Bioengineering

The term “Bioengineering” causes some confusion, as in recent years it has been appropriated by the biomedical industry. Generally it refers to a group of activities where living and non-living materials are used to achieve an engineering goal.

It is a broad term encompassing many different techniques. Many of these were refined over thousands of years prior to being actively grouped together under the umbrella of “Bioengineering”. Others have been developed more recently as practitioners experiment with new ways to address environmental challenges.

Spraygrass offers bioengineering solutions and techniques that utilise organic (living and non-living) materials to achieve an engineering goal. Below are a few of these techniques.
Jute Meshing (Soil Saver)

Heavy woven jute mesh holds seed and soil intact on slopes, drainage ways and other areas of concentrated water flow, and aids in preventing erosion during rainstorms.

Jute mesh is a material that stays put and generally cannot be lifted by flowing water, wind or vegetation. Because of its mesh formation, vegetation has plenty of growing room.

As jute is a natural vegetable fibre, you get “built in” organic material which will decompose in time and enrich the soils at the rate of 5 tonnes per hectare. You get immediate protection from erosion in critical areas, as well as a unique mulch.

Jute mesh can be placed onto the area immediately after grading, and can be seeded, pegged and oversprayed with bitumen emulsion. It gives you the freedom to select a variety of grasses or ground covers that best suit local and climatic conditions.
After jute mesh is installed, its gives the job a neat finished look.

Organic Fibre Matting
This product is often referred to as a “blanket” and unlike Jute Mesh is a complete blanket usually made from Jute, Coconut Fibre or Coir. It is also available in several grades (thicknesses) depending on its intended use. The thinner variety is used for establishing grasses, whereas the thicker OFM is generally used as weed mats in Landscaping where after being placed on a garden bed or embankment plants are then planted into the mat.

Where grassing is the intended use the seed can be sown either under the mat before placing or into the mat when placed.

The thinner mat allows the grasses to grow through it providing protection to the soil against storm and tempest until the grasses are established.

Once grass is established, the OFM’s being totally organic eventually decompose returning valuable organic properties to the soil.

Synthetic Matting
There are a number of non organic mats and netting available that are made totally from synthetic materials. These are usually UV Stabilized and are specified for the more extreme situations where greater protection and strength is required to hold the soil together whilst grass establishes through them and in some cases they are placed so that they are covered with topsoil and then seeded over.

Without referring to generic names they are variously referred to as a polypropylene fibre mats, three dimensional mats or polypropylene netting.

In almost all cases these products are more expensive than the Jute and OFM’s and information on these are available on enquiry.

Sediment Control Logs (“Straw Wattles”)
The cylindrical shaped logs are made from Coir, Coconut or Straw. They are available in several different diameters depending on the end use.

They are particularly useful on steep slopes where they act as contour banks, and can be used along waterways where aquatic plants can be planted unto them, whilst at the same time are providing stability at the waters edge.

Further information is available on enquiry.

Extent of Work
The work included in this contract is as follows:
Jute meshing of catch drains and steep slope batters etc

Contractors Qualifications
Each tenderer shall submit documentary evidence of his proven ability to carry out this type of work. Such evidence shall include a list of similar projects satisfactorily completed together with a statement of the qualifications and/or experience of the personnel to be employed on the works.

Site Preparation
It is recommended that whenever possible, areas to be Jute meshed should be topsoiled. Wherever possible the area should be free of weed growth large stones or other debris leaving an even surface on which to lay the mat.

Operation

Steep Slope Areas. Greater than 3:1

  • On the steep slopes the mat is laid vertical to the slope.
  • The top end is buried in a minimum 150mm deep trench and pegged at 500mm centres.
  • Where joined the Mat must be overlapped at minimum 150mm
  • At the bottom end of the Mat, lap 150mm and staple at 500mm centres.
  • Where the laps join down the slope, pins should be at 500mm centres.

Placement of Jute Mesh in the Drains and General Flat Areas
Where one strip is laid:

  • The Mat is laid horizontally down the drain.
  • The top end of the Mat is buried in a 150mm deep trench and pinned down at 200mm centres.
  • One pin at 1 lineal metre intervals is placed down the centre of the drain and the outer edges stapled at 2 lineal metres intervals.
  • Each join to be overlapped at 150mm and pins placed at 200mm intervals across the join.
  • The outer edges of the mat to have pins at 2 lineal metre intervals.
  • Where mats join down the middle of the drain they must overlap 150mm and be stapled at 2 pins per 1 lineal metre intervals.

OPTIONAL

Bitumen Emulsion Application
After the Jute Mesh has been laid and application of slow breaking medium putting anionic bitumen emulsion at the rate of 0.5 litre per m2 of straight product is to be sprayed over the meshed area. In the more difficult slope and water flow areas this rate can be increased to 1 litre per m2.

Seed and Fertilising of the Area
Seeding and fertilising of the area can be carried out prior to the laying of the mat or after it has been laid prior to the application of Bitumen Emulsion. It has been common practice to seed after placement of the mat prior to the application of Bitumen. Placement prior to the laying of the mat can cause considerable disturbance to the seen bed whilst the mat is being laid.

Why Spraygrass?

Spraygrass applications and techniques are appropriate for:
• Road-side batters
• Dam sites
• Bridge approaches and abutments
• Factory and shopping complex sites
• Powerline construction
• Mining sites
• Golf Courses
• Land subdivisions
Spraygrass has been operational for over 45 years, demonstrating quality workmanship and commitment to our customers.
Spraygrass is dedicated to providing excellence in workmanship using the highest quality products available to create complete customer satisfaction. This is achieved through teamwork, which ensures all staff are part of the Company and motivated in the same direction of continuous improvement to achieve success in all they do, from the Managing Director to field staff