**DRAFT**

**September 12, 2000**

**FEDERAL STANDARDS FOR DELINEATION OF**

**HYDROLOGIC UNIT BOUNDARIES**

**TABLE OF CONTENTS\
**

**1. INTRODUCTION**

1.1 Purpose
...................................................................... 4

1.2 Background
................................................................. 4

**2. COORDINATION**

2.1 FGDC Spatial Water Data Subcommittee ..............................5

2.2 State Coordination
.........................................................6

**3. DEFINITIONS**

3.1 Hydrologic Unit Definitions
.............................................6

3.2 Geospatial Definitions
................................................... 7

**4. CRITERIA TO DELINEATE HYDROLOGIC UNITS**

4.1 General Criteria
............................................................9

4.2 Hydrologic Boundaries
....................................................9

4.3 Number of Subdivided Hydrologic Units..............................
10

4.4 Size of Hydrologic Units
.................................................10

4.5 Classic Hydrologic
........................................................ 11

4.6 Remnant Areas
............................................................ 11

4.7 Non-contributing Areas
................................................\...12

4.8 Reservoirs and Natural Lakes
............................................12

4.9 Diverted
Waters............................................................13

4.10 Coastal
Areas...............................................................13

**5. MAPPING AND DELINEATION PROCESS**

5.1 Base Maps, Map Scale and Map Accuracy ............................13

5.2 Source maps
................................................................14

5.2.1 Base Maps
...........................................................14

> 5.2.2 Hydrologic Unit Maps
> .............................................14

5.2.3 Reference
Maps..................................................... 14

5.2.4 Digital
Data.......................................................... 15

5.3 Map Delineation
Process................................................\....15

5.4 Manual Method
.............................................................15

5.5 Automated Methods

5.5.1 On-Screen Mapping and Digitizing..............................16

5.5.2 Hydrologic Modeling from Digital Elevations...............\...16

5.6 Updating and Revising Hydrologic
Units.................................17

**6. CODING AND NAMING**

6.1 Hydrologic Unit
Levels......................................................17

6.2 Coding Watersheds and
Sub-watersheds..................................17

6.3 Hydrologic Unit Naming
Protocol.........................................18

6.4 Coding at International
Borders............................................19

**7. GEOSPATIAL DATA STRUCTURE**

7.1
Digitizing......................................................................19

7.2 File
Format....................................................................19

7.2.1 File
Names............................................................19

7.2.2 Projection of
Coverage...............................................19

7.2.3 Exporting and
Compression.........................................20

7.2.4 FTP Posting and
Mailing..........................................\...20

7.3 Attribute Table
Structure..................................................20

7.3.1 Polygons (.pat) Attribute Scheme................................
20

7.3.2 Line Work (.aat) Attribute Scheme.............................. 21

**8. QUALITY ASSURANCE AND QUALITY CONTROL**

8.1 Quality
Control.............................................................21

8.2 Editing Checklist
......................................................... 21

8.3 Geospatial Data Certification
............................................22

**9.
METADATA**.....................................................................23

**10. APPENDICES**

**Appendix A: Illustrations**

> Exhibit 1 Hydrologic Unit Hierarchy.................................24
>
> Exhibit 2 Delineation of Major Lake as Hydrologic Unit..........25
>
> Exhibit 3 Non-contributing Watershed................................26
>
> Exhibit 4 Sample of Classic Watershed...............................27
>
> Exhibit 5 Watershed Delineation Within a Sub-basin............\...28
>
> Exhibit 6 Sub-Watershed Boundary Following a Ridge Line .....29
>
> Exhibit 7 Sub-Watershed Boundary Crossing Major River........30
>
> Exhibit 8 Incorrect Illustration of Boundary Crossing River.......31

**Appendix B:
Acronyms**......................................................\....32

**Appendix C: Tables**

> Figure 1 Sample Edit and Quality Control Checklist...............32

Figure 2 Sample Supplemental Process Notes.......................33

> Figure 3 Sample Hydrologic Unit Metadata Template ............34

**1. INTRODUCTION**

1.1 Purpose.

This document establishes interagency standards and guidelines for
delineating hydrologic unit boundaries and creating a national Watershed
Boundary Dataset (WBD). The standards are to be used by agencies and
tribes for developing a single, seamless, nationally consistent, and
accurate geospatial database of hydrologic units based on scientific
hydrologic and mapping principles.

This standard provides a consistent catalog of terminology and
definitions to ensure uniform interpretation of information across the
agencies, tribes and organizations that develop and use hydrologic unit
feature data and applications. The standard will enable a variety of
users from different agencies and programs to more efficiently share
information and resources, contribute to an overall coordinated
watershed management approach, and assure the geospatial database is
usable with other related GIS databases.

The criteria and methods for hydrologic unit selection and boundary
delineation will permit standardized hydrologic units to be used by a
diverse group of users serving multi-agency programs. Some examples
include watershed management, water quality initiatives, watershed
modeling, resource inventory and assessment, and total maximum daily
load processes.

Once the delineation of watersheds and sub-watersheds is completed for
the nation, the Geographic Information System (GIS) layers and
associated maps will be reasonably stable and modified through a defined
maintenance schedule.

1.2 Background.

A standard Hydrologic Unit system was first developed in the mid-1970\'s
by the U.S. Geological Survey under the sponsorship of the Water
Resources Council. This system divided the country into 22 Regions, 222
Sub-regions, 789 Basins, and 2,223 Sub-basins based on surface
hydrologic features. A hierarchical hydrologic unit code containing 2
digits for each of the four levels were assigned to identify the
hydrologic units.

The 8-digit hydrologic units are standardized and broadly used; however,
the areas are too large to adequately serve many water-resource
investigations, resource analysis and management needs. For example, the
focus of many water resource issues is based upon pollutant loading and
land-surface processes, and the cumulative effects of pollution over
place and time. Management of these issues requires working with
hydrologic units in smaller sizes than those defined by the 8-digit
hydrologic units. Programs requiring smaller hydrologic units include
State River Basin Management Plans, the Natural Resource Conservation
Service (NRCS) conservation and watershed programs, Forest Service
watershed management programs, and various programs in the Environmental
Protection Agency, Office of Water.

The NRCS is responsible for working with landowners to protect, improve
and sustain natural resources on private lands. The NRCS completed
mapping watersheds in the early 1980\'s on small-scale state base maps
for use in natural resource planning. The NRCS has made significant
contributions to the development of a national standardized geospatial
database of watershed and sub-watershed boundaries. To promote a
standardized criterion for hydrologic unit selection and delineation,
the NRCS developed a National Instruction 170-304 in 1992 that served as
the agency\'s policy for delineating and digitizing watershed and
sub-watersheds. In the mid-1990\'s, the NRCS began a national initiative
to delineate and digitize watersheds and sub-watersheds. The NRCS
updated the policy guidelines in 1995 incorporating changes from
internal and external reviews.

The U.S. Forest Service and the Bureau of Land Management (BLM) are the
primary land management agencies of federal lands in the U.S. Both
agencies are delineating and digitizing watersheds and sub-watersheds on
public lands. Delineation\'s of hydrologic units of federally
administered public lands served administrative purposes but were not
universally based on hydrologic criteria, and were often developed
without full coordination between federal or state agencies.

The USGS and member agencies of the Federal Geographic Data Committee
(FGDC), Spatial Water Data Subcommittee have been coordinating and
conducting a series of statewide workshops to promote the development of
a nationally consistent hydrologic unit coverage. The USGS is assisting
NRCS in the review and certification of hydrologic units. The USGS, EPA
and the National Weather Service are researching techniques to employ
digital elevation data for producing hydrologic unit delineation\'s.

The NRCS, Forest Service and BLM have worked with the USGS, other
federal and state agencies, tribes, and with the FGDC, Spatial Water
Subcommittee to establish these \"Federal Standards For Delineation of
Hydrologic Unit Boundaries\". This standard builds upon the original
NRCS National Instruction, and establishes the principles and standards
that federal agencies should follow in making subdivisions of the
8-digit USGS sub-basin hydrologic units. These standards are not agency
specific, and have been agreed upon by member agencies of the FGDC,
Spatial Water Data Subcommittee.

**2. COORDINATION**

**2.1 FGDC Spatial Water Data Subcommittee.**

The Subcommittee on Spatial Water Data was chartered and sponsored by
the Advisory Committee on Water Information (ACWI), and the FGDC. The
Spatial Water Data Subcommittee coordinates spatial water data and
information activities among all levels of government and the private
sector. Spatial water data includes information about streams,
hydrologic units, lakes, ground water, coastal areas, precipitation and
other hydrologic information related to water resources.

Federal agencies having major involvement in the development and
application of hydrologic units and water resources management
responsibilities are encouraged to participate as members of the Spatial
Water Data Subcommittee.

The Spatial Water Data Subcommittee assists the ACWI and FGDC by
facilitating the exchange and transfer of water data, establishing and
implementing standards for quality, content and transfer of water data,
and coordinating the requirements and the collection of spatial data to
minimize duplication of efforts.

**2.2 State Coordination.**

The delineation of hydrologic units into \"watersheds\" and
\"sub-watersheds\" is an opportunity to develop a consistent and common
nation-wide geospatial database for interagency sharing, and for
improving federal, state, and local uses of hydrologic units. An
Interagency Hydrologic Unit Group should be formed within a State. One
person from either a state or federal agency should act as a
coordinator. The group should promote the development and maintenance of
a hydrologic unit geospatial database, and provide a forum for
coordination and consensus among Federal, State, and local agencies
(including adjoining States), and watershed entities.

All states within a sub-basin should coordinate their delineation work.
This coordination should cover the locations of 10 and 12-digit outlet
points, the size of the watersheds and sub-watersheds, and the coding
sequence within each level of the hydrologic unit hierarchy. The mapping
and edge-matching of hydrologic boundaries crossing county and state
boundaries must be coordinated to assure a nationally consistent
database is created.

