Drainage Discharge Research Articles

FEM Analysis on Isotropic Consolidation of Unsaturated Soils Using Ceramic Disks and Microporous Membrane Filters for Suction Control

Abstract Microporous membrane (MM) filters with a significantly thin thickness have recently been used as an alternative to ceramic disks for matric suction control in the axis-translation technique for element tests on unsaturated soils. Although researchers have highlighted some discrepancies in test results when ceramic disks and MM filters are used, the mechanism leading to these discrepancies has not yet been clarified. In this study, suction-controlled triaxial tests were first conducted on unsaturated completely decomposed granite using two filters. Then, it is natural to believe that the different thicknesses of ceramic disk and MM filters may significantly influence the suction equilibrium process of specimens. To clarify this issue, soil-water-air coupled finite element modeling was performed to simulate the consolidation process in triaxial tests as an initial/boundary value problem. In the numerical calculation, the influence of the void ratio on the water retention curve (WRC) of soil was properly considered by adopting a deformation-dependent WRC model. In particular, the ceramic disk and MM filter, along with the specimens, were modeled, and their differences in thickness were considered. The calculated results show that a nonuniform distribution of suction occurred in the ceramic disk, leading to greater drainage discharge of the specimens. In other words, the influence of the thickness difference between the MM filter and ceramic disk cannot be neglected. However, regardless of whether ceramic discs or MM filters are used, the uneven distribution of the state variables in the specimens may occur in the triaxial tests for unsaturated soils, which emphasizes the importance of assessing the soil tests using the present axis-translation technique as initial/boundary value problems.

Simulating controlled drainage and hydrological connections in a cultivated peatland field

AbstractCultivated peatlands are increasingly regarded as hot spots due to climate change and other environmental concerns. Flexible water management, such as controlled drainage, is proposed to optimize cultivation and reduce environmental risks in peatland fields. The hydrological and environmental implications of controlled drainage depend on site‐specific variables, and it is unclear how controlled drainage should be implemented in various conditions. Simulation models are a promising approach to systemically study the field hydrology, as models can capture the complete water balance, which is difficult through experimental studies alone. We calibrated and validated the spatially distributed model FLUSH to describe the hydrology of a field block with a shallow peat cover and controlled drainage in central western Finland. The objectives were to analyze the hydrological effects of controlled drainage and detect hydrological connections between the field and an adjacent upslope forest area. The results showed how inflow from the forest can induce high observed drain discharge but impacted the block groundwater tables only in the proximity of the forest (distance <25 m). The effect of controlled drainage on groundwater tables was on average 0.15 m and seasonally varying. Controlled drainage reduced drain discharge, and the reduction was larger with the forest area included in the model. While controlled drainage effects on groundwater levels and soil moisture were insensitive to groundwater influxes from adjacent areas, the water balance impact highlights the role of hydrological connections in the hydrology of cultivated peatlands under controlled drainage.

Risk factors of pancreatic fistula after distal pancreas resections: an observational retrospective study

BACKGROUND: The main complication of surgical pancreas interventions is the pancreatic fistula (PF) — abnormal secretion of pancreatic secretions into the abdominal cavity, which can lead to more severe complications. At the same time, some predictors of PF remain poorly understood. AIM: To investigate the risk factors for the development of PF after distal pancreatic resection. MATERIALS AND METHODS: The study included 40 patients who underwent distal resection. The influence of various clinical parameters on the development of PF after surgery was evaluated. Methods of mathematical modeling and correlation analysis were used. Mathematical modeling was carried out using the Random forest machine learning algorithm, and the indicator of the relative importance of the “importance” parameters was evaluated. RESULTS: According to the Random forest model, on day 1 after surgery, the most significant predictors of the development of PF were: the volume of neoplasm, age and stage of the oncological process, for which “importance” was 53.2, 13.7 and 12.5 (AUC ROC=62%); on day 3–5, “importance” was 61.7, 11.5 and 5.2 (AUC ROC=79%). An increase in the concentration of pancreatic amylase in blood plasma for 2–3 and 3–5 days correlated with its increase in the drainage discharge for 5-7 days after the intervention (r=0.48 and 0.76; p 0.05). A correlation was found between the level of amylase in the drainage discharge on 3–5 days after the intervention and the level of leukocytes according to the general blood test (r=0.62, p 0.05). CONCLUSION: An increase in plasma amylase levels is the main risk factor for the development of PF. An increase in the concentration of amylase in the drainage discharge can be considered as a potential risk factor for the development of pancreatic fistulas with clinical manifestations in the following days. The stage of the oncological process, the size of the neoplasm and the age of the patient are also risk factors.

