|
C.
Soils
Detailed
Soil Mapping
In order to represent some of the important soil features in the watershed,
digital soils data was gathered for all the counties in the watershed and was
complied into one large database. The
digital soil polygon data represented in these maps was created from
digitization of old soil surveys from the 1970s.
The polygon data was then joined with NRCS’s Map Unit Interpretation
Record (MUIR) soils tables. Additional
data was gathered from the Electronic Field Office Technical Guide on the NRCS
webpage. Together these maps and
this soils database represents the best digitally available soils data at this
point. In several years most
counties in
Ohio
should have a comprehensive digital soils file;
SSURGO certified soils.
A large number of soils features such as clay percentage, organic
content, slope, flooding, septic limitations and others are included in this
soils database. Detailed maps and
descriptions have been created for the four major watersheds within the Darby
Creek Watershed; Headwaters of Big Darby, Middle Big Darby, Lower Big Darby, and
Little Darby Creek. Appendixes A,
B,
and C will contain data on highly erodible soils, slope, and prime farmland for
each of the four major watersheds. General
data on highly erodible soils is presented below and in the Agricultural
section, slope data will be presented in the following section on Topography, and prime
farmland in the Agricultural
section.
It is to be noted that not all the data classes were consistent between
counties. For example
Union
County
defines soils not considered prime farmland but in continued agricultural
production as “Farmland of Local Importance” whereas no other county
represents data in this fashion. Another
inconsistency in the methodology of data collection is with the slope data as
one county may define slopes between 15% and 20% as one category but all the
other counties typically define soils in this range between 12% and 18%.
Such inconsistencies were resolved through the assistance of ODNR soil
scientists.
Highly Erodible Soils
The highly erodible factor was derived from soil surveys from each county.
Detailed maps (four) and descriptions of this factor are available in
Appendix A. The following figure
summarizes the erodibility of all soils and the agricultural lands in the entire
Darby Creek Watershed.
|
Figure
5: Darby
Creek
Watershed Erodibility Summary
|
|
Erodibility
|
All
Land (Percent)
|
Only
Agricultural Land (Percent)
|
|
Highly Erodible
|
8.75%
|
6.35%
|
|
Not Highly Erodible
|
59.79%
|
63.90%
|
|
Potentially Erodible
|
30.90%
|
29.47%
|
|
Water and other Soils
|
0.57%
|
0.29%
|
|
Totals
|
100%
|
100%
|
The Upper Big Darby had the most highly erodible soils with
over 14 percent followed by Little Darby with about 9 percent.
Middle Big Darby and Little Darby had the least amount of highly erodible
(See Figure 6). For more detail on
the erodibility of all soils in each watershed listed below, see Appendix
A.
|
Figure
6: Erodibility of Soils by Major Subwatershed
|
|
Subwatershed
|
Highly
Erodible
|
Not
Highly Erodible
|
Potentially
Erodible
|
Water
and Other Soils
|
|
Upper
Big Darby
|
14.20%
|
57.87%
|
27.43%
|
0.50%
|
|
Middle
Big Darby
|
2.05%
|
77.17%
|
20.03%
|
0.75%
|
|
Lower
Big Darby
|
5.25%
|
54.84%
|
38.81%
|
1.10%
|
|
Little
Darby
Creek
|
8.69%
|
57.60%
|
33.53%
|
0.18%
|
 
Back to Table of Contents
| 
