Colorado Agriscience Curriculum
Section: Plant & Soil Science
Unit: Soil Management
Lesson Title: Lesson 9: Home site evaluations
Colorado Agricultural Education Standards:
Standard 10.9 The student will demonstrate an understanding of soil fertility and its effect on crop production.
Enabler10.9.13 Evaluate a home site
Colorado Science Standards:
Standard 7.0 Students know and understand common connections between scientific disciplines as well as connections between science and other academic areas.
Competency 7.01 Use graphs, equations, or other models to analyze systems involving change and constancy.
Student Learning Objectives (Enablers)
As a result of this lesson, the student will:
1. Understand terms of soil limitations
2. Be able to read charts and analyze soil for the nine soil and site properties to be analyzed for a home site.
Time: Instruction time for this lesson: 50 minutes.
Resources:
Land Judging in Colorado. Colorado State University, Dept. of Soil and Crop Sciences, Ft. Collins, CO 2004.
Tools, Equipment, and Supplies
Interest Approach Handout
Home Site Evaluation Handout
Home Site Evaluation for Dream Home Handout
Colorado Land Classification Manual Home Site Evaluation Chapter
(found at the end of this lesson)
Highlighters for each student
Writing surface
Writing utensils
Color overheads/Overhead projector/Computer with Powerpoint and projector and sound
Interest Approach
Begin a discussion about building a home. Break students up into small groups and have them brainstorm what needs to be done before they get to build a home. This brainstorm session is designed to get them thinking about soil properties that must be analyzed before a home can be built.
***Congratulations!!! You have just been given a free house! The house is 3200 square feet and can be built wherever you please. But, in order to get the free house you must do some analyzing as you pick the site. We are going to work in groups of three today. Your group will (in theory) own the home. When I say “Build it” I want you to get into your groups and work together to come up some the answers to these questions. You have 5 minutes to complete the exercise. Ready, “BUILD IT.”
Hand out Interest Approach Handout. Offer guidance and give a warning at one minute. And then call for the groups to finish, and share their ideas.
***Ok you have one minute left. Time is up. Let’s hear your group ideas.
***Those are great ideas. I want you to hold onto the papers and we will come back to them in a little while.
INTEREST APPROACH HANDOUT
Group Name(s)______
Congratulations your group has just been given a free home! Your group needs to come up with some answers before we can start building. Answer the questions as specific as possible. Do not let the suggestions limit your ideas!
1. Where do you want your house? Be specific—in the country, city, on the water, in the desert, pick an exact location.
2. What style of house do you want? Two story, one story, basement, above ground, walk out basement?
3. How will you deal with the sewer waste?
4. What do you want the outside to look like? Lawns, extensive landscaping, xeriscape, high water use, low water use?
5. What do you know about the soil where you want to build this home?
6. What types of soils might give your ideas listed above trouble?
Summary of Content and Teaching Strategies
Objective 1. Understand the terms of soil limitations
Transition into objective one, by asking some questions.
***When we worked on our dream home projects each group came up with some items that might restrict where their home gets built, or what type of home they can build. Such as can you have a basement on an ocean front property? No probably not, unless you want a swimming pool in the basement, because of internal seepage from the ocean.
Take our your notes. There are nine factors of soil we are going to analyze before we can build a home. There are many more, but these are the beginning stages to a home site evaluation.
*** We are going to analyze different soil situations a little bit later, but first we need to understand all the areas that we will look at.
***The first area we look at is SURFACE TEXTURE
Hopefully students already understand texture, if not it must be taught, if they do, then a little review is good.
***Who can tell me what surface texture is? Good Job. You are right on track. Now why would surface texture affect our home site?
Show slide #2
***All soils have a certain feel to them and based on their make-up sand, silt, and clay, they are classified as fine, medium, and coarse. Surface soil texture is a criterion in evaluating suitability for building foundations and landscaping, but is not a criterion for sewage lagoons or septic systems as they are dug below the surface.
Show slide #3
***The next area to be analyzed is PERMEABILITY or internal soil drainage. What areas do you think internal drainage affects? Remember internal drainage is rated as to how fast water moves through the soil. The ratings are very slow, slow, moderate, and rapid.
Permeability is an important factor in deciding between a septic tank or sewage lagoon for effluent disposal. It is generally not considered a criterion for building foundations.
Show slide #4
***SOIL DEPTH must be considered next. Soil depth refers to the vertical depth of surface soil plus subsoil plus any underlying material to a consolidated material that would restrict root penetration or inhibit excavation. Consolidated material may be either geologic, such as shale bedrock, or pedogenic, such as caliche. This would be factor for basements and determining the style of the house. We must decide if our soil depth is very shallow, shallow, moderately deep, deep, or very deep.
Show slide #5
***All of you that wanted to build your house on a hillside or into a hill this next one is for you. The next factor that must be considered is SLOPE. Slope refers to the inclination of the soil surface, and has a direct influence on site drainage. Our slopes can be broken down into the following classifications; Gentle, moderate, Strong, Steep, and Very Steep.
Show slide #6 and 7
***SOIL EROSION is our next factor. You guys should be experts in the area of soil erosion by now. The removal of topsoil, from wind and water will cause many problems for a homeowner. From the loss of topsoil, airborne soil particles, soil piling up in areas not wanted, and severe rills and gullies create problems for septic systems, landscaping and other uses. Our site must be given a soil erosion rating of; slight, moderate, severe, very severe.
