Return to Delineating the Magat River Basin Model

Last Modified: 2023-06-20 15:30:08.859

Software Version

 HEC-HMS version 4.11 was used to create this tutorial. You will need to use HEC-HMS version 4.11, or newer, to open the project files.

Project Files

If you are continuing from Delineating the Magat River Basin Model you can continue to use your current project files. Otherwise download the initial project files here:

MagatRv_Delineated.zipobserved.dss

Rename Basin Elements

The delineated basin elements have automatically generated names. Use the Rename Basin Elements utility to provide project-specific names.

  1. In the Watershed Explorer, right click on the MagatRv basin model and select the Rename Basin Elements menu item.
  2. Rename the basin elements corresponding to the table below.
    Current NameNew Name
    Subbasin-3S_Upper
    Junction-2Bagabag
    Reach-2R_Upper
    Subbasin-2S_Lower
    Junction-1Inflow
    Reach-1R_Local
    Subbasin-1S_Local
    Sink-1Reservoir
  3. Click Apply. The basin elements are now renamed using project-specific identifiers.

Parameterize the Basin Elements

Select the MagatRv basin model node in the Watershed Explorer:

Discretization

  1. With the MagatRv basin model node selected, from the Parameters menu, select Discretization | Change Method.
  2. Select Structured.
  3. Click Change to set all subbasins to use the Structured discretization method.
  4. With the MagatRv basin model node selected, from the Parameters menu, select Discretization | Structured.

  5. Set Structured discretization parameters according to the table below:

    SubbasinProjectionCell Size (meters)
    S_UpperUTM 51 N2000
    S_LowerUTM 51 N2000
    S_LocalUTM 51 N2000
  6. Click Apply, then Close to commit the edits.
  7. From the GIS menu, select Compute | Grid Cells to compute grid cell geometries.

Once grid cells are computed, you can visualize this discretization by enabling the Discretization map layer:

Canopy

  1. With the MagatRv basin model node selected, from the Parameters menu, select Canopy | Change Method.
  2. Select Simple Canopy.
  3. Click Change to set all subbasins to use the Simple canopy method.
  4. With the MagatRv basin model node selected, from the Parameters menu, select Canopy | Simple Canopy.

  5. Set Simple canopy parameters according to the table below:

    SubbasinInitial Storage (%)Max Storage (MM)Crop CoefficientEvapotranspirationUptake Method
    S_Upper051.0Wet and Dry PeriodsSimple
    S_Lower051.0Wet and Dry PeriodsSimple
    S_Local051.0Wet and Dry PeriodsSimple
  6. Click Apply, then Close to save the edits.

Loss

  1. With the MagatRv basin model node selected, from the Parameters menu, select Loss | Change Method.
  2. Select Deficit and Constant.
  3. Click Change to set all subbasins to use the Deficit & Constant loss method.
  4. With the MagatRv basin model node selected, from the Parameters menu, select Loss | Deficit and Constant.

  5. Set Deficit and Constant loss parameters according to the table below:

    SubbasinInitial Deficit (MM)Maximum Storage (MM)Constant Rate (MM/HR)Impervious (%)

    S_Upper

    		510020.0
    S_Lower510020.0
    S_Local510020.0
  6. Click Apply, then Close to save the edits.

For more detail regarding the various Loss methods within HEC-HMS, including discussions on parameterization, see Applying Loss Methods within HEC-HMS.

Transform

  1. With the MagatRv basin model node selected, from the Parameters menu, select Transform | Change Method.
  2. Select ModClark.
  3. Click Change to set all subbasins to use the ModClark transform method.
  4. With the MagatRv basin model node selected, from the Parameters menu, select Transform | ModClark.

  5. Set ModClark transform parameters according to the table below:

    SubbasinTime of Concentration (HR)Storage Coefficient (HR)

    S_Upper

    		55
    S_Lower55
    S_Local22
  6. Click Apply, then Close to save the edits.

For more detail regarding the Clark unit hydrograph Transform method, including discussions on parameterization, see Estimating Clark Unit Hydrograph Parameters and Estimating Parameters with GIS Datasets.

Baseflow

  1. With the MagatRv basin model node selected, from the Parameters menu, select Baseflow | Change Method.
  2. Select Linear Reservoir.
  3. Click Change to set all subbasins to use the Linear Reservoir baseflow method.
  4. With the MagatRv basin model node selected, from the Parameters menu, select Baseflow | Linear Reservoir.

  5. Set Linear Reservoir baseflow parameters according to the table below:

    SubbasinNumber of LayerInitial TypeGW 1 Initial (M3/S/KM2)GW 1 FractionGW 1 Coefficient (HR)GW 1 Reservoirs

    S_Upper

    		1Discharge Per Area0.01

    1

    20

    1

    S_Lower1Discharge Per Area0.011

    20

    1

    S_Local1Discharge Per Area0.011201
  6. Click Apply, then Close to save the edits.

For more detail regarding the various Baseflow methods within HEC-HMS, including discussions on parameterization, see Applying Baseflow Methods in HEC-HMS.

Reach Routing

  1. With the MagatRv basin model node selected, from the Parameters menu, select Routing | Change Method.
  2. Select Lag.
  3. Click Change to set all reaches to use the Lag routing method.
  4. With the MagatRv basin model node selected, from the Parameters menu, select Routing | Lag.

  5. Set Lag routing parameters according to the table below:

    SubbasinInitial TypeLag Time (MIN)

    R_Upper

    		Discharge = Inflow

    180

    R_Local

    		Discharge = Inflow

    60

  6. Click Apply, then Close to save the edits.

For more detail regarding the various Reach Routing methods within HEC-HMS, including discussions on parameterization, see Applying Reach Routing Methods within HEC-HMS.

Add Observed Flow at the Bagabag Junction

For more in depth coverage of adding observed flow, see Viewing Observed Flow

Create Time-Series Data

  1. In HEC-HMS, select Components | Create Component | Time Series Data.
  2. Name the Time-Series Data Bagabag Gage.
  3. In the Watershed Explorer, select the Bagabag Gage Discharge Gage node.
  4. In the Component Editor, specify DSS Filename as <path to>/observed.dss, and specify DSS Pathname as //MAGAT/FLOW/31Dec2008 - 01Jan2011/1Day//.
  5. Click the program Save button.

It is best practice to store project files internal to the project directory. In this example we have moved observed.dss to <MagatRv project directory>/data/observed.dss.

Add Time-Series Data to Basin Element

Streamflow data was gathered from Philippines' Department of Public Works and Highways Streamflow Management System.


  1. In the Basin Map, right-click on the Bagabag junction and mark it as a computation point.
  2. In the Component Editor, for the Bagabag junction, set the Observed Flow gage to Bagabag Gage.

Summary

The basin model has been parameterized using initial parameter estimates. Further calibration of model parameters is necessary for a production forecasting model. The basin model is now ready for simulation with meteorologic boundary conditions.

Project Files

Download final project files here:

MagatRv_Parameterized.zip

Continue to Creating Boundary Conditions for the Magat River Basin Model