Are water quality changes detectable2022_WRRI_D.Mir_

Are water quality changes detectable post stream
restoration?
Danielle Mir
NC DEQ, Division of Mitigation Services
WRRI, Raleigh NC. March 23 –24, 2022
Objectives
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Insight based on our current findings in relation to our objectives 1 & 3:
1. Provide case examples of water quality response to restoration.
2.Gain understanding the relative efficacy of different practices
3.Gain understanding of the time frames of improvement & their
sustainability.
4.Utilize data collected to potentially calibrate current models in use in mitigation plans.
5.Gain an understanding of the reach and watershed attributes that inform the detection of change
in water quality to help refine stated mitigation plan goals (i.e. examine a Gradient of “signal to
noise”)
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Case Study: Buckwater Site
Hillsborough, NC -Orange County
•Overall project mixture of Restoration and Enhancement
•Approximately 12,600 feet, overall drainage of 3.53 mi2
•T4 is reach subject to WQ monitoring
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Buckwater Site: Reach T4 •Project reach length 820 ft.
•Overall drainage 74 Acres
•Upper watershed 20 acres
•T4 has lower watershed noise
Downstream Site
Treatment Station
Upstream Site
Watershed Control Station
Water Quality
Monitoring Period
Pre –1.5 years
Post –2 years
Reach T4 Watershed Characteristics
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▪Watershed above upper WQ station is completely forested.
▪This is a low watershed noise case example.
▪30 ac. of the entire 74 ac. watershed had stressors.
▪68% of the stressors were within the treatment area.
What were some of the major stressors to the watershed?
Buckwater Stressors: Reach T4
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Livestock
Was the main lateral
drainage in Reach
T4.
Photo Courtesy of: Wildlands Engineering
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Eutrophic Pond
Drains into Reach T4.
Buckwater Stressors: Reach T4
Photo Courtesy of: Wildlands Engineering
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Floodplain
Disconnection
ReachT4 was incised.
Buckwater Stressors: Reach T4
Photo Courtesy of: Wildlands Engineering
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Water Quality Station Setup
Water Quality Station Setup and Methods
Why use an ISCO autosampler?
▪Avoid storm chasing
▪Samples programed to collect
as flow proportional composite
sample in base or storm flow
conditions.
▪Discharge calculated based on
site specific rating curve
derived from weir equations or
dilution gauging.
▪Integrates precipitation and
stage data.
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ISCO autosampler
ISCO rain gauge
Cross-section Install stage plate Secure sampling equipment
Install ISCOs Program ISCOs
Site specific rating curve
Water Quality Station Setup and Methods
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Buckwater Reach T4 –Total Suspended Solids
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n = 37 n = 50
n = 21 n = 59 Significant
Median Change of 74%
p-value = 6.8e-5
Upstream Downstream
Buckwater Reach T4 –Total Phosphorus
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Significant
Median Change of 79%
p-value = 2.8e-9
n = 37 n = 53
n = 21 n = 60
Upstream Downstream
Buckwater Reach T4 –Total Nitrogen
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Significant
Median Change of 64%
p-value = 1.2e-13
n = 37 n = 53 n = 21 n = 60
Upstream Downstream
Buckwater Reach T4 –Total Organic Nitrogen
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Significant
Median Change of 75%
p-value = 9.2e-10
n = 37 n = 53
n = 21 n = 60
Upstream Downstream
Buckwater Reach T4 –Nitrate + Nitrite
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Significant
Median Change of 45%
p-value = 4.2e-6
n = 37
n = 53
n = 21 n = 60
Upstream Downstream
Buckwater Reach T4 –Ammonia
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Significant
Median Change of 70%
p-value = 4.2e-7
n = 37 n = 53
n = 21 n = 60
Upstream Downstream
Reach T4 –Total Fecal Coliform Bacteria
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Significant
Mean Change of 74%
p-value = 3.3e-7
n = 33 n = 55 n = 40 n = 17
Upstream Downstream
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Buckwater Site: Reach T3 (Fecal Only)
Upstream Site
Watershed Control Station
•1,336 project linear feet
•Overall drainage 141 acres
Downstream Site
Treatment Station
Reach T3 –Total Fecal Coliform Bacteria
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Significant
Median Change of 53%
p-value = 0.0015
n = 34 n = 51 n = 40 n = 33
Upstream Downstream
Summary of Results
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▪Buckwater Reach T4 demonstrated a low watershed noise case study
with reductions in nutrients and suspended solids:
▪64 –79% reduction in all pollutants in the post sampling compared to pre -construction
conditions.
▪45% reductions for Nitrate and Nitrite (NO2/NO3).
▪Decreased concentrations and variability of nutrients and solids in post restoration
conditions.
▪Attributed to stream reconnect, vegetated buffers, cattle exclusion.
▪Significant reduction in fecal coliform (53 –70% reduction) due to cattle
exclusion at both reachT3 and T4.
Moving Forward
Goals we are still working towards:
▪Include projects with different levels of signal to noise.
▪Examine effects of different restoration treatments?
▪Calculate and compare discharge and loads.
▪Analyze change in hydrologic residence times.
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DMS Water Quality Dashboard
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https://ncdms.shinyapps.io/DMS_Data_Dashboard/?_ga=2.244140805.1888177155.1629207544-1820359697.1629207544
DMS Water Quality Dashboard
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Acknowledgements
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DMS Science & Analysis
▪Periann Russell
▪Greg Melia
▪Joe Famularo
▪Lin Xu
DMS Mitigation Provider:
▪Wildlands Engineering, Inc.
Questions?
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Email: [e-mail]
https://deq.nc.gov/about/divisions/mitigation-services