The rise in smart water technologies has introduced new cybersecurity vulnerabilities for water infrastructures. However, the implications of cyber-physical attacks on the systems like urban drainage systems remain underexplored. This research delves into this gap, introducing a method to quantify flood risks in the face of cyber-physical threats. We apply this approach to a smart stormwater system—a real-time controlled network of pond-conduit configurations, fitted with water level detectors and gate regulators. Our focus is on a specific cyber-physical threat: false data injection (FDI). In FDI attacks, adversaries introduce deceptive data that mimics legitimate system noises, evading detection. Our risk assessment incorporates factors like sensor noises and weather prediction uncertainties. Findings reveal that FDIs can amplify flood risks by feeding the control system false data, leading to erroneous outflow directives. Notably, FDI attacks can reshape flood risk dynamics across different storm intensities, accentuating flood risks during less severe but more frequent storms. This study offers valuable insights for strategizing investments in smart stormwater systems, keeping cyber-physical threats in perspective. Furthermore, our risk quantification method can be extended to other water system networks, such as irrigation channels and multi-reservoir systems, aiding in cyber-defense planning.
{"title":"Flood Risks of Cyber-Physical Attacks in a Smart Storm Water System","authors":"Chung-Yi Lin, Yi-Chen Ethan Yang, Faegheh Moazeni","doi":"10.1029/2023wr034827","DOIUrl":"https://doi.org/10.1029/2023wr034827","url":null,"abstract":"The rise in smart water technologies has introduced new cybersecurity vulnerabilities for water infrastructures. However, the implications of cyber-physical attacks on the systems like urban drainage systems remain underexplored. This research delves into this gap, introducing a method to quantify flood risks in the face of cyber-physical threats. We apply this approach to a smart stormwater system—a real-time controlled network of pond-conduit configurations, fitted with water level detectors and gate regulators. Our focus is on a specific cyber-physical threat: false data injection (FDI). In FDI attacks, adversaries introduce deceptive data that mimics legitimate system noises, evading detection. Our risk assessment incorporates factors like sensor noises and weather prediction uncertainties. Findings reveal that FDIs can amplify flood risks by feeding the control system false data, leading to erroneous outflow directives. Notably, FDI attacks can reshape flood risk dynamics across different storm intensities, accentuating flood risks during less severe but more frequent storms. This study offers valuable insights for strategizing investments in smart stormwater systems, keeping cyber-physical threats in perspective. Furthermore, our risk quantification method can be extended to other water system networks, such as irrigation channels and multi-reservoir systems, aiding in cyber-defense planning.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"71 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139091306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuanning Zhang, Xueping Gao, Bowen Sun, Xiaobo Liu
Benthic oxygen flux with complex spatiotemporal variations is essential for the global budget of carbon dioxide and the regional security of water quality and ecology, but its dominant driver under different circumstances has yet to be identified. In this study, a parametric scheme of oxygen flux was proposed and validated with aquatic eddy correlation measurements and then coupled with a diagenesis model and a water environment model. The coupled model was applied to a river-reservoir with significant environmental gradients in hydrodynamics, diagenesis, and hypoxia, which are three factors that competitively drive the variation in benthic oxygen flux. The results indicate that hydrodynamics dominate the flux in the riverine and thalweg areas, diagenesis is the dominant driver of the lacustrine and bank areas, and hypoxia shows dominance only in the hypolimnetic anoxic area. In general, diagenesis is the dominant driver of oxygen flux in river-reservoirs, followed by hydrodynamics, both of which are more prominent than hypoxia. If the operated reservoir experiences a wet year, the dominance of hydrodynamics tends to increase, while that of diagenesis and hypoxia decreases. The three divers exhibit similar but more stable dominance in riverine systems than in reservoirs, while diagenesis becomes the exclusive driver of oxygen fluxes in lacustrine systems.
