Sustainable Management of Dams and Reservoirs in North Dakota: Sediment Transport Characterization

Selected reservoirs in the state of North Dakota was surveyed to assess their storage capacity, sedimentation characteristics, water quality parameters, and check for leakage. The purpose of the study is to understand the dynamic of reservoir sedimentation in North Dakota and the effect on its resiliency and sustainability. The HYCAT, which is an autonomous surface vehicle, was interfaced with a side scan sonar and global positioning system. The side scan sonar soundings at a determined frequency was used to measure reservoir bed level and deposited sediments while the positioning system would provide information along the grid lines. Additionally, this bathymetry data was compared to previous survey data from reliable databases to evaluate storage capacity and storage loss or gain over the years. The water quality parameters of the selected reservoirs were monitored using the EX02 Sonde. This informed further discussion on the suitability of the reservoir to perform the functions for which it was originally designed. While sedimentation is the immediate concern, other studies that will be investigated in stage two of this research would be to investigate the factors affecting PFAS distribution along the reservoir.https://commons.und.edu/cie-pp/1001/thumbnail.jp

Salts Removal as an Effective and Economical Method of Bakken Formation Treatment

One of the main aims of managing and containing waste disposal in deep rock formations is to safeguard individuals, the surroundings, and the groundwater reserves The elevated salt content of the water produced by the rock formation necessitated an analysis of its chemical composition, including its major ion content, in order to understand the characteristics of the rock Additionally, the total dissolved solids ( in the ND Bakken formation are greater than 300 g/l, which is much higher than the concentration of salt in seawater therefore, it is reasonable to propose a modified process to treat the salts found in this formation produced water Produced water in the unconventional U S Bakken oilfield has become a significant concern since oil and gas production growth has been substantial, and operating costs are increasing Reusing this considerable amount of produced water has become necessary since the treated water can be used for potable supplies, irrigation, deep well injection, maintenance, and fracking, which improves profits and mitigates groundwater pollution Several metals ( Ca, Mn, Sr, Li, and K) were extracted from the flow back water and water produced in the Bakken oilfield using lime, caustic soda, and soda ash at different dosages and pH values during this project The separation treatment using selective precipitation can be invaluable as a pre treatment process of desalination techniques Extracted salts are effective coagulants for removing various contaminants from wastewater therefore, the extracted Mg(OH) 2 and CaCO 3 were used for wastewater treatment and establish their efficiency in removing COD and the nutrients phosphorous and nitrogen from ND wastewater The recovery of these elements from produced water may create additional financial benefits for oil producing areas More importantly, this sustainable disposal of produced water may encourage the recycling and reuse practice, ultimately reducing the use of freshwater for hydraulic fracturinghttps://commons.und.edu/cie-pp/1000/thumbnail.jp

Climate Change Impacts on North Dakota: Agriculture and Hydrology

North Dakota is one of the principal producers of agricultural commodities in the USA, including over half of the total spring wheat production. While the region includes some of the best agricultural lands in the world, the steep temperature and precipitation gradients also make it one of the most sensitive to climate change. Over the 20th century, both the temperature and the pattern of precipitation in the state have changed; one of the most dramatic examples of the consequences of this change is the Devils Lake flooding. In two studies, we estimated the climate change impacts on crop yields and on the hydrology of the Devils Lake basin. The projections of six GCMs, driven by three SRES scenarios were statistically downscaled for multiple locations throughout the state, for the 2020s, 2050s, and 2080s climate. Averaged over all GCMs, there is a small increase in precipitation, by 0.6 - 1.1% in 2020s, 3.1 - 3.5% in 2050s, and 3.0 - 7.6% in 2080s. This change in precipitation varies with the seasons, with cold seasons becoming wetter and warm seasons not changing

Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial

Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma. Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding. Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries. Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to 100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable. This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124. Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid (5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18). Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of 5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98). Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a randomised trial

Design flood estimation methods for rivers with extensive tidal interaction zones

Flooding problems may never be solved as long as people live in proximity of riverbanks with high inundation risk. A rational approach well embraced by civil engineers is to derive flood estimates and adopt mitigation measures corresponding to an acceptable risk level. However similar approaches have not been well addressed in many rivers with extensive tidal interaction zones (TIZ), such as those found in Sarawak, Malaysia. -- The primary objective of this research is to streamline and develop a set of design flood estimation methods applicable to the TIZ with varying degrees of sophistication. Methods in use such as the direct frequency analysis method, the regression-like rating-curve method, the joint probability method and the hydrodynamic modelling method are evaluated. Although these methods have their merits, they have many inherent limitations and constraints. Two new methods that are statistically based yet do not compromise the physical meanings of the processes involved are developed. The first is a low-pass filter method involving Fourier transforms resulting in filtering of low frequency river level series. A second new method is based on wavelet de-noising techniques that considers tidal contributions as noise in a smooth function. An algorithm ensuring a consistent separation technique is developed. Various wavelet families are investigated together with different decomposition levels and thresholding options. Conventional flood frequency analysis techniques are subsequently applied directly to the separated flow series. -- The secondary objective of this research is to establish a comprehensive flood estimation procedure for ungauged catchments in the study area based on regional flood frequency analysis. The need arises because inflow floods deriving from the major ungauged tributaries, which affect flows in the TIZ, have to be estimated in some of the methods. -- After comparing all the methods, it is recommended that an appropriate number of water-level observation stations should be established at strategic locations in the TIZ on a continuous long-term basis. With these data, the effects of climatic change on sea level rise and the subsequent effects on flood estimations in the TIZ can be assessed accurately. -- In conclusion, the method to be chosen for design flood estimations in the TIZ is very much dependent on data availability. If long-term water level data in the TIZ is available, the new fundamental method using wavelet de-noising gives direct and reliable results. By considering the interaction effects, it is superior to the conventional direct frequency analysis. Since wavelet methodology is still evolving, there are further potential applications for this particular method

