Drainage Channels Research Articles

Research on enhancing separation of ultra‐fine droplets using turbulators between adjacent demister plates in WFGD systems

AbstractTo enhance the performance of demister applied in wet flue gas desulphurization systems, flow turbulators are equipped between adjacent plates to reconstruct flow field. Both experimental and numerical approaches are employed to investigate the influence of various kinds of turbulator configurations upon removal of droplets within the range of 5–50 μm obeying Rosin‐Rammler distribution. Turbulators including spoiler, square column, concave groove, perforated concave groove, and triangular and cylinder columns are compared, among which spoiler provided the highest overall efficiency while square column yields the best graded efficiency for 5 μm droplets group. Furthermore, moving the spoiler towards the core region of the demister ducts received better performance due to augmented interaction between spoiler and drainage channels, which performed an essential role in droplets collection. Based on this knowledge, spoilers are optimized by changing their angle of attack and size; the result is positive since overall separation efficiency can be improved to 100%, along with graded efficiencies for 10 and 5 μm groups achieving 95.97% and 27.26%, respectively, much higher than those of baseline demister without turbulators. This study indicates that inertial‐based demisters have great potential in separating ultra‐fine droplets through reorganizing turbulence field, thus extra system loss can be avoided by abandoning additional filter components.

Numerical Simulation of Surface Subsidence and Fracture Evolution Caused by Pulang Copper Mine Mining

Subsidence of the earth’s surface induced by mining activities has always been a critical concern in the relevant research fields. This subsidence disrupts the original geological structures and can lead to secondary geological hazards, environmental degradation, and threats to human lives and property. An in-depth investigation of this issue led to us using the three-dimensional finite-difference numerical simulation software FLAC3D 6.0 in this study. The research focuses on the Prang Copper Mine subsidence area in Yunnan Province, China, with a particular emphasis on the comprehensive analysis of the formation mechanisms of a large-scale crack appearing on the south side of the subsidence area. The study also includes a predictive analysis of the future development trends of this crack. The simulation results indicate that the crack formation was a consequence of the combined effects of uneven surface subsidence induced by underground structural interfaces and underground mining activities. As mining activities continued, the non-uniform subsidence of the surface intensified. The northward (Y-axis) displacement difference of characteristic points A and B on both sides of the crack continuously increased, signifying the widening of the crack. Mining activities also influence the displacement in the X-axis direction, potentially posing risks to support structures on either side of existing drainage channels. Therefore, effective control measures are warranted. Furthermore, this study highlights the possibility that new mining activities may further exacerbate subsidence on the south side of the subsidence area. This research provides valuable insights into the complexity of surface subsidence and its associated risks, offering guidance for mining activity planning and safety measures.

ANALISIS KAPASITAS AIR PADA SALURAN DRAINASE DI JALAN ANTASURA DAERAH PEGUYANGAN KAJA DENPASAR UTARA

ANALISIS KAPASITAS AIR PADA SALURAN DRAINASE DI JALAN ANTASURA DAERAH PEGUYANGAN KAJA DENPASAR UTARA

High toxicity of agro-industrial wastewater on aquatic fauna of a South American stream: Mortality of aquatic turtles and amphibian tadpoles as bioindicators of environmental health.

The aim of this study was to characterize an aquatic system of Santa Fe province (Argentina) receiving wastewater from agro-industrial activities (mainly dairy) by in situ assessment (fauna mortality, physicochemical, microbiological, and pesticide residues measurement), and ecotoxicity bioassays on amphibian tadpoles. Water and sediment samples were obtained from the Los Troncos Stream (LTS), previous to the confluence with the "San Carlos" drainage channel (SCC), and from the SCC. Biological parameters (mortality and sublethal biomarkers) were used to evaluate ecotoxicity during 10-day exposure of Rhinella arenarum tadpoles to LTS and SCC samples. Nine pesticides were detected in both LTS and SCC. Chemical and biochemical oxygen demand, ammonia, and coliform count recorded in SCC greatly exceeded limits for aquatic life protection. At SCC and LTS after the confluence with SCC, numerous dying and dead aquatic turtles (Phrynops hilarii) were recorded. In the ecotoxicity assessment, no mortality of tadpoles was observed in LTS treatment, whereas total mortality (100%) was observed in SCC treatments in dilution higher than 50% of water and sediment. For SCC, median lethal concentration and the 95% confidence limits was 18.30% (14.71-22.77) at 24 h; lowest-observed and no-observed effect concentrations were 12.5% and 6.25%, respectively. Oxidative stress and neurotoxicity were observed in tadpoles exposed to 25% SCC dilution treatment. In addition, there was a large genotoxic effect (micronuclei test) in all sublethal SCC dilution treatments (6.25%, 12.5%, and 25%). These results alert about the high environmental quality deterioration and high ecotoxicity for aquatic fauna of aquatic ecosystems affected by agro-industrial wastewater. PRACTITIONER POINTS: Great mortality of turtles was observed in a basin with a high load of agro-industrial wastewater. San Carlos Channel (SCC), where effluents are spilled, is environmentally deteriorated. The water-sediment matrix of SCC caused 100% lethality in tadpoles. SCC dilutions caused neurotoxicity, oxidative stress, and genotoxicity on tadpoles.

