Performance assessment of existing canal-blocking in restoration management of peatland conservation

The aim of this research is to assess existing results of the canal-blocking peatland conservation due to the classification of 5 canal-blocking types on peatland conservation as the management of restoration in the peatland area of Block-C ex-PLG. The low water levels (>40 cm from the surface) during the dry season make dry peatlands susceptible to fires. The back wetting of peatland is the early effort in preventing the peatland fire, which can be carried out on a wide scale by exploiting the available canal network through the overall and integrated canal blocking in unity of peatland hydraulics. The canal blocking due to the five types of canal blocking classification, which is intended to back the discussion of peatland, can give the ecology and society economic impacts that include supporting the natural vegetation recovery, preparation of water supply along season on the peatland hydrologic unity, and to be preventing drought and also the fire that are often happened in the dry season. Land use is suggested based on customization: agriculture and plantation in designated areas, adaptive vegetation in limited plantation zones, and protected areas restored to serve as safeguarded vegetation zones.


Introduction
Tropical peatlands worldwide cover an area of 40 million ha, and half of this area is found in Indonesia, such as Sumatra, Kalimantan, Papua and Sulawesi.Peatlands have the ability to store a very large amount of water (90% of the volume), so peatlands can be expected to function as a hydrological buffer for the surrounding area.In 1993-1997, the condition of forests and peatlands in Indonesia, especially in Kalimantan, continued to degrade due to large-scale land clearing (PLG) without considering aspects of the peat hydrological area (KHG), causing drought problems in peatlands, which had implications for large fires every year that caused thick haze for months, which had an impact on economic, social and health costs.Despite previous canal construction for water resources system management, forest and peatland fires are still a problem.
The main principle for decreasing and preventing the fire and smog in the peatland is hydrology restoration action [1].It is based on the fact that as a result of too much drainage canal construction when the opening of one million ha area (PLG), mainly in the work area of block-C, has caused peatland damage which impacts the local economy at a time supporting the happening of global GRK emission.Without the peatland hydrology restoration, the intervention of the other peatland 1311 (2024) 012059 IOP Publishing doi:10.1088/1755-1315/1311/1/012059 2 management like tree planting and fire controlling are predicted to have less significant effect or difference [2], [3].
The failure to restore hydrology can cause the peatland management problem to be endless, and the fire damages the peatland hydrology unity ecosystem of the protected area [4], limited plantation area until plantation area and one of the impacts is the thick smog that causes the disturbance of healthy and economic mobility.The canal network in the work area of block-C ex PLG is wide enough and long not only to dry the available peatland.However, it also tends to become the origin of fire [5], which is not on purpose, as well as the fire as the reason for area cleaning activity.Therefore, canal closing is also hoped to limit the number of persons who enter the peatland area and decrease the risk of fire.
The above shows that the main and biggest challenge to avoid the repetition of peatland fire and smog is to keep the peatland from risk during the dry season [5], [6].Therefore, accurate and fast action in the prevention and management of disasters, remembering that canal blocking is useful in increasing the water level depth of an area [7] and works to maintain the decline speed of extreme water surface [8] during the dry season and fire-prone.Figure 1 presents the peatland spread map of peatland hydrology unity in Block-C Area.
The Block C peatland landscape is part of the former EMRP located in Pulang Pisau District, Central Kalimantan Province.This location is included in the peat hydrological unit #14, which is flanked by the Kahayan River to the east and the Sebangau River to the west.Block C covers the districts of Kahayan Kuala, Sebangau Kuala, Pandih Batu, Maliku, Kahayan Hilir and Jabiren raya, Pulang Pisau District, Central Kalimantan Province.The aim of this research is to carry out the assessment of existing results of peatland conservation that used canal-blocking due to the classification of 5 canal-blocking types on peatland conservation as the management of restoration in the peatland area of Block-C ex-PLG.

