scholarly journals A low-cost subsurface drainage technique to enhance gully bank stability in the sub-humid highlands of Ethiopia

2021 ◽  
Vol 69 (3) ◽  
pp. 311-318
Author(s):  
Assefa D. Zegeye ◽  
Misganew Fentahun ◽  
Tilashwork C. Alemie ◽  
Tadele Amare
Keyword(s):  
Low Cost ◽  
Drainage System ◽  
Groundwater Table ◽  
Gully Erosion ◽  
Protective Measures ◽  
Sediment Yields ◽  
Initial Cost ◽  
Management Techniques ◽  
Bank Stabilization ◽  
Drainage Technique

Abstract Gully erosion is the leading cause of elevated sediment yields in the world. Few low-cost techniques are available for rehabilitating gullies. The objective of this research was to evaluate the applicability of a low-cost horizontal sub-surface drainage system for decreasing gully erosion by stabilizing gully banks. The study was conducted in the sub-humid Ethiopian highlands in two active gullies, one in a Vertisol and another in a Nitisol. One bank was drained with a plastic pipe, and the other bank acted as the control. The two opposite banks are hydrologically isolated from one another. The surrounding groundwater tables were continuously monitored for two years. Over two wet seasons, the average bank retreat in the Vertisol gully was 0.62 m for the control and 0.15 m for the drained bank. Similarly, in the Nitisol gully, in 1.1 m for the control and 0.29 m for the drained bank. The average groundwater table of the drained bank was 20% lower than the non-drained banks during the monitoring periods. These results suggest that bank dewatering maintained higher levels of stability of gully banks and promoted lower rates of bank retreat on both soil types. The initial cost of the dewatering treatments was significantly less than the conventional bank stabilization measures. Bank dewatering could be one of the technologies for gully rehabilitation. Gully management techniques in Ethiopia and elsewhere could benefit from integrating bank drainage with other physical and biological protective measures.

Application of AHP and Geospatial Techniques for Evaluating Gully Erosion Vulnerability in Benin City, Edo State, Nigeria

2021 ◽  
Vol 2 (1) ◽  
pp. 1-15
Author(s):  
Deborah Alaigba ◽  
Keyword(s):  
Drainage System ◽  
Pairwise Comparison ◽  
Road Construction ◽  
Gully Erosion ◽  
Control Measures ◽  
Pairwise Comparison Matrix ◽  
Geospatial Techniques ◽  
Benin City ◽  
The People ◽  
And Control

Gully erosion remains a major threat to the people of Benin City. This study applies Analytical Hierarchical Process (AHP) and geospatial techniques to evaluate vulnerability to gully erosion in Benin City, Nigeria. Five essential criteria were identified based on literature, and evaluation by experts. Pairwise Comparison Matrix (PCM) was obtained and weights for each of the PCM were determined using AHP. The consistency of generated weights obtained is not above 0.07. The method resulted in a gully erosion vulnerability model. Analysis of the model revealed that 52.1% (488.69Km2) of the area is vulnerable to gully erosion, while 3.4% (32.37 Km2) was found to be highly vulnerable to gully erosion. Fieldwork was conducted to establish the people’s perception and identify the causes and control measures for the gully erosion problem in the area. Findings on the major contributing factor that leads to the gully erosion formation showed that lack of drainage system accounts for 56.25%, improper land use practice account for 25%, and bad road construction (18.75%). About 50% of the respondents are of the view that an adequate drainage system would go a long way to mitigate the gully erosion. This present study has provided information on the state of gully erosion vulnerability in Benin City through mapping of vulnerable areas.

scholarly journals Review of Application and Innovation of Geotextiles in Geotechnical Engineering

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1774 ◽  
Author(s):  
Hao Wu ◽  
Chongkai Yao ◽  
Chenghan Li ◽  
Miao Miao ◽  
Yujian Zhong ◽  
...  
Keyword(s):  
Soil Pollution ◽  
High Performance ◽  
Low Cost ◽  
Geotechnical Engineering ◽  
Drainage System ◽  
High Strength ◽  
Present Situation ◽  
Soft Foundation ◽  
And Function ◽  
Erosion Protection

Most geotextiles consist of polymers of polyolefin, polyester or polyamide family, which involve environmental problems related to soil pollution. Geotextiles can be used for at least one of the following functions: Separation, reinforcement, filtration, drainage, stabilization, barrier, and erosion protection. Due to the characteristics of high strength, low cost, and easy to use, geotextiles are widely used in geotechnical engineering such as soft foundation reinforcement, slope protection, and drainage system. This paper reviews composition and function of geotextiles in geotechnical engineering. In addition, based on literatures including the most recent data, the discussion turns to recent development of geotextiles, with emphasis on green geotextiles, intelligent geotextiles, and high-performance geotextiles. The present situation of these new geotextiles and their application in geotechnical engineering are reviewed.

