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Drainage in sugarcane cultivation in high-rainfall areas is of paramount importance because it affects sugarcane plants from planting, maintenance, and production. Poor drainage can damage plants and reduce productivity. This study was conducted at Bone Sugarcane Plantation, which typically has high annual rainfall; thus, drainage is necessary. The existing drainage channel cannot drain all surface runoff quickly and causes problems to sugarcane plants. Therefore, a study was conducted with the aim of designing the shape and size of drainage channels that can drain surface runoff quickly, have a strong structure, allows for an effective use of cultivated land by reducing headland for tractor turning, and maintains appropriate soil moisture. The research began by determining the saturated hydraulic conductivity of the soil using the Falling Head method. Surface runoff discharge was calculated using rational equations to determine the dimensions of the drainage channel. Rainfall intensity was determined from Intensity Duration Frequency curve which was constructed using Manonobe method. The results showed that the saturated hydraulic conductivity of the soil was 3.54 × 10−3 cm/s which is suitable with surface drainage. Rainfall intensity is estimated to be 201.33 mm/hour. The shape and dimensions of the drainage channel are parabolic with the largest width and depth of 1.70 m and 0.90, respectively. This study provides a practical method to solve drainage problems in sugarcane fields that apply full mechanization. In addition, the practical analysis used in this study can be adapted to analyze the design of drainage channel for other plantations or regions with similar constrains.

In this contribution, a simulation chain for the thermo-mechanical and hydromechanical analysis (surface drainage) of a pavement structure during its whole service life is applied to a typical asphalt pavement (Bk100) used for motorways in Germany. Transient load signals for each tyre position of a truck-trailer combination (vehicle) are generated from a multibody analysis of the vehicle driving on a motorway with rough pavement surface. Material model parameters are derived from experimental identification tests of asphalt materials. The model parameters are used together with a continuum-mechanical description of the asphalt material representing the thermo-mechanical material behaviour at the material scale. The material response of the pavement layers is integrated on the structural scale by using the finite element method (FEM) in combination with an arbitrary Lagrangian-Eulerian (ALE) formulation and equivalent tyre loads of a representative, finite element (FE) discretised truck tyre rolling on an FE discretised pavement section. Different scenarios of rut formation are computed by varying different influence factors (climate temperature, vertical tyre force, type of asphalt material of the surface layers etc.). During the subsequent hydromechanical analysis of the pavement, the simulated deformed geometry of the pavement surface is used to numerically compute surface drainage characteristics. [ABSTRACT FROM AUTHOR]

The proximity of urban and extensive agricultural areas to the rivers of the Atlantic watershed in Costa Rica contrasts with its unstable morphology. Additionally, changes on the rain regime have increased the frequency of natural disasters affecting regularly the nearby populations and the economy of the country. Detailed studies demonstrating the impact of rivers in urban areas and high agricultural activity are necessary to establish adequate flood mitigation and control measures. The present study shows a case study of the impact of a 25-year flood event on the flood plain of the Matina River in Costa Rica, by means of a bi-dimensional hydraulic modelling with the aim to contribute to the adequate management of land use and the establishment of protection measures in the study vregion. A digital elevation model, of the topography of the study area, obtained with a LIDAR device, and the estimation of the instantaneous peak flow was obtained with the statistical Weibull distribution for a return period of 25 years, allowed to provide satisfactory information for the flood analysis of complex combinations for surface drainage management. Two scenarios for flood management were analyzed: 1) increasing the dike height, and 2) early opening of an additional mouth at the river outlet during the flood events. The study demonstrated that none of the options were technically feasible and that decision makers should explore other flood mitigation alternatives.

Permeable pavement (PP) can be used to decrease urban surface runoff. However, few studies have been conducted to explore the runoff reduction effect of various structures of PP in the carriageway. In this study, several structures of PP used in the carriageway of sponge cities in China were investigated and divided into three types: surface drainage, base course storage and drainage, and fully permeable. Then, the runoff models were developed by Storm Water Management Model to simulate the effect of the three types under various rainfall recurrence periods. Results show that rainfall recurrence period, structure and thickness of the permeable layer were identified as the most influential factors in PP runoff reduction. The surface drainage can reduce total runoff depth and coefficient by more than 14%, and also delay runoff start time and duration by more than 40 minutes. Surface runoff in the base course storage and drainage can only be generated when recurrence period is 50 years. The fully permeable does not generate any runoff under all recurrence periods. Based on simulation results, a series of runoff coefficient values for PP were recommended to help the design and implementation of PP in mitigating urban waterlogging problems.

Regulation of surface runoff in urban areas with temporary delay by infiltration basins of rainwater in the places of their precipitation and with gradual drainage through the existing reservoirs of small diameters is the most appropriate under the conditions of intensive building development, wear and imperfection of surface drainage systems, especially combined sewerage. Evaluation of application conditions and basic parameters of infiltration basins in surface drainage regulation was carried out on the basis of own experimental studies of infiltration basin fragment with upper typical vegetation layer, numerical computer modeling of surface runoff formation in urban areas, its regulation using infiltration basins and analysis of previous studies. Its water absorption, filtration and clearing indicators were defined on the basis of experimental studies. The self-regenerative restoring function of a vegetative layer, working conditions under the flooded and not flooded conditions were established and defined. According to the amount of suspended solids, BOD, oxidation, pH and dissolved oxygen, the quality of rain runoff when filtering water through the upper vegetation layers of infiltration basins decreases to the normative values. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Arquitetura IMED is the property of Revista de Arquitetura IMED and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Drainage management is important in intensification of irrigated paddy rice production. This study assessed the effects of drainage intensity on water and nitrogen use efficiency and rice grain yield in a field experiment conducted during three seasons in Rwanda. The experiment comprised 12 plots with four blocks and three treatments: DS0.6 (0.6 m deep drain), DD11.2 (1.2 m deep drain, control structure open four times per week), and DD21.2 (1.2 m deep drain, control structure open two times per week). Outflow was calculated from water balance. Nitrogen (N) content in drainage water was determined weekly. Crop yield and N uptake were determined in grain and straw. In all seasons, grain yield was 61–131% higher, crop N uptake was 24–90% higher, harvest index (HI) was 24–65% higher and water use efficiency (WUE) was 50–150% higher in treatments DD11.2 and DD21.2 than in DS0.6. There was a decrease in soil carbon/nitrogen ratio at the end of Seasons 2 and 3. Recirculating straw to fields is thus necessary to replenish SOC for long-term soil fertility. A practical implication of the study is that managed deep drainage systems could enhance water use efficiency and rice grain yield in poorly drained paddy fields.

