My first paper published in water professionals day symposium held in Post Graduate Institute of Agriculture (PGIA), University of Peradeniya, Sri Lanka on 1st Oct. 2005
The Lakeview Estates Lake Association (LELA) manages two reservoirs near Lexington, Kentucky that are used recreationally but impacted by surrounding urban development. LELA requested help monitoring water quality and mitigating impacts. A team tested water quality parameters biweekly at nine outfalls over four months. They developed a website to communicate advisories and tested a settling vault to reduce pollutants. The website was functional but resident feedback was not collected. Further testing of solutions on-site and gathering resident input could help tailor efforts to best benefit the community.
This document provides an overview of stream restoration, including definitions of key concepts like what constitutes a healthy stream and ecosystem restoration. It discusses common stream insults or degradation factors and describes several approaches to restoration, emphasizing the importance of designing projects based on a specified guiding image and reference reaches. Specific restoration components are outlined, such as reconnecting the channel to its floodplain, installing in-stream structures, and enhancing riparian buffers. Design methods like threshold channels, alluvial channels using regime equations, hydraulic geometry, and analytical models are also summarized.
This document discusses the feasibility of sluicing operations to manage sedimentation in run-of-river hydropower schemes in the Himalayan region. It notes that sedimentation is a major problem, reducing reservoir capacity over time. Sluicing involves flushing sediments from near the power intake to maintain water levels for power generation. The document provides an overview of factors affecting sluicing efficiency and results from physical model tests. It analyzes the dimensions of the scour cone formed during sluicing and lists relevant dimensionless parameters. Managing sedimentation through techniques like sluicing is important for the sustainable operation of run-of-river hydropower in sediment-laden Himalayan rivers.
Estimation of Groundwater Recharge Using WetSpass and MODFLOWPutika Ashfar Khoiri
The document discusses methods for estimating groundwater recharge using the WetSpass and MODFLOW models. WetSpass is a physically based model that uses inputs like land use, soil type, and climate data to calculate spatial patterns of evapotranspiration, surface runoff, and groundwater recharge. The recharge output from WetSpass is then used as input for the MODFLOW groundwater flow model. Together, WetSpass and MODFLOW allow for the simulation of spatially variable recharge and groundwater flow.
Modelling of a Coastal Aquifer using FEFLOWC. P. Kumar
This document summarizes a study on modelling coastal aquifer seawater intrusion using FEFLOW software. The study area is along the coast of North Goa, India where increasing groundwater extraction is causing intrusion. The objectives are to simulate intrusion under pumping scenarios, identify sensitive parameters, and suggest remedial measures. Field investigations were conducted to collect data on groundwater levels, quality and resistivity. A 3D finite element model was set up and calibrated. Results show intrusion currently extends 290m inland but could advance farther with lower rainfall or increased pumping. Sensitive parameters include hydraulic conductivity, dispersivity and rainfall. Continuous monitoring and groundwater management are recommended.
1) Streams undergo different stages of development as they erode their valleys and move towards base level. Early stages involve downcutting and creating V-shaped valleys while middle stages form floodplains and meanders through lateral erosion. Late stages rework floodplain sediments.
2) Stream characteristics like discharge, gradient, and channel shape determine a stream's velocity and ability to erode, transport, and deposit sediment. Meandering streams typically form point bars and floodplains while braided streams occur in areas with high sediment loads.
3) Drainage basins and divides define the areas where water flows into different streams and rivers. Stream piracy can occur when the headward erosion of one stream cuts
1) A study from the 1990s examined using a tidal gate at Throgs Neck to improve water quality in Long Island Sound by reducing pollutant concentrations and increasing dissolved oxygen levels.
2) Modeling showed the tidal gate could induce increased ocean water flow through Long Island Sound to the harbor, but may also alter tidal elevations and increase salinity.
3) While water treatment upgrades have led to improvements, a storm surge barrier could provide additional water quality benefits worth further investigation due to synergies between water quality and coastal protection goals.
1. The document analyzes the lateral migration of the Red River near Grand Forks, North Dakota over the past 142 years using historical aerial photographs, elevation models, and maps.
2. Measurement results show the channel has migrated noticeably in some areas, with a maximum distance of 1,455 meters. Migration rates average between 0.01-0.38 meters/year, showing a maximum of 54.4 meters of movement over 142 years.
3. The low rates of channel migration found indicate no potential risk to city infrastructure over the next 100 years from the slow moving, mud-dominated river.
The Lakeview Estates Lake Association (LELA) manages two reservoirs near Lexington, Kentucky that are used recreationally but impacted by surrounding urban development. LELA requested help monitoring water quality and mitigating impacts. A team tested water quality parameters biweekly at nine outfalls over four months. They developed a website to communicate advisories and tested a settling vault to reduce pollutants. The website was functional but resident feedback was not collected. Further testing of solutions on-site and gathering resident input could help tailor efforts to best benefit the community.
This document provides an overview of stream restoration, including definitions of key concepts like what constitutes a healthy stream and ecosystem restoration. It discusses common stream insults or degradation factors and describes several approaches to restoration, emphasizing the importance of designing projects based on a specified guiding image and reference reaches. Specific restoration components are outlined, such as reconnecting the channel to its floodplain, installing in-stream structures, and enhancing riparian buffers. Design methods like threshold channels, alluvial channels using regime equations, hydraulic geometry, and analytical models are also summarized.
This document discusses the feasibility of sluicing operations to manage sedimentation in run-of-river hydropower schemes in the Himalayan region. It notes that sedimentation is a major problem, reducing reservoir capacity over time. Sluicing involves flushing sediments from near the power intake to maintain water levels for power generation. The document provides an overview of factors affecting sluicing efficiency and results from physical model tests. It analyzes the dimensions of the scour cone formed during sluicing and lists relevant dimensionless parameters. Managing sedimentation through techniques like sluicing is important for the sustainable operation of run-of-river hydropower in sediment-laden Himalayan rivers.
Estimation of Groundwater Recharge Using WetSpass and MODFLOWPutika Ashfar Khoiri
The document discusses methods for estimating groundwater recharge using the WetSpass and MODFLOW models. WetSpass is a physically based model that uses inputs like land use, soil type, and climate data to calculate spatial patterns of evapotranspiration, surface runoff, and groundwater recharge. The recharge output from WetSpass is then used as input for the MODFLOW groundwater flow model. Together, WetSpass and MODFLOW allow for the simulation of spatially variable recharge and groundwater flow.
