Transcript Presentation Template

NHD Flow and Velocity Project
Greg Schwarz, Reston, VA
Alan Rea, Boise, ID
U.S. Department of the Interior
U.S. Geological Survey
Reston, Virginia
(703)648-5718
[email protected]
Needed: Estimates of flow and velocity
for every reach in NHD
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Useful for determining:
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Dilution of pollutant loadings
Travel time between pollution sources and water
intakes
Pollution attenuation with distance
Proposal
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For every NHD reach, estimate 
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Long-term mean annual flow and velocity
Long-term mean monthly flow and velocity
Long-term variance of annual and monthly flow
and velocity
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Derive 10th and 90th percentile flow estimates
7Q10 flow
Measure of statistical accuracy for each estimate
Methodology
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Statistical approach
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Flow estimates best fit the available data
Provides a basis for estimating the accuracy of each estimate
Mass balance
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Ensures that flow below a confluence equals the sum of the
flows entering the confluence
Estimates of non-point pollution concentration derived by
dividing non-point pollution load by flow are valid for
arbitrarily small basins
Approach
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Three pilot projects
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Arkansas-White-Red River Basin flow pilot
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Region of influence regression method
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Flow is correlated with basin attributes across a group of
basins having similar characteristics.
Large-scale RF1 flow pilot
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Spatially Referenced Regression (SPARROW) model of
flow applied to all RF1 streams
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Simple process oriented model incorporating flow
routing from the landscape to RF1 channels.
Flow accumulates according to the defined reach
network.
Approach (continued)
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Pilot to estimate velocity for every reach in RF1
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Regression method (Jobson, 1996)
Time of travel from dye studies
Relate to reach characteristics
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flow
slope
The Pilots are Complementary
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Arkansas-White-Red pilot provides an
opportunity to gain experience with NHD and
NED.
Large-scale RF1 pilots will investigate the
diverse processes required to adequately model
flow and velocity across the entire nation.
Arkansas-White-Red Pilot
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Initially computing basin characteristics using
EDNA
Will be used for first-run model development
Initial model calibration
Topographic Basin Characteristics
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Basin area
Mean Basin elevation
Basin relief
Avg. basin slope
Percentage of area with slope >= 30%
Synthetic reach slope, node elevations
Thematic Basin Overlays
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Mean annual precipitation (PRISM)
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Mean annual temerature (PRISM)
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Land cover percentages from NLCD, 9 general
categories
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Area-weighted average soil properties from STATSGO
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Water use by 8-digit HUC
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Percent area of playas / sand dune regions (AWR only)
Full Scale NHD Project
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Apply what is learned from the pilots to develop
regression-based flow and velocity models for
the entire NHD network.
Data Needs
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NHD reach locations for:
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Approximately 4,000 gaging stations with 20 years of
record since 1970
76,000 reservoirs from the National Inventory of
Dams (NID)
6,600 drinking water intakes
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Not required for model estimation but included to provide
functionality to the NHD project results.
Other Data Needs
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Long term mean annual and monthly flow, and
variance of annual and monthly flow for over
4,000 gaging stations with 20 years of record
since 1970.
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Data will be compiled from the NWIS data base.
Compile over 3,000 velocity measurements from
USGS time of travel studies.
Other Data Needs
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Basin boundaries for every NHD reach
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Ongoing effort to derive basin boundaries for every
NHD reach having an identified flow direction using
the 30m NED.
Reach slope
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Determine from NED.
Other Data Needs
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Climate loadings
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Precipitation and temperature estimates taken from
the Prism climate model.
Flow diversions and consumptive use
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Water use estimates by hydrologic unit apportioned
to reaches on the basis of land use from the NLCD.
Final Products
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Reach locations for gaging stations, reservoirs, and
drinking water intakes.
Long-term mean annual and monthly flow and velocity
estimates, with estimates of accuracy, for every reach
in NHD.
Estimates of 10th and 90th percentile annual and
monthly flows and velocities, and 7Q10 flow, with
estimates of accuracy, for every reach in NHD.
Results will be made available via the internet.
Estimates will be revised periodically as data sets
improve.