This document summarizes a study on the impacts of on-farm water storage systems on water quality and quantity in the Porter Bayou watershed in Mississippi. Key findings include: 1. Nutrient concentrations were generally higher in fall, winter, and spring and lower in summer. Nitrate levels decreased by 32-67% through the storage systems. 2. Total phosphorus decreased by 22% in fall at one farm. 3. The storage systems saved substantial water - over 80 million gallons at one farm and 153 million gallons at another. 4. Outreach activities involved modeling watershed effects, collaboration with research partners, and education programs.

1. Joel O. Paz, Mary Love M. Tagert, Jonathan W. Pote,
and Charles L. Wax
USDA NIFA
Project Directors Meeting
Greensboro, NC
July 27-28, 2015
Downstream Water Quality and Quantity
Impacts of Water Storage Systems in
Porter Bayou Watershed
Grant Agreement Number: 2011-51130-31168

2. Introduction
 Since the 1970’s,
groundwater levels in
the MS Alluvial Aquifer
have decreased
(100,000 to 300,000
acre-feet/year) due to an
increase in irrigated
acres (YMD Water
Management Plan, 2006;
USDA-NRCS, 1998).
 Increasing hypoxic zone
(Rabalais and Turner, 2010).
Sunflower
County

3. Motivation
 Two main impediments to sustainability of
agroecosystems in the MS Delta:
1. Declining groundwater levels in the MS Delta
Alluvial Aquifer
2. Nutrient loads to the MS River and the Gulf of
Mexico
 Goal: Determine the impacts of water storage
systems on water quality and quantity

4. Study Area
 Porter Bayou drains into
Big Sunflower River
 EPA Priority Watershed
(HUC 08030207)
 MRBI focus area watershed
 2008 TMDL report indicated
reduction of nutrients
could be accomplished
with the installation of
BMPs (MDEQ)

5. Main Objectives
1. Determine the downstream nitrogen and
phosphorus concentrations of effluent from water
storage systems.
2. Quantify the effects of water storage systems on
downstream flow levels through a watershed.
3. Increase the adoption of on-farm water storage
technology and dissemination of potential
benefits.
4. Enhance the science education of middle and high
school students by promoting the benefits of water
conservation and environmental stewardship.

6. Tailwater Recovery Ditch
Storage Pond
On-Farm Storage Water System

7. Original:
Center Pivot System
Construction of
Tailwater Recovery Ditch

8. Precision land forming, pads and pipes

9. After Precision Land Forming and
Construction of OFWS
• Switched from center pivot to furrow irrigation with poly-pipe
• Capturing all runoff from rainfall and irrigation tailwater

10. On-Farm Water Storage System
 Ratio of 16 acres irrigated area : 1 acre
reservoir
 Reservoir depth is 8 feet
 TWR ditch at 0.3 ac-ft. per acre, with minimum
10 ac-ft. of storage on any system
 4 ft. berm and minimum 6” overflow pipe
Metcalf Farm

11. Pitts Farm
On-Farm Water Storage System

12. On-Farm Water Storage System

13. Study Area
90°30'W90°35'W90°40'W90°45'W90°50'W
33°50'N
33°45'N
33°40'N
33°35'N
33°30'N
33°25'N
Elevation (m)
High : 150
Low : 90
#0
#0
#0
#0
#0
#0
#0
#0
#0
Study area's boundary
Tail-water recovery ditch
Pond
#0 Sampling station
0 0.1 Miles
0 0.1 Kilometers
0 2 4 Kilometers
0 2 4 Miles
0 0.1 Miles
0 0.1 Kilometers
M3
MP
M2
M1
P1
P4
P2
PP
P3
Pitts Farm
Metcalf Farm

14. Methods: Grab samples
 Samples were collected
from inlet(s), TWR canal,
outlet, and storage pond
on both farms.
 Samples were collected
every three weeks during
growing season, and every
six weeks during winter.
 Samples were analyzed
for pH, electrical
conductivity, dissolved
oxygen, nitrogen and
phosphorus species, and
suspended solids.