State coordination can help to prioritize the delineation of hydrologic
units and define their uses and applications. The participants should
agree to establish procedures for quality control, coordination and
management of the hydrologic unit delineation project. Opportunities to
obtain financial support, in-kind services and cost sharing should be
explored.

Differences in watershed delineation\'s and attributes at 1:24,000 scale
must be resolved. In the event a drainage unit lies in several
administrative designations, each entity has the responsibility to
delineate the hydrologic boundaries at the scale appropriate to all
interests and to obtain mutual technical approval.

**3. DEFINITIONS**

**3.1 Hydrologic Unit Definitions.**

[Basin.]{.underline} The third level (6-digit) of the hydrologic unit
classification. Basins are nested within or are equivalent to
Sub-regions. Basins were formerly named \"accounting units\".

[Classic Watershed.]{.underline} Land areas having all surface drainage
converging at a single point.

[Composite Watershed.]{.underline} Drainage areas typically formed as
the residual of a larger area after classic watersheds are delineated.
These areas usually do not meet the definition of a classic watershed.

[Contiguous Boundaries.]{.underline} Hydrologic unit boundaries shared
in whole or part by different hydrologic units.

[Hydrologic Unit.]{.underline} A hydrologic unit is an area of land
upstream from a specific point on a stream such as the outlet or mouth
of a stream. The hydrologic unit is defined by a hydrologic boundary
that includes all of the source area that could contribute surface water
runoff directly and indirectly to the designated outlet point. The
hydrologic unit may contain associated surface areas such as related
contributing drainage areas, remnant, non-contributing, and trans-basin
diverted areas to form a landform associated with the certain designated
outlet point.

[Hydrologic Unit Code (HUC).]{.underline} The numerical identifier of a
specific hydrologic unit.

[Non-contributing area.]{.underline} An area within a hydrologic unit
that does not contribute directly to the surface runoff to the river or
stream at the outlet of the hydrologic unit.

[Region.]{.underline} Regions are the largest drainage basins containing
either the drainage area of a major river or the combined drainage areas
of several rivers. Basins are the first level in the hydrologic unit
hierarchy.

[Remnant Areas.]{.underline} These areas are typically formed as
residual areas after delineation of classic watersheds. The most common
example of a remnant area is the small triangular wedge between the
boundaries of adjacent watersheds flowing into the same side of another
stream.

[River Basin.]{.underline} A drainage unit defined by the hydrologic
boundary that feeds a river. This is not a standard hydrologic unit
level designation.

[Sub-basin.]{.underline} Sub-basins divide Basins, and represent part or
all of a surface-drainage basin, a combination of drainage basins, or a
distinct hydrologic feature. The sub-basin is the fourth level of the
hydrologic unit hierarchy. Sub-basins were formerly named \"cataloging
unit\". The sub-basin is coded with eight numerical digits, and the
average size is about 700 sq. miles or 448,000 acres.

[Sub-region.]{.underline} Sub-regions divide the regions and include the
area drained by a river system, and are the second level in the
hydrologic unit hierarchy.

[Sub-watershed.]{.underline} The sixth level in the hydrologic unit
hierarchy. This hydrologic unit is coded with 12 numerical digits
(formerly labeled 14-digits by NRCS). Sub-watersheds generally range in
size from 10,000 to 40,000 acres. In some special areas, a limited
number of sub-watersheds may be smaller than 10,000 acres.

[Watershed.]{.underline} The 5th level of the hydrologic unit
delineation system (formerly labeled 11-digits by NRCS). A watershed is
coded with 10 numerical digits, and range in size from 40,000 to 250,000
acres.

**3.2 Geospatial Definitions.**

[Attribute.]{.underline} A quality or characteristic describing a map
feature. The attributes of hydrologic unit include its code, size, or
name. An attribute is one of two main types of data in a GIS, the other
is geospatial data.

[Contour.]{.underline} An imaginary line on the ground representing the
land surface. All points on the contour lines are of equal elevation.

[Coordinates.]{.underline} Linear and (or) angular quantities
designating the position of a point in relation to a given reference
frame. In a 2-dimensional system, x and y coordinates are used to
designate locations.

[Compilation.]{.underline} Preparation of a new or revised map from
existing maps, field surveys, and other sources.

[Datum]{.underline}. A starting point and reference for a geodetic
survey. Refers to a direction, level, or position from which angles,
heights, depths, speeds and distances are normally measured. Datum as
applied to a horizontal geodetic survey is a reference based on the
shape of the earth. The vertical datum is usually mean sea level.

[Delineation.]{.underline} To outline the boundaries of a hydrologic
unit with a line.

[Digital Elevation Model (DEM).]{.underline} Geo-referenced digital
files consisting of terrain elevations for ground positions at regularly
spaced horizontal intervals, generally 10-30 meters. Stored in a
database and typically used to represent terrain relief.

[Digital Raster Graphic (DRG).]{.underline} A scanned geo-referenced
image of a USGS standard series topographic map. The image inside the
map neatline is georeferenced to the surface of the earth. The
horizontal positional accuracy matches the accuracy of the source map.

[Edge matching.]{.underline} A procedure used to ensure hydrologic unit
boundaries crossing adjoining maps match and connect to create a
continuous or seamless line between maps.

[Coordinate System.]{.underline} Any system where points on the earth\'s
surface are located with reference to a pair of intersecting lines or
grid. The three major coordinate systems used in the U.S. are the
Geographic Coordinate system, State Plane Coordinate system, and
Universal Transverse Mercator Grid system. Each of these coordinate
systems has its unique characteristics and usability.

[Geographic Information System (GIS).]{.underline} A computer system
designed to collect, manage, manipulate, analyze, and display spatially
referenced data. A GIS includes both attribute and geospatial data. The
primary components of a GIS are software, hardware, data and people.

[Geospatial.]{.underline} One of two main types of data in a GIS (the
other being attribute data). Geospatial data represents the shape,
location or appearance of geographic objects. Hydrologic units are
digitized and stored as vector geospatial data.

[Metadata.]{.underline} Data about data, or the description and
documentation of the content, quality, condition, and other
characteristics of geospatial data.

[National Map Accuracy Standards.]{.underline} Specifications governing
the accuracy of topographic and other maps produced by federal agencies.
For example, hydrologic units mapped at 1:24,000 scale, the horizontal
accuracy standard requires the positions of 90 percent of all points
tested must be accurate within 40 feet (12.2 meters).

[Neatline.]{.underline} The lines on a map serving as the outside border
or limits of the map sheet.

[Polygon.]{.underline} A closed loop of x, y coordinate pairs defining
the boundary of an area. A series of straight lines, arcs, or
combinations of both often define the polygon.

[Raster Digitizing.]{.underline} Point, line, and polygon features from
a map are stored as a matrix of cells or pixels of a uniform grid. Map
features are defined by numeric values assigned to the cells.

[Topographic quadrangle.]{.underline} A USGS lithographic printed map
which represents the horizontal and vertical positions of cultural,
political and land features. Map symbols are used to depict mountains,
drainage, roads, county boundaries, etc. usually at scales of 1:100,000
or 1:24,000.

[Topology.]{.underline} The spatial relationships between connecting and
adjacent features. Topology defines the location of geographical
phenomena relative to each other, but is independent of distance or
direction. Topology depicts connectivity of one entity to another.
Topology is required for proper associations to be made among features
such as arcs, nodes, points, and polygons and their attributes.

[Vector data.]{.underline} A coordinate-based data structure used to
represent linear geographic features.

[Vector digitizing.]{.underline} The process of using a digitizer to
encode the locations of geographic features by converting their map
positions to a series of x,y coordinates. Geographic objects are
digitized as a point, line, or polygon. A point is represented by a
single coordinate, a line by a string of coordinates, and an area or
polygon by a series of lines making up the polygon.

**4. CRITERIA TO DELINEATE HYDROLOGIC UNITS**

**4.1 General Criteria.**

This section describes criteria for determining and delineating
hydrologic units at the watershed and sub-watershed levels. The
selection and delineation of watersheds and sub-watersheds requires good
hydrologic judgement, and must be determined solely upon science-based
hydrologic principles to assure a homogeneous national seamless digital
data layer.

The diversity of hydrologic conditions nationwide, and the number of
factors involved in the delineation process preclude an all-inclusive
guideline. Variations will generally be limited to unusual hydrologic or
landform features and dissimilar hydrologic or morphologic drainage area
characteristics. The intent of defining hydrologic units is to establish
a base-line drainage boundary framework having complete accountability
of all land and surface areas, and is hydrologically consistent with
boundaries meeting National Map Accuracy Standards (NMAS) at 1:24,000
scale.

Make the delineation as simple as is practical, and avoid making
hydrologic units favor a particular agency, program, administrative area
or special project. Drainage boundaries generated for special purposes
not meeting these standards will not be certified into the national
watershed boundary database.

> **4.2 Hydrologic Boundaries.**

*Exhibit 1*, *Appendix A* illustrates the six levels of the Hydrologic
Unit hierarchy. Sub-basin boundaries (4th level) generally provide the
starting point for the delineation of watersheds (5th level), and
sub-watershed (6th level) hydrologic units. Sub-basin boundaries may be
changed or adjusted when the existing mapping does not conform to
hydrologic and topographic criteria.

Hydrologic units must be defined along natural hydrologic watershed and
sub-watershed boundaries based on land surface and hydrographic
features. A hydrologic unit has a single flow outlet except in coastal
or lakefront areas. Give priority to delineating watersheds and
sub-watersheds that will be \"classic\" watersheds without subdivided
upstream areas and only one outlet. As the watersheds and sub-watersheds
are subdivisions of the next level of hydrologic unit, they must share
common boundaries with the existing hydrologic units at the next higher
level of the drainage basin.

