Breaking the Cycle of Dredging: A Smart Sedimentation Solution in Mahakam River Delta

When sediment refuses to stay where it belongs, industries pay the price. Around the world, rivers and estuaries deliver not only water but also sand, silt, and mud, materials that slowly but relentlessly clog and disrupt critical infrastructures. Dredging can buy time, but it never wins the war. Each scoop of removed sediment material is eventually replaced by the next tide. This was the reality faced by an oil and gas company at the Mahakam River Delta in East Kalimantan, Indonesia.

At the water intake in Mahakam, sediment piled up time after time, threatening the reliability of critical water supplies. Each dredging campaign came with high costs, operational delays, and unavoidable environmental disturbances, yet the river kept returning the sediments as if nothing had been done. The Company needed a different strategy, one that would look beyond short-term fixes and address the root cause of the problem. To break this cycle, The Company partnered with PT Pageo Utama and PT Bhumi Warih Geohydromatics to search for a long-term, science-based solution. The objective was clear: identify the key drivers of sedimentation and develop a practical engineering design that could reduce the frequency of dredging while keeping the water intake safe and operational.

How did we do it?

The team began with a deep dive into the Mahakam’s natural rhythms. A detailed field survey gathered measurements of currents, tides, bathymetry, and sediment characteristics, capturing the river’s hidden mechanics. Historical data on rainfall were reviewed to understand seasonal patterns, while wave climate analyses revealed how offshore forces shaped local hydrodynamics. Even the configuration of piles was scrutinized to assess whether man-made obstacles were steering sediment toward the intake. Examples of the deliverables, analyses, and literature review are presented in Figure 1.

Figure 1

Figure 1. 1) Current Rose; 2) Current Speed Profile; 3) Sediment Particle Distribution Graph; 4) Average Monthly Rainfall.

Armed with this information, the team developed a high-resolution numerical model (up to 1 m) to simulate hydrodynamics and sediment transport, enabling precise representation of the structure piles within the model. This virtual Mahakam allowed us to test multiple strategies without moving a single grain of sand in the real river. Model scenarios were carefully developed to provide targeted solutions to this challenge. The best solution identified was to relocate the water intake to a new structure. Modeling showed that moving the intake to this location would dramatically reduce sediment accumulation up to four times less than at the existing site as illustrated in Figure 2. In the original intake area, sedimentation could reach 321 m³ per month, whereas the same-sized area at the new structure is projected to accumulate only 78 m³ per month, greatly reducing the need for dredging. Beyond the numbers, relocation offers long-term stability, lower operational risk, and substantial savings in maintenance costs.

Figure 2 Figure 2. Cumulative erosion/sedimentation of scenarios 1.) Existing Condition; 2) Suggested new structure for intake relocation.

The impact of this recommendation reaches far beyond economics. A more stable intake system means reliable operations for The Company, while reduced dredging translates to fewer disruptions of the fragile Mahakam Delta ecosystem. Less machinery in the river means less noise, fewer emissions, and a smaller ecological footprint, proving that smart engineering can benefit both industry and environment.

Behind this achievement was a strong collaboration between PT Bhumi Warih Geohydromatics and PT Pageo Utama. Together, we combined Pageo’s precise measurements with our advanced numerical modeling and engineering analysis to transform a complex sedimentation challenge into a clear, actionable plan. By integrating field expertise with high-resolution modeling, we turned raw data into a practical solution. Showing how data-driven science can outsmart natural forces and break the cycle of costly dredging.

If your operation is facing sedimentation problems, whether it’s blocked intakes, reduced navigational depth, or unexpected build-up, why keep relying on costly short-term fixes? With the right data and engineering, we can help you predict, prevent, and manage sediment movement before it disrupts your operations. Let’s work with nature, not against it. Contact us at bw@bwgeohydromatics.com to start building a smarter, long-term solution today.