1

One-month Stress PeriodConsiderations

Presentation to ESHMC8 January 2008

B. Contor

Courtesy Rick Raymondi

Outline

• MODFLOW & PEST considerations

• Recharge tool considerations

• Data considerations

MODFLOW & PEST considerations

1. Meaning of “Stress Period”

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 1 2 3 4 5 6

Stress

ModelOutput

Observations

Interpolated Match

MODFLOW & PEST considerations

2. Meaning of “Time Step”

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 1 2 3 4 5 6

Stress

ModelOutput

Observations

Interpolated Match

MODFLOW & PEST considerations

3. Observations occur when they occur

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 1 2 3 4 5 6

Stress

ModelOutput

Observations

Interpolated Match

MODFLOW & PEST considerations

4.Model output is interpolated to times of observations

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 1 2 3 4 5 6

Stress

ModelOutput

Observations

Interpolated Match

MODFLOW & PEST considerations

5. Match is calculated at the time the observation occurred

Something to think about:

MODFLOW

AquiferParameters

PE

ST

ESPAM 1.XProcess

MODFLOW

AquiferParameters

FORTRANRech. Tool

RechargeParameters

ESPAM 2.0Process?

Something to think about:

MODFLOW

~ 200 AquiferParameters

ESPAM 1.XProcess

runtime w/

44 stressperiods:a few seconds

PE

ST

Total PEST

runtime about 12 hrs.

Something to think about:

runtime w/324 stressperiods: ???

Total PESTruntime ????

MODFLOW

??? AquiferParameters

FORTRANRech. Tool

??? RechargeParameters

ESPAM 2.0Process?

runtime w/324 stressperiods: ???

runtime w/44 stressperiods: a few minutes

Overview of Recharge Tool

Review of Recharge Tool

• GIS tool – ArcGIS 8.x or 9.x– GW Modeling Toolbar (ArcGIS extension)– ESPAM.exe

• FORTRAN tool – Readinp.exe

Review of Recharge Tool

• GIS tool – ArcGIS 8.x or 9.x– GW Modeling Toolbar – ESPAM.exe

• FORTRAN tool – Readinp.exe

Data handling

Calculations

Input Data

GIS Points

GIS Lines

GIS Polygons

GIS Rasters

Tables

GIS Tool

Model Grid

Output Tables in Specific

Format

Start Creating Output Tables

(Stolen from May Training slides)

Output files Created by GIS Tool• .mdl - simulation and

scenario information

• .cel - model grid information

• .pch - perched reaches

• .trb - tributary underflow

• .cnl - canal seepage data

• .sol - soils

• .pre - precipitation

• .div - diversions and returns

• .fpt - fixed point sources and withdrawals

• .off - offsite ground water pumping

• .ent - irrigation entities

• .iar - irrigated agriculture

• .eti - irrigated lands evapotranspiration

• .red - irrigation discount table

• .nir - recharge on non-irrigated lands

• .spt - scenario sources and withdrawals

(Stolen from May Training slides)

GIS tool explicitly represents every stress period:

• .pch - perched reaches

• .trb - tributary underflow

• .cnl - canal seepage data

• .pre - precipitation

• .div - diversions and returns

• .fpt - fixed point sources and withdrawals

• .off - offsite ground water pumping

• .iar - irrigated agriculture

• .eti - irrigated lands evapotranspiration

• .red - irrigation discount table

• .nir - recharge on non-irrigated lands

• .spt - scenario sources and withdrawals

GIS tool uses single representation for entire simulation:

• .mdl - simulation and scenario information

• .cel - model grid information

• .ent - irrigation entities

• .sol - soils data

• .pch - perched reaches • .pre - precipitation• .div - diversions and

returns*• .fpt - fixed point sources

and withdrawals

• .off - offsite ground water pumping

• .eti - irrigated lands evapotranspiration

• .spt - scenario sources and withdrawals

Native data frequencyis one month or better

* interpolation will be required for a few small entities

Data frequency longer than one month but this matches physical

reality

• .mdl - simulation and scenario information

• .cel - model grid information

• .sol - soils

• .iar - irrigated agriculture

• .red - irrigation discount table

• .cnl - canal seepage data*

• .ent - entity data

* maybe

Data frequency is longer than one month, adjustment may be needed

• .trb - tributary underflow • .nir - recharge and non-irrigated lands

END

Courtesy Rick Allen