Storm water management model to evaluate urban inundation in Lowokwaru and Blimbing sub-catchments in the city of Malang

In the city of Malang, which is a highland area, there are still floods, including Blimbing and Lowokwaru sub-districts. One of the causal factors is the change of undeveloped areas becoming relatively large built-up areas in the Upper Brantas sub-watershed, from initially 20.5% in 2000 to 69.6% 20 years later. This change also impacts the transformation of irrigation canals that once irrigated rice fields, causing them to shift their function into drainage channels that carry runoff water toward natural channels (natural drainage). Consequently, the existing canal conditions cannot accommodate the runoff water. The research employed an approach that involved analyzing floodwater management models using the Storm Water Management Model (SWMM 5.1) and surveying existing canal data. The analysis results revealed that, within the studied areas of Blimbing Village and the Blimbing Catchment Area, 10 out of the existing 170 drainage channels were incapable of handling the discharge associated with rainfall intensities designed for return periods of 5 years (112.48 mm/day) and ten years (117.09 mm/day). In the Lowokwaru Catchment Area, it was evident that 18 out of the 216 existing canals experienced overflow events with designed flood discharge for 5-year and 10-year periods.

Centrifuge modeling of a large-scale surcharge on adjacent foundation

This study investigates the ground and structural response of adjacent raft foundations induced by large-scale surcharge by ore in soft soil areas through a 130g centrifuge modeling test with an innovative layered loading device. The prototype of the test is a coastal iron ore yard with a natural foundation of deep soft soil. Therefore, it is necessary to adopt some measures to reduce the influence of the large-scale surcharge on the adjacent raft foundation, such as installing stone columns for foundation treatment. Under an acceleration of 130 g, the model conducts similar simulations of iron ore, stone columns, and raft foundation structures. The tested soil mass has dimensions of 900 mm × 700 mm × 300 mm (length × width × depth), which is remodeled from the soil extracted from the drilling holes. The test conditions are consistent with the actual engineering conditions and the effects of four-level loading conditions on the composite foundation of stone columns, unreinforced zone, and raft foundations are studied. An automatic layer-by-layer loading device was innovatively developed to simulate the loading process of actual engineering more realistically. The composite foundation of stone columns had a large settlement after the loading, forming an obvious settlement trough and causing the surface of the unreinforced zone to rise. The 12 m surcharge loading causes a horizontal displacement of 13.19 cm and a vertical settlement of 1.37 m in the raft foundation. The stone columns located on both sides of the unreinforced zone suffered significant shear damage at the sand-mud interface. Due to the reinforcement effect of stone columns, the sand layer below the top of the stone columns moves less. Meanwhile, the horizontal earth pressure in the raft foundation zone increases slowly. The stone columns will form new drainage channels and accelerate the dissipation of excess pore pressure.

