Comprehensive Environmental Inc (CEI) - LID Committee - Salem, NH Raingarden Demonstration Project

For more information on these raingardens follow the links below.

This photo was taken on August 5, 2005.

Comprehensive Environmental Inc (CEI) provided funds for this Low Impact Design (LID) raingarden Project located in the Merrimack River watershed, in the Town of Salem, New Hampshire. CEI's LID Committee personnel served as the technical consultants for this project to identify a location for the project, design the raingarden, as well as providing the labor for the actual construction.

The project location had to fit several criteria:

an area that could capture and infiltrate stormwater runoff discharging to nearby stormdrains and eventually to the Merrimack River watershed.
an area that would provide an educational benefit

The area in the backside of the cul de sac (where the ponding occurs) was chosen for the raingarden.

Construction of Rain Garden

On May 11, 2005 the garden area (1000 square feet) was excavated and landscaped. Because of multiple storms the plantings were not placed and the garden completed until August 11, 2005.

An existing catch basin in the garden area was covered with filter fabric during construction to prevent sediment from washing into the drainage system. A 4 foot hole was excavated in the center of the garden. The raingardens are dug so that they are tied into soils that lie below the normal frostline. Stone or slotted PVC tubing is then used to promote drainage in the bottom of the raingarden. This keeps the drainage working during winter months, preventing total freezing. The holed area was then covered with filter fabric and filled with rocks provided from the excavated area.

The rock area was covered with the filter fabric and a 4" mixture of 50% native soil and 50% compost was spread over the garden area landscaped so that a depressed area was formed.

The compost-amended soil has many potential benefits when instituted with establishment of turf and landscaping, including:

increased water conservation,
increased nutrient retention,
better turf aesthetics,
reduced need for chemical use,
improved stormwater retention, and
cost-savings to the private landowner.

The area was planted with live plants on August 11, 2005 and a two inch Hemlock mulch covering, was placed to prevent erosion from the exposed soils and to protect the plants.

Native plants were selected for their ability to grow in various depths of water and soil moisture conditions.

The delay in planting was caused by multiple storms.

Problems
The garden kept having plants run over by delivery trucks cutting the corner too close. Markers were added to draw attention to the boundaries of the garden.

Pre Construction Photos

Pre-construction	Pre-construction

During-construction Photos (05-11-05)

Construction of catch basin	Catch basin covered with filter paper	landscaped area

During-construction landscaping Photos

Constructed garden	Final garden August 5, 2005

Click any thumbnail for a larger view. Photos above taken by CEI LID Committee members.