Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Author: Anthony Williams, Williamsport High School, Washington County Public Schools
Background Information
Subject:
Identify the course the unit will be implemented in.
Grade Band:
Identify the appropriate grade band for the lesson.
Duration:
Identify the time frame for the unit.
Overview:
Provide a concise summary of what students will
learn in the lesson. It explains the unit’s focus,
connection to content, and real world connection.
Biology, Environmental Science, and/or Technology Education
9-12
5-7 days
Students will conduct field studies to analyze Bay health and differentiate between
point and nonpoint solution. Students then analyze existing strategies to reduce
nonpoint solution and develop creative and innovative improvements to established
designs.
It is important to note that for this lesson, students will need to take a field trip to a
watershed to collect water samples or water samples will need to be available to them
for testing. Follow your school’s procedure for organizing field trips.
Organization Posing Challenge:
National Oceanic and Atmospheric Administration(NOAA)
Challenge Title:
NOAA Design Challenge
Challenge Description:
Challenge:
State the real-world challenge students will develop
solutions for.
The purpose of the NOAA Design Challenge is for students to research and design
the most effective strategy for preventing or removing nonpoint source pollution from
the water of the Bay or the streams that flow into it.
Award: Finalists will present to the Chesapeake Bay Program Management Board
who will select the winning team. The names of the winning team will be displayed on
a NOAA Chesapeake Bay Interpretive Buoy System (CBIBS) buoy.
Page 1 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Background Information
Nonpoint source pollution occurs when rain runs off farmland, city streets,
construction sites, and suburban lawns, roofs and driveways and enters our
waterways. This runoff often contains harmful substances such as toxics, excess
nutrients and sediments. It is called nonpoint source pollution because it does not
come from a single source, or point, such as a sewage treatment plant or an industrial
discharge pipe.
Background Information:
Identify information or resources that will help
teachers understand and facilitate the challenge.
Students will first need to develop an understanding of the Chesapeake Bay and the
nutrients, sediments, and toxics issues in the Bay and its watershed. This
understanding will be developed, in part, by students exploring data from NOAA
CBIBS, the National Estuarine Research Reserve System, and Maryland Eyes on the
Bay monitoring platforms.
Students will then localize that knowledge by exploring nearby sources of point and
nonpoint source pollutants entering the Bay or their local waterway and ground
truthing that assessment through the hands-on collection of data. Students will also
explore existing strategies for removing and/or preventing nutrients, sediment and
toxics from entering the Bay.
After developing an understanding of the excess nutrient, sediment and toxics
problem and existing strategies for addressing these problems, students will apply
what they have learned to the design of a technology that will remove or prevent
these pollutants from impacting the Chesapeake Bay system. In addition, students
could consider the cost effectiveness and community impact of their proposed
solution.
STEM Specialist Connection:
Describe how a STEM Specialist may be used to
enhance the learning experience. STEM Specialist
may be found at http://www.thestemnet.com/
STEM Specialists can be used to provide feedback to students proposed design
solutions.
Page 2 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Background Information
 A variety of indicators are used to assess the health of the Chesapeake Bay.
Enduring Understanding:
 Technological solutions can reduce impacts of human activities on natural
Identify discrete facts or skills to focus on larger
concepts, principles, or processes. They are
systems.
transferable - applicable to new situations within or
 Engineers analyze designs to identify shortcomings and opportunities for
beyond the subject.
innovation.
1. How is the health of an aquatic ecosystem defined?
Essential Questions:
2. What factors impact the health of an aquatic ecosystem?
Identify several open-ended questions to provoke
3. How is watershed health linked to the health of an aquatic ecosystem?
inquiry about the core ideas for the lesson. They are
4. How can the health of an aquatic ecosystem be maintained or restored?
grade-level appropriate questions that prompt
5. How does a design brief aid in solution development?
intellectual exploration of a topic.
6. How does reverse engineering connect to scientific innovations?
Students will be able to:
 assess Bay health.