One of the major issues in road safety is the slipperiness of the topcoat surface of the road during rainfalls. The presence of water on the pavement surface reduces friction on the topcoat surface. In the absence of sufficient friction, accidents caused by slipping seem inevitable. A common phenomenon during rain is hydroplaning. The hydroplaning characteristics are affected by water film thickness, tire inflation pressure, pavement texture depth, surface hydraulic properties, and tire tread depth. The present study aims to determine the impact of superhydrophobic coating of octafluoropentyl methacrylate (OFPMA) on the hydroplaning risk and water layers thickness in asphalt pavements. For this purpose, a device for simulating rainy conditions on asphalt pavements was designed. The water flow velocity over a variety of uncoated and coated asphalt surfaces with various degrees of the superhydrophobic coating was measured and the hydroplaning speed was calculated. According to the results, the mean values of the hydroplaning speed of a vehicle on the coated asphalt samples were roughly 1.33 times greater than the uncoated asphalt samples. Furthermore, the outcomes in this paper indicated that superhydrophobic coatings could be an innovative method to mitigate hydroplaning risk and decrease water film thickness on pavements. [ABSTRACT FROM AUTHOR]

The problems of excess humidity in agricultural areas in Cuba are due to the combination of excessive rainfall, surfaces with little slope and soils with low infiltration, so the solutions to this problem are preferably directed to surface drainage. With a view to the above, the present work was directed to the determination of the design rains for a drainage system for the cultivation of citrus to develop on alluvial soils in areas of the Jiguaní Municipality in the Province of Granma; where the accumulated average annual rainfall reaches 1219 mm and the wettest month is the month of October, a total of 213 were studied and through the Thielsen method the most representative of the area under study was selected, from 27 years of Daily observations of the same that were grouped in periods of maximum rainfall of 1,2,3,4 and 5 days and in order to generate the height-duration-frequency curves and the Gumbel Type I distribution was used to obtain the rainfall of design for the calculation of runoff for return periods of 3, 5 and 10 years. By applying the Kolmogorv-Smirnov test, the veracity of the Gumbel distribution was verified with 95% confidence for the data used; while it was determined that the critical rainfall for the calculation of the runoff to be evacuated was 126.1 mm for a return period of five years and three consecutive days of rainfall. [ABSTRACT FROM AUTHOR]

Abstract Conservation and restoration of salt marsh ecosystems are becoming increasingly important because of the many ecosystem services they provide. However, the processes controlling salt marsh establishment and persistence, especially on bare tidal flats in muddy areas, remain unclear. As muddy sediments typically experience a restriction of soil drainage, we expect that a surface drainage relief due to a heterogeneity topography, as might occur on the edge of tidal channels, can facilitate the establishment of salt marsh vegetation on muddy tidal flats. By means of a manipulative field experiment, using “Mega‐Marsh Organ” mesocosms, we investigated the impact of surface drainage and elevation relative to mean sea level on (1) the survival of Spartina anglica seedlings from three different age classes: 1‐yr, 3‐month, and 1‐week; and (2) the growth performance of mature S. anglica marsh tussocks. S. anglica seedling survival, especially in the establishment phase, was positively affected by better surface drainage, increases of seedling age, and higher elevation relative to mean sea level. That is, the survival rate of S. anglica seedlings at the end of 6th week increased from 0% (at surface water undrained, 1‐week, 0 cm elevation) to 94.44% (at surface water drained, 1‐yr, 90 cm elevation). In contrast, surface drainage did not affect the performance of large S. anglica marsh tussocks, as only increased elevation relative to mean sea level was shown to affect S. anglica tussock growth in terms of plant height, shoot numbers, and dry biomass. Based on our findings, we proposed a conceptual model to understand how surface drainage‐driven feedbacks in a heterogeneous topography may be reinforced to induce salt marsh establishment in muddy systems. Further testing of present hypothesized model would be beneficial for insights into salt marsh establishment on tidal mudflats.

Conservation and restoration of salt marsh ecosystems are becoming increasingly important because of the many ecosystem services they provide. However, the processes controlling salt marsh establishment and persistence, especially on bare tidal flats in muddy areas, remain unclear. As muddy sediments typically experience a restriction of soil drainage, we expect that a surface drainage relief due to a heterogeneity topography, as might occur on the edge of tidal channels, can facilitate the establishment of salt marsh vegetation on muddy tidal flats. By means of a manipulative field experiment, using "Mega‐Marsh Organ" mesocosms, we investigated the impact of surface drainage and elevation relative to mean sea level on (1) the survival of Spartina anglica seedlings from three different age classes: 1‐yr, 3‐month, and 1‐week; and (2) the growth performance of mature S. anglica marsh tussocks. S. anglica seedling survival, especially in the establishment phase, was positively affected by better surface drainage, increases of seedling age, and higher elevation relative to mean sea level. That is, the survival rate of S. anglica seedlings at the end of 6th week increased from 0% (at surface water undrained, 1‐week, 0 cm elevation) to 94.44% (at surface water drained, 1‐yr, 90 cm elevation). In contrast, surface drainage did not affect the performance of large S. anglica marsh tussocks, as only increased elevation relative to mean sea level was shown to affect S. anglica tussock growth in terms of plant height, shoot numbers, and dry biomass. Based on our findings, we proposed a conceptual model to understand how surface drainage‐driven feedbacks in a heterogeneous topography may be reinforced to induce salt marsh establishment in muddy systems. Further testing of present hypothesized model would be beneficial for insights into salt marsh establishment on tidal mudflats. [ABSTRACT FROM AUTHOR]

Abstract This study examines whether catchment‐scale natural flood management (NFM) interventions could help to manage water levels in downstream urban watercourses and promote free discharge from surface drainage outfalls. A coupled modelling approach consisting of Dynamic TOPMODEL, HEC‐RAS, and Infoworks ICM models is used to characterise the response from a small Cambridgeshire catchment. Four different NFM scenarios (consisting of in‐channel woody debris and wider catchment afforestation) are defined. The attenuation of catchment response created by these measures is evaluated for an historic event and six different design storms. The consequent moderation of water depths at two downstream drainage outfalls is investigated with respect to maintaining free discharge from a surface drainage system. The case study results show that greatest reductions in the time of outfall inundation from NFM occur during frequent storm events (e.g., up to 5.75 hr during a 5‐year event). These reductions diminish with increasing storm severity but, by slightly desynchronising rural and urban responses, upstream interventions continue to have modest benefit for downstream drainage performance (e.g., preventing system capacity being exceeded during a 100‐year event). These results may interest water companies (increasingly involved in catchment‐scale NFM projects) looking to improve performance of surface water drainage.

