How do I build a rain garden in Portland Oregon?
Dig a hole two feet deep and two feet wide where the deepest part of the rain garden will be. Fill the hole with water and let it drain completely. Fill it again and monitor how fast the water drains. If it drains within 24 hours, this is a good spot to locate a rain garden.
What are the zones of a rain garden?
There are three rain-garden zones, each for a different microclimate within a rain garden: Bottom – typically bottom of a basin or swale. Prone to temporary pooling of water and cold air (cool night air pools in low spots). Terrace – typically atop a terrace or pedestal within—or on bank of—a basin or swale.
How deep is a rain garden?
between four and eight inches deep
A typical rain garden is between four and eight inches deep. A rain garden more than eight inches deep might pond water too long, look like a hole in the ground, and present a tripping hazard for somebody stepping into it.
How do you build a rain garden?
Create the rain garden by building a berm in a low spot in the yard, then build swales to channel runoff from the gutters and higher parts of the yard. The water is then absorbed into the soil through the network of deep plant roots. Use a mix of plants adapted to your area and to the different water depths.
Where does a rain garden water go?
Rain gardens collect rainwater runoff, allowing the water to be filtered by vegetation and percolate into the soil recharging groundwater aquifers.
When should I plant a rain garden?
Although a rain garden can be installed anytime the ground is not frozen, spring and fall are the best times to start your garden. In spring, the soil is easier to dig and the rainy weather means less initial watering.
Can you plant trees in rain gardens?
Rain gardens are attractive landscaping features that can not only improve the aesthetics of most properties, but they provide important environmental benefits too. Most of the vegetation planted in rain gardens consists of shrubs and herbaceous plants, but you can also install trees in a rain garden if you wish.
How long does a rain garden last?
It typically holds water only during and following a rainfall event. Because rain gardens will drain within 12-48 hours, they prevent the breeding of mosquitoes.
How effective are rain gardens?
Rain gardens are effective in removing up to 90% of nutrients and chemicals and up to 80% of sediments from the rainwater runoff. Compared to a conventional lawn, rain gardens allow for 30% more water to soak into the ground. Because rain gardens will drain within 12-48 hours, they prevent the breeding of mosquitoes.
How is green infrastructure used in Portland Oregon?
The resulting stormwater runoff carries dirt, oil and other pollutants to rivers and streams and can also cause erosion and flooding that harm properties and wildlife habitat. Portland uses green streets, ecoroofs, trees, and other green infrastructure to manage stormwater, protect water quality and improve watershed health.
What is the stormwater management manual for Portland Oregon?
The manual provides policy and design requirements that govern stormwater management. All development, redevelopment, and improvement projects within Portland on private and public property and in the public right-of-way must meet SWMM requirements.
How old is the sewer system in Portland Oregon?
Urban streams, forests, and wetlands manage stormwater naturally and are part of Portland’s green infrastructure. Over one-third of Portland’s 2,500 miles of sewer pipes are more than 80 years old.
When does the 2020 SWMM become effective in Portland?
MSTT vendors can submit their product for review using the 2020 SWMM MSTT Application Form. The City of Portland 2020 SWMM became effective Dec. 14, 2020. From the effective date until Apr. 6, 2021, project designers could choose to use either the 2016 SWMM or the 2020 SWMM.