Modelling of a Coastal Aquifer using FEFLOWC. P. Kumar
This document summarizes a study on modelling coastal aquifer seawater intrusion using FEFLOW software. The study area is along the coast of North Goa, India where increasing groundwater extraction is causing intrusion. The objectives are to simulate intrusion under pumping scenarios, identify sensitive parameters, and suggest remedial measures. Field investigations were conducted to collect data on groundwater levels, quality and resistivity. A 3D finite element model was set up and calibrated. Results show intrusion currently extends 290m inland but could advance farther with lower rainfall or increased pumping. Sensitive parameters include hydraulic conductivity, dispersivity and rainfall. Continuous monitoring and groundwater management are recommended.
1) Streams undergo different stages of development as they erode their valleys and move towards base level. Early stages involve downcutting and creating V-shaped valleys while middle stages form floodplains and meanders through lateral erosion. Late stages rework floodplain sediments.
2) Stream characteristics like discharge, gradient, and channel shape determine a stream's velocity and ability to erode, transport, and deposit sediment. Meandering streams typically form point bars and floodplains while braided streams occur in areas with high sediment loads.
3) Drainage basins and divides define the areas where water flows into different streams and rivers. Stream piracy can occur when the headward erosion of one stream cuts
1) A study from the 1990s examined using a tidal gate at Throgs Neck to improve water quality in Long Island Sound by reducing pollutant concentrations and increasing dissolved oxygen levels.
2) Modeling showed the tidal gate could induce increased ocean water flow through Long Island Sound to the harbor, but may also alter tidal elevations and increase salinity.
3) While water treatment upgrades have led to improvements, a storm surge barrier could provide additional water quality benefits worth further investigation due to synergies between water quality and coastal protection goals.
1. The document analyzes the lateral migration of the Red River near Grand Forks, North Dakota over the past 142 years using historical aerial photographs, elevation models, and maps.
2. Measurement results show the channel has migrated noticeably in some areas, with a maximum distance of 1,455 meters. Migration rates average between 0.01-0.38 meters/year, showing a maximum of 54.4 meters of movement over 142 years.
3. The low rates of channel migration found indicate no potential risk to city infrastructure over the next 100 years from the slow moving, mud-dominated river.
Hydrodynamics and Morphological Changes Numerical Model of the Jeneberang Est...AM Publications
Jeneberang Estuary, located south of Makassar, Indonesia, is one of the largest and most important river in Sulawesi. In this paper, a numerical model has recently been developed hydrodynamic and morphological evolution of the downstream rubber dam of the Jeneberang Estuary. The hydrodynamic model is derived from the hydro static assumption and Boussinesq approximation. A high-resolution computational grid was generated covering the Jeneberang estuary. The model was run with time driven by tidal forcing at the ocean boundary and river hydro graph at the upstream. The observed tidal data and hydrography were accessible for the set-up of the model. Hydrodynamic simulations have been performed and computed water levels were compared to observations of existing water level along the estuary from DISHIDRO data. For the period of a neap-spring-neap cycle, the model settings determined in the calibration process are verified satisfactions with respect to water level measurements. Good agreement was shown between model results and observed temporal and spatial variations in water elevation and currents, in the Jeneberang Estuary. The suspended sediments were generally transported from the Jeneberang River towards the Makassar Strait when overflow discharge through the Jeneberang Rubber Dam. Morphology change at the Jeneberang Estuary delta is affected by many factors, including tide, waves, river flows and sediment
The Vietnam National Mekong Committee conducted a Mekong Dam Study, the results of which were presented at the Greater Mekong Forum on Water, Food and Energy in Phnom Penh on Oct. 21, 2015. This is part one of their overview presentation.
The Vietnam National Mekong Committee conducted a Mekong Dam Study, the results of which were presented at the Greater Mekong Forum on Water, Food and Energy in Phnom Penh on Oct. 21, 2015. This presentation overviews their Modelling for the study.
The Vietnam National Mekong Committee conducted a Mekong Dam Study, the results of which were presented at the Greater Mekong Forum on Water, Food and Energy in Phnom Penh on Oct. 21, 2015. This presentation overviews their Fisheries Impact Assessment.
This document discusses methods for estimating groundwater potential and balance. It provides an overview of key concepts like the hydrologic cycle, national water policy regarding groundwater, and the groundwater balance equation. The document also outlines data requirements, methodology, and methods for estimating individual components of the groundwater balance like recharge from rainfall, recharge from canals, and evapotranspiration from groundwater. Empirical formulas and norms from expert committees are presented for calculating various recharge coefficients.
A REVIEW ON RESERVOIR SEDIMENTATION STUDIES USING SATELLITE REMOTE SENSING TE...ijiert bestjournal
Sedimentation in the reservoir gradually reduces it s storage capacity. By keeping a check on the sedimentation and by providing control measures for the same,the reservoir life can be maintained. Uj jani dam was constructed for irrigation,water supply an d power generation schemes. It lies in Solapur dist rict which is a drought prone area. This makes Ujjani a socially and economically significant project for t he state. In the present study,reservoir sedimentatio n for Ujjani reservoir is assessed for monitoring p urpose. Two techniques namely Satellite Remote Sensing Tech nique (SRST) and mathematical modeling using HEC RAS,were used in the study for estimating sedi mentation. Owing to advantages like low cost,time saving,less manpower requirement,accuracy in esti mation and capability of carrying out past surveys,the Satellite Remote Sensing Technique is gaining impor tance over the time consuming and high cost conventional hydrographic surveys. The water spread areas for different reservoir levels were delineat ed from the satellite images of Ujjain Reservoir using ARC GIS software. Volume between two water levels was calculated using prismoidul formula. The presen t volume of reservoir was compared with the initial volume during impoundment of reservoir. This gave t he loss of volume which was due to sedimentation.