Student Outcomes:
Identify the transferable knowledge and skills that
 differentiate between point and nonpoint source pollution.
students should understand and be able to do when
 evaluate existing technologies and strategies designed to reduce nonpoint
the lesson is completed. Outcomes must align with
source pollution.
but not limited to Maryland State Curriculum and/or
national standards.
 develop a design brief describing proposed improvements to established
solutions.
Audience:
☒Peers
☒Experts /
Product, Process, Action, Performance,
etc.:
Practitioners
Students will use reverse engineering to assess existing
Identify what students will produce to
☒Teacher(s)
technologies and strategies to reduce nonpoint source pollution
demonstrate that they have met the challenge,
and
develop
an
engineering
design
brief
to
outline
a
plan
to
☐School
learned content, and employed 21st century
improve
upon
established
solutions.
Community
skills. Additionally, identify the audience they will
present what they have produced to.
☐Online
Community
☐Other______
Page 3 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Background Information
Next Generation Science Standards:
HS. Human Sustainability
HS-ESS3-4 Evaluate or refine a technological solution that reduces impacts of
human activities on natural systems.
HS. Engineering Design
HS.ETS1-3 Evaluate a solution to a complex real-world problem based on
prioritized criteria and trade-offs that account for a range of constraints,
including cost, safety, reliability, and aesthetics as well as possible social,
cultural, and environmental impacts.
Standards Addressed in the Unit:
Identify the Maryland State Curriculum Standards
addressed in the unit.
Common Core Reading in Science and Technical Subjects:
RST.11-12.7 Integrate and evaluate multiple sources of information presented in
diverse formats and media in order to address a question or solve a problem.
RST.11-12.9 Synthesize information from a range of sources into a coherent
understanding of a process, phenomenon, or concept, resolving conflicting
information when possible.
Common Core Writing in Science and Technical Subjects:
WHST.11-12.2 Write informative/explanatory texts, including the narration of historical
events, scientific procedures/experiments, or technical processes.
Suggested Websites:
Suggested Materials and Resources:
Identify materials needed to complete the unit. This
includes but is not limited to websites, equipment,
PowerPoints, rubrics, worksheets, and answer keys.
Resources
 Chesapeake Bay Program – good general information about the Bay and its stressors
 Governor’s Explore and Restore Your Schoolshed initiative
 Governor’s Stream Restoration Challenge
Monitoring
 NOAA Chesapeake Bay Interpretive Buoy System
 GLOBE Program (Global Learning and Observation to Benefit the Environment) –
Page 4 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Background Information



classroom learning activities related to water quality investigations, including a
lesson on practicing hydrology testing protocols, recommended before using in
the field.
NERRS System Wide Monitoring Program
Eyes on the Bay
Maryland StreamHealth
Funding
 Chesapeake Bay Trust: mini-grant program -- funding to help support projects
Examples of Existing Technologies
 Floating wetland:
o http://www.biohabitats.com/projects/baltimore-healthy-harbor/
o http://www.healthyharborbaltimore.org/whats-happening-now/inner-harborliving-laboratory
 Algae Scrubber:
o http://www.chesapeakequarterly.net/V08N1/main1/
o http://naldc.nal.usda.gov/download/49823/PDF
 Woodchips:
o Bioreactor chips away at nitrogen running off farm fields
o Mid-Shore Riverkeepers - Agricultural Outreach and Remediation
o On-farm treatment of dairy soiled water using aerobic woodchip filters
o Filter Media for Nutrient Removal in Natural Systems and Built Environments: II
– Design and Application Challenges
 Bioretention and Forests (using plants to manage and filter rainwater runoff):
o Rain gardens, Rainscapes and Rainscaping
o Forests as water filters and Forest buffers
 Wetlands:
o http://chesapeakebay.noaa.gov/wetlands
o http://water.epa.gov/type/wetlands/index.cfm
o http://www.fws.gov/chesapeakebay/wetlands.htm
o http://estuaries.noaa.gov/
Page 5 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Background Information
Materials (rubrics, worksheets, PowerPoints, answer keys, etc.):
 Chesapeake Bay Note Sheet
 Presentation Rubric
 Explanatory Writing Rubric
 Point and Nonpoint Source Pollution homework
 Design Brief
Page 6 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Lesson 1 of 2
Lesson Overview: Students conduct research and engage in field studies to develop and understanding of Bay health.