Increased sugarcane productivity and environmental improvement in acid sulfate soils: A win–win system

AbstractThis paper describes a sugarcane farming system on acid sulfate soils (ASS) in coastal, eastern Australia which has improved crop production, increased carbon sequestration, enhanced soil health and controlled drainage discharge to estuaries. The farming system has evolved as a collaboration between innovative sugarcane farmers, researchers and government agencies. The collaboration started when discharge from the farmed coastal floodplain ASS acidified an entire estuary in eastern Australia, wiping out all gilled and benthic organisms for 18 months. The event produced major conflicts between fishers, farmers, the community, entrained researchers and local and state governments. It led to a major initiative to develop sugarcane farming systems which enhanced environmental benefits and increased crop production. Such a win–win system has applicability to other locations with variable resource use conflicts. The system of cane land management adopted on the Tweed site is described.

A comprehensive assessment of water quality in Fayoum depression, Egypt: identifying contaminants, antibiotic pollution, and adsorption treatability study for remediation

This study aimed to assess the current water quality status across various regions within the Fayoum depression by examining water canals, drains, and potential contaminants impacting public health and the local ecosystem. Additionally, an adsorption treatability investigation was conducted on various antibiotics identified during the assessment. Fifteen sampling points were selected across the Fayoum depression, covering surface water bodies and agricultural drainage systems during both winter and summer seasons. Physico-chemical, microbiological, and antibiotic analyses were performed on collected water samples. The water quality parameters investigated included pH, electrical conductivity, total dissolved solids (TDS), total coliforms, fecal coliforms, and concentrations of antibiotics such as ciprofloxacin and tetracycline. The findings revealed significant variations in water quality parameters among different water sources, categorizing them into three types: irrigation canals, polluted canals, and drains. High contamination levels were observed in certain water canals and drains due to untreated sewage and agricultural drainage discharge. Notably, elevated TDS levels (exceeding 1200 mg/L), microbial indicators count (with total coliforms reaching up to 2.3 × 106 CFU/100 mL), and antibiotics (with concentrations of ciprofloxacin and tetracycline exceeding 4.6 µg/L) were detected. To mitigate antibiotic contamination, a Phyto-adsorption treatability study using magnetite nanoparticles prepared with Phragmites australis plant extract demonstrated promising results, achieving complete removal of high antibiotic concentrations with an adsorption capacity of up to 67 mg/g. This study provides updated insights into water quality in the Fayoum depression and proposes a novel approach for addressing antibiotic contamination, potentially safeguarding human and environmental health.

Isotope hydrology of the intermontane Elk Valley, British Columbia: an assessment of water resources around coal mining operations

ABSTRACT This study aimed to synthesise and interpret stable isotopic data (δ 2H and δ 18O) from various sources to understand the isotope hydrology around coal mine operations in Elk Valley, B.C., Canada. The data, including precipitation, groundwaters, seeps, and mine rock drains, were used to construct a local meteoric water line (LMWL) for the Elk Valley, evaluate the spatiotemporal isotopic composition of its groundwater, and assess mine seepage and mine rock drain discharge. The study revealed a robust LMWL relation (δ 2H = 7.4 ± 0.2 · δ 18O – 4.3 ± 4.1). The groundwater and seep data indicated a winter season bias and a north–south latitudinal gradient, suggesting rapid near-surface groundwater flow without significant post-precipitation evaporation. Porewater isotope samples from unsaturated mine rock piles (MRPs) showed site-specific evaporation patterns, potentially due to convective air flows or exothermic sulphide oxidation. This research revealed the influence of groundwater and meltwater on rock drain discharge. Based on evaporative mass balance calculations, MRPs seasonally contributed ca. 5 %(December base flow) and 22 % (snowmelt) to drain discharge. The findings underscore the value of stable isotope data collections in the Elk Valley to help better define and quantify the hydrology–hydrogeology, including a better understanding of evaporative conditions in MRPs.

