CEEN 5550 - Water Resources - 2nd Exam

Types of Systems

Natural, Social, and Abstract

How is what’s included in a system determined

Depends on how we define the system.

What is Systems Thinking

Solving complex, dynamic, ill-defined problems

Designing systems as well as components

Communicating with the wider community

Working with people from various disciplines and cultures

Meeting social, ethical, and environmental responsibilities while addressing challenges from engineering and science.

Managing projects and operating within business and political environments.

Three Tools for System Thinking

Rich Picture Diagrams

Casual Loop Diagrams

Behavior-over-time Graphs

Rich Picture Diagram

Uses diagrams to explore a situation or system, creating a mental model.

Pictures, Connections, Facts, Subjective Info, Conflict, Structure, and Process

Casual Loop Diagram

Explains the relationships between different variables in a system and how one variable can influence another which can drive feedback loops. 

Behavior-over-time Graphs

A line graph showing how a variable changes across a period of time. Can sketch trends in data. 

Why use modeling?

1. Predict System Behavior

2. Test Scenarios Safely

3. Support planning and decision making

Types of Water Resource Models

1. Hydrologic

2. Hydraulic

3. Urban Stormwater

4. Watershed & Water Quality

5. Planning & Allocation

Hydrologic Modeling Application

Rainfall - runoff

Hydraulic Modeling Application

River flow, floodplain

Urban Stormwater Modeling Application

Sewer systems

Watershed & Water Quality Modeling Application

Land use impacts

Planning & Allocation Modeling Application

Supply-demand

Modeling Process (6 Steps)

1. Define Problem

2. Set system boundaries

3. Collect Data

4. Build & Calibrate the model

5. Run Scenarios

6. Interpret results

HEC-HMS Applications

1. Watershed-scale hydrologic modeling for both rural and urban areas.

2. Flood forecasting and analysis, including design storms and historical events.

3. Storm water management and infrastructure design.

4. Climate change and land use impact studies on hydrology

HEC-HMS Outputs

1. Hydrographs

2. Peak discharge and volume

3. Rainfall-runoff relationships

4. Water balance components: Precipitation, Infiltration, Evapotranspiration

5. Scenario comparisons

HEC-HMS Data Required

1. Watershed Geometry

2. Meteorological Data

3. Land Surface Characteristics

4. Hydrologic Parameters

5. Calibration / Validation Data

HEC-HMS Loss Method: SCS Curve Number

Empirical method used to estimate direct runoff from rainfall events.

HEC-HMS Transform Method: SCS Unit Hydrograph

Empirical method used to transform excess precipitation into direct runoff hydrographs.

HEC-HMS Basin Model Creation Steps

1. Create a new project

2. Create a new basin model

3. Add hydrologic elements to the basin model

4. Select modeling methods

5. Parametrize modeling methods

HEC-HMS Components

Basin Model Structure

Meteorological Model Inputs

Control Specifications

Simulation Execution

Hydraulic Model

A mathematical representation of a water/sewer/storm system and is used to analyze the system’s hydraulic behavior.

Hydraulic Model Types

1D - Flow is one dimensional in both channel and floodplain

2D - Flow is two dimensional in both channel and floodplain

1D/2D - Combined 1D/2D, 1D in channel and 2D in floodplain

3D - Flow is considered 3D in both channel and floodplain

HEC-RAS Purpose

HEC-RAS models hydraulics of water flow through rivers and channels.

HEC-RAS Applications

Floodplain Management

River Engineering and Design

Dam Break Analysis

Environmental Modeling

HEC-RAS Components

Geometry Data

Flow Data

Boundary Conditions

Plan Files

Manning’s Roughness Coefficient (N)

A coefficient representing surface roughness and resistance to flow.

Steady Flow

Flow parameters do not change with time.

Unsteady Flow

Flow parameters change with time.

HEC-RAS Boundary Conditions

Inputs that define how water enters and exits the modeled system. 

HEC-RAS Data Requirements

Topographic Data

Hydrologic Data

Land Use and Infrastructure

HEC-RAS Modeling Steps

1. Import terrain and geometry

2. Define river reaches and cross-sections

3. Add hydraulic structures (if needed)

4. Input flow data and boundary conditions

5. Run simulations and analyze results

Stormwater Modeling Purpose

Simulates stormwater movement and quality in urban areas to manage flooding and pollution. 

SWMM Purpose

Models stormwater runoff quality and quantity for urban areas using dynamic simulations.

SWMM Applications

1. Design and sizing of drainage system components including detention facilities

2. Flood plain mapping of natural channel systems

3. Control of combined and sanitary sewer overflows

4. Generating non-point source pollution loading for wasteload allocation studies

5. Evaluating BMPs and LIDs for sustainability goals

SWMM Limitations

1. Not applicable to large-scale, non-urban watersheds

2. Not applicable to forested areas or irrigated cropland

3. Cannot be used with highly aggregated rainfall data

4. It’s an analysis tool, not an automated design tool

SWMM Components

1. Rainfall and Evaporation Inputs

2. Subcatchments

3. Drainage Network

4. Flow Routing and Water Quality

SWMM Required Data

1. Rainfall and Land Use Data

2. Soil Characteristics

3. Drainage Network Layout

4. Water Quality Parameters

SWMM Modeling Steps

1. Project Area and Base Maps

2. Subcatchments and Drainage Network

3. Climatic Data and Simulation Parameters

4. Simulation and Validation

Watershed & Water Quality Modeling Purpose

Simulates precipitation, infiltration, runoff, and streamflow in watersheds

SWAT Purpose

Predicts environmental impacts of land management on water and sediment in watersheds.

SWAT Applications

1. Water Quality

2. Agricultural Impacts

3. Watershed Management

4. Climate Studies

SWAT Limitations

Need extensive data and calibration; less precise for small-scale hydrological processes.

SWAT Components

1. Weather Generator

2. Hydrology

3. Soil erosion

4. Sediment Transport

5. Nutrient cycling modules

SWAT Required Data

1. DEM,

2. Land Use

3. Soil Properties

4. Detailed Climate Data

SWAT Modeling Steps

1. Defining Watershed Boundaries

2. Inputting Spatial and Temporal Data

3. Calibrating and Validating Model

4. Applying SWAT for Predictions