Pollutant Load Reductions from Wetland Restoration in Highly Critical Agricultural Subwatersheds
EPA STEPL Model
Subwatershed #3
Watershed
N Load (no
BMP)
lb/year
W1
W2
W3
W4
Total
lb/year
1459.5
815.7
172.5
1233.5
3681.2
Subwatershed #4
Watershed
N Load (no
BMP)
lb/year
W1
W2
W3
W4
Total
P Load (no
BMP)
lb/year
P Load (no
BMP)
P Load (no
BMP)
10.8
237.9
332.2
823.7
815.5
2220.1
BOD Load (no
BMP)
lb/year
57.5
255.6
66.8
183.7
563.5
P Load (no
BMP)
lb/year
90.7
349.4
96.1
19.6
334.6
890.3
BOD Load (no
BMP)
lb/year
lb/year
lb/year
1856.4
619.1
141.2
2105.7
4722.5
1.9
36.8
48.0
110.8
87.5
284.9
179.6
893.4
240.5
645.9
1959.3
Subwatershed #12
Watershed
N Load (no
BMP)
BOD Load (no
BMP)
lb/year
lb/year
Subwatershed #10
Watershed
N Load (no
BMP)
2975.7
1663.2
352.2
4001.1
8992.3
294.4
93.6
20.9
214.6
623.4
5.4
117.0
162.7
401.7
286.0
972.8
W1
W2
W3
W4
Total
lb/year
lb/year
lb/year
W1
W2
W3
W4
W5
Total
BOD Load (no
BMP)
439.7
245.3
50.8
332.8
1068.6
914.8
304.1
69.3
718.3
2006.5
Subwatershed #7
Watershed
N Load (no
BMP)
W1
W2
W3
W4
W5
Total
P Load (no
BMP)
364.6
1827.7
492.9
1993.6
4678.8
BOD Load (no
BMP)
lb/year
29.4
102.4
27.3
5.6
103.5
268.2
183.9
713.7
196.6
40.1
942.2
2076.6
446 acres
Sediment
Load (no
BMP)
t/year
287.9
160.4
32.4
229.0
709.6
195 acres
Sediment
Load (no
BMP)
t/year
206.4
62.7
13.6
156.2
438.9
71 acres
Sediment
Load (no
BMP)
t/year
1.4
25.2
30.7
65.1
64.5
186.9
204 acres
Sediment
Load (no
BMP)
t/year
40.1
157.6
39.6
130.2
367.5
80 acres
Sediment
Load (no
BMP)
t/year
20.8
65.0
16.7
3.4
76.7
182.6
lbs/yr
N Load
Reduction
initial load
new load
load reduc
2447.7
1233.5
1214.2
N Load
Reduction
initial load
new load
load reduc
1288.2
718.3
569.9
N Load
Reduction
initial load
new load
load reduc
686.8
286.0
400.8
N Load
Reduction
initial load
new load
load reduc
1313.4
645.9
667.5
N Load
Reduction
initial load
new load
load reduc
555.8
334.6
221.2
lbs/yr
P Load
Reduction
tons/yr
Sediment
Load
Reduction
735.8
480.7
332.8
229.0
403.0
251.7
P Load
Reduction
408.9
214.6
194.3
P Load
Reduction
197.4
87.5
109.8
P Load
Reduction
379.8
183.7
196.2
P Load
Reduction
164.7
103.5
61.2
Sediment
Load
Reduction
282.7
156.2
126.5
Sediment
Load
Reduction
122.4
64.5
57.9
Sediment
Load
Reduction
237.3
130.2
107.0
Sediment
Load
Reduction
105.9
76.7
29.2
Pollutant Load Reductions from Wetland Restoration in Highly Critical Agricultural Subwatersheds
EPA STEPL Model
Subwatershed #14
Watershed
N Load (no
BMP)
lb/year
W1
W2
W3
W4
Total
lb/year
173.6
853.5
2046.5
1430.1
4503.7
Subwatershed #15
Watershed
N Load (no
BMP)
lb/year
W1
W2
W3
W4
W5
Total
P Load (no
BMP)
lb/year
P Load (no
BMP)
P Load (no
BMP)
103.0
3220.8
163.4
154.3
3172.5
6814.0
BOD Load (no
BMP)
lb/year
249.6
59.2
361.2
3.0
305.9
979.0
P Load (no
BMP)
lb/year
420.1
1744.5
56.8
141.4
1298.2
3660.9
BOD Load (no
BMP)
lb/year
lb/year
