Irving's Grow Zone Program
The City of Irving has created a Grow Zone Program where it provides focus to city owned properties in an effort to positively impact the environment. A “Grow Zone” is an area where mowing is restricted and vegetation is allowed to grow.
Grow Zones help to improve the quality of our soil, water, and air, and also help to provide habitat structure for native and migrating wildlife. Ideally, Grow Zones should contain native and diverse vegetation, which helps to maximize ecosystem services provided by these spaces, and improve overall biodiversity.
Currently, Irving targets city-owned drainage swales and areas along streams as viable places for these Grow Zones.
Visit our Stormwater Interactive Mapping page to view current Grow Zones in the City of Irving.
Types of Grow Zones
Bioswales : are vegetated zones that rest within low-lying areas and that have water channeled through them.
Bioswales are a type of green infrastructure, or blue green infrastructure - as the concept has developed - and are designed to manage water quality and quantity in a watershed. Blue green infrastructure adopts a nature based solution to better help build more resilient communities, expand ecosystem services, and promote biodiversity.
The city chose existing drainage swales as viable locations for creating these bioswales. Historically, these swales were mowed and had aggressive turf grasses growing in them. In some areas, such as Running Bear Park, the undesirable grasses and other vegetation are removed from the site, and the area is seeded for native vegetation: wildflowers, prairie bunch grasses and other native plants. The soil is also prepped in these areas, where soil is transplanted from local riparian and prairie habitats in an effort to inoculate the new area with beneficial microbes, and transplant existing native seed banks from those habitats. The idea takes an ecosystem restoration approach, where we try to restore the ecosystem back to how it previously was before settlement and development occurred. This approach reduces maintenance requirements, and improves the environment in numerous ways.
Sensitive Streamside Areas : are a type of Aquatic habitat found alongside streams that have been left natural with existing and or native seeded vegetation, and that have restricted maintenance activity.
Sensitive Streamside Areas are one example of an environmentally sensitive area, and can also be understood and described as a protected riparian habitat or buffer. Often these areas have been developed over and right up to; when this happens, erosional evens are more likely to occur, as well as flood events and water pollution...not to mention habitat destruction that impacts wildlife. When riparian buffers are maintained, they can often have turf grass present, and that is put on a regular mowing schedule. Not only is this approach labor intensive and harmful for air quality, but it offers little biodiversity and limits potential ecosystem services provided.
More Info & Benefits of this habitat
From an ecosystem perspective, areas that exist along the edges of any aquatic habitat are referred to as riparian habitat. Riparian buffers are important habitat corridors for wildlife and act as a natural buffer from pollution. It’s helpful to think of these areas as sponges that help to soak up and sequester any potential pollutants that pass through them. Microbial life in the soil helps to cycle nutrients and breakdown many of these pollutants, allowing for uptake by plants, and cycling back into the atmosphere.
Maintaining Riparian buffers are helpful for many reasons, including preventing erosion, as the roots of the plants - especially native grasses - help to bind and stabilize the soil in place. This same action of the plants roots also helps to encourage infiltration of stormwater into the ground. As is the case with bioswales - or any habitat with diverse and robust vegetation that is left to grow natural, air quality is improved through reduction of CO2 and air pollutants from the atmosphere, and cooling of ambient and surface temperatures.
The city looks for areas alongside stream corridors that have existing turf grasses present, and or erosion concerns. These areas already have preserved buffers from developments, and so are prime for instituting as a Sensitive Streamside Area.