Vegetative filter strips for controlling feedlot runoff .... atikur_NDWRRI_presentation.pdf · Vegetative filter strips for controlling feedlot runoff pollution in North Dakota ...

Vegetative filter strips for controlling feedlot runoff pollution in North Dakota

Atikur Rahman PhD Candidate

Ag. and Biosystems Engineering, NDSU 7 February, 2013

WRRI Fellowship Research Presentations NDWQMC Meeting, Fargo

Outline

• Introduction

• Materials and Methods

• Results and Discussion

• Conclusions

Introduction • One of the major sources of water pollution is

agricultural production practices

• Water pollution due to eutrophication caused by the excessive P in the water bodies

• Animal industry accounts for 16% water impairment from agricultural production (USEPA, 2001)

In North Dakota • Almost 90% of the state’s land is occupied by

farms and ranches • Cattle 1.7 m, Pigs 1.6 m, and Sheep 0.88 m heads • As published by NDDoH, 2012, nutrients loading

from • erosion & runoff from cropland, • hydrologic modification and • runoff from animal feeding operations

Introduction (Contd.)

• Significant portion of the state’s surface water is

either threatened or does not support the aquatic life use due to excessive nutrient loadings

• BMPs must be developed to prevent water quality degradation

Introduction (Contd.)

• Containment structures are commonly used • Disadvantages are:

– expensive – occupies large area – requires regular maintenance, and – risks groundwater pollution Alternative practice is needed

Introduction (Contd.)

• Vegetative filter strips (VFS) is an alternative to containment structure

• Depending on the geographical region, VFS design criteria varied significantly

• VFS performance needs to be evaluated based on local and regional climatic condition and design criteria

Vegetative Filter Strips (VFS)

Objectives

• To evaluate the performance of vegetative filter strips installed at the down-slope end of feedlots under North Dakota climatic and management practices

Study Area

Figure 1: Locations of the study area

Sampling points

Fig. Layout of a VFS system and sample collection

Layout of VFS system

Layout of VFS system

FeedlotBuffer strip

Settling basin

FeedlotGrass area

Retaining pond

Solids separator

Buffer strip

Sampling points

At Richland County At Cass County

Actual VFS

Instrumentation • Inflow (before entering into buffer) and outflow (after leaving buffer) • With bucket and float arrangement

• ISCO 6712

Runoff samples - Nutrients

- Total phosphorus (TP) and ortho-phosphorus (OP) - Total Kjeldahl nitrogen (TKN), nitrate-nitrogen (NO3-

N), and ammonium nitrogen (NH4-N) - Potassium (K)

- Solids - Total solids (TS) - Total suspended solids (TSS)

- pH - Electrical conductivity (EC)

Sample Analysis

• Paired ‘t’ test performed to compare mean pollutant concentrations between inflow and out flow of VFS

• The null hypothesis tested was that mean pollutant concentrations between inflow and out flow of VFS were same

