Mitigation in erosion control and management of ex-mining water through revegetation and sustainable environmental management technologies

In the open-pit mining system that is being carried out by a company in the mining sector with gold and silver commodities, PT Citra Palu Minerals, land clearing can cause soil erosion which can lead to soil sedimentation, increased turbidity of water that will be released into the environment and potential entry soil eroded into the tailings pond at the Dry Tailing Management Facility (DTMF). Therefore, further action is needed to control erosion and sedimentation as well as water management so that the water to be released into the environment is following environmental quality standards that have been set by the government. Before determining and controlling erosion, it is necessary to know the rate of erosion that occurs at the research location, in this study the USLE (Universal Soil Loss Equation) method was used to predict the rate of erosion with the results obtained, namely 17.07 tonnes/ha on the North DTMF slopes and 21.04 tonnes/ha for DTMF South slopes. To reduce the rate of erosion, it is necessary to control erosion by revegetation of the land, create a water drainage system to the sedimentation pond and treat the collected water using biophytoremediation of land with the use of chemicals to accelerate the deposition process, constructed swamp forest to the latest sustainable technology recommended by the Indonesian Academy of Sciences (LIPI).

Performance Analysis of Krishi Bhagya Scheme in Agro-climatic Zone-3 of Karnataka

India has been predominantly an agricultural country. The progress of India is very much dependent on the development of agriculture. In recent years, effect of climate change seen in the form of long dry spells and heavy rains in rainfed areas causing drought and floods, respectively. However, these vagaries can be overcome by adopting soil conservation measures, changing cropping pattern, rain water harvesting etc., The present study was undertaken ‘to know the utilization pattern of the components by the KBS beneficiaries’ in Bagalkot and Vijayapura districts of Karnataka during 2017-2018 by the ex-post-facto research design with the sample size of 120 beneficiaries. The results revealed that contour bunds were constructed to increase ground water table (6.67 %) and control erosion (5.83 %). The probable reason might be that, majority of them having semi-medium land holdings. So, they are not ready to reduce the area on their productive lands. All the beneficiaries were constructed farm ponds to harvest rain water to provide protective irrigations in critical stages of crops to get good yield, collected water is also used for providing drinking water for humans and animals (77.50 %). All the beneficiaries installed diesel pump set to lift water from farm pond. Diesel pump is available in lower price and is compulsory to get subsidy under this scheme. So, the poor farmers can able to purchase and used for own purpose. Forty per cent of beneficiaries providing irrigations to the crops through sprinkler irrigations once in two weeks. So, that not even a drop is wasted and crop gets the required quantity of water at the right time for better yield. Thirty-five per cent of beneficiaries growing capsicum and tomato (15.00 %) in poly house. This study implies that KBS is facilitating the farming community not only in increasing production and productivity, but also in conserving natural resources to the greater extent. Therefore, the replication of the KBS for the non-beneficiaries is most desired to transform the socio-economic condition of the farming community at large.

Guest editorial -- Policies and practices in action to address soil erosion

This special issue is the second published after the Global Symposium on Soil Erosion (GSER, 15-17 May 2019, Rome, Italy) and includes contributions dealing with the 2nd theme of the GSER: Policies and practices in action to address soil erosion. While there is a good scientific understanding of the physical measures that can be used to prevent or mitigate soil erosion, the main constraints to progress often relate to policy development and or implementation as well as socio-economic aspects that provide limitations to implementation of sustainable soil management (SSM) practices including those directed to control erosion. There are no right or wrong answers to which policy or approach is most effective. Some combination of approaches needs to be adopted that work in the particular political, cultural, and socio-economic environment under consideration. The papers included in this special issue provide examples, from the national to local level, that could be adapted, or used, to improve uptake and implementation of SSM practices to prevent or reduce soil erosion. Regardless of what policy or plan is developed there has to be effective interaction with the local farmers and land managers as they are key to implementing any actions that will make a practical difference on the ground. Effective policies cannot be developed or implemented without bringing the land managers “on board” and the needs and limitations of the local farmers must be thoroughly understood and considered in any policy or plan development.

