Drainage Outlet Research Articles

Applications of remote sensing and GIS techniques to evaluate the effectiveness of coastal structures along Burullus headland-Eastern Nile Delta, Egypt

Burullus headland is located in the middle half of the Nile Delta Coast. It extends from Burullus inlet to the east to Kitchener drain outlet to the west. Burullus headland has several types of coastal protection structures, such as seawalls, groins, revetments, jetties, basalt riprap (rock wall), and detached breakwaters; these structures were constructed to mitigate coastal erosion. This study aims to compare rates of shoreline displacement prior to and after the construction of the aforementioned structures and to evaluate their efficiency in protecting Burullus headland from erosion during the period from 1973 to 2018. Multi-temporal satellite images and Digital Shoreline Analysis System software have been used to detect and quantify shoreline changes and to predict the shoreline position at 2030, depending on the resulted rates of shoreline displacement. The analysis showed that Burullus headland coast would be divided into four zones, according to the intensity of the erosion; these are: Zone A with accretion's rate of 0.67 m/year; Zone B, the most affected area by erosion with retreating rate of 4.32 m/year; Zone C, which includes 14 of detached breakwater, showed an accretion rate of 5.62 m/year; and finally, Zone D, which includes 9 groins, was characterized by retreating rate of 2.88 m/year. The results of this study show that some types of protection structures were not effective in mitigating coastal erosion in the case of Burullus headland. The predicted shoreline indicates continuous accretion in zone A and C and continuous erosion in zone B and D.

Numerical simulation study on diffusion of temperature drainage in wide and shallow water in a refinery integration project

The numerical simulation of tidal current field in wide and shallow waters (Naochao River) of Caofeidian industrial zone is carried out by using a two-dimensional hydrodynamic model, taking the discharge problem of temperature and drainage in a refinery integration project as an example. Taking the tidal current field as the hydrodynamic condition of the temperature drainage transport simulation, the concentration distribution of the temperature drainage in the receiving water area was predicted by using the two-dimensional convection-diffusion model of the temperature drainage, and the change of the temperature rise line and its influence were analyzed. The results showed that the water area affected by temperature rise in winter and summer were 0.28km2 and 0.35km2, respectively, when the project was discharged separately. The existing temperature displacement of China Resources Power Plant in the superposition area is: 19.1km2 in winter and 1.64km2 in summer under the influence of temperature rise. By analyzing the influence degree of wide and shallow water (Naochao River) drainage outlet on temperature rise, the conclusion that the layout of drainage outlet should be further optimized is given. conclusion that the layout of drainage outlet should be further optimized is given.

СИСТЕМА УПРАВЛЕНИЯ СОСТОЯНИЕМ ГИДРОТЕХНИЧЕСКИХ СООРУЖЕНИЙ И СОВЕРШЕНСТВОВАНИЕ ТЕХНОЛОГИЙ ЕГО ДИАГНОСТИКИ

The general purpose of real-time monitoring of the technical condition of hydrotechnical structures of reclamation systems is to detect the deterioration (deterioration of the condition) of the degree of physical wear and tear, the reasons that entail the deterioration of condition, a decrease in efficiency of the structure. Materials and methods. The studies carried out were based on general scientific methods: descriptions, comparisons, statistical analysis, systems approach and economic and mathematical modeling. The objects of diagnostics of the technical condition of the hydrotechnical structure of the reclamation water complex include: dams, hydroelectric power plant buildings, spillways, drainage and water outlets, tunnels, canals, locks, piezometric systems, power units, perimeters of the hydraulic system, bridges, foundations. Results. It has been determined that the control of the state indicators on most hydraulic structures is carried out visually and with the help of control and measuring equipment, mainly by destructive methods, manually. The high potential of the process of automation of operations of technical diagnostics of the structures of the reclamation water industry complex has been revealed. The modern complex information systems used in the advanced sectors of the economy of Russia and the world are characterized. Possibility of qualitative improvement and development of the system of automated technical diagnostics of hydraulic structures due to the priority use of modern achievements of information technologies is presented. Conclusions: the developed methodology makes it possible to improve information technologies for diagnostics of hydraulic structures, the reasonable use of such a system establishes the duration of the safe operation of hydraulic structures, reduces operating costs during the period of use and with a negative impact on the environment, and creates new information systems that allow managing hydraulic structures.