Hymo alterations – survey methods
Workshop on Ecological classification of surface water bodies in EUWI+ pilot areas of Belarus, Ukraine and Moldova,
June 19 - 20, 2018
Kyiv, Ukraine
This document discusses groundwater flow patterns and regional groundwater systems. It covers topics such as recharge and discharge zones, effects of basin geometry, local vs regional flow systems, mapping flow systems using data on topography, piezometers, hydrochemistry, and isotopes. It also discusses interactions between groundwater and lakes/wetlands, noncyclical groundwater, saltwater encroachment issues and solutions, and quantitative analysis of recharge and discharge rates using flow net construction.
1) Tropical Storm Irene caused record flooding in many Massachusetts rivers, with some peak flows having less than a 0.2% probability of occurring in a given year.
2) The flooding showed that rivers will access their floodplains and erode and deposit sediment in ways that change their channels over time if not prevented by infrastructure like undersized culverts.
3) Massachusetts has established stream crossing standards to maintain river processes and continuity, and these standards are now required under various state permits and regulations. Adhering to these standards helps infrastructure withstand floods like Irene while allowing rivers more natural function.
Diversion channels are artificial channels that provide an alternative route for excess water during floods, helping to mitigate flood effects and restore rivers to their natural water levels. They are typically built around communities and economic centers to prevent extensive flood damage. Diversion channels come in different types, including portable check dams, diversion boxes, turnout boxes, and pipe turnouts. Their main purposes are to divert water away from the main river channel and provide flood control, municipal water supply, and irrigation.
Methods Of Flood Control For Assessmentguest3d8cbf
The document discusses methods of flood control and river management. It describes various causes of flooding such as heavy rain, urbanization, dam collapse, tsunamis, snowmelt, monsoons, and global warming. Common flood control techniques include building dams and pumping stations, barriers like embankments and flood walls, altering river channels by straightening and widening them, and controlling land use near rivers. The Mississippi and Nile Rivers are discussed as examples, with details provided about the extensive levee system along the Mississippi and the Aswan High Dam on the Nile.
This document summarizes a study assessing bank stability in Garvin Brook in Minnesota using Rosgen's BEHI/NBS method. The stream was divided into 5 sections and field measurements were used to calculate BEHI ratings, which ranged from moderate to low downstream. NBS ratings throughout were low to moderate. Channel migration rates derived from aerial photos did not correlate well with BEHI/NBS ratings. While Rosgen's method provided some insight, more data like a bank pin study may be needed to fully evaluate bank stability in this stream.
The document summarizes a hydrologic report on flooding and sedimentation in the Magasawang Tubig and Bucayao River Basins in Oriental Mindoro, Philippines. It describes the area, stream types and geometry, flow regimes, sedimentation and flooding problems, and identifies mitigation measures. Key findings include extensive sediment deposition from upstream rivers loosening after a 1994 earthquake, flood flows bifurcating from one river to another, and recommendations for comprehensive basin studies and erosion control.
The ICAR Indian Institute of Water Management was established in 1988 and aims to develop improved water management technologies through research. It conducts research through five programs: rainwater management, canal water management, groundwater management, waterlogged area management, and on-farm research and technology transfer.
The document then discusses the design of creek irrigation systems. It defines tidal creeks and explains how salinity varies in creeks over tidal cycles. It also discusses factors that influence salinity changes like urbanization. The document outlines the process for designing creek irrigation systems which includes determining design discharge, selecting a cross-sectional shape based on soil type and erosion control needs, using Manning's formula to calculate dimensions, and adding freeboard
Pohick Creek Watershed: Dam Rehabilitation Dredging and Lake RestorationFairfax County
The document discusses plans to rehabilitate dams and dredge lakes in the Pohick Creek Watershed in Fairfax County, Virginia. It details work already completed at Royal Lake, Woodglen Lake, and Lake Barton dams and spillways. It also outlines upcoming projects to dredge Huntsman Lake and Royal Lake to restore sediment storage capacity and water quality. Rehabilitation of Huntsman Lake dam is scheduled for fall 2013.
The document discusses flood damage to structures and flood control/proofing alternatives. It notes that flood damage depends on water depth, time of inundation, contaminants, and flow speed. Static water causes interior damage while dynamic water adds exterior pressure. Relocating structures to higher ground removes obstructions from the floodplain and benefits river processes and fish habitat. Elevating structures onto new foundations has mixed effects, depending on foundation type and whether other flood protection measures can be removed.
The document summarizes a public presentation on Typhoon Ondoy (Ketsana) and the Marikina River flood of September 26, 2009. It includes information on rainfall intensity and flood frequency statistics for the Marikina River Basin. It also discusses hydrologic modeling of the basin that was conducted, which estimated a peak flood discharge of 5770 cubic meters per second for the 2009 event, exceeding the previous 100-year flood level.
The document proposes two scenarios for restoring fish migration past a bottom sill on the Somesul Mic River in Apahida, Romania. The first scenario involves constructing a bypass canal with an upstream wooden basin to supplement water flow. The second scenario involves constructing two concrete basins downstream of the sill, connected by an intermediate concrete canal, to facilitate fish passage over the sill in stages. Both scenarios aim to restore longitudinal connectivity for migratory fish species like nase and barbel while complying with EU water directives.
Chapter 1 introduction to hydraulics structures history...Mohsin Siddique
Hydraulic structures have been developed for thousands of years to control water flow for irrigation and water supply. Early examples include canals, dams, and irrigation networks developed by ancient Egyptians and Mesopotamians. Conventional hydraulic design is an iterative process relying on an engineer's experience. Optimization and economic analysis can lead to more optimal designs. Risk analysis is also important as hydraulic structures always face uncertainties and risks of failure from hydrologic, hydraulic, structural, and economic sources. Assessing load and resistance with reliability and safety factor analysis allows quantification of risks.
The document provides background information on Scott Creek and Waddell Creek lagoons in Santa Cruz County, California. It describes the historical and current conditions of the lagoons and how they have been impacted by development, including the construction of Highway 1 bridges. For Scott Creek, the bridge construction in 1939 realigned the creek, filling in the historical lagoon and reducing the tidal interface. This altered the lagoon's morphology and isolated wetland areas from tidal influence. The frequency and duration of the lagoon opening is important for salmonid migration and habitat but has been impacted by development. The document discusses various processes and concepts for understanding coastal lagoon dynamics and how bridges may influence factors like inlet stability, tidal pr
Increasing the use of library and self-motivated learning by Problem Based Le...santharooban
Increasing the use of library and self-motivated learning by Problem Based Learning (PBL) approach at Faculty of Health-Care Sciences, EUSL.
