Decrease In Groundwater Table Research Articles

Dynamic of groundwater table, peat subsidence and carbon emission impacted from deforestation in tropical peatland, Riau, Indonesia

Drainage canals have triggered peat subsidence and lowered groundwater table, enabling wildfires and peat degradation in Riau, Indonesia. This study examines the changes on groundwater table, peat subsidence rate, and carbon emission in response to deforestation and land cover changes. We established 31 study sites in some land cover types (i.e., oil palm plantation, acacia regrowth and shrub), with 124 monitoring shallow wells and 31 subsidence poles that were setup and have been monitored for 18 months. Groundwater table of all plots averaged -55 cm in Dosan Village, higher than that in Dayun Village (-66 cm). In accordance, peat had subsided in faster rate (8.4 cm year−1) in Dayun Village than that in Dosan (3.3 cm year−1). This average annual groundwater table has resulted in carbon emissions from peat decomposition up to 66 t CO2eq ha−1 year−1. On the other hand, canal discharge of these sites ranged from 2 to 73 dm3 s−1, averaging 26 dm3 s−1. These results evidence that land uses converted from peat forest, and the dimension of canal control the decrease in groundwater table, the pace of peat subsidence, and rate of carbon emissions in tropical peatlands.

Study on Pervious Concrete by Partial Replacement of Silica Fume and GGBS with Cement and Addition of Glass Fibers

Pervious Concrete for the pavements proves to be an effective and along- term solution for the universal problem of abnormal decrease of ground water table. Pervious Concrete has a unique mix design and giving special properties to the concrete which makes the concrete porous , allowing water from precipitation and other sources to pass directly through , there by reducing run off volume and increasing ground water table. Inorder to reduce the damage being caused to the environment by the use of cement , inpervious concrete , cement is replaced with pozzolanic materials such as GGBS , silica fume sand to increase strength and durability , glass fibers in stipulated ratio are added to the concrete mixture. In this study ,the mix designs such as M30 and PC30 are considered . The fine aggregate is replaced with coarseaggregate by different ratios like 0% , 5% , 10% ,15%. by adding different pozzolanic matrals like GGBS, silicafume with glassfibers. To find the effectiveness of the use of pozzolancic and glassfibes, compressive strength conducted. The following Conclusions can be summarized by analyzing tests performed on PC specimens. A significant reduction of workability. And A progressive addition in compressive strength by increasing the percentage of fine aggregates and pozzolanic materials in mix. The conclusion of fine aggregate content in the specimen increases the density and increase the pozzolanic materials addition. And addition of silica fume and GGBS in the mixtures improve strength , compressive strength increases even after adding pozzolanic materials. Due to increase of fine aggregate content. For all replacement levels of PC with other mixes goes on decreasing in strength when compared with parent grade ofM30. While comparing with PC with Pozzolanic materials, For 7 days there is a drastic change for same replacement, and for 28 days itshowssimilar trend for 25% pozzolanic concrete and goes on decreasing for strength for compressive strength. For all replacement levels of PC with pozzolanic goes on decreasing in strength when compared with parent grade of M30. Compressive strength slightly increased by adding glass fibers to the allmixes.

Quantitative and qualitative analysis of groundwater affected by land use change

Compared to surface water, groundwater resources are the primary source of water supply in arid and semi-arid regions of Iran, hence the importance of the management of these resources . In this regard, we assessed the effects of landuse changes on the qualitative and quantitative status of groundwater resources in Eshtehard region, Iran. Through processing and analyzing the satellite images, the region was divided into six different land uses, namely agricultural lands, Haloxylon planted area, bareland, saline lands, rangelands, and urban areas; the maps pertaining to these land uses were then prepared. The ground water table fluctuation was assessed via the quantitative data of wells in the study area during 2000-2014. IDW interpolation method was employed to study the spatial variations of parameters, such as EC, Na, SAR, and TDS; afterwards, the maps related to the qualitative and quantitative changes in groundwater were prepared. The results showed that the rangelands, bare lands, and urban areas increased, and the agricultural lands decreased during the studied period. There was more reduction in groundwater table whereas water quality dropped. Generally, water quality was reduced from west to east, and there was more decrease in groundwater table from south to north. It could be deduced that human and natural factors, particularly over exploitation of groundwater, were the main reasons for these changes.