Kinetic energy correction coefficient for rectangular drainage channels

In urban water supply and drainage systems, rainwater channels or pipes are rectangular in design to help control the flow rate and adapt well to limited space. When the Bernoulli equation in fluid mechanics is used to solve the head loss of rectangular pipelines, the velocity parameter used in the kinetic energy term is usually the instantaneous or average velocity of the section at a certain point. Given that this velocity parameter is in exponential form, the smaller the error is, the greater the impact on the result will be. Thus, the kinetic energy term must be corrected. This study focuses on establishing a cross section velocity distribution model in a rectangular pipe and deriving the kinetic energy correction coefficient through the velocity distribution. Based on the Navier–Stokes equation, the partial differential equation describing the velocity distribution is further refined and simplified. Combined with the boundary conditions of the pipeline, the method of separating variables and Fourier transform are used to solve the equation. An example shows how to establish the velocity distribution model and find the analytical solution. Finally, the analytical formula of the kinetic energy correction factor of different cross section parameters and fluid properties is derived. To verify the accuracy of the analytical formula, the Fluent numerical simulation software is used for empirical verification, and then the Deming regression method is used to analyze the error between the theoretical and experimental values. The regression results of the kinetic energy correction coefficient prediction model established in this study are consistent with the actual values, and the confidence interval reaches 95%. This work provides strong guidance for the prediction of the kinetic energy correction coefficient in fluid mechanics and has an important theoretical and practical value.

Hydrology Balance in Sustainable Land Development

Several cities in West Sumatra are in an alluvial system formation even though they are at an altitude above 350 m msl, for example, Kota Solok 350 m, Bukittinggi 900 m, and Padang 25 m msl. The growth of this city was initially safe from floods, but lately, it has often experienced flood disasters or disturbed the hydrological balance. This is presumably due to changes in land use. The city of Solok has lost 385 ha of rice fields so far, the city of Padang has lost 35 ha of rice fields/year, and Bukittinggi has lost nearly 200 ha of its total rice field area. When there is a land use change to a settlement, the amount of water required during rice cultivation becomes water that has to be disposed of, and this should affect the expansion of the drainage channel. If the water requirement for one growing season is at a value of 1,300 mm, with a length of time from soil processing to harvesting is 4 months, meaning that every month the rice fields need water as much as 1,251,250 m3, which is equivalent to 0.48m3/sec.

Effect of passive versus active abdominal drainage on wound infection after pancreatectomy: A meta-analysis.

Following pancreatic resection, there may be a variety of complications, including wound infection, haemorrhage, and abdominal infection. The placement of drainage channels during operation may decrease the chances of postoperative complications. However, what kind of drainage can decrease the rate of postoperative complications is still a matter of debate. The purpose of this research is to evaluate the efficacy of both active and passive drainage for post-operation wound complications. From the beginning of the database until November 2023, EMBASE, the Cochrane Library and the Pubmed database have been searched. The two authors collected 2524 related studies from 3 data bases for importation into Endnote software, and 8 finished trials were screened against the exclusion criteria. Passive drainage can decrease the incidence of superficial wound infection in postoperative patients with pancreas operation (Odds Ratio [OR], 1.30; 95% CI, 1.06-1.60 p = 0.01); No statistically significant difference was found in the incidence of deep infections among the two groups (OR, 1.51; 95% CI, 0.68-3.36 p = 0.31); No statistical significance was found for the rate of haemorrhage after active drainage on the pancreas compared with that of passive drainage (OR, 0.72; 95% CI, 0.29-1.77 p = 0.47); No statistically significant difference was found in the rate of death after operation for patients who had received a pancreas operation in active or passive drainage (OR, 0.90; 95% CI, 0.57-1.42 p = 0.65); On the basis of existing evidence, the use of passive abdominal drainage reduces postoperative surface wound infections in patients. But there were no statistically significant differences in the risk of severe complications, haemorrhage after surgery, or mortality. However, because of the limited sample size of this meta-analysis, it is necessary to have more high-quality research with a large sample size to confirm the findings.

The significant impacts of laundry wastewater on microplastics: a case study in a residential area

Microplastics (MPs) in urban drainage are a significant source of river pollution. Laundry waste, which can contain high levels of microfibers, is a potential source of MPs in urban drainage. This study investigated the abundance and characteristics of MPs in urban drainage channels in Ketawanggede Village, Malang City, Indonesia. The research involved stages such as inorganic and organic separation using Fe2SO4.7H2O and H2O2, density-based MPs separation, and analysis of abundance, size, color, and polymer through microscopy and FTIR. Statistical testing was performed using the Kruskal-Wallis Test in RStudio. The results showed that the abundance of MPs increased with distance from the river, with the highest abundance found at location 4 (267.44 particles/L). The MPs were dominated by small particles (<1 mm), fibers (58%), and transparent (74.3%) in color. The type of polymer was mostly polypropylene (PP) and nylon. The study also found that the abundance of microfibers was significantly higher at locations 2 and 3 (where laundries were located) compared to location 1. This suggests that laundry waste is a significant source of microfibers in urban drainage.

