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  Environment » Natural Resources » Land and soil » Erosion » Earthworks - erosion and sediment control

Earthworks - erosion and sediment control

Huntly Section of the Waikato Expressway under construction - April 2016
Huntly section of the Waikato expressway under construction
April 2016

Soil erosion is a natural process where gravity, wind and water wear away the soil surface. This process can be accelerated by activities like quarrying, earthworks construction and subdividing land. Find out how you can reduce your impact.

More on this page: erosion effects, guidelines and information, workshops and training

In the news

Sitelines - spring edition

Read the the most recent issue of Sitelines, our newsletter for earthworks contractors.

Sitelines: stable sites, healthy environment [PDF, 1.2 MB]

Winter 2017

The last couple of months have seen an unexpected amount of rainfall for this time of year, which has unfortunately reduced workable time for earthmoving. This has seen control devices failing, from what appears to be poor construction and not following best practice. It is important to take the learnings from these experiences as the level of control failures throughout the region have been very disappointing.

At all times, please ensure:

  • devices are constructed with the correct materials
  • keyed into natural ground level
  • built to Waikato Regional Council guideline and factsheet standards.

This will ensure controls should not fail, despite increase in rainfall.

The reduced workable time for earthmoving through March and April has been understandably frustrating for all, however this has in turn also led to poor decisions being made onsite which otherwise would not be considered. We understand how difficult it can be when the weather does not play nice, but please be guided by best practice and consent requirements always when considering what needs to be done. Just like health and safety, environmental monitoring and maintenance is everyone’s responsibility onsite.

Winter Works

One of the main issues that arises every year over the winter months is sediment being tracked offsite.

You will note that one of the requirements of your winter works approval, is to ensure no sediment is tracked offsite and that if it does, all works are to cease until such time as the issue can be resolved.

Having a wheel wash and a good quality stabilised entrance way will assist in keeping sediment onsite. However like all controls, these need to be closely monitored and maintained throughout

ANNUAL EROSION AND SEDIMENT CONTROL / EARTHWORKS EXCELLENCE AWARDS

Waikato Regional Council will again host the annual awards this August. These awards focused on sharing experiences and highlighting best practice consistently applied to sites throughout the region.

Waikato Regional Council will be requesting nominations soon for the award categories, which are as follows:

  • Large sites (i.e. large scale roading projects and large subdivisions.)
  • Medium sites (these are generally the most consented sites, subdivisions, council roading projects, or industrial developments.)
  • Small sites (these can be permitted activity sites, small scale subdivisions and culvert replacement works.)
  • Innovation (things that have worked, things that haven’t, differences onsite, outside the scope of general ‘run of the mill’ erosion and sediment controls.)
  • Forestry (Best practice, stabilisation and environmental outcomes on forestry sites that are often difficult to achieve.)

This award recognises those companies that exceed the “norm” and show best practice and/or innovative measures.

ANNUAL EROSION AND SEDIMENT CONTROL WORKSHOPS

The workshops are open for bookings and will run through July and August this year. As with previous years, the practical workshop includes a visit to a working site to view the controls ‘in action’. Both the practical and planning workshops are filling quickly, so please hop online and register your attendance, at the bottom of this page.

As always if you have any queries around earthworks, please talk to the monitoring officer undertaking the site inspections, or feel free to give me a call.

Lorraine Dunmall

Erosion effects

Each year in the Waikato region, large areas of land are stripped of vegetation or laid bare because of construction or operating of quarries, subdivisions, roads, cleanfills and other developments. Without appropriate erosion and sediment control, these activities can result in accelerated on-site erosion and greatly increased sedimentation of waterways, lakes, estuaries and harbours.

Various studies show earthworks sites may produce 10 to 100 times more sediment yield compared with pastoral land, and 1000 times more compared with permanent forest cover.

Sediment can damage our waterways’ ecology by:

  • modifying or destroying instream, estuarine and coastal values (such as water quality and habitat)
  • affecting aquatic animals and plants due to:
    • smothering
    • changes in food sources
    • interruptions in lifecycles.

These damaging effects often totally change instream communities. Recovery from the impacts of sediment deposition is slow - years rather than months.

As well as ecological changes, sedimentation may:

  • damage water pumps and other structures
  • reduce domestic water quality
  • spoil an area’s appearance
  • affect the spiritual and cultural values that tangata whenua associate with a waterbody.

Best practice Decanting Earth bund - March 2016 (photo taken by Fulton Hogan/HEB Joint Venture)

Image: Best practice Decanting Earth bund - March 2016 (photo taken by Fulton Hogan/HEB Joint Venture)

Resource consents

A resource consent may be required from the Waikato Regional Council if your activity will involve soil disturbance near streams, lakes, wetlands or coastal waters, or where the works are on steep land.

Consents also may be required for stormwater discharges from these sites. Soil disturbance, roading, tracking or vegetation clearance projects that don’t require consents are called ‘permitted activities’, and these require compliance with specific conditions.

Find out more about resource consents (including application forms), or call the Resource Use Freephone on 0800 800 402.