Paper presented at ARS 2010, EUSL
Hydrodynamics and Morphological Changes Numerical Model of the Jeneberang Est...AM Publications
Jeneberang Estuary, located south of Makassar, Indonesia, is one of the largest and most important river in Sulawesi. In this paper, a numerical model has recently been developed hydrodynamic and morphological evolution of the downstream rubber dam of the Jeneberang Estuary. The hydrodynamic model is derived from the hydro static assumption and Boussinesq approximation. A high-resolution computational grid was generated covering the Jeneberang estuary. The model was run with time driven by tidal forcing at the ocean boundary and river hydro graph at the upstream. The observed tidal data and hydrography were accessible for the set-up of the model. Hydrodynamic simulations have been performed and computed water levels were compared to observations of existing water level along the estuary from DISHIDRO data. For the period of a neap-spring-neap cycle, the model settings determined in the calibration process are verified satisfactions with respect to water level measurements. Good agreement was shown between model results and observed temporal and spatial variations in water elevation and currents, in the Jeneberang Estuary. The suspended sediments were generally transported from the Jeneberang River towards the Makassar Strait when overflow discharge through the Jeneberang Rubber Dam. Morphology change at the Jeneberang Estuary delta is affected by many factors, including tide, waves, river flows and sediment
The Vietnam National Mekong Committee conducted a Mekong Dam Study, the results of which were presented at the Greater Mekong Forum on Water, Food and Energy in Phnom Penh on Oct. 21, 2015. This is part one of their overview presentation.
The Vietnam National Mekong Committee conducted a Mekong Dam Study, the results of which were presented at the Greater Mekong Forum on Water, Food and Energy in Phnom Penh on Oct. 21, 2015. This presentation overviews their Modelling for the study.
The Vietnam National Mekong Committee conducted a Mekong Dam Study, the results of which were presented at the Greater Mekong Forum on Water, Food and Energy in Phnom Penh on Oct. 21, 2015. This presentation overviews their Fisheries Impact Assessment.
This document discusses methods for estimating groundwater potential and balance. It provides an overview of key concepts like the hydrologic cycle, national water policy regarding groundwater, and the groundwater balance equation. The document also outlines data requirements, methodology, and methods for estimating individual components of the groundwater balance like recharge from rainfall, recharge from canals, and evapotranspiration from groundwater. Empirical formulas and norms from expert committees are presented for calculating various recharge coefficients.
A REVIEW ON RESERVOIR SEDIMENTATION STUDIES USING SATELLITE REMOTE SENSING TE...ijiert bestjournal
Sedimentation in the reservoir gradually reduces it s storage capacity. By keeping a check on the sedimentation and by providing control measures for the same,the reservoir life can be maintained. Uj jani dam was constructed for irrigation,water supply an d power generation schemes. It lies in Solapur dist rict which is a drought prone area. This makes Ujjani a socially and economically significant project for t he state. In the present study,reservoir sedimentatio n for Ujjani reservoir is assessed for monitoring p urpose. Two techniques namely Satellite Remote Sensing Tech nique (SRST) and mathematical modeling using HEC RAS,were used in the study for estimating sedi mentation. Owing to advantages like low cost,time saving,less manpower requirement,accuracy in esti mation and capability of carrying out past surveys,the Satellite Remote Sensing Technique is gaining impor tance over the time consuming and high cost conventional hydrographic surveys. The water spread areas for different reservoir levels were delineat ed from the satellite images of Ujjain Reservoir using ARC GIS software. Volume between two water levels was calculated using prismoidul formula. The presen t volume of reservoir was compared with the initial volume during impoundment of reservoir. This gave t he loss of volume which was due to sedimentation.
Hymo alterations – survey methods
Workshop on Ecological classification of surface water bodies in EUWI+ pilot areas of Belarus, Ukraine and Moldova,
June 19 - 20, 2018
Kyiv, Ukraine
This document discusses groundwater flow patterns and regional groundwater systems. It covers topics such as recharge and discharge zones, effects of basin geometry, local vs regional flow systems, mapping flow systems using data on topography, piezometers, hydrochemistry, and isotopes. It also discusses interactions between groundwater and lakes/wetlands, noncyclical groundwater, saltwater encroachment issues and solutions, and quantitative analysis of recharge and discharge rates using flow net construction.
1) Tropical Storm Irene caused record flooding in many Massachusetts rivers, with some peak flows having less than a 0.2% probability of occurring in a given year.
2) The flooding showed that rivers will access their floodplains and erode and deposit sediment in ways that change their channels over time if not prevented by infrastructure like undersized culverts.
3) Massachusetts has established stream crossing standards to maintain river processes and continuity, and these standards are now required under various state permits and regulations. Adhering to these standards helps infrastructure withstand floods like Irene while allowing rivers more natural function.
Diversion channels are artificial channels that provide an alternative route for excess water during floods, helping to mitigate flood effects and restore rivers to their natural water levels. They are typically built around communities and economic centers to prevent extensive flood damage. Diversion channels come in different types, including portable check dams, diversion boxes, turnout boxes, and pipe turnouts. Their main purposes are to divert water away from the main river channel and provide flood control, municipal water supply, and irrigation.
Methods Of Flood Control For Assessmentguest3d8cbf
The document discusses methods of flood control and river management. It describes various causes of flooding such as heavy rain, urbanization, dam collapse, tsunamis, snowmelt, monsoons, and global warming. Common flood control techniques include building dams and pumping stations, barriers like embankments and flood walls, altering river channels by straightening and widening them, and controlling land use near rivers. The Mississippi and Nile Rivers are discussed as examples, with details provided about the extensive levee system along the Mississippi and the Aswan High Dam on the Nile.
This document summarizes a study assessing bank stability in Garvin Brook in Minnesota using Rosgen's BEHI/NBS method. The stream was divided into 5 sections and field measurements were used to calculate BEHI ratings, which ranged from moderate to low downstream. NBS ratings throughout were low to moderate. Channel migration rates derived from aerial photos did not correlate well with BEHI/NBS ratings. While Rosgen's method provided some insight, more data like a bank pin study may be needed to fully evaluate bank stability in this stream.
