3/7/2011
Watershed Segment Map
This map is coded by colors and each color corresponds to a segment (the number in green). This segment number will then allow you to choose the
appropriate nitrogen or phosphorous delivery ratio and appropriate nitrogen or phosphorous edge of segment ratio from the table listed on the second
page. For example, if your property is in Bedford, you would be in segment 90 which would give a nitrogen delivery ratio of 0.897 and a nitrogen
edge of segment ratio of 15 % to 45% depending on the tillage practice.
3/7/2011
Delivery and EOS Ratios
Watershed
Segment
Nitrogen
Delivery
Ratio
10
20
30
40
50
60
70
80
90
100
110
120
140
160
175
180
210
450
470
700
710
720
730
740
750
800
0.474
0.495
0.733
0.871
0.836
0.93
0.941
0.951
0.897
0.88
0.961
0.98
0.99
0.583
0.7
0.819
0.72
1
1
0.7
0.97
0.891
0.683
0.749
0.627
1
Nitrogen EOS Ratio (see Notes 1 & 2)
Conventional Conservation
Till
Till
Hay Pasture
36%
38%
43%
42%
50%
55%
45%
32%
45%
35%
31%
29%
30%
33%
33%
34%
46%
30%
25%
40%
28%
27%
23%
21%
47%
48%
29%
31%
31%
38%
38%
31%
45%
25%
34%
29%
22%
21%
22%
28%
22%
38%
33%
22%
17%
35%
21%
21%
22%
17%
33%
34%
89%
34%
78%
60%
97%
78%
86%
75%
49%
32%
27%
20%
22%
59%
29%
58%
40%
16%
23%
37%
15%
16%
43%
50%
38%
34%
15%
16%
16%
12%
18%
15%
13%
10%
15%
12%
10%
9%
9%
23%
20%
9%
10%
9%
6%
13%
9%
9%
11%
12%
10%
9%
Watershed
Segment
Phosphorus
Delivery
Ratio
10
20
30
40
50
60
70
80
90
100
110
120
140
160
175
180
210
450
470
700
710
720
730
740
750
800
0.436
0.436
0.436
0.436
0.436
0.436
0.436
0.436
0.436
0.436
0.436
0.436
0.436
0.67
0.67
0.67
0.669
1
1
0.436
0.436
0.436
0.67
0.67
0.67
1
Phosphorus EOS Ratio (see Notes 1 & 2)
Conventional Conservation
Hay Pasture
Till
Till
10%
4%
4%
15%
13%
7%
5%
16%
11%
6%
7%
16%
12%
10%
7%
12%
15%
6%
14%
18%
11%
4%
16%
15%
27%
7%
12%
13%
12%
7%
7%
10%
11%
4%
12%
15%
8%
3%
5%
12%
9%
5%
5%
10%
8%
3%
4%
9%
25%
10%
7%
9%
32%
27%
7%
23%
5%
5%
6%
20%
9%
7%
4%
9%
11%
7%
7%
10%
5%
2%
2%
9%
22%
3%
3%
6%
7%
6%
5%
13%
6%
2%
2%
9%
6%
3%
3%
9%
15%
8%
6%
11%
12%
8%
8%
12%
13%
7%
5%
10%
15%
8%
11%
9%
Notes:
1. The portion of nutrient loads leaving a watershed were estimated by adding the manure, fertilizer, air deposition and mineral/residual nutrient inputs for each watershed
and subtracting the estimated crop uptake from the total nutrient inputs. The remaining nutrient loads after crop uptake were then divided by the estimated loads leaving the
watershed to calculate the edge of watershed percents.
2. All calculations based on watershed simulations completed by EPA's Chesapeake Bay Program Office.