A Sustainable Study on Permeable Concrete using Bagasse Ash and Rice Husk Ash as a Partial Replacement of Cement

Permeable concrete is a special concrete which consists of cement, coarse aggregate and water. Due to rapid growth of globalization and urbanization, the construction of concrete roads increasing day by day which leads to decrease in percolation of storm water, surface runoff occurring to the decrease in ground water table. In previous concrete, single sized aggregate is used to maintain the void ratio in the concrete. The cement paste is bonded with aggregate with a void ratio of 20%. In this investigation, concrete of M20 grade with water cement ratio of 0.38 is used. The properties of concrete were increased by using Rice husk ash and Bagasse ash in changed percentages (10%, 20%, 30%) by weight of cement and with the combination of rice husk ash and bagasse ash 10% (5%RA + 5%BA), 20%(10%RA+10%BA), 30%(15%RA+15%BA) are used. The compressive strength of cubes, split tensile of cylinders are casted, tested after 7 days and 28 days. After testing, the optimum percentages of replacement of admixtures are found in the Permeable concrete. Therefore the strength and durability properties of permeable concrete with the addition of bagasse ash and rice husk ash with partial replacement of cement are compared with conventional concrete.

An Experimental Development on Pervious Concrete by Partial Replacement of Flyash, GGBS, Silica Fumes with cement by adding Glass Fiber

Pervious Concrete for the pavements proves to be an effective and a long-term solution for the universal problem of abnormal decrease of ground water table. Pervious Concrete has a unique mix design and giving special properties to the concrete which makes the concrete porous, allowing water from precipitation and other sources to pass directly through , thereby reducing run off volume and increasing ground water table. In order to reduce the damage being caused to the environment by the use of cement , in pervious concrete , cement is replaced with pozzolanic materials such as flyash , GGBS , silica fume sand to increase strength and durability , glass fibers in stipulated ratio are added to the concrete mixture. In this study, the mix designs such as M30 and PC30 are considered. The fine aggregate is replaced with coarse aggregate by different ratios like 0% , 5% , 10% ,15%. by adding different pozzolanic materials like flyash, GGBS, silica fumes with glass fibers. To find the effectiveness of the use of pozzolancic and glass fibers, compressive strength and split tensile strength are conducted.

DETERMINATION OF HABITAT 6270*_3 PERMITTED DRAINAGE RATE

Amelioration has dramatically altered the distribution of semi-natural grasslands in Latvia and as a result of the drainage, and the ocurrance of humid grassland habitats has decreased sharply. The aim of the paper was to identify drainage rate for habitat 6270*_3 ecohydrological requirements which is necessary for its successful management and long-term existence. The work looked at 15 equally managed (extensively grazed and/or mowed) perennial, natural grasslands at different levels of drainage resulting in various quality states. To reveal the most habitat-preserving drainage rate, for each site of the habitat 6270*_3 a decrease of groundwater table was identified. As a result a rate that meets ecohydrological requiremets is procured.

Hydrochemistry, water quality and land use signatures in an ephemeral tidal river: implications in water management in the southwestern coastal region of Bangladesh

Despite its complexity and importance in managing water resources in populous deltas, especially in tidal areas, literatures on tidal rivers and their land use linkage in connection to water quality and pollution are rare. Such information is of prior need for Integrated Water Resource Management in water scarce and climate change vulnerable regions, such as the southwestern coast of Bangladesh. Using water quality indices and multivariate analysis, we present here the land use signatures of a dying tidal river due to anthropogenic perturbation. Correlation matrix, hierarchical cluster analysis, factor analysis, and bio-geo-chemical fingerprints were used to quantify the hydro-chemical and anthropogenic processes and identify factors influencing the ionic concentrations. The results show remarkable spatial and temporal variations (p < 0.05) in water quality parameters. The lowest solute concentrations are observed at the mid reach of the stream where the agricultural and urban wastewater mix. Agricultural sites show higher concentration of DO, Na+ and K+ reflecting the effects of tidal spill-over and shrimp wastewater effluents nearby. Higher level of Salinity, EC, Cl−, HCO3−, NO3−, PO43− and TSS characterize the urban sites indicating a signature of land use dominated by direct discharge of household organic waste into the waters. The spatial variation in overall water quality suggests a periodic enhancement of quality especially for irrigation and non-drinking purposes during monsoon and post-monsoon, indicating significant influence of amount of rainfall in the basin. We recommend that, given the recent trend of increasing precipitation and ground water table decrease, such dying tidal river basins may serve as excellent surface water reservoir to supplement quality water supply to the region.

