scholarly journals The Characteristic of Groundwater Table and Subsidence of Degraded Peatland in Ex ICCTF Plot Central Kalimantan

Author(s):  
Muhammad Anang Firmansyah ◽  
Wahyu Adi Nugroho

Degraded peatlands typically have been cultivated by communities for agriculture. Ex ICCTF plot in Jabiren is considered as a degraded peatland since the area has been cultivated and drained for smallholder plantation. This study aimed to characterise the groundwater level and peat subsidence periodically over seven months of observation. It has been found that the groundwater level fluctuated from 50 cm to 150 cm below the peat surface, implying the deterioration of peat ecosystem. Based on the transect observation, the groundwater table seems to form a dome shape with the deeper level existed adjacent to the canal. The average peat subsidence was around 27 to 39 cm in cumulative since the subsidence stick installation. However, in the range of ten-month of observation, the peat subsidence was around 8.5 cm. The subsidence was higher on the location adjacent to the canal (25 m) compared to the farther one (100 m). The subsidence also fluctuated, notably in the wet season, indicating the influence of rain event to peat subsidence.  Rewetting peatland was likely to result in reducing peat subsidence suggesting the importance of water management in peatland to recover degraded peatland.

2020 ◽  
Vol 12 (21) ◽  
pp. 8932
Author(s):  
Kusum Pandey ◽  
Shiv Kumar ◽  
Anurag Malik ◽  
Alban Kuriqi

Accurate information about groundwater level prediction is crucial for effective planning and management of groundwater resources. In the present study, the Artificial Neural Network (ANN), optimized with a Genetic Algorithm (GA-ANN), was employed for seasonal groundwater table depth (GWTD) prediction in the area between the Ganga and Hindon rivers located in Uttar Pradesh State, India. A total of 18 models for both seasons (nine for the pre-monsoon and nine for the post-monsoon) have been formulated by using groundwater recharge (GWR), groundwater discharge (GWD), and previous groundwater level data from a 21-year period (1994–2014). The hybrid GA-ANN models’ predictive ability was evaluated against the traditional GA models based on statistical indicators and visual inspection. The results appraisal indicates that the hybrid GA-ANN models outperformed the GA models for predicting the seasonal GWTD in the study region. Overall, the hybrid GA-ANN-8 model with an 8-9-1 structure (i.e., 8: inputs, 9: neurons in the hidden layer, and 1: output) was nominated optimal for predicting the GWTD during pre- and post-monsoon seasons. Additionally, it was noted that the maximum number of input variables in the hybrid GA-ANN approach improved the prediction accuracy. In conclusion, the proposed hybrid GA-ANN model’s findings could be readily transferable or implemented in other parts of the world, specifically those with similar geology and hydrogeology conditions for sustainable planning and groundwater resources management.


2021 ◽  
Author(s):  
Shih-Kai Chen ◽  
Yuan-Jie Lin ◽  
Yuan-Yu Lee

<p>The Taipei Basin, Taiwan has been densely populated and highly economically developed in recent decades. Global climate change has led to frequently flooding and drought events in recent years, formulating suitable measures to mitigate climatic disaster has become a crucial issue in this city. The sponge city concept is one of the most important options for disaster mitigation in highly urbanization areas. However, the city is also potentially threatened by soil liquefaction due to its sedimentary geology and increasing groundwater level. High groundwater level might be a key limiting factor in the promotion of sponge city. The aim of this study was to understand the relationship between rainfall and groundwater level and the impacts of cumulative rainfall, depth to groundwater table, and impervious pavement ratio on the rainfall/groundwater level response in study area. The cross-correlation function (CCF) was applied to analyze the correlation between rainfall and groundwater level data obtained from 20 observed wells and nearby rainfall gages during dry and wet seasons from 2012 to 2017. The significance groundwater recharge response can be found in 61% and 37% of the observation wells during the wet and dry seasons, respectively. Compared with the factors such as cumulative rainfall, and depth to groundwater table, the ratio of surface impervious pavement is the primary affecting factor behind the correlation between rainfall and groundwater level response. The analysis results also show the areas with shallow groundwater level, high imperious pavement ratio, and the groundwater level with no significant response to rainfall, are almost overlapped with the middle and high level liquefaction potential areas in this city. Measures such as the application of the sponge city concept to increase infiltration should be carefully reevaluated in this city. The research results can provide a reference for the future development of urban water resources management and disaster mitigation strategies under the challenge of globe climate change.</p>


2018 ◽  
Vol 55 (1) ◽  
pp. 45-54
Author(s):  
Manish Shrestha ◽  
Naresh Kazi Tamrakar

