Highly modified channels drain extensive portions of productive agricultural land in the U.S.A. I... more Highly modified channels drain extensive portions of productive agricultural land in the U.S.A. In many of these areas, most natural channels have been deepened and straightened to facilitate the flow of water from agricultural subsurface drainage outlets and to maximize conveyance. Work done periodically to maintain the drainage function typically includes removal of woody vegetation and deposited sediment. Ancillary work includes stabilizing bank slope failures and toe scour. Ditch form is a result of not only construction and maintenance but also, to verifying degrees, due to fluvial (flowing water) processes. The purpose of this project was to demonstrate through applied research and outreach education an alternative drainage channel form approach that incorporates naturalized fluvial features to enhance stream integrity and maintain or improve drainage capacity. The objectives of this project, addressed below, focused on understanding the conditions that favor such evolution an...
This invention relates to a balloon dilatation catheter. The balloon dilatation catheter comprise... more This invention relates to a balloon dilatation catheter. The balloon dilatation catheter comprises a first, inflation lumen extending therethrough and having distal and proximal ends, the distal end of the first lumen opening into and being in fluid communication with the interior of an inflatable dilatation balloon having distal and proximal ends, and a second lumen extending coextensively with and exterior to the dilatation balloon.
Water flow through point-of-use porous ceramic water treatment fil- ters have been theoretically ... more Water flow through point-of-use porous ceramic water treatment fil- ters have been theoretically analyzed in this technical paper. Filters tested were manufactured by combining low cost materials namely, clay and sawdust. Three filters with distinct volume fractions of clay to sawdust (75:25, 65:35 and 50:50) were tested. Sintered clay filters casted in frustum shapes were structurally char- acterized using mercury intrusion porosimetry. A linear increase in porosity with volume fraction of sawdust was observed. Flow experiments were carried out at constant room temperature and pressure. Potable tap water was used in these studies. Flows through filters occurring with drop in the head of water under gravity were statistically analyzed. Discharges through the filters were predicted with respect to independent variables of time for cumulative discharge and volume fraction of sawdust used for manufacturing the filters. The experimental data analysis predicts a multiplicative influence ...
Abstract Subsurface (tile) drainage is a necessary practice for economic crop production in humid... more Abstract Subsurface (tile) drainage is a necessary practice for economic crop production in humid, poorly drained regions of the world. Drainage water management (DWM), also known as controlled drainage, is among the suite of practices designed to mitigate water quality issues associated with subsurface drainage. Studies evaluating DWM generally include field experiments or simulation models to estimate water quality impacts. Combining field studies with model simulations can provide a more comprehensive assessment. Furthermore, using multiple approaches can provide a range of effectiveness rather than a single estimate, which can help define the uncertainty associated with DWM effectiveness. The goal of this study was to demonstrate the variability in estimated DWM effectiveness using 10 years of measured data and a calibrated hydrologic model. The study field, located in central Ohio, was under a free drainage (FD) mode from 2005 through 2008, and under DWM from 2009 through 2014. We used three approaches to compare discharge and nitrate concentrations and loads: before-and-after, paired-field, and DRAINMOD-NII simulated scenarios. Based on the three evaluation approaches, DWM increased surface runoff by 50% (∼13 mm), reduced annual drainage discharge between 8 and 23% (∼19 to 69 mm), annual mean NO3-N concentrations between −1 and 2.5%, and NO3-N loads between 9 and 25% (∼2.8 to 10.3 kg ha−1 yr−1). DWM also reduced the frequency of drainage discharge, and increased magnitudes of surface runoff, evapotranspiration, and seepage losses. The true magnitude of DWM effectiveness remains somewhat uncertain, especially in fields prone to seepage and runoff losses. However, using a combined assessment approach can help address the uncertainty associated with estimated DWM effectiveness at watershed and regional scales.
Abstract Although many sensitivity analyses using the soil and water assessment tool (SWAT) in a ... more Abstract Although many sensitivity analyses using the soil and water assessment tool (SWAT) in a complex watershed have been conducted, little attention has been paid to the application potential of the model in unique plots. In addition, sensitivity analysis of percolation and evapotranspiration with SWAT has seldom been undertaken. In this study, SWAT99.2 was calibrated to simulate water balance components for unique plots in Southern China from 2000 to 2001, which included surface runoff, percolation, and evapotranspiration. Twenty-one parameters classified into four categories, including meteorological conditions, topographical characteristics, soil properties, and vegetation attributes, were used for sensitivity analysis through one-at-a-time (OAT) sampling to identify the factor that contributed most to the variance in water balance components. The results were shown to be different for different plots, with parameter sensitivity indices and ranks varying for different water balance components. Water balance components in the broad-leaved forest and natural grass plots were most sensitive to meteorological conditions, less sensitive to vegetation attributes and soil properties, and least sensitive to topographical characteristics. Compared to those in the natural grass plot, water balance components in the broad-leaved forest plot demonstrated higher sensitivity to the maximum stomatal conductance (GSI) and maximum leaf area index (BLAI).
