Package net.simplace.sim.components.experimental.runoff

Class RunoffCurveNumberAPSIM

java.lang.Object
net.simplace.sim.model.FWSimComponent
net.simplace.sim.components.experimental.runoff.RunoffCurveNumberAPSIM
All Implemented Interfaces:
net.simplace.sim.util.FWSimFieldContainer
public class RunoffCurveNumberAPSIM extends net.simplace.sim.model.FWSimComponent

This SimComponent calculates runoff according to the SCS Runoff Curve Number method (USDA, 1972). The algorithm follows the same formulations used in the APSIM (Agricultural Production Systems sIMulator) platform, which was adapted from the PERFECT model (Littleboy et al., 1992).

The algorithm simulates runoff taking into account the potential runoff amount (iPotentialRunoff) (typically the amount of daily rainfall and irrigation), the soil moisture content (iSWC), and the soil cover fraction (iCoverFrac). The input soil water for each soil layer (iSWC) can be calculated by a soil water balance SimComponent (e.g., SlimWater), whereas soil cover fraction (iCoverFrac) (0-1) can be obtained by the SimComponent RunoffSurfaceCover.

The effect of soil moisture and surface cover is incorporated directly in the curve number value prescribed for bare soil conditions (cCNbare). Firstly, the effect of soil cover is computed by:

\[ \begin{eqnarray} CN_{CoverRed} & = & min \biggl( \frac{iCoverFrac}{cCNcov} \cdot cCNred, cCNred \biggl) \\ CN2 & = & max(0, cCN_{bare} - CN_{CoverRed}) \end{eqnarray} \]

Where iCoverFrac is the soil cover fraction (0-1); cCNcov is the fraction of surface cover at which the maximum reduction in CN occurs; cCNred is the maximum reduction in CN due to surface cover; cCNbare is the CN for the bare soil conditions; CNCoverRed is an intermediate variable and CN2 is the corrected CN due to soil surface cover. The CN2 is further corrected according to the fraction of soil moisture content by the following equations:

\[ \begin{eqnarray} FC_{frac[i]} & = & \frac{(iSWC_{[i]} - cWP_{[i]})}{(cFC_{[i]} - cWP_{[i]})} & \text{Where } (0 \le FC_{[i]} \le 1) \\ SF & = & \frac{1}{(1 - e^{-4.16})} \\ pWeight_{[i]} & = & SF \cdot \Biggl\{ 1 - e^{ \biggl[ -4.16 \cdot min \bigl( 1, \frac{D_{[i]}}{ED} \bigl) \biggl] } \Biggl\} \\ CNSW_{fac} & = & \sum_{i=1}^N (FC_{frac[i]} \cdot pWeight_{[i]}) \end{eqnarray} \]

Where iSWC is the soil water content (m3/m3); cFC is the field capacity (m3/m3); cWP is the wilting point (m3/m3); D (cDepth) is the depth of soil layer i (m); ED (cHydrolEffectiveDepth) is the effective depth (mm) for which soil moisture exerts influence in runoff (default value as 450 mm); pWeight is a weighting factor as a function of soil depth; SF is the scaling factor used for pWeight; and CNSWfac is the integrated soil moisture factor for all soil layers (N). The procedure describing how CNSWfac is used to scale the CN2 between dry and wet conditions is described below:

\[ \begin{eqnarray} CN1 & = & \frac{CN2}{(2.3340 - 0.013340 \cdot CN2)} \\ CN3 & = & \frac{CN2}{(0.4036 - 0.005964 \cdot CN2)} \\ CN_{final} & = & CN1 + (CN3 - CN1) \cdot CNSW_{fac} \end{eqnarray} \]

Where CN1 and CN3 are the wet and dry CN values respectively, which are calculated as a function of CN2; CNfinal is the final CN value corrected by soil cover and moisture. The numerical coefficients of equations 7 and 8 can be modified by changing the default values of cCN1a, cCN1b, cCN3a, cCN3b. However, changing these parameters should be made with extreme caution as it would affect the stability of CNfinal calculations. The CNfinal is then used in the curve number procedure as:

\[ \begin{eqnarray} s & = & 254 \cdot \biggl( \frac{100}{CN_{final}} - 1 \biggl) \\ Q & = & \frac{(P - \alpha \cdot s)^2}{P + (1 - \alpha) \cdot s} \end{eqnarray} \]

Where Q is the runoff (mm); s is an intermediate retention parameter calculated with CNfinal; P (iPotentialRunoff) is the potential runoff amount (mm) which is typically the amount of daily rainfall and/or sprinkler irrigation; \( \alpha \) (cIABSratio) is the initial abstraction factor used to correct infiltration after the start of runoff.

References

Soil Conservation Service (1972) National Engineering Handbook Section 4: Hydrology, Soil Conservation Service, USDA, Washington.

APSIM v7.1 source code. Last time accessed: Dec-14-2022. URL: https://github.com/APSIMInitiative/APSIMClassic

APSIM – SoilWat webpage. Last time accessed: 17-Apr-2023. URL: https://www.apsim.info/documentation/model-documentation/soil-modules-documentation/soilwat/

Littleboy, M., D.M. Silburn, D.M. Freebairn, D.R. Woodruff, G.L. Hammer, and J.K. Leslie. 1992. Impact of soil erosion on production in cropping systems. I. Development and validation of a simulation model. Aust. J. Soil Res. 30, 757-774.