Review of Literature
The peatland management in the last period in the work area of Block-C ex PLG does not consider the natural characteristic of peatland that is prone and the impact of clean and drain work.Peatland includes a dynamic system.Peatland and its drainage cause the oxidation of peatland and decline soil through the compaction process, and peatland losses are the oxidation reason.The change in peatland topography is due to the oxidation process.The topography change affects the drainage condition and hydrology cycle, which increases the flooding potency [9].However, in Block-C-ex.PLG area is needed for the approach of integration, rapid management, and peatland rehabilitation that covers fire countermeasures, hydrology improvement, reforestation, and population development that make the increasing of consciousness and supporting to the intervention that is proposed, then produces a longterm society-profit.To reach accurate peatland management, stop the direction of outflow of peatland (more than 3 metres) and further channel peatland drainage (from 1 metre to 3 metres) [10].Drainage can cause the surface of groundwater to lower [8], and the impact is the peatland subsidence by the decay, shrinkage, and decomposition.The peatland decay has produced emissiongas of CO2 that miss out on the atmosphere that influences climate [11].The surface of the water is necessary to increase if it will be decreasing the CO2 emission and it expressed management work of Block-C, then it generally will have a limited impact for short-term groundwater depth.It is caused by the landscape, which is drastically changed.Therefore, more embankments can irrigate back only in narrow areas of the channel.
The influence on CO2 emission will also be limited in a short time.This is due to the water surface increasing effort in the channel closure [12].Even so, making embankments in a channel is needed to rehabilitate the long-term peatland.It is due to a base-level-out creation where the decay of peatland is not able to go on.In order for the embankment of a channel to be effective in this way, there must exist a strong embankment for decades, and it needs maintenance regularly.In most areas, the channel embankment cannot be maintained to make the channel edge remain wet.Therefore, it is needed the prevention and management of fire which the Tabat is developed to curb-channel.However, Tabat has to be developed to increase the surface of water as high as possible.The best is to develop the peak of Tabat high enough that it remains more than the water surface during the water flow.The maximum height for developing Tabat is a wide, flat lowland on at least one side.
Water pressure in the structure has to be minimized, so the water height difference among each Tabat must be < 0.5 metres.It has also to be remembered that the different peatland has different hydrology characteristic.The process of humification in the peat deposits, which is low, is possible the groundwater flow is bigger.
In the Block-C ex PLG on the thick peatland, further development has to be prevented, has to be carried out the channel closure and available drain, and the groundwater surface will increase.The analysis of hydrology that is carried out can be shown as follows [13], [14]: 1.Now, the edge of the channel is 1 metre or > under a level of peat dome.This is due to the mini topography of the dome.2. The closure of the channel is able to irrigate back wide peatland in a limited (short) time, which is necessary to be carried out to avoid the next damage.However, it is due to the horizontalhydraulic-conductivity that is limited.The channel closure can often irrigate the region in a short period by the area between 300-500 metres at the surrounding channel.However, it is urgent to prevent the fire from restoring the ecology.In shallow peatland (from 1 to 3 metres), there has to be limited drainage.However, if it happens, there has to be water control to make sure order water loss in the dry season and water surplus in the rainy season.

Method of Research
The research place is in the hydrology unity of peatland in the Block-C ex PLG, where it is located between two big rivers, the Kahayan River and Sebangau River, Pulang Pisau Regency-Centre Borneo Province.This peat hydrology unity is interesting enough because there is much area utilization that is carried out by the government through the program of agriculture area plantation and management of protected forests as well as private parties through the corporate plantation concession and local population parties by the society plantation.The research steps are as follows [15]: 1.To find primary data due to the parameters which have been carried out before in applied study as the main data; 2. To collect the secondary data, that is, a literature study that has been carried out for deepening analysis; 3. The analysis result will be carried out to make the conclusion that is related to the assessment of existing canal blocking performance on the management of peatland conservation-restoration.
Figure 2 presents the zone map of the canal blocking the Block-C area.

Results and Discussion
To implement the restoration management of peatland conservation based on the peat hydrologicalunity comprehensively, however, the parameters below are necessary to: 1.The peat management zone of scientific hydrology consists of a protection zone, a limited plantation zone, and a plantation zone.2. To determine a model of blocking type like area status technical and legality, local wisdom and social.3. The classification of blocking construction type consists of backfilling, compacted peat dam, semipermanent canal-blocking (made of wood), and permanent canal blocking (made of concrete) The available handling pattern is by carrying out the handling problem identification of peatland conservation and management of restoration regarding parameters on the management peat zone of scientific hydrology, influenced aspect to the model type of blocking and blocking construction.To determine the parameter of the management of restoration on the peatland conservation is presented in Figure 3.