Abstract Subirrigation is employed to supply water to crop root zones via subsurface drainage sys... more Abstract Subirrigation is employed to supply water to crop root zones via subsurface drainage systems, which are typically installed for the purpose of excess soil water removal. Crop yield increases due to subirrigation have been demonstrated in numerous studies, but there is limited information regarding yield under future climate conditions when growing season conditions are expected to be drier in the U.S. Corn Belt. DRAINMOD was calibrated and validated for three locations with different soil series in northwest Ohio and used to investigate maize relative yield differences between subirrigation and free subsurface drainage for historic (1984–2013) and future (2041–2070) climate conditions. For historic conditions, the mean maize relative yield increased by 27% with subirrigation on the Nappanee loam soil, but had minimal effect on the Paulding clay and Hoytville silty clay soils. Maize relative yield under free subsurface drainage is predicted to decrease in the future, causing the relative yield difference between free subsurface drainage and subirrigation practices to nearly double from 9% to 16% between the historic and future periods. Consequently, the subirrigation practice can potentially mitigate adverse future climate change impacts on maize yield in northwest Ohio.
Drought during maize (Zea mays L.) growing season in the US Midwest can be mitigated using draina... more Drought during maize (Zea mays L.) growing season in the US Midwest can be mitigated using drainage and runoff water recycling through subirrigation. Limited information regarding subirrigation timing and intensity hinder its promotion across the region. Seven water table management strategies were simulated using DRAINMOD calibrated for three locations with different soil series in northwest Ohio, under 1984 to 2013 climate conditions, and were compared based on annual relative yield, subirrigation water volume, relative water discharge, and management intensity. Annual relative yields ranged between 63.1% and 64.4% at the Defiance site and were not significantly different between the water table management strategies. Under subirrigation, relative yields ranged from 87.3% to 93.2% and 80.4% to 90.8%, respectively, at the Fulton and Van Wert sites and were significantly larger than under free subsurface drainage. Annual subirrigation water volumes were significantly lower under continuous subirrigation from V3 stage at all three locations. Subirrigation water volumes at the Fulton and Van Wert sites were particularly lower with continuous subirrigation starting at V9. Relative water discharges were similar across all water table management strategies at the Defiance site and larger under free subsurface drainage at the Fulton and Van Wert sites. Free subsurface drainage was the most appropriate option for the Defiance site in terms of water table management because subirrigation did not improve the relative yield but consumed water (and, consequently, energy for pumping). For the Fulton and Van Wert sites, continuously subirrigating from V9, with the control weir set at 61 cm below ground surface and raised to 35 cm below ground surface at tasseling improved the relative yield while using less subirrigation water volumes and generating no greater relative water discharge (hence no greater dissolved nutrient loads) than the other subirrigation options. This strategy potentially reduces labor costs at locations where subirrigation is appropriate, enhancing the economic viability of subirrigation, and is the most applicable strategy to other major maize-growing areas in the Midwest. Results indicate water table management and subirrigation will benefit Midwestern maize production under projected climates, which suggests increased potential for water stress in most growing seasons by 2041 to 2070. Future studies, extending this approach to more diverse regions, accompanied by more in-depth economic assessments, are needed to further evaluate potential benefits of subirrigation.
Drained lands, which include some of the most productive lands in the world, can experience both ... more Drained lands, which include some of the most productive lands in the world, can experience both water excess and water deficit within a year. Storing drained water within the landscape could increase the sustainability of water for agriculture, particularly as intense rainfall and prolonged summer drought continue to increase under future climate change. A team of researchers and extension specialists from nine states are currently working towards a vision of transforming the process of designing and implementing agricultural drainage to include storage through the use of controlled drainage, saturated buffers, and drainage water recycling (i.e. capture, storage, and reuse). Field research data from experimental drainage sites from across the U.S. Corn Belt have been brought together in a database to support synthesis and modeling to determine economic and environmental impacts of drainage water storage. Results from this effort will extend the strategies and tools to agricultural producers, the drainage industry, watershed managers, agencies, and policy makers, and educate the next generation of engineers and scientists to design drainage systems that include water storage in the landscape.
