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
Recommended
