Benefits of Using Compost for Erosion and Sediment Control

The following article was written recently by a colleague in the US [ Ron Alexander] and some content needs be seen in the context of that general location.

However, the broad implications are still relevant and even more so in the tropics with normally much greater intensity of rainfall, in comparison to temperate areas.  The experience of our own operations in the tropics on very large mining projects in Indonesia and tropical Australia adds to to the ideas written below here by the author, with surface applied mulches and composts being excellent erosion and sediment management options, even on slopes up to 1:1 - ie 45 degrees. Much better than silt fences!!

We even used chipped coconut husk pieces on some steep slopes very successfully, but commonly in Indonesia we used rice straw, a nominally waste material supplied by local farmers rather than burning it as waste in the fields after threshing the grain.  It was excellent, as mucous exuded from the straw helped bind the material together, allowing permeation of water through but not necessarily washing it all away.

Yes.......we needed some rechecks and repairs but for a very large area of bare slopes it was excellent, and certainly reduced erosion enormously at relatively low cost.

Mulch berms are now also commonly used on larger flat exposed areas near Darwin, with more extensive use on several large mining, construction and building projects in recent years.  Definitely a go to option that works well, is easily repaired when needed and it can tolerate heavy tropical rain, reducing high intensity overland flows.

Surface applied mulches can be very effective - consider them as a sensible option for your next erosion and sediment management project.

We offer ESCP plan development for projects and can assist you develop an appropriate solution. 
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9 Benefits to Using Compost for Erosion and Sediment Control

by Ron Alexander  8 January 2016

Credit: Erth Products

Erosion and sediment control. Although still considered relatively unknown in certain regions of North America, the use of compost in erosion and sediment control has been a very successful landscaping practice for over 25 years. 

Compost blankets (the application of a layer of compost on hill slopes), compost berms, and compost filter socks are incredibly effective, enhance the long-term quality of the soil, and, in the case of compost blankets, have excellent stormwater reduction advantages. These innovative techniques have been thoroughly proven through university research, and have been recommended for use by the USEPA. 

National specifications exist for these applications through the American Association of State Highway and Transportation Officials. (Go to www.alexassoc.net, then “Library of Articles,” and look under “Compost Specifications” to see the full specs.)

When used as a compost blanket, compost is typically placed on up to 2:1—and sometimes more severe—slopes at an application rate of 1–2 inches [25-50mm] in depth. 

This technique is used and is highly effective in reducing and slowing the sheet flow of water. 

Lesser application rates are possible in areas of lower rainfall accumulation and intensity, on less severe slopes, and where vegetation is to be established. Once applied, the woody fraction of the compost increases surface roughness and slows the flow of runoff, thereby making it less erosive, more likely to induce infiltration into the soil and reduce the transport of pollutants. 

In addition, the woody fraction absorbs the energy of the rainfall, preventing soil particles from dislodging (the first stage of soil erosion), while the finer fraction beneath it absorbs a substantial volume of moisture, and is optimum for plant establishment and growth. Research completed at University of ­Georgia illustrated that a 2-inch[50mm] application of compost onto a slope could absorb and hold 1–2  [50mm]inches of rainfall.

Further, the unique properties of the product allow for extensive rooting of the grass and other vegetation, locking the blanket to the slope and protecting the soil beneath it. 

It should also be noted that compost blankets are effective with or without vegetation, but application rates of compost can often be reduced if it is applied with vegetation. University research consistently illustrates that compost blankets not only constantly outperform hydroseeding and conventional erosion control blankets (e.g., rolled fabric) in vegetation establishment, but also more effectively reduce stormwater runoff volume and peak flows, as well as total sediment and nutrient loads (Faucette et al. 2005; Faucette et al. 2007; and Faucette et al. 2009, “Large-scale performance and design…”).

Research performed for Portland Metro, an environmental regulatory body based in Portland, OR, and the USDA ARS further illustrated that yard trimmings compost was capable of not only controlling erosion, but also of filtering, binding, and degrading contaminants from the stormwater passing through the layer (Faucette et al. 2013; Faucette et al. 2009, “Storm water pollutant removal performance…”).