The document summarizes a hydrologic report on flooding and sedimentation in the Magasawang Tubig and Bucayao River Basins in Oriental Mindoro, Philippines. It describes the area, stream types and geometry, flow regimes, sedimentation and flooding problems, and identifies mitigation measures. Key findings include extensive sediment deposition from upstream rivers loosening after a 1994 earthquake, flood flows bifurcating from one river to another, and recommendations for comprehensive basin studies and erosion control.
The ICAR Indian Institute of Water Management was established in 1988 and aims to develop improved water management technologies through research. It conducts research through five programs: rainwater management, canal water management, groundwater management, waterlogged area management, and on-farm research and technology transfer.
The document then discusses the design of creek irrigation systems. It defines tidal creeks and explains how salinity varies in creeks over tidal cycles. It also discusses factors that influence salinity changes like urbanization. The document outlines the process for designing creek irrigation systems which includes determining design discharge, selecting a cross-sectional shape based on soil type and erosion control needs, using Manning's formula to calculate dimensions, and adding freeboard
Pohick Creek Watershed: Dam Rehabilitation Dredging and Lake RestorationFairfax County
The document discusses plans to rehabilitate dams and dredge lakes in the Pohick Creek Watershed in Fairfax County, Virginia. It details work already completed at Royal Lake, Woodglen Lake, and Lake Barton dams and spillways. It also outlines upcoming projects to dredge Huntsman Lake and Royal Lake to restore sediment storage capacity and water quality. Rehabilitation of Huntsman Lake dam is scheduled for fall 2013.
The document discusses flood damage to structures and flood control/proofing alternatives. It notes that flood damage depends on water depth, time of inundation, contaminants, and flow speed. Static water causes interior damage while dynamic water adds exterior pressure. Relocating structures to higher ground removes obstructions from the floodplain and benefits river processes and fish habitat. Elevating structures onto new foundations has mixed effects, depending on foundation type and whether other flood protection measures can be removed.
The document summarizes a public presentation on Typhoon Ondoy (Ketsana) and the Marikina River flood of September 26, 2009. It includes information on rainfall intensity and flood frequency statistics for the Marikina River Basin. It also discusses hydrologic modeling of the basin that was conducted, which estimated a peak flood discharge of 5770 cubic meters per second for the 2009 event, exceeding the previous 100-year flood level.
The document proposes two scenarios for restoring fish migration past a bottom sill on the Somesul Mic River in Apahida, Romania. The first scenario involves constructing a bypass canal with an upstream wooden basin to supplement water flow. The second scenario involves constructing two concrete basins downstream of the sill, connected by an intermediate concrete canal, to facilitate fish passage over the sill in stages. Both scenarios aim to restore longitudinal connectivity for migratory fish species like nase and barbel while complying with EU water directives.
Chapter 1 introduction to hydraulics structures history...Mohsin Siddique
Hydraulic structures have been developed for thousands of years to control water flow for irrigation and water supply. Early examples include canals, dams, and irrigation networks developed by ancient Egyptians and Mesopotamians. Conventional hydraulic design is an iterative process relying on an engineer's experience. Optimization and economic analysis can lead to more optimal designs. Risk analysis is also important as hydraulic structures always face uncertainties and risks of failure from hydrologic, hydraulic, structural, and economic sources. Assessing load and resistance with reliability and safety factor analysis allows quantification of risks.
The document provides background information on Scott Creek and Waddell Creek lagoons in Santa Cruz County, California. It describes the historical and current conditions of the lagoons and how they have been impacted by development, including the construction of Highway 1 bridges. For Scott Creek, the bridge construction in 1939 realigned the creek, filling in the historical lagoon and reducing the tidal interface. This altered the lagoon's morphology and isolated wetland areas from tidal influence. The frequency and duration of the lagoon opening is important for salmonid migration and habitat but has been impacted by development. The document discusses various processes and concepts for understanding coastal lagoon dynamics and how bridges may influence factors like inlet stability, tidal pr
Increasing the use of library and self-motivated learning by Problem Based Le...santharooban
Increasing the use of library and self-motivated learning by Problem Based Learning (PBL) approach at Faculty of Health-Care Sciences, EUSL.
Paper presented at ARS 2010, EUSL
This document summarizes Sri Lanka's National Strategy and Action Plan (NSAP) for the Mangroves for the Future (MFF) programme. The NSAP was developed in response to extensive damage to Sri Lanka's coastal ecosystems from the 2004 Indian Ocean tsunami. The plan establishes policies and a Strategic Action Plan to promote integrated coastal zone management and the sustainable development of coastal areas. The NSAP aims to address issues such as unsustainable development, conflicting uses of coastal resources, and gaps in coastal management capacity and knowledge. It outlines strategies for ecosystem restoration, stakeholder participation, and monitoring and adapting the plan over time based on learning. The overall goal is to develop healthier, more prosperous and secure coastal communities through long-
An Appraisal of Mangrove Management in Micro-tidal Estuaries and Lagoons in S...santharooban
The document provides background information on IUCN, the organization commissioning the study, and its mission to find pragmatic solutions to environmental challenges through scientific research and collaboration. It then introduces the study which was inspired by observations of inconsistent results from post-tsunami mangrove planting efforts in Sri Lanka. The study included two colloquia with stakeholders and field observations to discuss experiences with mangrove replanting and their effects on coastal ecosystems. The consensus was that mangrove planting should be scientifically-based and recognize the natural resilience of ecosystems to recover from disasters with minimal interventions.
Acid sulfate soils form in coastal areas when pyrite in low-lying wetland soils is exposed to oxygen through drainage or excavation. This produces sulfuric acid and releases toxic quantities of aluminum and iron. In Sri Lanka, acid sulfate soils are found along the southwest coast and impact the environment through killing aquatic life, degrading habitats, and stunting plant growth. They also pose health risks to humans and damage infrastructure through corrosion. Current management strategies aim to neutralize acidity through lime or isolate acid sulfate soils with barriers.
