Events in the NHD Michael Tinker September 2012

Outline

1. Linear referencing

2. Network events

3. NHD events

4. Gages, water quality stations

NWIS

Indexing workflow

5. Dams

6. Divergences

7. Water quality stations

8. Future events in the NHD

9. Wrap up

Linear networks

• Transportation

• Railroad

• Gas pipelines

• Drinking water mains

• Storm drain networks

• Sewer networks

• Rivers systems

Linear referencing

• Points on the network.

• One can always model points on the network using XY coordinates, however…

• It is desirable to model information without having to express it in XY terms.

• For example, route I-12, mile marker 47.

• Multiple attributes can be associated with linearly referenced features.

Network events

• An event is a linearly referenced feature

• Events must have:

– Route

– Measure

NHD point events

• In the NHD, events have:

– ReachCode

– Measure

EventType

Gage

Dam

Flowlines with ReachCode

Flowlines with Measure

Flowlines with ReachCodes, Events with Measures

NHDPointEventFC

EventType

# Water Quality Station

" Dam

! Gaging Station

NHD point events

National Water Information System (NWIS)

Events reference outside information

Sept 19, 2012 240,737 points

NHD point events

• Permanent_Identifier unique identifier

• ReachCode unique reach id

• Measure 0 to 100, for linear referencing

• EventType gage station, dam, diversion, water quality station

• EventDate date the event was created or last modified

Point Event Attributes

• Feature_Permanent_Identifier Permanent_Identifier of NHD feature an event is referenced to. Internal reference.

• Source_DataDescription Name of source data, e.g. NWIS, NID.

• Source_FeatureID ID of feature in the source data, e.g. NWIS site number, or NID ID.

• FeatureDetailURL link to detailed event data at the source e.g. NWIS web page for each unique site number.

Point Event Attributes

Point Events Types in the NHD Sept 19, 2012

Event Type Description Number of points

1 Gaging Station 105,400

2 Dam 60,256

3 Withdrawing Divergence Structure 25

4 General Divergence Structure 818

5 Contributing Divergence Structure 33

6 Water Quality Station 74,205

240,737

Gages

Gaging Station Event Type =1

105,400 points, as of Sept 19 , 2012

Identify gage point events in ArcMap

National Water Information System (NWIS)

National Water Information System (NWIS)

National Water Information System (NWIS)

Snapshot of NWIS Stream gages, Water Quality (QW) stations,

131,902 points, June 2011

Indexing workflow

Clip the NWIS points by HUC 4

NWIS Points in HUC 1201

Remove duplicates from NWIS clip

Hydrography Event Management Tool

Raw NWIS points

NWIS points snapped to NHD

100 meter snapping threshold

100 meter snapping threshold

50 meter move threshold

1000 meter absolute threshold

In lakes > 1000 meter distance flowline is acceptable

Placement Issues

Placement Issues

Placement Issues

Placement Issues

Dams

Dam Event Type = 2

60,256 points as of Sept 19, 2012

National Inventory of Dams (NID)

Fish Passage Decision Support System

Divergences

General Divergence Structure Event Type = 3

25 points as of Sept 19, 2012

Withdrawing Divergence Structure Event Type = 4

818 points as of Sept 19, 2012

Contributing Divergence Structure Event Type = 5

33 points as of Sept 19, 2012

Divergence data sources:

• Bureau of reclamation

• State office of engineer

• State/local water districts

• State/local water rights databases

Colorado Decision Support System

Water Quality Stations

Water Quality Station Event Type = 6

74,205 points as of Sept 19, 2012.

Water quality stations are often coincident with gages

NHDPointEventFC

EventType

# Water Quality Station

" Dam

! Gaging Station

Stream Stats Application

Stream Stats Application

Future Plans for Events

• HUC8 pour points

• “VIP” gages

– HCDN gages

– NSIP (National Streamflow Information Program)

– GAGES II (Geospatial Attributes of Gages for Evaluating Streamflow, Version II)

• Area and line events

• Better integration with USTopo

Pour Points

Pour Points

Pour Points

Pour Points

Weweantic River (Longest river – 27km)

Subbasin 01090002 Downstream Trace

Subbasin 01090002 Upstream Trace

Weweantic River (Greatest number of drainage kilometers – 472)

Subbasins 17040216 and 17040217

Area and line events

Summary

• NHD contains events which link the NHD to external information.

• The events can be used for modeling, such things as stream flows, barriers, water rights, pollution traces, heat pollution.

• Data Information Knowledge