GSSHA User's Manual

Table of Contents

Preface

1 Introduction

1.1 History

1.2 Purpose

2 Model Formulation

2.1     Processes Simulated

2.2     Time Steps and Process Updates

2.3     Inputs

3 Project File

3.1     Required Inputs

3.2     Mapping Table – Optional

3.3     Overland Flow – Required

3.4     Interception – Optional

3.5     Rainfall Input and Options – Required

3.6     Infiltration – Optional

3.7     Channel Routing – Optional

3.8     Continuous Simulations – Optional

3.9     Saturated Groundwater Flow – Optional

3.10     Soil Erosion – Optional

3.11     Constituent Transport – Optional

3.12     Subsurface Drainage Network – Optional

3.13     Output Files – Required

4 General

4.1     Units

4.2     Grid Size

4.3     Total Event Simulation Time

4.4     Coordinate System

4.5     Map Headers

4.6     Watershed Mask

4.7     Elevation Map

4.8     Optimizations

5 Surface Water Routing

5.1     Channel Routing

5.2     Overland Flow Routing

5.3     Channel Boundary Conditions

5.4     Overland Boundary Conditions

5.5     Embankments

5.6     Overland/Channel Interaction

5.7     Introducing Discharge/Constituent Hydrographs

5.8     Overland Routing with Snow

5.9     Overland Routing with BMPs

6 Precipitation

6.1     Spatially and Temporally Uniform Precipitation

6.2     Spatially and Temporally Varied Precipitation

6.3     Interpolation Between Gages

6.4     Interception

7 Infiltration

7.1     Richards’ Equation

7.2     Green and Ampt (GA)

7.3     Multi-layer Green and Ampt

7.4     Green and Ampt with Redistribution (GAR)

7.5     Parameter Estimates

8 Groundwater

8.1     General

8.2     Formulation

8.3     Solution

8.4     Assignment of Parameter Values

8.5     Boundary Conditions

8.6     Coupling of the Saturated Zone Model with the Richards’ Equation Model of the Unsaturated Zone

8.7     Coupling of the Saturated Zone Model to the GA Type Infiltration Models

9 Continuous

9.1     Computation of Evaporation and Evapo-transpiration

9.2     Computation of Soil Moisture

9.3     Hydrometeorological Data

9.4     Snowfall Accumulation and Melting

9.5     Sequence of Events During Long-Term Simulations

10 Soil Erosion

10.1     Overland Erosion Formulation

10.2     Channel Sediment Transport Formulation

10.3     Sediment in Lake

10.4     Applicability of the Sediment Routing Methods

10.5     Simulations with Soil Erosion

11 Constituent Transport and Fate

11.1     Simulating Reactive Constituents in GSSHA

11.2     Transport Formulations

11.3     Simple Constituents

11.4     Point and Non-point sources

11.5     Multi-phase transport

12 Mapping Table

12.1     File Description

12.2     Index Maps

12.3     Grid-based Mapping Tables

12.4     ID Line Format

12.5     Example Mapping Table File

12.6     Stream Mapping Tables

12.7     Sediment Erosion Mapping Tables

12.7     Constituent Mapping Tables

13 Additional Inputs

13.1     Spatially and Temporally Varied Precipitation

13.2     Soil Layer Input File

13.3     Static Pumping Wells

13.4     Hydrometeorological Input File

14 Output

14.1     Required Flags and Files

14.2     Run Summary File

14.3     Optional Flags

14.4     Time Series Data at Internal Locations

14.5     WMS Hydrograph File

14.6     Time Series Maps

15 Creating Project Files

15.1     Simple Project File

15.2     Involved Project File

15.3     Continuous Simulation Project File

16 Building a Model

16.1     Delineating the Watershed

16.2     Selecting a Grid Size

16.3     Overland Flow Routing

16.4     Infiltration

16.5     Channel Routing

16.6     Single Event Calibration

16.7     Long-term Simulations

16.8     Saturated Groundwater Modeling

16.9     Calibration and Verification

16.10    Sediment Transport

16.11    Contaminant Transport

17 GSSHA File Formats

17.1     Project File

17.2     Mapping Tables

17.3     Stream Network Files

17.4     GRASS grid files

17.5     Nutrient Files

17.6     Time and Elevation Series Files

18 Alternate Run Modes

18.1     MPI and OpenMP Parallelization

18.2     Simulation Setup for Alternate Run Modes

18.3     Batch Mode Runs

18.4     Automated Calibration with Shuffled Complex Evolution

18.5     Monte Carlo Runs

18.6     ERDC Automated Model Calibration Software

   18.6.1     Efficient Local Search

   18.6.2     Multistart

   18.6.3     Trajectory Repulsion

   18.6.4     Effective and Efficient Stochastic Global Optimization

18.7     Inset Models

References