Rain Garden Design Templates

The analysis phase of the design process assigns values to the information you gathered during the inventory phase. Review inventory information and assign relative importance values to the information which is subjective (importance of blocking a bad view) and calculate the necessary information required to quantify site information and determine the materials quantities needed. For example, in the inventory, areas of water standing and sources of water were identified and quanitified by SF. In the analysis, this information is used to determine the optimal location and size (SF and volume) of the rain garden.

A. Determine optimal placement and size for rain garden based on:
	1. Moisture/water issues
		Where is the water standing after a rain What is the water source What is the direction of water movement on the property Determine where water would enter a rain garden and where it would exit the garden Identify places closest to the water source to catch the water before it reaches the lowest point Determine where the low point of the garden should be Decide if it would be appropriate to create more than one rain garden and if more than one, if they will be linked (if to be linked decide if it will be overland or via a pipe)
			NOTE: The placement of the rain garden may be in a natural depression which already collects water or may be sited uphill from that depression to intercept the water so that it is addressed infiltrated prior to reaching the current depression. In all cases, the rain garden will benefit from having a grassy strip in the area uphill from the garden to act as a sediment filter for the entering water. The diversion of water into the garden may be done through a reshaping of the earth adjacent to the garden, by lowering the finished ground elevation of the surface of the garden or by piping water directly to the garden.
	2. How people move through the area/ who will see it 3. Other design considerations such as views, wildlife, desired proximity 4. Cost of excavation based on the rain garden placement

B. Determine which template to use based on:
	1. Planting Hardiness Zone and physiographic region 2. Light levels (sun or shade) 3. Moisture – will this be an underdrained or self-contained rain garden 4. Soil types – existing soil and how much removal / amendment is going to be done 5. Desired social, environmental and aesthetic functions of the garden 6. Desired maintenance practices
			NOTE: This information can also be used to determine which plant list to select if the design template will be modified in size; local availability may also require plant substitutions and information from this step will provide guidance regarding appropriate list selection and plant substitutions to make to achieve the desired water quality and other benefits.