Comparing Water Quality Functional Uplift Outcomes from Common Models Direct Measurement Using the SQTLinGregstreamconf2018

Department of Environmental Quality
NC Division of Mitigation Services (DMS)
Lin Xu
Greg Melia
Comparing Water Quality Functional Uplift Outcomes from
Common Models and Direct Measurement Using the Stream
Function Quantification Tool (SQT) : A Case Study
EcoStream 2018
Department of Environmental Quality
EcoStream 2018
Stream Function Pyramid Framework
In April 2008, the United States Army Corps of Engineers (USACE) and the United States Environmental
Protection Agency (EPA) jointly issued regulations clarifying compensatory mitigation requirements for
Department of the Army permits (33 C.F.R. §332/40 C.F.R. §230):
“…With this rule, we are encouraging the use of functional and condition assessments to determine the
appropriate amount of compensatory mitigation needed to offset authorized impacts, instead of relying
primarily on surrogate measures such as acres and linear feet.”
The Final Rule stated:
“…In cases where appropriate functional or condition assessment methods or other suitable metrics are
available, these methods should be used where practicable to determine how much compensatory
mitigation is required (33 C.F.R. §332.3FR Vol 73, 19633).”
Department of Environmental Quality
EcoStream 2018
Stream Function Pyramid Framework
Department of Environmental Quality
EcoStream 2018
Stream Function Quantification
Tool
(SQT)
Determine numerical difference between
existing stream condition and proposed
condition
Link restoration activities to changes in
stream functions
Estimate restoration potential
Functional Category Function-Based
Parameters Measurement Method
Hydrology
Catchment Hydrology Curve Number
Reach Runoff
Curve Number
Concentrated Flow Points
Soil Compaction
Hydraulics Floodplain Connectivity Bank Height Ratio
Entrenchment Ratio
Geomorphology
Large Woody Debris LWD Index
# Pieces
Lateral Stability
Erosion Rate (ft/yr)
Dominant BEHI/NBS
Percent Streambank Erosion (%)
Riparian Vegetation
Left Canopy Coverage (%)
Right Canopy Coverage (%)
Left Riparian Vegetation Width (ft)
Right Riparian Vegetation Width (ft)
Left Basal Area (sq.ft/acre)
Right Basal Area (sq.ft/acre)
Left Stem Density (stems/acre)
Right Stem Density (stems/acre)
Bed Material Characterization Size Class Pebble Count Analyzer (p-
value)
Bed Form Diversity
Pool Spacing Ratio
Pool Depth Ratio
Percent Riffle
Aggradation Ratio
Sinuosity Plan Form
Physicochemical
Temperature Temperature (°F)
Bacteria Fecal Coliform (Cfu/100 ml)
Organic Carbon Leaf Litter Processing Rate
Percent Shredders
Nitrogen Monitoring (mg/L)
Phosphorus Monitoring (mg/L)
Biology Macros Biotic Index
EPT Taxa Present
Fish North Carolina Index of Biotic Integrity
Department of Environmental Quality
EcoStream 2018
Physiochemical Function
The nutrient (nitrogen and phosphorus) parameter is included in both the BMP Routine
and the reach condition assessments in SQT.
SQT suggests to use the Jordan/Falls Lake Stormwater Nutrient Load Accounting Tool
(JFSLAT), if a BMP is being installed.
Four common water quality models are selected and results of model runs are
compared with direct in-stream monitoring results for a DMS mitigation project.