The benefit of using a compost blanket lies in its ability to:

• act as a buffer to absorb rainfall energy,
• reduce wind and water erosion,
• stimulate microbial activity to increase decomposition of organic materials in the soil thereby adding to the soil structure,
• prevent soil compaction and crusting, thereby facilitating percolation,
• slow the flow of water over the surface of the soil,
• capture and retain moisture, reducing soil moisture loss thereby facilitating plant growth,
• provide suitable microclimate for seed germination,
• in areas with cold winters - capture blowing snow to increase the insulating effect of winter protection, and
• improve soil texture (Story et al. 1995).

Compost berms and filter socks are “3D” filters possessing huge sediment and biofiltration capabilities. 

Where the berms are used in sheet flow conditions, the filter socks (think pantyhose filled with coarse compost) can also be used in concentrated water flow situations. 

This is because filter socks can be staked into place, and the compost media is contained within a mesh netting material. 

Although both compost berms and filter socks are used as perimeter control devices for sediment, installed around the borders of construction sites and at the top and bottom of slopes, the filter sock technology is much more versatile (see www.filtrexx.com). 

They can even be used around stormwater inlets and to build “living” walls. 

One of the most important research findings pertaining to compost filter berms and socks, is that they are much more effective in capturing fine particles of sediment, which are not captured as efficiently by other more conventional sediment control devices (e.g., silt fences). 

This is very important in that fine particles of sediment have the potential to be much more damaging to the environment, since they transport further and stay in suspension longer, and also contain a greater amount of chemical contamination (e.g., petroleum hydrocarbons, heavy metals, nutrients) than larger particles of sediment.

The use of compost in erosion and sediment control projects has expanded significantly since the adoption of the National Pollutant Discharge Elimination System (NPDES) Phase II regulation for construction activities in the USA. 

This regulation requires that construction sites of 1 acre or greater to have erosion and sediment control plans in effect on a daily basis using prescribed best management practices (BMPs).

Composting - Vital for Better Soil Health, Fertility and Reducing Erosion

Composting reduces waste and builds healthy soil to support local food production and protect against the impacts of extreme weather, from droughts to heavy rainfall. That’s the message of two new reports from the Institute for Local Self-Reliance (ILSR):

State of Composting in the U.S.: What, Why, Where & How <http://www.ilsr.org/state-of-composting/> and

Growing Local Fertility: A Guide to Community Composting<http://www.ilsr.org/size-matters-report-shows-small-scale-community-based-composting/>

Compost is the dark, crumbly, earthy-smelling material produced by the managed decomposition of organic materials such as yard trimmings and food scraps. Compost is valued for its ability to enhance soil structure and quality. It adds organic matter to soil, improves plant growth and water retention, cuts chemical fertilizer use, and stems stormwater run-off and soil erosion. In the U.S., 40 million hectares (28% of all cropland) are eroding above soil loss tolerance rates, meaning the long-term productivity of the soil to support plant growth cannot be maintained.  

It might be worse comparatively in Australia, and China certainly has major problems!

compost production- commercial scale

Applying a meagre 12mm of compost to the all of the severely eroded cropland in the USA would require about 3 billion tonness of compost,” says Brenda Platt, the lead author of both reports and director of ILSR’s Composting Makes $en$e Project. “There is not enough compost to meet that need.  No organic scrap should be wasted.”

Compost also protects the climate:  it sequesters carbon in soil and it reduces methane emissions from landfills by cutting the amount of biodegradable materials disposed. (Methane is a greenhouse gas with a global warming potential 72 times more potent than CO2 in the short-term.) A growing body of evidence demonstrates the effectiveness of compost to store carbon in soil for a wide range of soil types and land uses.

Yard trimmings composting programs are fairly well developed in the U.S.

Of the 4,914 composting operations identified in the U.S. for State of Composting in the U.S., about 71% compost only green waste / yard trimmings (based on 44 states reporting). Food scrap recovery is slowly growing. More than 180 US cities and counties are now collecting residential food scraps for composting, up from only a handful a few years ago.  “There is more demand for composting, especially from businesses and institutions that want to source separate food scraps and not throw them in the landfill,” says Nora Goldstein, Editor of BioCycle, which conducted the state-by-state assessment of composting infrastructure and policies, “We not only need more infrastructure to compost these materials, we need more infrastructure to manufacture high quality compost that our soils — and climate — desperately need.”

