For community greenspaces, schools, business parks, churches, and other facilities with large drainage areas.
In this case, the rain garden is in a community greenspace, 30 feet in front of a concrete culvert, which drains the parking lot above.
The sod can be used elsewhere on your property.
Since there is so much excess soil to remove, most of the soil will have to be hauled off to a disposal facility. A small fraction of the excess soil will be used to create the berm.
Soil should be bermed on the lower side of the rain garden to stop water from exiting the garden and allowing the water to soak into the soil.
The amount of amendments will depend on the size of your garden. When finished adding sand, compost, and/or manure, there should be a distance of approximately 5-6 inches from the surface of the surrounding land. This space allows for 2-3 inches of mulch and extra water holding capacity.
Before digging and planting, place the plants in the location you want them to be.
Cover with a 2-3 inch layer of shredded hardwood mulch.