EVALUATING POTENTIAL FLOOD MITIGATION EFFECT OF PADDY FIELD DAM FOR TYPHOON NO. 19 IN 2019 IN THE NARUSE RIVER BASIN

In recent years, to mitigate the flood disaster caused by the increasing intensity and frequency of torrential rain events, some places have adjusted the retention of the paddy field by installing the runoff control device called paddy field dam. In comparison with other flood control facilities, the installation cost is much lower mainly for drainage control devices at the drain outlet of the paddy field, while the expected effect is significant since paddy fields are widely distributed in Japan. Therefore, this research aims to evaluate the potential flood mitigation effect of the paddy field dam for typhoon 19th in October 2019 in the Naruse River basin using the Rainfall-Runoff-Inundation model. To consider the potential effect of all paddy fields inside the basin, a simple one-dimensional paddy field dam model was developed, which can be applied for the whole basin. Moreover, the scenario analysis was conducted for different heights of free-drain and proportion of application. In conclusion, the paddy field could store about 90 million m3 water in whole paddy fields in the basin using 15 cm height of free-drain, and it significantly mitigated flood in the downstream of the Naruse River basin.

Comparison and Selection of Sewage Outlet of a Refining and Chemical Project Based on Mike21 Model

The Mike21 model is used to conduct a numerical simulation study on the setting plan of the warm water outlet of a refining and chemical project. After determining the environmental conditions, formulate key constraints. Through the parameter setting of the model, a hydrodynamic model is established, and numerical simulation of temperature and drainage under several combinations of different schemes is carried out. According to the prediction results of the model, the results under different emission conditions in winter and summer and under different environmental conditions can be compared and analyzed, combined with the requirements of environmental conditions, and optimized, thereby obtaining relatively optimized site selection conditions. Through the process of comparison and selection, the implementation method and application process of the Mike21 model for numerical simulation of warm drainage are proposed, and the application focus of the selection of the location of warm drainage outlets is summarized.

Gas barrier mechanism in non-ventilation excavation

Gas overruns and explosions often occur in coal mining. To deal with this problem, the spatial structure model of a new non-ventilation excavation system is constructed. Combined with the model, a simulation experiment is conducted and the variations in gas concentration in each area of the system with variations in the amount of gas emission, drainage, and nitrogen curtain outlet velocity are obtained. The effectiveness of the gas barrier by the combined action of the gas drainage and nitrogen curtain is verified. This study provides the experimental basis for solving the problem of gas overruns and explosions, and is of great significance for realizing safe, efficient, and rapid excavation.

Lessons from Assessing Uncertainty in Agricultural Water Supply Estimation for Sustainable Rice Production

Agricultural water supply (AWS) estimation is one of the first and fundamental steps of developing agricultural management plans, and its accuracy must have substantial impacts on the following decision-making processes. In modeling the AWS for paddy fields, it is still common to determine parameter values, such as infiltration rates and irrigation efficiency, solely based on literature and rough assumptions due to data limitations; however, the impact of parameter uncertainty on the estimation has not been fully discussed. In this context, a relative sensitivity index and the generalized likelihood uncertainty estimation (GLUE) method were applied to quantify the parameter sensitivity and uncertainty in an AWS simulation. A general continuity equation was employed to mathematically represent the paddy water balance, and its six parameters were investigated. The results show that the AWS estimates are sensitive to the irrigation efficiency, drainage outlet height, minimum ponding depth, and infiltration, with the irrigation efficiency appearing to be the most important parameter; thus, they should be carefully selected. Multiple combinations of parameter values were observed to provide similarly good predictions, and such equifinality produced the substantial amount of uncertainty in AWS estimates regardless of the modeling approaches, indicating that the uncertainty should be counted when developing water management plans. We also found that agricultural system simulations using only literature-based parameter values provided poor accuracy, which can lead to flawed decisions in the water resources planning processes, and then the inefficient use of public investment and resources. The results indicate that modelers’ careful parameter selection is required to improve the accuracy of modeling results and estimates from using not only information from the past studies but also modeling practices enhanced with local knowledge and experience.

Dynamic simulation of river water environmental capacity based on the subsection summation model.

