Method Statement -Hydroseeding

1.0 OBJECTIVE

This Work Method Statement is to outline the sequence of activities, method and resources needed for the operation of hydroseeding works.

 

2.0 SCOPE

This method statement shall apply for hydroseeding works for (yor project name). Details of the procedures contained herein may be modified based upon actual ground condition and site requirements.

 

This works shall consist of slope surface preparation and hydroseeding work including supply of all necessary equipment, manpower and materials on location of slopes in cut and fill areas as shown in drawings or as directed by the S.O.

 

3.0 REFERENCES

Ø  Construction Drawings

Ø  Project Specifications

 

4.0 DEFINITIONS

       -Nil

 

5.0 RESPONSIBILITIES

Ø  Safety Officer/Supervisor

Ø  Site Manager

Ø  Project Engineer

Ø  Site Supervisor

 

6.0 MATERIALS

Material to be used is as follows :-

Ø  Paper mulch

Ø  Latex

Ø  Fertilizer – NPK 15:15:15

Ø  Grass seed – Urochloa Decumbens

 

7.0 HANDLING AND STORAGE OF MATERIALS

Handling - Transport of materials shall be carried out by lorry or other suitable machinery.

Storage – Covered and raised above floor level.

 

8.0 PLANT, MACHINERY AND EQUIPMENT

Ø  Lorry

Ø  Water tank

Ø  Spray pump machine

 

9.0 PREPARATORY WORK

9.1 Possession of site                                                                                     

Ø  To take photographs of the designated area.                                                                               

Ø  To arrange joint inspection between the contractor, consultant and client representative, in certain cases may involve.

 

9.2 Hydroseeding 

Ø  Hydroseeding shall be carried out as soon as practicable on slopes and other areas as shown in the drawings and/or directed by the S.O. 

Ø  Unless otherwise approved by the S.O., hydroseeding shall be carried out within 14 days after the slope is cut or filled.

Ø  The surface before hydroseeding shall be free of loose or soft materials.

Ø  Cut slope surface shall have some horizontal grooves (about 20mm deep) at about 200mm intervals.

Ø  Vertical grooves shall be avoided.

 

9.3 Signal Grass ( Brachiaria Decumbens / Urochloa Decumbens )

Ø  Signal grass is indigenous to Uganda and is currently being grown in many tropical to subtropical countries throughout the world. 

Ø  Many Brachiaria species including Brachiaria Decumbens have been placed by some authors in the Urochloa genus, so the taxon Urochloa Decumbens is often considered as the correct.

Ø  It forms a dense, high yielding sward which response very well to additional nitrogen.

Ø  It is a perennial grass with strong stoloniferous roots system and long trailing stems which will readily root down from their nodes.

Ø  Signal grass is highly recommended for slopes erosion control and is widely used along most of our Malaysian highway including the North South Highway.

Ø  Originally, Signal grass was mainly used in the wet, humid tropics but in recent years, is being grown over much wider climatic conditions.

 

9.4 Component of Hydroseeding

Ø  Lorry

Lorry with a 350 gallon capacity of water tank and others machineries for hydroseeding and watering purpose.

Ø  Labour

Each lorry has one (1) driver, one (1) assistant and 2 (two) workers to conduct the spraying of mixtures which has been premixed.

Ø  Raw Material

·         Paper mulch

Paper mulch provides a mat which follows the contour of the soil and keeps the seeds in moist condition for faster germination. Eventually, the mulch decomposes serving as humus which further improves soil condition.

·         Latex

·         Fertilizer (15%N, 15%P, 15%K)

·         Grass seed (Urochloa Decumbens – Signal grass)

 

9.5 Proportion of mixing

Ø  Paper mulch – 45kg

Ø  Latex – 20kg

Ø  Fertilizer – 20kg

Ø  Signal grass seed – 10kg

Ø  The mixture is measures based on the capacity of a 350 gallons of water tank.

Ø  The mixture can cover approximately 500m2 to 700m2.