1) DNA fingerprinting is a technique used to identify individuals by their unique DNA patterns. It analyzes Variable Number Tandem Repeats (VNTRs) in DNA, which vary between people.
2) The Southern blot technique is used to detect and analyze VNTRs. It involves extracting DNA from a sample, cutting it, separating fragments by size, and probing for specific VNTRs.
3) PCR (polymerase chain reaction) is used to amplify small DNA samples. It heats and cools DNA in cycles to make billions of copies of specific DNA regions for analysis.
1) The document discusses the opportunity for technology to improve organizational efficiency and transition economies into a "smart and clean world."
2) It argues that aggregate efficiency has stalled at around 22% for 30 years due to limitations of the Second Industrial Revolution, but that digitizing transport, energy, and communication through technologies like blockchain can help manage resources and increase efficiency.
3) Technologies like precision agriculture, cloud computing, robotics, and autonomous vehicles may allow for "dematerialization" and do more with fewer physical resources through effects like reduced waste and need for transportation/logistics infrastructure.
This document discusses the hydrodynamic processes in the Meghna Estuary of Bangladesh. It analyzes tidal characteristics, flow patterns, and other factors like discharge, salinity, and sediment transport in the estuary. Some key findings are:
1) The estuary experiences a semi-diurnal tide with tidal ranges from 0-2m in the west to over 8m in the east near Sandwip Island, where tidal amplification occurs.
2) River discharge dominates in the dry season while tides are stronger. In the monsoon, discharge increases up to 160,000m3/s while tides remain influential.
3) Net flow analysis found about 50% of the Lower Me
Fish passage solution for Mănăştur dam!Răzvan Voicu
This document proposes a solution for fish migration on the Somesul Mic River upstream and downstream of the Manastur Dam in Cluj Napoca, Romania. Currently, the fish ladder at the dam is inoperable and blocks migration of important fish species. The proposed solution involves modifying the existing fish ladder by removing obstacles, cutting a rectangular opening, and adding two concrete modules above the dam that would guide water and fish in a gradual slope. This low-cost solution aims to restore longitudinal connectivity on the river and protect biodiversity while not impacting the dam structure. If implemented, it could help reestablish migratory fish populations and the ecological balance of the ecosystem.
Overbank Flow Condition in a River SectionIDES Editor
When the flows in natural or man made channel
sections exceed the main channel depth, the adjoining
floodplains become inundated and carry part of the river
discharge. Due to different hydraulic conditions prevailing in
the river and floodplain of a compound channel, the mean
velocity in the main channel and in the floodplain are different.
This leads to the transfer of momentum between the main
channel water and that of the floodplain making the flow
structure more complex. Results of some experiments
concerning the overbank flow distribution in a compound
channel are presented. Flow sharing in river channels is
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Evaluating the Impacts of an Improperly Designed Bridge across the Batticaloa Lagoon
1. Evaluating the Impacts of an Improperly Designed
Bridge across the Batticaloa Lagoon
S. Santharooban
Department of Zoology, Eastern University, Sri Lanka, Batticaloa, Sri Lanka
And
M. Manobavan
North East Costal Community Development Project, Batticaloa, Sri Lanka
Abstract
This research paper mainly focuses on the negative repercussions, resulting from
the construction of a New Bridge (Puthupalam), on the Batticaloa lagoon.
Construction of a New Bridge across Batticaloa lagoon is an adverse modification,
which will change the spatial structure of the Batticaloa lagoon while
simultaneously destruct the biodiversity of the lagoon. In this research, simulation
modeling approach is used to support the hypothesis, which assumes that this New
Bridge negatively impacts on the lagoon ecosystem by reducing the depth which
will change the spatial system of the Batticaloa lagoon. In this respect,
commercially available modeling software STELLA® (Version 7.0.3) was used to
conceptually develop a simulation model, called N-BIOL (New Bridge Impact on
Lagoon) based on the idea of literature and the measurements of lagoon depth and
water velocity, which showed the differences on either side of the New Bridge.
According to the simulated outputs, it is obvious that this New Bridge gradually
reduces the depth over time, which leads to the change of spatial structure of the
Batticaloa lagoon.
Keywords: Ecosystem, Simulation model, Spatial structure, Sediments
Introduction
Lagoons are an important part of the cultural landscape of the Batticaloa district.
The Batticaloa lagoon (7o 24’- 7o 46’ N and 81o 35’- 81o 49’ E) is the largest of
three lagoons (i.e. Batticaloa lagoon, Vakarai lagoon and Valaichchenai lagoon) in
the Batticaloa district and it occupies an area of 168 square kilometers and is 56 km
long (Shanmugaratnam, 1995). The maximum depth of the lagoon is about four
meters (Scot, 1989). More than 90% of the lagoon is located in Batticaloa district,
but the southern end near Kalmunai is located in the Ampara district. The deep
broad lagoon leads into the sea by three Bar mouths, namely Paalameenmadu Bar
mouth in Batticaloa, Periyakallar Bar mouth and Koddaikallar Bar mouth. The
flow of the water is towards the bar mouth when the Bar mouth is remains open
(mostly during the rainy season) and vice versa. This lagoon supports
economically and esthetically to those, who are living closer to it, as it comprises a
Water Professionals’ Day Symposium – October, 2005
2. Evaluating the Impacts of an Improperly Designed Bridge across the Batticaloa Lagoon
rich variety of aquatic flora (mainly mangroves) and fauna. In addition to this,
Batticaloa lagoon and its peripheral systems act as a form of natural rainwater
harvesting mechanism and can be considered as an important groundwater
recharging zone (Manobavan and Jeyakumar, 2004). The Batticaloa lagoon also
acts as a shock absorber of the Tsunami impact (within its limit) via its peripheral
wetlands and interconnected channels (Manobavan, 2005). The Batticaloa lagoon
comprises several islands within it, namely Puliyantheevu, Mantheevu,
Erumaitheevu (Buffalo Island), Sirayatheevu, Elubutheevu (Bone Island). In these
islands, the Puliyantheevu is important island as it holds central city of the
Batticaloa. Population is mainly concentrated in this island and this created a need
to have bridges across the Batticaloa lagoon to connect the island with the main
land of the Batticaloa district. As a result, three bridges, namely Koddamunai
Bridge, Puthur Bridge and New Bridge (Puthupalam1) were constructed across the
Batticaloa lagoon (Figure 01). The objective of this research paper is to evaluate
the negative environmental impacts, generated by the construction of a New Bridge
in the Batticaloa lagoon.
