Page 31 - Section4.2.1-SWPPPCutSheet-FiltrexxStormWaterBlanket

394 | Filtrexx ® Low Impact Design Manual | Version 8.0

discharge point will serve this purpose.

• Overfow Outlet – All Rain garden facilities must provide a means for excess water to overfow and be conveyed downstream.

INSTALLATION

1. Filtrexx ® GrowingMedia tm used for Rain garden facilities shall meet all Filtrexx ® specifcations.

2. Contractor is required to be Filtrexx ® Certifed tm Installer determined by Filtrexx ® International, LLC (440-926-8041; Filtrexx.com). Certifcation shall be considered current if appropriate ID is shown at time of bid or time of application (list found at www.fltrexx.com). Look for Filtrexx ® Certifed tm Installer Seal.

3. Schedule a pre-construction meeting with Engineer, Filtrexx ® Certifed tm Installer , and any other consultants that will be involved in the Rain garden installation.

4. Rain garden facilities will be placed at locations indicated on plans as directed by the Engineer.

5. Rain garden areas should be protected from compaction during the site construction phase.

6. Construction site shall be graded and stabilized prior to the installation of Rain garden facilities.

7. In-situ soils compacted during site construction shall be roto-tilled to 18 in (450mm) to restore porosity and infltration cap. in areas designated Rain garden.

8. Excavation/grading of Rain garden area shall be done w/ equipment outside limits of Rain garden system, or equipment w/ marsh tracks or light equipment w/ turf tires.

9. Rain garden areasmust be protected fromerosion and sedimentation after fnal grades have been established for the facility.

10. Install underdrain systemandobservationwells, if specifed.

11. Rain garden soil mix shall consist of 25% Filtrexx ® GrowingMedia tm and 75% coarse (grain size 0.02 in – 0.04 in [0.5-1.0mm]) construction sand that is clean and free of deleterious materials. The soil shall be mixed thoroughly to ensure a homogonous and consistent texture.

12. Rain garden soils shall be installed in lifts of 12 – 18 in (300-450mm). Each lift shall be lightly watered to encourage natural compaction. No mechanical compacting .

13. Rain garden base should be at least 2 ft (600mm) above bedrock or geologic structures.

14. Rain garden soil mix shall have a minimum infltration rate of 2 in (50mm) per hour.

15. Ensure that fnal grades are achieved as specifed, taking into account the mulch layer that will be added after planting. Fine grading is extremely important for Rain gardens facilities. They are typically only 6 in (150mm) deep so an error of 2 in (50mm) may cause a 33% change in storage volume!

16. Install vegetation specifed in the planting plan.

17. Install a 3 in (75mm) Filtrexx ® FilterMedia tm blanket as mulch over the entire Rain garden area, or as specifed by the Engineer. Install erosion control at entrance points in the form of surge stone or river rock, or as specifed.

18. New planting may require irrigation during establishment.

INSPECTION and MAINTENANCE

Regular inspection should occur throughout the installation process at the following times:

1. Pre-construction meeting.

2. Stabilization of construction site and beginning of excavation.

3. Installation of underdrain.

4. Delivery and installation of soil materials, including GrowingMedia tm .

5. Establishment of fnal grades of Rain garden facility.

6. Delivery and installation of plant material.

7. Delivery and installation of FilterMedia tm blanket or mulch.

8. Establishment phase of plant material. Regular maintenance shall include:

9. The Contractor shall ensure that the site upstream from the Rain garden area remains stabilized and does not contribute excessive sediment that may impair the performance of the Rain garden area.

10. Plant materials may need to be irrigated during establishment.

11. Plant materials that do not establish, may need to be replaced.

12. The Rain garden facility should be monitored for invasive non-native plant species. Any that are found should be eradicated.

13. FilterMedia tm should be replaced as necessary to ensure complete coverage of the surface of the Rain garden area.