Yakima WATERS Mini Lesson
Flooding in the Yakima, by the numbers
Targets and Assessment
WA Science GLEs Addressed:
 6-8 ES2C In the water cycle, water evaporates from
Earth’s surface, rises and cools, condenses to form
clouds and falls as rain or snow and collects in bodies
of water.
 6-8 ES2G Landforms are created by processes that
build up structures and processes that break down and
carry away material through erosion and weathering.
 6 Math 6.6: Students refine their reasoning and
problem-solving skills. . .to understand and
communicate mathematical ideas, to make
generalizations, to draw logical conclusions, and to
verify the reasonableness of solutions to problems.
Assessments:
 Compare student preconceptions about causes of
local floods, with responses in Student Sheet. Grade
the student sheets.
Lesson Parameters
Content Area: Earth Science, Math
Overview: Learn about flood prediction and impacts by
reading, interpreting and comparing hydrographs of the
Yakima River.
Grade Level: 6-8
Suggested Time: 1 Class Period
Special Materials:
 Hydrograph and flood history data from local
watershed (provided for Yakima River*)
Learning Outcomes:
Knowledge: Students should be able to define a hydrograph and identify climatic, human, and environmental factors
that lead to flooding. Student awareness of local flood history and the human as well as ecological impacts of flooding
will increase.
Skill: Utilize numerical and graphical data to assess floods. Compare and analyze multiple sets of data.
Science Concept Background:
Through prior experimentation with stream tables and weather (storms) related curriculum, they understand they
understand the climatic and physiographic drivers of flood inducing storms. They also have personal experiences with
flooding in the local community or elsewhere. Students have created graphs to display and analyze results and have
interpreted graphs, to a limited extent. This exercise stretches beyond simple graph interpretation by asking students to
compare multiple datasets on one graph (years) as well as compare graphical data to tabular data.
Materials: (1 per student)
Hydrographs*
Flood History Tables*
Student sheets
Have students share the hydrographs and flood history tables and/or reuse for later classes. Links to these resources are
provided. *Data can be compiled for other locations using similar resources.
Procedure:
1. Getting started: Reflecting on personal experiences and assessing preconceptions. (10 min)
Have students reflect and share on personal experiences with flooding (recent floods are good timing!) by
journaling, sharing, or other method. Invite students to explain what conditions or changes in the environment
led to the occurrence of a specific flood.
2. Presentation: Introduction to Yakima River Flood History (10 min)
Introduce them to the history of flooding in the Yakima River Basin (refer to reference), tell stories, and share
photos to give perspective of what a major flood might have looked been like.
 Flood Hydrograph Example (5 min)
Show the recent flood hydrograph (and predicted forecast) on a powerpoint or camera projector and a
diagram of a stream gage station. Explain how stream flow and stage height are measured and have
students identify these levels on the hydrograph.
3. Student worksheets: Hydrograph Interpretation
Orient the students to the provided hydrographs and flood history table and have them complete the
worksheet.
4. Assessment and Wrap-up.
Assess student learning by checking answers. Wrap up by briefly discussing flooding prediction, flood damage,
and hazard prevention.
Key questions: What climate and environmental conditions led to the occurrence of this flood?
What are some ways scientists could measure a river?
What does a hydrograph tell us about a river?
Extension(s):
Have students draft outlines for a flood hazard prevention/mitigation plan for their community!
Compare actual flood inundation with floodplain maps.
Look at photos or videos of local and global floods.
Watch a video of a river at flood stage (see Sandy River example in Resources).
Have students read (or write their own) newspaper articles on a recent or historical flood event.
Teaching Tips:
This activity works well very recently after a recent flood in the local community. Depending on the classes’ level and
best work style, you can work on the student sheets as a class, or have students complete individually or in groups.
References:
Yakima County (2007). Upper Yakima River Comprehensive Flood Hazard
Management Plan. http://www.yakimacounty.us/surfacewater/Yakima_RCFHMP/Start.htm
This document contains the flood history table provided to the students and many wonderfully written descriptions of
the factors that led to the individual flood events, the damage caused by the flood events, as well as the cumulative
impacts of decades of flood management and mis-management. It is an excellent read prior to doing this activity and
can be utilized during the presentation for some key facts and numbers.
USGS. USGS 12484500 Yakima River at Umtanum, WA. Time series: daily data. Downloaded from
http://waterdata.usgs.gov/nwis?program=dv&site_no=12484500&agency_cd=USGS.
This is the internet link to the Umptanum Gage station on the Yakima River. You can use the provided hydrographs
for the time period/station you select. If you want to compare multiple flood event hydrographs you will need to
download the data. Time series: daily data (and other real-time or historical periods) can be downloaded for any
USGS gage station! Download the data into notepad, import into excel (as delimited) and remove the years from the
dates. More help on this topic is available on the USGS website.
Erikson, A. (2011). Sandy River Flood 2011: Sandy River flooding at Lolo Pass. Video online at
http://youtu.be/CPjEW0zTEuc (also try http://vimeo.com/18921387 if YouTube link does not work).
New Mexico Museum of Natural History. Interpreting a Hydrograph. The Bosque Education Guide: School-based
Activities. Accessed online at www.emnrd.state.nm.us/PRD/documents/InterpretingaHydrograph.pdf.
Supporting Documents:
Hydrographs
Flood History Table
Student Sheet
Presentation Slides
Author: Jamie Sheahan, Yakima WATERS Project, CWU, Winter 2011
Yakima River at Umptanum: 2009, 2011 hydrographs
2010-2011
2008-2009
41.00
Major Flood Stage = 39.00 ft
39.00
Moderate Flood Stage = 38.50 ft
River Stage (Feet)
37.00
Minor Flood Stage = 35.50 ft
35.00
Action Stage = 33.50 ft
33.00
31.00
29.00
1-Oct
1-Nov
1-Dec
1-Jan
1-Feb
1-Mar
1-Apr
Date
1-May
1-Jun
1-Jul
1-Aug
1-Sep
Source: Yakima County (2007). Upper Yakima Comprehensive Flood Management Plan
Source: Yakima County (2007). Upper Yakima Comprehensive Flood Management Plan
STUDENT SHEET: The power of the Yakima River
Reading a Hydrograph: Use the provided hydrographs of the Yakima River at Umtanum.
1. A hydrograph shows change in the ______________ of a river over time, typically measured in cubic
feet per second (cfs). It can also display the change in stage height of river over time.
2. During which months is the river typically the lowest?
3.
What were the flow levels December 1 of each of the years shown?
4. What causes low versus high flows at this time of the year?
5. Which year had more days in which the water stage was over 33.5 feet. How many days was it
over this level? This equals the duration of “bankfull stage” represents the amount of time when
the river is doing its most “work”, like eroding the banks and moving dirt and rocks downstream.
Flood History of the Yakima Basin Use the provided flood history table of the Yakima
6. When was the largest flood event in recorded history?
7. What was the flow (cfs) and river stage (feet)?
8. Compare the flow amount of the February 1996 flood in Table 4-1 to the flow of the 1996 flood at
Umptanum on the provided hydrograph. Which one had a higher peak flow? Circle the gage
station that you believe is the furthest downstream.
Peak flow from table (Gage station at Parker) = _________
Peak flow from Hydrography (Gage station at Umtanum) = _________