Vision for the National Geospatial Framework for Surface Water

Robert M. Hirsch

Associate Director for Water

U.S. Department of the InteriorU.S. Geological Survey

What is the Geospatial Framework for Surface Water?

A standard set of Watershed Boundaries (WBD)coupled with a National Stream Network (NHD)and the Topography that dictates the flow of Water across the Land Surface (NED-H)

Vision:Follow a drop of water from where it falls on the land, to the stream, and all the way to the ocean.

What will this Accomplish:• An appropriate system for referencing of

information about:• Withdrawl Points• Discharge Points• Gage Locations• Sampling Points

• Providing logical connections: upstream, downstream, and in the watershed

Applications• Organizing river related information• Source water delineation• Spill propagation & dilution modeling• Watershed modeling • Flood wave modeling• Statistical inference of flow characteristics• Statistical inference of water quality• Monitoring network design• Interpolation schemes for flow, concentration

or transport

4 Example Applications

• Massachusetts Streamstats

• Atrazine Regression Modeling

• SPARROW - Nutrients & Hypoxia

• Streamgage Network Design

Example:

Massachusetts Streamstats Web

Application

Regression Equations• Used to estimate streamflow

statistics for ungaged sites based on basin characteristics

• Equations developed by USGS

• Large effort by users to determine basin characteristics accurately

Example Basin Characteristics• Regression equations take the form:

Q100 = 0.471A0.715E0.827SH0.472

• Drainage area is used in nearly all equations• Other common variables include:

Basin slope, relief, or mean elevationPrecipitation (mean annual; 2-year, 24-hour)Stream length or slopeLand use (forest, wetland, impervious, water)Basin shape or orientationSoils or surficial geology

Manually Determining Basin Characteristics

• 10-square mile basin takes about 24 hours

• Required time increases exponentially with watershed area

• Manual process is subject to significant error & not completely repeatable

The Massachusetts Streamstats Web Application -

• Provides published streamflow

statistics & basin characteristics for

data-collection stations

• Provides estimates of streamflow

statistics & basin characteristics for

user-selected locations

Site Selection for Low-Flow Analysis

Example Output for Ungaged Sites

Example Output for Ungaged Sites, cont’d

Benefits to Users• Results are available in minutes• A large collection of maps,

equipment, and software aren’t necessary

• The process is reproducible• Only a basic understanding of

hydrology & geographic analysis is needed

Benefits to USGS• Fewer costly information requests

• Consistent & rapid information delivery

• Fulfills goals of USGS Strategic Plan & National Streamflow Information Program

Example:

Atrazine Concentration Regression Modeling

Agricultural Use of Atrazine by County

National Regression ModelAnnual Mean Atrazine

> 1 ug/L0.5 - 1 ug/L0.01 - 0.5 ug/L< 0.01 ug/L

Predicted Annual Mean Atrazine in Source Waters for 567 Intakes

(Median prediction for each site)

> 1 ug/L0.5 - 1 ug/L0.01 - 0.5 ug/L< 0.01 ug/L

Example:

SPARROW

Spatially Referenced Regressions on Watershed

Attributes

Nitrogen Fertilizer Use in the Mississippi Basin

Annual Nitrate Flux to Gulf of Mexico

Nitrogen-loss Rate in Relation to Stream Channel Depth

TN Flux (metric tons/yr)< 100100 to 250250 to 1,000> 1,000

States

KEY

SPARROW Predictions of Total Nitrogen Flux

Percentage of the Nitrogen export form Interior Watersheds Delivered to the Gulf

Yield of Total Nitrogen Delivered to the Gulf from Incremental Drainage areas of Monitoring Stations

in the Mississippi River Basin

Example:

Design of the National Streamflow Information

Program (NSIP): Baseline Federal Network

Goals of the NSIP Baseline Federal Network• National Water Quality Networks

• Compacts/Decrees/Boarder Crossings

• Key River Basin Outflows

• Sentinel Gages

• Flood Forecast Locations

But - It needs a substantial effort to reach its full potential,

Many agencies (Federal & State) & the private sector are working together to complete the tasks.

The Geospatial Framework For Surface Water Exists

• Consensus definitions/standards (ACWI/FGDG)• Develop tools• Apply the tools to create the framework data sets• Quality assurance• Store & disseminate the framework data sets• Code features to the framework• Train users• Maintain the framework data sets

What does it take ?

NHD Problem: Drainage Density Artifacts

0

10

20

30

40

50

60

70

80

90

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

EastWestNorth

Hydrologic Unit Codes

2-digit=1st level=22 regions

4-digit=2nd level=222 subregions

6-digit=3rd level=789 basins

8-digit=4th level=2223 subbasins

10-digit=5th level

~ 22,000 watersheds

Size = 40,000-250,000 acres

12-digit=6th level

~200,000 subwatersheds

Size = 10,000-40,000 acres

Watershed Boundary DatasetNext step: Divide the Subbasins

If we didn’t have a detailed and standardized national system of Zip Codes it would be tough for the Postal Service to efficiently and reliably deliver the mail

Just as Zip code delivers the mail....

We need a detailed, standardized and hydrologically sound national system of stream and watershed addresses.

Without it, it will be tough for the scientific and engineering communities to deliver the information.

Vision

Surface Water GeospatialFramework

NHD Future

Surface Water Geospatial Framework-Vision

-what stream?-where on the stream?-drainage area?-what does it affect?-what is it affected by?

Follow a drop of Water

Future-for every reach in NHD…

• Reach catchment area defined

• Flow statistics (e.g. velocity, time of travel)

• Location of gages, DW intakes and dams

• Input to SPARROW & other models for estimation of water quality parameters

Key Spatial Water Datasets

• National Hydrography Dataset (NHD)

• Watershed boundary Dataset (WBD)

• National Elevation Dataset (NED)

• Land Cover Dataset (MRLC)

Understanding watershed characteristicsfor better watershed management

Land use

Drainage

Elevation

Boundaries

Application

Massachusetts Streamstats Web Application

Watershed Boundary DatasetWhy is it needed ?

• 8-digit Cataloging Units too large

• Need a standard nomenclature, ID’s, names, rules

•Needs to be hydrologically sound, crossing state lines

Future DirectionsExtension of web system to include additional watershed

data & model output:

• Maps of reach water quality(load, yield, concentration)

• Maps of contaminant sources

• Contaminant delivery to downstream reaches

• Downloadable data files(GIS, spreadsheet)

Watershed Boundary DatasetWhy is it needed ?

• 8-digit Subbasin Unit too large

• Need a standard nomenclature, ID’s, names, rules

•Needs to be hydrologically sound, crossing state lines

10-digit=5th level

~ 22,000 watersheds

Size = 40,000-250,000 acres

12-digit=6th level

~200,000 subwatersheds

Size = 10,000-40,000 acres

Watershed Boundary DatasetNext step: Divide the Subbasins

Needed: a stream addressing system

Zip code = watershed

Address = stream reach

10-digit=5th level

~ 22,000 watersheds

Size = 40,000-250,000 acres

12-digit=6th level

~200,000 subwatersheds

Size = 10,000-40,000 acres

Watershed Boundary DatasetNext step: Divide the Subbasins