There are noteworthy problems in current strategies to calculate river water environmental capacity (WEC), including the generalization of tributaries and water intakes, which results in inaccurate calculation results of the WEC, and the difficulty in adapting to dynamic changes in demands and hydrological conditions in terms of practical application. To address these flaws, the subsection summation model (SSM) was built for river WEC calculation. The SSM increases the number of control sections according to drain outlets, water intakes, and tributaries and acquires the WEC of the functional area section by section. The Wei River was taken as the study area for verification and application of the SSM. Supported by a comprehensive integration platform, the WEC simulation system of the Wei River was constructed. The results show that the SSM enhances the accuracy of the WEC calculation, and the results are closer to the actual situation. The simulation system could obtain the WEC according to the demands and changes in the hydrological conditions, thus providing technical means for policymakers. PRACTITIONER POINTS: The subsection summation model provides a more accurate water environmental capacity (WEC) calculation method considering tributaries and water intakes avoiding generalization. The simulation system should be established to make the WEC calculation adapt to the demands or changes in the hydrological conditions. The model and system could supply the basis and technical means for decision-making.

Hydrotransport-Oriented Zn, Cu, and Pb Behavior Assessment and Source Identification in the River Network of a Historically Mined Area in the Hokuroku Basin, Northeast Japan.

Aquatic ecosystems continuously receive potentially hazardous heavy metals from natural and anthropogenic sources. Focusing on the origin of heavy metals, this study aims to estimate the load contribution of tributaries from individual watershed and human drainage and to dissect the source of heavy metals, as commonly required for environmental impact assessment. Using integrated water dynamics, Geographic Information System (GIS), and chemical analysis, we identified and evaluated the heavy metal sources of the Kosaka river system in Hokuroku basin, which is a historically mined area in Northeast Japan, both in the high-water and low-water seasons. The migration and diffusion behaviors of heavy metals along with hydro-transport were analyzed, and the effects of mining activities on regional water quality both in the high-water and low-water seasons were clarified. The results indicate that Zn pollution was obvious in the Kosaka River network, especially in the downstream area. The spatial heterogeneity of heavy metal outflows from tributary watersheds was obvious, and the variations had strong correlations with mine site locations. The heavy metal flows in the mainstream increased sharply in the vicinity downstream of the Kosaka refinery drainage outlets. Compared to the low-water season, the influences of human drainage were slighter in high-water season, with lower contribution rates due to the dilution effect of the greater water discharge. Downscale sampling is effective to identify pollutant sources in regional basins.

Sustainable Water Management in Agriculture—The Impact of Drainage Water Management on Groundwater Table Dynamics and Subsurface Outflow

The paper presents the results of the effects of control drainage (CD) on the groundwater table and subsurface outflow in Central Poland. The hydrologic model DRAINMOD was used to simulate soil water balance with drain spacing of 7 and 14 m, different initial groundwater Table 40, 60 and 80 cm b.s.l., and dates at the beginning of control drainage of 1 March, 15 March, 1 April, and 15 April. The CD restricts flow at the drain outlet to maintain a water table during the growing season. Simulations were made for the periods from March to September for the years 2014, 2017, and 2018, which were average, wet, and dry, respectively. The simulations showed a significant influence of the initial groundwater tables and date blocking the outflow from the drainage network on the obtained results. In the conditions of central Poland, the use of CD is rational only when it is started between 1 and 15 March. In this case, the groundwater table can be increased from 10 to 33 cm (7 m spacing) and from 10 to 41 cm (14 m spacing) in relation to the conventional system (free drainage—FD). In the case of blocking the outflow on 1 March, the reduction is about 80% on average in the period from March to September. With a delay in blocking the outflow, the impact of CDs decreases and ranges from 8% to 50%. Studies have shown that the proper use of the drainage network infrastructure complies with the idea of sustainable development, as it allows efficient water management, by reduction of the outflow and, thus, nitrates from agricultural areas. Furthermore, CD solutions can contribute to mitigating the effects of climate change on agriculture by reducing drought and flood risk.

