wasp7 course boundary conditions & pollutant loads

WASP7 Course

Boundary ConditionsBoundary Conditions&&

Pollutant LoadsPollutant Loads

Watershed & Water Quality Modeling Technical Support CenterWatershed & Water Quality Modeling Technical Support Center

WASP7 Course

What is a Boundary?What is a Boundary?

• Any Exchange of Water from outside the Any Exchange of Water from outside the model network in or from inside the model network in or from inside the network to the outside.network to the outside.

1 2 3 4 5 6

Boundary Boundary

We designate Boundaries as Segment 0

Limitation in WASPLimitation in WASPOnly 1 Boundary Per SegmentOnly 1 Boundary Per Segment

Limitation in WASPLimitation in WASPOnly 1 Boundary Per SegmentOnly 1 Boundary Per Segment


WASP7 Course

What is a Boundary?What is a Boundary?

• Defines Mass entering networkDefines Mass entering network

• WASP Calculates Mass LeavingWASP Calculates Mass Leaving• What if Flow Reverses?What if Flow Reverses?• Implication of BoundariesImplication of Boundaries

– Boundary concentrations (BCs) must be specified with reasonable accuracy

• Unknown BC is OK only if insensitive (i.e., changes in BC do not significantly change model prediction in Area of Interest)

• If the BC is sensitive and unknown, then extend the boundary location away from Area of Interest

Mass Loading = Flow ∙ Concentration


WASP7 Course

Specifying BoundariesSpecifying Boundaries

• Boundaries are defined byBoundaries are defined by– User Specified Flow Paths– User Specified Dispersion Paths– Read from Hydrodynamic Interface File


WASP7 Course

Steps to specify boundary Steps to specify boundary concentrations (BCs):concentrations (BCs):• Click on “+” by each variable to

unpack boundary segments • Highlight segment• In bottom window, fill in

concentration values (mg/L) for beginning and ending times

• As needed, add time rows by pressing “+ Insert” and edit Date, Time, and Value

• Continue entering BC data for all variables and boundary segments

• Press “iOK” and save

BoundariesBoundaries


WASP7 Course

LoadsLoads

• Mass per Time into Model NetworkMass per Time into Model Network– kg/day

• Loading PathwaysLoading Pathways– Atmospheric Deposition– Groundwater Infiltration– Municipal, Industrial Discharge– Watershed Runoff and Erosion


WASP7 Course

Loading PathwaysLoading Pathways

• Direct Discharges (i.e., point sources)Direct Discharges (i.e., point sources)

• External Loadings (i.e., non-point sources)External Loadings (i.e., non-point sources)– ASCII File– Created LWWM– Created HSPF– Combined Sewer Overflow– Groundwater Infiltration


WASP7 Course

Direct Loading Time FunctionsDirect Loading Time FunctionsFlows, dispersion coefficients, boundary Flows, dispersion coefficients, boundary

concentrations, and point source loads follow concentrations, and point source loads follow user-specified time functions, with linear user-specified time functions, with linear interpolation between points; loading values interpolation between points; loading values may be specified at arbitrary intervals may be specified at arbitrary intervals (fractions of a day to thousands of days):(fractions of a day to thousands of days):


WASP7 Course

External Loading Time FunctionsExternal Loading Time Functions

Nonpoint source loads follow step time Nonpoint source loads follow step time functions in a formatted external file; functions in a formatted external file; loading values may be specified at loading values may be specified at arbitrary intervals (fractions of a day to arbitrary intervals (fractions of a day to thousands of days):thousands of days):


WASP7 Course

Direct LoadsDirect Loads

Steps to specify loads:Steps to specify loads:• Highlight and right click on

variable• Select Add/Remove Loads• In new dialogue box, point

and click on boxes to select segments receiving loads (not shown in diagram)

• Press “iOK” at bottom of dialogue box

• Continue adding loading segments to varables


WASP7 Course

Direct Loads, continuedDirect Loads, continuedSteps to specify loads:Steps to specify loads:

• Click on + by variable to unpack loading segments

• Highlight segment• In bottom window, fill in

loading values (kg/day) for beginning and ending times

• As needed, add time rows by pressing “+ Insert” and edit Date, Time, and Value

• Continue entering loading data for all variables and segments

• Press “iOK” and save

Note: variables with concentrations in mg/L have loading values in kg/day


WASP7 Course

External LoadsExternal Loads

Steps to specify external Steps to specify external NPS loads:NPS loads:

• Click on “Use NPS file” box• Click on“ Browse”• In “Open” dialogue box,

browse and highlight appropriate nps file, then press “open”

• NPS File Name will appear in Parameters Screen

• Press “iOK” at bottom of Parameters Screen and save


WASP7 Course

Example NPS File (for TOXI)Example NPS File (for TOXI)

Number of loading segments

Number of loading systems

1st loading time (day)

Loads (kg/day) by segment (column) and by system (row)

Segment number(s)System number(s)

System names

2nd loading time (day)


3rd loading time (day)

Loads (kg/day) by segment (column) and by system (row) 4th loading time (day)



WASP7 Course

Results from NPS LoadingsResults from NPS Loadingsvolume of 1000 m3, no flows, no decay

1st Load 2nd Load

wasp7 course boundary conditions & pollutant loads

Documents

boundaries slide

segment slide

boundary segments

exchange of water

mass loading

boundary location

erosion slide

flow concentration slide