Some earlier versions of watershed and sub-watershed boundaries used
administrative boundaries to define hydrologic units. Hydrologic unit
boundaries must be determined solely upon hydrologic features. Do not
use administrative or political boundaries such as county, state,
national forest or other similar boundaries as criteria for defining a
hydrologic unit boundary.

Hydrologically based boundary delineation\'s include land area on both
sides of a stream flowing toward a single point. Boundaries should not
follow or run parallel to the center of rivers or streams. Boundaries
will cross the river or stream perpendicularly at the hydrologic unit
outlet. The stream or river may also be crossed at the upstream end of
the hydrologic unit if other same-level hydrologic units are delineated
above the current one.

In the case of a long, narrow hydrologic unit that is typical of a
parallel drainage system, the hydrologic unit boundary may cross the
stream or river just downstream of a significant confluence to divide
the hydrologic unit into suitable sized watersheds or sub-watersheds.
Stream order may be a useful tool for determining the relative
significance of tributaries within an area being subdivided. Delineating
the boundary at a confluence allows for proper nesting of smaller units
within the hydrologic unit for future site-specific planning, assessment
or inventory activities.

In addition to the primary criteria, there are general criteria for the
number of hydrologic units subdivided from a parent unit, the size of
hydrologic units, and the treatment of non-contributing and remnant
areas.

4.3 Number of Subdivided Hydrologic Units.

As a general rule, subdivide each hydrologic unit into 5 to 15 units.
For example, 5 to 15 watersheds (10-digit) will be nested in each
8-digit sub-basin. This approach will accommodate geomorphic or other
relevant basin characteristics. Different areas of the country may be
treated differently, for example, the size of a hydrologic unit in the
Great Plains is not expected to be the same as one in the Northeast.

Occasionally an 8-digit sub-basin hydrologic unit may be smaller than
the national norm. As a result, the number of watersheds or
sub-watersheds nested within the smaller sub-basin would also be
reduced.

4.4 Size of Hydrologic Units.

The hydrologic units of any given level should be about the same size
within a physiographic area. There should not be any hydrologic units
that are orders of magnitude different in size than the rest of the
hydrologic units for a given level.

Nationally, the typical size for a watershed is 40,000 to 250,000 acres.
Use this acreage range as a guide in subdividing 8-digit sub-basins that
are atypically larger or smaller than the national norm. Each watershed
must be completely contained within one 8-digit sub-basin.

The typical size for a sub-watershed is 10,000 to 40,000 acres. Each
sub-watershed must be completely contained or nested within one
watershed.

4.5 Classic Hydrologic Units.

The classic hydrologic unit is a pure hydrologically defined surface
water drainage area*.* Delineate by starting from the designated outlet
(a point on a single stream channel that drains this area), and proceed
to the highest elevation of land dividing the direction of water flow.
This boundary connects back with the designated outlet where it will
cross perpendicular to the stream channel. Boundaries also follow the
middle of the highest ground elevation or halfway between contour lines
of equal elevation.

Determining classic watersheds within size and logical number
constraints will cover much of the area to be subdivided but leaves
\"special situation\" land areas that are addressed in the next section.
These special situation areas typically need to be added in with an
adjacent watershed.

Correctly selecting the outlet point is critical to delineating good
hydrologic units. The best and most obvious hydrologic units are those
defining major tributaries to the larger \"parent\" hydrologic units.
When choosing between small tributaries for hydrologic unit definition,
higher order streams will typically be chosen. The downstream end of the
hydrologic unit will be the confluence with the main stem of the
higher-level hydrologic unit, or the main stem of a same level
hydrologic unit if possible. Hydrologic units defined with an outlet
other than along the main stem of the \"parent\" hydrologic unit often
create remnant hydrologic unit areas around the main stem.

A situation where this definition may not be realistic is where the
drainage area is exceptionally elongated and without tributaries, and
size criteria dictates dividing of the unit. The boundaries should be as
simple as possible, allowing full accountability of area and water
yield. Hydrologic units may be divided at a lake outlet if the upstream
drainage area size is appropriate for the hydrologic unit level being
delineated. A dam, diversion, or stream confluence may be used to divide
a watershed into upper and lower parts.

4.6 Remnant Areas.

The delineation of hydrologic units may result in remnant areas around
the main stem of larger streams, even when good hydrologic judgement and
other factors described above are used. These remnant areas also have
been referred to as \"related contributing drainage areas\" or
\"composite watersheds\". Remnant areas typically occur as wedge shaped
areas along inter-fluvial regions between adjacent watersheds, or as
over-bank areas along a stream between junctions with tributaries*.*

Remnant areas also occur in coastal outlet areas to several mainland or
island watersheds that are individually smaller than defined for a given
hydrologic unit level. Another example of a remnant area is when a
number of streams that outlet into the ocean are grouped into a single
hydrologic unit. A remnant area may occur when one or more islands are
included into a single hydrologic unit. If the size of adjacent remnant
areas is in the size range of the hydrologic unit level being defined,
they should be combined into a single hydrologic unit. If the areas are
relatively small, they should be included within a larger, adjacent
hydrologic unit.

4.7 Non-contributing Areas.

Drainage areas that do not flow toward the outlet of any hydrologic unit
are considered non-contributing areas. Such areas may be due to
glaciated plains (potholes), enclosed basins, karst topography, playas,
cirques, depression lakes, dry lake beds, or similar land forms. Such
areas may be large enough to be designated as either a watershed or
sub-watershed. The largest non-contributing area in the U.S. is the area
of the Great Basin in Utah. This closed area is large enough to be
considered as a sub-region hydrologic unit.

If non-contributing areas are relatively small and dispersed, or if they
are scattered throughout a drainage area, they should be considered as
part of the delineated hydrologic unit. Note the size of the
non-contributing area in the attribute file for the hydrologic unit
containing the non-contributing area.

If a non-contributing area is on the boundary between two or more
hydrologic units, determine the low point along the non-contributing
area boundary. The hydrologic unit adjacent to the low point on the
boundary should be associated with this non-contributing area.
Occasionally, a non-contributing area may be drained (via canal or
pipeline), thus becoming part of a surrounding or adjacent hydrologic
unit. Local investigation in cases of suspected drainage or diversion
may be needed.

Document the criteria used to delineate non-contributing areas in the
metadata file if a significant number of non-contributing areas are
defined. Include the amount of non-contributing areas within a
hydrologic unit as an attribute of the database. Delineate
non-contributing areas in a consistent manner throughout the state.

4.8 Reservoirs and Natural Lakes.

The delineation of hydrologic unit boundaries is often complicated by
the presence of reservoirs or large natural lakes. The delineation of
hydrologic units should be based on the natural flow of water due to the
topography of the land, except where long-term permanent large-scale
water bodies such as lakes and reservoirs exist.

Since reservoir pool levels can fluctuate significantly, hydrologic
units should be mapped through reservoirs based on legacy channels.
Boundaries should not be delineated to the reservoir\'s normal, average,
or high pool levels. In essence, ignore the reservoir pool when
delineating boundaries. If maps of legacy channels do not exist,
automated tools may be used to identify reservoir hypsography from
digital elevation models.

For a natural lake that is of a size consistent with the hydrologic unit
level being delineated, it is appropriate to delineate the lake as a
separate hydrologic unit. In general, tributary areas that flow directly
into the lake would be encompassed in the \"lake hydrologic unit\"*.*
Tributary areas flowing directly into a lake, and are of a size
consistent with the hydrologic unit level being delineated, would be
delineated as \"classic\" watersheds with a pour point at the lake
margin.

Areas draining into a lake, but which cannot be delineated at a
consistent size should be included as part of the lake hydrologic unit
unless the result of the combined unit exceeds the consistent size of
other units in that level. In this circumstance, the lake would be
delineated as a hydrologic unit and the adjacent slope areas would be
delineated as composite hydrologic units*.* These composite hydrologic
units should be subdivided, when necessary, based on hydrography and
maintaining consistent size.

**4.9 Diverted Waters.**

Delineate hydrologic units based on natural topographic features and
surface water flow. Avoid using ditches and canals to decide natural
surface-water drainage areas. It is important to track diversions that
move water from one hydrologic unit to another.

When all or part of the flow from one hydrologic unit is continuously
discharged into another by constructed trans-basin diversions, document
the diverted flow as attributes to both the water-losing and
water-gaining hydrologic units. This unique drainage area should be
delineated separately, and associated with the receiving hydrologic unit
for accountability of total drainage area included in both attribute
tables. Include the date of the diversion, flow rates, and water rights
as attribute information if available in the metadata remark\'s field
for both the receiving and losing hydrologic units. When the flow is
only partially or intermittently diverted, the hydrologic unit need not
be adjusted but an adequate attribute entry should be made of the
diversion.

Do not adjust the location of hydrologic units due to interconnected
flow from one hydrologic unit to another during high flow stages in
rivers or streams. Ditches significantly altering flow may be treated as
a stream, however make every attempt to base hydrologic units on natural
surface water flow.

**4.10 Coastal Areas.**

*Due to the unique qualities of the nation\'s coastlines, specialized
guidelines are presently being developed for these areas, and will be
incorporated into these standards when finalized.* The coastal
guidelines will apply to non-ocean coastal areas such as the Great Lakes
and some portions of the Mississippi River, however the coastal
guidelines will not apply to inland flatlands.

**5. MAPPING AND DELINEATION PROCESS**

The mapping process used to delineate watershed and sub-watershed
boundaries has typically been done using either manual or semi-automated
techniques. More fully automated techniques are being evaluated for use
in streamlining and improving the delineation of hydrologic unit
boundaries. This section briefly describes the source maps and data
needed for delineation, and the manual, semi and more fully automated
delineation processes. Either process described is acceptable providing
the final hydrologic units meet the standards.