Figure 01: Location of Bridges across the Batticaloa lagoon (L and R represent the
Left and Right sides, respectively of the New Bridge, and the Bridge is 9.0 m
wide).
1
‘Tamil’ word for New Bridge and this was constructed in the year of 1985.
Water Resources Research in Sri Lanka
3. S. Santharooban And M. Manobavan
Outline of the Problem
Even though this New Bridge and contiguous road is extended for less than quarter
kilometer over the Batticaloa lagoon, it allows only a small opening for the
provision of the natural water flow. Hence, this bridge and associated road acts as
partial impoundments or as a quasi-dam across the lagoon. This partial
impoundment of this road is suspected to be creating lots of problems on lagoon
system dynamics and its spatial structure. And, it is also suspected to be changing
the biodiversity of the lagoon. This bridge may alter the flow regime by reducing
the water velocity of the lagoon due to its insufficient openings. According to the
results obtained from sampling2, the velocity variation curve was plotted (Figure
02c). According to Figure 02c, when water flows from left to right across the
bridge, the current velocity is decreased in right side or vice versa. This reduction
in velocity is resulted from partial impoundments and it is also obvious from the
graph (Figure 02c) that the velocity under the bridge is high. This can be explained
by using Equation 1.
AV = k [01]
Where; k – Flow rate
A – The cross sectional area of the stream
V- Fluid velocity
This equation can be applied to incompressible and non-viscous fluid undergoing
steady flow on a streamline (Roger, 1981). In applying this equation (Eq. 1) to this
lagoon system, when the water velocity is increased as the cross sectional area
decreases i.e. when width of the lagoon decreases, the water velocity is increased to
maintain an equal flow rate in all points. It is important to note here that when the
velocity under the bridge increases, the soil erosion is accelerated. This is
supported from the results of sampling as shown in Figure 02a, where the P is the
proximal point to the bridge (at the edge) and has high depth and S is the distal
point to bridge (120 m from either side) and has low depth and Q and R are points
in between (The distance between each two point is 40 km). This indicates the
erosion of lagoon bed under the bridge. This eroded bed load will accumulate in
one side leading to the further depth reduction.
Allan (1995) stated that extensive phytoplankton blooms often develop as a
consequence of slowed passage of water. In supporting this comment, it was
obvious that there was heavy accumulation of waste, aquatic macrophytes, algal
2
Sampling was done periodically across the New Bridge from 6th December 2004
to 11th April 2005 to measure the water current velocity and lagoon depth in either
side of the New Bridge (Figure 01)
Water Professionals’ Day Symposium – October, 2005
4. Evaluating the Impacts of an Improperly Designed Bridge across the Batticaloa Lagoon
bloom3 (Chladophora sp dominates the algal bloom in the left side of the bridge)
the in left side of the lagoon due to the New Bridge and contiguous road. When all
these accumulates decompose, the suspended solid particles increase, which in
turns increasing the turbidity of the water (Figure 02b). According to Figure 02b, it
is obvious that the turbidity is high in many points in the left side than in the right
side. The results further show that turbidity is significant difference between two
sides of the bridge (t= 2.871, p= 0.014 for two tail two sample student t-test).
Hence, these increased loads of suspended solid particles undergo sedimentation by
the influence of reduced current velocity. This increased sedimentation will result
the reduction of depth in this area. This can be supported by the results, which
showed a statistically significant difference in two sides (t= -8.077, p= 0.00 for the
two tail two sample student t-test) and this can be shown by the graph (Figure 02d),
which clearly indicates that the average depth of the center of lagoon is high in
right side (R) than in left.
As the depth is reduced then again velocity of the water is reduced according to the
following Manning equation for velocity of flow in a channel (in metric units)
1 2 / 3 1/ 2
U = R S [2]
n
Where; R is the hydraulic radius about equal to mean depth for most channels, S is
the energy gradient; approximately the slope of the water surface and n is the
Manning resistance coefficient (Barns, 1967).
Apart from this New Bridge (Puthupalam), there is another bridge, called Puthur
Bridge, which also lacks the proper natural water flow. As a result, a pond like
portion, enclosed by two bridges was created in left side (L) of the New Bridge
(Figure 01). Hence, as a combined effect of these two bridges, there will be a
heavy depth reduction in the area of the lagoon, enclosed by the New Bridge and
Puthur Bridge. This in future makes the change in the lagoon spatial system. In
this research, the modeling approach is used to predict the temporal changes of the
lagoon depth.
Hypothesis:
Batticaloa lagoon has been divided in to two half by the construction of the New
Bridge (Puthupalam), which negatively impacts on lagoon system by creating the
depth reduction in lagoon and this depth reduction will change the spatial process
of the Batticaloa lagoon overtime.
Water Resources Research in Sri Lanka
5. S. Santharooban And M. Manobavan
250 50 L R
Turbidity (FAU)
200 L R 40
Depth (cm)
150 30
100 20
50
10
0
0
P Q R S
1 2 3 4 5 6 7 8 9 10111213
Location from Bridge
Week s
P is proximal point to New Bridge and S is
the distal point to New Bridge
(a) (b)
(a)
L
Under Bridge
0.6 R 200 L R
0 180
0.4 160
0
140
Depth (cm)
0.2 120
0
100
Velocity (M/S)
0 80
1 2 3 4 5 6 7 8 9 10 11 12 13 0
60
-0.2
- 40
20
-0.4
- 0
1 2 3 4 5 6 7 8 9 10111213
-0.6 -
Weeks
We eks
-0.8 -
Water flow direction from L to R is assumed as
positive and from R to L is assumed as negative
(c) (d)
Figure 02: Graphical results of sampling carried out across the New Bridge in
lagoon; (a) Depth of lagoon in different localities from New Bridge; (b) Turbidity
variation on either side of New Bridge; (c) Variation in water velocity in either side
of Bridge; (d) Variation in lagoon depth in either side of the Bridge.
