Practices for Improving Range and Pasture Runoff WQ

annual rangeannual range

irrigated pastureirrigated pasture

Survey of 10 stream diversion based irrigated meadows

1. Diversion

3. Return

2. Flood-irrigated pasture

Irrigatedpasture

Irrigatedpasture 52 cfu/100 mL

1,116 cfu/100 mL1,303 cfu/100 mL

Ranch A

Ranch B

Sample above and below, record managementSample above and below, record management

2.81.41.00.0-1.94.5-5.52.2-2.0-2.3TSS

2.31064108.423098.28880.12170.2126

54.01152.7104

24.6-1823-0.1-233222.0-10361E.C.E. coliStream

Change in Concentration (Below – Above)

Irrigation Application Rate & Runoff Rate

0

20

40

60

80

100

0.000 0.005 0.010 0.015 0.020 0.025

Irrigation Application Rate (cfs/ac)

E. c

oli (

cfu/

100m

L)

upstream downstream

Runoff - decrease.

Cattle Stocking Density (AU = 1 cow)

0

300

600

900

1,200

1,500

1,800

0 1 2 3 4 5 6

Animal Units/ha

E. c

oli (

cfu/

100m

L)

Upstream Downstream

Reduce high stock densities.Move cattle before irrigation.

0.0 0.8 1.2 1.6 2.0 2.40.4

Animal Unit per Acre

Foothill and valley flood irrigated pastures

• Studies at SFREC from small plot to pasture scale.

• Rotational grazing – disconnect active grazing from

irrigation events.

• Irrigation application – minimize tailwater generation.

E. coli increases with tailwater runoff rate

Tail Water Runoff Rate (cfs/acre)

0.00 0.25 0.50 0.75 1.00 1.25 1.50

E. c

oli (

cfu/

100m

l)

3000

3500

4000

4500

5000

5500

Decrease runoff.

0

1,000

2,000

3,000

4,000

5,000

0 10 20 30

Days Since Grazed

E. c

oli

(cfu

/100

mL)

Above Wetland

Below Wetland

E. coli reduced by rest from grazing before irrigation

Increase rest from grazing before irrigation.

E. coli decay in fecal pat at SFREC Aug 2008

0

400

800

1200

1600

0 1 2 3 4 5 6 7 8Fecal Pat Age (Day)

E. c

oli

Con

cent

ratio

n (x

1,00

0,00

0)

Plus crusting to reduce erosion of the pat and release of microbes

Fecal pat and air temprature at SFREC Oct. 13-14, 1999

50

70

90

110

130

12:00 AM 12:00 PM 12:00 AM 12:00 PM 12:00 AM

Tem

pera

ture

(F)

Fecal Pat (Sun) Air

All dead in 1 day

Air > 78 F

Fecal > 104 F

Significant thermal inactivation of C. parvum during spring, summer, fall.

Effect of land slope and fecal pat age on generic E. coli flux from annual rangeland under natrual rainfall-runoff conditions with a 1.0 m buffer, 1 since last storm, 100 mm rain.

0

200

400

600

800

1000

1200

1400

0 6 12 18 24

Fecal Pat Age (day)

E. c

oli

Flux

(cfu

X10

00)

5%

20%

35%Rainfall

Annual Range - Winter

pat

Rainfall

Location, location, location>90% of E. coli, C. parvum, Giardia, Salmonella load

retained in the fecal pat or trapped within 1 ft

pat

Rainfall

Location, location, locationAn additional 30% to 99.9% trapped within 1 yard of pat

pat

>90% trapped at fecal pat

30-99% trapped every 1 yard of travel distance

Distribute cow pats away from streams and the whole range is a buffer

Keep it out of the creek

0

40

80

120

160

200

0-10% 11-20% 21-30% >30% VSA LCAWatershed Position

Feca

l Loa

d kg

/ha

Wet Season Dry Season

Fecal loading rates are dependent upon season, watershed position, & management. Supplement

Shade

Water

• Move existing supplement and

water sites out of near-stream

locations.

• Evaluate trails leading to and

from existing and proposed

sites – do they link site to

surface water?

Do you know where is your supplement is?

Stream

Stream

Supplement

Appropriate grazing pressure to maintain soil surface infiltration rates and natural buffering capacity.

L M H

RDM – residual dry matter (lb/ac)

E. coli flux decreased from 200 to 1,000 lb/ac forage cover, but increased from 1,000 to 4,000

200 lbs/ac 1,000 lbs/ac 4,000 lbs/ac

RDM Level

infiltration - filtration

environmental growth - survival

Irrigated Pasture

• Reduce runoff rates

• Moderate stocking rates

• Remove cattle before irrigation – allow

mortality/crusting

• Avoid direct in-stream fecal/urine deposition

Annual Range

• Moderate stocking rates

• Use livestock attractants to distribute livestock away from streams

• Avoid direct in-stream feces and urine deposition

• Timing of pasture use – allow mortality/crusting