Abstract This study investigates long-term trends of three different time scales including monthl... more Abstract This study investigates long-term trends of three different time scales including monthly, seasonally and annually at the upper Senegal River basin. Daily streamflows for the period 1961–2014 at Bafing Makana station were used and analyzed to conduct this research. The serial structural of the different time series (monthly, seasonal, and annual) were investigated in order to detect the presence of autocorrelation. Mann–Kendall test was applied to no autocorrelated series and the Modified Mann–Kendall test for the autocorrelated. Theil and Sen’s slope estimator test was used for finding the magnitude of change and Pettitt test was applied for detecting the most probable change year. Results exhibited a decreasing trend of the annual streamflow yet at the 5% significance level, streamflow series did not have any statistically significant trend for the whole period; however, integrating the different change years, decreasing trend is significant before the first breaking point (1976) and increasing trend is significant from first breaking point to the second change point (1993). For the monthly series, all months exhibit a non-significant decreasing trend except for the month of June. The seasonal series show a decreasing trend which a significant at MAMJ season. Change years were varying accordantly to the scale.
Based on the hydrological characteristics of a rice-based irrigation system in Southern China, th... more Based on the hydrological characteristics of a rice-based irrigation system in Southern China, the SWAT (Soil and Water Assessment Tool) model was modified in order to develop the Rice Irrigation System-Soil and Water Assessment Tool (RIS-SWAT). The irrigation water movement, water balance module, and rice yield calculations of the paddy field were improved within the SWAT model. In addition, the seepage of the irrigation canal and the pond’s effect on the irrigation modules were added to the RIS-SWAT. The impact of water management on the water cycle of the small watershed irrigation system (SWIS) was evaluated by conducting a scenario analysis with RIS-SWAT. The results indicated that an increase in the maximum water ponding depth of a paddy field could decrease irrigation water and rainfall loss. The canal water supply was reduced by 20%, resulting in an increase in irrigation water productivity without a reduction in the rice yield. The temporal and spatial distributions of the irrigation water in different subbasins did not significantly affect the water cycle within the SWIS. Furthermore, when the canal water supply was reduced by 20–40% and the pond water supply was increased, the rice yield was not affected. Thus, the water productivity of irrigation systems could be improved through the implementation of water management policies and practices that reduce field outflows and reuse the return flows captured by ponds.
ABSTRACT A workshop on Liquid Animal Manure Application on Drained Cropland: Preferential Flow Is... more ABSTRACT A workshop on Liquid Animal Manure Application on Drained Cropland: Preferential Flow Issues and Concerns (Columbus, Ohio; November, 2004) was conducted to prioritize extension and research activities in the Midwest. Seven extension priorities were identified: 1) Integrate simple manure application rules into the whole farm plan. 2) Required certification and continuing education credits for manure applicators. 3) Develop web-based fact sheets, video clips, and photos and use demonstrations to educate livestock producers on preferential flow issues. 4) Promote partnerships with agencies, industry, producers, and universities. 5) Develop educational programs for agency personnel on preferential flow issues related to manure application. 6) Develop computer programs to apply manure at a safe application rate. 7) Integrate manure management for liquid manure application into other programs. The top 17 research ideas were identified as well: 1) Pathogen transport and fate rated the highest. 2) Research soil types, water holding capacity, and preferential flow characteristics of soil. 3) Research manure characteristics. 4) Study application methods, application equipment and tillage methods. 5) Develop liquid manure testing methods, sensors, quick tests, and cost effectiveness of testing parameters. 6) Correlate factors from past manure violations cases into a national database. Other research priorities looked at developing alternative technology, adding value to the manure, research on precision application and variable rate technology, researching socio-economic data, water table control structures, water columns studies related to groundwater, storage/handling/application options, fate of liquid manure in agricultural subsurface drains, and developing parameters for manure characteristics.
9th International Drainage Symposium held jointly with CIGR and CSBE/SCGAB Proceedings, 13-16 June 2010, Québec City Convention Centre, Quebec City, Canada, 2010
Best practices for managing drainage water quality include the use of constructed wetlands for re... more Best practices for managing drainage water quality include the use of constructed wetlands for reducing nutrient loads. Nutrient reduction can be related to the hydraulic performance of a wetland. Hydraulic indexes used for quantifying the hydraulic efficiency of a wetland have more value when they can be used to predict treatment ability. This paper evaluates a number of common indexes describing hydraulic efficiency and relates them to the expected treatment derived from time dependant first order nutrient reductions. There is a need for a hydraulic index demonstrating strong correlation to pollutant reduction in order to identify the optimal wetland configuration for maximizing residence time. Such an index should quantify the effects of the various wetland parameters that influence the residence time distribution and supply the bounds for pollutant reduction.