Groundwater is the water which is present in pore spaces and in the fractures of the geological materials beneath earth surface. Water is incompressible substance and presence of small amount of water in geological material modifies the behavior of geological material under stresses. Determination of engineering behavior of the geological material is almost impossible skipping the role of water. The objective of this study was to map and evaluate shallow groundwater level of the northern Kathmandu Valley covering main rivers such as the Bagmati River, Bishnumati River, Dhobi Khola and the Manahara Khola. These rivers flow from the North to the South across the sand rich sediment zone. Static groundwater levels of 239 wells were measured from different locations of the study area in April/March 2017 (Dry Season) and in August 2017 (Wet Season). Shallow groundwater level was measured from soil surface to water level using well water depth logger (Qin and Li, 1998). The result showed that groundwater level ranged from 0.6 m to 12.5 m in dry season and 0.1 m to 13 m in wet season. The groundwater level increased by average of 34.68% (n = 235) as compared to that in dry season. Increase in the groundwater level suggests recharge of groundwater in wet season of the study area. The flow pattern of groundwater levels from the study shows flow of shallow groundwater towards the major rivers of that particular river watershed. As a consequence, seepage flow and piping erosion is likely along the riverbank slopes. Increase in recharge of groundwater during wet season exhibits that the northern region of the Kathmandu Valley is potential for groundwater recharge and can be used to manage water for the dry period.


2020 ◽  
Vol 10 (24) ◽  
pp. 8882
Author(s):  
Jing-Ying Huang ◽  
Dong-Sin Shih

Although the annual rainfall in Taiwan is high, water shortages still occasionally occur owing to its nonuniform temporal and spatial distribution. At these times, the groundwater is considered an acceptable alternative water source. Groundwater is of particular value because it is considered a clean and reliable source of fresh water. To prevent water scarcity, this study utilized seasonal forecasting by incorporating hydrological models to evaluate the seasonal groundwater level. The seasonal prospective issued by the Central Weather Bureau of Taiwan (CWB) was combined with weather generator data to construct seasonal weather forecasts as the input for hydrological models. A rainfall-runoff model, HEC-HMS, and a coupled groundwater and surface water model, WASH123D, were applied to simulate the seasonal groundwater levels. The Fengshan Creek basin in northern Taiwan was selected as a study site to test the proposed approach. The simulations demonstrated stability and feasibility, and the results agreed with the observed groundwater table. The calibrations indicated that the average errors of river stage were 0.850 for R2, 0.279 for root-mean-square error (RMSE), and 0.824 for efficiency coefficient (CE). The simulation also revealed that the simulated groundwater table corresponded with observed hydrographs very well (R2 of 0.607, RMSE of 0.282 m, and CE of 0.621). The parameters were verified in this study, and they were deemed practical and adequate for subsequent seasonal assessment. The seasonal forecast of 2018 at Guanxi station indicated that the 25th and 75th percentiles of simulated annual rainfall were within 1921–3285 mm and the actual annual rainfall was 2031 mm. Its seasonal rainfall outlook was around 30% accurate for forecasts of three consecutive months in 2018. Similarly, at Xinpu station, its seasonal rainfall outlook was about 40% accurate, and the amount of annual rainfall (1295 mm) was within the range of the 25th and 75th percentiles (1193–1852 mm). This revealed that the actual annual precipitations at both Guanxi and Xinpu station corresponded with the range of 25th and 75th percentiles of simulated rainfall, even if the accurate rate for the 3 month seasonal forecast had some error. The subsequent groundwater simulations were overestimated because the amount of actual rainfall was far lower than the average of the historical record in some dry season months. However, the amount of rainfall returned to normal values during the wet seasons, where the seasonal forecast and observation results were similar.


2015 ◽  
Vol 27 (1) ◽  
pp. 118-129 ◽  
Author(s):  
Ludmilla Cavalcanti Antunes Lucena ◽  
Thaís Xavier de Melo ◽  
Elvio Sergio Figueredo Medeiros

Aim:The objective of the present work is to present a list of species of zooplankton (Rotifera, Cladocera and Copepoda) from the Parnaíba River. Additionally, we provide comments on their distribution along the river, and between dry and wet seasons.MethodsZooplankton was collected with a plankton net (60 µm mesh) and concentrated into a volume of 80 mL for further analysis, during the dry (October 2010) and wet (April 2011) seasons. Sampling was restricted to the marginal areas at depths between 80 and 150 cm.ResultsA total of 132 species was recorded among the three zooplankton groups studied. During the dry season a total of 82 species was registered and 102 species was registered for the wet season. Rotifera contributed with 66.7% of the species, followed by Cladocera (26.5%) and Copepoda (6.8%).ConclusionsThe richness of species observed was high compared to other large rivers in Brazil. In the context of current policies for water management and river diversions in northeastern Brazil, the present study highlights the importance of this river system for biodiversity conservation.


