3.9.3 Water Reservoir Construction Design
In the dry season that drastically decreased the GWL, WSL-MTI developed natural
water reservoirs at the top of the peat dome to distribute water to the whole area or
the areas where water is lacking. The water reservoir is often in the same location as
the conservation area in concessions with high biodiversity and genetic resources.
Although the water reservoir is not a pond, it accumulates a significant, yet unseen,
amount of water underground. To maximize the volume of water storage, the GWL
of the water reservoir area has always been kept at a level of approximately zero cm,
which is the highest level in the concession. The water level has never affected the
remaining peat forests.
In general, the water level of the water reservoir drops to between 40 and 50 cm
from the ground surface in the dry season. However, in 2019, the GWL of the water
reservoir dropped to an average of 71.5 cm during the dry season because of a
slightly intense drought linked to the El Niño effect. Moreover, the GWL of the
plantation area was kept at above the standard of 40 cm. It should be noted that the
water reservoir supplies water to the whole area. However, it is presumed that the
average GWL of 71.5 cm in the water reservoir during the dry season in 2019 is still
within the normal range in comparison to that in the natural forest without a water
management, which often drops to more than 100 cm from the ground surface.
As described above, the arrangement of the water reservoir is an extremely
important part as the “Stock-based water management.”
3.9.4 Hydrobuffer Zone Construction Design
To maintain the high GWL in the conservation area, WSL-MTI allocated a
hydrobuffer zone of approximately 400 m in width. The hydrobuffer was located
between the water reservoir (conservation area) and the plantation area. The GWL of
the hydrobuffer zone was set to 0–20 cm. The extremely high GWL enabled the
neighboring water reservoir to maintain a high GWL and to stabilize the saturated
conditions. Moreover, hydrobuffer played a vital role in the negative impacts of
planting activities on the conservation area (Fig. 3.16).
3.9.5 Infrastructure Construction
After the development of detailed water management zoning, artificial infrastructure
will be needed to properly manage each zone. The basic objective is to control the
one-way flow of water from one zone to the other. Conversely, the construction of
much of the infrastructure will be extremely costly. Therefore, a good management
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In the dry season that drastically decreased the GWL, WSL-MTI developed natural
water reservoirs at the top of the peat dome to distribute water to the whole area or
the areas where water is lacking. The water reservoir is often in the same location as
the conservation area in concessions with high biodiversity and genetic resources.
Although the water reservoir is not a pond, it accumulates a significant, yet unseen,
amount of water underground. To maximize the volume of water storage, the GWL
of the water reservoir area has always been kept at a level of approximately zero cm,
which is the highest level in the concession. The water level has never affected the
remaining peat forests.
In general, the water level of the water reservoir drops to between 40 and 50 cm
from the ground surface in the dry season. However, in 2019, the GWL of the water
reservoir dropped to an average of 71.5 cm during the dry season because of a
slightly intense drought linked to the El Niño effect. Moreover, the GWL of the
plantation area was kept at above the standard of 40 cm. It should be noted that the
water reservoir supplies water to the whole area. However, it is presumed that the
average GWL of 71.5 cm in the water reservoir during the dry season in 2019 is still
within the normal range in comparison to that in the natural forest without a water
management, which often drops to more than 100 cm from the ground surface.
As described above, the arrangement of the water reservoir is an extremely
important part as the “Stock-based water management.”
3.9.4 Hydrobuffer Zone Construction Design
To maintain the high GWL in the conservation area, WSL-MTI allocated a
hydrobuffer zone of approximately 400 m in width. The hydrobuffer was located
between the water reservoir (conservation area) and the plantation area. The GWL of
the hydrobuffer zone was set to 0–20 cm. The extremely high GWL enabled the
neighboring water reservoir to maintain a high GWL and to stabilize the saturated
conditions. Moreover, hydrobuffer played a vital role in the negative impacts of
planting activities on the conservation area (Fig. 3.16).
3.9.5 Infrastructure Construction
After the development of detailed water management zoning, artificial infrastructure
will be needed to properly manage each zone. The basic objective is to control the
one-way flow of water from one zone to the other. Conversely, the construction of
much of the infrastructure will be extremely costly. Therefore, a good management
112
T. Kato et al.