Drainage management is important in intensification of irrigated paddy rice production. This study assessed the effects of drainage intensity on water and nitrogen use efficiency and rice grain yield in a field experiment conducted during three seasons in Rwanda. The experiment comprised 12 plots with four blocks and three treatments: DS0.6 (0.6 m deep drain), DD11.2 (1.2 m deep drain, control structure open four times per week), and DD21.2 (1.2 m deep drain, control structure open two times per week). Outflow was calculated from water balance. Nitrogen (N) content in drainage water was determined weekly. Crop yield and N uptake were determined in grain and straw. In all seasons, grain yield was 61–131% higher, crop N uptake was 24–90% higher, harvest index (HI) was 24–65% higher and water use efficiency (WUE) was 50–150% higher in treatments DD11.2 and DD21.2 than in DS0.6. There was a decrease in soil carbon/nitrogen ratio at the end of Seasons 2 and 3. Recirculating straw to fields is thus necessary to replenish SOC for long-term soil fertility. A practical implication of the study is that managed deep drainage systems could enhance water use efficiency and rice grain yield in poorly drained paddy fields. [ABSTRACT FROM AUTHOR]

This study examines whether catchment‐scale natural flood management (NFM) interventions could help to manage water levels in downstream urban watercourses and promote free discharge from surface drainage outfalls. A coupled modelling approach consisting of Dynamic TOPMODEL, HEC‐RAS, and Infoworks ICM models is used to characterise the response from a small Cambridgeshire catchment. Four different NFM scenarios (consisting of in‐channel woody debris and wider catchment afforestation) are defined. The attenuation of catchment response created by these measures is evaluated for an historic event and six different design storms. The consequent moderation of water depths at two downstream drainage outfalls is investigated with respect to maintaining free discharge from a surface drainage system. The case study results show that greatest reductions in the time of outfall inundation from NFM occur during frequent storm events (e.g., up to 5.75 hr during a 5‐year event). These reductions diminish with increasing storm severity but, by slightly desynchronising rural and urban responses, upstream interventions continue to have modest benefit for downstream drainage performance (e.g., preventing system capacity being exceeded during a 100‐year event). These results may interest water companies (increasingly involved in catchment‐scale NFM projects) looking to improve performance of surface water drainage. [ABSTRACT FROM AUTHOR]

Stone block pavements consist of discrete units placed closed together and embedded in a bound or unbound bedding layer according to a given laying pattern. Such pavements are widespread in historic and architecturally valuable urban centres. Design choices, including laying pattern, cross-sectional shape, and slope, are not exempt from causing inherent defects such as joint openings and height differences between adjacent elements, depending on the sizes of the individual stone blocks. Prior knowledge of the deviation of the actual surface from the ideal one allows such problems to be managed during the design, execution and validation phases of the work and is essential for resolving disputes between the client and the contractor. Following the analysis of a 3D virtual reconstruction of stone block pavements, the authors developed nomograms for the quantitative prediction of inherent geometric defects in relation to the parameters influencing their values. • Stone pavements have inherent defects such as joint opening and height differences between elements. • Size and shape of elements, laying patterns, cross-sectional slope and shape influence inherent defects. • The positions and values of the main inherent defects were determined. • Nomograms were developed to generalize the results for different design choices. [ABSTRACT FROM AUTHOR]

مقدمه مدیریت مناسب آب مهم­ترین عملیات در اراضی شالیزاری است که نقش مهمی در سودمندی سایر نهاده ­ها در کشت برنج دارد. زهکشی­ های میان ­فصل و پایان­ فصل دو عملیات مهم مدیریت آب در شالیزارها هستند به­ طوریکه اولی باعث افزایش عملکرد و دومی منجر به بهبود شرایط برداشت برنج می­شود. زهکشی زیرزمینی با فراهم کردن شرایط بهتر برای کشت زمستانه در این اراضی، می­تواند سبب تسهیل انجام عملیات­های مدیریتی مذکور در طول فصل کشت برنج شود. با این وجود، با توجه به هزینه زیاد و زمان­بر بودن آزمایش­های مزرعه­ ای، مدل­های شبیه­ سازی ابزارهای جایگزین مناسبی برای آنالیز اثرات گزینه­های مختلف مدیریت آب می­باشند. از میان مدل­های مختلف شبیه­ سازی، مدل Aquacrop مدلی است که جدیدا برای شبیه­ سازی اثرات مدیریت آبیاری توسعه یافت. این مدل در مقایسه با سایر مدل­ها، دقیق، توانمند و نیازمند داده­های کم می­باشد. برای گیاهان زراعی، مدل Aquacrop دارای مدلی از رشد است که مبتنی بر رابطه رفتار محافظتی زیست­ توده به ازای واحد تعرق گیاه می­باشد. مشخصه خاص دیگر این مدل، توصیف توسعه کانوپی به­ صورت پوشش سایه ­انداز هست تا شاخص سطح برگ. فراهانی و همکاران (Farahani et al., 2009)، با استفاده از مدل Aquacrop اثرات آبیاری کامل و کم آبیاری را بر پنبه در سوریه و اسپانیا بررسی کردند. آنها نشان دادند که، درمرحله واسنجی، پارامترهای اساسی مانند بهر ه­وری آب نرمال شده، پوشش سایه ­انداز و کل زیست­ توده باید برای شرایط مختلف اقلیمی، خاک، ارقام، روش­های آبیاری و مدیریت مزرعه مورد آزمایش قرار گیرد. در ایتالیا، گیاه آفتابگردان با استفاده از مدل­های Aquacrop، CropSyst و WOFOST ارزیابی شد. انحراف بین مقادیر مشاهده شده و شبیه­ سازی شده عملکرد دانه به ­وسیله مدل Aquacrop کمتر از میزان آن در دو مدل دیگر بود. مواد و روش­ها در این پژوهش، اثر تنش خشکی در شالیزارهای دارای سیستم­های زهکشی سطحی و زیرزمینی با استفاده از مدل AquaCrop ارزیابی شد. داده­ های مورد نیاز از پایلوت زهکشی زیرزمینی دانشگاه علوم کشاورزی و منابع طبیعی ساری طی فصول کشت برنج در سال­های 1390 و 1391 تهیه شد. مقدار تبخیر- تعرق مرجع با استفاده از ETo calculator 3.1 محاسبه شد. مقادیر ورودی پارامترهای هواشناسی روزانه شامل حداقل و حداکثر دمای هوا، حداقل و حداکثر رطوبت نسبی، ساعات آفتابی و سرعت باد در ارتفاع دو متری از ایستگاه هواشناسی و ETo calculator از سایت فائو تهیه شد. سیستم­های زهکشی عبارت بودند از: سه سیستم زهکشی معمولی شامل سیستم زهکشی با عمق زهکش 0/9 متر و فاصله زهکش 30 متر (D0.9L30)، سیستم زهکشی با عمق زهکش 0/65 متر و فاصله زهکش 30 متر (D0.65L30) و سیستم زهکشی با عمق زهکش 0/65 متر و فاصله زهکش 15 متر (D0.65L15)، یک سیستم زهکشی دو عمقی با فاصله زهکش 15 مترو اعماق زهکش 0/65و 0/9 متر به­ صورت یک در میان (Bilevel) و سیستم زهکشی سطحی (Control). واسنجی و صحت­سنجی مدل براساس اندازه­گیری­های مزرعه­ای انجام شد. با استفاده از مدل واسنجی شده، اثر آبیاری کامل (I1) و اعمال تنش خشکی در دوره­ های 22-16 (I2)، 29-23 (I3)، 36-30 (I4)، 43-37 (I5) و 50-44 (I6) روز بعد از نشاکاری، بر عملکرد و کارایی مصرف آب برنج و شوری ناحیه ریشه بررسی شد. نتایج و بحث اعمال تنش در دوره­ های I2، I5 و I6، سبب کاهش قابل‌توجه عملکرد و زیست‌توده برنج در مقایسه با I1 شد. با نزدیک شدن به مرحله خوشه­ دهی، تنش خشکی باعث کاهش بیشتر عملکرد برنج شد به‌طوری‌که متوسط کاهش عملکرد دانه برنج در اثر تنش در دوره ­های I2 تا I4، 5 درصد ولی در مراحل I5 و I6، 15 درصد بود. تنش آبیاری در دوره I2، کارایی مصرف در تیمارهای زهکشی سطحی و زیرزمینی را افزایش داد. در شرایط آبیاری کامل و زهکشی دوعمقی، مقدار آب مصرفی برابر 620/4 میلی­متر و کارایی مصرف آب برابر 0/65 کیلوگرم بر مترمکعب بود ولی در شرایط تنش خشکی در هفته سوم پس از نشا، مقدار آب مصرفی برابر 529 میلی­متر و کارایی مصرف آب برابر 0/71 کیلوگرم بر مترمکعب به دست آمد. همچنین، تنش خشکی سبب افزایش بیشتر شوری ناحیه ریشه برنج در تیمار زهکشی سطحی در مقایسه با تیمارهای زهکشی زیرزمینی شد. نتیجه ­گیری بر اساس نتایج، می­توان از مدل AquaCrop برای تعیین مناسب­ترین سیستم مدیریت آب‌کشت برنج از نظر میزان عملکرد محصول، کارایی مصرف آب و شوری ناحیه ریشه استفاده کرد.