This project calibrated and validated DRAINMOD 5.1 for prediction of nitrate concentrations in dr... more This project calibrated and validated DRAINMOD 5.1 for prediction of nitrate concentrations in drainage water from conventional and combined (controlled/subirrigated) drainage plots. Weather, soil, water quality and hydrology data collected at Piketon, Ohio during 1996 and 1997 were used. Results indicated that DRAINMOD 5.1 was able to predict daily water table heights (within 30 cm) for both conventional and combined drainage practices on Omulga silt loam soil. DRAINMOD 5.1predicted cumulative nitrate loads adequately for conventional drainage. Predictions for combined drainage consistently overestimated the nitrate loads, perhaps because the nitrogen cycle rate reactions were not modeled as a function of soil water content, or because the plant removal of N was too low.
Improved subsurface drainage continues to be a priority for agricultural producers in Ohio. Much ... more Improved subsurface drainage continues to be a priority for agricultural producers in Ohio. Much of the subsurface drain pipe is installed by specialty drainage contractors. Little research has been reported concerning the design practices and characteristics of subsurface drain installers. To develop background information for the Ohio Agricultural Water Management Guide, a mail survey was conducted to inventory contractor practices and estimate the extent of subsurface drainage installation from 1995-1997. Respondents were classified into two categories: those which installed subsurface drainage as their main business, and those for which it is a sideline business. Over 90% of the mainline firms had been in business for 11 years or more. Respondents reported the installation of over 10 000 km of drain pipe in 1997. Relatively few controlled drainage and sub-irrigation system installations were reported. Mainline firms installed about 90% of the total drain pipe installed. These firms rely on experience and self-generated topographic maps as their primary design aids. Many contractors reported the same drain depth and spacing for different soil series, suggesting that the soil type is not a main consideration in the installation. Further education and training may be needed to improve the design practices used by Ohio drainage contractors KEYWORDS. Agricultural drainage, drainage contractors, drain installation practices, drain spacing, drain depth.
Prediction of solar radiation is needed for a wide range of applications, such as for predicting ... more Prediction of solar radiation is needed for a wide range of applications, such as for predicting daily evapotranspiration. In our case, prediction of solar radiation is important for estimating power and energy needs. Predicting clear day radiation is a clear process, while predicting cloudy day radiation can be more complex. Having a capability to predict solar radiation for locations with no or very few data is an important need that we are trying to address. The Hargreaves and Samani model estimates for daily solar radiation in Wooster OH had good correlation between model prediction error and average solar radiation throughout year. To conduct a more appropriate assessment of results, we found that the RMSE should be calculated for a dry, a humid, and an average year, instead of calculating a general RMSE for the whole period. Choosing the model constant based on the difference between max and min daily temperature can improve predictions. Several modified versions of the Hargreaves and Samani model, such as the Allen selfcalibrating model, a lower-limit calibrating model based on relative humidity, and several combinations of these models, were used to evaluate using the models to produce probability distributions for solar data, and predicting statistical upper and lower limits of data in Ohio. The error analysis shows that the models with a combination of self-calibrating for the upper and lower solar radiation were more successful in predicting the expected solar limits.
ABSTRACT A denitrifying bioreactor is a system where a carbon substrate (commonly woodchips) is u... more ABSTRACT A denitrifying bioreactor is a system where a carbon substrate (commonly woodchips) is used to reduce nitrate concentration in water flow. For many years, water flow through woodchips has been assumed laminar without proper validation. The main objective of this study was to validate Darcy’s laminar flow assumption for woodchips. For this purpose, we conducted both constant head laboratory column experiments and field evaluation of a denitrification bed. Laboratory results revealed that Darcy’s law does not apply for the majority of the hydraulic gradients forcing flow through fresh and old woodchip media. However, Forchheimer’s equation adequately described the flow pattern using a quadratic equation. Statistical analysis showed that old woodchips (excavated from a denitrification bed) had significantly lower intrinsic permeability than fresh woodchips. We determined Forchheimer’s and Darcy’s in-situ coefficients, and used them to predict flow rate in a denitrification bed. Model evaluation statistics showed better flow rate prediction with Forchheimer’s than Darcy’s equation when compared with the measured flow rate. In conclusion, the linear flow assumption was inadequate for describing water flow through woodchips in a denitrification bed.
... Experimentation of New Resource Conserving Technology in Synergy with Micro-Turbo-based Canal... more ... Experimentation of New Resource Conserving Technology in Synergy with Micro-Turbo-based Canal Irrigation System Anand Krishnan Plappally, The OSU, Columbus, OH, USA Ravi Shankar Tripathi, RWC-CIMMYT, Delhi, India PMV Subbarao, PhD, Professor, IIT, Delhi, India ...