**5.1 Base Maps, Map Scale and Map Accuracy.**

The official base map for delineating watershed and sub-watershed
boundaries is the USGS 1:24,000 scale topographic quadrangles. The
delineation may be done using either a copy of the printed map, Digital
Raster Graphic of the 1:24,000 scale topographic map, or the 7.5 minute
Digital Elevation Model (DEM). In Alaska and the Caribbean, USGS base
maps at 1:25,000 or 1:63,360 scale may be used in the absence of
1:24,000 scale base maps.

Hydrologic unit boundaries must be delineated to meet National Map
Accuracy Standards (NMAS) at the 1:24,000 scale, and geo-referenced to
the standard USGS 1:24,000 topographic quadrangles. Adherence to these
accuracy, scale and map format standards will produce a seamless and
consistent national hydrologic unit geographic coverage that:

 is in a format acceptable to the majority of data users,

 allows for efficient geospatial and attribute data exchange between
agencies,

 supports multi-agency planning programs, models, database and GIS
analyses,

 is consistent with the format and scale of most agency geospatial
databases,

 registers with digital orthoimagery and other similar geospatial
databases.

**5.2 Source Maps.**

**5.2.1 Base Maps.**

Use the printed copies of the USGS topographic quadrangle maps. Most 7.5
minute topographic maps are published at 1:24,000 (1\" = 2,000\'), but
some are printed at 1:25,000 scale (1\"= 2083\') or 1:20,000
(1\"=1667\'). Do not use \"bluelines\" or similar copies. USGS state
base maps at 1:500,000 scale and the USGS 1:100,000 scale topographic
series maps can be used for preliminary mapping of hydrologic unit
boundaries.

**5.2.2 Hydrologic Unit Maps.**

Obtain a printed copy of the USGS 8-digit state hydrologic unit map, and
hydrologic unit maps prepared by NRCS, Forest Service, and state
agencies. The USGS 8-digit state hydrologic unit maps done at the fourth
level of detail provide the appropriate reference to begin delineating
the fifth and sixth level hydrologic units.

Use these maps to determine the general location of the new or redefined
watershed or sub-watershed hydrologic units, review the existing coding
system, and determine the level of mapping complexity needed. 

**5.2.3 Reference Maps.**

The following reference maps may be helpful in delineating hydrologic
boundaries:

>  county drainage including diversions and ditches,\
>  direction of flow drainage,\
>  storm sewer map,\
>  land cover map,\
>  soil surveys,\
>  orthophotos or aerial photographs,\
>  major land resource area map,\
>  watershed project maps.

Retain as a permanent record all maps, measurement data, and other
source materials used to determine the location of hydrologic units.

> **5.2.4 Digital Data.**

Digital geospatial data, such as the USGS 1:24,000 scale Digital Raster
Graphics (DRGs) can be used for on-screen digitizing of hydrologic
units, and for clarifying line position when using other digitizing
methods. Digital Elevation Models (DEMs) are needed if an automated
method is used to delineate and/or digitize the hydrologic unit
boundaries. The Environmental Protection Agency (EPA) river reach files,
and the National Elevation and Hydrography Datasets are other useful
databases for identifying primary tributaries within an area being
subdivided.

> **5.3 Map Delineation Process.**

The hydrologic unit mapping process can be done using either manual or
automated methods. Within each of the two methods, there are slightly
different procedures for completing the delineation, mapping, and
digitizing. Use of either process is acceptable providing the final
geospatial database is meets the NMAS, and the criteria for delineating
hydrologic units described in Section 4.

Drainage divides are usually determined by bisecting ridges, saddles,
and contour lines of equal elevation. Hydrologic unit boundaries follow
the middle of the highest ground elevation or halfway between contour
lines of equal elevation. The hydrologic unit boundary will cross
perpendicular to the stream channel at the outlet. The hydrologic unit
boundary has only one outlet point, except in the case of remnant areas.
Hydrologic unit boundaries cannot be streams or rivers.

Use the topographic map detail (contours, elevations, drainage patterns)
to interpret and delineate the hydrologic units. In areas of flat
terrain, interpolation between contours may be done by reference to
trails, old roads, or firebreaks in forested areas; all of which
frequently follow drainage divides. More detailed information may be
obtained from local highway or street profiles, examination of aerial
photographs, county drainage or ditch maps, and ground reconnaissance by
local employees.

Some state hydrologic unit maps of 8 and 10-digit boundaries were either
done at different map scales or on inaccurate base maps. These maps are
not acceptable for digitizing, but are good to use as a general
reference in relocating the 10-digit hydrologic units onto the accurate
1:24,000 topographic maps.

Classic hydrologic unit boundaries must edge-match at state boundaries.
States or regions should consider delineating hydrologic units within an
8-digit sub-basin at the same time, and not stop at state boundaries. If
this is not possible, adjoining states need to coordinate the
delineation of hydrologic unit boundaries at state boundaries.

5.4 Manual Method.

Begin by mapping the sub-basin (8-digit) and watershed (10-digit)
boundaries onto the USGS 1:100,000 scale topographic maps. Completing
this process provides a good overview of where the sub-basin and
watersheds are located, illustrates the level of detail, and shows which
1:24,000 topographic maps need to be mapped. If the locations of any
8-digit boundaries are questionable or need to be re-located to be more
hydrologically correct, notify the state\'s USGS District office before
making the adjustment or revision.

Compile the sub-basin and watershed boundaries from the 1:100,000
topographic maps onto the USGS 1:24,000 topographic maps. Locate the
boundaries on the 1:100,000 map, and visually delineate boundaries onto
the 1:24,000 scale topographic maps. When transferring the boundaries,
refine and adjust the boundary location to fit the more detailed contour
intervals, and drainage patterns on the 1:24,000 topographic maps. After
the 8 and 10-digit hydrologic units are delineated, add the 12-digit
sub-watersheds to the map, and code the hydrologic units. Sub-basin
(8-digit) and watershed (10-digit) boundaries previously mapped on
smaller-scale state and national base maps cannot be merely transferred
to the larger scale topographic maps for this task.

**5.5 Automated Methods.**

Improvements in GIS software and availability of geospatial data offer
other alternatives for hydrologic unit development. Two different
automated methods are summarized below:

> **5.5.1 On-Screen Mapping and Digitizing.**

Delineate and digitize \"DRAFT\" 10-digit watersheds at 1:100,000 scale
on mylar sheets registered to paper topographic maps. After the
watershed delineation is completed, the next step is to develop the
sub-watershed coverage by sub-basin, and refine the 8 and 10-digit
boundaries to meet NMAS at the 1:24,000 scale. To accomplish this,
develop a reference plot for each 8-digit sub-basin showing DEM derived
contour data, streams, 7.5 minute topographic quad boundaries, quad
names, and 10-digit boundaries and codes. Plot a second worksheet for
each 10-digit watershed within the sub-basin showing contours, streams,
10-digit boundaries and codes. Sketch 12-digit boundaries with
sub-watershed codes on the individual 10-digit worksheets. Use the
worksheet as a visual reference for on-screen delineation and digitizing
onto the 1:24,000 scale DRGs.

Do not use existing digital hydrologic unit databases developed from
smaller scale state or national base maps with the 1:24,000 scale
topographic maps. Overlaying or digitally combining digital data
developed from small-scale maps onto larger scale maps will result in
differences in line location of the same features. The boundary
locations must be re-mapped and digitized to conform to the more
accurate and detailed topographic maps.

**5.5.2 Hydrologic Modeling from Digital Elevations.**

GIS, image processing and hydrologic modeling applications make use of
DEMs to represent landform features and drainage network patterns. DEMs
are available in different horizontal and vertical resolutions. Digital
elevation data equivalent or better to the vertical and horizontal
resolutions of the either the 30 meter, Level 2 DEMs or National
Elevation Dataset (NED) can be used to develop a \"draft or
preliminary\" delineation of hydrologic units. DEMs or NED are combined
with other geospatial data such as EPA river reach files and hydrography
in a GIS to simulate drainage networks, stream courses and
direction-of-flow by applying hydrologic models. Maps generated from
digital hydrography data with flow direction arrows are also helpful in
delineating hydrologic units.

Depending upon the modeling techniques, data resolution, data
consistency, software applications, and other characteristics; the DEMs
and NED will most likely provide a generalized depiction of landforms
especially in areas of moderate topographic variations or flat areas.
For this reason, all DEM and NED established boundaries need to be
independently checked on 1:24,000 DRGs, and reviewed closely. A detailed
description of the source elevation model must be documented in the
metadata.

**5.6 Updating and Revising Hydrologic Units.**

Coordinate the revision of hydrologic units with other cooperating
agencies. When hydrologic unit boundaries are revised, update the area
measurements, and note any significant revisions as \"revised\" when the
new data is released. Record the revision date in the attribute file for
each hydrologic unit whose boundaries or codes were revised. Notify the
USGS, Water Resources Division of any proposed changes when 8-digit
boundaries are revised. All updated geospatial files need to be archived
at your agency\'s geospatial archival center or geospatial
clearinghouse.