{"title":"Hydrodynamics, Diagenesis and Hypoxia Variably Drive Benthic Oxygen Flux in a River-Reservoir System","authors":"Yuanning Zhang, Xueping Gao, Bowen Sun, Xiaobo Liu","doi":"10.1029/2023wr035449","DOIUrl":"https://doi.org/10.1029/2023wr035449","url":null,"abstract":"Benthic oxygen flux with complex spatiotemporal variations is essential for the global budget of carbon dioxide and the regional security of water quality and ecology, but its dominant driver under different circumstances has yet to be identified. In this study, a parametric scheme of oxygen flux was proposed and validated with aquatic eddy correlation measurements and then coupled with a diagenesis model and a water environment model. The coupled model was applied to a river-reservoir with significant environmental gradients in hydrodynamics, diagenesis, and hypoxia, which are three factors that competitively drive the variation in benthic oxygen flux. The results indicate that hydrodynamics dominate the flux in the riverine and thalweg areas, diagenesis is the dominant driver of the lacustrine and bank areas, and hypoxia shows dominance only in the hypolimnetic anoxic area. In general, diagenesis is the dominant driver of oxygen flux in river-reservoirs, followed by hydrodynamics, both of which are more prominent than hypoxia. If the operated reservoir experiences a wet year, the dominance of hydrodynamics tends to increase, while that of diagenesis and hypoxia decreases. The three divers exhibit similar but more stable dominance in riverine systems than in reservoirs, while diagenesis becomes the exclusive driver of oxygen fluxes in lacustrine systems.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"10 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139091204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Colloidal contaminants infiltrate and can be attached onto grain surfaces of soils and aquifers, where they may persist. In this study, Lagrangian particle tracking is used to investigate particle trajectories and attachment in pore and fracture spaces modeled as three-dimensional constricted tubes with diverse geometries and orientations relative to gravity. A comprehensive force balance arising from hydrodynamic drag and lift, gravitational settling, Brownian motion, and attractive DLVO interactions is simulated. Results show that the collection efficiency η is primarily governed by the dimensionless settling number 𝑆, representing the relative dominance of gravitational over hydrodynamic forces experienced by the particles. High-𝑆 scenarios have larger η and are more sensitive to pore orientation, while low-𝑆 scenarios are more sensitive to pore geometry. For all scenarios but especially low-S scenarios, the majority of colloid attachment occurs near pore extremities, where fluid velocities are low, such that mechanical remobilization of particles attached is improbable. In low-𝑆 scenarios, particles may spread and become immobilized at greater distances from the contamination source owing to lower η, are harder to mechanically remobilize as they attach more disproportionately at pore extremities, and have trajectories more sensitive to minor forces, rendering their environmental fates complex. Characterizing the collection efficiency and deposition morphology for various pore space geometries and orientations is crucial in understanding particle fate and developing continuum-scale models of colloid transport in real soils, where pore spaces are heterogeneous and advection paths are tortuous.