Guidelines and information

For technical support and access to the spreadsheet to assist in ensuring that sediment retention ponds and culverts are sized correctly, please refer to this webpage www.mcconnellconsultancy.co.nz (external link) .

Erosion and sediment control guidelines for soil disturbing activities (2009) 

You can download ‘Erosion and Sediment Control – Guidelines for Soil Disturbing Activities’ via the above link. 

Please note the following sections are no longer relevant, and you will need instead to refer to the corresponding fact sheets:

  • 3. Sediment Control Practices
  • 3.1 Sediment Retention Pond
  • 3.2 Silt Fence
  • 3.4 Hay Bale Barrier (these are no longer considered suitable control devices)
  • 3.6  Decanting Earth Bund

Factsheets

Decanting earth bund (181kb)

Sediment retention pond (355kb)

Stabilised construction entrance(64kb)

Small site sediment control

Catchpit protection (146kb)

Concrete and asphalt (193kb)

Silt fence (160kb)

Silt sock / filter log (163kb) - Now includes additional controls

Sediment Control Brochure (external link) - Hamilton City Council

Erosion and sediment control plan preparation guideline

Almost every site will require an erosion and sediment control plan (ESCP).

The guideline below will help you prepare your ESCP. Use these guidelines when planning your earthworks project to develop an erosion and sediment control plan, and to prepare your project’s resource consent application if one is required. Note that granted resource consents will most likely require compliance with these guidelines. The guidelines should be used as best practice on permitted activity sites as well.

Erosion and sediment control plan preparation guideline (1mb)

Image of earthworks at Huntly power station.Winter works guideline

Most resource consents will require works to stop between 30 April and 30 September, unless written approval is obtained from the Waikato Regional Council.

This guideline is to assist you with making your application to continue works through the winter works shut down period.

Winter works application preparation guideline (433kb)

Pre-construction meeting checklist

Most resource consents will require a pre-construction meeting with relevant parties involved in the project.

The checklist below will assist you with topics to discuss and agree upon with the Waikato Regional Council representative prior to commencement of works.

Pre-construction checklist [PDF, 86 KB] - You can edit directly into this PDF (you might need to check or update your software to do this - you'll need Acrobat Reader (external link) ). Make sure you save it out to your desktop before you start editing, if you start editing in the original version on this webpage, your changes won't save.

As-built certification sheets

Most resource consents will require ESCs to have as-builts undertaken, and to be certified that they have been constructed in accordance with the approved ESCP or Waikato Regional Council's erosion and sediment control guidelines

These sheets are to assist you with the information required for the as built certifications.

Download the sheets below:

Sediment retention pond (SRP) (518kb)

Decanting earth bund (DEB) (505kb)

Silt fence / Super silt fence (SF/SSF) (504kb)

Diversion channel / Diversion bund (DC/DB) (521kb)

Workshops and trainingPhoto of best practice demo during ESC workshop day 

The Waikato Regional Council offers workshop training opportunities for the earthworks industry.

Practical erosion and sediment control

A one-day workshop with a practical focus on constructing erosion and sediment controls. This workshop covers best practice erosion and sediment control methods in accordance with the Waikato Regional Council's Erosion and Sediment Control Guidelines, Waikato Regional Plan requirements and legal obligations under the Resource Management Act 1991 (RMA). This workshop also includes a visit to a working site to view controls in the field.

Planning erosion and sediment control

A one-day advanced workshop with a practical focus for preparing erosion and sediment control plans and tips to assist with preparing land use resource consent applications. This workshop will cover the Waikato Regional Plan's rules relating to soil disturbance activities, and will include practical exercises in preparing an erosion and sediment control plan and site risk analysis.

Prerequisite to this workshop: Participants must have previously attended the practical erosion and sediment control workshop or the previous two-day planning erosion and sediment control workshop.

Registrations are still open for this year's workshops.

Complete an online form, below, to register. When you submit your online registration form, it will be sent directly to Nikki Wall in our Resource Use Directorate.  If you've got any questions about the workshops, please call Nikki on 07 859 2718.

PRACTICAL erosion and sediment control

Date: Wednesday 23 August 2017

Time: 8am – 5pm

Venue: Hamilton Airport Hotel and Conference Centre, Airport Road, Hamilton

Cost: $450 excluding GST

>> REGISTER FOR THIS WORKSHOP

PLANNING erosion and sediment control

Date: Thursday 10 August 2017

Time: 8am – 5pm

Venue: Hamilton Airport Hotel and Conference Centre, Airport Road, Hamilton

Cost: $420 excluding GST

>> REGISTER FOR THIS WORKSHOP

About the facilitator

Peter StevensPeter Stevens - PS Environmental Services Ltd

Peter has 14 years’ experience in erosion and sediment control and resource consents. Since establishing his company in 2006, Peter has worked with a range of clients including regional councils, developers and contractors. Construction projects he’s worked on include subdivisions, state highways, roads, tracks, cleanfills, forestry conversions, hydro-electric power schemes, wind farms, bridges, stream diversions and quarries.

Peter has extensive experience in erosion and sediment control plans, resource consent applications and compliance monitoring, and provides erosion and sediment control training and advice for organisations both in the private and public sectors.

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