National Hydrography Dataset (NHD) HIS Symposium March 8 Prepared & Presented by Horizon Systems Corporation Sponsored by US Environmental Protection Agency

Our Agenda  What is NHD? Content Content Capabilities Capabilities Status and Data Access Status and Data Access  What is NHDPlus? Data to Support Analysis & Modeling Data to Support Analysis & Modeling Data Availability Data Availability  Questions

A framework dataset that includes: Hydrographic features for making mapsHydrographic features for making maps A national stream addressing systemA national stream addressing system A modeling network for navigatingA modeling network for navigatingupstream/downstream A maintenance infrastructureA maintenance infrastructure User updatesUser updates Distributed format compatible with ArcHydroDistributed format compatible with ArcHydro What is the National Hydrography Dataset (NHD)? 1 2 3

What’s in the NHD? 40+ hydrographic feature types Permanent “Features” -- Reaches ( Stream Network, Artificial Flow Paths through Waterbodies, Coastlines, Waterbody Areas) Permanent, Public Ids - Reach Codes Seamless National Dataset Multi-Scale – 1:100K, 1:24K, and higher

NHD Comes in Three Sizes Medium Resolution 1:100,000 scale Lower 48 + HI 2112 Sub-basins High Resolution 1:20K, 24K, 63K 50 States + PR/VI +/ Sub-basins Local Resolution > High Res Vermont ~17 Sub-basins

Full NHD - Linear Stream Network - Waterbodies - Landmark Features - Feature Names & Attributes

Full NHD Stream Network - Feature Typing - Basic Attribution - Confluence-to- Confluence Feature Confluence Feature Delineation Delineation - Topology Dependent - Scale-Dependent

Full NHD Stream Network Reaches - Permanent “Features” with Public Identifiers with Public Identifiers - Scale Independent - Changes Tracked - Hydrologic-based Delineation Delineation - Linear Referencing Framework Framework

NHD Applications Drawing the “Blue Lines” Modeling & Analysis Mapping & Inventory Linear/Areal Referencing

Stream Network Reaches: The Linear Referencing Framework

Coastlines Connected to the Network Coastline

Waterbody Reaches: The Area Referencing Framework

Addresses on Linear Reaches  Each linear reach is one addressable unit - a ‘street’  Addresses are proportional ‘street’ numbers from bottom to top

Linking Data to the NHD Area Links Waterbody Reach: shape Linear Links Linear Reach: From Measure: 0.0 To Measure: Linear Reach: Measure: Point Links

Navigate with Network Geometry

8.7 miles Drinking Water Intake Timber Production WQ Monitoring Station Drinking Water Intake Linear Referencing _______ Upstream & Downstream Analysis WQ Monitoring Station Drinking Water Intake Timber Production Flow Gage State Designated Priority Waters 303(d) TMDL Waters

Where to Learn More

Where to Get the Data

NHD Medium Resolution Status

NHD High Resolution Status Available In Work Planned

NHD Local Resolution Status

NHD Plus – What is it?  Greatly Improved 1:100K NHD  A Set of Value Added Attributes  Elevation-based Catchment for Each Segment in the Stream Network  Catchment Characteristics  Flow Direction and Flow Accumulation Grids  NHD Network Node Elevations  Stream Gages Linked to Stream Network  Flow Volume & Velocity Estimates for Each Segment in the Stream Network

Acknowledgements EPA Project Team Tommy Dewald Horizon Systems Cindy McKay Jen Hill Bob Deffenbaugh USGS WRD Rich Moore Craig Johnston Al Rea RTI International. Tim Bondelid

1:100K NHD Improvements  Stream and waterbody name corrections and additions  Correction to stream network coordinate order (pointing downstream)  Correction of gaps, overlaps, overshoots, etc. in network geometry  Independent QAQC of flow table.  Flow table and geometry agree.

