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ARCGIS Desktop, EPANET and Watershed. Hung- Cuong Pham Department of Chemical Engineering hungcuongknu@yahoo.com. ARCGIS Desktop. History of ESRI Products. ARC/INFO developed – 1980s* Couples INFO database with graphical tools for display and analysis Data structures Coverages Point
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ARCGIS Desktop, EPANET and Watershed Hung-Cuong Pham Department of Chemical Engineering hungcuongknu@yahoo.com
History of ESRI Products • ARC/INFO developed – 1980s* • Couples INFO database with graphical tools for display and analysis • Data structures • Coverages • Point • Arc/Line • Polygon
Brief History of ESRI Products • ArcView 1.0 – early 1990s • Very limited functionality • Display only • Buggy – crashes often • ARC/INFO continues to be enhanced by adding new commands • ARCTOOLS graphical interface attempts to make things simpler
Brief History of ESRI Products • ARCView versions 2 and 3 – mid to late 1990s • Greatly expanded capabilities • Data editing and analysis • AVENUE programming language allows extensions to be added to ARCVIEW • Data Structures • Shape Files (editable) • Coverages (display only) • Images • Grids (with extensions)
Brief History of ESRI Products • ArcGIS Desktop – 1999- present • Subsumes both ARC/INFO and ArcView • Restricted to Windows NT-family operating system • Arcview is a limited version of ARCGIS Desktop • Data Structures • Shape Files • Geodatabases • Script/Programming Language: Visual Basic
ArcGIS Components • ArcCatalog • Manage data • ArcMap • Create maps • Analysis • ArcToolbox • Stand-alone Analysis and Conversion • ArcScene • 3-D display
ARGIS Components • ARCMAP
ArcMap • ArcMap is designed to help you create publication-quality maps • It extends the display capabilities of ArcView 3 but uses an entirely new interface • Everything is there, but you will need to work to locate it
Description • EPANET models: • Flow of water in pipes, • Pressure at junctions, • Height of water in tanks, • Concentration of a chemical, • Water age, and • Source tracing ( trace the source of a contaminant
Applications: • Plan and improve a system’s hydraulic performance • Pipe, pump and valve placement and sizing • Energy minimization • Fire flow analysis • Vulnerability studies for security planning • Operator training • Maintain and improve the quality of water delivered to consumers Design sampling programs • Study disinfectant loss and by-product formation • Evaluate alternative strategies for improving water quality such as: • Altering source utilization within multi-source systems, • Modifying pumping and tank filling/emptying schedules to reduce water age, • Utilizing booster disinfection stations at key locations to maintain target residuals, and • Planning a cost-effective program of targeted pipe cleaning and replacement.
Water Quality Modeling Principles • Conservation of mass within differential lengths of pipe • Complete and instantaneous mixing of the water enteringpipe junctions • Appropriate kinetic expressions for the growth or decay of thesubstance as it flows through pipes and storage facilities This change in concentration can be expressed by a differentialequation of the form: This change in concentration can be expressed by a differentialequation of the form:
Where: – Cji is the substance concentration mass/ft3) at position x and time t in the link between nodes i and j – vij is the flow velocity in the link (equal to the link’s flow divided by its cross-sectional area in ft/sec – kij is the rate at which the substance reacts within the link (mass/ft3/sec)
Storage tanks can be modeled as completely mixed,variable volume reactors where the change in volumeand concentration over time are: Where:- Vs is the volume (ft3) of the tank- Cs is the concentration in tank s
The following equation represents the concentration of material leaving the junction and entering a pipe:
EPANET INPUT • Junctions • Coordinates (can import from GIS) • Elevation • Demand (gallons per minute) • Initial quality
EPANET INPUT • Pipes • Length • Diameter • Roughness coefficient ( Hazen-Williams C factor)
EPANET INPUT • Tanks data • Coordinates ( can import from GIS) • Elevation • Levels • Initial • Minimum • Maximum • Diameter • Volume
EPANET INPUT • Pumps Data • Start node • End node • Pump curve • Initial status (open, close)
EPANET OUTPUT • Junctions (nodes) • Pressure • Quality (e.g., residual chlorine concentration) • Pipes (links) • Flow (gallons per minute) • Velocity (ft per second) • Head loss (ft) • Tanks: inflow, level, quality • Pump: flow rate
Overview • Hydrology • Effect of urbanization • Stability concepts • Modeling • Hydrologic • Hydraulic • Examples
Watershed An area contributing runoff and sediment.
Factors That Affect Discharge • Precipitation • Antecedent moisture • Snow melt • Frozen ground • Spatial extent of storm • Ease of runoff movement (time of concentration) • Watershed size (delineation) • Soils • Land use Human activity can alter these.
Ease of Water Movement • Time of concentration is the time for runoff to travel from the hydraulically most distant point of the watershed. • Channelization, addition of drains, storm sewers, pavement, graded lawns, and bare soils convey water more rapidly.
The altered flow regime affects: • habitat (water velocity, temperature, sediment, other pollutants)
The altered flow regime affects: • habitat (water velocity, temperature, sediment, other pollutants) • flooding (frequency and elevation)
This is an active down-cut. Stability cannot be determined from one photo however.
Stream Instability causes excessive erosion at many locations throughout a stream reach.