Show Slide #8
***After we analyze erosion, we move to SURFACE RUN-OFF. Where will this become a problem? Surface run-off is a problem when water runs off of the surface before it goes into the soil. We are most worried about the water running off from above and into our home. Our foundations would then be in jeopardy. We decide if our potential home site has a surface run-off factor of; slow, moderate, or rapid.
Show slide #9
***SHRINK-SWELL is another criteria. Soil will shrink and swell depending on the amount of what in it?????? You are right, clay is our big factor here. Clay with smectite in it will trap water molecules. As they take on these water molecules, they swell to many times their original size, shrinking back to their original size when the water is removed. These shrinking and swelling cycles cause significant damage to building foundations, roads, sidewalks and other structures. The horizon having the most clay should be considered when determining shrink-swell limitations. Based on the amount of clay we classify the soils as slight, moderate, and severe.
Show slide #10
***When I say “water table” what do you think about? Water table refers to how far it is to available water. A shallow water table will cause many problems for a home site. When looking at water table you should look at the time of the year when the water table is the closest to the surface. Water table depth can be broken into the following areas: slight, moderate, and severe.
Show slide #11
***FLOODING is the final area to be evaluated. How many of you put your homes, near the water? This should be a concern for you. You must also look at the home site as if were to become urbanized and the area becomes “sealed” with asphalt or concrete, surface runoff increases dramatically. If the urbanized area is in close proximity to a floodplain, the flood hazard may also increase. Landscape position and proximity to streams are flood hazard indicators. Our ratings are; None, Rare, and Frequent.
***We covered a lot of information there. Most of them nine areas are self explanatory. I would like you to make sure you have a good understanding of each area.
Use the crayon moment to solidify what was covered.
***Take a moment and go back through the nine areas and draw a picture, with these crayons or draw an icon for each one that would help you remember them and what they are.
Objective 2. Be able to read charts and analyze soil for the nine soil and site properties to be analyzed for a home site.
Transition into the next objective. Have the land classification sheets ready to pass out. You can add the home site evaluation handout to the packet or hand out separately.
***Now that we know the soil properties to look at before we pick out our free home, let’s take a sample soil evaluation and fill it out using the tables provided.
Hand out the packets and the highlighters.
***I am handing out your packet of tables and a highlighter. We are going to go through this first one together. I encourage you to highlight the portions of the tables that tell you the limitations.
Remember if the chart says the soil has a severe limitation, then that trait of the soil is bad for your intended use. Also, the answers usually are at the end of each section.
Power point slides #12 through 20
Using the answer key, the hand out, and the power point slides, walk the students through each table. Show them how to pull information from each table.
Explain that in a contest situation they would have to make their own choices for the left hand column.
Once the sheet is filled out the students will need help with the Final Evaluation on the bottom.
***You did a great job following along with all of those examples. This is the most important part. Let’s do the final evaluation. We have talked about a chain being only as strong as the weakest link, well, a soil is only as good as its limitations. If a soil has just one limitation marked very severe for any home site application (building foundation, landscaping, septic systems, or sewage lagoon) then that application is marked very severe on the bottom of the card.
Look at the card from the top down and do one column at a time. Start with very severe, if there are any “very severe’s” then mark that at the bottom. If there are not any, then start with severe and do the same thing. Do this for each application.
In our example, the site wasn’t good for much at all. It had severe limitations for foundations and landscaping, and very severe for septic systems, and sewage lagoons.
SITE OR SOIL
PROPERTY / LIMITATION
RATING / BUILDING
FOUNDATIONS / LANDSCAPING / SEPTIC
SYSTEMS / SEWAGE
LAGOONS
SURFACE TEXTURE
FINE
MEDIUM
COARSE / Slight
Moderate
Severe /
/
PERMEABILITY
VERY SLOW
SLOW
MODERATE
RAPID / Slight
Moderate
Severe
Very severe /
/
/
SOIL DEPTH
VERY SHALLOW
SHALLOW
MODERATELY DEEP
DEEP
VERY DEEP / Slight
Moderate
Severe
Very severe /
/
/
/
SLOPE
LEVEL-GENTLE
MODERATE
STRONG
STEEP
VERY STEEP / Slight
Moderate
Severe
Very severe /
/
/
/
EROSION
NONE-SLIGHT
MODERATE
SEVERE
VERY SEVERE / Slight
Moderate
Severe /
/
/
/
SURFACE RUNOFF
SLOW
MODERATE
RAPID / Slight
Moderate
Severe /
/
/
SHRINK-SWELL
LOW
MODERATE
HIGH / Slight
Moderate
Severe /
/
/
WATER TABLE
_____ INCHES / Slight
Moderate
Severe /
/
/
/
FLOODING
NONE
OCCASIONAL
FREQUENT / Slight
Moderate
Severe /
/
/
/
FINAL EVALUATION
All properties none-slight
One or more moderate
One or more severe
One or more very severe / Slight
Moderate
Severe
Very Severe / (3 PTS)
/ (3 PTS)
/ (3 PTS)
/ (3 PTS)