Holzworth, Dean P., Neil I. Huth, Peter G. deVoil, Eric J. Zurcher, Neville I. Herrmann, Greg McLean, Karine Chenu, et al. "APSIM - Evolution towards a New Generation of Agricultural Systems Simulation." Environmental Modelling & Software 62 (December 2014): 327–350. https://doi.org/10.1016/j.envsoft.2014.07.009

Author:
Murilo Vianna, Gunther Krauss, gk@uni-bonn.de

Component Variables

Content TypeNameDescriptionData TypeUnitMin ValueMax ValueDefault Value
constantcDepthDepth of the bottom of each soil layer after soil layer transformationDOUBLEARRAYm---
constantcFCVolumetric soil water content of each layer at field capacityDOUBLEARRAYm3/m3---
constantcWPVolumetric soil water content of each layer at permanent wilting pointDOUBLEARRAYm3/m3---
inputiCoverFracPontential amount of water that can runoff (Rainfall for rainfed system; Rainfall+Irrigation for sprinkler irrigation) DOUBLEmm0.01000.0-
inputiPotentialRunoffPontential amount of water that can runoff (Rainfall for rainfed system; Rainfall+Irrigation for sprinkler irrigation) DOUBLEmm0.01000.0-
inputiSWCVolumetric soil water contentDOUBLEARRAYm3/m30.0--
outCN1CN2 at dry conditionDOUBLE1--0.0
outCN2bare soil CN corrected by surface cover (CNcoverRed)DOUBLE1--0.0
outCN3CN2 at wet conditionDOUBLE1--0.0
outCNSWfacSoil water factor to correct CNDOUBLE1--0.0
outCNcoverRedCN2 reduction due to surface coverDOUBLE1--0.0
outCNfinalFinal CN (corrected by soil cover and soil moisture)DOUBLE1--0.0
outRunoffRunoffDOUBLEmm0.010000.0-

  • Nested Class Summary

    Nested classes/interfaces inherited from class net.simplace.sim.model.FWSimComponent

    net.simplace.sim.model.FWSimComponent.TEST_STATE

  • Field Summary

    Fields inherited from class net.simplace.sim.model.FWSimComponent

    iFieldMap, iFrequence, iInputMap, iJexlRule, iMasterComponentGroup, iName, iOrderNumber, isComponentGroup, iSimComponentElement, iSimModel, iVarMap

  • Constructor Summary

    Constructors
    Constructor
    Description
    RunoffCurveNumberAPSIM()
    Empty constructor used by class.forName()

  • Method Summary

    Modifier and Type
    Method
    Description
    protected net.simplace.sim.model.FWSimComponent
    clone(net.simplace.sim.util.FWSimVarMap aVarMap)
     
    HashMap<String,net.simplace.sim.util.FWSimVariable<?>>
    createVariables()
    Create the FWSimVariables as interface for this SimComponent
    HashMap<String,net.simplace.sim.util.FWSimVariable<?>>
    fillTestVariables(int aParamIndex, net.simplace.sim.model.FWSimComponent.TEST_STATE aDefineOrCheck)
    called for single component test to check the components algorithm.
    protected void
    init()
    Initialises the fields by getting input and output FWSimVariables from VarMap
    protected void
    process()
    Process the algorithm and write the results back to VarMap

    Methods inherited from class net.simplace.sim.model.FWSimComponent

    addVariable, bind, checkCondition, createSimComponent, createSimComponent, createSimComponent, createSimComponent, doProcess, getConstantVariables, getContentType, getCreateFormXML, getDescription, getEditFormXML, getFieldMap, getFrequence, getFrequenceRuleScript, getInputs, getInputVariables, getMasterComponentGroup, getName, getOrderNumber, getOutputVariables, getVariable, getVariableField, getVarMap, initialize, isConditionCheck, isVariableAvailable, performLinks, performLinks, readInputs, removeVariable, reset, runComponentTest, setVariablesDefault, toComponentLinkingXML, toDocXML, toGroupXML, toOutputDefinitionXML, toResourcesDataXML, toResourcesDefinitionXML, toString, toXML, writeVarInfos

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • RunoffCurveNumberAPSIM

      public RunoffCurveNumberAPSIM()
      Empty constructor used by class.forName()

  • Method Details

    • createVariables

      public HashMap<String,net.simplace.sim.util.FWSimVariable<?>> createVariables()
      Create the FWSimVariables as interface for this SimComponent
      Specified by:
      createVariables in interface net.simplace.sim.util.FWSimFieldContainer
      Specified by:
      createVariables in class net.simplace.sim.model.FWSimComponent
      See Also:
      • net.simplace.simulation.model.FWSimComponent#createVariables()

    • init

      protected void init()
      Initialises the fields by getting input and output FWSimVariables from VarMap
      Specified by:
      init in class net.simplace.sim.model.FWSimComponent
      See Also:
      • net.simplace.simulation.model.FWSimComponent#init()

    • process

      protected void process()
      Process the algorithm and write the results back to VarMap
      Specified by:
      process in class net.simplace.sim.model.FWSimComponent
      See Also:
      • net.simplace.simulation.model.FWSimComponent#process()

    • fillTestVariables

      public HashMap<String,net.simplace.sim.util.FWSimVariable<?>> fillTestVariables(int aParamIndex, net.simplace.sim.model.FWSimComponent.TEST_STATE aDefineOrCheck)
      called for single component test to check the components algorithm.
      Specified by:
      fillTestVariables in class net.simplace.sim.model.FWSimComponent
      See Also:
      • net.simplace.sim.util.FWSimFieldContainer#fillTestVariables(int aParamIndex, TEST_STATE aDefineOrCheck)

    • clone

      protected net.simplace.sim.model.FWSimComponent clone(net.simplace.sim.util.FWSimVarMap aVarMap)
      Specified by:
      clone in class net.simplace.sim.model.FWSimComponent
      See Also:
      • net.simplace.simulation.model.FWSimComponent#clone(net.simplace.simulation.util.FWSimVarMap)