Backyard Wetland: Building a Wetland in an Existing Wet Area or Drainageway
Backyard Wetland
Building a Wetland in an Existing Wet Area or Drainageway
In some instances, all you need to do is stop mowing during dry periods. Too often homeowners go to great lengths to establish plants that are not adapted to the site or to modify the site, when it would be more effective to use plants suited to the conditions. Numerous landscape plants are well adapted to wet conditions and will provide beauty as well as wildlife habitat. Be sure to check the growth and rooting characteristics of trees you want to plant. Many wet soil tolerant trees have shallow root systems or brittle branches and must be planted a safe distance from buildings.
Partially blocking a drainageway or small ditch to create your wetland by trapping storm water needs more planning. Where a low berm less than a foot high will create a small wetland, planning is not complicated if:
• The drainage area above the berm is small, generally less than an acre;
• There is adequate area for flood flows to go around and over the berm; and
• The soil contains a high percentage of clay.
For sites requiring a higher berm, and those with a larger watershed, you need engineering advice. For sites with sandy soil or a lot of rocks, you also may need to install a plastic liner (described in the next section) under all or the lower portion of your wetland.
To construct the wetland with a small berm to hold back water for a few days or weeks:
1. Put a stake in the center of the lowest portion of the drainageway where you want the berm.
2. Using a level on a large board or string, place a stake where a level line reaches the ground on either side.
3. Using the same type of level, mark how far back water will be impounded at the top of the berm.
4. Remove any existing sod from an area about 4 feet wide along the line of the berm and over about half the area that will be flooded.
5. Dig a trench about 1 foot deep along the center line of the berm and fill it with slightly damp heavy soil, packed down firmly.
6. Build your berm about 4 feet wide at the bottom and 1 foot at the top. The center should be 4 to 6 inches higher than the ends to allow for settling and to force water flowing over it around the ends, reducing the likelihood of erosion.
7. Cover the compacted berm with purchased grass sod or the sod you originally removed from the area.
8. Plant wetland adapted plants in bands from the deepest areas to an area about six inches above the expected high water level, selected according to the degree of soil saturation they require.
Building a Wetland in an Existing Wet Area or Drainageway
In some instances, all you need to do is stop mowing during dry periods. Too often homeowners go to great lengths to establish plants that are not adapted to the site or to modify the site, when it would be more effective to use plants suited to the conditions. Numerous landscape plants are well adapted to wet conditions and will provide beauty as well as wildlife habitat. Be sure to check the growth and rooting characteristics of trees you want to plant. Many wet soil tolerant trees have shallow root systems or brittle branches and must be planted a safe distance from buildings.
Partially blocking a drainageway or small ditch to create your wetland by trapping storm water needs more planning. Where a low berm less than a foot high will create a small wetland, planning is not complicated if:
• The drainage area above the berm is small, generally less than an acre;
• There is adequate area for flood flows to go around and over the berm; and
• The soil contains a high percentage of clay.
For sites requiring a higher berm, and those with a larger watershed, you need engineering advice. For sites with sandy soil or a lot of rocks, you also may need to install a plastic liner (described in the next section) under all or the lower portion of your wetland.
To construct the wetland with a small berm to hold back water for a few days or weeks:
1. Put a stake in the center of the lowest portion of the drainageway where you want the berm.
2. Using a level on a large board or string, place a stake where a level line reaches the ground on either side.
3. Using the same type of level, mark how far back water will be impounded at the top of the berm.
4. Remove any existing sod from an area about 4 feet wide along the line of the berm and over about half the area that will be flooded.
5. Dig a trench about 1 foot deep along the center line of the berm and fill it with slightly damp heavy soil, packed down firmly.
6. Build your berm about 4 feet wide at the bottom and 1 foot at the top. The center should be 4 to 6 inches higher than the ends to allow for settling and to force water flowing over it around the ends, reducing the likelihood of erosion.
7. Cover the compacted berm with purchased grass sod or the sod you originally removed from the area.
8. Plant wetland adapted plants in bands from the deepest areas to an area about six inches above the expected high water level, selected according to the degree of soil saturation they require.
Backyard Pond - Backyard Wetland - Composting - Mulching - Terracing Slopes