胶体污染物会渗入并附着在土壤和含水层的颗粒表面，并可能在那里持续存在。本研究采用拉格朗日粒子追踪技术研究粒子在孔隙和断裂空间中的运动轨迹和附着情况，孔隙和断裂空间被模拟为具有不同几何形状和相对于重力方向的三维收缩管。模拟了由流体动力阻力和升力、重力沉降、布朗运动和有吸引力的 DLVO 相互作用引起的综合力平衡。结果表明，收集效率η主要受无量纲沉降数𝑆的影响，该数代表粒子所受重力相对于流体动力的主导地位。高𝑆方案的η较大，对孔隙取向更敏感，而低𝑆方案对孔隙几何形状更敏感。在所有情况下，尤其是低 S 情况下，大部分胶体附着都发生在孔隙末端附近，那里的流体速度较低，因此附着的颗粒不可能机械地重新移动。在低𝑆情景下，由于η较低，颗粒可能会在距离污染源更远的地方扩散和固定，由于它们更多地附着在孔隙末端，因此更难机械地再固定，而且其轨迹对微小的力更敏感，从而使其环境命运变得复杂。在实际土壤中，孔隙空间是异质的，吸附路径是曲折的，因此要了解颗粒的归宿，并建立胶体在土壤中的连续尺度迁移模型，就必须确定各种孔隙空间几何形状和方向的收集效率和沉积形态。
{"title":"Colloid Transport and Retention in Constricted Tube Pore Spaces With Diverse Geometries and Orientations","authors":"Darrell Tang, Amir Raoof","doi":"10.1029/2023wr035456","DOIUrl":"https://doi.org/10.1029/2023wr035456","url":null,"abstract":"Colloidal contaminants infiltrate and can be attached onto grain surfaces of soils and aquifers, where they may persist. In this study, Lagrangian particle tracking is used to investigate particle trajectories and attachment in pore and fracture spaces modeled as three-dimensional constricted tubes with diverse geometries and orientations relative to gravity. A comprehensive force balance arising from hydrodynamic drag and lift, gravitational settling, Brownian motion, and attractive DLVO interactions is simulated. Results show that the collection efficiency <i>η</i> is primarily governed by the dimensionless settling number 𝑆, representing the relative dominance of gravitational over hydrodynamic forces experienced by the particles. High-𝑆 scenarios have larger <i>η</i> and are more sensitive to pore orientation, while low-𝑆 scenarios are more sensitive to pore geometry. For all scenarios but especially low-<i>S</i> scenarios, the majority of colloid attachment occurs near pore extremities, where fluid velocities are low, such that mechanical remobilization of particles attached is improbable. In low-𝑆 scenarios, particles may spread and become immobilized at greater distances from the contamination source owing to lower <i>η</i>, are harder to mechanically remobilize as they attach more disproportionately at pore extremities, and have trajectories more sensitive to minor forces, rendering their environmental fates complex. Characterizing the collection efficiency and deposition morphology for various pore space geometries and orientations is crucial in understanding particle fate and developing continuum-scale models of colloid transport in real soils, where pore spaces are heterogeneous and advection paths are tortuous.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"34 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139076899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David A. Peterson, Stephanie K. Kampf, Kira C. Puntenney-Desmond, Matthew P. Fairchild, Sam Zipper, John C. Hammond, Matthew R. V. Ross, Megan G. Sears
Streamflow duration is important for aquatic ecosystems and assigning stream protection status. This study predicts streamflow duration, represented as the fraction of time with flow each year, using a combination of sensor data and crowd-sourced visual observations for a study area in northern Colorado, USA. We used 11 stream stage sensors and 177 visual monitoring points to examine how frequently streams should be sampled to compute flow fractions accurately. This showed that the number of visual observations needed to compute accurate flow fractions increases with decreasing flow duration. We then developed random forest models to predict mean annual flow fractions using climate, topographic, and land cover predictors and found that snow persistence, summer precipitation, and drainage area were important predictors. Model performance was best when using sites with ≥10 visual observations. Our model predicts that almost all (98%) of streams in the study region are non-perennial, about 10% more than the amount of non-perennial streams in the National Hydrography Dataset. Stream type maps are sensitive to the time period of data collection and to thresholds used to represent perennial versus non-perennial flow. To improve maps of non-perennial streams, we recommend moving beyond categorical classification of streams to a continuous variable like flow fraction. These efforts can be best supported with frequent observations in time that span streams with a wide range of flow fractions and drainage area attributes.