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • An overview of drainage and salinization problems of irrigated lands is presented. • Various structural measures and their aptness for salinity control is presented. • Application and limitations of surface and subsurface drainage system are provided. • The aptness and restrictions of tile, mole, and vertical drainage are detailed. Abstract Convenient and sufficient water supply to crops is a necessity for sustainable food production to the rising total populace. Albeit adequate water supply is important for crop production, the surplus water in the rootzone is hurtful to plant development and yield. Poor drainage and associated salinization represent severe threats to the long-term sustainability of irrigated agriculture in several dry areas. Reducing soil submergence, salinity control, and making new land accessible for agriculture are the three main goals of agricultural drainage. Thus, an effective drainage system not only improves the existing agricultural lands but also brings new areas under cultivation. This paper provides an investigation of different structural and engineering measures adopted for the management of drainage and salinization problems of irrigated lands. The overview of drainage and salinization problems and the requirement of a drainage system are presented. Application and limitations of surface drainage system in agricultural areas and the processes involved in the removal of surplus water through subsurface drainage system are provided. The adaptability and limitations of tile drainage, mole drainage, and vertical drainage in managing the drainage and salinization problems of agricultural lands are also detailed in the paper. Finally, policy issues are discussed and some conclusions are provided. [ABSTRACT FROM AUTHOR]

In agricultural fields, soil erosion is usually associated to surface runoff. However, in drained fields, tile drains are additional pathways for soil particles. Few studies have quantified erosion in drained fields and they mainly focused on tile drained fields, without considering fields combining surface and tile drainage. These studies show high inter-site and inter-annual variabilities that highlight the need for more annual quantifications of erosion in drained fields. Consequently, it is still difficult to quantify the relative importance of the factors affecting soil erosion in drained fields. In addition to a comprehensive review of the existing studies of erosion through drainage, this study aims at quantifying surface and subsurface erosion in a 5 ha cultivated field combining surface and tile drainage. Suspended sediments (SS) and water fluxes have been monitored during two years (2019–2020 and 2020–2021) at a high temporal resolution (1 min), both at the outlet of the tile drain network and at the outlet of the surface drainage rill. SS yield was 0.49 t ha−1 and 1.08 t ha−1 in 2019–2020 and 2020–2021, respectively. During 2019–2020 and 2020–2021, tile drainage contribution to the total runoff was 46% and 21%, respectively and its contribution to SS yield was 9% and 11%, respectively. High temporal resolution measurements of runoff and SS concentrations showed the suspended sediment concentration in the surface drain runoff only increase by 17% from the first to the second study year. Conversely, for tile drainage, average suspended sediment concentrations increased by 260%. These variations and the increase of surface runoff rate suggest a shift in water and sediment connectivity at the field scale. Cropping practices could have generated a slumping of the soil surface during the second year and, at the same time, the development of a macropore network in the subsoil. Cropping practices induced changes of surface horizon characteristics and their impact on the hydrosedimentary behavior of drained soils need to be further studied. This study confirms previous results concerning the temporal dynamics of SS exports in a drained context under temperate climate and adds a new quantification of hydrosedimentary fluxes in a surface and tile drained field separating surface drains and tile drains contributions. • High temporal resolution monitoring of surface and tile drain hydrosedimentary fluxes. • Suspended sediment yield was 0.49 t ha−1 and 1.08 t ha−1, in 2019–2020 and 2020–2021. • Tile drains contribute up to 11% of the suspended sediment load. [ABSTRACT FROM AUTHOR]

Ice flow can transfer variations in basal topography and basal slipperiness to the ice surface. Recent developments in this theory have made it possible to conduct numerical experiments to predict mesoscale surface topographical undulations and surface relief on an ice sheet-scale. Focussing here on the contemporary Greenland Ice Sheet (GrIS), we demonstrate that the theory can be used to predict the surface relief of the ice sheet from bed topography, ice thickness and basal slip ratio datasets. In certain regions of the GrIS our approach overestimates, while in others underestimates, the observed surface relief. The magnitude and spatial pattern of these mismatches correspond with the theory's limitations and known uncertainties in the bed topography and basal slip ratio datasets. Our prediction experiment establishes that the first-order control on GrIS surface relief is basal topography modulated by ice thickness, surface slope and basal slip ratio. Additional analyses show that the surface relief, which is controlled by the bed-to-surface transfer of basal topography, preconditions the large scale spatial structure of surface drainage, with other factors such as surface runoff modulating the actual drainage system through influencing the temporal evolution of meltwater features. It follows that the spatial structure of surface drainage depends strongly on the transfer of basal topography to the ice surface. These findings represent an important step toward investigating and understanding the net long-term (>102 years) effect of surface drainage on ice sheet mass balance and dynamics during deglaciation events.