Occurrence, Input, and Seasonal Variations of Poly-and Perfluoroalkyl Substances (PFASs) in Rivers and Drain Outlets from the Dalian Coastal Area, China

Concentrations of 19 PFASs (poly-and perfluoroalkyl substances) in riverwater, coastal wastewater, and effluents from wastewater treatment plants (WWTPs) directly discharged into the Dalian coastal area were measured and their inputs were calculated accordingly. For riverwater samples, the total PFAS concentration ranged from 9.85 to 757 ng·L-1, with a median of 74.7 ng·L-1. For drain outlets, the total PFAS concentration in wastewater ranged from 9.19 to 801 ng·L-1, with a median of 29.5 ng·L-1. PFOS and PFOA were the dominant contributors for the PFASs in both riverwater and wastewater samples in this study. The total PFASs concentration in the industrial wastewater samples collected during the winter were found to be significantly higher than those collected in the summer. However, no seasonal variation was found for other samples. The total PFAS input into the Dalian coastal area was calculated to be 44.7 kg·a-1. The detection frequencies of Cl-PFESAs were low, and no 8:2Cl-PFESA was detected in all collected samples.

Assess Effectiveness of Salt Removal by a Subsurface Drainage with Bundled Crop Straws in Coastal Saline Soil Using HYDRUS-3D

The low permeability of soil and high investment of salt management pose great challenges for implementation of land reclamation in coastal areas. In this study, a temporary soil leaching system was tested in which bundled maize straw (straw drainage module, SDM) was operated as a subsurface drainage tube and diluted seawater was used for leaching. A preliminary field experiment was conducted in coastal soil-filled lysimeters to examine the system’s feasibility and a numerical model (HYDRUS-3D) based on field measured data was designed to simulate the entire leaching process. The simulation results showed that the soil water velocity and the non-uniformity of salt distribution were apparently enhanced in the region approaching the drain outlet. The mass balance information indicated that the amount of water drained with SDM accounts for 37.9–66.0% of the total amount of leaching water, and the mass of salt removal was about 1.7 times that of the salt input from the diluted seawater. Additional simulations were conducted to explore the impacts of the design parameters, including leaching amount, the salinity of leaching water, and the number of leaching events on the desalination performance of the leaching system. Such simulations showed that the salt removal efficiency and soil desalination rate both were negatively related to the seawater mixture rate but were positively associated with the amount of leaching water. Increasing the leaching times, the salt removal efficiency was gradually decreased in all treatments, but the soil desalination rate was decreased only in the treatments leached with less diluted seawater. Our results confirmed the feasibility of the SDM leaching system in soil desalination and lay a good foundation for this system application in initial reclamation of saline coastal land.

Effects of Sediment Released from a Check Dam on Sediment Deposits and Fish and Macroinvertebrate Communities in a Small Stream

Dam removal is typically intended for river restoration or as a countermeasure for aging dams. The influence of dam removal has mainly been studied in large rivers. This study is intended to investigate the influence of the sediment supplied after opening a check dam drain in a small steep stream to contribute to the establishment of sediment release technology form check dam by accumulating the basic knowledge about the influence of sediment release. Deposited sediment in the impoundment was rapidly discharged immediately after opening the drain outlet, and a moderate sediment discharge followed. The water course of the sediments deposited by repeated channel widening and riverbed degradation tended to stop longitudinal topographic changes from downstream. In addition, the turbidity during a flood was high in the first year and tended to decrease in the second year. As for the ecosystem response, changes in the benthic macroinvertebrate community were confirmed in downstream sites, and net-spinning species especially deceased immediately after the sediment supply began. Our monitoring results suggest that the increasing turbidity was suppressed during the flood because sediment release was conducted from the small-scale facility. As a result, a negative impact on the aquatic ecosystem seemed to be reduced.

Elevated phosphate, ammonia and total suspended solids near sewage outlets and reclamation sites in coastal waters of Makassar, Indonesia

Makassar is a large city in Southeast Asia with a strategic role to play in supporting the development of Indonesia. Its position as a centre for local and regional development has led to a sharp increase in the human population and a concomitant need for supporting facilities. With limited land in coastal areas, reclamation is one option being implemented. The increases in population and reclamation have both had negative effects on the condition of coastal waters. This study aimed to compare the levels of phosphate, ammonia and TSS in the waters near selected drainage outlets of Makassar City before and after land reclamation. The results showed increasingly high levels of phosphate at two sites (Jongaya and Paotere Canals). Increased ammonia, nitrogen and TSS were only found at the outlet of the Jongaya Canal. Four of the outlets (Jeneberang River, Benteng Canal and Tallo River) had relatively low nutrient concentrations. The results indicate that domestic waste is a major source of phosphate and ammonia pollution in the Jongaya and Paotere Canals. In the Jongaya Canal, all parameters (phosphate, ammonia, nitrogen, and TSS) were higher after the reclamation than beforehand

