E) presence ofmanmade structures - Are 

 buildings, dams, levees, roads, or parking lots 



present? 



2) Determine the approximate date when the 

 alteration occurred, if necessary. Check aerial pho- 

 tographs, examine building permits, consult with 

 local individuals, and review other possible sources 

 of information. 



3) Describe the effects on soils. Consider the 



following: 



A) Has the soil been buried? If so, record 

 the depth of fill material and determine whether the 

 original soil was left intact or disturbed. {Note: The 

 presence of a typical sequence of soil horizons or 

 layers in the buried soil is an indication that the soil 

 is still intact; check description in the soil survey 

 repon.) 



B) Has the soil been mixed at a depth 

 below the A-horizon or greater than 10 inches? If 

 so, it will be necessary to examine the soil at a 

 depth immediately below the plow layer or dis- 

 turbed zone. 



C) Has the soil been sufficiently altered 

 to change the soil phase? Describe these changes. If 

 a hydric soil has been drained to some extent, refer 

 to Step 5 below to determine whether soil is effec- 

 tively drained or is still hydric. 



4) Characterize the soils that previously 

 existed at the disturbed site. Obtain all possible evi- 

 dence that may be used to characterize soils that 

 previously occurred on the area. Consider the fol- 

 lowing potential sources of information: 



A) soil surveys - In many cases, recent 

 soil surveys are available. If so, determine the soils 

 that were mapped for the area. If all soils are hydric 

 soils, it is presumed that the entire area had hydric 

 soils prior to alteration. 



B) buried soils - When fill material has 

 been placed over the original soU without physical- 

 ly disturbing the soil, examine and characterize the 

 buried soils. Dig a hole through the fill material 

 until the original soil is encountered. Determine the 

 point at which the original soil material begins. 

 Remove 18 inches of the original soil from the hole 

 and look for indicators of hydric soils immediately 



below the A-horizon and within 6-18 inches 

 (depending on soil permeability and drainage 

 class). Be sure to record the color of the soil 

 matrix, presence of an organic layer, presence of 

 mottles or gleying, and/or presence of iron and 

 manganese concretions. (Note: When the fill mate- 

 rial is a thick layer, it might be necessary to use a 

 backhoe or posthole digger to excavate the soil pit.) 

 If USGS topographic maps indicate distinct varia- 

 tion in the area's topography, this procedure must 

 be apphed in each portion of the area that originally 

 had a different surface elevation. 



C) plowed soils - Determine the depth to 

 which the soil has been disturbed by plowing. 

 Look for hydric soil characteristics immediately 

 below this depth. 



D) removed surface layers - Dig a hole 

 18 inches deep and determine whether the entire 

 surface layer (A-horizon) has been removed. If so, 

 examine the soil immediately below the top of the 

 subsurface layer (B-horizon) for hydric soil charac- 

 teristics. As an alternative, examine an undisturbed 

 soil of the same soil series occurring at the same 

 topographic position in an immediately adjacent 

 undisturbed reference area. Look for hydric soil 

 indicators immediately below the A-horizon and 

 within 18 inches of the surface. Record and use 

 these data to determine the presence of hydric soils 

 in substep 5 below. 



5) Determine whether hydric soils were 

 present at the project area prior to alteration. Exam- 

 ine the available data and determine whether indica- 

 tors of hydric soils were formerly present. If no 

 indicators and/or evidence of hydric soils are 

 found, the original soils are considered nonhydric 

 soils. If indicators and/or evidence of hydric soils 

 are found the hydric soil criterion has been met. 

 Continue to Step 5 if hydrology also was altered. 

 Otherwise, record decision and return to the appli- 

 cable step of the onsite determination method being 

 used. 



Step 5. Determine whether wetland hydrology 

 existed prior to alteration or whether wetland 

 hydrology still exists (i.e., is the area effectively 

 drained?). To determine whether wetland hydrolo- 

 gy still occurs, proceed to Step 6. To determine 

 whether wetland hydrology existed prior to the 

 alteration: 



52 