Duration: 2-3 days
Learning Experience
5E Component
Identify the 5E component
addressed for the learning
experience. The 5E model
is not linear.
Details
☐Extension
Preparation:
Write the following questions on the board:
 How is the health of an aquatic ecosystem defined?
 What factors impact the health of an aquatic ecosystem?
 How is watershed health linked to the health of an aquatic ecosystem?
 How can the health of an aquatic ecosystem be maintained or
restored?
☐Evaluation
Divide the class into teams of four – five students.
☒Engagement
☐Exploration
☐Explanation
Facilitation of Learning Experience:
As students enter the class, have them sit in their assigned teams. Each team
will brainstorm answers to the questions written on the board relying solely on
their collective prior knowledge. Teams will record answers to the questions.
Allow approximately five minutes for brainstorming. Have each team share
their answers. Facilitate class discussion as teams reveal their responses. Do
not confirm correct answers or provide guidance for incorrect answers.
Students will conduct research to obtain in depth answers to questions.
Transition:
Inform students that they will work in their teams to conduct research to obtain
in-depth answers to the questions on the board.
Science and Engineering
Practices
☒Asking questions (for
science) and defining
problems (for engineering)
☐Developing and using
models
☐Planning and carrying out
investigations
☐Analyzing and interpreting
data
☐Using mathematics and
computational thinking
☐Constructing explanations
(for science) and designing
solutions (for engineering)
☐Engaging in argument from
evidence
☐Obtaining, evaluating, and
communicating information
Page 7 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Learning Experience
5E Component
Identify the 5E component
addressed for the learning
experience. The 5E model
is not linear.
☐Engagement
☒Exploration
☐Explanation
☐Extension
☐Evaluation
Details
Science and Engineering
Practices
Materials:
 Students will need access to computers or mobile devices to conduct
research.
 Chesapeake Bay Note Sheet
 Presentation Rubric
 Explanatory Writing Rubric
☒Asking questions (for
science) and defining
problems (for engineering)
Preparation:
Prepare copies of the Chesapeake Bay Note Sheet for each student or have
note sheet available for students to access electronically. Provide each
student with a copy of the presentation rubric.
☐Planning and carrying out
investigations
Facilitation of Learning Experience:
In teams, students will conduct research to answer the questions from the
engagement portion of the lesson. Student teams will prepare a creative
presentation to share the information collected and conclusions they made
regarding the health of the Bay with the class.
☐Using mathematics and
computational thinking
As students present, capture key points for each question on the board. After
student presentations, address any misconceptions.
Transition:
Inform students that they will take a trip to their local watershed to assess the
health of the watershed. Provide students with an overview of the tests they
will conduct and an overview of how to prepare for a field study for them to
review.
☐Developing and using
models
☒Analyzing and interpreting
data
☒Constructing explanations
(for science) and designing
solutions (for engineering)
☐Engaging in argument from
evidence
☒Obtaining, evaluating, and
communicating information
Page 8 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Learning Experience
5E Component
Identify the 5E component
addressed for the learning
experience. The 5E model
is not linear.
Details
Science and Engineering
Practices
* If the class is unable to a take a field trip. Inform the class that they will
assess the health of the Chesapeake Bay using Bay monitoring websites.
☐Engagement
☒Exploration
☐Explanation
☐Extension
Field Study:
Students will participate in a field study to assess the health of a local
watershed. Resources to facilitate biological assessment, chemical water
quality testing, and stream corridor assessment are listed below. Use these
resources to facilitate watershed studies and adhere to your school system’s
field trip policy. Students will need time to analyze collected data.

