Process Water Storage Reservoir — Earthwork & HDPE Lining

A reservoir that leaks is not storage. It is a slow, expensive way of putting treated water back into the ground.

Geotech Design Consultants provided engineering consultancy for a water storage reservoir supporting process-water management at a Coca-Cola facility. The requirement was a reliable, cost-effective storage solution that would integrate with the plant's existing water-management infrastructure while providing secure containment and minimising losses through seepage.

Given the industrial application and the importance of storage reliability, an engineered earthwork reservoir with HDPE geomembrane lining was adopted as the principal solution — earthwork to create the storage geometry, geosynthetics to hold the water in it.

The reservoir had to provide adequate process-water storage while maintaining long-term hydraulic containment and operational reliability — three requirements that pull in different directions if handled separately. It had to be configured within the available site area, with suitable formation levels, side slopes and embankment geometry, giving the HDPE liner a stable foundation while remaining practical to construct and maintain.

And it had to stop seepage. Conventional unlined earth reservoirs can lose a significant volume of stored water into the underlying soil depending on ground conditions — a continuous, ongoing loss of water the plant has already paid to obtain and treat. A low-permeability engineered lining system was therefore required, not an optional enhancement.

The liner was never treated as an independent component laid on top of finished earthwork. Geotech Design Consultants assessed the site requirements and developed an integrated earthwork and geosynthetic containment solution. The reservoir was designed as an engineered earth structure, with excavation and embankment formation carried out to achieve the required storage capacity and hydraulic geometry.

Slopes and formation were developed to provide a suitable surface for geomembrane installation while accounting for stability, constructability, drainage and long-term liner performance. Every earthwork decision was taken with the liner in mind, and every liner detail was drawn against the earthwork that would carry it — one continuous containment system, designed as such.

The earthwork establishes the storage geometry and the foundation the lining system depends on. Engineering considerations covered reservoir capacity, excavation levels, embankment formation, side-slope configuration, crest arrangement, freeboard, access and surface preparation.

The principal containment element is an HDPE geomembrane: a low-permeability barrier between the stored process water and the underlying soil, substantially reducing seepage and improving storage efficiency. Installation was developed around panel layout, welding and jointing, anchoring, slope transitions, corners, penetrations and termination details, with the liner integrated into the earthwork to form a continuous water-retention barrier. Where site conditions and construction methodology require it, a geotextile protection layer can be incorporated beneath and/or above the geomembrane to protect the HDPE from mechanical damage.

A typical section reads, from the ground upwards: compacted and prepared earth subgrade → protective geotextile layer, as required by design → HDPE geomembrane → process water. The actual geosynthetic specification is finalised against site conditions, storage requirements, subgrade characteristics and project specifications.

1. 01Process WaterSTORED VOLUME
2. 02HDPE GeomembraneCONTINUOUS BARRIER
3. 03Protection GeotextileWHERE REQUIRED
4. 04Prepared SubgradeCOMPACTED EARTH

Fig. 1 — Typical crest and slope arrangement. HDPE thickness, geotextile GSM and protection arrangement finalised from site conditions.

For a lined reservoir, long-term performance depends more on installation quality than on any single line in the specification.

The approach therefore carries quality-control procedures through construction: subgrade inspection, panel placement, trial seams, extrusion and fusion welding, seam testing, repair of defects and final liner inspection.

Particular attention goes to anchoring trenches, pipe penetrations, inlet and outlet connections and changes in slope. These are the locations where liner continuity is won or lost, and where a reservoir that performs diverges from one that slowly disappoints. The objective is a completed geomembrane system that provides a reliable, continuous containment barrier across the whole reservoir.

The reservoir was planned as part of the plant's broader process-water management system, not as a standalone civil structure. It adds storage capacity and supports better management of process-water requirements across the operation.

The configuration can be integrated with existing pumping, inlet and outlet systems, allowing controlled filling, storage and withdrawal according to operational need — giving the plant flexibility in water management and more efficient use of the water resources available to it.

The documentation covers the reservoir layout, plan and sections, excavation and earthwork details, embankment geometry, slope details, HDPE geomembrane layout, anchoring arrangement, liner termination, inlet and outlet interfaces and the relevant construction details. Drawings were developed for clear site execution and for proper coordination between the civil earthwork and the geosynthetic lining — the interface where these projects most often go wrong, because two trades read two different sets of drawings.

1. 01Site Requirement
2. 02Feasibility
3. 03Reservoir Geometry
4. 04Earthwork & Subgrade
5. 05HDPE Containment
6. 06Anchoring & Interfaces
7. 07Quality-Controlled Install
8. 08Reliable Storage

Fig. 2 — Value engineering sequence, from site requirement to a reliable storage facility. Earthwork and geosynthetic design coordinated throughout — one continuous containment system, not two separate packages.

The project provided the client with an engineered process-water storage reservoir incorporating HDPE geomembrane containment. Properly designed earthwork combined with a low-permeability liner is an effective way to minimise seepage while creating a durable, maintainable storage facility.

It also demonstrates the value of geosynthetic technology in industrial water storage, particularly where reliable containment, efficient construction and controlled water management are the governing objectives.

This project combines earthwork engineering and geosynthetic technology to produce reliable industrial water-storage infrastructure: engineering planning, reservoir earthwork design, HDPE geomembrane lining and detailed construction documentation aimed at water containment, seepage reduction, durability and practical construction — specialist consultancy for industrial reservoirs, process-water storage facilities, lined ponds and geosynthetic containment systems across the beverage, FMCG and manufacturing sectors.

• 01

  Industrial reservoir and lined pond design

• 02

  Reservoir earthwork and subgrade engineering

• 03

  HDPE geomembrane lining systems

• 04

  Liner anchoring, termination and interface detailing

• 05

  Geosynthetic installation quality control

• 06

  Construction drawings and technical consultancy