Geomembrane Tips for Small Reservoirs (Embung)

Geomembrane is a geosynthetic product that is impermeable. Geomembrane is generally used to line storage facilities so that liquids do not seep into embankment fill and the like, which makes geomembrane for small reservoirs (embung) a common application.

In general, geomembrane for storage facilities such as an embung (small retention reservoir) should be ≥ 1 mm thick. This is because geomembrane less than 1 mm thick is only used in areas that do not carry heavy loads or on small-scale projects.

Geomembrane Roll Sizes

The size of 1 roll of geomembrane varies with the thickness used. Here are the sizes for each thickness:

• 1 mm geomembrane: 7 metres x 210 metres = 1470 m2
• 1.5 mm geomembrane: 7 metres x 140 metres = 980 m2
• 2 mm geomembrane: 7 metres x 105 metres = 735 m2

When installing geomembrane in an embung, it follows the shape of the storage area, and anchor trenches of ± 2 metres can be made on each side to hold the geomembrane in position. When 1 roll does not cover the area, additional geomembrane can be joined by welding with a geomembrane welding machine and geomembrane welding rod.

After seaming, leak and strength tests are usually carried out. The seam strength must be better than that of the geomembrane itself. When lining a storage area, geomembrane can be laid once the ground is free of rocks or sharp vegetation that could puncture it.

Embung Dimensions

If there is still a risk of puncture from the ground, non-woven geotextile ≥ 200 GSM can be used. The non-woven geotextile resists punctures so they do not reach the geomembrane directly, reducing the risk of leaks.

Below is a simple design for installing geomembrane in a storage area:

Height, width and length can be adjusted to the needs and actual design on site. The geosynthetics are placed with non-woven geotextile on the soil, covered by geomembrane. The geomembrane area required generally needs an extra 10% for seam overlaps. PT. Petra Nusa Elshada geomembrane products are available as local products (with a TKDN local content value) and imported products.