☐Evaluation


Maryland Streams (Teaching Resources) – Maryland Department of
Natural Resources:
http://dnr.state.md.us/cin/explorerestoreschoolshed/teacher_resources.
asp
Bridging the Watershed – Alice Ferguson Foundation:
http://fergusonfoundation.org/bridging-the-watershed/
http://www.nps.gov/asis/forteachers/upload/watershed-watchdogslesson-plan.pdf
Watershed Watchdogs – Monitoring Costal Bay Health through
Bioinventory and Monitoring
http://www.nps.gov/asis/forteachers/upload/watershed-watchdogslesson-plan.pdf
Students will use collected data to write an explanatory text describing the
health of the watershed they assessed and the implications of their findings
on overall Bay health. Use the Explanatory Writing Rubric to evaluate student
☒Asking questions (for
science) and defining
problems (for engineering)
☐Developing and using
models
☒Planning and carrying out
investigations
☒Analyzing and interpreting
data
☐Using mathematics and
computational thinking
☒Constructing explanations
(for science) and designing
solutions (for engineering)
☐Engaging in argument from
evidence
☒Obtaining, evaluating, and
communicating information
Page 9 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Learning Experience
5E Component
Identify the 5E component
addressed for the learning
experience. The 5E model
is not linear.
Details
Science and Engineering
Practices
work.
Alternative Learning Experience:
In the event that an in person field study cannot be conducted, students can
use Bay monitoring sites to collect data regarding Bay health. Sites that can
help facilitate studies include:
 Chesapeake Bay Interpretive Buoy System – Data in the Classroom
http://buoybay.noaa.gov/investigations/data-classroom
 Eyes on the Bay
http://mddnr.chesapeakebay.net/eyesonthebay/
 National Estuarine Research Reserve System System-Wide Monitoring
Program
http://nerrs.noaa.gov/RCDefault.aspx?ID=18
 Maryland Stream Health
http://www.streamhealth.maryland.gov/map.asp
 Chesapeake Bay Report Card (2013)
http://ian.umces.edu/pdfs/ian_report_card_447.pdf
 Integration & Application Network
http://ian.umces.edu/ecocheck/report-cards/chesapeakebay/2013/summaries/
Have students analyze key indicators of Bay health (dissolved oxygen,
nitrogen, phosphorus, etc.) over time. Students will write an explanatory text
describing how and why Bay health has changed over the years. Use the
Explanatory Writing Rubric to evaluate student work.
Transition:
Ask students what did their studies reveal about how pollution impacts the
Page 10 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Learning Experience
5E Component
Identify the 5E component
addressed for the learning
experience. The 5E model
is not linear.
Details
Science and Engineering
Practices
health of the Bay? Engage students in discussion around the question. Inform
students that for homework, they will review point and nonpoint source
pollution and their impacts on Bay health. Provide each student with a copy of
the homework assignment to complete.
Page 11 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Lesson 2 of 2
Lesson Overview: Students will use reverse engineering and the engineering design process to improve upon existing
solutions to reduce nonpoint source pollution.
Duration: 3-4 days
Learning Experience
5E Component
Identify the 5E
component addressed
for the learning
experience. The 5E
model is not linear.
☒Engagement
☐Exploration
☐Explanation
☐Extension
☐Evaluation
Details
Preparation:
Draw a Venn diagram on the board labeling one side point pollution and the other
nonpoint source pollution.
Facilitation of Learning Experience:
Briefly review point and nonpoint source pollution by calling students to the board to
complete the Venn diagram using information from their homework assignment
(additional class time may need to be allocated to review point and nonpoint source
pollution if students did not complete the homework assignment.) Confirm correct
answers and provide guidance for incorrect answers. Engage the class in a brief
discussion about the impacts of nonpoint source pollution on Bay health.
Transition:
Students will work in teams assigned earlier in the lesson to evaluate existing
technologies and strategies designed to prevent or reduce nonpoint source pollution.
Science and
Engineering
Practices
☐Asking questions
(for science) and
defining problems
(for engineering)
☐Developing and
using models
☐Planning and
carrying out
investigations
☐Analyzing and
interpreting data
☐Using
mathematics and
computational
thinking
☐Constructing
explanations (for
science) and
Page 12 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Learning Experience
5E Component
Identify the 5E
component addressed
for the learning
experience. The 5E
model is not linear.