Forage production in Cuba is of paramount importance for the consumption of tropical livestock, the areas dedicated to obtaining this food are generally located in soils prone to waterlogging, that caused a decrease in forages yields, particularly in the rainy season. In areas of Niña Bonita enterprise, in the municipality of Bauta, (Artemisa's province); was selected a 200 ha forage field, in order to carry out an study of drainage needs and a proposal of possible solutions and economic feasibility of drainage solutions visualizes. Rainfall were studied in the period from 1994 to 2014, and surface runoff was calculates using curve number (CN) method. The design rainfall was 176.11 mm, which produce a maximum runoff of 160.9 mm; when using a 72-hour drain time, a drainage coefficient of 5.96 L/s ha was obtained, which produces a total design flow of 484 l/S. In attention to the above the proposed drainage system consists of a collector channel parallel to the main vial, which, due to the changes in slope in the ground was divided into four sections; Having sufficient capacity to evacuate the 484 L/s of the calculated flow rate. In all cases, channels have been calculated to exceed the flow to be evacuated by 27%, it would guarantee their maintenance-free operation in at least two years. [ABSTRACT FROM AUTHOR]

The vast majority of the landslides in Hong Kong are triggered by rainfall. Surface drainage commonly provided on man-made slopes aims to prevent surface erosion and reduce infiltration. It plays an important role to avert slope instability. However, inadequate management of surface drainage could hamper its efficiency and often results in uncontrolled surface water flow contributory to landsliding. This paper provides insights on the importance of slope surface drainage management under the dense urban settings in Hong Kong from the landslide perspective. Selected landslides involving inadequately managed surface drainage are presented to highlight the key lessons learnt and areas deserving attention on various drainage aspects, including the design and detailing. It is noteworthy that inadequate surface drainage maintenance could exacerbate and lead to sizeable landslides even on engineered slopes. A review of landslide records over the years suggests that some landslides could have been averted had there been proper surface drainage maintenance. [ABSTRACT FROM AUTHOR]

To evaluate the performances of a controlled drainage system in optimizing water use and reducing nutrient losses from agricultural fields, an experimental facility was set up in north-eastern Italy in 1996. Water table management was tested in combination with surface (open ditches) and subsurface (pipe) drainage systems. Data were collected from 2007 to 2013 on: water table depth, drained volumes, nitrogen and phosphorus concentrations in groundwater and in drainage water. Nitrogen in groundwater showed higher concentrations when controlled drainage was combined with open ditches system, with a median of 13.43 mg L −1 for NO 3 -N and 18.68 mg L −1 for total N. Drainage water showed an opposite trend: subsurface pipes with free drainage provided highest concentrations due to extensive leaching (a median of 20.7 mg L −1 for NO 3 -N and 24.0 mg L −1 for total N). Phosphorus concentrations showed notable differences in drainage water, with higher values in the controlled drainage – open ditches system due to surface runoff (a median of 0.190 mg L −1 for PO 4 -P and 0.536 mg L −1 for total P). In general, the most hazardous period for surface water pollution was autumn-winter, due to rainy weather and fertilizer application on bare soil. Overall, water table management reduced total water discharge by 81% compared to free drainage. On average, with controlled drainage annual nitrogen losses were lowered by 92% (from 29 to 2 kg NO 3 -N ha −1 ) and annual phosphorus losses by 65% (from 0.14 to 0.05 kg PO- 4 P ha −1 ). Free drainage with subsurface pipe was the worst combination from the environmental point of view: annual nitrogen and phosphorus losses were 46 kg NO 3 -N ha −1 and 0.10 kg PO 4 -P ha −1 respectively. Water table management clearly proved to be a reliable tool to improve both water usage and quality. [ABSTRACT FROM AUTHOR]

Pluvial flooding in urban areas may derive from the limited or temporarily reduced efficiency of surface drainage, even when the underlying storm sewers are properly designed. This study focuses on the impact of uncertainties in the operational condition of the surface drainage system on pluvial flood hazard. The flood propagation model FLURB-2D is implemented on a selected study area in the town of Genoa (Italy). Synthetic hyetographs based on the Chicago and bivariate copula methods with suitable return periods are used as input. While simulating the design rainfall, inlet operational conditions are varied stochastically using a Monte Carlo approach. Results confirm that microtopography has the potential to impact the efficiency of surface drainage and consequently to produce local flooding, with significant water depth in zones of flow concentration. Furthermore, the derived inundation maps allow the highlighting of areas with insufficient design of the surface drainage system (inlet size and positioning). [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Agricultural drainage increases hydrological connectivity between fields and receiving environments. Tile drains and drainage ditches are the main drainage types studied at the field scale. They can be associated with temporary surface drains to improve the removal of surface water. Combining surface drains with tile drains is likely to modify surface runoff and soil water dynamics. The behaviour of tile-drained fields has been studied at the event scale, but few studies have been conducted over a full hydrological year, and no studies have quantified water volumes in a field combining surface and tile drainage. So quantifications of water partition between surface drainage, tile drainage and soil water are needed to understand the hydrological behaviour of a field combining surface and tile drains. Moreover, at the event scale, few studies showed macropores can contribute to tile drain runoff but the partition between preferential flow and matrix flow is still unclear. It needs to be study depending on several parameters as soil type, soil water content or agricultural practice for a better understanding. In this study, high temporal resolution quantification of surface runoff and tile drainage was conducted for two full hydrological years to study hydrological functioning of the field using the water balance for a drained field. Soil water pathways were studied under dry and saturated soil conditions, tracing water by measuring stable isotope (18O and 2H) concentrations in rainwater, soil water, and surface and tile runoff. Runoff quantification showed that surface drainage and tile drainage respectively transferred 44% and 20% of annual effective rainfall. However, water balance showed that, at the annual scale, 65% of infiltrating water was not captured by tile drains. At the event scale, water tracing showed a season variation in macropores contribution depending on soil hydric state. Under dry conditions, rainwater was directly transferred to tile drains, likely through macropores. On saturated soil, pre-event soil water content provided most of the water flowing out from the tile drain, but rainfall can contribute up to 25% of the water flowing out from the tile drains. Combining water balance and water trancing allowed to propose a conceptual model for surface and tile drainage hydrological functioning at the event scale. • High temporal resolution monitoring of surface and tile drain runoffs. • Two years water balance of a field combining surface and tile drains. • Around 65% of infiltrating water is not intercepted by tile drains. • Macropore contribution to tile drain flow depends on soil hydric state. [ABSTRACT FROM AUTHOR]