Clinical impact of various drain-fluid data for the postoperative complications after hepatectomy: criteria of prophylactic drain removal on postoperative day 1.

Prophylactic drains reported to be useful to treat postoperative bile leakage (POBL) and reduce re-intervention after hepatectomy. However, prophylactic drains should remove in the early postoperative period. This study aimed to assess the association between postoperative complications and the drain-fluid data on postoperative day (POD) 1. Medical records of 530 patients who underwent hepatectomy were retrospectively reviewed. We evaluated the drain-fluid data on POD 1, such as bilirubin (BIL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and drain discharge volume. These variables were compared between patients with and without postoperative complications such as POBL and abdominal abscess not due to POBL. POBL was found in 44 patients (8.3%), PHLF was in 51 patients (9.6%), and abdominal abscess not due to POBL was in 21 patients (4.0%). Regarding POBL, drain-fluid BIL concentration and drain discharge volume was higher in the POBL group (p < 0.001 and p < 0.001, respectively). However, drain-fluid AST, ALT, and ALP concentrations were not different between two groups. As to the abdominal abscess not due to POBL, all drain-fluid data were not significantly different. Multivariate analysis for predicting POBL showed that the drain-fluid BIL concentration ≥ 2.68mg/dL was an independent predictor (p < 0.001). In the subgroup analyses according to the type of hepatectomy, the drain-fluid BIL concentration was an independent predictor for POBL after both non-anatomical and anatomical hepatectomy. The drain-fluid BIL concentration on POD 1 is useful in predicting POBL after hepatectomy.

Temporal dynamics of contaminants in an estuarine system affected by acid mine drainage discharges

The estuary of Huelva is constituted by the common mouth of the Odiel and Tinto rivers, which are extreme cases of acid mine drainage contamination due to the Iberian Pyrite Belt, the world's largest sulfide mineral province. The drained acidic waters are subjected to seawater mixing and thus, to dilution and precipitation processes that drive the load of contaminants entering the oceanic environment. This research reports the distribution of major metal(loid)s present in the highly acidic waters across the entire Tinto and Odiel estuarine systems as they are subjected to acid mine drainage neutralization, until reaching the ocean. The datasets presented are divided in low- and high-flow periods, corresponding to dry/warm and wet/cold seasons, respectively. Iron and Al were almost entirely removed from solution with pH increase at both periods due to their precipitation as schwertmannite and basaluminite, respectively. These mineral phases also, controlled the behavior of As, Cu and Pb, which were removed from solution, with >90 % of their concentration ending up in the particulate phase due to sorption processes. However, at pH >7, As returned entirely to the dissolved phase at both sampled seasons because of desorption, similarly to Cu at the low-flow period. On the other hand, concentrations of Zn, Cd, Mn, Co and Ni in solution decreased only by dilution with seawater, with null partitioning to any sorption processes during estuarine mixing until reaching the Atlantic Ocean.