Highly modified channels drain extensive portions of productive agricultural land in the U.S.A. I... more Highly modified channels drain extensive portions of productive agricultural land in the U.S.A. In many of these areas, most natural channels have been deepened and straightened to facilitate the flow of water from agricultural subsurface drainage outlets and to maximize conveyance. Work done periodically to maintain the drainage function typically includes removal of woody vegetation and deposited sediment. Ancillary work includes stabilizing bank slope failures and toe scour. Ditch form is a result of not only construction and maintenance but also, to verifying degrees, due to fluvial (flowing water) processes. The purpose of this project was to demonstrate through applied research and outreach education an alternative drainage channel form approach that incorporates naturalized fluvial features to enhance stream integrity and maintain or improve drainage capacity. The objectives of this project, addressed below, focused on understanding the conditions that favor such evolution an...
This invention relates to a balloon dilatation catheter. The balloon dilatation catheter comprise... more This invention relates to a balloon dilatation catheter. The balloon dilatation catheter comprises a first, inflation lumen extending therethrough and having distal and proximal ends, the distal end of the first lumen opening into and being in fluid communication with the interior of an inflatable dilatation balloon having distal and proximal ends, and a second lumen extending coextensively with and exterior to the dilatation balloon.
Water flow through point-of-use porous ceramic water treatment fil- ters have been theoretically ... more Water flow through point-of-use porous ceramic water treatment fil- ters have been theoretically analyzed in this technical paper. Filters tested were manufactured by combining low cost materials namely, clay and sawdust. Three filters with distinct volume fractions of clay to sawdust (75:25, 65:35 and 50:50) were tested. Sintered clay filters casted in frustum shapes were structurally char- acterized using mercury intrusion porosimetry. A linear increase in porosity with volume fraction of sawdust was observed. Flow experiments were carried out at constant room temperature and pressure. Potable tap water was used in these studies. Flows through filters occurring with drop in the head of water under gravity were statistically analyzed. Discharges through the filters were predicted with respect to independent variables of time for cumulative discharge and volume fraction of sawdust used for manufacturing the filters. The experimental data analysis predicts a multiplicative influence ...
Abstract Subsurface (tile) drainage is a necessary practice for economic crop production in humid... more Abstract Subsurface (tile) drainage is a necessary practice for economic crop production in humid, poorly drained regions of the world. Drainage water management (DWM), also known as controlled drainage, is among the suite of practices designed to mitigate water quality issues associated with subsurface drainage. Studies evaluating DWM generally include field experiments or simulation models to estimate water quality impacts. Combining field studies with model simulations can provide a more comprehensive assessment. Furthermore, using multiple approaches can provide a range of effectiveness rather than a single estimate, which can help define the uncertainty associated with DWM effectiveness. The goal of this study was to demonstrate the variability in estimated DWM effectiveness using 10 years of measured data and a calibrated hydrologic model. The study field, located in central Ohio, was under a free drainage (FD) mode from 2005 through 2008, and under DWM from 2009 through 2014. We used three approaches to compare discharge and nitrate concentrations and loads: before-and-after, paired-field, and DRAINMOD-NII simulated scenarios. Based on the three evaluation approaches, DWM increased surface runoff by 50% (∼13 mm), reduced annual drainage discharge between 8 and 23% (∼19 to 69 mm), annual mean NO3-N concentrations between −1 and 2.5%, and NO3-N loads between 9 and 25% (∼2.8 to 10.3 kg ha−1 yr−1). DWM also reduced the frequency of drainage discharge, and increased magnitudes of surface runoff, evapotranspiration, and seepage losses. The true magnitude of DWM effectiveness remains somewhat uncertain, especially in fields prone to seepage and runoff losses. However, using a combined assessment approach can help address the uncertainty associated with estimated DWM effectiveness at watershed and regional scales.
Abstract Although many sensitivity analyses using the soil and water assessment tool (SWAT) in a ... more Abstract Although many sensitivity analyses using the soil and water assessment tool (SWAT) in a complex watershed have been conducted, little attention has been paid to the application potential of the model in unique plots. In addition, sensitivity analysis of percolation and evapotranspiration with SWAT has seldom been undertaken. In this study, SWAT99.2 was calibrated to simulate water balance components for unique plots in Southern China from 2000 to 2001, which included surface runoff, percolation, and evapotranspiration. Twenty-one parameters classified into four categories, including meteorological conditions, topographical characteristics, soil properties, and vegetation attributes, were used for sensitivity analysis through one-at-a-time (OAT) sampling to identify the factor that contributed most to the variance in water balance components. The results were shown to be different for different plots, with parameter sensitivity indices and ranks varying for different water balance components. Water balance components in the broad-leaved forest and natural grass plots were most sensitive to meteorological conditions, less sensitive to vegetation attributes and soil properties, and least sensitive to topographical characteristics. Compared to those in the natural grass plot, water balance components in the broad-leaved forest plot demonstrated higher sensitivity to the maximum stomatal conductance (GSI) and maximum leaf area index (BLAI).