The results of stationary studies of swampy southern taiga forests in Yaroslavl oblast are presented. Estimates of changes in the thickness of peat horizon in peat podzolic gley soils (Folic Albeluvisols) of forests subjected to clearcutting and further intensive forest management in the past 30 years are given. The mean annual precipitation in these three decades has been 116 mm higher than that during the preceding three decades, which has led to a progressive swamping of spruce stands on heavy loamy soils within virtually flat (with slopes up to 0.0035) surfaces and an increase in the organic matter storage in the peat soil horizon with the mean annual rate of 22-68 g/m. On more pronounced slopes (0.0050), no swamping of spruce and pine stands growing on sandy soils has taken place. Surface drainage of swampy forests through the network of shallow ditches has led to an increase in the productivity of forests; in most cases, the pool of organic matter in the peat horizon has been decreasing with the mean annual rate of 32-46 g/m. This attests to the reversible character of swamping in dependence on climatic fluctuations and forestry measures. Changes in the carbon pool of swampy soils during short (several years) excessively wet or excessively dry periods may be significantly higher than the average values for 30 years in different types of forests. This allows us to consider swampy forests as the source of significant errors in the estimates of the current contribution of biota to the carbon cycle, because their role (as well as the role of other forests) is assessed without taking into account considerable short-term fluctuations in the carbon pool of their soils. [ABSTRACT FROM AUTHOR]

The company AGROFORESTAL UUMBAL CHIAPAS, SAPI DE CV (UUMBAL) asked the Mexican Institute of Water Technology (IMTA) to carry out an investigation on the variation of the water table and the influence of the tides in the Polvoxal Ranch, located in theState of Campeche, Mexico. For this research study, the following actions were carried out: i) eleven observation wells and three wells (X, Y,Z) were installed and georeferenced, the depth of the water table wasmeasured daily, Which show that the water table reaches the soil surface at critical times (Hurricane Boris, June 7, 2014), but descends rapidly when it stops raining; The isohypsas planes indicate that the directionof the flow is towards the Candelaria river. The most critical part is close to the mangroves of the Natural Protected Area and not in the areawhere it will be implanted, that with a good drainage would not have anyproblem, ii) with respect to the tides, these were measured daily at 06: 00 and 18:00 hours, and when related to the water table, show that there is no marine intrusion, iii) the oil palm can accept a maximum of 72 hours with high humidity, if it persists it is necessary to build both main and Parcel. As for the main surface drainage will consist in part give him maintenance of the streams that are in the project area and construct interceptor drains. [ABSTRACT FROM AUTHOR]

Various indexes should be considered when developing a suitable irrigation and drainage scheme for crops. Our study chosen tomato as plant material and conducted a field experiment under saline soils. Nine treatments distinguished by different irrigation quotas and different drain ditch depths were used for the optimization of irrigation-drainage scheme. A flooding irrigation treatment with no surface drainage was adopted as control. The system of evaluation indexes was established in comprehensive consideration of the electrical conductivity and nutrient of soil, and the water use efficiency, nitrogen use efficiency, quality and marketable yield of tomato. Moreover, the multi-index analysis and projection pursuit (PP) model were used to evaluate the irrigation-drainage schemes according to the observed values of these six evaluation indexes. Results showed that different irrigationdrainage treatments decreased the electrical conductivity in plough layer by 24.6-51.3%, and increased the tomato water use efficiency and nitrogen use efficiency by 0.3-24.2% and 20.3-96.0%, respectively. The tomato marketable yield was increased by 14.4-31.3% with the irrigation-drainage treatments when compared to the control. As analyzed by the PP model, I3D1 (300 m3 hm-2 of irrigation quota combined with 10 cm of ditch depth) was the treatment that possessed best comprehensive benefits due to the highest projection value of 1.6724 thus was recommended by this study as the optimal irrigation-drainage scheme. [ABSTRACT FROM AUTHOR]

This study aims to present a methodology for the design of a surface drainage system for dry docks in shipyards, taking into account the rainfall intensity at the site, the damping capacity of the hydraulic structures (drainage channels) and the pumping capacity of the pumping system. A case study of a dry dock owned by Estaleiro Rio Grande, located at the state of Rio Grande do Sul, is presented. The results obtained indicate alternatives for channel and submersible pump sizing. These pumps would be used to control the dry dock flooding after an intense rainfall event. [ABSTRACT FROM AUTHOR]

Over past decades, China has changed the manner in which coal mine methane (CMM) was treated: from mitigating its dangers as a mining hazard to developing its potential as an unconventional gas resource. CMM is rich in China coal seams. These coal seams normally have three distinct characteristics: high pressure, strong adsorption and low permeability. These characteristics require novel extraction and utilization technologies. This paper presented a comprehensive review of how these technologies evolve with time from underground extraction to surface drainage to combined surface-underground approach. Major conclusions include: (1) CMM is mainly drained through underground extraction technologies. In order to improve the drainage efficiency, these technologies usually combine with mining-induced stress relief or other active stimulation techniques and modern borehole sealing techniques; (2) Several innovative surface CMM extraction technologies have been proved as effective for Chinese CMM formation conditions, such as gob surface well extraction, stress-relieved seams surface well extraction, multi-branch horizontal directional surface well extraction, and multipurpose surface well extraction; (3) A combined surface-underground approach has been applied to Huainan and Jincheng coal mines. These applications represent the new development trend of CMM extraction and control in China; and (4) Apart from the CMM extraction technologies, utilization technologies also achieved significant progresses in China. The electricity generation and safe transportation technologies of low-concentration gas have also been developed to improve the gas utilization rate and guarantee the safe long distance and large flow transportation of low-concentration gas in China. The implementation of CMM extraction and utilization technologies has led to a large increase of coal production, gas extraction and utilization, and a significant reduction of fatality. [ABSTRACT FROM AUTHOR]

Copyright of Irrigation & Drainage is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, a general information about surface drainage of urban streets is given and it is investigated that if the storm water drainage inlets of the road between Yakutiye municipality and Havuzbaşı are sufficient or not. The selected highway is divided into 7 sections, calculations are done for each section and storm water inlets are placed into the road. Calculations for section 1 are showed. In other parts storm water inlets are found by using the same calculation process "as in the section 1" is done. After using the Rational and Manning formulas to calculate the amount of water falling on the road and water carrying capacity of the gutters, the distance between the grate rain water inlets of the type of grates which are used by the General Directorate of Highways is found. Using different size of grate inlets for different roads will not be economical and also producing different size of grate inlets will be hard so the type of grates which belong to General Directorate of Highways are used. The storm water inlets that found after drainage calculations are compared with storm water inlets of existing road and it is seen that storm water inlets of selected road are not enough and the placed shapes of them are wrong. [ABSTRACT FROM AUTHOR]