Removal and Recovery of Europium with a New Functionalized Mesoporous Silica-Based Adsorbent

The discharge of acid mine drainage (AMD), characterized by a high concentration of rare earth elements (REEs), poses a significant threat to the health of ecosystems surrounding water sources. The global market demand for REEs has experienced a notable surge in the past decade. Consequently, recovering REEs from waste streams like AMD not only benefits the environment but also offers financial advantages. Europium (Eu), the rarest among REEs, constitutes only 0.1% w/w in monazite and bastnaesite ores. Eu is extensively used in the production of phosphors, alloys, and additives, and is a critical raw material for developing smart devices, ranging from high-resolution color screens to circuitry. Traditional adsorbents typically exhibit limited selectivity towards REE recovery. Mesoporous silica materials, such as SBA15 (Santa Barbara Amorphous-15), provide excellent tunability and modification capabilities, making them an attractive and cost-effective alternative. This research focused on two key aspects: (i) evaluating the dynamic adsorption column performance of granulated SBA15–NH–PMIDA to preferentially recover Eu, and (ii) employing mathematical modeling to optimize the dynamic adsorption column’s operating conditions for real-world applications with a minimal number of experimental runs. Granulated SBA15–NH–PMIDA was chosen as the adsorbent due to its high adsorptive capacity and selectivity in capturing Eu. The study revealed that granulated SBA15–NH–PMIDA exhibited 57.47 mg/g adsorption capacity and an 81% selectivity towards Eu. Furthermore, SBA15–NH–PMIDA demonstrated preferential adsorption toward Eu in complex multi-component solutions, such as AMD. The linear driven force approximation model (LDFAM) provided an acceptable simulation (R2 &gt; 0.91) under varying operational conditions. This validates the use of the model as a tool to effectively simulate and optimize column experiments that used granulated SBA15–NH–PMIDA to recover Eu.

Strengthen sunflowers resilience to cadmium in saline-alkali soil by PGPR-augmented biochar

In the center of the Nile Delta in Egypt, the Kitchener drain as the primary drainage discharges about 1.9 billion m3 per year of water, which comprises agricultural drainage (75 %), domestic water (23 %), and industrial water (2 %), to the Mediterranean Sea. Cadmium (Cd) stands out as a significant contaminant in this drain; therefore, this study aimed to assess the integration of biochar (0, 5, and 10 ton ha−1) and three PGPRs (PGPR-1, PGPR-2, and PGPR-3) to alleviate the negative impacts of Cd on sunflowers (Helianthus annuus L.) in saline-alkali soil. The treatment of biochar (10 ton ha−1) and PGPR-3 enhanced the soil respiration, dehydrogenase, nitrogenase, and phosphatase activities by 137 %, 129 %, 326 %, and 127 %, while it declined soil electrical conductivity and available Cd content by 31.7 % and 61.3 %. Also, it decreased Cd content in root, shoot, and seed by 55.3 %, 50.7 %, and 92.5 %, and biological concentration and translocation factors by 55 % and 5 %. It also declined the proline, lipid peroxidation, H2O2, and electrolyte leakage contents by 48 %, 94 %, 80 %, and 76 %, whereas increased the catalase, peroxidase, superoxide dismutase, and polyphenol oxidase activities by 80 %, 79 %, 61 %, and 116 %. Same treatment increased seed and oil yields increased by 76.1 % and 76.2 %. The unique aspect of this research is its investigation into the utilization of biochar in saline-alkali soil conditions, coupled with the combined application of biochar and PGPR to mitigate the adverse effects of Cd contamination on sunflower cultivation in saline-alkali soil.

"Effects of floating aquatic vegetation and canal sediment on phosphorus in drainage discharges in agricultural canals: A case study in the everglades agricultural area, Florida"