15. Methods: Automated stormwater samples
 Samples were collected at
mid-point of recovery
channel.
 Samples were collected
using ISCO automatic
samplers set to sample
based on a rise in channel
water level.
 Samples were analyzed for
the same nutrient species
as grab samples.

16. Highlights
 Overall pattern for the
median NO3-N and total
phosphorus concentration:
Higher values – fall, winter,
and spring
Lower values – summer
 Compared to the TWR ditch
(sampling site P2), the median
NO3-N concentration at the
outlet (P3) was reduced 67%
during the winter, 50% during
spring, and 32% during fall.
P1
P2
P3
P4
PP

17. Seasonal Variability of NO3-N Concentration
Pitts Farm
S1-Winter; S2-Spring; S3-Summer; S4-Fall

18. Summary of hypothesis test results for detecting
statistically significant changes in NO3-N concentration
Sampling Station
Season S1 S2 S3 S4 S1 S2 S3 S4 S1 S2 S3 S4 S1 S2 S3 S4
S1 0.86 - - - 0.36 - - - 0.19 - - - 1 - - -
S2 - 0.44 - - - 0.19 - - - 0.1 - - - 0.99 - -
S3 - - 0.06 - - - 0.76 - - - 0.57 - - - 1 -
S4 - - - 0.96 - - - 1 - - - 0.004 - - - 0.37
S1 - - - - 0.1 - - - 0.98 - - - 1 - - -
S2 - - - - - 0.1 - - - 0.99 - - - 0.99 - -
S3 - - - - - - 1 - - - 0.05 - - - 1 -
S4 - - - - - - - 0.1 - - - 0.71 - - - 0.98
S1 - - - - 0.78 - - - 1 - - -
S2 - - - - - 0.98 - - - 1 - -
S3 - - - - - - 0.36 - - - 1 -
S4 - - - - - - - 0.25 - - - 0.98
S1 - - - - 1 - - -
S2 - - - - - 0.99 - -
S3 - - - - - - 1 -
S4 - - - - - - - 0.99
P1
P2
P3
P4
P2* P3* P4** PP***
(* right-tailed, ** two-tailed, and *** left-tailed p-values;
bold-faced values indicate evidence against the null hypothesis)

19. Seasonal Variability of Total Phosphorus Concentration
Pitts Farm
S1-Winter; S2-Spring; S3-Summer; S4-Fall

20. Summary of hypothesis test results for detecting
statistically significant changes in TP concentration
(* right-tailed, ** two-tailed, and *** left-tailed p-values;
bold-faced values indicate evidence against the null hypothesis)
Sampling Station
Season S1 S2 S3 S4 S1 S2 S3 S4 S1 S2 S3 S4 S1 S2 S3 S4
S1 0.39 - - - 0.5 - - - 0.55 - - - 0.98 - - -
S2 - 0.23 - - - 0.23 - - - 0.65 - - - 0.98 - -
S3 - - 0.19 - - - 0.27 - - - 0.52 - - - 0.99 -
S4 - - - 0.63 - - - 0.58 - - - 0.45 - - - 0.980
S1 - - - - 0.5 - - - 0.2 - - - 1 - - -
S2 - - - - - 0.64 - - - 0.27 - - - 0.98 - -
S3 - - - - - - 0.7 - - - 0.07 - - - 0.98 -
S4 - - - - - - - 0.35 - - - 0.48 - - - 0.99
S1 - - - - 0.45 - - - 0.98 - - -
S2 - - - - - 0.3 - - - 0.98 - -
S3 - - - - - - 0.22 - - - 0.98 -
S4 - - - - - - - 0.18 - - - 0.99
S1 - - - - 1 - - -
S2 - - - - - 0.99 - -
S3 - - - - - - 0.99 -
S4 - - - - - - - 0.99
P4**
P1
PP***
P2
P3
P4
P2* P3*

