APPENDIX C 

 SIGNIFICANT ENGINEERING SOIL PROPERTIES 



Table C-1 illustrates the type of soil properties that have been 

 estimated for each of the major soils. The column headings are described 

 below: 



Column 1 . Soil Names and Associations in which They Occur. The soils are 

 listed in alphabetical order along with the association numbers in which they 



Column 2. Depth (feet) to Bedrock. The depth in feet from the surface to 

 bedrock is indicated in this column. 



Column 3. Depth (feet) to Seasonal Water Table. This is the depth in feet 

 from the surface to a seasonal high water table. During the year, free water 

 saturates most soils to varying depths. This depth is determined largely by 

 soil color patterns. The duration of the water table at a given level varies 

 with the season and is not considered in this column. 



Column h. Hydrologic Group. Four groups are used in watershed planning to 

 estimate runoff from rainfall. Soil properties are considered that influence 

 the minimum rate of infiltration obtained for a bare soil after prolonged 

 wetting . Dual groups are given for most of the soils that have bedrock 

 within 20 inches of the surface. 



Column 3' Percolation Rate Class. Percolation rate refers to the movement 

 of water through the soil away from the water filled percolation test hole. 

 It is expressed in four classes as follows: 



■n -u -u ■ -1 • 4- Minutes 



Class Probability Per Inch 



Fast 80^ chance that rate will fall < 5 

 Probably fast 50^ chance that rate will ' fail in or 



above 10-20 

 Probably slow 50^ chance that rate will fall in or 



below 10-20 



Slow 80^ chance that rate will fall > 30 



Column 6. Depth (inches) from Surface. Depths from the surface of a repre- 

 sentative profile are given in inches. 