Phosphorus (P) discharge from agricultural and urban drainage is known for causing downstream eutrophication worldwide. Agricultural best management practices that are designed to reduce P load out of farms target different P species from various sources such as fertilizers leaching and farm soil and canal sediment erosion, however, few studies have assessed the impact of floating aquatic vegetation (FAV) on canal sediment and farm drainage water quality. This study evaluated the impact of FAVs on canal sediment properties and P water quality in drainage canals in the Everglades Agricultural Area in south Florida, USA. Non-parametric statistical methods, correlation analysis, trend analysis and principal component analysis (PCA) were used to determine the relationship between FAV coverage with sediment properties and P water quality parameters. Results showed that FAV coverage was correlated with the highly recalcitrant and most stable form of P in the sediment layer (Residual P Pool). FAV coverage also correlated with the dissolved organic P (DOP) which was the smallest P pool (7 %) of total P concentration in drainage water, therefore FAV coverage had no correlation with farm P load. The trend analysis showed no trend in farm P loads, despite a decline in FAV coverage at farm canals over an 8-year period. Phosphorus content in the sediment surface layer was strongly associated with farm P load and had a significant correlation with particulate P (PP) and soluble reactive P (SRP) which constituted 47 % and 46 % of the total P concentration in the drainage water, respectively. Equilibrium P concentration assays also showed the potential to release SRP from the sediment layer. The P budget established for this study reveals that sediment stores the largest P mass (333 kg P), while FAVs store the smallest P mass (8 kg P) in a farm canal, highlighting the significant contribution of canal sediment to farm P discharges. Further research is required to evaluate the impact of sediment removal and canal maintenance practices that help reduce farm P discharges.

The effects of improved subsurface drainage on runoff and nitrogen leaching from a clayey field section

AbstractThe aim of this study was to investigate the effects of improved subsurface drainage installation on nitrogen (N) loss in drain discharge (DD) and topsoil layer runoff (TLR). Data on DD and TLR, as well as on concentrations of total, nitrate and ammonium N in the runoff components, were collected from four sections of an experimental field in southern Finland (June 2007–December 2018). Supplementary drains were installed in one of the field sections in June 2014, and the data from that section were compared with those from three reference sections. Differences between the sections were statistically analysed based on annual and monthly values of runoff components and concentrations, as well as the loads of N fractions. The results revealed that improved drainage increased the N load in the DD, reducing the load in the TLR. Changes in N loads were more clearly driven by changes in the runoff volumes rather than by changes in the N concentrations in the runoff waters. Before the drainage improvement, most of the total N load was nitrate (53%), while the share of rest N (fraction of the total N after the mineral N fractions were subtracted) was 45%. After improved drainage, the percentages of nitrate and rest N were 73 and 26%, respectively. The results demonstrate the importance of agricultural water management as the key driver for controlling nutrient loads.

MARKERS OF COMPLICATIONS AFTER LAPAROSCOPIC GASTRIC BYPASS IN PATIENTS WITH OBESITY

Introduction. Bariatric surgery is one of the most effective methods of treating morbid obesity, which allows for a long-lasting result. Along with the increase in the number of operative methods of obesity treatment, the relevance of issues related to postoperative complications is increasing. In recent years, the issue of using special checklists after surgery has been actively investigated. This will help optimize the process of monitoring patients' condition in the postoperative period.&#x0D; The aim of the study: to develop a check-list model to prevent the detection of complications after laparoscopic gastric bypass in obese patients.&#x0D; Materials and methods. On the basis of the developed checklist, a study of the condition of obese patients, who underwent laparoscopic gastric bypass during 2019-2023, was conducted on the basis of the Department of General Surgery No. 2 of the Bogomolets National Medical University. The checklist included the following criteria: the level of pain on the VAS scale, the level of nausea, eating, mobility, whether there is a desire to be discharged home, abdominal muscle tension, pain in the calf muscles, heart rate, oxygen saturation in the blood, the number drainage discharge within 24 hours, temperature, systolic blood pressure, central venous pressure, laboratory diagnosis, decrease in hemoglobin concentration, leukocyte level after surgery, C-reactive protein level after surgery, blood procalcitonin level, erythrocyte sedimentation rate level, the presence of a shift in the leukocyte formula to the left. The presence of complications was assessed, the parameters of the checklist were analyzed using univariate logistic regression and ROC analysis for early detection of complications and determination of the chance of complications in the future.&#x0D; Results. Complications occurred in 18/218 (8.2%). The most frequent complication was bleeding in 6/18 (33.3%). Reoperation was performed in 12 cases of 12/18 (66.6%), endoscopic treatment was performed in 1 case, and conservative methods were used in 5 cases. According to the checklist, 31.81% had a positive predictive value (PPV) and 99.56% had a negative predictive value (NPV). The optimal cut-off point of the total score of the checklist was 6. Patients with a positive prognosis of the checklist have a higher chance of developing complications of VSH – 4.5 (95% CI 1.8-9.72), p &lt;0.001.&#x0D; Conclusions. The complication rate was 18/218 (8.2%). According to the checklist, heart rate, systolic blood pressure and mobility are very good predictors of postoperative complications. The checklist is the best option for determining the readiness of patients to be discharged from the hospital due to a high prognostic negative result. Due to the low prognostic positive result, the evaluated checklist needs additional modification and optimization taking into account the results already obtained.

