Sensitivity Analysis is an important assessment process performed to understand the sensitivity of parameters on the model outcomes hence help select the most representative parameter values and identify dominant model parameters for the model calibration. In this study, two watershed models developed using the Hydrologic Simulation Program (HSPF) for North and South Chickamauga Creek watersheds were evaluated for parameter sensitivity. Critical HSPF model parameters investigated for sensitivity included Lower Zone Nominal Soil Moisture Storage (LZSN), Index to Infiltration Capacity (INFILT), Interflow Inflow (INTFW), Lower Zone Evapotranspiration (LZETP), Upper Zone Nominal Soil Moisture Storage (UZSN) and Fraction of Groundwater Inflow to Deep Recharge (DEEPFR). Our paper will present the analysis results that will discuss relative sensitivity (normalized root mean square error in the model outputs due to the change in inputs), sensitivity factor (ratio of the percentage change in model output to percentage change in model parameter), and will explain the variability of model outcomes from the selected perturbations of input parameters. Overall, we noticed peak flow rate was mostly sensitive to INFILT, whereas annual runoff volume to LZETP and the other important parameters were found sensitive for calibrating the watershed hydrology.

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Sensitivity Analysis is an important assessment process performed to understand the sensitivity of parameters on the model outcomes hence help select the most representative parameter values and identify dominant model parameters for the model calibration. In this study, two watershed models developed using the Hydrologic Simulation Program (HSPF) for North and South Chickamauga Creek watersheds were evaluated for parameter sensitivity. Critical HSPF model parameters investigated for sensitivity included Lower Zone Nominal Soil Moisture Storage (LZSN), Index to Infiltration Capacity (INFILT), Interflow Inflow (INTFW), Lower Zone Evapotranspiration (LZETP), Upper Zone Nominal Soil Moisture Storage (UZSN) and Fraction of Groundwater Inflow to Deep Recharge (DEEPFR). Our paper will present the analysis results that will discuss relative sensitivity (normalized root mean square error in the model outputs due to the change in inputs), sensitivity factor (ratio of the percentage change in model output to percentage change in model parameter), and will explain the variability of model outcomes from the selected perturbations of input parameters. Overall, we noticed peak flow rate was mostly sensitive to INFILT, whereas annual runoff volume to LZETP and the other important parameters were found sensitive for calibrating the watershed hydrology.

**[Access the Conference Proceedings Paper on ASCE Library](https://doi.org/10.1061/9780784483466.051)** 

Parameter Sensitivity Analysis in Hydrological Modeling of a Watershed Dominated by Pervious Landcover

Created in 1999, the Environmental & Water Resources Institute (EWRI) is the recognized leader within ASCE for the integration of technical expertise and public policy in the planning, design, construction, and operation of environmentally sound and sustainable infrastructure impacting air, land and water resources.

[Paper Proceedings](https://doi.org/10.1061/9780784483466)

Conference DOI: https://doi.org/10.26226/m.6329c39b68fb0e00131f77d2