Abstract Subirrigation is employed to supply water to crop root zones via subsurface drainage sys... more Abstract Subirrigation is employed to supply water to crop root zones via subsurface drainage systems, which are typically installed for the purpose of excess soil water removal. Crop yield increases due to subirrigation have been demonstrated in numerous studies, but there is limited information regarding yield under future climate conditions when growing season conditions are expected to be drier in the U.S. Corn Belt. DRAINMOD was calibrated and validated for three locations with different soil series in northwest Ohio and used to investigate maize relative yield differences between subirrigation and free subsurface drainage for historic (1984–2013) and future (2041–2070) climate conditions. For historic conditions, the mean maize relative yield increased by 27% with subirrigation on the Nappanee loam soil, but had minimal effect on the Paulding clay and Hoytville silty clay soils. Maize relative yield under free subsurface drainage is predicted to decrease in the future, causing the relative yield difference between free subsurface drainage and subirrigation practices to nearly double from 9% to 16% between the historic and future periods. Consequently, the subirrigation practice can potentially mitigate adverse future climate change impacts on maize yield in northwest Ohio.
Drought during maize (Zea mays L.) growing season in the US Midwest can be mitigated using draina... more Drought during maize (Zea mays L.) growing season in the US Midwest can be mitigated using drainage and runoff water recycling through subirrigation. Limited information regarding subirrigation timing and intensity hinder its promotion across the region. Seven water table management strategies were simulated using DRAINMOD calibrated for three locations with different soil series in northwest Ohio, under 1984 to 2013 climate conditions, and were compared based on annual relative yield, subirrigation water volume, relative water discharge, and management intensity. Annual relative yields ranged between 63.1% and 64.4% at the Defiance site and were not significantly different between the water table management strategies. Under subirrigation, relative yields ranged from 87.3% to 93.2% and 80.4% to 90.8%, respectively, at the Fulton and Van Wert sites and were significantly larger than under free subsurface drainage. Annual subirrigation water volumes were significantly lower under continuous subirrigation from V3 stage at all three locations. Subirrigation water volumes at the Fulton and Van Wert sites were particularly lower with continuous subirrigation starting at V9. Relative water discharges were similar across all water table management strategies at the Defiance site and larger under free subsurface drainage at the Fulton and Van Wert sites. Free subsurface drainage was the most appropriate option for the Defiance site in terms of water table management because subirrigation did not improve the relative yield but consumed water (and, consequently, energy for pumping). For the Fulton and Van Wert sites, continuously subirrigating from V9, with the control weir set at 61 cm below ground surface and raised to 35 cm below ground surface at tasseling improved the relative yield while using less subirrigation water volumes and generating no greater relative water discharge (hence no greater dissolved nutrient loads) than the other subirrigation options. This strategy potentially reduces labor costs at locations where subirrigation is appropriate, enhancing the economic viability of subirrigation, and is the most applicable strategy to other major maize-growing areas in the Midwest. Results indicate water table management and subirrigation will benefit Midwestern maize production under projected climates, which suggests increased potential for water stress in most growing seasons by 2041 to 2070. Future studies, extending this approach to more diverse regions, accompanied by more in-depth economic assessments, are needed to further evaluate potential benefits of subirrigation.
Drained lands, which include some of the most productive lands in the world, can experience both ... more Drained lands, which include some of the most productive lands in the world, can experience both water excess and water deficit within a year. Storing drained water within the landscape could increase the sustainability of water for agriculture, particularly as intense rainfall and prolonged summer drought continue to increase under future climate change. A team of researchers and extension specialists from nine states are currently working towards a vision of transforming the process of designing and implementing agricultural drainage to include storage through the use of controlled drainage, saturated buffers, and drainage water recycling (i.e. capture, storage, and reuse). Field research data from experimental drainage sites from across the U.S. Corn Belt have been brought together in a database to support synthesis and modeling to determine economic and environmental impacts of drainage water storage. Results from this effort will extend the strategies and tools to agricultural producers, the drainage industry, watershed managers, agencies, and policy makers, and educate the next generation of engineers and scientists to design drainage systems that include water storage in the landscape.