Water Professionals’ Day Symposium – October, 2005
6. Evaluating the Impacts of an Improperly Designed Bridge across the Batticaloa Lagoon
Development of a Conceptual Model
As already mentioned, a modeling approach is used to predict the changes in
future. A model is a formulation that mimics real world phenomena and by means
of which predictions can be made (Odum, 1971). We can continually study the
behavior of systems by creating mental or conceptual models of them. The
conceptual model uses the conceptual idea of the modeler. In this research, a
conceptual model was developed using commeciallly available modeling software
STELLA® Version 7.0.3. The STELLA software provides a simple, icon-based
language that enables ones to construct their understanding of any dynamic
phenomenon, occurring in the world. A conceptual model was developed as shown
in Figure 03, based on the idea of literature evidences and sampling data, presented
in section 2.0. Based on the conceptual model (Figure 03), another conceptual
model, called N-BIOL (New Bridge Impacts on Lagoon) was developed using
STELLA modeling platform. This is shown in Figure 04. This STELLA
conceptual model was simulated for ten years to obtain the simulation output.
Length of New Bridge Road
across the lagoon is increased
Velocity of water in
Water flowing width either side of road is Waste, phytoplankton and
of lagoon is reduced aquatic macrophytes are
decreased
accumulated
Sedimentation is
increased
Velocity under the
bridge increases
Changes in spatial
Depth of lagoon is structure of
decreased lagoon
Erosion of lagoon
bed is accelerated
Temperature of water
increases
Figure 03: Conceptual model developed based on literature evidence and results of
sampling by authors.
Water Resources Research in Sri Lanka
7. S. Santharooban And M. Manobavan
water in lagoon water out flow
water inflow
stagnation of accumulates
concentration of accumulates ~
~ Turbidity
inflow of accumulates accumulates
Water velocity
out flow of accumulates
Depth of water
inflow of solid particles sedimentation
amount of suspended
solid particles out flow of solid paticles
water temperature
Figure 04: The model developed using the STELLA modeling software.
Simulation Results and Discussion
The simulation output shown in following Figure 5a, indicates that the amount of
suspended solid particles increases while accumulate fluctuate with time. Because
of the reduced out flow of accumulates by the crossing structure, they retains in the
lagoon and at the same time they undergo decomposition, thereby accumulates
fluctuate with time. However, suspended solid particles are recruited with time as
accumulates undergo decomposition, so that, the amount of suspended solid
particles increases with time. However, it is expected that there will be seasonal
variations as accumulates have high rate of settlement in the non-rainy seasons, and
could undergo a state of disturbance in the wet season. Hence, the simulation
shows seasonal lows and highs, though the general trend as a whole is that of an
increasing one for the amount of suspended particles in the lagoon bed.
Water Professionals’ Day Symposium – October, 2005
8. Evaluating the Impacts of an Improperly Designed Bridge across the Batticaloa Lagoon
(a)
1: Depth of water 2: Amount of suspended solid particles 3: Sedimentation
(b)
Figure 05: Simulation outputs of Model N-BIOL (a) Temporal variation of
amount of accumulates and amount of suspended solid particles; (b) Temporal
Water Resources Research in Sri Lanka
9. S. Santharooban And M. Manobavan
variation of depth of lagoon, amount of suspended solid particles and
sedimentation.
The simulation output, shown in Figure 05b, indicates that the sedimentation
process increases overtime as the suspended solid particles increases.
Sedimentation can also be increased due to the reduction of current velocity.
However, it is not shown in the computer simulated model. And this output also
indicates the depth variation overtime, which is our key concern. According to this
output, depth of the lagoon will gradually decrease overtime. This reduction will
be possible in the portion of lagoon, where the accumulations are high. Hence, this
depth reduction now was observed in left side of the New Bridge after twenty years
of time period. Moreover, it should be noted that as shown in Figure 05b, the
seasonal fluctuation in accumulates influences the seasonal fluctuation of the depth
as well. Therefore, in the Batticaloa lagoon especially in left side of the New
Bridge (Figure 01), which is enclosed by the presence of two bridges, namely New
Bridge (Puthupalam) and Puthur Bridge, the lagoon depth will be reduced
gradually with time. As a result, the lagoon bed will be raised (since its depth is
reduced) and in the long run it will evolve into a semi-dry land, which will be dried
out in dry seasons and be flooded in wet seasons. This will lead to disturb the
biodiversity even further. This is supported by the modeling outputs (Figure 05),
and the lagoon depth will be reduced further in future affecting the aquatic
biodiversity.
It should be noted that since the simulations outputs are the result of a conceptual
modeling exercise, hence the validation of the model output results against the field
data gathered becomes impossible. Whilst this could be taken as a weaker element
in this exercise, considering the timeframe and the resources needed, such a
validation becomes an activity that is beyond the scope of this project.
Conclusions
The New Bridge functions as a partial impoundment across the Batticaloa Lagoon
and increases the sedimentation over space and time in the area of the lagoon,
enclosed by the New Bridge and Puthur Bridge. Increased levels of sedimentation
could be due to the following reasons:
• During the rainy season, lagoon receives floodwater which carries huge
amount of debris and sand.
• When the floodwater drain from the lagoon through the New Bridge, only
the surface water drains, while debris and sand accumulate on the bottom.
• Algal blooms, waste accumulation, and aquatic macrophyets also increase
the sedimentation when they undergo decomposition.
Water Professionals’ Day Symposium – October, 2005
10. Evaluating the Impacts of an Improperly Designed Bridge across the Batticaloa Lagoon
• The reduced velocity, resulted from partial stagnation of water also
increases the sedimentation.
• Therefore, depth of lagoon, especially the area, enclosed by the New
Bridge and Puthur Bridge will gradually decrease overtime.
• Furthermore, increased algal bloom will facilitate the plant succession,
which leads to the formation of dry vegetation in that particular locality.
Therefore, as hypothesized in section 2.0, this New Bridge and contiguous road
structure negatively impacts on the Batticaloa lagoon by creating the depth
reduction and hence, it will create the change in the spatial structure of the
Batticaloa lagoon and a reduction of the biodiversity consequently.
References
Allan, J.D. (1995). Stream ecology, structure and function of running waters.
Chapman and Hall publication, pp: 310-323.
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