{"title":"Predicting Streamflow Duration From Crowd-Sourced Flow Observations","authors":"David A. Peterson, Stephanie K. Kampf, Kira C. Puntenney-Desmond, Matthew P. Fairchild, Sam Zipper, John C. Hammond, Matthew R. V. Ross, Megan G. Sears","doi":"10.1029/2023wr035093","DOIUrl":"https://doi.org/10.1029/2023wr035093","url":null,"abstract":"Streamflow duration is important for aquatic ecosystems and assigning stream protection status. This study predicts streamflow duration, represented as the fraction of time with flow each year, using a combination of sensor data and crowd-sourced visual observations for a study area in northern Colorado, USA. We used 11 stream stage sensors and 177 visual monitoring points to examine how frequently streams should be sampled to compute flow fractions accurately. This showed that the number of visual observations needed to compute accurate flow fractions increases with decreasing flow duration. We then developed random forest models to predict mean annual flow fractions using climate, topographic, and land cover predictors and found that snow persistence, summer precipitation, and drainage area were important predictors. Model performance was best when using sites with ≥10 visual observations. Our model predicts that almost all (98%) of streams in the study region are non-perennial, about 10% more than the amount of non-perennial streams in the National Hydrography Dataset. Stream type maps are sensitive to the time period of data collection and to thresholds used to represent perennial versus non-perennial flow. To improve maps of non-perennial streams, we recommend moving beyond categorical classification of streams to a continuous variable like flow fraction. These efforts can be best supported with frequent observations in time that span streams with a wide range of flow fractions and drainage area attributes.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"100 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139076894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peizhen Ren, Michael Stewardson, Murray Peel, Margot Turner, Andrew John
Future water availability is threatened by changes in both climate and water demand. Water rights with differing priorities are an important foundation of demand-side tools (e.g., buyback, water pricing, and water market) to improve water use efficiency and reduce water scarcity, especially in highly regulated river systems. This paper assesses the impact of climate change on water yields from carryover storage with dual-priority (high/low) water rights allocation systems using a simple and rapid analytical method. The method characterizes reservoir inflows using readily available flow characteristics (annual mean and Cv). We evaluate this method against a water resource simulation model in the Goulburn River basin, Australia. In general, our analytical “dual-priority” Gould-Dincer model reproduces water allocation estimates from the simulation model. We further demonstrate this method across 12 Australian catchments to investigate the climate change impact on “dual-priority” water rights yield at the catchment scale. The hydrological projections show decreasing mean annual runoff and increasing annual runoff variability, except for some catchments in northern Australia. Water yield for high-priority water rights (HPWRs) and low-priority water rights (LPWRs) decreases for most catchments except for some catchments in northern Australia. South Dandalup in the 2070s (RCP8.5) shows the largest percentage decrease in HPWR and LPWR yield (about −53.53% and −56.81%, respectively). Our results show that changes in mean annual inflow have a more significant influence on water yield of HPWR and LPWR than Cv. Overall, the simple method provides a rapid assessment of water yields with “dual-priority” water rights which is applicable across multiple sites at regional or even global scale.
{"title":"Assessing Climate Change Impacts on Yield of “Dual-Priority” Water Rights in Carryover Systems at Catchment Scale","authors":"Peizhen Ren, Michael Stewardson, Murray Peel, Margot Turner, Andrew John","doi":"10.1029/2023wr035376","DOIUrl":"https://doi.org/10.1029/2023wr035376","url":null,"abstract":"Future water availability is threatened by changes in both climate and water demand. Water rights with differing priorities are an important foundation of demand-side tools (e.g., buyback, water pricing, and water market) to improve water use efficiency and reduce water scarcity, especially in highly regulated river systems. This paper assesses the impact of climate change on water yields from carryover storage with dual-priority (high/low) water rights allocation systems using a simple and rapid analytical method. The method characterizes reservoir inflows using readily available flow characteristics (annual mean and <i>C</i><sub><i>v</i></sub>). We evaluate this method against a water resource simulation model in the Goulburn River basin, Australia. In general, our analytical “dual-priority” Gould-Dincer model reproduces water allocation estimates from the simulation model. We further demonstrate this method across 12 Australian catchments to investigate the climate change impact on “dual-priority” water rights yield at the catchment scale. The hydrological projections show decreasing mean annual runoff and increasing annual runoff variability, except for some catchments in northern Australia. Water yield for high-priority water rights (HPWRs) and low-priority water rights (LPWRs) decreases for most catchments except for some catchments in northern Australia. South Dandalup in the 2070s (RCP8.5) shows the largest percentage decrease in HPWR and LPWR yield (about −53.53% and −56.81%, respectively). Our results show that changes in mean annual inflow have a more significant influence on water yield of HPWR and LPWR than <i>C</i><sub><i>v</i></sub>. Overall, the simple method provides a rapid assessment of water yields with “dual-priority” water rights which is applicable across multiple sites at regional or even global scale.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"11 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139076917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Logan J. Swenson, Sam Zipper, Delaney M. Peterson, C. Nathan Jones, Amy J. Burgin, Erin Seybold, Matthew F. Kirk, Camden Hatley
Non-perennial streams, which lack year-round flow, are widespread globally. Identifying the sources of water that sustain flow in non-perennial streams is necessary to understand their potential impacts on downstream water resources, and guide water policy and management. Here, we used water isotopes (δ18O and δ2H) and two different modeling approaches to investigate the spatiotemporal dynamics of young water fractions (Fyw) in a non-perennial stream network at Konza Prairie (KS, USA) during the 2021 summer dry-down season, as well as over several years with varying hydrometeorological conditions. Using a Bayesian model, we found a substantial amount of young water (Fyw: 39.1–62.6%) sustained flows in the headwaters and at the catchment outlet during the 2021 water year, while 2015–2022 young water contributions estimated using sinusoidal models indicated smaller Fyw amounts (15.3% ± 5.7). Both modeling approaches indicate young water releases are highly sensitive to hydrological conditions, with stream water shifting to older sources as the network dries. The shift in water age suggests a shift away from rapid fracture flow toward slower matrix flow that creates a sustained but localized surface water presence during late summer and is reflected in the annual dynamics of water age at the catchment outlet. The substantial proportion of young water highlights the vulnerability of non-perennial streams to short-term hydroclimatic change, while the late summer shift to older water reveals a sensitivity to longer-term changes in groundwater dynamics. Combined, this suggests that local changes may propagate through non-perennial stream networks to influence downstream water availability and quality.
{"title":"Changes in Water Age During Dry-Down of a Non-Perennial Stream","authors":"Logan J. Swenson, Sam Zipper, Delaney M. Peterson, C. Nathan Jones, Amy J. Burgin, Erin Seybold, Matthew F. Kirk, Camden Hatley","doi":"10.1029/2023wr034623","DOIUrl":"https://doi.org/10.1029/2023wr034623","url":null,"abstract":"Non-perennial streams, which lack year-round flow, are widespread globally. Identifying the sources of water that sustain flow in non-perennial streams is necessary to understand their potential impacts on downstream water resources, and guide water policy and management. Here, we used water isotopes (δ<sup>18</sup>O and δ<sup>2</sup>H) and two different modeling approaches to investigate the spatiotemporal dynamics of young water fractions (<i>F</i><sub><i>yw</i></sub>) in a non-perennial stream network at Konza Prairie (KS, USA) during the 2021 summer dry-down season, as well as over several years with varying hydrometeorological conditions. Using a Bayesian model, we found a substantial amount of young water (<i>F</i><sub><i>yw</i></sub>: 39.1–62.6%) sustained flows in the headwaters and at the catchment outlet during the 2021 water year, while 2015–2022 young water contributions estimated using sinusoidal models indicated smaller <i>F</i><sub><i>yw</i></sub> amounts (15.3% ± 5.7). Both modeling approaches indicate young water releases are highly sensitive to hydrological conditions, with stream water shifting to older sources as the network dries. The shift in water age suggests a shift away from rapid fracture flow toward slower matrix flow that creates a sustained but localized surface water presence during late summer and is reflected in the annual dynamics of water age at the catchment outlet. The substantial proportion of young water highlights the vulnerability of non-perennial streams to short-term hydroclimatic change, while the late summer shift to older water reveals a sensitivity to longer-term changes in groundwater dynamics. Combined, this suggests that local changes may propagate through non-perennial stream networks to influence downstream water availability and quality.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"85 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139076888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. I. de Lange, D. Sehgal, N. Martínez-Carreras, K. Waldschläger, V. Bense, C. Hissler, A. J. F. Hoitink