Abstract This study investigates long-term trends of three different time scales including monthl... more Abstract This study investigates long-term trends of three different time scales including monthly, seasonally and annually at the upper Senegal River basin. Daily streamflows for the period 1961–2014 at Bafing Makana station were used and analyzed to conduct this research. The serial structural of the different time series (monthly, seasonal, and annual) were investigated in order to detect the presence of autocorrelation. Mann–Kendall test was applied to no autocorrelated series and the Modified Mann–Kendall test for the autocorrelated. Theil and Sen’s slope estimator test was used for finding the magnitude of change and Pettitt test was applied for detecting the most probable change year. Results exhibited a decreasing trend of the annual streamflow yet at the 5% significance level, streamflow series did not have any statistically significant trend for the whole period; however, integrating the different change years, decreasing trend is significant before the first breaking point (1976) and increasing trend is significant from first breaking point to the second change point (1993). For the monthly series, all months exhibit a non-significant decreasing trend except for the month of June. The seasonal series show a decreasing trend which a significant at MAMJ season. Change years were varying accordantly to the scale.
Based on the hydrological characteristics of a rice-based irrigation system in Southern China, th... more Based on the hydrological characteristics of a rice-based irrigation system in Southern China, the SWAT (Soil and Water Assessment Tool) model was modified in order to develop the Rice Irrigation System-Soil and Water Assessment Tool (RIS-SWAT). The irrigation water movement, water balance module, and rice yield calculations of the paddy field were improved within the SWAT model. In addition, the seepage of the irrigation canal and the pond’s effect on the irrigation modules were added to the RIS-SWAT. The impact of water management on the water cycle of the small watershed irrigation system (SWIS) was evaluated by conducting a scenario analysis with RIS-SWAT. The results indicated that an increase in the maximum water ponding depth of a paddy field could decrease irrigation water and rainfall loss. The canal water supply was reduced by 20%, resulting in an increase in irrigation water productivity without a reduction in the rice yield. The temporal and spatial distributions of the irrigation water in different subbasins did not significantly affect the water cycle within the SWIS. Furthermore, when the canal water supply was reduced by 20–40% and the pond water supply was increased, the rice yield was not affected. Thus, the water productivity of irrigation systems could be improved through the implementation of water management policies and practices that reduce field outflows and reuse the return flows captured by ponds.
ABSTRACT A workshop on Liquid Animal Manure Application on Drained Cropland: Preferential Flow Is... more ABSTRACT A workshop on Liquid Animal Manure Application on Drained Cropland: Preferential Flow Issues and Concerns (Columbus, Ohio; November, 2004) was conducted to prioritize extension and research activities in the Midwest. Seven extension priorities were identified: 1) Integrate simple manure application rules into the whole farm plan. 2) Required certification and continuing education credits for manure applicators. 3) Develop web-based fact sheets, video clips, and photos and use demonstrations to educate livestock producers on preferential flow issues. 4) Promote partnerships with agencies, industry, producers, and universities. 5) Develop educational programs for agency personnel on preferential flow issues related to manure application. 6) Develop computer programs to apply manure at a safe application rate. 7) Integrate manure management for liquid manure application into other programs. The top 17 research ideas were identified as well: 1) Pathogen transport and fate rated the highest. 2) Research soil types, water holding capacity, and preferential flow characteristics of soil. 3) Research manure characteristics. 4) Study application methods, application equipment and tillage methods. 5) Develop liquid manure testing methods, sensors, quick tests, and cost effectiveness of testing parameters. 6) Correlate factors from past manure violations cases into a national database. Other research priorities looked at developing alternative technology, adding value to the manure, research on precision application and variable rate technology, researching socio-economic data, water table control structures, water columns studies related to groundwater, storage/handling/application options, fate of liquid manure in agricultural subsurface drains, and developing parameters for manure characteristics.
9th International Drainage Symposium held jointly with CIGR and CSBE/SCGAB Proceedings, 13-16 June 2010, Québec City Convention Centre, Quebec City, Canada, 2010
Best practices for managing drainage water quality include the use of constructed wetlands for re... more Best practices for managing drainage water quality include the use of constructed wetlands for reducing nutrient loads. Nutrient reduction can be related to the hydraulic performance of a wetland. Hydraulic indexes used for quantifying the hydraulic efficiency of a wetland have more value when they can be used to predict treatment ability. This paper evaluates a number of common indexes describing hydraulic efficiency and relates them to the expected treatment derived from time dependant first order nutrient reductions. There is a need for a hydraulic index demonstrating strong correlation to pollutant reduction in order to identify the optimal wetland configuration for maximizing residence time. Such an index should quantify the effects of the various wetland parameters that influence the residence time distribution and supply the bounds for pollutant reduction.