**6. CODING AND NAMING**

**6.1 Hydrologic Unit Levels.**

The six different levels of hydrologic units are shown below, and in
*Appendix A, Exhibit 1.*

+-----------+------------+--------+------------------+---------------+
| **Hyd     | **Name**   | **Co   | **Size**         | **Units**     |
| rologic** |            | ding** |                  |               |
|           |            |        |                  |               |
| **Unit**  |            | **Di   |                  |               |
|           |            | gits** |                  |               |
| **Level** |            |        |                  |               |
+-----------+------------+--------+------------------+---------------+
| 1         | Region     | 2      |                  | 21            |
+-----------+------------+--------+------------------+---------------+
| 2         | Sub-region | 4      |                  | 222           |
+-----------+------------+--------+------------------+---------------+
| 3         | Basin      | 6      |                  | 352           |
+-----------+------------+--------+------------------+---------------+
| 4         | Sub-basin  | 8      | 250,000-450,000  | 2,149         |
|           |            |        | Acres            |               |
+-----------+------------+--------+------------------+---------------+
| 5         | Watershed  | 10     | 40,000-250,000   | 22,000        |
|           |            |        | Acres            | (estimate)    |
+-----------+------------+--------+------------------+---------------+
| 6         | Sub        | 12     | 10,000-40,000    | 160,000       |
|           | -watershed |        | Acres            | (estimate)    |
+-----------+------------+--------+------------------+---------------+

**6.2 Coding Watersheds and Sub-watersheds.**

Do not change the numbering of the 8-digit sub-basin codes as they were
officially established by the ACWI in the 1970\'s. Assign a new unique
numbered code to each watershed and sub-watershed. Maintain the 2-digit
field length for successive 5th and 6th-level watersheds and
sub-watersheds to be consistent with the coding pattern established in
the 1970\'s by interagency water data committees. Coordinate the coding
within a sub-basin across state boundaries.

Do not complicate the coding of hydrologic units by trying to code
hydrologic units as to their complete or partial presence within a
county or presence within two or more counties or states. The approach
is to number the hydrologic units sequentially beginning upstream and
proceeding downstream. For example, starting at the uppermost end of the
drainage, code the first watershed as 9908020301, with the next
watershed downstream coded as 9908020302.

Sample numbering of hydrologic units: [Level]{.underline}

First 2 fields are the Region 01 1

Next 2 fields are the Sub-region 0108 2

Next 2 fields are the Basin 010802 3

Next 2 fields are the Sub-basin 01080204 4

Next 2 fields are the Watershed 0108020401 5

Next 2 fields are the Sub-watershed 010802040101 6

**6.3 Hydrologic Unit Naming Protocol.**

Use the following guidelines when assigning a name to a hydrologic unit
polygon:

1\. Assign each hydrologic unit with a unique name relating to a major
hydrologic feature within the hydrologic unit.

2\. If primary water features in different hydrologic units have the
same name, use the primary water feature for each hydrologic unit
modified by appending the name of the receiving water body. For example,
Drift Creek-Siletz River, or Drift Creek-McKenzie River.

3\. It is appropriate to use streams, lakes, and reservoirs as major
hydrologic features for naming. Preference should be given to streams
unless the polygon contains a dominant lake or reservoir. Example:
Harney Lake / Malheur Lake.

4\. Use mainstem stream names at the outlet of the hydrologic unit
whenever possible.

5\. End each hydrologic unit name with one of the following words
spelled out in entirety: \"River\", \"Creek\", \"Branch\", \"Fork\",
\"Slough\", \"Lake\", \"Bay\", \"Frontal\", \"Reservoir\", \"Inlet\",
\"Channel\", \"Harbor\", \"Cove\", \"Headwaters\", \"Sea\", \"Ocean\",
\"Bayou\", \"Estuary\", \"Upper\", \"Middle\", and \"Lower\".

6\. Avoid abbreviations, e.g., N. Fk., R., Res., etc.

7\. When a major river is subdivided into multiple hydrologic units
along the mainstem length, the preferred naming convention is \"Upper\",
\"Middle\", or \"Lower\".

8\. If a mainstem river is subdivided into more than three hydrologic
units, do not use the \"Upper\", \"Middle\" and \"Lower\" naming
convention. Use the standard naming protocol. If the name includes the
name of a primary tributary or primary hydrologic feature, separate the
names with a \"dash\" character; e.g., Upper Willamette River-Deep
Creek.

9\. Use of the word \"of\" is appropriate to shorten the naming
convention of tributaries sharing the same name of the mainstem river,
e.g., North Fork of the Willamette River, Upper North Fork of the Coast
Fork of the Willamette River.

10\. Use of the term \"Frontal\" is reserved for areas that include
multiple, non-convergent rivers. The sequence for naming areas in the
Frontal should follow from north to south; e.g., Netarts Bay/Sand
Lake/Neskowin Creek Frontal.

**6.4 Coding at International Borders.**

Code watersheds and sub-watersheds by beginning the coding in the upper
most areas according to the criteria in Section 6.2.

**7. GEOSPATIAL DATA STRUCTURE**

**7.1 Digitizing.**

The vector data structure is the required method for the hydrologic unit
geospatial database. The line segments and hydrologic unit codes for
each dataset must be topologically structured. Hydrologic unit
boundaries are digitized as closed area polygons.

**7.2 File Format.**

The file format criteria shown below is required for final certification
of the hydrologic units, and to merge individual state coverage\'s into
a seamless national database. The hydrologic unit data files are to be
provided for certification in an ArcInfo coverage or ArcView shapefile.
These standards do not cover file formats for data distribution. Formats
for distributing data are the responsibility of the data provider and
data user.

> **7.2.1 File Names.**

The coverage naming convention is: 2-digit state abbreviation_hu12_utm83

Arc coverage example: oh_hu12_utm83

ArcView file example: oh_hu12_utm83.shp

> **7.2.2 Projection of Coverage.**

Use the projection system described below. Provide ArcInfo coverages as
double precision. For ArcView shapefiles, provide a readme file with the
projection information.

![](media/image1.png){width="4.602083333333334in"
height="1.0916666666666666in"}

> **7.2.3 Exporting and Compression.**

Use Arc "export" command to produce a coverage with an \".e00\"
extension. Use compression software that is suitable for UNIX and NT
environments.

Examples:

1.  Export as oh_hu12_utm83 to oh_hu12_utm83.e00, copy into a new
    directory along with the metadata, then zip these files into a
    single file having a .zip file extension.

2.  Copy the metadata and ArcView shapefiles (.shp, .dbf, .sbx, .sbn,
    .shx) to a new directory, then zip these files into a single file
    having a .zip file extension.

> **7.2.4 FTP Posting and Mailing.**

Post the database to an ftp site, and notify the agency contact having
responsibility for data certification and archival. The coverage may
also be written to a CDROM for archival delivery and final
certification.

**7.3 Attribute Table Structure.**

Spell the attribute field names exactly as shown below for the polygons
and linework files. Calculate the acres to the nearest one-tenth acre
from the \"Area\" field, e.g. 5,386.4. The \"States\" field needs to
include the names of all states within a sub-watershed. Use the 2-digit
postal abbreviation, and sort the states in alphabetical order with a
hyphen separating each state, e.g. KS-MO-OK.

> **7.3.1 Polygons (.pat) Attribute Scheme**

[Item Name]{.underline} [Int. Width]{.underline} [Type]{.underline}
[Contents]{.underline}

HUC-8 8 C

HUC-10 10 C

HUC-12 12 C

ACRES 4 B calculate from \"Area\"

STATES 12 C AR-MO-KS

NCONTRIB_DA 4 B non-contributing acres

DS_HUC 12 C downstream same level HUC

NAME 80 C name of hydrologic unit

FLAGS 80 C canal, ditch, control structure

**7.3.2 Line Work (.aat) Attibute Scheme**

[Item Name]{.underline} [Int. Width]{.underline} [Type]{.underline}
[Contents]{.underline}

HUC LEVEL 1 I highest level of HUC associated

LINESOURCE 20 C 24KDIGITIZED, 24KDRG, 24KDEM, etc2,

METADATA_ID 1 I record sequence number

**8. QUALITY ASSURANCE AND QUALITY CONTROL**

**8.1 Quality Control.**

Ideally, hydrologic units are delineated using an interagency process,
however it may be necessary for one agency to take the lead in
developing and certifying the hydrologic unit boundaries. Hydrologic
unit boundaries should be reviewed at the originating agency by a
hydrologist, natural resource specialist, or GIS Specialist with
background and experience with hydrologic units. The originating agency
should invite representatives of the Interagency Hydrologic Unit Group,
and or local groups to participate in the development and review of
delineation\'s before the data is submitted for agency certification and
release to the public. The database should go through an extensive
review process by the state representatives before submitting for
certification.

Conduct reviews and editing checks throughout the delineation process.
At a minimum, make edits after the watersheds and sub-watersheds are
delineated, mapped, and digitized. See the editing checklist sample
shown in Appendix C for documenting the review.

**8.2 Editing Checklist.**

Below is a recommended list of items to be checked during the
delineation and digitizing process. This is not an inclusive list, but
covers most items to be verified.

 Agencies should work directly with their adjoining state counterparts
to assure the hydrologic unit boundaries are edge-matched at state
boundaries. This is necessary for maintaining a consistent national
database of hydrologic units. Resolve differences in hydrologic unit
delineations at state boundaries before the data is certified for
distribution to the public.

 Hydrologic units that were difficult to delineate in areas such as
flat terrain may need to be field checked. Make notes on a checklist
about how certain boundaries were established.

 Use local sources to resolve the location of questionable boundaries.
Make notes where local knowledge supersedes source maps.

 Check the coding system for correctness, duplication or missing codes.
Coding of hydrologic units must be consistent within a sub-basin
covering more than one state. Each polygon must have a label.

 Check the attribute table making sure the fields are completed
correctly with no empty fields.

 Make sure the \"Acreage\" field is calculated from the \"Area\" field,
and recorded to 0.1 acre.

 Verify the \"State\" field is labeled correctly with the 2-digit
postal abbreviation, hyphen between multiple states, and is in
alphabetical order.

 Are 5-15 hydrologic units nested within each level?

 Are hydrologic units consistently delineated across the state?

 Check the acreage of 10-digit watersheds confirming they are within
the recommended range (40,000-250,000 acres). Check acreage of 12-digit
sub-watersheds to see if are within recommended range (10,000-40,000
acres with none below 3,000).

 Does the coding of hydrologic units within a given level meet the
guidelines for starting upstream and progressing downstream.

 Check and note in the attribute data any exceptions such as
non-contributing and trans-basin flow areas within a hydrologic unit
boundary.

