|
A.
Watershed Features
2.
Gradient
The gradient of the watershed varies greatly from
moderately high in the headwaters of the watershed to low in the midsection of
the watershed. The mainstem of the
Big Darby has an elevation of 1170 feet above sea level at its start in
Logan
County
and an elevation of 643 feet at its mouth in
Pickaway
County. The average gradient of the Big
Darby
Creek
is 6.8 feet per mile. The gradient
of other major Ohio
streams is displayed in Figure 70.
|
Figure
70: Gradient of Selected Ohio
Streams
|
|
Stream
|
Total
Stream Miles
|
Gradient
(Ft/Mile)
|
|
Maumee River
|
105.4
|
1.3
|
|
Stillwater
|
67.2
|
4.2
|
|
Little
Miami River
|
105.5
|
6.5
|
|
Big
Darby
Creek
|
78.7
|
6.8
|
|
Cuyahoga
River
|
100.1
|
7.1
|
Source:
ODNR, Streams
Gazetteer, 2nd Edition, 2001.
Many stream channels through agricultural areas of the
watershed have been straightened and deepened to improve drainage in flat
regions of the watershed. An example
of a stream that has been altered to improve drainage is Flat Branch in
Logan
County
which only falls 21 feet in 4.7 miles. Figure
71 below summarizes the average fall of major streams in the Darby Watershed.
|
Figure
71: Gradient
of Streams in Darby Watershed
|
|
|
Length
|
Elev.
at
|
Elev.
at
|
Av.
Fall
|
|
Stream
Name
|
(miles)
|
Source
|
Mouth
|
Ft
per Mile
|
|
Flat
Branch
|
4.7
|
1,069
|
1,048
|
4.5
|
|
Buck
Run
|
6.8
|
999
|
960
|
5.7
|
|
Little
Darby
Creek
|
69.1
|
1,045
|
820
|
5.9
|
|
Big
Darby
Creek
|
78.7
|
1,170
|
643
|
6.8
|
|
Spring
Fork
|
12
|
1,028
|
941
|
7.2
|
|
Sugar
Run
|
5
|
942
|
903
|
7.8
|
|
Barron
Creek
|
4.8
|
1,003
|
963
|
8.3
|
|
Sugar
Run
|
4.4
|
983
|
944
|
8.9
|
|
Hay
Run
|
3.6
|
1,011
|
977
|
9.4
|
|
Robinson
Run
|
3.2
|
952
|
918
|
10.6
|
|
Prairie
Run
|
2.5
|
988
|
961
|
10.8
|
|
Hellbranch
Run
|
12.8
|
921
|
777
|
11.2
|
|
Springwater
Run
|
0.6
|
775
|
767
|
13.3
|
|
Threemile
Run(Fitzgerald Ditch)
|
5.3
|
972
|
880
|
17.4
|
|
Lake
Run
|
4.1
|
1,081
|
1,008
|
17.8
|
|
Treacle
Creek
|
14.2
|
1,240
|
986
|
17.9
|
|
Proctor
Run
|
6
|
1,125
|
997
|
21.4
|
|
Howard
Run
|
3.2
|
1,079
|
1,005
|
23.1
|
|
Greenbrier
Creek
|
2.6
|
820
|
730
|
34.6
|
|
Georges
Creek
|
0.5
|
745
|
725
|
40.0
|
|
Little
Darby
Creek
(Logan
Co.)
|
4.5
|
1,232
|
1,047
|
41.1
|
|
Pleasant
Run
|
8
|
1,340
|
1,004
|
42.0
|
|
Jumping
Run
|
2.7
|
1,180
|
1,064
|
43.9
|
|
Clover
Run
|
3.8
|
1,250
|
1,037
|
56.1
|
Source:
ODNR, Stream Gazetteer, 2nd Edition,
2001
  
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