lb/year
2062.4
2163.8
1198.2
2.8
4141.9
9569.1
16.7
410.9
22.8
20.6
280.0
751.0
804.9
199.3
1365.7
10.3
1104.7
3484.8
Subwatershed #20
Watershed
N Load (no
BMP)
BOD Load (no
BMP)
lb/year
lb/year
Subwatershed #18
Watershed
N Load (no
BMP)
352.4
1746.0
4228.1
4586.6
10913.1
312.7
301.2
158.1
0.4
356.3
1128.7
50.8
1565.9
79.9
75.2
1006.3
2778.1
W1
W2
W3
W4
W5
Total
lb/year
lb/year
lb/year
W1
W2
W3
W4
W5
Total
BOD Load (no
BMP)
55.6
244.5
496.4
390.7
1187.2
1013.2
1057.4
583.7
1.4
1297.6
3953.3
Subwatershed #16
Watershed
N Load (no
BMP)
W1
W2
W3
W4
W5
Total
P Load (no
BMP)
1637.7
406.8
2807.6
21.1
3498.4
8371.5
BOD Load (no
BMP)
lb/year
132.1
455.6
16.4
38.1
356.5
998.7
853.9
3589.2
116.1
290.3
4143.6
8993.1
501 acres
Sediment
Load (no
BMP)
t/year
38.8
151.0
238.4
270.8
699.0
449 acres
Sediment
Load (no
BMP)
t/year
210.1
184.7
90.8
0.3
247.7
733.5
337 acres
Sediment
Load (no
BMP)
t/year
11.9
225.2
14.1
12.0
196.1
459.3
374 acres
Sediment
Load (no
BMP)
t/year
168.6
38.2
200.3
1.9
213.7
622.7
449 acres
Sediment
Load (no
BMP)
t/year
90.6
247.9
10.2
21.7
247.8
618.2
N Load
Reduction
initial load
new load
load reduc
3073.6
1430.1
1643.5
N Load
Reduction
initial load
new load
load reduc
2655.6
1297.6
1358.0
N Load
Reduction
initial load
new load
load reduc
1771.8
1006.3
765.5
N Load
Reduction
initial load
new load
load reduc
2380.2
1104.7
1275.5
N Load
Reduction
initial load
new load
load reduc
2362.7
1298.2
1064.6
P Load
Reduction
796.5
390.7
405.8
P Load
Reduction
772.4
356.3
416.0
P Load
Reduction
471.0
280.0
191.0
P Load
Reduction
673.1
305.9
367.2
P Load
Reduction
642.2
356.5
285.7
Sediment
Load
Reduction
428.2
270.8
157.4
Sediment
Load
Reduction
485.8
247.7
238.1
Sediment
Load
Reduction
263.2
196.1
67.0
Sediment
Load
Reduction
409.0
213.7
195.3
Sediment
Load
Reduction
370.3
247.8
122.5
Pollutant Load Reductions from Wetland Restoration in Highly Critical Agricultural Subwatersheds
EPA STEPL Model
Subwatershed #21
Watershed
N Load (no
BMP)
lb/year
W1
W2
W3
W4
W5
Total
lb/year
412.0
104.9
2.4
100.0
411.2
1030.4
Subwatershed #27
Watershed
N Load (no
BMP)
lb/year
W1
W2
W3
W4
W5
Total
lb/year
P Load (no
BMP)
lb/year
lb/year
837.5
213.8
4.8
205.2
1165.0
2426.3
BOD Load (no
BMP)
lb/year
17.9
340.5
2.8
513.5
355.2
1229.9
P Load (no
BMP)
lb/year
314.5
1202.8
5.7
1349.5
1027.1
3899.6
BOD Load (no
BMP)
129.7
31.7
0.7
27.2
126.6
315.8
52.8
1215.3
8.7
2095.8
1321.7
4694.3
Subwatershed #28
Watershed
N Load (no
BMP)
W1
W2
W3
W4
W5
Total
P Load (no
BMP)
106.8
2489.6
17.7
4327.5
4302.1
11243.7
BOD Load (no
BMP)
lb/year
103.2
358.4
1.8
359.8
279.8
1103.0
637.2
2454.2
11.6
2773.1
3302.4
9178.5
100 acres
Sediment
Load (no
BMP)
t/year
88.9
20.8
0.5
15.7
93.5
219.4
482 acres
Sediment
Load (no
BMP)
t/year
13.1
204.5
1.9
251.3
243.8
714.6
363 acres
Sediment
Load (no
BMP)
t/year
73.7
231.8
1.3
201.8