Effect of controlled drainage on nitrogen fate and transport for a subsurface drained grass field receiving liquid swine lagoon effluent

Application of livestock manure has become a principal nutrient source in groundwater and surface water. The goal of this research was to investigate the effect of controlled drainage (CD) on nitrogen (N) fate and transport for a subsurface drained grass field receiving liquid swine lagoon effluent (SLE). A four-year field experiment was conducted on a naturally poorly drained pasture in eastern North Carolina. The 1.25 ha experimental field was artificially drained by subsurface drains installed at 1.0 m depth and 12.5 m spacing. Two treatments, replicated twice were implemented: conventional drainage (FD) and CD. The CD management protocol was more intensive compared to previous studies. The drain outlets of CD plot were set at 36 cm below soil surface all year round except several days before irrigation application when water table depth was shallower than 65 cm below surface. Controlled drainage significantly reduced drainage flow and TN loading via subsurface drain lines by an average of 397 mm yr−1 (93%) and 34.5 kg N ha−1 yr−1 (94%), respectively. DRAINMOD hydrologic simulations indicated that 96% of the reduction in predicted drain flow was attributed to increased lateral seepage. The nitrogen that did not drain from the field in response to CD was lost via enhanced denitrification (67%) and lateral seepage to adjacent fields (33%). This study clearly demonstrated how CD management affects the N fate and transport through seepage and denitrification process.

Passive Dosing of Organic Substrates for Nitrate-Removing Bioreactors Applied in Field Margins.

Denitrifying bioreactors are dependent on organic matter supply as a substrate for effective NO removal. In this study, the difference in removal efficiency and side effects when using different organic matter sources and dosing strategies was tested in two field experiments. The organic matter sources tested were woodchips and ethanol. The effect of woodchips was tested using woodchip-enveloped drains. Ethanol was supplied to a flow-through reactor by passive dosing by diffusion through silicone tubing. The woodchip-enveloped drains showed a removal efficiency of 80% during the first year of application, but this rate decreased during the second and third years of application, coinciding with a decrease in dissolved organic C and an increase in redox potential. The removal efficiency was higher and remained higher over a longer period of time when the drains were installed more deeply. The flow-through reactor with ethanol could lead to a higher removal efficiency (up to 95%) at higher hydraulic retention time (HRT, 0.1 d) than the woodchip-enveloped drains (HRT = 5 d). Passive dosing of organic substrates is simple, needs little maintenance and no energy, and can be performed independent of electricity. A denitrifying bioreactor with a controlled drainage inlet and outlet is a promising setup for optimizing N removal and minimizing side effects.

Phosphate removal by iron oxide-coated diatomite: Laboratory test of a new method for cleaning drainage water

Transport of phosphate (P) in drainage water from P rich agricultural fields to freshwaters via drains may cause open water eutrophication. One way to reduce this transport is by installation of P sorbing filters at drain outlets. As drainage water flows and P concentrations can be highly fluctuating, suitable filters must have good hydraulic conductivity and high P sorbing efficiency, i.e. rapid sorption with high affinity and capacity. To fulfill these requirements, we tested a new concept for filter material design comprising porous and stable calcined diatomaceous earth particles (CDE, 2–4 mm) coated with thin layers of high affinity P sorbing amorphous iron oxide. According to NMR and MICP analyses the material had a bimodal pore size distribution with average diameters of around 1 μm and 100 μm. The coating formed a thin film on the CDE internal and external surfaces and markedly increased the P sorption efficiency. Thus, P in 0.1 and 0.5 mg P/L solutions was almost quantitatively sorbed within 1½ min at a solution:solid ratio of 100. SEM-EDX demonstrated that P quickly penetrated into the porous structure of the CDE granules and that all Fe in the coating was active in P bonding. This conceptual investigation demonstrates that porous CDE is a useful host into which Fe oxides can be precipitated resulting in an effective P sorbing material.

