Description of the 2002 SPARROW Models for the Midcontinental Region of North America
The SPARROW model results displayed here represent long-term mean-annual total nitrogen and total in streams of the
Midcontinental Region of North America. The simulated loads represent source inputs similar to 2002 and normalized to
long-term average hydrologic conditions for the period from 1970 to through 2012.
Documentation of the SPARROW models for the Midcontinental Area of Canada and the United States
Robertson, D.M., D.A. Saad, G.A. Benoy, I. Vouk, G.E. Schwarz, and M.T. Laitta. 2019. Phosphorus and nitrogen
transport
in the binational Great Lakes Basin estimated using SPARROW watershed models. Journal of the American Water
Resources
Association
1–25. https://doi.org/10.1111/1752-1688.12792
Saad, D.A., D.M. Robertson, G.A. Benoy, and I. Vouk, 2019, SPARROW model simulated nutrient loads in streams of the
Midcontinental Region of Canada and the United States, 2002 Base Year. U.S. Geological Survey, data release. Available
online at: https://doi.org/10.5066/P9ODSQYB.
Vouk, I., R.S. Burcher, C.M. Johnston, R.W. Jenkinson, D.A. Saad, J.S. Gaiot, G.A. Benoy, and D.M. Robertson, 2018a.
Data and procedures used to develop inputs for nutrient SPARROW models throughout the midcontinental region of Canada
and the United States. National Research Council of Canada. 39 p. plus appendices. Available online at: http://doi.org/10.4224/23004810.
SPARROW Surface Water-Quality Modeling Web Pages
National Website: https://water.usgs.gov/nawqa/sparrow/
Regional Website: https://www.usgs.gov/centers/wisconsin-water-science-center/science/sparrow-watershed-modeling-great-lakes-ohio-upper?
Documentation of the modeling tool SPARROW (SPAtially Referenced Regression On Watershed
attributes)
Schwarz, G.E., A.B. Hoos, R.B. Alexander, and R.A. Smith, 2006. The SPARROW Surface
Water-Quality Model: Theory, Application, and User Documentation. U.S. Geological Survey
Techniques and Methods Report, Book 6, Chapter B3. https://pubs.usgs.gov/tm/2006/tm6b3/;
Preston, S.D., Alexander, R.B., Woodside, M.D., and Hamilton, P.A., 2009, SPARROW MODELING
- Enhancing Understanding of the Nation's Water Quality: U.S. Geological Survey Fact Sheet
2009-3019, 6 p. https://pubs.usgs.gov/fs/2009/3019/
The relationship between the scale of reporting of model results and uncertainty:
Model results can be displayed at several watershed scales.
The smallest scale that could be used for reporting is the catchment scale
at which model computations are made. For the Midcontinent models
these are NHD/NHN catchments with typical watershed size of about 2.5 square
kilometers. Results can be aggregated up to larger scales for reporting:
tributary outlet, HUC8/Sub-sub drainage area (typical watershed size is
3,850 square kilometers), state, or selected watersheds within the modeled area.
The SPARROW model is, in theory, scale independent. However, the uncertainty associated
with SPARROW predictions is expected to increase for drainage basin sizes smaller
than those of stream monitoring sites used to calibrate the model. For the Midcontinent nutrient models, the drainage areas of the smallest calibration sites are typically in the range of
10 to 100 square kilometers. The uncertainty associated with incremental load and yield predictions at the catchment
scale is therefore expected to be larger than the uncertainty associated with predictions at larger scales.
Incremental Load
The predicted mean annual load of the constituent (kilograms per year) leaving a stream reach that reflects only those sources contributed from within the incremental drainage area of that reach. The incremental load value includes the effects of in-stream attenuation processes associated with one half of the incremental reach length. Incremental drainage areas are represented here as “catchments”.
Accumulated Load (often referred to as "Total Load")
The predicted mean annual load of the constituent (kilograms per year) leaving a stream reach that reflects the accumulated mass of the constituent contributed by all sources in the total drainage area upstream of the reach outlet. The accumulated load value includes the effects of in-stream attenuation processes in all upstream reaches.
Aggregated Load
For results grouped by 8-digit HUC/Sub-sub drainage area, tributary outlet, major drainage area or state/province, aggregated load represents the sum of incremental loads for those selected areas.
Incremental Yield
The Incremental Load divided by the incremental drainage area
of the reach. Units are kilograms per square kilometer per year.
Accumulated Yield
The Accumulated Load divided by the total drainage area upstream of the reach outlet. Units are kilograms per square kilometer per year.
Aggregated Yield
The Aggregated Load divided by the sum of the "grouped by" incremental drainage areas. Units are kilograms per square kilometer per year.
Delivered Incremental Load
Incremental load multiplied by the delivery fraction.
Delivery fraction is defined below.
Delivered Accumulated Load
Incremental load multiplied by the delivery fraction. Delivery fraction is defined below.
Delivered Aggregated Load
For results grouped by 8-digit HUC/ Sub-sub drainage area, tributary outlet, major drainage area or state/province, delivered aggregated load represents the sum of delivered incremental loads for those selected areas. Delivery fraction is defined below.
Delivered Incremental Yield
The Delivered Incremental Load divided by the incremental drainage area of the reach. Units are kilograms per square kilometer per year.
Delivered Accumulated Yield
The Delivered Accumulated Load divided by the total
drainage area upstream of the reach outlet or total of the “grouped by” area. Units are kilograms
per square kilometer per year.
Delivered Aggregated Yield
The Delivered Aggregated Load divided by the sum of the “grouped by” incremental drainage areas. Units are kilograms per square kilometer per year.
Delivery Fraction (definition)
The fraction of the load leaving a reach that is not attenuated or removed by natural processes during downstream transport to a specified downstream target reach. A delivery fraction of 1 indicates that 100 percent of the load leaving the reach is delivered to the downstream target.
Please note: For delivered results shown here, the downstream targets represent the Great Lakes, Lake Winnipeg and the outlets of the Upper Mississippi and Ohio River Watersheds.
USGS Data Disclaimer:
Unless otherwise stated, all data, metadata and related
materials are considered to satisfy the quality standards relative to the purpose for which
the data were collected. Although these data and associated metadata have been reviewed for
accuracy and completeness and approved for release by the U.S. Geological Survey (USGS),
no warranty expressed or implied is made regarding the display or utility of the data for
other purposes, nor on all computer systems, nor shall the act of distribution constitute
any such warranty.
USGS Software Disclaimer:
This software has been approved for release by the
U.S. Geological Survey (USGS). Although the software has been subjected to rigorous review,
the USGS reserves the right to update the software as needed pursuant to further analysis
and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government
as to the functionality of the software and related material nor shall the fact of release
constitute any such warranty. Furthermore, the software is released on condition that neither
the USGS nor the U.S. Government shall be held liable for any damages resulting from its
authorized or unauthorized use.
USGS Product Names Disclaimer:
Any use of trade, firm, or product names is for
descriptive purposes only and does not imply endorsement by the U.S. Government.
This web application functions best in Chrome, Firefox, or Safari. Internet Explorer works but with slower performance.
This web application has been made possible by the following open-source projects:
Lobipanel
https://github.com/arboshiki/lobipanel
Boostrap
Select https://silviomoreto.github.io/bootstrap-select
Version v1.0.0
Link to SPARROW REST Services:
SPARROW
TEST REST Services