石羊河流域地下水系统脆弱性影响机理研究

为满足社会经济迅速的发展及日益增长的人口用水需求，人们对地下水进行了过度及不合理开发利用，从而引起一系列地下水的水环境问题，如，地下水位下降、水质恶化、水量减少等。特别是在干旱半干旱地区，水资源的污染加剧了水资源的紧缺状况，供需矛盾更加尖锐。本文以西北内陆河典型流域石羊河流域为例，从气温、蒸发量、降水量、径流量、水文地质构造等自然因素、土地资源及水资源的不合理开发利用等人为因素以及生态环境因素三个层面揭示了地下水系统脆弱性机理。分析结果表明：石羊河流域地下水系统的脆弱性是自然因素、人为因素和生态环境因素共同作用的结果。其中，在人类活动影响下，地下水和生态环境互为因果的恶性循环关系在使生态环境恶化的同时，也在水质和水量方面加剧了地下水系统功能的衰退。本文研究可为干旱区地下水资源保护提供理论指导意义。 With social and economic development and increasing demand of water, over exploitation of groundwater has caused a lot of groundwater environment problems, such as, worse water quality, decrease of groundwater table and water quantity. For the arid and semi-arid area, water resources pollution has made the water shortage more severe and the unbalance in water supply and demand sharper. Taking a typical watershed, Shiyang River watershed as an example, this paper analyzed the groundwater conno-tation and revealed the vulnerable mechanism from the natural, human and environmental factors. Analysis showed that groundwater vulnerability in Shiyang River Basin was impacted by the overall in-fluence of natural factors, human activities and environment. Under the influences of human activity, groundwater and ecology environment interacted with each other, which degraded the ecological system and sharpened the degradation of groundwater from quality and quantity. This research will have im-portant theoretical and practical guiding meanings.

The rivers of Africa: witness of climate change and human impact on the environment

AbstractIn this paper, we study the impact of climate change on river regimes in several parts of Africa, and we look at the most probable causes of these changes either climatically or anthropogenically driven. We study time series of updated monthly and annual runoff of rivers of North Africa, West Africa (Sahelian and humid tropical regions) and Central Africa, including the largest river basins: Niger and Volta rivers in West Africa, and Congo and Ogooue rivers in Central Africa. The recent years are studied in the perspective of multi‐decadal variability. In West Africa and in a part of Central Africa, the climate has changed since 1970, and rainfall has not returned to previous annual amounts, except in Equatorial Africa. The consequences of the long‐lasting drought are, depending on the area concerned, the modification of seasonal regimes (Equatorial area), the groundwater table decrease (Tropical humid area) and the land cover degradation (Sahelian area). The increasing number of dams and of agricultural areas also plays a major role on the modification of river regimes. The population increase will continue to impact on the environment: land cover change, deforestation, agriculture and increasing number of dams will be associated with a reduction of water and sediment discharges to the sea, and major impacts on downstream ecosystems and coastal areas. It seems necessary to share with stakeholders a comprehensive approach of the water cycle from the basin to the sea, to prevent long‐lasting damages to ecosystems and infrastructures. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Methane emission from peat-muck soil in the Biebrza River valley in relation to ground water level and fertilisation / Emisja metanu z gleby torfowo-murszowej w dolinie Biebrzy w zależności od poziomu wody gruntowej i nawożenia