                        

10.0 WORK METHODOLOGY

Ø  Grass seed and other raw material ( Paper mulch-45kg, Latex- 20kg, Fertilizer-20kg, Signal grass seed-10kg ) are measured and mixed with water in a tank (350 gallons). The various raw materials are then mixed in a tank for about fifteen (15) minutes to ensure a uniform mixture. This mixture is now in a semi-liquid state or slurry.

Ø  The team leader control the outlet of the flexible hose during the spraying of the mixtures on the slopes. One of the assistants shall be stationed at the pimp in order to monitor or control the pressure of pump, while the other two (2) workers shall be responsible for laying of flexible hose during the spraying process.

Ø  The spraying should be done in the uniform pattern in order to ensure even coverage of slurry of soil surfaces.

Ø  Hydroseeding should never be applied during, before or immediately following rainfall as well as during high wind.

Ø  Machines and tools should be flushed and cleaned with water immediately after use.

Ø  Under the normal soil conditions, the germination would take about 7 days to 9 days.

Ø  For the hydroseeding on cutting area and when the grasses grow about 2 inch – 3 inch, fertilizer in liquid form is spray on the hydroseeded area in order to ensure speedy growth and uniform germination.

Ø  If the grasses do not growth satisfactory, a second spray of liquid form fertilizer would be carried out.

Ø  At the filling area, solid fertilizers are manually applied on the hydroseeded area.

 

11.0 MAINTENANCE PROCESS

Ø  To cut the hydroseeding prior to handing over not more than one third of the blade at any one time and ensure no overcutting resulting in bare or brown patches.

Ø  After one (1) month, the supervisor shall conduct a site checking on the hydroseeding area. If the grass does not grow satisfactorily or do not grow due to various site conditions, a reseeding process shall be carried out for the same area.

Ø  However, we shall not be liable for re-hydroseeding if soil erosion, landslide and etc that may affect the growth of grass.

Ø  In addition, where the material is rocky or toxic to plants, the growth is not guaranteed.

 

12.0 TRAFFIC MANAGEMENT AND MONITORING

12.1 Maintenance of existing roads, footpaths and service drains, etc.

Ø  The construction team shall maintain all existing site excess, roads, footpath, service drain, etc. and reinstate any damage caused by any reason whatsoever during the progress of the works.

Ø  It will be the Safety Officer/Supervisor’s responsibility to ensure that ingress and egress to the site are kept free from obstruction brought about by the work on this site and in no way shall cause hindrance to traffic or ancillary works either by his own vehicles or by his work people, material, etc.

 

13.0   SAFETY PROGRAMME

13.1    Temporary Works and Public Safety

Ø  The Safety Officer/Supervisor shall be responsible for submission of plans and drawings to the relevant Authorities for the construction of all the necessary temporary drains and desilting pits, safety nettings for the works. 

Ø  The Safety Officer/Supervisor shall provide adequate signboards at all strategic positions warning the public to keep away from the work site and erect temporary fencing and barriers where necessary around the site to prevent unauthorized trespassing during works.

 

14.1    ENVIRONMENTAL PROGRAMME

All works should be carried out in accordance to best practice environmental management as defined in the EMP.

 

14.1    Site Access.

Ø  The access as well as the portion of public road and walkway connected with it shall be always kept clean and safe.

14.2   Temporary Work.

Ø  Existing drain shall be identified by contractor together with the flow of drain until discharge point in order to make use of it during clearing work. Silt trap shall be provided before any discharge of surface water within site towards existing drain. This work should be completed prior to the commencement of any activities.

Ø  Temporary earth drain shall be constructed along clearing area to retain the surface water from dismissal directly towards existing drain. Desilting work shall be carried out regularly and the existing drain will be maintained during work.

Ø  Any effluent discharges from the site must comply with the Third Schedule of the Environmental Quality (Sewage and Industrial Effluents) Regulation 1979.

14.3   Waste Management.

Ø  Any construction wastes, solid wastes and domestic wastes other than schedule wastes must be disposed-off at the approved disposal site. On site compositing for biodegradable waste is allowable but land filling and open burning activities for the solid waste are strictly prohibited.