Septage dewatering in vertical-flow constructed wetlands located in the tropics

2001 ◽  
Vol 44 (2-3) ◽  
pp. 181-188 ◽  
Author(s):  
T. Koottatep ◽  
C. Polprasert ◽  
N. T.K. Oanh ◽  
U. Heinss ◽  
A. Montangero ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Low Cost ◽  
Drainage System ◽  
Oxygen Demand ◽  
Free Water ◽  
Total Solid ◽  
Solid Loading ◽  
Flow Mode ◽  
Vertical Flow ◽  
N Removal

Constructed wetlands (CWs) have been proven to be an effective low-cost treatment system, which utilizes the interactions of emergent plants and microorganisms in the removal of pollutants. CWs for wastewater treatment are normally designed and operated in horizontal-flow patterns, namely, free-water surface or subsurface flow, while a vertical-flow operation is normally used to treat sludge or septage having high solid contents. In this study, three pilot-scale CW beds, each with a surface area of 25 m2, having 65 cm sand-gravel substrata, supported by ventilated-drainage system and planting with narrow-leave cattails (Typha augustifolia), were fed with septage collected from Bangkok city, Thailand. To operate in a vertical-flow mode, the septage was uniformly distributed on the surface of the CW units. During the first year of operation, the CWs were operated at the solid loading rates (SLR) and application frequencies of, respectively, 80-500 kg total solid (TS)/m2.yr and 1-2 times weekly. It was found that the SLR of 250 kg TS/m2.yr resulted in the highest TS, total chemical oxygen demand (TCOD) and total Kjeldahl nitrogen (TKN) removal of 80, 96 and 92%, respectively. The TS contents of the dewatered septage on the CW beds were increased from 1-2% to 30-60% within an operation cycle. Because of the vertical-flow mode of operation and with the effectiveness of the ventilation pipes, there were high degrees of nitrification occurring in the CW beds. The nitrate (NO3) contents in the CW percolate were 180-250 mg/L, while the raw septage had NO3 contents less than 10 mg/L. Due to rapid flow-through of the percolates, there was little liquid retained in the CW beds, causing the cattail plants to wilt, especially during the dry season. To reduce the wilting effects, the operating strategies in the second year were modified by ponding the percolate in the CW beds for periods of 2 and 6 days prior to discharge. This operating strategy was found beneficial not only for mitigating plant wilting, but also for increasing N removal through enhanced denitrification activities in the CW beds. During these 2 year operations, the dewatered septage was not removed from the CW beds and no adverse effects on the septage dewatering efficiency were observed.

scholarly journals Hygiene Condition of Water Use and Sanitation Facilities at Urban Slums: Analysis of Port City Chittagong, Bangladesh / Wyposażenie Sanitarne W Slamsach Miejskich - Analiza Na Podstawie Miasta Portowego Chittagong, Bangladesh

2015 ◽  
Vol 16 (1) ◽  
pp. 153-166
Author(s):  
I. B. Muhit ◽  
S. Tasneem Chowdhury ◽  
Nurangir Nahid ◽  
M. F. Zaman
Keyword(s):  
Community Development ◽  
Water Supply ◽  
Low Income ◽  
Field Survey ◽  
Low Cost ◽  
Drainage System ◽  
Safe Drinking Water ◽  
Port City ◽  
Crucial Aspect ◽  
Power Development

Abstract Low income community development is the prerequisite for the overall development of a society. There are different kinds of parameters to widen community development, such as health, economic, social, a living pattern, etc. Sanitation condition is the crucial aspect that is directly or indirectly inter bond with all the parameters. To see the exact reasons behind brutal unhygienic sanitation conditions of water supply and latrine system in a low cost community, the Chittagong City Corporation area has been picked. Relevant data have been collected from field survey, consultancy with inhabitants, Chittagong City Corporation, Power Development Board, and WASA. To know the possible reasons behind the water supply and germ-infested sanitation, state of a low cost community, this paper attempts to shed some light on the tribulations behind the scarcity of safe drinking water, dirt free as well as sustainable latrine and drainage system and offensive water management.

scholarly journals Institutional protocol to standardize the chest drainage system management, from surgery to nursing care, at a regional hospital in northern Paraná

2016 ◽  
Vol 38 (2) ◽  
pp. 173
Author(s):  
Amanda Carina Coelho de Morais ◽  
Maurício Medeiros Lemos ◽  
Vlaudimir Dias Marques ◽  
César Orlando Peralta Bandeira
Keyword(s):  
Prospective Observational Study ◽  
Drainage System ◽  
Pleural Space ◽  
Regional Hospital ◽  
System Management ◽  
Pleural Drainage ◽  
Chest Drainage ◽  
Drainage Time ◽  
Water Seal ◽  
Drainage Technique

