Activity 3.4.4 Web Soil Survey

Introduction

The USDA Natural Resources Conservation Service operates a National Cooperative Soil Survey. The survey provides online access to soil data, maps, and information for more that ninety-five percent of the nation’s counties. Although an on-site soils investigation is often needed, the Web Soil Survey information can be useful when researching the existing soil conditions on a site.

In this activity you will use the Web Soil Survey to gather information about the soil conditions on the Keystone Library site.

Equipment

  • Engineering notebook
  • Internet access
  • Pencil
  • Printer
  • USCS Soil Classification Chart
  • Plasticity Chart

Procedure

The following website contains the information necessary to complete the questions below and to research the properties of soil on your site.

Use your engineering notebook to respond to the following questions. Rewrite the question in your notebook.

  1. Start the Web Soil Survey by depressing the START WSS button.
  2. Use the navigation bar to Navigate By…State and County. Define your site as an Area of Interest using the AOI button on the Area of Interest (AOI)tab.

  1. Choose the Soil Data Explorer tab.
  1. Choose the Intro to Soils tab. Research the information to answer the following questions in your notebook.
  • What is soil?
  • What are the four classifications of mineral particles in soil?
  • What other types of matter can be included in soil?
  • How is soil formed?
  • What is a soil scientist?
  • What is a soil survey?
  • What type of information does a soil survey provide for construction engineers?
  1. View the Soil Map (choose the Soil Map tab) and identify the soils that are present on your site by their classification code. Within your design team, assign each of the soil types to a team member for research.
  2. Choose the Soil Data Explorer tab, then choose the Soils Properties and Qualities tab. Search the data and record the following information for your soil in your notebook. Do not change the default values in the navigation bar, but be sure to include information for All Layers (at the bottom of Advanced Options).
  • Liquid Limit
  • Organic Matter
  • Percent Clay
  • Percent Sand
  • Percent Silt
  • Plasticity Index

  1. Fill in the following table to display each soil property for each soil. You will have to calculate the Plastic Limit. Use the USCS Soil Classification Chart and Plasticity Graph, to classify each soil using the USCS classification.

Soil Classification / Liquid Limit (percent) / Organic Matter
(percent) / Percent Clay / Percent Sand / Percent Silt / Plasticity Index / Plastic Limit
PL= LL- PI / USCS Classification
  1. Choose the Suitabilities and Limitations for Use tab.
  • Research the limitations for sanitary facilities on the property. Specifically, research the limitations (if any) for installation of septic tank absorption fields. Record your findings in your notebook.
  • Research the limitation for small commercial buildings. Record your findings in your notebook.
  1. Print out a soils map and create a soils report for your site. The soils report should include your research, the soil classification of each soil, the recommended soil bearing capacity for the site, the suitability of the site for a septic system, and the suitability of the site for development.

Conclusion

  1. How will these findings affect the design and construction of your project on this site?

© 2010 Project Lead The Way, Inc.

Civil Engineering and ArchitectureActivity 3.4.4 Web Soil Survey– Page 1