 

compost berm used in erosion control

State of Composting in the U.S. is the first comprehensive review of composting basics, national and state statistics, job generation data, model programs, and policy opportunities.

The report calls for a national soils strategy and for new rules and programs to grow composting, especially at the local community level: including streamlined permitting for facilities, training programs, technical and financing assistance, strong recycling and composting goals, disposal bans, compost procurement policies, and more.  “The beauty of composting is that it can be small-scale, large-scale and everything in between,” says Brenda Platt. “Why send resources out of the community when our neighbourhoods need food and our soils are starved for organic matter?”

I would imagine that the report for Australia and the NT in particular would be quite similar.  However, around Darwin mulched green waste is widely used in domestic areas but much less so commercially and for landscape rehabilitation where it can be especially useful in restarting organic processes on damaged soils.

A sneak peek inside State of Composting in the U.S.: What, Why, Where & How:

·      Section 1, What Is Composting and Compost, describes the composting process, what materials can be composted, composting systems, and the many uses for compost.

·      Section 2, Why Compost?, identifies the key benefits of composting to create jobs, protect watersheds, reduce climate impacts, and improve soil vitality.

·      Section 3, Where Is Composting Happening, provides a national snapshot of composting infrastructure, current policies, and model programs that could be replicated.

·      Section 4, How to Advance Composting, outlines new rules and initiatives to grow composting, and describes the importance of a diverse and locally based infrastructure.

ILSR’s companion report, Growing Local Fertility: A Guide to Community Composting, features successful community-scale composting initiatives, their benefits, tips for replication, key start-up steps, and the need for private and public sector support. 

Produced by ILSR’s Composting Makes $en$e Project and the Highfields Centre for Composting, this guide highlights more than 30 diverse urban and rural small-scale locally based composting programs in 14 states and the District of Columbia.  They include schools, pedal-powered collection systems, worker-owned cooperatives, community gardens, and farms employing multiple composting techniques.

To download both reports, visit  www.ilsr.org/initiatives/composting

Compost Berms for Erosion and Sediment Management

Traditionally erosion and sediment control seems to have started and stopped with using a silt fence.

Experience in the tropics often seems to indicate that silt fences may not be the solution that is best suited to these conditions.  They often are poorly constructed, commonly with poor insertion of the tail into the ground.  The intensity of rain commonly dislodges soil particles and along with a lot of water these fines clog the fence.  Common result is a failed fence.  Not to mention the need for a lot of maintenance.  They have a place – but there are smarter options.
Mulch and compost berms are gaining a lot more credibility in many seasonally wet tropical regions as a superior option to provide erosion and sediment management.  If you have tried them out………they are worth considering.

That is particularly true in north Australia where copious volumes of green waste are dumped at local landfill sites and then ground up at many of the regional towns and cities, to produce mulch.  This material is commonly then given at least a partial pasteurisation in a stacked row, and reused for garden mulch.  As well as garden mulch – it is ideal for building small mulch / compost berms that can provide excellent erosion and sediment management on construction sites.

The berms can be built with readily available machinery, or if available a mulch blower.

There are a range of on line resources available to help you gain more understanding, and the concept is strongly recommended by the US EPA as well as many other organisations.

http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=min_measure&min_measure_id=4

This link is to the US EPA site with many links to a range of construction site tools of which compost filter berms are but one………albeit very useful.

The next link is to an article where berms are compared to silt fences in the USA.  The article is over 10 years old, but mostly still relevant.  There are many advocates for the use of mulches but read about it yourself.

http://www.tceq.state.tx.us/assets/public/assistance/compost/compost_silt_fence.pdf
The article is a good overview of using berms.

And the trees or vegetation often removed for construction can also be utilised to reduce sediment and erosion – even laid in a simple matrix on the ground, with plenty of leaves and small branches inter mixed with larger branches.  It is a smart idea, a simple easy option to reduce erosion problems.