Regional flood estimation for ungauged basins in Sarawak, Malaysia

Abstract Design flood estimation is an important task that is required in the planning and design of many civil engineering projects. In this study, the flood records of more than 23 gauged river basins in Sarawak, Malaysia, are examined using an index-flood estimation procedure based on L-moments. Two homogeneous regions were identified and the Generalized Extreme Value and the Generalized Logistic distributions are found to describe the distribution of extreme flood events appropriately within the respective regions. A regional growth curve is subsequently developed for each of the regions. These curves can be used for the estimation of design floods in ungauged basins in Sarawak within the limitations identified for the method. The results presented herein are useful for practicing engineers in Sarawak while the general methodology may be used in any other regions, provided flood records are available

Regional flood estimation for ungauged basins in Sarawak, Malaysia

Design flood estimation is an important task that is required in the planning and design of many civil engineering projects. In this study, the flood records of more than 23 gauged river basins in Sarawak, Malaysia, are examined using an index-flood estimation procedure based on L-moments. Two homogeneous regions were identified and the Generalized Extreme Value and the Generalized Logistic distributions are found to describe the distribution of extreme flood events appropriately within the respective regions. A regional growth curve is subsequently developed for each of the regions. These curves can be used for the estimation of design floods in ungauged basins in Sarawak within the limitations identified for the method. The results presented herein are useful for practicing engineers in Sarawak while the general methodology may be used in any other regions, provided flood records are available

Hydraulic Transient Analysis of Sewer Pipe Systems Using a Non-Oscillatory Two-Component Pressure Approach

On the basis of the two-component pressure approach, we developed a numerical model to capture mixed transient flows in close conduit systems. To achieve this goal, an innovative Godunov finite-volume numerical scheme is proposed to suppress the spurious numerical oscillations occurring during rapid pipe pressurization. To dissipate the spurious numerical oscillations, we admit artificial numerical viscosity to the numerical scheme through applying a proposed Harten, Lax, and van Leer (HLL) Riemann solver for calculating the numerical fluxes at the computational cell interfaces. The proposed solver controls the magnitude of the numerical viscosity through adjusting the left and right wave velocities. A wave velocity calculator is proposed to optimally distribute the numerical viscosity over several computational cells around the computational cell in which the pressurization front is located. The proposed solver admits significant artificial numerical viscosity when the pipe pressurization is imminent and automatically reduces it in other places; in this way the numerical diffusion and data smearing is minimized. The validity of the proposed model is justified by the aid of several test cases in which the numerical results are compared with both experimental data and the results obtained from analytical methods. The results reveal that the proposed model succeeds in completely removing the spurious numerical oscillations, even when the pipe acoustic speed is over 1000 m/s. The numerical results also show that the model can successfully capture occurrence of negative pressures during the course of transient flow

Calculating Column Separation in Liquid Pipelines Using a 1D-CFD Coupled Model

This paper proposes a coupled 1D-CFD model for calculating column separation in liquid pipelines. ANSYS Fluent is utilized to calculate two-phase flow analysis. Method of Characteristics and Discrete Gas Cavity Model (DGCM) are both employed to conduct 1D transient analysis. The results show that the proposed model, with both 2D and 3D CFD analysis, captures the transient responses of the system that have nearly identical accuracy and are both consistent with the results of a physical experiment. The results of a pure CFD analysis are employed to evaluate the performance of the proposed model in capturing the shape of the vapor cavity. The comparison shows that the results are generally consistent. However, the vapor cavity in the pure CFD model is established and grown on top of a film of liquid, while the cavity in some places fills the whole pipe cross-section in the proposed model. In addition, the results obtained from using Modified Two-Component Pressure Approach (MTPA), an open-channel based model proposed by the authors, also confirm the results obtained from the pure CFD analysis. Some minor discrepancies are found, which may be attributed to the uniform velocity distribution considered at the interface between 1D and CFD zones

A Mixed Flow Analysis of Sewer Pipes with Different Shapes Using a Non-Oscillatory Two-Component Pressure Approach (TPA)

This paper aimed to justify the performance of a non-oscillatory TPA-based model proposed by the authors for capturing transient mix flow in sewer systems consisting of a variety of pipe shapes. The model utilizes a first-order Godunov Finite volume numerical scheme in which a Harten–Lax–van Leer (HLL) Riemann solver was used for calculating the fluxes at the cells’ boundaries. The spurious numerical solution associated with the transient mix flow analysis is suppressed by enhancing the numerical viscosity of the scheme when the pipe pressurization is imminent. Due to the lack of experimental data for systems with pipe shapes other than circular and rectangular, a hypothetical pipe system for which analytical solutions exist was employed to verify the model performance. The results reveal that for all pipe shapes considered, the model provides oscillation-free solutions even at a high acoustic speed of 1400 m/s. It is also observed that the numerical results are in perfect agreement with the analytical solution. The obtained results conclude that the proposed model can be utilized to capture transient responses of sewer systems with any pipe shape