Characterization of drain discharge from subsurface drainage system with 40 m lateral spacing in saline vertisols of Tungabhadra command area

Characterization of drain water for irrigation over the cropping (rice) season was assessed during rabi 2020-21 at Agricultural Research Station, Gangavati in the Tungabhadra Command Area (TBP). Drain water samples collected fifteen times over the cropping season from man holes revealed that the pH and EC values of drain water varied from 7.33 to 7.00 with a mean of 7.16 and 6.64 to 5.94 dS m-1 with a mean of 6.22 dS m-1 respectively. The SAR and RSC values in drain discharge varied from 21.80 to 14.60 (mmol/L)1/2 with a mean value of 17.20 (mmol/L)1/2 and from 13.20 to 0.00 me L-1 with a mean value of 2.69 me L-1. The DCR and SSP in drain discharge varied from 0.28 to 0.17 with a mean value of 0.23 and from 83.3 to 71.8 with a mean value of 76.5 respectively. The Mg/Ca and Cl/SO4 ratios in drain discharge varied from 12.70 to 0.29 with a mean value of 1.92 and from 0.63 to 0.31 with a mean value of 0.49 respectively. Due to higher values of EC, SAR, RSC and SSP then the recommended quality standards of irrigation water quality, at present the drain water was found not suitable to be used directly for irrigation purposes.

Characterization of drain discharge from subsurface drainage system with 60 m lateral spacing in saline Vertisols of Tungabhadra command area

Characterization of drain discharge from subsurface drainage system with 60 m lateral spacing in saline Vertisols of Tungabhadra command area

Utilization of aquatic biomass as biosorbent for sustainable production of high surface area, nano- microporous, for removing two dyes from wastewater

The majority of environmental researchers are becoming increasingly concerned with the manufacture of inexpensive adsorbents for the detoxification of industrial effluents. To address one of the significant and well-known pollution issues with certain drains that act as hotspots and contribute to coastal pollution in Alexandria, this study aims to develop an economical, ecologically friendly sorbent. This study assessed the efficacy of a biomass-coated magnetic composite and a magnetic active adsorbent for the removal of two dyes from an industrially contaminated sewer using a wetland plant (Phragmites australis). Using magnetic biosorbent, the biosorption of Xylenol orange and Congo red ions from polluted drain discharge in Abu Qir Bay was evaluated in the current study. Using scanning electron microscopy imaging and Fourier transform infra-red analysis; the surface function and morphology of the nano-biosorbent were examined. At room temperature, the effects of initial dye concentration, pH, contact time, and nano-biosorbent concentration have all been investigated. The greatest percentages that nano-biosorbent can remove from Congo red and Xylenol orange are 97% and 47%, respectively. The removal of the initial Congo red concentration varied from 42 to 97%, while the removal of the initial Xylenol orange concentration varied from 30 to 47%. The adsorption capacity was shown to be strongly pH-dependent; capacity dose as pH value increased, with pH 10 being the ideal pH for Congo red and pH 6 being the ideal pH value for Xylenol orange. The adsorption capacity for Congo red varied between 0.96 and 3.36 and the adsorption capacity for Xylenol orange varied between 0.18 and 17.58. The removal capacity decreased from 3.36 to 0.96 mg/g when the biosorbent dosage was increased from 0.05 to 0.5 g/L for Congo red, in case of Xylenol orange, the removal capacity increased from 0.18 to 17.58 mg/g when the biosorbent dosage was increased from 0.05 to 0.5 g/L. The removal capacity of Congo red increases quickly with time and varied from 1.66 to 1.88 of contact time; while the removal capacity of Xylenol orange varied between 3.08 and 4.62 of contact time. For the dyes under study, kinetics and adsorption equilibrium were examined. Within 180 min, the equilibrium was attained because to the quick adsorption process. For Congo red and Xylenol orange, the highest adsorption capacities were 3.36 and 17.58 mg g−1, respectively. The equilibrium data were assessed using a number of isotherm models, including Langmuir, Freundlich, BET, and Tempkin, while the kinetic data were examined using a variety of kinetic models, including pseudo-first- and pseudo-second-order equations. The pseudo-second-order equation provides the greatest accuracy for the kinetic data and Langmuir model is the closest fit for the equilibrium data.

