Page 9 - Section4.2.1-SWPPPCutSheet-FiltrexxStormWaterBlanket

370 | Filtrexx ® Low Impact Design Manual | Version 8.0

around areas contributing overland and subsurface storm water fows.

5. Engineered soil shall not be installed in areas of concentrated runoff fow without soil stabilization or armoring devices.

6. Engineered soil shall not be installed on slopes greater than 3:1, and on slopes greater than 4:1 shall include slope stabilization practices.

7. Engineered soil should not be installed in wet or frozen soils or prior to seasons where growing vegetation is diffcult.

8. Care should be given to existing root systems of trees and shrubs during construction of Engineered soil.

9. Seed shall be thoroughly mixed with the GrowingMedia tm prior to construction of Engineered soil or surface applied with Growing Media tm at time of application.

10. Land surface shall be cleared of debris, including rocks, roots, large clods, and sticks prior to Engineered soil installation or tillage.

11. Soil may be prepared prior to GrowingMedia tm application by roto-tilling the native soil; or soil ripping may be used as a prerequisite if soil is too dense.

12. Subsoil may be scarifed to a depth of 4 in. (100mm) prior to GrowingMedia tm application.

13. GrowingMedia tm shall be evenly applied to the soil surface at a depth of 2-4 in (50-100mm) or 270-540 cubic yd/ac (513-1026 cubic m/ha) using a pneumatic blower, spreader, or similar device (small installationsmay be donemanually) and thoroughly roto-tilled into the native soil (several passes my be required); or

14. GrowingMedia tm shall be mixed with native soil prior to construction using a loader, soil mixer, or similar equipment

15. Soil incorporation and tillage shall be to a min. of 6 in (150mm) (unless restricted by tree roots or other natural constraints) and a max. of 12 in (300mm); or

16. If subsoil is scarifed to 4 in (100mm)., soil incorporation should be 6-8 in (150-200mm).

17. Engineered soil shall be thoroughly watered after installation and allowed to settle for 1 week; fne grading and hand rolling of Engineered soil may be required after installation.

INSPECTION and MAINTENANCE

Routine inspection should be conducted within 24 hrs of a runoff event for 1st year after installation/ until permanent vegetation has established. If rilling occurs/vegetation does not establish, the area of

application should be reapplied with Engineered soil. Runoff diversion devices, Slope protection, RECBs, or soil stabilizers should be considered until vegetation has established. Vegetation should be inspected for noxious/invasive weeds. Periodic infltration rate tests may be performed to ensure system is performing correctly.

1. The Contractor shall maintain the Compost Engineered Soil tm in a functional condition at all times and it shall be routinely inspected.

2. Heavy equipment should be limited on and near the engineered soil to prevent compaction that will reduce infltration and permeability.

3. If Engineered soil becomes compacted, or infltration and permeability rates diminish signifcantly, Engineered soil shall be reinstalled or replaced with a functioning alternative.

4. Engineered soil shall be maintained until a minimum uniform cover of 70% has been vegetated, permanent vegetation has established, or as required by the jurisdictional agency.

5. Engineered soil may need to be irrigated in hot and dry weather and seasons, or arid and semi- arid climates to ensure vegetation establishment.

6. Where Engineered soil fails, rilling occurs, or vegetation does not establish the Contractor will repair or provide an approved and functioning alternative.

7. If Engineered soil is damaged by storm water runoff prior to vegetation establishment, temporary runoff diversion devices installed above the Engineered soil may be required.

8. No additional fertilizer or lime is required for vegetation establishment and maintenance.

9. Regular mowing of grass vegetation on Engineered soil to a minimum height of 4 in (100mm) and a maximum height of 10 in (250mm) will deter invasive weeds, allow sunlight to kill captured pathogens, and provide maximum sediment removal effciency and sediment storage capacity in the vegetation.

10. Organic debris and clippings should be left on- site to maintain soil organic content.

11. Sediment shall be removed if it reaches 25% of the height of the vegetation (mowed) to prevent diversion of runoff and reduction of vegetation health and cover.