• All statistical analyses were performed in the SAS 9.2

Statistical Analysis

TSS concentration trend- Cass County

0

20

40

60

80

100

120

140

1600

500

1000

1500

2000

2500

3000

350025

-Jul

1-Au

g

2-Au

g

12-A

ug

10-O

ct

18-A

pr

23-A

pr

23-M

ay

29-M

ay

11-Ju

n

13-Ju

n

20-Ju

n

25-Ju

l

8-Au

g

2011 2012

Rain

fall,

mm

TSS

conc

entr

atio

n, m

g/L

Sampling dates

Inflow Outflow Rainfall

0

20

40

60

80

100

1200

500

1000

1500

2000

2500

14-Jul 2-Aug 15-Aug 29-May 14-Jun 20-Jun 26-Jul

2011 2012

Rain

fall,

mm

TSS

conc

entr

atio

n, m

g/L

Sampling dates

Inflow Outflow Rainfall

TSS concentration trend- Sargent County

0

20

40

60

80

100

120

1400

500

1000

1500

2000

2500

3000

3500

4000

4500

Rain

fall,

mm

Tota

l sus

pend

ed s

olid

s, m

g/L

Sampling date

Inflow Outflow Rainfall

TSS conc. trend- Richland County

0

20

40

60

80

100

120

140

1600

50

100

150

200

25025

-Jul

1-Au

g

2-Au

g

12-A

ug

10-O

ct

18-A

pr

23-A

pr

23-M

ay

29-M

ay

11-Ju

n

13-Ju

n

20-Ju

n

25-Ju

l

8-Au

g

2011 2012

Rain

fall,

mm

TP c

once

ntra

tion,

mg/

L

Sampling dates

Inflow Outflow Rainfall

TP concentration trend- Cass County

0

20

40

60

80

100

120

1400

20

40

60

80

100

120

140

160

180

14-Jul 2-Aug 15-Aug 29-May 14-Jun 20-Jun 26-Jul

2011 2012

Rain

fall,

mm

TP c

once

ntra

tion,

mg/

L

Sampling dates

Inflow Outflow Rainfall

TP concentration trend- Sargent County

0

20

40

60

80

100

1200

10

20

30

40

50

60

Rain

fall,

mm

TP c

once

ntra

tion,

mg/

L

Sampling date

Inflow Outflow Rainfall

TP conc. trend- Richland County

0

20

40

60

80

100

120

140

1600

50

100

150

200

250

30025

-Jul

1-Au

g

2-Au

g

12-A

ug

10-O

ct

18-A

pr

23-A

pr

23-M

ay

29-M

ay

11-Ju

n

13-Ju

n

20-Ju

n

25-Ju

l

8-Au

g

2011 2012

Rain

fall,

mm

TKN

/TN

con

cent

ratio

n, m

g/L

Sampling dates

Inflow Outflow Rainfall

TKN/TN conc. trend- Cass County

0

20

40

60

80

100

1200

20

40

60

80

100

120

140

160

180

200

14-Jul 2-Aug 15-Aug 29-May 14-Jun 20-Jun 26-Jul

2011 2012

Rain

fall,

mm

TKN

/TN

con

cent

ratio

n, m

g/L

Sampling dates

Inflow Outflow Rainfall

TKN/TN concentration trend- Sargent County

At Richland County

0

20

40

60

80

100

1200

50

100

150

200

250

300

Rain

fall,

mm

TKN

con

cent

ratio

n, m

g/L

Sampling date

Inflow Outflow Rainfall

TKN conc. trend- Richland County

VFS Performance at Cass County

-700

-600

-500

-400

-300

-200

-100

0

100

200

EC TS TSS Ortho-P TP NH4-N NO3-N TKN/TN K

%Re

duct

ion

of c

once

ntra

tion

Pollutants

2011 2012

VFS Performance at Sargent County

-150

-100

-50

0

50

100

EC TS TSS Ortho-P TP NH4-N NO3-N TKN/TN K

%Re

duct

ion

of c

once

ntra

Pollutants

2011 2012

VFS Performance at Richland County

0

10

20

30

40

50

60

70

80

TS TSS Ortho-P TP NH4-N TKN/TN K

%Re

duct

ion

of c

once

ntra

tion

Pollutant

2010

Overall • Vegetative filter strip was effective for sediment

and sediment bound pollutant reduction

• Soluble pollutants were not effectively removed

• Cass County feedlot with longer flow length (65 m), dense broadleaf cattail grass filter bed outperformed the Sargent and Richland Counties

Acknowledgements • NDDoH (EPA 319 grants) • ND-WRRI • Sargent County Feedlot • Richland County Feedlot • Cass County Feedlot

Thank you

Questions?

Feedlot Description Features Parameters Cass County (CC)

feedlots Sargent County (SC) feedlots Richland County

(RC) feedlots Climate Annual average

rainfall, mm 494 494 468

Feedlot

Length, m 50 76 Width, m 115 62

Soil texture Clay Fine sandy loam Sandy loam

Number of pens 6 8 2 Designed animal

capacity 200 180 - 200 250

VFS

Flow-length, m 65 40 12 Soil texture Clay Fine sandy loam Sandy loam

Vegetation type Common cattails garrison creeping foxtail and reed canarygrass

Mixed

Slope, % 2 3 2

Runoff

Runoff distribution Direct overland flow Channelized flow with a solids separator

Direct overland flow