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Water: Services

Navigation Delineation Service


The Navigation Delineation service is a service that builds upon the Navigation Service to provide an areal representation of the navigation process by linking navigated flowlines to associated areal geographies.  In most cases the primary areal feature associated with NHD flowlines are the NHDPlus catchments.  However the service is designed to be expanded in future versions to return results for other associated areal coverages such as Watershed Boundary Dataset (WBD) or Tiger Political layers.

Usage Scenarios

TMDL Watershed Characteristics

Problem Statement

Reviewing a TMDL for a single listed water and pollutant.  

Desired Information  

Upstream drainage basin watershed characteristics for land areas that drain to surface water features within 50 miles of the downstream end of the listed water. Land use, impervious surface, population density, etc. are all data layers that are desired and can be generated by overlaying the returned drainage basin with the appropriate spatial layer. NOTE: land use characteristics based on the NHDPlus dataset are returned with the basin.  

Information Returned from Service  

Drainage basin polygon with land use characteristics.


Code Samples


Parameter Datatype Required Description
pNavigationType String True 'UM' for upstream mainstem navigation
'UT' for upstream with tributaries navigation
'DM' for downstream mainstream navigation
'DD' for downstream with divergences navigation
'PP' for point-to-point navigation 
pStartComid Number True NHD flowline comid to begin navigating from. Must be greater than 0 and less than 999999999.
pStartReachcode String True NHD reach code to begin navigating from. User must provide either a comid or a reach code. If both are provided, then the comid takes precedence.
pStartMeasure Number True Measure on the NHD reach code to begin navigating from. Must be between 0 and 100 inclusive, or NULL. A value of null means that a measure will be calculated to be either the bottom or the top of the NHD flowline. (depending on whether the navigation type is upstream or downstream and whether it is a start or stop measure). 
pStopComid Number
  NHD flowline comid to stop navigating at. Must be greater than 0 and less than 999999999.
pStopReachcode String   NHD reach code to stop navigating at. User must provide either a comid or a reach code. If both are provided, then the comid parameter takes precedence.
pStopMeasure Number   Measure on the NHD reach code to stop navigating at. Must be between 0 and 100 inclusive, or NULL. 
pMaxDistance Number   Distance in KM to navigate. If pMaxDistance is not provided, then distance to travel defaults to 50 km. 
pFeatureType String   The areal feature type to associate with the flowline results and return.  The default value is 'CATCHMENT'.
pOutputFlag String   FEATURE/FLOWLINES/BOTH - Flag to indicate which geometries are returned in the output.  The default value is 'FEATURE'.
pAggregationFlag String   TRUE/FALSE - Flag to indicate whether to aggregate feature geometries in the output.  Note that the delineated geometry of the feature type is considered a single feature thus non-aggregated results will be returned as single multipolygon geometry.  The default value is 'TRUE'.
HTTP Service Notes

Additional parameters specific to HTTP services are listed in the WATERS HTTP Services documentation.


Return Object 


HTTP Service Notes 

The output format for this service is JSON with GEOJSON formatted geometries.

JavaScript Library

Function Name

HTTP Service

Resource Location
Runtime Endpoint http://ofmpub.epa.gov/waters10/NavigationDelineation.Service


Version: 3.0 1- Released: April 21, 2014

  • pMaxTime parameter removed as NHDPlus v2.1 does not support time of travel calculations at this time.

Version: 3.0 - Released: February 03, 2014

  • SOAP version of the service decommissioned.

Version: 1.0 - Released: August 31, 2009 

  • Initial Release of HTTP Service

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