Figure 3. Map of ex-PLG
The surface of the water is in accordance with the demand of groundwater level on the right and left side of the channel, so the development of canal blocking has to be given the direction for creating the difference in the highest water depth level between each blocking about ±40 cm.The ideal canal blocking is developed in accordance with the climate change conditions.If the climate changes from the dry season into the rainy season (two minutes before the rainy season), the canal blocking the dome centre of protected area peat (upstream) and then the network is expanded a little by little towards the dome edge or until the plantation area (downstream).To identify the correlation between placing a system of canal blocking based on the problem from the zone parameter of peat scientific hydrology management zone, the aspects that affect are the blocking type model and blocking construction model.
However, the illustration of existing condition on five types of blocking canal on the available handling pattern is as follow: 1. Backfilling canal blocking (Figure 4, 5, and 6) which the designation is in the condition as follow: a.The peat thickness of the protected area is more than 5 meters b.This channel type is not used for navigation by society c.The channel has the potential to be used as a wood logging channel.So, this area is dangerous due to the fire damage.d.If the channel is combined by semi-permanent blocking downstream and the construction is less than 25 meters, there is long-lasting construction resilience.e.This type is to have functioned as the channel closure blocking, in which the range of length is from 100 to 300 meters.
Overview of the water system in the area Kesatuan Hidrologis Gambut (KHG) with a controlled system   a.This canal blocking is located in the protection area.b.The channel type is still used by part of society as the navigation channel.c.There is a society plantation in a small area.d.If the canal blocking is combined with a semi-permanent type downstream, it has the resilience of long-lasting construction.It is constructed on a channel that is less than 25 meters, and the length is up to 50 meters.e.The thickness of peat is from 3 to 5 meters and is functioned as the controlled blocking.f.This type of canal blocking is used on the flowing current of the slow channel, and there is very minimal local material surrounding it, and there is a limited location point of activity.It is constructed on a channel that is less than 20 meters, and the diameter is between 0.1 and 0.15 meters.e.This type of canal blocking has functioned as water pressure reduction blocking, and this type is located in the adaptive area, where the concrete blocking is downstream.f.This type of canal blocking is used in a pretty heavy channel, and there is very minimal local material surrounding it.It is constructed on a channel that is more than 10 meters.The diameter of the wood is between 0.2 and 0.25 meters, and the length is between 4 and 6 meters.e.This kind of canal blocking functions as the lock blocking and is located downstream of the protection area, which uses the backfilling blocking upstream.f.This type of canal blocking is used in a pretty heavy channel, and there is very minimal local material surrounding it.

Conclusions
Based on the assessment result of existing performance for five types of canal blocking on the available handling pattern, it can be concluded that the canal blocking performance has been well functioned, which can give the impact of ecology and society economy that include: 1) to support the vegetation recovery naturally; 2) water supply along season on the peat hydrology unity; 3) to prevent drought and fire on the dry season.Therefore, the land use can be customized the designation as follows: the plantation area for agriculture and plantation development; the limited plantation area is utilized for adaptive vegetation in accordance with area conditions; and the protected area is restored function as the vegetation area that is protected.

Figure 2 .
Figure 2. Zone map of canal blocking in the Block-C area Source: Ministry of General Work and Housing (2017)

Figure 6 .
Figure 6.Condition of backfilling canal blocking area that has been functioned 2. Compacted peat dam canal blocking (Figure 7, 8, 9) which the designation is in the condition as follows: a.This canal blocking is located in the protection area.b.The channel type is still used by part of society as the navigation channel.c.There is a society plantation in a small area.d.If the canal blocking is combined with a semi-permanent type downstream, it has the resilience of long-lasting construction.It is constructed on a channel that is less than 25 meters, and the length is up to 50 meters.e.The thickness of peat is from 3 to 5 meters and is functioned as the controlled blocking.f.This type of canal blocking is used on the flowing current of the slow channel, and there is very minimal local material surrounding it, and there is a limited location point of activity.

Figure 13 . 11 Figure 14 .Figure 15 .Figure 16 .
Figure 13.semi-permanent canal blocking by using local wood of coconut trees with a channel width of 25 m