Coastal erosion can cause the erosion of land areas due to seawater. This poses risks, especially if the area is used for tourism or as a protected zone.
Some solutions have been implemented using concrete. However, this method requires more time and is slightly more expensive. Therefore, there is an alternative solution that can address this challenge more quickly and affordably: using geobags.
This article will discuss in detail the functions of geobags for coastal protection (erosion control and wave breakers), and is suitable for project contractors or coastal tourism managers who require a faster and more affordable coastal protection alternative.
Applications and Functions of Geobags for Coastal Protection
Geotextile bags or geobags are bags made from non-woven geotextile material and sewn using D9 nylon thread.
D9 nylon thread is a type of thread that is extremely strong and durable, particularly suited for coastal areas frequently exposed to waves and prone to tearing.
Generally, geobag sacks are filled with sand, soil, gravel (sirtu), and used to prevent erosion on riverbanks, seawater abrasion, wave breakers, as well as slope protection or stabilization.
For coastal geobag applications, they are filled with sand. The type of sand can be either seawater sand or land sand, depending on your project needs and budget.
If you want a cheaper option, you can use black inland sand, which is different from sea sand, which is cream or light brown in color.
This is cheaper because there is no need to obtain the material from elsewhere. However, if geobags use sea sand, you must obtain permission to obtain it, and the cost is not cheap.
Geobags make maintenance easier if they are damaged by waves. They are also easier to disassemble and reassemble in the future.
Geobag Sizes and Specifications for Coastal Protection
In the market, there are various examples of geobag sizes and specifications for coastal protection, such as 50 cm x 70 cm; 1.45 m x 2.4 m; 1 m x 2 m; and so on. The material used is polypropylene (PP) or polyester (PET). However, if used for seawater abrasion protection, the suitable material is polypropylene.
For geobags made of 600 gsm polypropylene, measuring 1.45 m x 2.45 m, the weight of the geobag without sand is approximately 4.26 to 4.5 kg/piece, and the weight increases after being filled with sand.
With this size or larger, it is suitable for withstanding large waves and continuous frequencies.
Sand filling is done to 80% of the geobag’s volume to prevent excessive load and seam rupture. The geobag size can be adjusted to change its dimensions if the load is too heavy.
For smaller waves, geobags of 50 cm x 70 cm or 40 cm x 60 cm can be used.
Referring to the previous explanation, the size and specifications for coastal protection such as wave breakers and seawater abrasion barriers must meet the appropriate criteria for their intended use. The specifications for Urban Plastic geobags are as follows:
Size: 1.45 meters x 2.4 meters (customizable)
Grammage or thickness: 600 gsm
Material: Polypropylene (PP)
Advantages:
Very strong and tear-resistant.
UV-resistant for 5–10 years or more, depending on conditions, geobag filling material, and installation method.
Durable for long-term outdoor use, such as on beaches.
Easy to install and use for coastal protection.
Geobag Installation Method for Coastal Protection
First, you need to clean and level the beach area where the geobags will be installed.
Second, the use of geobags should be tailored to the specific needs of your project. Geobags are filled with sand, ensuring that the filling reaches at least 80% of the total volume of the geobag. This prevents the geobag from becoming too full, which could make it prone to damage and cause the seams to come apart.
Third, the sand filling in the geobag is protected by sewing the open part of the geobag using D9 nylon. D9 nylon is strong and elastic, especially in coastal areas frequently exposed to wave impacts.
Steps two and three can be skipped if the geobag is ordered pre-filled with sand and already sewn by the supplier or manufacturer, in which case you can proceed directly to step four.
Fourth, after preparations have been made, arrange the geobags neatly in the area you have determined using a tiered arrangement pattern.
You must ensure that they are neatly arranged with the soil and other geobags beside or above them. If necessary, tie the geobags together with rope to make them more secure.
Fifth, the final step, which is important but often overlooked, is regular inspection and repair or replacement of geobags if they become worn due to prolonged exposure to sunlight and chemicals, or if some are damaged by frequent wave impact.
Tips and Best Practices for Selecting Geobags for Coastal Erosion Protection
When selecting the size and specifications of geobags for coastal protection, it is important to consider project requirements and several key factors, including:
Material Composition
What materials are used, such as polypropylene (PP) or polyester (PET). If placed directly in contact with seawater, polypropylene is recommended due to its UV resistance, which helps prevent damage and extends the geobag’s service life.
Grammage or Thickness
Geotextile bags (geobags) typically have a grammage ranging from 400-600 gsm. For erosion control and wave breakers on beaches, it is recommended to use a grammage of 600 gsm.
This thickness is more resistant to tears and extreme weather conditions, particularly exposure to sunlight.
In addition to the grammage, you can customize the geobag to suit your project needs, as done by Urban Plastic Company.
Size
The standard size of a geobag is 2.45 m x 1.45 m with a volume of approximately 1.4 m³. However, this size can vary depending on your project requirements.
Durability and Elasticity (Tensile Properties)
Geobags must be resistant to UV rays, chemicals, and pressure from sand or filling materials. They must also have optimal elasticity (tensile strength) when subjected to pressure, such as from ocean waves, to prevent tearing.
Seam Quality
The seams on geobags must be strong and meet established strength standards. Geobags sewn with D9 nylon thread using a double-needle lockstitch machine ensure that the sand filled into the geobag and sewn will not leak out.
Geobag Prices for Abrasion Protection and Wave Break
Geobag prices vary in the market, depending on the materials used, geobag size, customization requirements, and other factors.
If you are looking for a geobag supplier or provider to consult in detail about technical specifications, geobag sizes, installation methods for special cases, and geobag prices, Urban Plastic offers fast, affordable, and sustainable solutions.
For more information about Geobag please contact: Whatsapp/Mobile Phone: +62 811 9151 338 (Ms. Anna) or Email :info@baligeotex.com