Department of Environmental Quality
EcoStream 2018
Heath Dairy Road Restoration
Site
Cape Fear River Basin
Provides 7,791 LF of stream
restoration, 960 LF of enhancement
and 636 LF of preservation
Construction completed in 2013,
and current in year 4 monitoring
NCSU Water Group conducted pre
and post restoration monitoring
Department of Environmental Quality
EcoStream 2018
Water Quality Models
Two Export Coefficient Models
•DMS tool for Quantifying Benefits to Water Quality from Livestock Exclusion and
Riparian Buffer Establishment for Stream Restoration (DMS)
•Total Nitrogen (TN) and Total Phosphorus Loading Calculation Worksheet –
Piedmont of the Tar-Pamlico River Basin (DWR)
Two Storm Water Based Models
•Jordan/Fall Lake Stormwater Nutrient Load Accounting Tool (JFSLAT) (DWR &
NCSU BAE)
•Stormwater Nutrient Accounting Tools (SNAP) (DWR)
Department of Environmental Quality
EcoStream 2018
Back Creek Reach –Heath Dairy
•Catchment size –1.08 sq mi,
buffer planted area –6 ac, and
lateral drainage area –52 ac
•Predominant agricultural land
use (55%, mostly pasture)
North Branch Reach –Heath Dairy
•Catchment size –1.14 sq mi,
buffer planted area –6.04 ac,
and lateral drainage area –17 ac
•Predominant agricultural land
use (60%, mostly pasture)
Department of Environmental Quality
EcoStream 2018
Back Creek Reach -Water Quality Models Results and Monitoring
Data
TN (mg/L)
Pre-restoration
TN (mg/L)
Post-restoration
%
Change
TP (mg/L)
Pre-restoration
TP (mg/L)
Post-restoration
%
Change
Tar-Pam Nutrient Loading
Calculation Worksheet 1.89 1.83 3.2 0.48 0.46 4.2
JFLSAT
2.07 2.02 2.4 0.55 0.54 1.8
SNAP
1.71 1.63 4.7 0.34 0.33 2.9
Monitoring Data
5.59 2.29 59.0 1.97 0.48 75.6
Department of Environmental Quality
EcoStream 2018
North Branch Reach -Water Quality Models Results and
Monitoring Data
TN (mg/L)
Pre-restoration
TN (mg/L)
Post-restoration
%
Change
TP (mg/L)
Pre-restoration
TP (mg/L)
Post-restoration
%
Change
Tar-Pam Nutrient Loading
Calculation Worksheet 1.76 1.74 1.1 0.45 0.45 0
JFLSAT
1.74 1.73 0.5 0.44 0.44 0
SNAP
1.69 1.68 0.5 0.31 0.31 0
Monitoring Data
5.51 3.39 38.5 1.81 0.80 55.8
SQT Application –BMP Routine
Department of Environmental Quality
EcoStream 2018
Not Functioning (NF): 0.0 -0.29
Functioning at Risk (FAR): 0.3 -0.69
Functioning (F): 0.7 -1.0
Department of Environmental Quality
EcoStream 2018
SQT Physicochemical Function Application
Back Creek Reach
TN Scores TP Scores Overall Score
Tar-Pam Nutrient Loading
Calculation Worksheet
Pre-restoration 0.33 0 0.16
Post-restoration 0.34 0 0.17
JFLSAT Pre-restoration 0.29 0 0.14
Post-restoration 0.30 0 0.15
SNAP Pre-restoration 0.37 0 0.19
Post-restoration 0.39 0 0.20
Monitoring Data Pre-restoration 0 0 0
Post-restoration 0.24 0 0.12
Not Functioning (NF): 0.0 -0.29
Functioning at Risk (FAR): 0.3 -0.69
Functioning (F): 0.7 -1.0
Department of Environmental Quality
EcoStream 2018
SQT Physicochemical Function Application
North Branch Reach
TN Scores TP Scores Overall Score
Tar-Pam Nutrient Loading
Calculation Worksheet
Pre-restoration 0.36 0 0.18
Post-restoration 0.36 0 0.18
JFLSAT Pre-restoration 0.36 0 0.18
Post-restoration 0.37 0 0.19
SNAP Pre-restoration 0.38 0 0.19
Post-restoration 0.38 0 0.19
Monitoring Data Pre-restoration 0 0 0
Post-restoration 0.10 0 0.05
Not Functioning (NF): 0.0 -0.29
Functioning at Risk (FAR): 0.3 -0.69
Functioning (F): 0.7 -1.0
Department of Environmental Quality
EcoStream 2018
Conclusions
Model Limitations –Catchment Size, Nutrient EMC, Nutrient Removal Mechanism
SQT Limitation –Reference Condition, no Change / Improvement
Going Forward
Testing Additional Models, like EPA’s STEP
Department of Environmental Quality
EcoStream 2018
Questions