The Hydrologic Environment, from Drought to Flooding

Description:
This module helps students gain a basic understanding of the elements of the hydrologic cycle. Making use of illustrations, animations, and interactions, this module examines the basic concepts of the hydrologic cycle including water distribution, atmospheric water, surface water, groundwater, and snowpack/snowmelt.

Objectives:
Develop an understanding of the elements of the hydrologic cycle with the goal of making effective use of data sources and tools for forecasting

Introduction to Hydrologic Cycle:
Define the key features of hydrology and the hydrologic cycle
Name the components of the hydrologic cycle
Describe the basic concept of the Accounting Budget Approach for hydrology

Distribution:
Recognize the four main forms in which water is stored and distributed in the hydrologic cycle
Describe the key features of ocean water
Define the key features of surface water
Define groundwater and describe its key components

Atmospheric Water:
Identify the key processes in atmospheric water
Describe the significance of condensation and precipitation. Identify key methods and tools used in measurement.
Define evaporation and the key methods and tools for measurement. Describe the issues that complicate measurement process.
Define transpiration and describe its role in the rainfall-runoff process
Describe the varied rates of transpiration for different surface vegetation types

Surface Water:
Define the key processes associated with surface water: Infiltration, Soil Moisture, and Runoff
Identify the factors influencing infiltration
Describe the elements of soil composition
Describe possible soil conditions and how they affect infiltration
Define runoff and describe the use of the hydrograph in measuring it
Describe the elements of runoff

Groundwater:
Describe the importance of groundwater for the hydrologic cycle
Describe the characteristics of different types of aquifers
Define recharge
Describe natural and artificial recharge methods
Define withdrawal and describe its effects on a water table

Snowpack and Snowmelt:
Describe the critical role of snow and ice in the hydrologic cycle
Define snow water equivalent, and identify factors affecting snowmelt rate
Describe the key steps in the snowmelt process

Estimated time to complete: 1.5-2 h

Description:
This short course provides broadcast meteorologists with knowledge and instructional materials to help them understand watersheds as our environmental home and to help their viewers understand the relationship between the weather and the health and protection of the environment. Environmental impacts in many areas of the country result from the daily actions of people. We can easily see the consequences of a major oil spill at sea that is driven ashore by winds and ocean currents, but what about the fertilizer that people put on their lawns and the de-icer they apply to their driveway, or changing the car’s oil in the backyard, or the pet waste in the yard or local park? Combined with weather, all of these have an impact on both the local environment and the larger regional environment.


This short course takes a story-telling approach through the use of movie-like sequences of audio and imagery to show how the concept of a watershed can be related to local concerns and to connect it to people in a personal way. The goal of this course is to:

Provide an understanding of a watershed as the local environment in which people’s actions and decisions play against the background of daily and seasonal weather to affect the quality and health of their local watershed as well as the larger system of watersheds of which their watershed is one part.

Objectives:

• Know how to describe a watershed and locate the watersheds for your viewing region.


• Be able to find the hydrologic address of a watershed and describe how watersheds are interconnected into a river system.


• Be able to relate the concept of a watershed to urban settings.


• Know the distribution of water within a watershed and how to find water sources for a population center in your viewing area.


• Describe how sources of non-point pollution, especially in urban areas, impact water quality.


• Know how human-engineered changes in the watershed affect the location and severity of flooding following heavy precipitation events.


• Be able to relate the impact of drought on a watershed and watershed system.

Estimated time to complete: 2 h

Description:
This is part one of a two-module series on estimation of observed precipitation. Through use of rich illustrations, animations, and interactions, this module provides an overview of the science of precipitation estimation using various measuring platforms. First, we define quantitative precipitation estimation (QPE) and examine technologies for remote sensing of QPE, including radar and satellite and the strengths and limitations of each. That is followed by an examination of the use of rain gauges for precipitation estimation and important issues to consider with rain gauge measurement. Finally we provide an introduction to the strengths and limitations of using precipitation climatology for QPE including PRISM.

Objectives:
1. Define quantitative precipitation estimation (QPE).
2. List the tools used to measure precipitation.
3. Explain a drop size distribution (DSD).
4. Explain a Z-R relationship and its limitations in radar-derived QPE.
5. Explain how the radar’s ability to estimate snow QPE may differ from rain QPE.
6. Understand the basics of radar-derived precipitation from dual-polarized radar.
7. Illustrate what is meant by inconsistency in radar sampling and coverage.
8. Be able to use radar climatology guidance.
9. Describe the uses and limitations of satellite QPE.
10. List some of the limitations of rain gauge measurements.
11. Explain how wind, exposure, and turbulence can influence gauge catch for rain.
12. Explain how the gauge performance for snow may differ from rain.
13. Describe other ways to obtain snow water equivalent.
14. Describe the general strengths and limitations of measurement from automated gauges.
15. Explain how the strengths and limitations of manual gauge reports may differ from those of automated gauges.
16. Describe how precipitation climatology may enhance QPE.
17. Explain some key limitations of precipitation climatology.
18. Describe weather situations that would likely result in useful estimates from each of the three measurement tools: radar, satellite, and rain gauges.

Estimated time to complete: .75 - 1 h

Description:
The Runoff Processes module offers a thorough introduction to the runoff processes critical for flood and water supply prediction. Through the use of rich illustrations, animations, and interactions, this module explains key terminology and concepts including paths to runoff, basin and soil properties and runoff modeling. It also provides an introduction to the National Weather Service River Forecast System (NWSRFS). As a foundation topic for the Basic Hydrologic Science course, this module may be taken on its own or used as a supporting topic to provide factual scientific information to students as they complete the case-based forecasting modules.