Surface drainage at the neighborhood and street scales plays an important role in conveying stormwater and mitigating urban flooding. Surface drainage at the local scale is often ignored due to the lack of up-to-date fine-scale topographical information. This paper addresses this issue by providing a novel method for evaluating surface drainage at the neighborhood and street scales based on mobile lidar (light detection and ranging) measurements. The developed method derives topographical properties and runoff accumulation by applying a semantic segmentation (SS) model (a computer vision technique) and a flow direction model (a hydrology technique) to lidar data. Fifty lidar images representing 50 street blocks were used to train, validate, and test the SS model. Based on the test dataset, the SS model has 80.3% IoU and 88.5% accuracy. The results suggest that the proposed method can effectively evaluate surface drainage conditions at both the neighborhood and street scales and identify problematic low points that could be susceptible to water ponding. Municipalities and property owners can use this information to take targeted corrective maintenance actions. • The study developed a method that integrates computer vision and flow direction model to assess surface drainage condition. • This study applied the developed method to 50 street blocks in a neighborhood in Houston, Texas. • The developed model can identify key drainage and land features within a street block with an accuracy of 88.5%. • The results can show problematic areas susceptible to water ponding and inform drainage maintenance decisions. [ABSTRACT FROM AUTHOR]

In this paper, a novel procedure is presented and demonstrated for the optimal design of rural drainage networks, based on the coupling of a genetic algorithm with suitable hydrologic and hydraulic models. The models, which allow the evaluation of water depth and discharge through the network, differ for the levels of simplification introduced into the representation of physical phenomena (rainfall-runoff transformation and flood wave propagation through channels). Their applications are shown and the use of oversimplified approaches is discussed: although very popular in practice, they can adversely affect the characteristics of the optimal network. [ABSTRACT FROM AUTHOR]

Focusing on triangular gutters with one vertical side, four issues pertaining to the design of street gutters are addressed: (1) the proper coefficient in Manning's formula for uniform flow and friction loss in gutters; (2) adjustment of frictional resistance for spatial inflow; (3) whether uniform flow occurs in gutters with spatially increasing flow; and (4) interaction with inlets. The first of these issues is addressed by considering historical and modern information to recommend the best of two different equations that have been put forward for determining the uniform flow capacity and friction loss in gutters. The second concern is addressed for subcritical and supercritical gutter flow, for which practical, generalized numerical solutions are derived. The range of parameters for which uniform flow provides an adequate approximation is demonstrated theoretically and by example. Among the important conclusions is that the common practice of using Manning's equation alone for such problems is not always adequate. Practical recommendations are made to address the third issue. The fourth concern is addressed by building on the material thus presented and literature information. This work has important implications for more generally regarding the characteristics and relationships for subcritical and supercritical flow in open channels. [ABSTRACT FROM AUTHOR]

Urban drainage systems have two different drainage layers, one superficial and another underground, that are connected through drain inlets and manholes. Specifically, a collection system is formed by inlets distributed throughout a basin, with the function of collecting and directing the surface runoff into sewers. Generally, the hydraulic characterisation of the inlet system considers the grates in an ideal state, free of dirt and debris obstructions, although often this is not the case. In these cases, clogging effects should be considered as a reduction in terms of hydraulic efficiency. The aim of this paper is to present a methodology to determine, quantitatively, the hydraulic efficiency reduction of partially clogged grated inlets. With this aim, clogging patterns for the most common grated inlets operating in Barcelona (Spain) were defined and experimental tests at real scale were carried out in order to determine the hydraulic efficiency reduction due to clogging phenomena. [ABSTRACT FROM AUTHOR]

North-central Iowa is an agriculturally intensive area comprising the southeastern portion of the Prairie Pothole Region, a landscape containing a high density of enclosed topographical depressions. Artificial drainage practices have been implemented throughout the area to facilitate agricultural production. Vertical surface drains are utilized to drain the topographical depressions that accumulate water. This study focuses on the hydrology of a drained topographical depression located in a 39.5 ha agricultural field. To assess the hydrology of the drained depression, a water balance was constructed for 11 ponding events during the 2008 growing season. Continuous pond and groundwater level data were obtained with pressure transducers. Flows into the vertical surface drain were calculated based on pond depth. Precipitation inflows and evaporative outflows of the ponds were calculated using climatic data. Groundwater levels were used to assess groundwater--pond interactions. Results of the water balances show distinct differences between the inflows to and outflows from the depression based on antecedent conditions. In wet conditions, groundwater inflow sustained the ponds. The ponds receded only after the groundwater level declined to below the land surface. In drier conditions, groundwater was not a source of water to the depression. During these drier conditions, infiltration comprised 30% of the outflows from the depression during declining pond stages. Over the entire study period, the surface drain, delivering water to the stream, was the largest outflow from the pond, accounting for 97% of the outflow, while evapotranspiration was just 2%. Precipitation onto the pond surface proved to be a minor component, accounting for 4% of the total inflows. [ABSTRACT FROM AUTHOR]

Focusing on triangular gutters with one vertical side, four issues pertaining to the design of street gutters are addressed: (1) the proper coefficient in Manning's formula for uniform flow and friction loss in gutters; (2) adjustment of frictional resistance for spatial inflow; (3) whether uniform flow occurs in gutters with spatially increasing flow; and (4) interaction with inlets. The first of these issues is addressed by considering historical and modern information to recommend the best of two different equations that have been put forward for determining the uniform flow capacity and friction loss in gutters. The second concern is addressed for subcritical and supercritical gutter flow, for which practical, generalized numerical solutions are derived. The range of parameters for which uniform flow provides an adequate approximation is demonstrated theoretically and by example. Among the important conclusions is that the common practice of using Manning's equation alone for such problems is not always adequate. Practical recommendations are made to address the third issue. The fourth concern is addressed by building on the material thus presented and literature information. This work has important implications for more generally regarding the characteristics and relationships for subcritical and supercritical flow in open channels. [ABSTRACT FROM AUTHOR]

In this paper, a novel procedure is presented and demonstrated for the optimal design of rural drainage networks, based on the coupling of a genetic algorithm with suitable hydrologic and hydraulic models. The models, which allow the evaluation of water depth and discharge through the network, differ for the levels of simplification introduced into the representation of physical phenomena (rainfall-runoff transformation and flood wave propagation through channels). Their applications are shown and the use of oversimplified approaches is discussed: although very popular in practice, they can adversely affect the characteristics of the optimal network. [ABSTRACT FROM AUTHOR]

The present paper presents a generalized solution for the hydrologic and hydraulic design of small to medium-sized storm-water pumping stations. The solution enables determination of pump capacity and the corresponding storage capacity. The benefits of the solution include: (1) the ability to consider the effects of storm duration rather than the fixed hydrology assumed in other methods; (2) a simpler and more intuitive design procedure than other available methods; and (3) enabling the calculation of storage requirements independent of the geometry of the wet well and any inundated upstream area. The relation of the method presented herein to several other available methods is presented and the other methods critiqued conceptually and by example. The example is favorably tested using commercial software, and the constant-pumped-discharge assumption of the example is further tested using that software for an actual pump discharge-total dynamic head and system flow-head relationship. Extension of the methods presented in this paper to more complex situations is discussed. The importance of considering different storm durations is emphasized. [ABSTRACT FROM AUTHOR]