Abstract The paper presents results of a two-year study on methane emission carried out in lysimetric station situated on Kuwasy peatland in the Biebrza River valley. The aim of this study was to estimate the amount of methane emission from peat-muck soil in relation to ground water level and fertilisation. Methane emission was determined with the chamber method using photo-acoustic probe. Methane emission significantly depended on the ground water level. The largest CH4 emission was found at full saturation of soil with water. With the decrease of ground water table the emission of methane decreased. Mineral fertilisation increased CH4 emission. At ground water table depth of 50 cm, CH4 emission from fertilised variant was by 42.3% bigger than from non- -fertilised variant. Peat-muck soils overgrown by meadows in the Biebrza River valley were found to be an important source of methane emission. In the vegetation period at ground water table depths of 0, 25, 50 and 75 cm methane emission was 502, 361, 198, 141 kg·ha-1·(210 d)-1, respectively

Evaluation of desertification intensity based on soil and water criteria in Jarghooyeh region

Desertification refers to land degradation phenomenon in arid, semi-arid and dry sub-humid areas, resulting from various factors including climate variation and human activities. For evaluation and mapping of desertification many research have been conducted leading to regional and local models. In this research, among different existing methods IMDPA‌ was selected and desertification intensity was evaluated on the basis of 2 criteria and 8 indices including: soil (soil depth, Electrical Conductivity, texture and gravel percentage) and water (groundwater table decrease, EC, Cl concentration, Sodium Absorption Ratio). Each criterion was assessed based on the selected indices which result in qualitative mapping of each criterion cased on geometric average of the indices. Finally, sensitive map of region was extracted using geometric average of all criteria. Thematic databases, with a 1:50000 scale resolution, were integrated and elaborated in a GIS based on arc/info8, arc view3.2 and especially ILWIS. Analysis of desertification criteria in Jarghooyeh region showed that among study criteria, soil criterion is a major problem in the study area with a geometric average of 2.25 which shows medium class while water criterion with a weighted average of 1.14 stands in low class of desertification. Also, the results showed that that Electrical Conductivity index with quantitative value of 3.54 classified in very high class of degradation, and ground water recession with quantitative value of 0.05 classified in low class of desertification were the most and the least effective factor on land degradation among studied indices respectively.

The role of grasslands in the formation of structural and spatial order of rural areas

The paper presents results of a two-year study on methane emission carried out in lysimetric station situated on Kuwasy peatland in the Biebrza River valley. The aim of this study was to estimate the amount of methane emission from peat-muck soil in relation to ground water level and fertilisation. Methane emission was determined with the chamber method using photo-acoustic probe. Methane emission significantly depended on the ground water level. The largest CH4 emission was found at full saturation of soil with water. With the decrease of ground water table the emission of methane decreased. Mineral fertilisation increased CH4 emission. At ground water table depth of 50 cm, CH4 emission from fertilised variant was by 42.3% bigger than from non-fertilised variant. Peat-muck soils overgrown by meadows in the Biebrza River valley were found to be an important source of methane emission. In the vegetation period at ground water table depths of 0, 25, 50 and 75 cm methane emission was 502, 361, 198, 141 kg·ha –1 ·(210 d) –1 , respectively.

Modeling radial growth increment of black alder ( Alnus glutionsa (L.) Gaertn.) tree

Nowadays it is extremely important to understand ecosystem function and its dynamics to predict future changes and consequently to perform appropriate measures. Hydromeliorations and subsequent decrease in groundwater table are thought to be a major reason for a decline in the vitality of black alder ( Alnus glutinosa (L.) Gaertn.) wetland forests in North-eastern Slovenia. In this study radial increments of trees were used as indicators of black alder forest function and its disturbances. The aim of the study was to build a model of annual radial increments of black alder trees, to use this model to identify environmental attributes that most importantly affect ecosystem's function and to predict changes in the forest function under different scenarios of environmental conditions in the future. The model was induced with a machine learning algorithm CIPER and it was based on the data about site conditions and applied management measures in the past 35 years. Groundwater levels in combination with the duration of sun radiation were identified as the most important environmental attributes affecting annual radial increments. Radial increments were the lowest in very wet and cloudy years. On the other hand, radial increments were decreased under drought stress as well. Changes in groundwater level and in duration of sun radiation, as well as increased oscillations of groundwater level, all cause important increase in oscillations of modeled radial increments, indicating higher stress. Radial increments were further negatively affected by late white frosts in the spring.