 Verify the coverage is projected to UTM, NAD83, GRS1980, meters,
correct zone, and double precision. If not, re-project according to
guidelines.

 Do the hydrologic unit delineation\'s meet NMAS for 1:24,000?

**8.3 Geospatial Data Certification.**

Agencies involved in the development of the watershed and sub-watershed
geospatial database should establish organizational responsibility
certifying the data before releasing the data to the public or other
agencies. After the 6th level hydrologic units are completed, the
originating office will submit the data for final review and
certification. Any supporting material such as text documents describing
the procedure used to delineate and digitize the watersheds and
sub-watersheds, a summary of findings for the watersheds and
sub-watersheds, and explanatory hard copy maps would be beneficial for
use in the final certification review.

The final certification will check for:

 adherence to the interagency guidelines,

 mapping and delineation accuracy and consistency,

 coordination and matching of boundaries and codes across state
boundaries,

 node and label error detection,

 verification of the format and required fields listed in the attribute
table,

 proper completion of metadata to FGDC standards.

**9. METADATA**

According to an Executive order signed by the President on April 11,
1994, all federal agencies developing geospatial data are required to
document newly created data by completing metadata. The FGDC content
standards for metadata is required. A sample of a completed FGDC
compliant metadata template for hydrologic units is shown in the Exhibit
section.*.*

**10. APPENDICES**

**Appendix A: Illustrations.**

**Exhibit 1. Hydrologic Unit Hierarchy.**

![](media/image2.jpeg){width="5.997222222222222in"
height="6.893055555555556in"}

![](media/image3.png){width="5.9944444444444445in"
height="7.344444444444444in"}

**Exhibit 2.** Sample delineation of a major lake as a separate 5th
level hydrologic unit.

![](media/image4.png){width="5.996527777777778in"
height="4.245833333333334in"}

**Exhibit 3.** Sample of a non-contributing watershed within a
sub-basin.

![](media/image5.png){width="4.813194444444444in"
height="4.932638888888889in"}

**Exhibit 4.** Sample of classic watershed.

![](media/image6.png){width="3.7527777777777778in"
height="3.352777777777778in"}

**Exhibit 5.** Sample of watershed delineation\'s within a sub-basin
with a major reservoir.

![](media/image7.jpeg){width="5.992361111111111in"
height="4.220138888888889in"}

**Exhibit 6.** Sub-watershed boundary shown in red is delineated
correctly along ridgeline. It meets NMAS for 1:24,000 scale maps.

![](media/image8.jpeg){width="5.992361111111111in"
height="4.220138888888889in"}

**Exhibit 7.** Subwatershed boundaries are shown in red. Outlets located
correctly at confluence, boundary cross perpendicular to river.

![](media/image9.jpeg){width="5.992361111111111in"
height="4.220138888888889in"}

**Exhibit 8.** Subwatersheds (colored areas) delineated incorrectly
along the river. The boundaries should cross the river or have outlets
at tributaries.

**Appendix B: Acronyms**

ACWI Advisory Committee on Water Information

BLM Bureau of Land Management

DEM Digital Elevation Model

DRG Digital Raster Graphic

EPA Environmental Protection Agency

FGDC Federal Geographic Data Committee

FTP File Transfer Protocol

GIS Geographic Information System

HUC Hydrologic Unit Code

NMAS National Map Accuracy Standards

NRCS Natural Resources Conservation Service

USFS U.S. Forest Service

USGS U.S. Geological Survey

UTM Universal Transverse Mercator

#### 

#### 

**Appendix C: Tables**

**Figure 1. Sample Edit and Quality Control Checklist.**

  ----------------------- ------------------------- ---------------------
  SUB-BASIN NUMBER:                                 
  17010208 SUB-BASIN                                
  NAME: FLATHEAD LAKE                               

                          **Name**                  **Date**

  Base Map Plot           Lou Bayou                 11-01-98

  Draft Linework          Sandy Lake                11-15-98

  Digitizing              Sandy Lake                12-31-98

  Field Review                                      

  Edits                   Ray Bay                   7-9-99

  State Office Check                                

  Final Certification                               

                                                    
  ----------------------- ------------------------- ---------------------

Figure 2. Sample Supplemental Process Notes.

*Boundary Notes:*

 Field Review Note: Surface waters in sub-watershed 170102080140 appear
to be completely diverted into the Columbia Falls city water supply.
Confirmed this boundary by showing the return flow outlet location on
Flathead River to include confluence.

 Field Review Note: Based on 1:24,000 topographic quad data, none of
the 12-digit units were classified as sub-watershed type
\"non-contributing\". Field review included a careful check of units
170102080160 and 80 for possible non-contributing inclusions. Outlined
all non-contributing areas greater than 1,000 acres in size.

 Watershed boundaries and coding significantly revised in Flathead Lake
area from that shown in draft 10-digit watershed coverage. Flathead Lake
covers an area of 125,415 acres, therefore stands alone as a 10-digit
watershed.

 Pour point for Flathead Lake sub-basin is based on RF3 data and occurs
at Kerr Dam, slightly downstream of the natural lake outlet.

*Data Exceptions:* Possible diverted flow in 170102080140. No
significant non-contributing areas.

*Watershed and Sub-watershed Codes:* See attached attribute table.

*Attribute List:* See attached attribute table.

*1:24,000 DRG or Reference Topographic Quad List:* See attached quad
list.

*Archived Items (State Office):* Paper contour plots and index base map.
Shapefile-mtsogis:/data4/av.chad/utm11/170102/08/dr208

*Field Review Comments:*

*Edit Comments:*

*State Office Review Comments:*

*Final Certification Comments:*

Figure 3. Sample Hydrologic Unit Boundary Metadata Template

Identification_Information:

Citation:

Citation_Information:

Originator:

U. S. Department of Agriculture,

Natural Resources Conservation Service

Publication_Date: \_\_\_\_\_\_\_(1)\_\_\_\_\_\_\_\_

Title:\_\_\_\_\_\_\_\_\_\_\_\_\_(2)\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Geospatial_Data_Presentation_Form: vector digital data

Publication_Information:

Publication_Place: Fort Worth, Texas

Publisher:

U. S. Department of Agriculture,

Natural Resources Conservation Service

Online_Linkage: http://www.ftw.nrcs.usda.gov/HUC/huc_download.html

**Description:**

**Abstract.** This geospatial dataset is a hydrologic unit boundary
layer that is at the Sub-watershed (12-digit) level. The dataset was
developed by delineating the boundary lines on 1:24,000 base maps and
digitizing the delineated lines. Digital Elevation Model data may have
been used in part of the process to establish preliminary boundaries.

This data set consists of geo-referenced digital map data and associated
attribute. The hydrologic unit code attached to each delineated polygon
is linked to the attribute data, which can contain information on
non-contributing area and trans-basin flow.

**Purpose:**

The watershed and sub-watershed hydrologic unit boundaries provide a
uniquely identified and uniform method of subdividing large drainage
areas. These smaller sized hydrologic units (up to 250,000 acres) are
useful in many programs supported by the NRCS and others.

This data set is intended as a tool for water-resource management and
planning activities, particularly for site-specific and localized
studies, which require the amount of detail provided by a large-scale
map.

**Supplemental_Information:**

The following procedures were used to produce this data set:

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_Free
Text\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: \_\_\_\_\_\_(3)\_\_\_\_\_\_\_\_\_\_

Currentness_Reference: Publication date

Status:

Progress: Complete

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: \_\_\_\_\_\_\_(4)\_\_\_\_\_\_\_\_\_\_

East_Bounding_Coordinate: \_\_\_\_\_\_\_(5)\_\_\_\_\_\_\_\_\_\_\_\_

North_Bounding_Coordinate: \_\_\_\_\_\_(6)\_\_\_\_\_\_\_\_\_\_\_\_

South_Bounding_Coordinate: \_\_\_\_\_\_(7)\_\_\_\_\_\_\_\_\_\_\_\_

**Keywords:**

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: Hydrologic units

Theme_Keyword: Watershed Boundaries

Theme_Keyword: Sub-watershed Boundaries

Place:

Place_Keyword_Thesaurus: Counties and County Equivalents of the

United States and the District of Columbia (FIPS Pub 6-3)

Place_Keyword: \_\_\_\_\_\_\_\_(8)\_\_\_\_\_\_\_\_\_\_

Place_Keyword: \_\_\_\_\_\_\_\_(9)\_\_\_\_\_\_\_\_\_\_

**Constraints:**

Access_Constraints: None

Use_Constraints:

The U.S. Department of Agriculture, Natural Resources Conservation
Service, should be acknowledged as the data source in products derived
from these data. These data should not be used at scales greater than
1:24,000.

This is public information and may be interpreted by organizations,
agencies, units of government, or others based on needs; however they
are responsible for the appropriate application of the data. Federal,
state, or local regulatory bodies are not to reassign to the Natural
Resources Conservation Service any authority for the decisions they
make. The Natural Resources Conservation Service will not perform any
evaluations of these maps or purposes related solely to State or local
regulatory programs. Photographic or digital enlargement of these maps
to scales greater than that at which they were originally delineated can
cause misrepresentation of the data. If enlarged, the maps will not
include the fine detail that would be appropriate for mapping at the
small scale. Digital data files are periodically updated. Files are
dated, and users are responsible for obtaining the latest version of the
data.