Objectives:
Explain basic runoff processes:
* Define rainfall runoff
* Identify the general movement of water both on the surface and in the ground
* Recognize the different terms associated with groundwater and runoff
* Understand the relationship between precipitation/snowmelt rate and infiltration

Describe the paths for runoff:
* Identify the different types of runoff that occur both at and below the surface
* Recognize the influence of surface and soil properties that influence surface runoff
* Understand the soil properties that influence subsurface runoff, or interflow
* Anticipate the types of runoff you may expect in your area given the rainfall/snowmelt rate and the soil properties

Explain basic basin issues related to runoff:
* Recognize basin characteristics and how the relate to runoff processes
* Explain the impact of urbanization on runoff characteristics

Describe how soil properties affect runoff:
* Anticipate water movement and runoff given soil characteristics
* Identify important soil properties in your area
* Understand how both natural and human factors influence the behavior of water in the soil

Describe basic concepts of runoff modeling:
* Understand the basic concepts in runoff modeling
* Recognize why complex versus simple models are used
* Describe how a lumped model works
* Describe how a semi-distributed model works
* Describe how a distributed model works and the potential advantages as well as limitations

Describe features of basic National Weather Service River Forecast System (NWRFS) models:
* The key components and subcomponents of the NWRFS
* Basic concepts behind and components of the SACSMA model
* Basic concepts behind and components of the API and Continuous API models

Estimated time to complete: 2-2.5 h

Description:
The Flood Frequency Analysis module offers an introduction to the use of flood frequency analysis for flood prediction and planning. Through use of rich illustrations, animations, and interactions, this module explains the basic concepts, underlying issues, and methods for analyzing flood data. Common concepts such as the 100-year flood and return periods as well as issues affecting the statistical representation of floods are discussed. Common flood data analysis methods as well as an overview of design events are also covered. As a foundation topic for the Basic Hydrologic Science course, this module may be taken on its own, but it will also be available as a supporting topic providing factual scientific information to support students in completion of the case-based forecasting modules.

Objectives:

1. Explain key concepts in flood frequency analysis
• Define the meaning of return periods (i.e., the 100-year flood)
• Explain the exceedance probability and its relationship to return period
• Understand the two primary applications of flood frequency analyses


2. Understand key issues impacting the statistical representation of floods
• Explain how the period of record impacts flood frequency guidance
• Calculate the probability of occurrence or non-occurrence for a given flood magnitude over a specified duration
• Understand how basin changes may impact the behavior and frequency of floods, thus reducing the length of the period of record


3. Apply common methods for analyzing flood data
• Explain the basic concepts underlying both annual and partial duration time series
• Conduct a frequency analysis given peak flow data for a river


4. Explain purpose and application of design events
• Identify the reason for using design events
• Understand the usefulness of design events and their limitations and constraints
• Explain the concept of probable maximum event
• Understand the concept of standard project floods

Estimated time to complete: 1-2 h

Description:
According to NOAA’s National Weather Service, a flash flood is a life-threatening flood that begins within 6 hours--and often within 3 hours--of a causative event. That causative event can be intense rainfall, the failure of a dam, levee, or other structure that is impounding water, or the sudden rise of water level associated with river ice jams.
The “Flash Flood Processes” module offers an introduction to the distinguishing features of flash floods, the underlying hydrologic influences and the use of flash flood guidance (FFG) products. Through use of rich illustrations, animations, and interactions, this module explains the differences between flash floods and general floods and examines the hydrologic processes that impact flash flooding risk. In addition, it provides an introduction to the use of flash flood guidance (FFG) products including derivation from ThreshR and rainfall-runoff curves as well as current strengths and limitations.

Objectives:
Define a flash flood:
• Distinguish a flash flood from a general flood
• Identify the different physical processes leading to flash floods
• Recognize the connection between precipitation intensity and runoff characteristics associated with flash floods

Explain hydrologic influences on flash floods:
• Apply information about the runoff processes to the flash flood problem
• Explain why certain soil textures and soil profiles may result in greater flash flood risks
• Which physical characteristics make a basin more prone to flash flooding
• How quickly and frequently flash floods can occur in urban environments
• How fires and deforestation impact the flash flood risk

Understand key issues underlying the use of flash flood guidance (FFG) products:
• The definition of flash flood guidance
• How threshold runoff (ThreshR) and rainfall-runoff curves are used to derive flash flood guidance
• How flash flood guidance is generated for different spatial entities (headwater, county, gridded) and time durations
• Recognize when and how limitations can impact forecasts

Estimated time to complete: 1 h

Description:
This presentation by Dr. Eve Gruntfest raises important issues of how floods and other disasters, including land-falling hurricanes and their related warnings, affect public attitudes and actions. Awareness of these social science considerations is important for persons responsible for public weather warnings as well as other types of public interaction.

Estimated time to complete: 30 min

Description:
Understanding Drought--This webcast provides an introduction to drought. It presents the measures and scales of drought and how drought is monitored. It also covers how drought is predicted, the impacts of drought, and provides information about drought-related resources. This content serves as a foundation to learning more about climate variability and operational climate services and prepares users for the national implementation of NIDIS.
This module was last updated on Sept 28, 2009.

Objectives:
Upon completion of this training, the user will be able to:
List the main definitions of drought
Describe the measures and scales of drought severity
Describe the monitoring and indicator tools used to forecast changing drought conditions
Describe the impacts drought can have on an area including the intensity scale
List some local, regional, and national drought resources

Estimated time to complete: .75 - 1.00 h