This paper presents the technical solutions. takes to the degraded area's improvements from the Timiş County perimeter. The actual state of the agrarian lands is determinate by the vulnerability of their site, but also, by the management way, because of it isn't assure the improvement solutions that are necessary and isn't used the correctly agricultural systems or the culture technology that are properly. The negative influences that are caused by these facts, according with the risk natural factors, amplificatory negative processes generated. The degradation of the lands that are located into the low plain from Timiş County is determinate by the humidity excess. The multitude of the drainage systems solved this problem, but not completely. The flooding from 2005 affects a surface of hundreds or thousands kilometer. The agrarian lands lost their productive capacity because of their degraded or pollutions. All these areas were formed into the territorial agrarian fond ameliorative perimeter, where the land reclamation works is necessary. Another cause of the degradation processes is the grass land thickness that is lower, so the water stagnate tendenby is higher. From these aspects, a soil levigation occurs and their humus contents decrease, also the degradation process increase. [ABSTRACT FROM AUTHOR]

Within three decades of European-descended settlers arriving in Iowa, much of the land cover across the state was transformed from prairie and forest to farmland, patches of forest, and urbanized areas. Between 1832 and 1859, the General Land Office surveyed the state of Iowa to aid in the disbursement of land. In 1875, an illustrated atlas of the State of Iowa was published. Using these two data resources for classifying land cover, the hydrologic impact of the land cover change resulting from the first three decades of settlement is presented in terms of the effect on the area-weighted average curve number, a term commonly used to predict runoff from rainstorms. In the four watersheds studied, the area-weighted average curve number increased by a mean of 16.4 from 61.4 to 77.8 with the greatest magnitude of change occurring in the two western Iowa watersheds as opposed to the two more heavily forested eastern Iowa watersheds. [ABSTRACT FROM AUTHOR]

Abstract: In Ethiopia vertisols cover about 10% of the total land area and is the fourth most important soil used for crop production, accounting for nearly 23% of the total arable land used for crop production. More than half of the vertisols are found in the Central Highlands of Ethiopia, with an altitude of more than 1500m above mean sea level. The unique physical and chemical properties of these soils and the high rainfall during the main cropping season create severe surface waterlogging problems which hinder crop production activities. Severe surface waterlogging affects the growth of plants by impeding nutrient uptake and creating oxygen deficiency around the root zone. To address this crop production problem, three surface water drainage methods, namely broad bed and furrow (BBF), ditch, and flat (traditional) methods were evaluated using the water balance of the plant root zone and wheat as a test crop. The experiment was conducted at the Ginchi Research Station in the central highlands of Ethiopia over two consecutive seasons (2000 and 2001). The results showed that both the BBF and the ditch drainage methods gave about 33% and 22% more grain yield than the flat treatment, respectively. However, there were no significant differences between BBF and ditch for both grain and biomass yield during both experimental seasons. During both seasons the total water balance (ΔW r ) at the root zone especially, in the months of June, July and August on all the treatments was higher than the crop water requirement (ETc) and showed no significant difference between the treatments. Thus, the results of this study indicated that the soil water in the root zone was not significantly altered by surface drainage systems and therefore implies the need of further improvement of the different surface drainage methods regarding improving the waterlogging condition and hence the productivity of the vertisols in the Central Highlands of Ethiopia. [Copyright &y& Elsevier]

A particularly useful generalized numerical solution for detention basin design is presented and sets the stage for practical applications for roof detention and the rationale and use of such a solution for detention basin design more generally. The generalized numerical solution provides results that can be applied to practical problems in certain cases and demonstrates the general importance of storm duration. The method utilizes a trapezoidal inflow hydrograph, which includes the important effect of storm duration based on the modified rational method. Convenient charts are presented to display the relationship between the variables. The derivation provides the basis for specializing the method to provide generalized curves applicable to storage detention on roofs. Although the results presented herein are more generalized than those presented by other writers, certain other methods are shown to compare favorably for special cases. An added perspective is provided on some of those other methods. Soil Conservation Service TR-55 curves are included in the comparisons, which demonstrates their limitations. An example demonstrates application of the generalized curves. [ABSTRACT FROM AUTHOR]

Assessment of soil loss/deposition from quarter-drains (drainage ditches perpendicular to furrows) at specific locations or determining sediment transport within ditch systems following a rainfall event is difficult and time consuming. Automatic samplers are stationary and usually located at the end of plots to assess total sediment loss from a whole area. However, to quantify changes to cross-sectional areas at specific points within a ditch system, a portable measuring tool is required. To precisely assess soil erosion along the length of a quarter-drain, a portable device was designed and tested under typical field conditions. One person can effectively operate the device and because of its low cost, it is ideal for cases where budget constraints exist. The tool can measure depths up to 500 mm and easily be modified for usage with large ditches. The device was successfully employed in the spring and summer of 2003 and 2004 where it was utilized after rainfall events to assess soil erosion/deposition from quarter-drains on sugarcane fields in southern Louisiana. [ABSTRACT FROM AUTHOR]

This paper describes the essential contents of research at a recently completed subsurface pipe drainage project located in the Khushab district of Pakistan. The paper explores the need and decision by Government of Pakistan to install a Sub Surface Pipe Drainage Project near Khushab where an old Surface Drainage System was already installed by the Provincial Irrigation and Power Department, Government of Punjab, Pakistan, since 1960. The new Sub Surface Pipe Drainage Project’s planning and executing agency M/S Euro-Consultant used existing Surface Drains with remodeling for to carry the additional drainage effluent of newly constructed sump pumps of the pipe drainage system connected to the old drains by means of small outfall drains. Until now the new system is working well in lowering the water table as well as increasing the agro-socio-economic status of the local population. [ABSTRACT FROM AUTHOR]

The objective of this study was twofold: (1) quantify the benefits of a specially designed geocomposite membrane [a low modulus polyvinyl chloride (PVC) layer sandwiched between two nonwoven geotextiles] to act as a moisture barrier in flexible pavement systems; and (2) quantitatively measure the moisture content of unbound granular materials nondestructively. The geocomposite membrane was installed over half the length of a pavement test section at the Virginia Smart Road, while the other half of the test section consisted of the same design without the interlayer system. An air-coupled ground penetrating radar (GPR) system with 1 GHz center frequency was used to monitor and detect the presence of moisture within the pavement system over different periods of time corresponding to different levels of water accumulation. Results of GPR data analysis indicated that the use of the geocomposite membrane reduced water infiltration to the aggregate base layer by as much as 30% when measurements were performed after rain. It was also found that the moisture content underneath the interlayer was almost constant and therefore independent of the amount of rainwater, which is the primary source of moisture in pavement systems that have a low water table. The impact of moisture in the granular layers was investigated using the results of a deflection monitoring program. The results indicate that the area with the geocomposite membrane always showed less deflection than the area without the interlayer. The study recommends that any pavement drainage layer must be backed by an impermeable interface, given that the water table is low. [ABSTRACT FROM AUTHOR]