Stormwater Wetlands: Match Species to Water Levels

 

The single most important factor governing plant survival in stormwater wetlands is matching the species to the water level.

 

In the past, many wetlands failed because the plants were installed in water that was too deep.  As a result, many stormwater wetland design guidelines have recently changed and can be quite confusing.

 

Here is how plants in stormwater wetlands naturally divide themselves.  These natural planting zones are all relative to the wetland's normal water level, which is typically determined by a small drawdown orifice or a small dam-like weir.

  • One group of plants grows from just above the water's edge up 6 to 12 vertical inches.   We call these 'shallow land' plants.    
  • Another group grows at the water's edge - an inch above to an inch below.  We call these 'water's edge' plants.
  •  The third group grows from the water's edge down into 6" of water.  We call these 'shallow water' plants. 
  • A small group of plants grow in water more than 6" deep.  We call these 'deep pool' plants.  

 

 

 Chowan County Golf Course

Different states may break up planting zones a bit differently than the plants do.  So know where the water level of your wetland is designed to be, then mark your planting areas up or down from that level.