prone to surface damage and overall collapse, requiring frequent replacement. The ecological porous fiber module can resist erosion from plants and tree roots, primarily because the material itself and its outer membrane provide some resistance to root penetration. Small roots may adhere to the surface of the ecological module, while larger plant roots may penetrate it, resulting in a loss of water storage capacity in the penetrated areas. Each individual unit can perform its own buffering, drainage, and infiltration functions. Depending on the extent of surface water accumulation, the amount of rainwater to be managed on-site, and soil texture, installation options include dispersing single units or connecting two or more units in series.