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The direct cause for the dieback of mangrove trees is the lack of refreshment in the backwaters of Lac Bay. In a healthy mangrove system, channels provide fresh seawater to flow in and out towards the back of the mangroves. In this case, these channels are blocked, causing the back of the mangrove system to suffer from the highly saline and hypoxia environment that is now present.

During and after rain events, large amounts of sediments and topsoil are being transported by the surface run off into the shallow backwaters of Lac Bay. These sediments cause the already shallow back waters of Lac Bay to become even more shallow, increasing both temperature and evaporation. Furthermore, nutrient rich sediments enter the channels, where they increase mangrove growth. This growth can eventually block passages and channels.

The reason for the blockage of the mangrove channels is caused by terrestrial factors, in this case the ongoing unsustainable land use. Overgrazing by invasive herbivores in the northern watershed of Lac Bay has increased erosion due to the lack of soil cover (vegetation). Furthermore, the former agricultural areas are periodically stripped of vegetation and topsoil to ‘clean’ the land.

The most effective, short-term measurement to stop the sediment flows from reaching Lac Bay is the construction of dams. These dams stop the water and allow it to slowly infiltrate into the subterrane, thereby also retaining the sediments on the spot. A system of dams will be constructed between the easternmost area of Chaparal and the large existing dam of Bakuna. This line of dams will connect all current existing dams and furthermore repair or fill up potential gaps. This system is referred to as the Lac linie, originating from the Dutch term of defense line. The goal of the Lac linie is to effectively block the flow of sediments into Lac Bay from the North.