2013 ◽  
Vol 14 (3) ◽  
pp. 390-397 ◽  
Author(s):  
Sadhana Shrestha ◽  
Takashi Nakamura ◽  
Rabin Malla ◽  
Kei Nishida

To develop effective groundwater pollution control strategies for the Kathmandu Valley, Nepal, seasonal variations in microbial quality and their underlying mechanisms must be understood. However, to date, there are no studies that address these topics. In this study, groundwater samples from dug wells were collected during the dry and wet seasons from 2009 to 2012, and Escherichia coli (E. coli) and total coliforms were analysed. Three wells were monitored each month for a year. Microbial concentrations in shallow groundwater were significantly higher during the wet season than during the dry season. Analyses of rainfall and E. coli concentrations in different seasons indicated that a high level of faecal material infiltration during the rainy season may have caused the seasonal variations in microbial quality. A moderate to strong relationship between E. coli concentrations and groundwater level suggested that the rise in groundwater levels during the wet season may be another reason for this variation. This long time-scale survey detected a significant decline in the microbial quality of shallow groundwater during the wet season as compared with the dry season. We propose that the infiltration of contaminants and change in groundwater level are the two probable mechanisms for the observed seasonal differences.


2018 ◽  
Vol 40 (2) ◽  
pp. 66
Author(s):  
Ignasius Dwi Atmana Sutapa ◽  
Eni Maftuah ◽  
Astried Sunaryani ◽  
Hidayat Pawitan

Peat swamp forest is a unique and fragile ecosystem, with specific flora and fauna that play important roles in maintaining healthy natural conditions with high economic values. This habitat also has important role for equilibrium and maintenance of living environment such as water reservoir, carbon storage, climate change, and biodiversity. Utilization of peatland for agriculture, plantations, and other activities often lead not only to controversy, but also cause land and ecosystem degradation, including water resources availability. The objective of this research was to study comprehensive ecohydrology aspects in ex-mega rice project in Central Kalimantan in order to support sustainable agricultural practices and water resources management in peatland areas. The results of the study showed that the sustainability of agricultural systems in peatland was strongly influenced by ecological aspect. This aspect can be carried out from the condition of water management system, water color condition, and possible incidence of fires. The level of suitability for crops plantation was low (S3), with the limiting factors of pH, nutrient availability, and the risk of inundation. In this case, water gates should be installed to improve water management system. Water quality in this area was typical of peat water and do not meet the requirement for daily use for the local people.


Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 856
Author(s):  
Yosefin Ari Silvianingsih ◽  
Kurniatun Hairiah ◽  
Didik Suprayogo ◽  
Meine van Noordwijk

Increased agricultural use of tropical peatlands has negative environmental effects. Drainage leads to landscape-wide degradation and fire risks. Livelihood strategies in peatland ecosystems have traditionally focused on transitions from riverbanks to peatland forests. Riparian ‘Kaleka’ agroforests with more than 100 years of history persist in the peatlands of Central Kalimantan (Indonesia), where large-scale open-field agricultural projects have dramatically failed. Our field study in a Dayak Ngaju village on the Kahayan river in the Pulang Pisau district involved characterizing land uses, surveying vegetation, measuring soil characteristics, and monitoring groundwater during a period of 16 months. We focused on how local practices and farmer knowledge compare with standard soil fertility (physical, chemical, biological) measurements to make meaningful assessments of risks and opportunities for sustainable land use within site-specific constraints. The Kaleka agroforests around a former settlement and sacred historical meaning are species-rich agroforests dominated by local fruit trees and rubber close to the riverbank. They function well with high wet-season groundwater tables (up to −15 cm) compatible with peatland restoration targets. Existing soil quality indices rate the soils, with low soil pH and high Alexch, as having low suitability for most annual crops, but active tree regeneration in Kaleka shows sustainability.


2021 ◽  
Vol 53 (2) ◽  
pp. 210205
Author(s):  
Yadi Suryadi ◽  
Indratmo Soekarno ◽  
Ivan Aliyatul Humam

The height of canal blocking has a significant influence on re-wetting peatland, depending on the canal’s distance. An effective canal in good condition has to raise the groundwater table to -0.4 m below ground level according to the Indonesian Ministry of Environment and Forestry (MENLHK). The effectiveness of different canal blockings was modeled by Freewat software with variation of canal distance (200 m, 250 m, 300 m, 350 m, and 400 m) and blocking height (0.2 m, 0.3 m, 0.4 m, 0.5 m, 0.6 m). This simulation was carried out using recharge and evapotranspiration data covering 20 years. The input of the conductivity value was done using 50 m/day according to the calibration. From the modeling, 0.6 m high canal blockings give a satisfactory result at every canal distance. The study took place during the annual dry season, when recharge was almost zero and average evapotranspiration was 6 mm/day. Adjusting the canal blocking to a maximum of 0.6 m and the canal distance to 400 m, the groundwater table slowly rose 0.38 m and it took 30 days to reach full-re-wetting capacity. This study revealed that the effectiveness of canal blocking is directly related to evapotranspiration and recharge, which has a positive correlation with the groundwater rise and the re-wetting period.


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