Accurate particle size distribution (PSD) measurements of suspended particulate matter (SPM) composed of flocs and aggregates are important to improve understanding of ecological and geomorphological processes, and for environmental engineering applications. PSDs can be measured in situ (in the field) using a submersible sensor, or ex situ (in the laboratory) using samples. The methodological choice is often guided by logistical factors, and the differences in PSDs acquired by in situ and ex situ measurements is of concern. In this study, a laser-diffraction instrument (the LISST-200X) was used to compare in situ and ex situ PSD measurements. Samples measured ex situ were stored for three consecutive weeks and measured each week in a laboratory using different stirrer speeds. We observed that ex situ measurements display a higher D50 (median particle size) than in situ measurements of the same sample (up to 613% larger, 112% on average). Our experiments show that the difference between in situ and ex situ measurements can be explained by flocculation of the riverine sediments during the first week of storage. During the subsequent ex situ measurements, the stirring results in a significantly lower D50. Ex situ measurements are therefore unsuitable for flocculated SPM. This study provides recommendations for optimizing PSD measurements by calculating the measurement times required to obtain robust PSD measurements (exceeding 3 min per sample), which are larger for field samples with coarser particles and wider PSDs.
{"title":"The Impact of Flocculation on In Situ and Ex Situ Particle Size Measurements by Laser Diffraction","authors":"S. I. de Lange, D. Sehgal, N. Martínez-Carreras, K. Waldschläger, V. Bense, C. Hissler, A. J. F. Hoitink","doi":"10.1029/2023wr035176","DOIUrl":"https://doi.org/10.1029/2023wr035176","url":null,"abstract":"Accurate particle size distribution (PSD) measurements of suspended particulate matter (SPM) composed of flocs and aggregates are important to improve understanding of ecological and geomorphological processes, and for environmental engineering applications. PSDs can be measured in situ (in the field) using a submersible sensor, or ex situ (in the laboratory) using samples. The methodological choice is often guided by logistical factors, and the differences in PSDs acquired by in situ and ex situ measurements is of concern. In this study, a laser-diffraction instrument (the LISST-200X) was used to compare in situ and ex situ PSD measurements. Samples measured ex situ were stored for three consecutive weeks and measured each week in a laboratory using different stirrer speeds. We observed that ex situ measurements display a higher <i>D</i><sub>50</sub> (median particle size) than in situ measurements of the same sample (up to 613% larger, 112% on average). Our experiments show that the difference between in situ and ex situ measurements can be explained by flocculation of the riverine sediments during the first week of storage. During the subsequent ex situ measurements, the stirring results in a significantly lower <i>D</i><sub>50</sub>. Ex situ measurements are therefore unsuitable for flocculated SPM. This study provides recommendations for optimizing PSD measurements by calculating the measurement times required to obtain robust PSD measurements (exceeding 3 min per sample), which are larger for field samples with coarser particles and wider PSDs.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"97 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139061094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It remains an open question how the hydrodynamics and morphology in sharp meander bends adapt to the changes in flow and sediment conditions induced by upstream damming. This study reports a comprehensive investigation into the morphological changes, patterns of mean and secondary flows and sediment transport around two consecutive sharp bends in the Middle Yangtze River (MYR), and explains these changes from the viewpoint of flow-sediment transport-morphology interaction based on field measurements. With the Three Gorges Project operation, the MYR suffered a remarkable channel degradation due to a sudden decrease of incoming sediment discharge. The point bars were removed, and outer-bank benches (OBB) formed upstream of the bend apices, which resulted in quite different flow and sediment transport patterns in the bends. The highest velocity zones and center-region cells of secondary flow were more toward the inner bank due to the lack of point bars, and the outward migration of momentum was delayed. Flow recirculation zones were observed over the OBBs, covering 12%–58% of the channel width. The transport rates of suspended load accounted for 98% of the total sediment load, and the outward shift of the highest transport rate zone was confined by the OBBs, which reduced the effective width of sediment transport. These changes in flow and sediment transport re-inforced the morphological changes around the sharp bends: the velocity redistribution and evolution of scour factor lagged more behind planform curvature, which further promoted the erosion of point bars and the development of OBB.