Planning For Kucica Residential Drainage System in South Tangerang City Using SWMM Modelling

Planning an efficient drainage facility in residential areas is necessary to drain run-off water on the surface. To minimize the potential for inundation that can cause flooding. This research aims to design an efficient drainage system in one of the residential areas in BSD and to analyze the ability of drainage channels using the EPA SWMM 5.1 application for a 10-year return period. The results of this study for secondary channels with a maximum discharge plan of 0.101 m3/s can use a U-Ditch with dimensions of 30 cm × 40 cm, while primary channels with a maximum discharge plan of 0.288 m3/s can use a U-Ditch with dimensions of 40 cm × 60 cm. In this analysis only taking into account rainwater run-off from household sewage is not taken into account. In the main channel, using retention pond only can reduce around 12% of maximum discharge, so the alternative of flood prevention for this residential area can be implemented by using bio pore holes, which reduce 27.85% of maximum discharge. From these analyses, it can be concluded that the drainage system design can already accommodate the flood discharge, and adding retention pond does not affect decreasing flood discharge on the main channel too much.

PERENCANAAN SISTEM JARINGAN DRAINASE DI DESA KARANG DIMA KECAMATAN LABUAN BADAS KABUPATEN SUMBAWA BESAR

Structurally, the drainage in Buin Pandan Hamlet is generally masonry in cement, but due to poor planning, the water flowing on the road and also the planned drainage channel is not in accordance with the water discharge so that water overflows from the drainage channel, which is in Dusun Buin. Pandan, aims to determine whether the current condition of the drainage system is appropriate. After the research has been done, it is known that the value of Cv = 0.485, the value of C_s = 0.026 and C_k = 3.973, it can be concluded that in planning this drainage system the type III log method is used and the rainfall intensity is 0.229 mm/hour in Buin Pandan Hamlet. Then a calculation is carried out with the aim of knowing whether Qr &lt; Qs or Qr &gt; Qs in the drainage in Buin Pandan Hamlet and it is known that the difference between Qr = 5.46 (m^3/s) and Qs = 0.60 (m^3/s) is in the drainage. With steps that can be taken to prevent flooding, namely by re-planning the drainage channel. From the results of the re-planning of the drainage channel, the value of the channel capacity Qs is 5.86 (m^3/s) and the size of the channel that can accommodate water discharge is 1 m wide and 1.60 m high. Channels planned for the same channel, namely open rectangular channels, only have different dimensions.

EVALUASI SISTEM DRAINASE DI KAWASAN PEMUKIMAN PENDUDUK WILAYAH KAMPUNG IRIAN KELURAHAN SEKETENG KABUPATEN SUMBAWA

Jalan Tongkol area, Seketeng District, Sumbawa Regency, NTB. This is a road frequently used by residents. The drainage channel on Jalan Tongkol, Seketeng District, is unable to withstand the flow of air during heavy rain. This writing aims to analyze the feasibility of existing channel dimensions and identify the causes of the current accumulation of air conditions. This study was carried out by carrying out hydrological and hydraulic analysis. Hydrological analysis includes rainfall data, rain intensity using the Mononobe formula and flood discharge using the Rational formula. Next, calculate the flood discharge by expanding the Catchment Area area, the flow coefficient value and the rain intensity during the concentration time using the equation Tc=Td+To. The rainfall value used to calculate rainfall intensity is the average maximum daily rainfall value from 2011 to 2020 at the BBMKG Station in the Sultan Kaharuddin area, Sumbawa Besar.