Geomats Used to Control Erosion on Reservoir Margins in Brazilian Hydroelectric Power Plants

Erosion on reservoir margins causes losses in the production of energy in Hydroelectric Power Plants (HPPs), making it necessary to implement control techniques that ensure the reduction in sediment deposits inside reservoirs. Among these techniques, geomats (geosynthetic erosion mats) are widely used to control erosion processes in slopes and watercourses. This material protects the margins both in the short and long term, contributing to strengthening the vegetation’s roots developed in the erosion areas. This paper studies the performance of geomats (with and without sack gabion) installed in six margin sections distributed in three experimental units of the Brazilian HPPs called Porto Colômbia and Volta Grande. The geomat performance was evaluated over four years of monitoring through a qualitative evaluation matrix and differential bathymetry. The influence of ultraviolet (UV) radiation on the degradation of geomats installed in each section (natural conditions), as well as on geomat ultraviolet-aging samples in the laboratory (accelerated conditions), was also evaluated using differential scanning calorimetry (DSC). The results showed no significant difference in performance between using the erosion control technique consisting only of geomats and the technique consisting of geomats and sack gabion. The highest bathymetric difference value obtained in the present study was 1.62 m in the experimental unit VG1, controlled with geomat without the application of sack gabion on the margin.

Influence of infiltration on soil erosion in green infrastructures

Rainwater-induced erosion in green geotechnical infrastructures such as a multilayered landfill cover system (MLCS) is a severe concern in the current era. Although vegetation is a proven measure to control erosion in the MLCS, there are other factors such as infiltration rate which influence the control of the phenomenon. Most of the existing studies are limited to understand influence of vegetation on erosion control or infiltration rate alone. In this study, an attempt is made to incorporate infiltration measurements alongside vegetation cover to understand erosion in surface layer of the MLCS. For this purpose, a pilot MLCS was constructed, and erosion of its surface soil was temporally evaluated through soil loss depth of eroded cover surface under the influence of natural as well as simulated rainfall conditions. Alongside erosion, the amount of vegetated cover was evaluated through photographic image analyses and infiltration rate was measured by mini disk infiltrometer. From the observed results, it is understood that soil erosion and infiltration rate depict a contrasting behaviour with growing vegetation. Antecedent moisture contents were observed to show greater influence on such erosion behaviour which was observed during the testing period. Such studies may be helpful to researchers and practicing engineers for understanding performance of various green geotechnical infrastructures and scheduling the maintenance services to increase the longevity of their layered soil systems.

Farmers’ awareness of the potential of vetiver grass for soil erosion control on Ogbomoso Agricultural Zone farmlands, south-western Nigeria

Background Soil degradation remains a serious threat to agricultural production. With increase downpour due to climate change effect, more farmlands are exposed to erosion. Therefore, ecologically sound strategies for erosion control are indispensable to farmers, to boost agricultural productivity. Results A multistage sampling technique was used to select the respondents for this study, and descriptive and inferential statistics were adopted to determine the farmers’ perception of the awareness, adoption and use of vetiver grass technology in controlling erosion in the study area. A total of four hundred valid questionnaires were subjected to analysis and the result shows that most of the farmers (29%) were between the ages of 41 and 50 years and the average age of the respondents stood at 45.5 years, implying that the farmers were in their productive and active age. Most of the respondents were male and married with an average household size of 5.2. Large number (76%) of the respondents had formal education, which the level ranged from primary to post-secondary education. Large proportion of the respondents engaged in private business as secondary occupation with an average income of $84.6 per cropping season. The effectiveness of vetiver grass adoption and use was significantly influenced by age (P < 0.1), gender (P < 0.01), marital status (P < 0.05), level of education (P < 0.01) and income of the respondents (P < 0.05). Most of the respondents within the ages of 41–50 years were aware of the erosion control potentials of vetiver grass and adopted the grass because it was cheap and affordable, easy to cultivate and maintain, and readily available and perceived to possess the potential effectiveness to control erosion. Conclusion Stakeholders are enjoined to increase the awareness of the vetiver grass for increased adoption and utilization, as many farmers were ignorant of the vetiver grass technology for erosion control in the study area.

Enhancing scour protection in river bends: a novel slotted bank-attached vane

One of the most effective approaches for bank control erosion is using bank-attached vanes. In spite of the superiority of the bank-attached vanes to spur dikes, the vanes' tips are still vulnerable to local scour caused by flow–structure interaction. In this study, slotted bank-attached vanes are proposed to reduce local scour at the tip of the triangular submerged vane. For this, a rectangular slot is created parallel to the chord of the vane with an area of ten percent of the effective area of the vane surface. Two types of conventional vanes and slotted vanes were installed at different angles of attack of 23, 30, 40 and 60 degrees in an arch flume. Experiments were carried out in clear water conditions with different flow regimes with Froude numbers of Fr = 0.287, 0.304 and 0.322. The results show that the slotted vane outperforms the conventional vane by reducing maximum scour depth by about 70, 20, 17 and 54 percent for different angles of attack of 23, 30, 40 and 60 degrees, respectively. The proposed slotted vane also resulted in reduction of scour hole volume around the vane and formed the scour hole away from the outer bank.