Effects of urban drainage inlet layout on surface flood dynamics and discharge

Drainage inlets, the primary conduits for surface floodwater into underground facilities, significantly influence the performance of a drainage system. This study employs a two-dimensional hydrodynamic model to investigate how drainage inlet distribution affects urban flood dynamics and drainage flow discharge. We first validate the model with dataset obtained in a dedicated experiment observing urban surface and drainage flows. We identified two common layouts of drainage inlets, namely straight-line distribution (SLD) and surround type distribution (STD), and based on the two layouts, we simulated detailed surface flood dynamics and drainage discharge under various urban flood conditions and inlet spacing scenarios. The results indicate that SLD exhibits higher drainage capacity in shorter time and greater total drainage volume under urban peripheral flood condition, while STD consistently outperforms in draining urban surface flooding induced by intense rainfall. It is also found that inlet spacing plays a crucial role in affecting drainage efficiency. To be specific, both layouts with medium spacing (l0 = 0.53 for SLD and 0.93 for STD) near flood-prone areas perform better when a sudden-onset peripheral flooding occurred; however, in the case of rainfall-induced flooding, maximizing inlet spacing and strategically distributing them across urban streets proves to be a more effective strategy for draining floodwater. Individual inlets near the ends of SLD and inlets at far-corners of STD shoulder higher drainage loads. This study provides valuable insights for optimizing inlet layout strategies under various urban flood conditions and improving floodwater collection.

Hydrological effects of open ditch damming and controlled subsurface drainage in a Nordic agricultural field

Abstract Controlled drainage (CRD) is an agricultural water management practice designed to adjust the capacity of a drainage system under varying hydrological conditions. This simulation study aimed to quantify the potential of combining a controlled subsurface drainage (CS) with open ditch damming (CD) to manage the water table depth (WTD) and field water balance in Nordic conditions. Simulations with and without controlled drainage were run using a hydrological model that had been set up for a flat loamy field in Northern Ostrobothnia, Finland, for the period 2010–2021. All CRD scenarios reduced the probability of deep WTDs during growing seasons (May–Sep). The impact of CS on WTDs was greater and more uniform than CD. The CRD effects on water balance were seen in water outflow pathways, as CS reduced drain discharge while CD had the opposite effect. When both methods were applied simultaneously, annual evapotranspiration increased 5–12% compared with the free drainage scenario. The effects of CRD on evapotranspiration were greatest during the dry years indicating that CRD has potential to reduce drought in food production areas. None of the CRD scenarios could maintain optimal WTDs during the entire growing season, highlighting the complexity of optimizing field water management using CRD alone.