193.6
702.3
N Load
Reduction
initial load
new load
load reduc
619.2
411.2
208.1
N Load
Reduction
initial load
new load
load reduc
3372.6
1321.7
2050.9
N Load
Reduction
initial load
new load
load reduc
Totals
2872.5
1027.1
1845.4
N
13285.0
P Load
Reduction
189.2
126.6
62.7
P Load
Reduction
874.6
355.2
519.4
P Load
Reduction
823.2
279.8
543.4
P
3755.8
Sediment
Load
Reduction
125.8
93.5
32.3
Sediment
Load
Reduction
470.8
243.8
227.0
Sediment
Load
Reduction
508.7
193.6
315.1
Sediment
1927.0
Explanation of Methodology:
All pollutant load reduction calculations were developed utilizing EPA's Spreadsheet Tool for Estimating Pollutant Load (STEPL) with the help of
MDEQ staff. Only subwatershed's characterized as "highly critical" were included in the analysis. A separate analysis was conducted for each
subwatershed. The input date for each subwatershed was a summary of the hydrologic soil groups present by acreages. A step by step process
follows:
1. Launch the STEPL model and select the number of subwatersheds equal to the number of hydrologic groups per subwatershed plus one (the
additional subwatershed will be used to calculated loads associated with wetlands).
2. Click the yes button to show additional input tables.
3. Input the number of acres for each hydrologic group in box 1 under cropland, and then put total acres under "user defined".
4. Go to box 5 and select the hydrologic groups as appropriate for each subwatershed. Because the "user defined" class will represent wetland, select
D hydrologic soil group.
5. In box 6 input 78 in the user defined under D soils
6. In box 7 under user defined inpu 0.79 for N, 0.08 for P and a 4 for BOD.
Here is some information for the methodology section for load reduction calculation for wetland restoration:
All presettlement wetlands within the thirteen critical subwatersheds that were identified in Landscape Level Functional Wetlands Assessment as
performing "high" for sediment and other particles retention and nutrient transformation were selected for load reduction estimates. These high
performing wetlands were then intersected in a GIS with agricultural lands and load reductions are estimated for these areas.
The Natural Resource Conservation Service’s Soil Survey Geographic (SSURGO) Database and Soil Data Viewer were used to determine the current
hydrologic groups of the potential wetland restoration areas and the acreage of each hydrologic group was summed by critical subwatersheds.
Wetlands event mean concentrations for nutrients were obtained from the Rouge Program Office Technical Memorandum RPO-MOD-TM34.00 and
are as follows:
Total phosphorus concentration = 0.08 mg/L
Total Kjeldahl Nitrogen concentration = 0.79 mg/L
The NRCS’s curve number of 78 was used for wetland. The Grand Rapids, Michigan WSFO weather station was used.