Formation mechanism of a disaster chain in Loess Plateau: A case study of the Pucheng County disaster chain on August 10, 2023, in Shaanxi Province, China

Under the heavy rainfall risk due to global warming, a new trend has emerged in geological disasters of loess, which have often evolved into a chain form of disaster chain of loess (DCL) in recent years. The DCL is characterized by multiple, hidden, catastrophic, and complex characteristics that seriously affect the construction and operation of large-scale infrastructure on the Loess Plateau. To understand the formation mechanism of a disaster chain of loess, we took the Shiyangpo DCL, a typical disaster chain occurring recently on the Loess Plateau, as an example to investigate the geomorphic features and deformation characteristics of DCL using new technologies and methods such as Unmanned Aerial Vehicle (UAV) mapping and Geographic Information Systems (GIS) spatial analysis technology. A series of special laboratory tests considering the vibration of the loess subgrade was conducted to explore the changes in physical and mechanical properties of loess samples in the study area under natural, saturated, and vibration conditions. Additionally, the trigger factors and evolution process of this DCL were analyzed, and the formation mechanism of recently emerging typical DCL was revealed as well. The triggering factors of the disaster were summarized as follows: loess nature, heavy rainfall, irrigation, irrational excavation, incomplete drainage channels, and long-term vehicle vibration of roadbeds. Furthermore, extreme rainfall was identified as the primary inducing factor of Shiyangpo DCL. Finally, the development and evolution of Shiyangpo DCL were divided into five stages: the formation of the loess sinkhole stage, the occurrence of the loess subsidence stage, the occurrence of the loess collapse stage, the occurrence of the loess landslide stage, and the formation of river-blocking and dammed lake stage. This study reveals the cause and evolution process of the newly emerged DCL in the Loess Plateau, and the new techniques and methods involved can provide references for the theoretical research and prevention of loess geological disasters in other places.

Reducing the dynamic impact of a landslide on buildings and transport structures in the village of Toktogul, Uzgen district of the Kyrgyz Republic

In the Kyrgyz Republic, there is a significant increase in landslide activity against the backdrop of ongoing climate change, especially in the southern mountainous regions of the country. The volume of soil during a landslide in this region can reach tens and hundreds of thousands of cubic meters, and in some cases more. The rate of landslide displacement ranges from several meters per year to several meters per second. The purpose of this study is to unload the landslide area to protect the population, roads and other structures of the village of Toktogul, Uzgen district of the Kyrgyz Republic. This landslide area was studied on the basis of field research on the ground and the results of desk work. The sliding of soil masses in the area can cause destruction and debris of residential and administrative buildings, roads and power lines, as well as injury and death. Considering the equilibrium of the system of forces acting on the subsidence soil mass of the slope section and analyzing them, measures for unloading the landslide body in this section are proposed. The proposed longitudinal profiles of drainage channels to reduce the moisture content of subsidence soil and transverse profiles of developed soil to reduce the weight of subsidence soil are presented. Based on the results of processing research data and analysis, it is recommended to reduce the weight of unstable (subsidence) soil by stepwise development along the slope of the site and transporting it up to 5 km for subsequent brick production. It is also recommended to protect subsidence soil from waterlogging by installing drainage channels. Based on the results of the research, a real project was developed to protect the site from landslides near the village of Toktogul. The proposed measures make it possible to reduce the risk of a landslide in the area under consideration using methods and technical means that are inexpensive and accessible to government agencies and local administrations.

Morphometric Analysis of Dachigam Drainage Basin Using Geo-Spatial Technology (GST)

The examination of morphometric parameters through quantitative analysis proves highly valuable in assessing river basins, prioritizing watersheds for soil and water conservation, and natural resources management. In this study, an in-depth analysis of the Dachigam Catchment has been conducted, focusing on the quantification of various morphometric parameters. The research employs Geographic Information System (GIS) techniques to assess morphometric parameters in the micro-watersheds of the Dachigam Catchment. Linear and areal morphometric parameters were systematically derived and tabulated based on linear and shape characteristics of drainage channels, utilizing GIS and topographical maps (scale 1:50,000). The morphometric analysis conducted in the Dachigam catchment indicates that the basin has an elongated shape, suggesting that peak discharges would generally exhibit a flat profile and take time to rise. The drainage network within the basin is predominantly of the dendritic type, signifying a degree of homogeneity in texture. The slope analysis shows that the Dachigam watershed has a significant amount of steep terrain, ranging from 0 to 74.63%. The majority of the area falls within the 24 to 35% slope range. Examination of the aspect indicates that slopes oriented towards the south and southwest are the most prevalent in the basin. The watershed's mean bifurcation ratio is 1.71. This low ratio suggests that the watershed hasn't experienced significant distortion. In contrast, high bifurcation ratios exceeding 5 typically indicate distorted drainage patterns. The research illustrates how remote sensing and GIS methods can effectively analyze watershed morphometrics. These techniques offer valuable insights for planners and decision-makers involved in watershed-level planning and drainage basin management.