The Value-Added Attributes:  A set of two dozen network characteristics  Based solely on native NHD content  Created with software  Built using the national NHD  Provides alternatives to navigating with the geometry

Navigation Analysis Display Stream Order Waterbody Identifier Waterbody Type Upstream Miles Distance to Sink Drain Stream Level Link-Node Traversal Hydrologic Sequence Terminal Identifiers Level Path Identifiers Independent Flow Table Generalization Attribute Value Added Attributes

e.g. Strahler Stream Order The smallest permanent streams are called "first order". Two first order streams join to form a larger, second order stream; two second order streams join to form a third order, and so on. Smaller streams entering a higher-ordered stream do not change its order number. Strahler VAAs for Analysis

Common Problems with Geometric Navigation

Flow Table Network Navigation  Flow relationships between network features “Feature A flows to Feature B”  Can be use totally independent of geometry

Simple Query Network Navigation  A Series of Attributes Computed From the Flow Table and the Geometry  Once Computed, Independent of Geometry and GIS  Navigate with SQL Query

VAAs Help with NHD Displays

Importance of the VAAs  Easier answers to network questions  Fast, simple, reliable network navigation Fast, sequential routing Fast, sequential routing Simple SQL queries Simple SQL queries Link Node routing Link Node routing  Provide some commonly used attributes Stream Order Stream Order Hydrologic Sequence Hydrologic Sequence Stream Path Identifier Stream Path Identifier  Establish the integrity of the network

Catchments  The portion of the land surface that drains to a network segment  Catchments built using 30m National Elevation Dataset (NED)  Generated using the “New England Method” (NEM)  Outputs include catchments in grid format and as polygons

The NEM Approach  NHD stream network burned into NED  NHD network waterbodies used to bowl the NED  Where available, Certified Watershed Boundaries (HUC10 & 12) used to build walls  Where possible, sinks placed at ends of “true” isolated networks

Catchments

Catchment Validation  Stream Gage drainage area measurements Is the drainage area size correct?  Stream Gage drainage area boundaries Is the drainage area in the correct location?

Catchment Characteristics  Mean Annual Temperature (Prism)  Mean Annual Precipitation (Prism)  % of each Land Use from NLCD

Catchment Process By-Products  Flow Accumulation Grid  Flow Direction Grid  Stream Network Node Elevations

Elevation Smoothing

USGS Flow Gages Linked to NHD  NWIS site location snapped to NHD  USGS WRD district offices reviewed and adjusted, as needed  Revised NHD locations converted to an event table with Reach Code and Measure

Flow Estimates Unit Runoff Method  Estimate average annual unit runoff by 8- digit HUC (sub-basin) Apply distance-weighted Average of Annual Unit Runoff for USGS NLCD Gages; simplified “zone of influence” Apply distance-weighted Average of Annual Unit Runoff for USGS NLCD Gages; simplified “zone of influence” QA Using USGS runoff isopleth map QA Using USGS runoff isopleth map

 Estimate Drainage Area (DA) for Each NHD segment  Compute incremental segment runoff Delta Q(cfs) = DA(sq km) * Unit Runoff (cfs/sq km) Delta Q(cfs) = DA(sq km) * Unit Runoff (cfs/sq km)  Route and accumulate incremental flows to estimate mean annual flow by segment  QA by comparing to USGS gage mean annual flows Flow Estimates Unit Runoff Method (cont)

 Flow estimates developed using mean annual flows at HCDN gages  Multiple regression technique with coefficients by hydrologic region  Independent variables: Cumulative Drainage Area (DA) Cumulative Drainage Area (DA) Mean annual temperature (MAT), from PRISM Mean annual temperature (MAT), from PRISM Mean annual precipitation (MAP), from PRISM Mean annual precipitation (MAP), from PRISM  Mean Annual Flow = f(DA, MAT, MAP) Flow Estimates Vogel, et al Method

 NHD Plus implementation uses catchment-based DA’s, PRISM data overlaid on catchments  Reference: Vogel, R.M., Wilson, I.W., Daly, C Regional Regression Models of Annual Streamflow For the United States. Journal of Irrigation and Drainage Engineering. Flow Estimates Vogel, et al Method (cont.)

Velocity Estimates  Inputs: Drainage area, stream segment slope, mean annual discharge  Future QAQC Possibilities: USGS Time of Travel Database  Reference: Jobson, H. E Prediction of Travel Time and Longitudinal Dispersion in Rivers and Streams. USGS Water Resources Investigations Report

NHD Plus – Components  Greatly improved 100K NHD  Value Added Attributes  Elevation-based Catchment  Catchment Characteristics  Flow Direction and Flow Accumulation Grid  NHD Network Node Elevations  Stream Gages Linked to Stream Network  Flow Volume & Velocity Estimates

“Dynamically” Define Drainage Areas

Quad Density Artifacts in NHD

NHD with Flow > 2 cfs: Hydrologic Equity

Production Map for: Catchments, Grids, and Node Elevations 20

E 04W NHDPlus Production and Distribution Units Hydrologic Regions 20

Questions?