{"title":"Hydrodynamic and Morphological Adaptation of Two Consecutive Sharp Bends of the Middle Yangtze River to Upstream Damming","authors":"Xin Liu, Junqiang Xia, Shanshan Deng, Meirong Zhou, Beiping Mao, Koen Blanckaert","doi":"10.1029/2023wr034990","DOIUrl":"https://doi.org/10.1029/2023wr034990","url":null,"abstract":"It remains an open question how the hydrodynamics and morphology in sharp meander bends adapt to the changes in flow and sediment conditions induced by upstream damming. This study reports a comprehensive investigation into the morphological changes, patterns of mean and secondary flows and sediment transport around two consecutive sharp bends in the Middle Yangtze River (MYR), and explains these changes from the viewpoint of flow-sediment transport-morphology interaction based on field measurements. With the Three Gorges Project operation, the MYR suffered a remarkable channel degradation due to a sudden decrease of incoming sediment discharge. The point bars were removed, and outer-bank benches (OBB) formed upstream of the bend apices, which resulted in quite different flow and sediment transport patterns in the bends. The highest velocity zones and center-region cells of secondary flow were more toward the inner bank due to the lack of point bars, and the outward migration of momentum was delayed. Flow recirculation zones were observed over the OBBs, covering 12%–58% of the channel width. The transport rates of suspended load accounted for 98% of the total sediment load, and the outward shift of the highest transport rate zone was confined by the OBBs, which reduced the effective width of sediment transport. These changes in flow and sediment transport re-inforced the morphological changes around the sharp bends: the velocity redistribution and evolution of scour factor lagged more behind planform curvature, which further promoted the erosion of point bars and the development of OBB.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"605 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139076915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oral Yagci, V. S. Özgur Kirca, Vasileios Kitsikoudis, Catherine A. M. E. Wilson, M. Furkan Celik, Caner Sertkan
Flume experiments were conducted to comprehend the impact of different patterns of an emergent vegetation patch on the flow field and the scour process in natural rivers. Velocity measurements, flow visualization, and scour tests were undertaken around different vegetation patch patterns, which were simulated inspired by the expansion process of a typical instream vegetation. The patch expansion process was idealized with an initially circular patch of rigid emergent stems becoming elongated due to positive and negative feedbacks. The expansion of the vegetation patch was considered to occur in three stages, in which the density of the patch from the previous stage was increased while the patch was also elongated by connecting at its downstream side with another sparser vegetation patch. These stages were replicated succesively by increasing the density and elongating the patch. In this way, two processes (i.e., elongation and decrease in permeability), which usually have hydrodynamically opposite effects on flow fields, were simulated at the same obstruction. Despite generally elongated obstacles being streamlined bodies, the morphometric analysis obtained by laser scanner revealed that streamlined elongation of permeable patches amplifies global scour and enhances localization of the local scour hole. This situation implies that as the patch expands, in the wake region, the steady-wake region becomes shorter, turbulence diminishes, lateral shear stress enhances, and deposition cannot occur far from the patch. Consequently, as the patch expands, the hydrodynamic consequences may restrict further patch expansion after a certain length/density.