**Contacts:**

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

U.S. Department of Agriculture, Natural Resources Conservation Service

Contact_Position: Staff, Geospatial Databases Branch

Contact_Address:

Address_Type: Mailing address

Address: 501 W. Felix St., Bldg. 23, P.O. Box 6567, City: Fort Worth,
State_or_Province: Texas

Postal_Code: 76115, Country: USA

Contact_Voice_Telephone: (800)-672-5559

Contact_Facsimile_Telephone: (817) 509-3469

Contact_Electronic_Mail_Address: nrcs_data@ftw.nrcs.usda.gov

Native_Data_Set_Environment: Windows_NT, 4.0, Intel ARC/INFO version
7.1.2

Cross_Reference:

Citation_Information:

Originator: U.S. Department of Agriculture, Natural Resource
Conservation Service

Publication_Date: \_\_\_\_\_\_(10)\_\_\_\_\_\_\_\_\_\_\_

Title: \_\_\_\_\_\_\_(11)\_\_\_\_\_\_\_\_\_\_\_

Geospatial_Data_Presentation_Form: table, map

**Data_Quality_Information:**

Attribute_Accuracy:

Attribute_Accuracy_Report:

Polygon identifiers are manually checked with the original base map
using the attribute file. Verification on polygon identification
continuity on each side of a neatline is done visually on the screen as
adjacent quad representations are

assembled into larger area data layers.

Logical_Consistency_Report: Certain node/geometry and topology (GT)
polygon/chain relationships are collected or generated to satisfy
topological requirements. (The GT-polygon corresponds to a hydrologic
unit or a portion of a hydrologic unit at the edge of a quadrangle
sheet.) Some of these requirements include: chains must begin and end at
nodes, left and right GT-polygons are defined for each chain element and
are consistent throughout, and the chains representing the limits of the
file (neatline) are free of gaps. The tests of logical consistency are
performed using vendor software. The neatline is generated by connecting
the explicitly entered four corners of the digital file. All data
outside the enclosed region are ignored and all data crossing
geographically straight lines are clipped at the neatline. Neatline
straightening aligns the digitized edges of the digital data with the
generated neatline (i.e., with the longitude/latitude lines in
geographic coordinates). All internal polygons are tested for closure
with vendor software and are checked on hard copy plots. All data are
checked for common boundary lines (i.e., adjacent polygons with the same
label). Quadrangles are edge matched within the Sub-basin area and edge
locations generally do not deviate from centerline more than 0.01
inches.

Completeness_Report:

**Positional_Accuracy:**

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report: Horizontal Positional Accuracy
Report: The accuracy of these maps is generally based on the contour
information or DEM data available for the base maps. Such data may be
supplemented with site visits to locate ridge lines for hydrologic unit
boundaries in flat terrain areas, changes in drainage patterns due to
man\'s activities. The differences in positional accuracy between the
hydrologic unit boundaries and their digitized map locations is unknown.

Hydrologic unit boundaries generally were digitized within 0.01 inches
of their locations on the digitizing source. The digital map elements
are edge matched against the data for the adjacent quadrangle. Edge
match locations generally do not deviate from centerline to centerline
by more than 0.01 inches.

**Source_Information:**

Source_Citation:

Citation_Information:

Originator: \_\_\_\_\_\_\_(13)\_\_\_\_\_\_\_\_\_\_\_\_

Publication_Date: \_\_\_\_\_\_\_\_(14)\_\_\_\_\_\_\_\_\_\_\_\_

Title: \_\_\_\_\_\_\_\_\_(15)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Geospatial_Data_Presentation_Form:
\_\_\_\_\_\_\_\_(16)\_\_\_\_\_\_\_\_\_\_\_

Publication_Information:

Publication_Place: \_\_\_\_\_\_\_\_\_(17)\_\_\_\_\_\_\_\_\_\_

Publisher: \_\_\_\_\_\_\_\_(18)\_\_\_\_\_\_\_\_\_\_\_\_

Source_Scale_Denominator: 24000

Type_of_Source_Media:\_\_\_\_\_\_\_\_\_\_\_\_(19)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: \_\_\_\_\_\_\_\_(20)\_\_\_\_\_\_\_\_\_\_\_

Source_Currentness_Reference:
\_\_\_\_\_\_\_\_\_\_(21)\_\_\_\_\_\_\_\_\_\_\_\_\_

Source_Citation_Abbreviation:
\_\_\_\_\_\_\_\_\_(22)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Source_Contribution:
\_\_\_\_\_\_\_\_\_\_\_(23)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

of Hydrologic Units.

Process_Step:

Process_Description:\_\_\_\_\_\_\_\_\_\_\_(24)\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Process_Date: \_\_\_\_\_\_\_(25)\_\_\_\_\_\_\_\_\_\_\_\_

Source_Used_Citation_Abbreviation: \_\_\_\_\_\_\_\_(26)\_\_\_\_\_\_\_\_

**Spatial_Data_Organization_Information:**

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Complete chain

Point_and_Vector_Object_Count: 19405

**Spatial_Reference_Information:**

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name: Universal Transverse Mercator

Universal_Transverse_Mercator:

UTM_Zone_Number: \_\_\_\_\_(27)\_\_\_\_\_\_

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.999600

Longitude_of_Central_Meridian: \_\_\_\_\_\_(28)\_\_\_\_\_\_\_\_\_\_

Latitude_of_Projection_Origin: 0.0

False_Easting: 500000.000000

False_Northing: 0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: \_\_\_\_\_(29)\_\_\_\_\_\_\_\_\_

Ordinate_Resolution: \_\_\_\_\_(30)\_\_\_\_\_\_\_\_\_

Planar_Distance_Units: Meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geometric Reference System 80

Semi-major_Axis: 6378137.0

Denominator_of_Flattening_Ratio: 298.257

**Entity_and_Attribute_Information:**

Detailed_Description:

Entity_Type:

Entity_Type_Label: \_\_\_\_\_\_\_\_(31)\_\_\_\_\_\_\_\_\_\_\_

Entity_Type_Definition:
\_\_\_\_\_\_\_\_\_\_(32)\_\_\_\_\_\_\_\_\_\_\_\_\_

Entity_Type_Definition_Source:
\_\_\_\_\_\_\_\_\_(33)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute:

Attribute_Label:
\_\_\_\_\_\_\_\_\_\_(34)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute_Definition: \_\_\_\_\_\_\_\_(35)\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute_Definition_Source:
\_\_\_\_\_\_\_\_\_(36)\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute_Domain_Values:

Codeset_Domain:

Codeset_Name: \_\_\_\_\_\_\_\_(37)\_\_\_\_\_\_\_\_\_\_\_

Codeset_Source: \_\_\_\_\_\_\_\_\_\_\_(38)\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute:

Attribute_Label: LENGTH

Attribute_Definition: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute_Definition_Source: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1

Range_Domain_Maximum:2000

Detailed_Description:

Entity_Type:

Entity_Type_Label: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Entity_Type_Definition: \^M

Entity_Type_Definition_Source:\^M

Attribute:

Attribute_Label: FID

Attribute_Definition: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute_Definition_Source: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1

Range_Domain_Maximum:2000

**Overview_Description:**

Entity_and_Attribute_Overview: Hydrologic Unit delineations are closed
polygons that encompass all area draining toward the lowest point
(called outlet) in the polygon. Because of nominal sizes for the
different hydrologic unit level: Watershed (40,000 to 250,000 acres) and
Sub-watershed (generally 10,000 to 40,000 acres), some polygons do not
include all areas up to the drainage divide but all areas to one or more
other upstream hydrologic units. A unique hydrologic unit code is used
to identify each hydrologic unit. The Watershed hydrologic unit codes
start with the 8-digit Sub-basin (Cataloging Unit) number that contains
the Watershed. Likewise the Sub-watershed hydrologic unit codes start
with the 11-digit Watershed number that contains the Sub-watershed.
Attributes associated with a hydrologic unit code includes where
appropriate: non-contributing area (acres);

type of non-contributing area (number of areas, scatter throughout);

trans-basin areas inflowing to hydrologic unit;

trans basin area (acres);

trans basin area originating hydrologic unit code; and

notes concerning delineation of hydrologic unit boundary.

Entity_and_Attribute_Detail_Citation:

Interagency Standards on Delineation of Watershed and Sub-watershed
Hydrologic Unit Boundaries.

**Distribution_Information:**

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Department of Agriculture

Natural Resources Conservation Service

National Cartography and Geospatial Center

Contact_Address:

Address_Type: mailing address

Address: P. O. Box 6567

City: Ft. Worth

State_or_Province: TX

Postal_Code: 76115

Country: USA

Contact_Voice_Telephone: (817) 334 5559

Contact_Facsimile_Telephone: (817) 334 3486

Contact_Electronic_Mail_Address: nrcs_data@ftw.nrcs.usda.gov

**Resource_Description**:
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_(39)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Distribution_Liability:

Although these data have been processed successfully on a computer
system at the U.S. Department of Agriculture, no warranty expressed or
implied is made by the agency regarding the utility of the data on any
other system, nor shall the act of distribution constitute any such
warranty. Neither the U.S. Department of Agriculture, nor any of its
agencies are liable for misuse of the data. Nor is it liable for damage,
transmission of viruses, or computer contamination through the
distribution of these data sets. The United States Department of
Agriculture (USDA) prohibits discrimination in its programs on the basis
of race, color, national origin, sex, religion, age, disability,
political beliefs and marital or familial status. (Not all prohibited
bases apply to all programs.) Persons with disabilities who require
alternative means for communication of program information (Braille,
large print, audio tape, etc.) should contact the USDA Office of
Communications at (202) 720-5881 (voice) or (202) 720-7808 (TDD).

**Standard_Order_Process:**

Digital_Form:

Digital_Transfer_Information:

Format_Name: ARC EXPORT

Format_Version_Date[: \_\_\_\_\_(40)\_\_\_\_\_\_\_\_\_\_]{.underline}

Format_Specification:

Optional

Format Content Information: spatial and attribute

File_Decompression_Technique: No compression applied

Transfer_Size: \_\_\_\_\_\_\_(41)\_\_\_\_\_\_\_\_\_\_\_

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: http://www.ftw.nrcs.usda.gov/nsdi_node.html

Access_Instructions: Local area network

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Access_Instructions: Local area network

Offline_Option:

Offline_Media: CD-ROM

Recording_Format: ISO 9660 Level 1

Fees: The an administrative charge of \$50 for a CD-ROM that contains a
state data set.