APPENDIX O: Summary of Estimated Pollutant Load Reductions for Traditional Agricultural BMPs
SUB
1
2
3
4
5
6
7
10
11
12
14
15
16
18
19
20
21
22
23
24
26
27
28
29
30
31
37
38
41
42
45
NAME
BEAVER DAM TO MR
MR TO BEAVER DAM
MR@72ND
MR@I-196
MR TO HUNDEMAN
BIG TO HUNDERMAN
HUNDEMAN TO BIG
UNNAMED TO PETERS 10
PETERS
UNNAMED TO PETERS 12
KLEINHEKSEL
JAARDA TO SB
SBMR TO JAARDA
EAST FILLMORE
SBMR TO MR
NBMR TO DEN BLEYKER 20
VANDERBIE/ROTMAN
NBMR TO DEN BLEYKER 22
DEN BLYKER
NBMR @M-40
BOSH&HULST @104TH
BOSCH&HULST TO NOORD
TRIB TO BOSCH&HULST
HUNTERS TO BROWER
BROWER TO HUNTERS
NOORDELOOS TO #52
NORTH HOLLAND TO #40
#15&17 TO #40
MAPLEWOOD TO MR
TROOST&BOVEN TO PINE
#37 TO PINE
Totals
Totals (High Priority)
Totals (Mod Priority)
SEDIMENT
REDUCTION
(TONS/YR)
P REDUCTION
(LBS/YR)
N REDUCTION
(LBS/YR)
1236
70
1809
170
4419
346
3533
4648
9083
2015
1913
1786
1617
2668
4871
5048
1690
1113
3725
2922
2242
605
333
1003
583
670
1672
1079
1415
1272
1173
692
1092
62
639
169
48909
24111
24798
2810
2669
2488
2301
3727
5708
5999
2393
1577
4567
4081
3175
856
465
1401
814
933
2437
1572
2071
1861
1717
962
1598
87
1051
236
66184
32014
34170
5631
5347
4985
4621
7468
11424
13002
4796
3159
10057
8178
6362
1716
932
2808
1632
1866
4875
3144
5059
4546
4195
1925
3899
174
1787
471
137909
65802
72107
Moderately Critical Agricultural Areas
Highly Critical Agricultural Areas
FOR COMPLETE DESCRIPTION OF METHODOLOGY SEE APPENDIX R
APPENDIX O: Estimated Pollutant Load Reductions for Traditional Agricultural BMPs
(Recommendations made by Allegan Conservation District)
FILTER STRIPS
SUB
1
2
3
4
5
6
7
10
11
12
14
15
16
18
19
20
21
22
23
24
26
27
28
29
30
31
37
38
41
42
45
NAME
BEAVER DAM TO MR
MR TO BEAVER DAM
MR@72ND
MR@I-196
MR TO HUNDEMAN
BIG TO HUNDERMAN
HUNDEMAN TO BIG
UNNAMED TO PETERS 10
PETERS
UNNAMED TO PETERS 12
KLEINHEKSEL
JAARDA TO SB
SBMR TO JAARDA
EAST FILLMORE
SBMR TO MR
NBMR TO DEN BLEYKER 20
VANDERBIE/ROTMAN
NBMR TO DEN BLEYKER 22
DEN BLYKER
NBMR @M-40
BOSH&HULST @104TH
BOSCH&HULST TO NOORD
TRIB TO BOSCH&HULST
HUNTERS TO BROWER
BROWER TO HUNTERS
NOORDELOOS TO #52
NORTH HOLLAND TO #40
#15&17 TO #40
MAPLEWOOD TO MR
TROOST&BOVEN TO PINE
#37 TO PINE
Totals
Totals (High Priority)
Totals (Mod Priority)
SEDIMENT
REDUCTION
(TONS/YR)
P REDUCTION
(LBS/YR)
NOTILL
N REDUCTION
(LBS/YR)
SEDIMENT
REDUCTION
(TONS/YR)
P REDUCTION
(LBS/YR)
OTHER PRACTICES
N REDUCTION
(LBS/YR)
5
3
30
7
4
46
15
8
93
1231
67
1802
166
4405
338
2324
3468
6936
1
4
8
14
9
33
43
3
4
15
4
18
3
0
3
4
1
3
5
6
5
5
1
12
4
1
2
249
177
71
2
6
11
19
13
40
59
5
5
21
6
26
4
1
5
6
2
4
8
9
8
7
1
18
6
3
3
356
249
107
4
12
23
39
26
87
119
9
11
41
13
53
7
1
10
12
3
9
16
19
15
15
2
36
13
5
5
719
505
214
2013
1909
1778
1603
2659
4212
3581
1687
1110
3206
2917
2224
602
332
1000
579
669
1669
1073
1409