{"title":"Experimental Study on Influence of Different Patterns of an Emergent Vegetation Patch on the Flow Field and Scour/Deposition Processes in the Wake Region","authors":"Oral Yagci, V. S. Özgur Kirca, Vasileios Kitsikoudis, Catherine A. M. E. Wilson, M. Furkan Celik, Caner Sertkan","doi":"10.1029/2023wr034978","DOIUrl":"https://doi.org/10.1029/2023wr034978","url":null,"abstract":"Flume experiments were conducted to comprehend the impact of different patterns of an emergent vegetation patch on the flow field and the scour process in natural rivers. Velocity measurements, flow visualization, and scour tests were undertaken around different vegetation patch patterns, which were simulated inspired by the expansion process of a typical instream vegetation. The patch expansion process was idealized with an initially circular patch of rigid emergent stems becoming elongated due to positive and negative feedbacks. The expansion of the vegetation patch was considered to occur in three stages, in which the density of the patch from the previous stage was increased while the patch was also elongated by connecting at its downstream side with another sparser vegetation patch. These stages were replicated succesively by increasing the density and elongating the patch. In this way, two processes (i.e., elongation and decrease in permeability), which usually have hydrodynamically opposite effects on flow fields, were simulated at the same obstruction. Despite generally elongated obstacles being streamlined bodies, the morphometric analysis obtained by laser scanner revealed that streamlined elongation of permeable patches amplifies global scour and enhances localization of the local scour hole. This situation implies that as the patch expands, in the wake region, the steady-wake region becomes shorter, turbulence diminishes, lateral shear stress enhances, and deposition cannot occur far from the patch. Consequently, as the patch expands, the hydrodynamic consequences may restrict further patch expansion after a certain length/density.","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"1 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139061058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a two-dimensional solution for unsaturated transient seepage flow in a trapezoidal region using analytical solutions for flow in a series of rectangular regions. The coupled formulation considers the interaction among fluid flow due to differences in head and displacement of soil particles. The solution in each rectangular region is derived using Laplace Transform and Discrete Fourier Series for two top boundary conditions: specified pressure head and specified flow rate. The accuracy of the proposed solution is verified by comparing the results against those attained from the finite difference method. The proposed solution is applied to two example problems, demonstrating its efficacy and accuracy. The findings show a significant difference in the coupled and uncoupled results for fine-grained soils possessing a small Gardner's coefficient. Additionally, the uncoupled pressure heads advanced quicker to a steady state than the coupled ones for soils with a small Gardner's coefficient. The coupling effect becomes less prominent as Gardner's coefficient increases. This study is the first attempt in the literature to provide a solution for unsaturated flow in a trapezoidal or non-rectangular domain using analytical solution techniques, which can better represent complex real-world applications (e.g., slopes, embankments, dams).
{"title":"Two-Dimensional Analytical Solution for Transient Flow in Unsaturated Soils Considering Hydromechanical Coupling","authors":"Fred T. Tracy, Farshid Vahedifard","doi":"10.1029/2023wr035326","DOIUrl":"https://doi.org/10.1029/2023wr035326","url":null,"abstract":"This paper presents a two-dimensional solution for unsaturated transient seepage flow in a trapezoidal region using analytical solutions for flow in a series of rectangular regions. The coupled formulation considers the interaction among fluid flow due to differences in head and displacement of soil particles. The solution in each rectangular region is derived using Laplace Transform and Discrete Fourier Series for two top boundary conditions: specified pressure head and specified flow rate. The accuracy of the proposed solution is verified by comparing the results against those attained from the finite difference method. The proposed solution is applied to two example problems, demonstrating its efficacy and accuracy. The findings show a significant difference in the coupled and uncoupled results for fine-grained soils possessing a small Gardner's coefficient. Additionally, the uncoupled pressure heads advanced quicker to a steady state than the coupled ones for soils with a small Gardner's coefficient. The coupling effect becomes less prominent as Gardner's coefficient increases. This study is the first attempt in the literature to provide a solution for unsaturated flow in a trapezoidal or non-rectangular domain using analytical solution techniques, which can better represent complex real-world applications (e.g., slopes, embankments, dams).","PeriodicalId":23799,"journal":{"name":"Water Resources Research","volume":"38 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139041593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：