Simulation of Flow and Agricultural Non-Point Source Pollutant Transport in a Tibetan Plateau Irrigation District

Flow and transport processes in soil and rock play a critical role in agricultural non-point source pollution (ANPS) loads. In this study, we investigated the ANPS load discharged into rivers from an irrigation district in the Tibetan Plateau and simulated ANPS load using a distributed model. Experiments were conducted for two years to measure soil water content and nitrogen concentrations in soil and the quality and quantity of subsurface lateral flow in the rock and at the drainage canal outlet during the highland barley growing period. A distributed model, in which the subsurface lateral flow in the rock was described using a stepwise method, was developed to simulate flow and ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) transport processes. Sobol’s method was used to evaluate the sensitivity of simulated flow and transport processes to the model inputs. The results showed that with a 21.2% increase of rainfall and irrigation in the highland barley growing period, the average NH4+-N and NO3−-N concentrations in the soil layer decreased by 10.8% and 14.3%, respectively, due to increased deep seepage. Deep seepage of rainfall water accounted for 0–52.4% of total rainfall, whereas deep seepage of irrigation water accounted for 36.6–45.3% of total irrigation. NH4+-N and NO3−-N discharged into the drainage canal represented 19.9–30.4% and 19.4–26.7% of the deep seepage, respectively. The mean Nash–Sutcliffe coefficient value, which was close to 0.8, and the lowest values of root mean square errors, the fraction bias, and the fractional gross error indicated that the simulated flow rates and nitrogen concentrations using the proposed method were very accurate. The Sobol’s sensitivity analysis results demonstrated that subsurface lateral flow had the most important first-order and total-order effect on the simulated flow and NH4+-N and NO3−-N concentrations at the surface drainage outlet.

Locating tile drainage outlets and surface flow in riparian lowlands using thermal infrared and RGB-NIR remote sensing

ABSTRACTArtificial drainage of agricultural fields represents a major flow path way of both water and nutrients which may contribute to eutrophication issues in the recipient waters. Several studies have shown that riparian lowlands (alluvial plains, wetlands, meadows), if present, may act as buffer zones with high nutrient retention capacities. To assess the fate of water and nutrient flow in riparian lowlands in tile drained catchments, it is essential to know the locations of tile drainage outlets as sources of nutrient input. Using a thermal infrared (TIR) remote-sensing survey, we identified potential tile drainage outlets in a riparian lowland. We also applied a normalized differentiated vegetation index (NDVI) approach to illustrate how tile drainage outlets can be identified with free broadband RGB-NIR data. The positions of identified outlets were validated in the field by visual observation. Our study finds that TIR remote sensing is a strong tool when assessing the sources of water input. NDVI is also applicable, however the background values are very variable making the outlets difficult to locate. The results can be applied in studies of water movement and solute transport via tile drainage as well as model studies where knowledge of input areas through tile drainage is of great importance.

Enhancing Groundwater Recharge with Sand Ditches

Abstract. Localized and artificial groundwater recharge is an important water management strategy in arid regions. However, artificial recharge is limited by the hydraulic characteristics of surface soil which control downward water percolation to the aquifers. In heavy soils with low infiltration and hydraulic conductivity rate, water percolation can be enhanced by constructing deep ditches filled with highly permeable materials, such as sand. Laboratory experiments were conducted to examine the effect of constructing a deep sand ditch across the slope of a soil box (50 × 20 × 25 cm3) on runoff and deep percolation to the drainage outlet of the soil box. A sandy loam soil packed in two bulk densities (1200 and 1500 kg/m3) was used for the experiments. The experiments were carried out using simulated steady runoff of about 300 mL/min for a duration of 60 min. Experimental results showed that sand ditches greatly enhanced water deep percolation in soils but their relative effect was more profound in compacted high-density soil compared to soil having low-density. The drainage water collected from compacted soil boxes in the presence of sand ditches increased by 10 times compared to control soil without sand ditches. In the case of low-density soil, the presence of sand ditches eliminated the runoff but the increase in drainage water was about 18% compared to control. The experimental results clearly revealed that creating high infiltration zones within the soil matrix, such as sand ditches, significantly increased water deep percolation and herewith groundwater recharge in drylands, especially in heavy soils. Keywords: Arid regions, Groundwater recharge, Percolation, Rapid infiltration.