1267
1168
691
1080
58
638
167
44925
25071
19855
2808
2663
2477
2282
3714
5042
4515
2389
1571
4042
4075
3149
852
464
1397
809
932
2433
1564
2061
1853
1710
961
1580
80
1049
233
62140
33784
28356
5627
5335
4963
4582
7442
10082
10034
4787
3149
9006
8165
6310
1708
931
2798
1620
1863
4866
3129
5040
4531
4180
1923
3863
161
1782
466
130021
69552
60469
Moderately Critical Agricultural Areas
Highly Critical Agricultural Areas
SEDIMENT
REDUCTION
(TONS/YR)
P REDUCTION
(LBS/YR)
TOTALS
N REDUCTION
(LBS/YR)
1180
1134
2055
626
1424
626
1424
1255
2850
504
504
1010
3735
3735
0
3688
3688
0
7169
7169
0
FOR COMPLETE DESCRIPTION OF METHODOLOGY SEE APPENDIX R
SEDIMENT
REDUCTION
(TONS/YR)
1236
70
3533
0
2015
1913
1786
1617
2668
4871
5048
1690
1113
3725
2922
2242
605
333
1003
583
670
1672
1079
1415
1272
1173
692
1092
62
639
169
48909
28983
19926
P REDUCTION
(LBS/YR)
1809
170
4648
0
2810
2669
2488
2301
3727
5708
5999
2393
1577
4567
4081
3175
856
465
1401
814
933
2437
1572
2071
1861
1717
962
1598
87
1051
236
66184
37721
28463
N REDUCTION
(LBS/YR)
4419
346
9083
0
5631
5347
4985
4621
7468
11424
13002
4796
3159
10057
8178
6362
1716
932
2808
1632
1866
4875
3144
5059
4546
4195
1925
3899
174
1787
471
137909
77226
60683
APPENDIX O: Details for Estimated Pollutant Load Reductions for Traditional Agricultural BMPs
SUB
1
2
3
4
5
6
7
10
11
12
14
15
16
18
19
20
21
22
23
24
26
27
28
29
30
31
37
38
41
42
45
NAME
POOR STREAM (FT)
BEAVER DAM TO MR
MR TO BEAVER DAM
MR@72ND
MR@I-196
MR TO HUNDEMAN
BIG TO HUNDERMAN
HUNDEMAN TO BIG
UNNAMED TO PETERS 10
PETERS
UNNAMED TO PETERS 12
KLEINHEKSEL
JAARDA TO SB
SBMR TO JAARDA
EAST FILLMORE
SBMR TO MR
NBMR TO DEN BLEYKER 20
VANDERBIE/ROTMAN
NBMR TO DEN BLEYKER 22
DEN BLYKER
NBMR @M-40
BOSH&HULST @104TH
BOSCH&HULST TO NOORD
TRIB TO BOSCH&HULST
HUNTERS TO BROWER
BROWER TO HUNTERS
NOORDELOOS TO #52
NORTH HOLLAND TO #40
#15&17 TO #40
MAPLEWOOD TO MR
TROOST&BOVEN TO PINE
#37 TO PINE
Totals
Totals (High Priority)
Total (Mod Priority)
Moderately Critical Agricultural Areas
Highly Critical Agricultural Areas
BUFFER (AC)
RESIDUE MGT (AC)
9155
5586
4
3
1233
1074
60045
28
2668
2092
6024
11493
17345
14345
30826
51684
5028
5854
18855
7158
29205
4154
781
5352
6442
3753
5442
9650
11564
9522
9246
2996
22632
14466
3747
6565
391006
218754
172251
1
3
5
8
7
14
24
2
3
9
3
13
2
0
2
3
2
2
4
5
4
4
1
10
7
2
3
180
100
79
1564
1554
1455
1451
2109
1601
1818
1505
945
1673
2350
1922
497
264
769
452
1156
1705
1114
1433
1269
1188
1193
1132
107
1111
280
38591
16752
21839
COVER CROP (AC)
320
CRITICAL AREA
PASTURE (AC)
106
GRASSED WATERWAY
(AC)
5
7
19
6
320
106
FOR COMPLETE DESCRIPTION OF METHODOLOGY SEE APPENDIX R
37
Management Measure: Drainage water management system applied to 50% of the drained land in
highly critical agricultural subwatersheds