Predicted Contribution of Snowmelt to Subsurface Drainage Discharge in Two Subsurface-Drained Fields in Southern Quebec and Ontario

Highlights RZ-SHAW model delivered a satisfactory simulation for winter subsurface drainage discharge. Snowmelt dominated the drainage discharge during the winter and spring snowmelt seasons in southern Quebec. Snowmelt contributed to 29% and 18% of winter and annual drainage discharge, respectively, in southern Ontario. Abstract. Late winter/early spring has been recognized as a critical period for subsurface drainage discharge and associated nutrient losses due to snowmelt and rainfall in croplands under cold, humid climates in North America and Europe. Although the detachment and transport processes of soil particles under snowmelt and rainfall are known to be different, studies quantifying the contribution of snowmelt to winter drainage discharge are limited. This study aims to investigate the contribution of snowmelt to subsurface drainage discharge at two winterized experimental sites in southern Quebec and Ontario, Canada, using observed data and the Root Zone Water Quality Model-Simultaneous Heat and Water model (RZ-SHAW model). The RZ-SHAW model was calibrated and validated against the measured snow depth and year-round subsurface drainage discharge data from 2021 to 2023 at St. Emmanuel, Quebec, and from 2000 to 2003 at Harrow, Ontario. RZ-SHAW demonstrated satisfactory Nash-Sutcliffe model efficiency values (NSE = 0.50) for simulating snow depth, soil temperature, and winter subsurface drainage discharge. The calibrated RZ-SHAW model was used to simulate the contribution of snowmelt to subsurface drainage for the two sites from 1990 to 2022. The snowmelt was predicted to contribute 55% and 44% of the winter and annual subsurface drainage discharge for the cropland in Southern Quebec. In contrast, for the southern Ontario site, the contribution of snowmelt to winter and annual subsurface drainage discharge was 29% and 18%, respectively. Considering that snowmelt in Southern Quebec contributed a significant fraction of winter and annual subsurface drainage discharge, more attention should be devoted to adapting and developing new winter management for nutrient loss in future research in the region. Keywords: Cold region, Cropland drainage, Drainage partition, RZ-SHAW, RZWQM2, Snowmelt, Soil freeze and thaw, Winter subsurface drainage.

Effects of Drainage System Design on Nutrient Leaching and Crop Yield

Highlights Tested drainage system designs had no clear effect on the total amount of drainage discharge. Tested drainage system designs had a clear effect on nutrient loads in drainage discharge. Corrugated plastic pipe drainage systems had higher N loads and lower P loads than tile drainage systems. Corrugated plastic pipe drainage systems gave higher yields than tile drainage systems and can be a profitable on-farm investment. Abstract. A clear strategy for adapting agricultural drainage to future climate change is important for environmental and economic reasons. In a study aimed at developing recommendations for the subsurface drainage design in clay soils, we evaluated the impact of replacing an old drainage system (1920) with new systems (2018) on nutrient leaching and crop yield. Our field experiment included 12 individually drained plots divided into four treatments: (A) old system with clay tiles at 10 m spacing, without an envelope; (B) new system with plastic pipes at 10 m spacing, gravel envelope; (C) new system with plastic pipes at 5 m spacing, gravel envelope; and (D) new system with plastic pipes at 10 m spacing, gravel envelope and lime incorporated in trench backfill. We conducted flow measurement and flow-proportional, logger-controlled water sampling of the drainage discharge from each plot at a measuring station. Preliminary results (first two years) show a clear effect of the new drainage systems on phosphorus and nitrogen loads in drainage discharge. The lowest total load of phosphorus and highest total load of nitrogen in all treatments were observed in treatment D (with 10 m drain spacing and lime incorporated in trench backfill). The highest total phosphorus load and lowest total nitrogen load in all treatments were observed for the old tile drainage system with 10 m drain spacing (treatment A). The environmental impact of new drainage systems on clay soils may thus be a trade-off between decreased phosphorus loads and increased nitrogen loads with more intensive drainage. Crop data from two experimental years indicated that investing in new drainage systems can be profitable for farmers, as crop yield was 3%-20% higher with new drainage systems compared with old tile drainage. More experimental years are needed to determine the long-term effects of the different drainage system designs. Keywords: Drain envelope, Drain spacing, Nitrogen load, Phosphorus load, Subsurface drainage.