21. Seasonal Variability of NO3-N Concentration
Metcalf Farm
S1-Winter; S2-Spring; S3-Summer; S4-Fall

22. Summary of hypothesis test results for detecting
statistically significant changes in NO3-N concentration
(* right-tailed, ** two-tailed, and *** left-tailed p-values;
bold-faced values indicate evidence against the null hypothesis)
Sampling Station
Season S1 S2 S3 S4 S1 S2 S3 S4 S1 S2 S3 S4
S1 0.99 - - - 0.99 - - - 0.33 - - -
S2 - 0.99 - - - 0.99 - - - 0.05 - -
S3 - - 0.1 - - - 0.21 - - - 0.99 -
S4 - - - 0.9 - - - 0.99 - - - 0.08
S1 - - - - 0.17 - - - 0.99 - - -
S2 - - - - - 0.007 - - - 0.99 - -
S3 - - - - - - 0.99 - - - 0.99 -
S4 - - - - - - - 0.7 - - - 0.17
S1 - - - - 0.38 - - -
S2 - - - - - 0.22 - -
S3 - - - - - - 0.99 -
S4 - - - - - - - 0.24
M1
M2
M3
M2* M3* MP**

23. Seasonal Variability of Total Phosphorus Concentration
Metcalf Farm
S1-Winter; S2-Spring; S3-Summer; S4-Fall

24. Summary of hypothesis test results for detecting
statistically significant changes in
Total Phosphorus concentration
(* right-tailed, ** two-tailed, and *** left-tailed p-values;
bold-faced values indicate evidence against the null hypothesis)
Sampling Station
Season S1 S2 S3 S4 S1 S2 S3 S4 S1 S2 S3 S4
S1 0.99 - - - 0.77 - - - 0.13 - - -
S2 - 0.98 - - - 0.91 - - - 0.81 - -
S3 - - 0.42 - - - 0.44 - - - 0.99 -
S4 - - - 0.78 - - - 0.94 - - - 0.09
S1 - - - - 0.03 - - - 0.97 - - -
S2 - - - - - 0.1 - - - 0.99 - -
S3 - - - - - - 0.7 - - - 0.99 -
S4 - - - - - - - 0.87 - - - 0.17
S1 - - - - 0.10 - - -
S2 - - - - - 0.99 - -
S3 - - - - - - 0.99 -
S4 - - - - - - - 0.3
M3
M3* MP**
M1
M2
M2*

25. Volume of Water Pumped from
Storage Pond

26. OFWS – Maintenance Problem
Sloughing of canal side slopes

27. Conclusions
 Overall pattern for the median NO3-N and total phosphorus
concentrations:
 Higher values – fall, winter, and spring
 Lower values – summer
 Assessment of nutrient changes through the system at Pitts
Farm showed a reduction of 67% in nitrate nitrogen
concentration during winter, 50% during spring, and 32%
during fall.
 Total phosphorus was reduced by 22% during the fall season.
 Water savings potential of OFWS systems is substantial
 Metcalf Farm : 80.6 million gallons (247.3 acre-ft)
 Pitts Farm : 153.7 million gallons (471.7 acre-ft)

28. Other Activities
 Model watershed effects of on-
farm storage systems and use
models to target placement
 Collaboration with USDA-ARS
Sed Lab in Oxford, MS
(Drs. Locke and Bingner)
 Extension and Outreach
 Education Component
 Project with MS Soybean
Promotion Board

29. Acknowledgments
 This project is funded by USDA NIFA under the National
Integrated Water Quality Program.
 Mississippi Agricultural and Forestry Experiment Station

30. Partners
 Mr. Boyer Britt and Mr. Walter Pitts
 Delta F.A.R.M.
 MS Department of Environmental Quality
 MS Wildlife Federation
 USDA-NRCS
 Yazoo MS Delta Joint Water Management District