User:Yujunliu/sandbox

Green infrastructure appears at all scales, including regional, corridors for wildlife, city planning, and smart communities.

Urban forests

Urban forests are forests located in cities. They are an important component of urban green infrastructure systems. Urban forests use appropriate tree and vegetation species, instead of noxious and invasive kinds, which reduce the need of maintenance and irrigation. In addition, native species also provide aesthetic value while reducing cost. Diversity of plant species should also be considered in design of urban forests to avoid mono-cultures; this makes the urban forests more durable and resilient to pests and other harms.
In the United States, a federal legislation known as The Energy Conservation Through Trees Act, authored by Congresswoman Doris Matsui of Sacramento, encourages residents to plant shade trees to reduce heating and cooling costs.

Benefits of urban forests:

• Energy Use: According to a study conducted by the Lawrence Berkeley National Laboratory and Sacramento Municipal Utility District, it was found that urban trees can provide up 47% energy savings.
• Urban Heat Island: Maximum air temperature for tree groves were found to be lower than that of open areas without trees. This is because of a process called evaporative cooling.
• Water Management: Urban forests helps with city water management on diverting storm water from water channels. Trees intercept a large amount of rainfall that hit them.
• Air Pollution: Trees hold carbon, which improve air quality in cities.
• Property Values: Having more trees increases property value, which suggests that people value greenery and trees wherever they are. This implicates that trees contribute to the preferred living conditions. Urban greenery can also improve mental health and well-being.

Constructed wetland

Constructed wetlands are manmade wetlands which work as a biofiltration system. They contain wetland vegetation and are mostly built on uplands and floodplains. Constructed wetlands are built this way to avoid connection or damage to natural wetlands and other aquatic resources. There are two main categories of constructed wetlands: subsurface flow system and free water surface system. Proper planning and operating can help avoid possible harm done to the wetlands, which are caused by alteration of natural hydrology and introduction of invasive species.

Benefits of constructed wetland

• Water efficiency: Constructed wetlands try to replicate natural wetlands’ ecosystems. They are built to improve water efficiency and water quality. They also create wildlife habitats by using natural processes of plants, soils, and associated microorganisms. In these types of wetlands, vegetation can trap parts of suspended solids and slow down water flow; some other pollutants are processed by the microorganisms that live there.
• Cost-effective: Wetlands have low operating and maintenance costs. They can also help with fluctuating water levels. Aesthetically, constructed wetland are able to add greenery to its surrounding environment. It also helps to reduce unpleasing odors of wastewater.

Green roof and green walls

Green roofs improve air and water quality while reducing energy cost. The plants and soil provide more green space and insulation on roofs. Green roofs also help reducing city runoff by retaining rainfall.

GIS applications

A geographic information system (GIS) is a computer system for that allows users to capture, store, display, and analyze all kinds of spatial data on Earth. GIS can gather multiple layers of information on one single map. The information includes streets, buildings, soil types, vegetations, and more Planners can combine or calculate useful information such as impervious area percentage or vegetation coverage status of a specific region to design or analyze the use of green infrastructure.

Green Infrastructure Master Plan

According to the Green Infrastructure Master Plan, developed by Hawkins Partners, civil engineers use GIS to analyze the modeling of impervious surfaces with historical Nashville rainfall data within the CSS (cmbined sewer system) to find the current rates of runoff.
GIS are able to help planning teams analyze potential volume reductions at the specific region for green infrastructures, including water harvesting, green roofs, urban trees, and structural control measures.