1. Total load by subwatershed(s)
Subwatershed
Total
Agricultural
Acres
W3
W4
W7
W10
W14
W15
W16
W18
W20
W21
W27
W28
Total
1067.5
1753.5
1576.1
2057.1
2617.2
2114
1122.5
2220.2
2168.4
482.5
2268.2
1482.7
20929.9
Estimated
N Load (no P Load (no
BOD Load (no
Acres of
BMP)
BMP)
Drained Land BMP)
lb/year
lb/year
lb/year
427
2562.9
615.5
5297.9
701.4
4071.1
957.6
8424.9
630.44
3685.4
870.8
7624.7
1028.55
5822.1
1347.3
12058.6
1701.18
9326.5
2111.8
19338.5
1374.1
7635.1
1744.9
15824.0
729.625
4223.9
991.9
8741.8
1443.13
7993.9
1823.0
16569.3
867.36
4964.4
1157.2
10278.3
193
1390.8
367.7
2859.3
907.28
5177.6
1204.6
10720.9
593.08
3481.2
824.7
7201.4
10596.145
60334.8
14017.1
124939.3
Sediment
Load (no
BMP)
t/year
290.1
433.2
397.5
589.0
879.5
742.2
447.1
771.7
513.8
203.7
532.7
378.4
6179.0
Drainage Water Management (30% reduction)
Applied to 50% of drained land (5298 acres)
Estimated Pollutant Reduction
9050
2103
18741
N
P
BOD
Negligible
Sediment
Management Measure:Gypsum amendments applied to 50% of the agricultural land in
highly critical agricultural subwatersheds
Total load by subwatershed(s) as calculated by EPA's STEPL Model
Sediment
N
Load
(no
P
Load
(no
BOD
Load
Load (no
SubAgricultural
BMP)
BMP)
(no BMP) BMP)
watershed
Acres
lb/year
lb/year
lb/year
t/year
W3
1067.5
6028.0
1392.8
12486.2
606.8
W4
1753.5
9595.2
2169.7
19897.0
900.9
W7
1576.1
6910.4
1692.7
14269.4
827.8
W10
2057.1
8833.4
2137.7
18252.3
1022.3
W14
2617.2
11031.8
2640.1
22808.5
1236.0
W15
2114
9058.5
2189.4
18718.8
1044.5
W16
1122.5
5056.3
1257.4
10432.1
631.6
W18
2220.2
9477.6
2285.5
19587.1
1085.8
W20
2168.4
9273.4
2238.7
19163.9
1065.7
W21
482.5
2329.5
600.6
4796.4
320.3
W27
2268.2
9666.5
2328.8
19978.6
1104.2
W28
1482.7
6532.3
1604.5
13486.7
788.5
Total
20929.9
93793.1
22537.8
193877.1
10634.4
Gypsum Amendments (30% reduction of phosphorus, sediment and runoff)
No data was confirmed to estimate reduction of nitrogen
Applied to 50% of agricultural land (10,465 acres)
Estimated Pollutant Reduction
Unknown
3381
29082
1595
N
P
BOD
Sediment
Management Measure:Two-stage ditch design applied in any subbasins with highly critical
ag subwatersheds
Subbasins
(with highly critical
subwatersheds)
Upper Macatawa
Peters Creek
South Branch
North Branch
Noordeloos Creek
Totals
Streambank Erosion1
N
P
S
lbs/yr
lbs/yr
tons/yr
870
435
435
754
377
377
2484
1242
1242
2470
1235
1235
1902
951
951
8480
4240
4240
2
Surface Runoff Erosion
N
P
S
lbs/yr
lbs/yr
tons/yr
44885
8196
1343
18359
3440
640
33271
6109
1092
35774
6533
1118
48067
8245
1223
180356
32523
5416
1: 2011 Geomorphology Report
2: 2009 MDEQ Pollutant Loading Report
Two-Stage Ditch (25% reduction of phosphorus, 23% reduction nitrogen and 15% reduction in sediment)
Estimated Pollutant Reduction
43432
9191
1448
N
P
Sediment