The purpose of chest drainage is to allow lung re-expansion and the reestablishment of the subatmospheric pressure in the pleural space. Properly managing the drainage system minimizes procedure-related complications. This prospective observational study evaluated adult patients undergoing water-seal chest drainage, admitted to our hospital and accompanied by residents and tutors, aiming to check their care. One hundred chest drainages were monitored. The average age was 38.8 years old. The average drainage time was 6.7 days. Trauma was the prevalent cause (72%) for the indication of pleural drainage. The obstruction of the system occurred in 6% of the cases; 5% subcutaneous emphysema, 1% infection around the drain; 5% accidental dislodgement of the drain, and in 5% of the patients, there were some complications when removing the drain. Failures in chest drainage technique and management were present, and reflected in some complications that are inherent to the procedure, although it is known that there are intrinsic complications. This study aimed to assess the management of closed chest drainage systems and standardize the care provided in such procedure. 

The impact of selective commercial logging on stream hydrology, chemistry and sediment loads in the Ulu Segama rain forest, Sabah, Malaysia

1992 ◽  
Vol 335 (1275) ◽  
pp. 397-406 ◽  
Keyword(s):  
Rain Forest ◽  
Drainage System ◽  
Flood Plain ◽  
Sediment Yields ◽  
The Road ◽  
Sediment Loads ◽  
Commercial Logging ◽  
Three Stages ◽  
The Impact ◽  
Degree Of Recovery

Three stages of selective commercial logging in a 0.54 km 2 catchment in the Ulu Segama caused great changes in the output of sediment and water over a 27-month period from June 1988. The ratio of monthly suspended sediment yield from the logged catchment to that from a nearby undisturbed catchment changed from the order of 1:1 before disturbance; to 4:1 after a logging road had been built across the head of the catchment; to 5:1 after logging within 37 m of the road; and to 18:1 in the five months after logging of the remainder of the catchment. A year after logging had ceased the largest monthly sediment yields of the whole period were only 3.6 times those of the undisturbed catchment, indicating a degree of recovery. Sediment accumulated in the channel bed and on the narrow flood plain remained to be evacuated, and gullies on abandoned logging trails continued to supply sediment to the drainage system.

scholarly journals Low-cost soil conservation technique for controlling gully erosion in the semi-arid area of the Free State province

2021 ◽  
Vol 49 (3) ◽  
pp. 136-142
Author(s):  
Joseph ◽  
Van der Westhuizen
Keyword(s):  
Soil Conservation ◽  
Potable Water ◽  
Negative Impact ◽  
Low Cost ◽  
Gully Erosion ◽  
Reference Points ◽  
Control Measures ◽  
Soil Productivity ◽  
Vegetation Types ◽  
Demonstration Site

In South Africa, soil erosion is a major problem confronting natural resources. Gully erosion has a huge negative impact on soil productivity and potable water supplies, while measures to control it are expensive. Sannaspos farm which has been threatened by gully erosion was selected as a demonstration site for controlling gully erosion using low-cost control measures. The main aim of this study was to control gully erosion resulting in improved rangeland production. The technique entailed the use of old tyres and bags filled with soil. Three reference points were selected along a 240 m gully in August 2016 and monitored over 42 months. After 17 months (January 2018), gully depth decreased from 70 to 34 cm, 45 to 20 cm and 35 to 19 cm at the three reference points. After 24 months (August 2018) gully depth further decreased from 34 to 27 cm, 20 to 14 cm, and 19 to 10 cm for the three points. Thirty months after installing control measures (February 2019), the gully was sealed at all reference points. By February 2020 (42 months after initiation of the trial), the entire gully was sealed and covered with various vegetation types. Use of this low-cost method to control gully erosion is recommended under similar conditions.

scholarly journals Erosion rates and sediment yields of glaciers

1996 ◽  
Vol 22 ◽  
pp. 48-52 ◽  
Author(s):  
Jim Bogen
Keyword(s):  
Water Pressure ◽  
Water Discharge ◽  
Drainage System ◽  
Sediment Concentration ◽  
Pressure Drops ◽  
Sediment Yields ◽  
Erosion Rates ◽  
Slow Moving ◽  
The Relationship ◽  
Subglacial Drainage