Details
Science and
Engineering
Practices
designing
solutions (for
engineering)
☐Engaging in
argument from
evidence
☒Obtaining,
evaluating, and
communicating
information
☐Engagement
☐Exploration
☐Explanation
☐Extension
☒Evaluation
Materials:
 Design Brief Worksheet
 Engineering Design Process PowerPoint
 Engineering Design Process Overview
 Engineering Design Process Planning Guide
☒Asking questions
(for science) and
defining problems
(for engineering)
Preparation:
For this learning experience, students will use reverse engineering to innovate solutions
to an existing problem. Students will develop design briefs and propose solutions to the
problem. If students are not familiar with the engineering design process, you can use
the Engineering Design Process PowerPoint, Overview, and Planning Guide to review
concepts with students.
☒Planning and
carrying out
investigations
Students will need copies of the design brief worksheet and access to the internet to
conduct research.
☒Developing and
using models
☒Analyzing and
interpreting data
☒Using
mathematics and
Facilitation of Learning Experience:
Page 13 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Learning Experience
5E Component
Identify the 5E
component addressed
for the learning
experience. The 5E
model is not linear.
Details
Inform students that they will work in teams to evaluate existing technological solutions
to reduce nonpoint source pollution from the Bay. Students will then develop a plan to
improve their assigned strategy. This is known as reverse engineering, the process of
analyzing the workings of a technological solution and/or strategy in detail with the
intent to understand its function and purpose. Engineers use information gathered to
construct new and improved products and/or strategies.
Assign each team an existing strategy (see below).




Team 1: Floating wetland:
o http://www.biohabitats.com/projects/baltimore-healthy-harbor/
o http://www.healthyharborbaltimore.org/whats-happening-now/innerharbor-living-laboratory
o http://www.conbio.org/images/content_about_scb/FloatingWetlandsArticle
.pdf
Team 2: Algae Scrubber:
o http://www.chesapeakequarterly.net/V08N1/main1/
o http://naldc.nal.usda.gov/download/49823/PDF
Team 3: Woodchips:
o Bioreactor chips away at nitrogen running off farm fields
o Mid-Shore Riverkeepers - Agricultural Outreach and Remediation
o On-farm treatment of dairy soiled water using aerobic woodchip filters
o Filter Media for Nutrient Removal in Natural Systems and Built
Environments: II – Design and Application Challenges
Team 4: Bioretention and Forests (using plants to manage and filter rainwater
runoff):
o Rain gardens, Rainscapes and Rainscaping
o Forests as water filters and Forest buffers
Science and
Engineering
Practices
computational
thinking
☒Constructing
explanations (for
science) and
designing
solutions (for
engineering)
☐Engaging in
argument from
evidence
☒Obtaining,
evaluating, and
communicating
information
Page 14 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Learning Experience
5E Component
Identify the 5E
component addressed
for the learning
experience. The 5E
model is not linear.
Details
Science and
Engineering
Practices
More than one team can be assigned to a strategy. Teams must apply scientific
knowledge and engineering design practices to improve their assigned strategy.
Provide each team a copy of the design brief worksheet or have it available for students
to access electronically. Allow student time to conduct research, brainstorm solutions,
and complete their design brief.
☐Engagement
☐Exploration
Preparation:
If time allows, students should present their design briefs to STEM Specialists to
receive feedback and modify their designs. STEM Specialists can be found at
www.theSTEMnet.com. Send invitations to Specialists at least two weeks in advance.
☐Explanation
☐Extension
☒Evaluation
Facilitation of Learning Experience:
Students will present their design brief to the class or STEM Specialists. Students can
modify their designs based on feedback. Collect and review student design briefs.
