RTI_WaterFALL_

RTI International
RTI International is a trade name of Research Triangle Institute. www.rti.org
WaterFALL Status
11/27/12

Michele Cutrofello Eddy
RTI International
Where we are….and where we’re going
Current ecological flow work for EDF
–Mostly focused in NC
–Assessing the hydrology and biology
–Focus on locations with biological monitoring data
Current resilience study for TNC
–Assessing changes in flow metrics and baseflow contributions to
flow as two components of a resiliency study for NC
–Summarizing results to HUC12 and HUC8 levels
Current development of a hydrologic foundation for the
southeast U.S. for SALCC
Beginning freshwater assessment pilot study for
Louisiana for TNC
RTI International
•Catchments average 1.7 km2 in NC modeled area
•58,187 modeled catchments across 21 watersheds
•Summarized to 1285 HUC12s
•Total modeled area: 100,000 km2 or 38,700 mi2
RTI International
RTI International
Calibration Notes
Variety of performance metrics evaluated
–Volume error over daily flows (#) – automated calibration
–Nash-Sutcliffe Efficiency for daily flows (#)
–Daily hydrograph (visual)
–Flow duration curves (visual)
–Monthly median and mean volumes (visual & #)
–Ecoflow Metrics (#)
General findings
–No one area or stream type consistently out-performed others
–Residuals/errors scattered; no consistent bias (that’s good!)
–Comparisons between WaterFALL and other rainfall-runoff
models for prediction of ecoflow metrics are promising
RTI International
Daily Hydrographs
Check for
general
patterns
and trends
Storm
peaks and
recessions
Order of
magnitude
agreement
Example hydrograph from the Chattahoochee
River gage near Cornelia, GA (stable stream)
Example hydrograph from the Meherrin River
gage near Lawrenceville, VA (perennial stream)
RTI International
Flow Duration Curves
Examine high,
median, and low
flow representations
by WaterFALL
Check for behavior
and magnitude
Flow duration curve (calibration period) for
Chattooga River near Clayton, GA (SBF)
Flow duration curve (calibration period) for
Falling River near Naruna, VA (PR)
RTI International
Monthly Flows
Check for
seasonality/
patterns
Seasonal
bias?
Median monthly flow comparison
(calibration period) for Alcovy River above
Covington, GA
Median monthly flow for the Tick Creek
Gage (Cape Fear Basin)
RTI International
RTI International
Ecoflow Metrics – RTI’s Percentile Version
RTI International
Ecoflow Metric Estimation Across Classes
RTI International
“Coloring In” the State with Stream Classes
RTI International
Mayo Creek “Sphere of Influence” Example
RTI International
Mayo Creek “Sphere of Influence” Example
RTI International
Mayo Creek: Pre- and Post-Alteration
RTI International
Monthly Flows at Three Points Along River
At Dam 25 km Downstream
Ex
t
r
e
m
e

L
o
w

F
l
o
w
s

Hi
g
h

F
l
o
w
s

Me
d
i
a
n

F
l
o
w
s

Unreg: PR Reg: CSI Unreg: PR Reg: PR Unreg: PR Reg: PR
8 km Downstream
RTI International
Persistence of Alterations Downstream
RTI International
Interpreting Hydrologic Metrics for Ecological
Flow Development
What metrics are important to the biology?
–Consider life cycles, flow requirements, migration….
Define the “sphere of influence”. How far downstream do the impacts
persist?
–Is the distance over which the impacts persist acceptable given
perceived benefit of the alteration?
–Does this distance drastically change based on hydrologic regime and/or
some ratio of drainage area and alteration? Can thresholds be
determined based on these characteristics?
Are certain seasons more impacted than others?
–Can regulations be set by season or month?
Are effects more prevalent at different points of the flow regime?
–Leads to the actual metric that will be used in setting regulations or
guidelines
RTI International
Stay tuned…..
Michele Cutrofello Eddy
Environmental Engineer
919.990.8458
[e-mail] (for now)
RTI’s WaterFALL™
https://waterfall.rti.org