Sediment yields and glacial erosion rates are evaluated for four Norwegian glaciers during the years 1989-93. Annual erosion rates were determined from measurements of sediment load and water discharge in glacial meltwater rivers. The mean sediment yield and the corresponding erosion rate of the valley glaciers Engabreen and Nigardsbreen were found to be 456 t km−2year−1(0.168 mm year−1) and 210 t km−2year−1(0.078 mm year−1), respectively. A small and slow-moving cirque glacier Øvre Beiarbre yielded a rate of 482 t km−2year−1(0.178 mm year−1), and the sub-polar Svalbard glacier Brøggerbreen yielded 613 t km−2year−1(0.226 mm year−1). The erosion rates are low compared to glaciers elsewhere. There are also considerable variations in sediment yields at each glacier from year to year. However, different factors are found to control the variability on each individual glacier. Analysis of the relationship between water discharge and sediment concentration in meltwater rivers suggests that changes in subglacial drainage systems cause variations in sediment availability and the way sediments are melted out from the ice. When water pressure drops, the drainage system in fast-moving, thick valley glaciers deforms at a more rapid rate than in thin, slow-moving ones. New volumes of debris-laden ice are thus more readily available for melting when water pressure next increases. Beneath the thin, slow-moving Øvre Beiarbre, single years with high transport rates and evacuation of sediment are followed by periods of low availability lasting for 2 years or longer. It is suggested that this pattern results from exhaustion of sediment in a stable drainage system, with more sediment becoming available when the position of the subglacial drainage system is changed.

scholarly journals Modelling soil salinity in Oued El Abid watershed, Morocco

2018 ◽  
Vol 37 ◽  
pp. 04002 ◽  
Author(s):  
El Mouatassime Sabri ◽  
Ahmed Boukdir ◽  
Ismail Karaoui ◽  
Abdelkrim Arioua ◽  
Rachid Messlouhi ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Regression Model ◽  
Soil Salinity ◽  
Early Stage ◽  
Landsat Imagery ◽  
Low Cost ◽  
Drainage System ◽  
High Accuracy ◽  
Anthropogenic Factors ◽  
Moderate Amount

Soil salinisation is a phenomenon considered to be a real threat to natural resources in semi-arid climates. The phenomenon is controlled by soil (texture, depth, slope etc.), anthropogenic factors (drainage system, irrigation, crops types, etc.), and climate factors. This study was conducted in the watershed of Oued El Abid in the region of Beni Mellal-Khenifra, aimed at localising saline soil using remote sensing and a regression model. The spectral indices were extracted from Landsat imagery (30 m resolution). A linear correlation of electrical conductivity, which was calculated based on soil samples (ECs), and the values extracted based on spectral bands showed a high accuracy with an R2 (Root square) of 0.80. This study proposes a new spectral salinity index using Landsat bands B1 and B4. This hydro-chemical and statistical study, based on a yearlong survey, showed a moderate amount of salinity, which threatens dam water quality. The results present an improved ability to use remote sensing and regression model integration to detect soil salinity with high accuracy and low cost, and permit intervention at an early stage of salinisation.

scholarly journals A New Perspective to Explore the Hydraulic Connectivity of Karst Aquifer System in Jinan Spring Catchment, China

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1368 ◽  
Author(s):  
Zhengxian Zhang ◽  
Weiping Wang ◽  
Shisong Qu ◽  
Qiang Huang ◽  
Shuai Liu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Karst Aquifer ◽  
Groundwater Table ◽  
Karst Groundwater ◽  
Groundwater Exploitation ◽  
Aquifer System ◽  
Regional Hydrogeology ◽  
Karst Aquifer System ◽  
Spring Catchment

Investigating the hydraulic connectivity of a complex karst aquifer system is an important research topic for sustainable operation and optimization layout of karst groundwater exploitation and recharge. However, the identification of preferential sites of recharge and exploitation is usually subject to regional hydrogeology conditions and the mechanisms of recharge and exploitation. The conventional research methods of hydraulic connectivity often have some limitations. In this study, we developed an improved grey amplitude relation model to explore the hydraulic connectivity in Jinan spring catchment and presented a quantized evaluation index water table fluctuation relation degree (WTFRD) using karst groundwater table data in Western Jinan and Jinan spring groups from 2014 to 2017. Results showed that the total WTFRD was 0.854 between Western Jinan and Jinan spring groups when the external distraction for karst groundwater table was the smallest, which was in high relation degree grade. Meanwhile, the change rules of karst groundwater table in the two sites were basically the same. Accordingly, a high connectivity occurred between the two karst aquifers from a statistical perspective, and further illustrated that Western Jinan could be selected as preferential experiment sites. A comprehensive case in Jinan spring catchment indicated that the WTFRD provided a preliminary idea to investigate hydraulic connectivity quantitatively. This method could be considered as a pre-study of the conventional experiments to form a high-efficiency and low-cost combined method, which has great potential and merits further study.

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