Students can submit their design briefs to STEMChallenge@MBRT.org. Submissions
must include the school, teacher name, and name of students. All students who submit
solutions will be acknowledged by the Maryland Business Roundtable for Education
(MBRT). Finalists will have the opportunity to present their design solutions to the
Chesapeake Bay Program Management Board who will select
☐Asking questions
(for science) and
defining problems
(for engineering)
☐Developing and
using models
☐Planning and
carrying out
investigations
☐Analyzing and
interpreting data
☐Using
mathematics and
computational
thinking
☐Constructing
explanations (for
Page 15 of 26
Innovating Solutions to Nonpoint Source Pollution Using Reverse Engineering
NOAA Design Challenge
Learning Experience
5E Component
Identify the 5E
component addressed
for the learning
experience. The 5E
model is not linear.
Details
Science and
Engineering
Practices
science) and
designing
solutions (for
engineering)
☐Engaging in
argument from
evidence
☒Obtaining,
evaluating, and
communicating
information
Page 16 of 26
Chesapeake Bay Note Sheet
Name:
Name of Team Members:
Date:
Class:
Directions: Work with your team members to conduct research to answer the questions
in the table. Use the table below to capture notes and site sources. Consult several
reputable sources. Suggested sources include:
 Chesapeake Bay Program: www.chesapeakebay.net
 Eyes on the Bay: mddnr.chesapeakebay.net/eyesonthebay
 Maryland Stream Health: http://www.streamhealth.maryland.gov
 Chesapeake Bay Interpretive Buoy System: buoybay.noaa.gov
 Healthy Watersheds: http://water.epa.gov/polwaste/nps/watershed/index.cfm
Questions
How is the
health of an
aquatic
ecosystem
defined?
Justify your
answer with
several
supporting facts.
Notes
Source
Chesapeake Bay Note Sheet
Questions
Notes
Factor
What factors
impact the
health of an
aquatic
ecosystem?
Identify several
factors and the
positive and
negative effects
for each
identified factor
Source
Impact
(Positive and
Negative)
Chesapeake Bay Note Sheet
Questions
How is
watershed
health linked to
the health of an
aquatic
ecosystem?
Justify your
answer with
several
supporting facts.
Notes
Source
Chesapeake Bay Note Sheet
Questions
How can the
health of an
aquatic
ecosystem be
maintained or
restored?
Notes
Maintaining the Health
Restoring the Health
of an Aquatic
of an Aquatic
Ecosystem
Ecosystem
Source
Chesapeake Bay Note Sheet
Questions
Is the
Chesapeake
Bay Healthy?
Justify your
answer with
several
supporting facts.
Notes
Source
Point and NonPoint Pollution
Name:
Date:
Class:
1. Complete the venn diagram below comparing and contrasting point and nonpoint source pollution.
Point Pollution
Nonpoint Pollution
Point and NonPoint Pollution
2. Summarize how nonpoint source pollution impacts the health of the Chesapeake Bay.
Design Brief
Reducing Nonpoint Source Pollution in the Bay
Overview:
Engineers work in teams to improve and refine solutions to existing problems for clients.
For this learning experience, your client is the National Oceanic and Atmospheric
Administration (NOAA). Your team has been charged to evaluate an existing
technological solution to reduce nonpoint source pollution from the Bay and then
develop a plan to improve your assigned solution. You will submit your solutions to
NOAA.
Directions:
Complete the table below to develop your written plan to reduce nonpoint source
pollution in the Chesapeake Bay.
Client
Designers
Insert the name of all of team
members.
Problem Statement
Describe the problem you are
addressing. Making something
better, faster, cheaper, or more
efficient should be a part of your
problem statement.
NOAA
Design Statement
Describe what your team will
improve to your assigned
technological solution. Explain
why your improvement will help
to better reduce nonpoint
source pollution in the Bay.
Constraints
Identify limitations of your
design. Constraints can include
economic, environmental,
social, political, ethical, health,
safety, etc.
Proposed Solution
Describe your team’s proposed
solution. Your team should
brainstorm multiple ideas and
analyze the pros and cons for
each solution before selecting
one. Include technical sketches
and other resources to support
your proposed solution.
References
Cite all sources used for this
project.