Ordering_Instructions: Call or write.

Turnaround: 10 working days

**Metadata_Reference_Information:**

Metadata_Date: 20000518

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: \_\_\_\_\_\_\_\_\_(42)\_\_\_\_\_\_\_\_\_\_\_\_\_

Contact_Organization: Natural Resources Conservation Service

Contact_Address:

Address_Type: mailing address

Address:
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_(43)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

City: \_\_\_\_\_\_\_\_\_(44)\_\_\_\_\_\_\_\_\_

State_or_Province: \_\_\_(45)\_\_\_ State \_\_\_\_\_\_

Postal_Code: \_\_\_(46)\_\_\_\_\_

Country: USA

Contact_Voice_Telephone: \_\_\_(47)\_\_\_\_\_\_

Contact_Facsimile_Telephone: \_\_\_\_(48)\_\_\_\_\_\_\_

Metadata_Standard_Name: Content Standards for Digital Geospatial
Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

**Citation-**

1\. Publication Date - The date when the data set was published or
otherwise made available for release. Enter the year (YYYY) the data is
submitted for archiving and distribution. Example - Publication Date:
1995

2\. Title- The name by which the data set is known. Enter the complete
name and detail level of the hydrologic unit area or state included.
Examples- Title -9908020304 Podunk Creek or 10-digit hydrologic units
for Maryland

3\. Calendar Date - The year (YYYY) the data set is submitted for
archiving and distribution. This is the same as the entry for
Publication Date. Example - Calendar Date: 1995

**Spatial Domain-**

Bounding Coordinates - The limits of a data set expressed by latitude
and longitude values in the order: western most; eastern most; northern
most and southern most. The bounding coordinates are for the hydrologic
unit area or state boundary.

4\. West Bounding Coordinate - Western most coordinate of the coverage
limit expressed in longitude (decimal degrees). Example - 93.328

5\. East Bounding Coordinate - Eastern most coordinate of the coverage
limit expressed in longitude (decimal degrees). Example - 91.328

6\. North Bounding Coordinate - Northern most coordinate of the coverage
limit expressed in latitude(decimal degrees). Example - 41.328

7\. South Bounding Coordinate - Southern most coordinate of the coverage
limit expressed in latitude(decimal degrees). Example - 39.328

**Keywords -**

8\. Place Keyword - The name of the state(s) that include the data set.
Enter multiple states as separate entries. Example - Place Keyword:

Nebraska

Place Keyword: South Dakota

Place Keyword: Wyoming

9\. Place Keyword - The name of the quadrangle for the data set. Enter
the USGS quadrangle name and number from the National Topographic Map
Names database. Example - Hartford Quadrangle (4122N09322W)

10\. Publication Date: - The date when the data set was published or
otherwise made available for release. Enter the year (YYYY) the data is
submitted for archiving and distribution. Example - Publication Date:
1995

11\. Title- The name by which the data set is known. Enter the complete
name and detail level of the hydrologic unit area or state included.
Examples- Title -9908020304 Podunk Creek or 10-digit hydrologic units
for Maryland

12\. Completeness Report: Information concerning any variation from the
standard criteria or definitions used in creating the data set.

**Lineage -** Information about the events, parameters, and source data
which constructed the data set, and information about the responsible
parties. This section can be repeated for additional sources.

13\. Originator: The name of the organization or individual that
developed the data set. Example - Originator: U.S. Geological Survey

14\. Publication Date: - The date when the data set was published or
otherwise made available for release. Enter the year (YYYY) the data is
submitted for archiving and distribution. Example - Publication Date:
1995

15\. Title- The name by which the data set is known. Enter the complete
name and detail level of the hydrologic unit area or state included.
Examples- Title -9908020304 Podunk Creek or 10-digit HUs for Maryland

16\. Geospatial Data Presentation Form - The mode in which the
geospatial data is presented. Example - Geospatial Data Presentation
Form: topographic quadrangle map

17\. Publication Place - The name of the city and state where the data
set was published or released. Example - Beltsville, Maryland

18\. Publisher - The name or the organization or individual that
published the data set. Example - Natural Resources Conservation Service

19\. Type of Source Media - The medium of the source data. Generally
this will be either \"paper\" or \"stable base material\". Example -
Type of Source Media: paper

20\. Calendar Date - Year (YYYY) in which the source data was collected
or represents. Example - Calendar Date: 1993

21\. Source Currentness Reference - The basis on which the source time
period of content information of the source data set is determined.
Generally this will be based on when the boundaries were delineated on
the map. Free form text field. Example - Source Currentness Reference:
map delineation

22\. Source Citation Abbreviation - The short form alias for the source
citation. Example - Source Citation Abbreviation: NRCS

23\. Source Contribution - A brief statement identifying the information
contributed by the source to the data set. Generally \"map
delineation\", :digitize map\", \"financial support\", and / or \"field
verify\" would be appropriate. Example - Source Contribution map
delineation and field verify

**Process Step -** Information about a single event. This section can be
repeated for additional steps.

24\. Process Description - An explanation of the event and related
parameters or tolerances. Free form text. Example - Process Description:
Site verification of trans-basin outlet location in HU 99637621040

25\. Process Date - Year (YYYY) in which the Process Description was
carried out. Example Process Date: 1994

26\. Source Used Citation Abbreviation - The Source Citation
Abbreviation for the group or individual that performed the Processing
Step. Example - Source Used Citation Abbreviation: NRCS

**Numbers in Spatial Reference Information Section:**

Spatial Reference Information is the description of the reference frame
for and the means to encode coordinates in the data set..

**Horizontal Coordinate System Definition:**

27\. UTM Zone Number - The identifier for the UTM zone covered by this
data set. For multiple zones, use a separate entry for each. Example -
UTM Zone Number: 15, UTM Zone Number: 16

28\. Longitude of Central Meridian - The line of longitude at the center
of a map projection generally used as the basic for constructing the
projection. Each UTM zone covers 6 degrees in longitude. Consider UTM
zone 13, which begins at 102 degrees and ends at 108 degrees. The
longitude of central meridian is the center of the zone or 105.
Example - Longitude of Central Meridian: 105

29\. Abscissa Resolution: The minimum (nominal) distance between the
\"x\" or column values of two adjacent points, expressed in Planar
Distance Units of measure. The resolution is dependent upon the source
map scale.

Scale Abscissa Resolution

1:12,000 .305

1:15,840 .402

1:20,000 .51

1:24,000 .61

. Example - Abscissa Resolution: .61

30\. Ordinate Resolution: The minimum (nominal) distance between the
\"y\" or row values of two adjacent points, expressed in Planar Distance
Units of measure. The resolution is dependent upon the source map scale.

Scale Ordinate Resolution

1:12,000 .305

1:15,840 .402

1:20,000 .51

1:24,000 .61

. Example - Ordinate Resolution: .61

Geodetic_Model:(These are parameters for the shape of the Earth. It is
important to use the actual values used when producing the data (which
should be documented with any processing software), not just the values
from some standard reference.)

**Entity_and_Attribute_Information**

31\. Entity_Type_Label: This entry should explain what is described in
the data.

32\. Entity_Type_Definition: The definition should explain what the
entity is, in however much detail is necessary.

33\. Entity_Type_Definition_Source: This is the name of a person,
agency, or document that is the source of the definition above.

**Attribute:**

34\. Attribute_Label: The name of the attribute in the data.

35\. Attribute_Definition: As for Entity, this should be a definition
that explains what the attribute is, in however much detail is
necessary.

36\. Attribute_Definition_Source: The name of the party that is the
source of the definition.

Attribute_Domain_Values: There are four different types of attribute
domain values. An Enumerated Domain is a set list of values, like high,
medium, and low. A Range Domain is a sequence or series of values.
Provide the minimum and maximum from the data set. A Codeset Domain is a
reference to a predefined set of codes, like FIPS or the DLG-3 coding
standards. An non-represented Domain is anything that can't be described
with the other three, like city names (the list is too long for an
enumerated domain, and anything is possible). EXAMPLES of all four
domain types are given below. The different types of domains may also be
combined to describe one set of attribute values, see the examples
below. It is important to provide complete information and to use the
appropriate domain type. This gives the user the most useful information
and reduces the number of requests for further information.

**Codeset_Domain:**

37\. Codeset_Name: Codes for the Identification of the States, the
District of Columbia and the Outlying Areas of the United States, and
Associated Areas

**Federal Information Processing Standard (FIPS)**

38\. Codeset_Source: This is the publisher of the codeset.

39\. Resource Description - The identifier by which the distribution
knows the data set. Example - Resource Description: Podunk Quadrangle,
10 digit HU Boundary

**Standard Order Process**

40\. Format Version Date - The version data (YYYYMMDD) for the format of
the data set. Example - Format Version Date: 19920508

41\. Transfer Size - The size (or estimated size) in megabytes of the
transferred digital data set. This is the sum of the coverage,
shapefiles, and metadata in the data set. Example - Transfer Size: 14.4

**Metadata Reference Information Section**

42\. Contact_Person: The person responsible for the metadata
information.

43\. Address - The street address or box number for the Contact
Organization. Example - Address: 111 Main Street, Room 15

44\. City - The city name for the Contact Organization. Example - City:
Springfield

45\. State or Province - The name of the state for the Contact
Organization. Example - State or Province: Ohio

46\. Postal Code - The ZIP code for the Contact Person. Example - Postal
Code: 44444-5678

47\. Contact Voice Telephone - The telephone number (including area
code) for the Contact Organization. Example - Contact Voice Telephone:
(410) 555-1234

48\. Contact Facsimile Telephone - The FAX machine that services the
Contact Organization. Example - Contact Facsimile Telephone: (410)
555-5678