How are rain gardens calculated?

How are rain gardens calculated?

The two tables are different because some water will infiltrate as it flows over the lawn for 30 feet or more. Determine Rain Garden Size for 100% Runoff Control 1. Multiply total drainage area by the soil factor. This gives you the size to build the rain garden in square feet.

How much rain can a rain garden handle?

Therefore, rain gardens should be designed to handle the runoff from 1.25 inches of rain. This size of an event is called the water quality volume (WQv).

How deep can a rain garden be?

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 drainage?

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 should I put my rain garden?

Choose the Site. Your rain garden should be located at least 10 feet from the house. A natural site is a low spot in your yard that often collects water after a heavy rain. Ideally this area receives full sun, but at a minimum it should receive a half day of sunlight.

How long should a rain garden hold water?

Rain gardens are built to hold water during rain events, however water should infiltrate the ground within 24 hours.

What do you call an area that receives less than 10 inches of rain per year?

Deserts are arid ecosystems that receive fewer than 25 centimeters (10 inches) of precipitation a year. Deserts are areas that receive very little precipitation.

What are different components of the soil mixture in the rain garden?

Fill the rain garden with soil media mix: The soil mix placed back in the excavated rain garden, or hole at this point, should consist of ~ 50% sand, 25% topsoil, and 25% compost. Additional sand can always be added to the mix but limiting your clay content in the mix is very important.

How to calculate drainage area for rain garden?

Calculate Drainage Area 1. Go out to the area designated for the rain garden. Identify the section of roof that will drain into the downspout. Measure the length and width of this area. Take measurements of other hard surfaces such as driveways, parking areas, or sidewalks that may drain into the rain garden.

What are the steps in designing a rain garden?

The document takes you through the six simple steps involved in designing a rain garden: 1/ Choose the right location 2/ Composition of a rain garden 3/ Calculate the size and depth 4/ Consider infiltration 5/ Manage flows 6/ Select the planting Q u a l i t y A m e n i t y Q u a n i t y Maintain and protect the natural water cycleQ u a n t i t y

How big does a rain garden need to be?

During construction, the rain garden is excavated and then backfilled with planting media or existing soil that has been amended with compost. Leave a depth of six-inch from the top of the soil for temporary ponding. The total excavation depth typically ranges from one to three feet, depending on the design.

How to determine soil factor for rain garden?

Determine the Soil Factor 1. The soil factor is a number derived from soil type and rain garden depth. Locate the correct soil factor on the tables to use as the multiplier with drainage area. 2. The worksheet has two sets of factors. Use the table #1 for rain gardens closer than 30 feet from the downspout.