Impermeable surfaces lose attractiveness, softening movements gain momentum

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Urban sidewalks, which help maintain clean and safe streets, generate large amounts of runoff worsen flooding and affect the quality of surface water. In the context of the ecological and climatic crisis, they also contribute to the emergence of heat islands in cities, less water infiltration, less CO2 storage by plants and soiland a loss of biodiversity.

Experts agree that the greening of cities must be stimulated through softening.

The ground surface temperatures of pavement can be significantly warmer than those of grass: 45 degrees Fahrenheit or higher in direct sunlight. Paving is a hard, impermeable surface that is ubiquitous in urban areas. From parking lots and sidewalks to streets and highways, pavement covers vast amounts of land and contributes to a large number Environmental problems.

Cities should be designed like giant sponges that allow water to drain away safely. In the simplest iteration, a spongy city has planned green areas and permeable surfaces that absorb water during times of rainfall. The water seeps into an aquifer for later water use or evaporates and cools the city.

Softening helps an urban space to enhance its spongyness. Softening is the process of removing and replacing unnecessary pavement with plants or trees, permeable paving stones or permeable asphalt. Softening allows rainwater to soak into the ground where it falls, instead of picking up pollutants and transporting them to creeks and waterways. There is a large network of water softening groups worldwide: Portland, OR, Chicago, Tennessee, Ontariothe United Kingdomand more.

What are some approaches to mainstream softening practices into urban renewal processes and planning instruments? Which type do you choose?

Water permeable: With water-permeable soil materials, the water passes through the material because it is porous; the water runs along the material through the joints, perforations in the material or between the material. Examples of this are grass tiles, shells, grass pebbles, gravel or bare soil. Softening and/or the use of loose, permeable ground covers should be done whenever possible, but in a manner that allows autocirculation and minimizes dust generation, especially during gusty winds and dry storm conditions.

Introduction of vegetation: Trees, shrubs and ground covers can be planted in the unpaved strips along the sidewalks. Trees and taller shrubs should be planted in a scattered manner to avoid capturing long-wave radiation, exhaustion fumes and blocking the wind (more effective if the prevailing wind direction is parallel to the street), thus authors in the news Sustainable development. Ground covers can be combined with trees and shrubs to reduce their vulnerability to damage from stairs or improper parking. These green bags are interspersed with parking spaces so as not to endanger mobility and functionality, such as deliveries to shops. Climbing plants can be placed in facades, planted directly on the ground or in raised planters.

Customize urban materials: The dimensions of the facade and ground area are increased by applying light-colored paint or by recoating them with cool surface materials. It can be a reflective coating spread over asphalt: a mixture of asphalt, water, mineral fillers, polymers and recycled material. No harmful chemicals from the surface should be released into green spaces or waterways. This is not an adequate solution for areas with heavy car trafficbut if it's a surface where people walk their dogs, walk their kids, or play basketball, then it could be a good start.

Depaving Case Study #1: Somerville, Massachusetts

Green & Open has been organizing softening parties in Somerville, Massachusetts for ten years. Tearing asphalt from a garden provides access to a healthy green space. The newly exposed soil, planted with native plants, can absorb rainwater that would otherwise jump over previously impermeable surfaces. In heavily paved cities like Somerville, softening captures excess rainwater, additions of plants and greenery lower surface temperatures and remove carbon dioxide from the atmosphere. Green & Grass has:

• fought against the installation of artificial grass on grass sports fields;
• lobbied for significantly stronger sustainability language in urban zoning;
• advocated for a minimum ordinance for native plants – the first in the country;
• raised awareness of the need to halt the deteriorating canopy; And ,
• organized community events to plant gardens of native species, weed invasive plants and create plant gardens in heavily paved areas.

If described by a Boston sphere In this article, a volunteer clamps a long metal rod under the asphalt, where it ends up in a green space. The first volunteer pushes the bar down with his weight, while a second volunteer swings a sledgehammer over his shoulder and head and then slams it into the ground. After a few big swings, the asphalt cracks.

The goal of their interest group is to identify the most critical areas within the urban context need to be hardened for green canopies, trees, green roofs and other water-permeable solutions.

Case study #2: Flanders, Belgium

Flanders is one of the most paved areas in Europe 16% of the surface is paved. Projections expect that more than 20% will be paved by 2050 unless there is a significant change in urban construction.

Rather than settle for the inevitable, the city is physically removing paved space, such as roads, parking lots, buildings, patios and driveways, to restore soil permeability and enable various other natural ecosystem functions. These actions invite more space for nature and food production, less flooding, a cooler city, greater biodiversity, better soil quality, healthier air and a more pleasant living environment.

Advocacy works by facilitating, supporting and supervising softening projects, but also by generating and disseminating knowledge and learning lessons regarding the softening that takes place in Flanders.

In a projectwater is used as efficiently as possible: the collectible rainwater is disconnected from the sewer system and buffered on site. Rainwater is reused and wadis and additional infiltration zones are created.

Attention is also paid to biodiversity by offering native, regional plants, taking the flowering month into account.

The Flanders project recognizes that safety, accessibility or the type of surface sometimes require a certain degree of hard surface. In such a case, water-permeable/water-permeable paving offers an alternative. These ensure that more rainwater can infiltrate, replenishing groundwater, reducing pressure on the sewerage system and limiting drought stress.