Soil restoration using compost
0 likes240 views
The Virginia DEQ Stormwater Design Specification No. 4 outlines the use of compost for soil restoration after construction to improve soil porosity and reduce runoff, with noted reductions of up to 50% for certain applications. Key recommendations include soil testing before and after compost incorporation, specific compost specifications, and detailed construction and maintenance sequences. The guidelines aim to enhance urban landscapes while supporting effective environmental management practices.
Soil restoration using compost
- 1. Recommendations from the Virginia DEQ Stormwater Design Specification No. 4 Soil Restoration Using Compost
- 2. Soil restoration is an Environmental Site Design (ESD) practice applied after construction, to deeply till compacted soils and restore their porosity by amending them with compost. These soil amendments can reduce the generation of runoff from compacted urban lawns and may also be used to enhance the runoff reduction performance of downspout disconnections, grass channels, and filter strips. Section 1 - VA DEQ Stormwater Design Specification No. 4
- 3. For simple rooftop disconnection and filter strips, compost amendment decreases annual runoff by 50%
- 4. For grass channels, compost amendment decreases annual runoff by 30%
- 5. Total Phosphorus (TP) and Total Nitrogen (TN) mass load removal is the same: 50% for rooftop disconnection and filter strips 30% for grass channels
- 6. Use compost: Where soils are or will be compacted by grading and construction
- 7. Use compost: Where soils have low infiltration rates
- 8. Use compost: When the area will be used to filter runoff (downspout disconnections and grass channels)
- 9. Use compost: Where mass grading will require more than a foot of cut and fill across the site
- 11. Design criteria: Soil testing pre-construction • Determine soil properties to depth of 1 ft. below the proposed amendment area • Test for bulk density, pH, salts, nutrients • Test every 5000 sq. ft.
- 12. Design criteria: Soil testing 1 week after incorporation • Ensures tilling or subsoiling has achieved design depths • Conduct in conjunction with final construction inspection • Test for nutrients, pH, soil organic matter
- 13. Compost specifications • Manufactured by a member of the U.S. Composting Council Seal of Testing Assurance (STA) program • Pass through ½-inch screen • pH between 6 and 8 • Less than 1% inerts by weight • Organic matter content between 35% and 65% • Soluble salt content less than 6.0 mmhos/cm • Maturity greater than 80% • Stability of 7 or less • C:N ratio less than 25:1 • “Pass” on trace metal test • Dry bulk density from 40 to 50 lbs./cu. ft.
- 14. Construction sequence STEP 1: Prior to building, deep till to a depth of 2-3 feet perpendicular to direction of flow (not required for narrower filter strips) FLOW TILL
- 15. Construction sequence STEP 2: After lot has been graded, 2nd deep tilling to depth of 12-18 inches FLOW TILL
- 16. Construction sequence STEP 3: Wait for dry conditions before incorporating compost
- 17. Construction sequence STEP 4: Incorporate compost at the volumetric rate of 1 part compost to 2 parts soil
- 18. Construction sequence STEP 5: Level, then seed or sod
- 19. Construction sequence STEP 6: If amending more than 2500 sq. ft., use erosion control measures
- 20. Maintenance - general Educate landowners re: routine and long-term maintenance
- 21. Maintenance - general Utilize deed restrictions and other enforceable mechanisms to ensure infiltrating areas are not converted or disturbed Include authority for property inspection and corrective action
- 22. Maintenance - general For more than 10,000 sq. ft. of reforestation, use public right-of-way, deed restriction or conservation/stormwater/drainage easements
- 23. Maintenance – 1st year Months 1-6: inspect at least once after each storm event exceeding ½-inch of rainfall Spot reseed bare or eroding areas to stabilize with grass cover
- 24. Maintenance – 1st year Spot fertilize in the fall after the first growing season, depending on amended soils test
- 25. Maintenance – 1st year Water every 3 days for the first month; weekly during first year (April-October, depending on rainfall)
- 26. Maintenance – ongoing • No requirements for on-going maintenance associated with compost amendments • Optional: de-thatch every few years to increase permeability
- 27. One product | Many benefits | Superior results COMPOST WORKS
- 28. View more titles in the Talking Compost series at www.mcgillcompost.com Production costs for this title were underwritten by McGill. Its use is permitted for educational purposes if presented in its entirety and without editing or other alteration. ©McGill Environmental Systems of N.C. Inc. Questions? Call McGill HQ at 919-362-1161 or use a contact form at www.mcgillcompost.com.