Transparent Structures for ZnO Thin Film Paper Transistors Fabricated by Pulsed Electron Beam Deposition.

Thin film transistors on paper are increasingly in demand for emerging applications, such as flexible displays and sensors for wearable and disposable devices, making paper a promising substrate for green electronics and the circular economy. ZnO self-assembled thin film transistors on a paper substrate, also using paper as a gate dielectric, were fabricated by pulsed electron beam deposition (PED) at room temperature. These self-assembled ZnO thin film transistor source-channel-drain structures were obtained in a single deposition process using 200 and 300 µm metal wires as obstacles in the path of the ablation plasma. These transistors exhibited a memory effect, with two distinct states, "on" and "off", and with a field-effect mobility of about 25 cm2/Vs in both states. For the "on" state, a threshold voltage (Vth on = -1.75 V) and subthreshold swing (S = 1.1 V/decade) were determined, while, in the "off" state, Vth off = +1.8 V and S = 1.34 V/decade were obtained. A 1.6 μA maximum drain current was obtained in the "off" state, and 11.5 μA was obtained in the "on" state of the transistor. Due to ZnO's non-toxicity, such self-assembled transistors are promising as components for flexible, disposable smart labels and other various green paper-based electronics.

Comparative analysis of adaptability of open TBM small curve turning radius

Aiming at the problems of difficult operation and low excavation accuracy of open TBM in the process of small curve cornering, the structural mechanism, and motion characteristics of the traditional Horizontal main beam type TBM and the new 8-SPS V-type TBM mainframe were compared and studied. Based on the drainage channel project of a pumped storage power station, the factors affecting the minimum turning radius of TBM were analyzed by establishing two TBM main engine turning direction models. Secondly, the design of two open TBM mainframes with a diameter of ϕ3530 mm is improved. Finally, the relationship between the displacement and velocity change between the cutterhead and the propulsion cylinder under the straight-line boring condition and the small curve turning boring condition of TBM was analyzed by ADAMS software. The results show that when the tunnel design axis has a large turning radius and is dominated by straight segments, the TBM propulsion system with horizontal main beam type has higher excavation efficiency. The 8-SPS V-type TBM cutterhead attitude change is more flexible, which is more suitable for complex and changeable small curve corner boring. Moreover, the 8-SPS propulsion system is symmetrical, and the speed of each cylinder changes more gently during the turning process, the cylinder attitude of TBM is easy to control during the small curve turning and propulsion, the boring accuracy is higher, and the propulsion system compliance is better.

Analisis Faktor-Faktor Yang Mempengaruhi Permukiman Kumuh Ditinjau Dari Kriteria Kekumuhan Drainase (Studi Kasus: Desa Tanjung, Kecamatan Hamparan Rawang)

Based on the Regulation of the Minister of Public Works and Public Housing of the Republic of Indonesia Number 14/PRT/M/2018 concerning Quality Improvement of Slum Housing and Slum Settlements. It is stated that slum housing is housing that has decreased the quality of its function as a dwelling, while slums are settlements that are not habitable due to building irregularity, high building density, and unqualified building quality and facilities and infrastructure. Conditions in Tanjung Village, Hamparan Rawang District, Sungai Full City. The condition of Tanjung village, Hamparan Rawang District, Sungai Full City, is classified as a slum, judging from environmental drainage, there are collapses in drainage channels, a lot of garbage is thrown and accumulates in drainage channels, reducing the effectiveness of drainage channels, the amount of development in the area, and other bad conditions. The purpose of this study is to find out what factors affect drainage slums in Tanjung Village, Hamparan Rawang District, Sungai Full City, look for dominant factors and find strategies to prevent or minimize the occurrence of drainage slums in Tanjung Village, Hamparan Rawang District, Sungai Full City for the present and the future. This study used quantitative methods by distributing questionnaires to respondents. The results of the research conducted there are 5 factors that affect drainage slums, namely the inability of drainage to drain water runoff, unavailability of drainage, disconnection with urban drainage systems, lack of maintenance of drainage, collapse of drainage.

Evolution of physical properties of a cultivated organic soil drained by drainage trench

Evolution of physical properties of a cultivated organic soil drained by drainage trench