This project calibrated and validated DRAINMOD 5.1 for prediction of nitrate concentrations in dr... more This project calibrated and validated DRAINMOD 5.1 for prediction of nitrate concentrations in drainage water from conventional and combined (controlled/subirrigated) drainage plots. Weather, soil, water quality and hydrology data collected at Piketon, Ohio during 1996 and 1997 were used. Results indicated that DRAINMOD 5.1 was able to predict daily water table heights (within 30 cm) for both conventional and combined drainage practices on Omulga silt loam soil. DRAINMOD 5.1predicted cumulative nitrate loads adequately for conventional drainage. Predictions for combined drainage consistently overestimated the nitrate loads, perhaps because the nitrogen cycle rate reactions were not modeled as a function of soil water content, or because the plant removal of N was too low.
Improved subsurface drainage continues to be a priority for agricultural producers in Ohio. Much ... more Improved subsurface drainage continues to be a priority for agricultural producers in Ohio. Much of the subsurface drain pipe is installed by specialty drainage contractors. Little research has been reported concerning the design practices and characteristics of subsurface drain installers. To develop background information for the Ohio Agricultural Water Management Guide, a mail survey was conducted to inventory contractor practices and estimate the extent of subsurface drainage installation from 1995-1997. Respondents were classified into two categories: those which installed subsurface drainage as their main business, and those for which it is a sideline business. Over 90% of the mainline firms had been in business for 11 years or more. Respondents reported the installation of over 10 000 km of drain pipe in 1997. Relatively few controlled drainage and sub-irrigation system installations were reported. Mainline firms installed about 90% of the total drain pipe installed. These firms rely on experience and self-generated topographic maps as their primary design aids. Many contractors reported the same drain depth and spacing for different soil series, suggesting that the soil type is not a main consideration in the installation. Further education and training may be needed to improve the design practices used by Ohio drainage contractors KEYWORDS. Agricultural drainage, drainage contractors, drain installation practices, drain spacing, drain depth.
Prediction of solar radiation is needed for a wide range of applications, such as for predicting ... more Prediction of solar radiation is needed for a wide range of applications, such as for predicting daily evapotranspiration. In our case, prediction of solar radiation is important for estimating power and energy needs. Predicting clear day radiation is a clear process, while predicting cloudy day radiation can be more complex. Having a capability to predict solar radiation for locations with no or very few data is an important need that we are trying to address. The Hargreaves and Samani model estimates for daily solar radiation in Wooster OH had good correlation between model prediction error and average solar radiation throughout year. To conduct a more appropriate assessment of results, we found that the RMSE should be calculated for a dry, a humid, and an average year, instead of calculating a general RMSE for the whole period. Choosing the model constant based on the difference between max and min daily temperature can improve predictions. Several modified versions of the Hargreaves and Samani model, such as the Allen selfcalibrating model, a lower-limit calibrating model based on relative humidity, and several combinations of these models, were used to evaluate using the models to produce probability distributions for solar data, and predicting statistical upper and lower limits of data in Ohio. The error analysis shows that the models with a combination of self-calibrating for the upper and lower solar radiation were more successful in predicting the expected solar limits.
ABSTRACT A denitrifying bioreactor is a system where a carbon substrate (commonly woodchips) is u... more ABSTRACT A denitrifying bioreactor is a system where a carbon substrate (commonly woodchips) is used to reduce nitrate concentration in water flow. For many years, water flow through woodchips has been assumed laminar without proper validation. The main objective of this study was to validate Darcy’s laminar flow assumption for woodchips. For this purpose, we conducted both constant head laboratory column experiments and field evaluation of a denitrification bed. Laboratory results revealed that Darcy’s law does not apply for the majority of the hydraulic gradients forcing flow through fresh and old woodchip media. However, Forchheimer’s equation adequately described the flow pattern using a quadratic equation. Statistical analysis showed that old woodchips (excavated from a denitrification bed) had significantly lower intrinsic permeability than fresh woodchips. We determined Forchheimer’s and Darcy’s in-situ coefficients, and used them to predict flow rate in a denitrification bed. Model evaluation statistics showed better flow rate prediction with Forchheimer’s than Darcy’s equation when compared with the measured flow rate. In conclusion, the linear flow assumption was inadequate for describing water flow through woodchips in a denitrification bed.
... Experimentation of New Resource Conserving Technology in Synergy with Micro-Turbo-based Canal... more ... Experimentation of New Resource Conserving Technology in Synergy with Micro-Turbo-based Canal Irrigation System Anand Krishnan Plappally, The OSU, Columbus, OH, USA Ravi Shankar Tripathi, RWC-CIMMYT, Delhi, India PMV Subbarao, PhD, Professor, IIT, Delhi, India ...
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