Soil erosion -- the impact of rain/irrigation water running across unprotected soil -- doesn't just scar the landscape. That runoff carries sediment and pollutants to surface waters. Mitigating the impacts of erosion cost money. But compost use has been proven to be an effective money-saver compared to more traditional erosion control methods.

1. Cutting the Cost
of Soil Erosion

2. Soil erosion has been identified as one of the
biggest environmental problems facing the
world, second only to population growth.

3. Since natural soil regeneration takes longer
than a human lifespan, soil is not
considered a renewable resource.
Average human lifespan = 79 years
Average time to for nature to generate 1 cm of topsoil = 100 years
10 20 30 40 50 60 70 80 90 100
SOURCE: UK House of Commons Environmental Audit Committee

4. Global erosion costs
about $400 billion each year
SOURCE: US National Institutes of Health

5. Soil loss from construction is 10-20
times that of farm land.
SOURCE: Journal of Soil and Water Conservation

6. 60% of lost soils pollute aquatic
systems with nutrients, pesticides
and other contaminants
SOURCE: Soil management techniques to improve green stormwater infrastructure

7. 850 billion gallons of untreated
water are discharged into U.S.
waters annually
SOURCE: Environmental Health Perspectives

8. As much as 90% of city surfaces
are impervious, resulting in
5 billion tons of topsoil lost each
year to erosion
SOURCE: NCSU Water Resources Research Institute

9. Runoff from unstablized
construction sites can result
in 35-45 tons of sediment
per acre per year
SOURCE: WeatherBuild

10. In addition to sediment, runoff can
include nutrients, heavy metals,
petroleum hydrocarbons and
harmful bacteria.

11. It’s usually easier and cheaper to prevent
erosion than control sediment from leaving the
construction site.
SOURCE: US EPA

12. Cost of soil erosion per ton
SOURCE D. Pimentel et al. 1995, SCIENCE, Vol.267:1117-1123. *Represents 1995 dollars adjusted for inflation.
Nutrients
$5.08/ton
Off-site impacts
$5.08/ton
Water
$3.39/ton
$5
$10
$15
Nutrients
$3/ton
Off-site impacts
$3/ton
Water
$2/ton
1995 dollars
2020 dollars*

13. Soils with good infiltration and permeability cut
stormwater runoff rates and volumes, reducing
sediment and nutrient loss.

14. That’s why compost use
tops other stormwater
management strategies.

15. Compost beats:
• Straw and tack
• Hydro-seeding/hydro-mulching
• Fiber mulch
• Silt fence
• Wood chips

16. Compare to wood chips

17. Compare soil loss reduction
Compost application
compared to bare soils
Compost application
compared to silt fence
Reduced soil loss
by 86%
Reduced soil loss
by 99%
Compost application
compared to hydroseeding
Reduced soil loss
by 38%
SOURCE: University of Georgia Extension

18. Compost functions
much like a coffee filter
to trap sediment and
pollutants.

19. Once incorporated into soil, compost can
increase filtration up to 125%.
SOURCE: UGA Cooperative Extension

20. Standards for erosion control compost
Compost blanket Compost berm
SOURCE: University of Georgia Extension

21. The importance of particle size
Fine compost penetrates soil surface and
increases infiltration and water-holding
capacity.
SOURCE: University of Georgia Extension
Coarse compost helps prevent splashing, is
less likely to be disturbed by rainfall and
runoff, and catches soil particles already in
motion.

22. The importance of moisture content
Drier compost absorbs more water and binds
more pollutants.
SOURCE: University of Georgia Extension

23. But compost
that is too dry is
difficult to apply.

24. Compost that is
too wet can be
more expensive to
buy and transport.

25. Ideal moisture content
for finished compost is
40-50% .

26. The importance of organic matter
Organic matter, the percentage of carbon-based
components, is a basic building block of soil.
SOURCE: University of Georgia Extension

27. Compost use increases
soil organic matter

28. A 1% increase in soil organic
matter results in 25,000
more gallons of available
soil water per acre
SOURCE: USDA Forest Service

29. The importance of pH
pH affects ion availability and impacts
adsorption or precipitation of some metals.
Increasing pH can lower accumulation of
metals in plant tissues. Shoot for pH levels
close to 7.0, except for acid-loving plants.
SOURCES: University of Georgia Extension
and Soil Amendments and Environmental Quality

30. The importance of soluble salt content
Salts affect the medium’s ability to conduct
electrical current, which impacts cation
exchange capacity and plant nutrition.
4.0 mmhos/cm is ideal for horticulture.
SOURCE: University of Georgia Extension

31. The importance of low inerts
“Inerts” are contaminants like glass, plastic
and metal. They can cause problems in
both processing and compost use. Don’t
exceed 1.5% by dry weight. Under 1.0% is
preferable.
SOURCE: University of Georgia Extension

32. The importance of nutrient content
Plants require nutrition. Compost delivers
both macro and micro nutrients and holds
them at the application site. Use less synthetic
fertilizer; reduce polluted runoff.

33. The importance of stability & maturity
Unstable and immature compost
can rob plants of nitrogen and
cause damage. Stable compost
will not generate odor or heat.
NSOURCE: University of Georgia Extension

34. Application rates – compost blankets
1-3 inches depth (135 to 400 cubic yards per acre)
depending on slope. Gradual slopes require as
little as 3/4 inch or 100 cubic yards per acre.
SOURCE: University of Georgia Extension

35. Mixture ratio – compost blankets
Recommended is a fine grade (1/4 to 1/2-inch
screen) mixed with coarse grade (2 to 3-inch
screen) at a ratio of 3:1.
SOURCE: University of Georgia Extension

36. Compost blanket absorption
SOURCE: The Soil & Water Connection
100%
80%
60%
40%
20%
80%
100%
4-inch rainfall event
3-inch rainfall event

37. 2-inch compost blanket runoff reductions
University study on construction site soils (disturbed, compacted sandy clay loam)
SOURCE: The Soil & Water Connection
100%
80%
60%
40%
20%
Runoff
volume
reduced
50% Peak
runoff rate
reduced
36%
Total
sediment
loads
reduced
80%
Nitrate-
nitrogen
loads
reduced
88%
Total and
soluble P
reduced
83%

38. Compare performance
SOURCE http://www.jswconline.org/content/60/6/288.full.pdf+html
Compost reduced runoff more over one year
than hydroseeding, by 33% and 8% respectively,
and reduced total cumulative runoff relative to
the control by 55% and 30% respectively.

39. Mixture ratio – compost filter berms
Recommended is a fine grade (1/4 to 1/2-
inch screen) mixed with coarse grade (2 to
3-inch screen) at a ratio of 1:1.
SOURCE: University of Georgia Extension

40. Construction – compost filter berms
Use where slopes exceed 4:1 gradient. Build
windrow-shaped berms 1-2 feet high and 2.5-4 feet
wide. Build trapezoidal berms 2 feet high, 2-3 feet
wide at the top and 4 feet wide at the base.
SOURCE: University of Georgia Extension
2.5-4 ft.
1-2ft.
2ft.
4 ft.
2-3 ft.

41. Compost filter socks
Various study findings:
• 50% greater flow-through rate than silt
fence without a reduction in sediment
removal efficiency
• Reduced parking lot stormwater TSS by
99%, chemical oxygen demand by 92%,
oil/grease by 74%

42. Compare cost per gallon stored
SOURCE: MMSD Green Infrastructure Plan

43. One product | Many benefits | Superior results
COMPOST WORKS

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