Alaska Watershed Delineation Project

Introduction

The purpose of this project is to delineate 5^th^ and 6^th^ level
Hydrologic Units, provide a routed stream coverage, and ultimately to
vertically integrate our NRCS certified watersheds with the NHD and EDNA
products.

## Watershed Delineation Overview

A process for watershed delineations has been developed by EDNA
(Elevation Derivatives for National Applications) previously known as
NED-H. The delineation of 5^th^ and 6^th^ level watersheds and
subwatersheds will be done using the EDNA Stage 2 Tools and following
the *Federal Standards for Delineation of Hydrologic Unit Boundaries*.
The 5^th^ and 6^th^ level hydrologic units will then be sent to the
Natural Resources Conservation Service (NRCS) for certification into the
Watershed Boundary Dataset (WBD). The goal is a national seamless
hydrography dataset.

**5^th^ and 6^th^ Level Hydrologic Unit Guidelines**

# Hydrologic Unit Size and Number Criteria (Alaska Specific)

+------------+---------------+--------+-------------------+-----------+
| **         | # Name        | **     | **Size (in        | # Number  |
| Hydrologic |               | Coding | acres)**          |           |
| Unit       |               | Di     |                   |           |
| Level**    |               | gits** |                   |           |
+------------+---------------+--------+-------------------+-----------+
| 1          | Region        | 2      |                   |           |
+------------+---------------+--------+-------------------+-----------+
| 2          | Sub-region    | 4      |                   |           |
+------------+---------------+--------+-------------------+-----------+
| 3          | Basin         | 6      |                   |           |
+------------+---------------+--------+-------------------+-----------+
| 4          | Sub-basin     | 8      | 250,000-450,000   |           |
+------------+---------------+--------+-------------------+-----------+
| 5          | Watershed     | 10     | 40,000-250,000    | 10 to 20  |
+------------+---------------+--------+-------------------+-----------+
| 6          | Sub-watershed | 12     | 10,000-40,000     | 10 to 15  |
+------------+---------------+--------+-------------------+-----------+

The Hydrologic Unit Code (HUC) for the Alaska Region is 19. Alaska has
six sub-regions, 33 basins and 136 sub-basins. The national standard for
the number of 5^th^ level watersheds is 5 to 15, for Alaska it is 10 to
20. This is because Alaska 4^th^ level sub-basins are, on average,
larger than the national standard. These guidelines are to ensure the
consistency of watershed data throughout the nation.

**Definitions**

Seed point -- Pour point for a watershed or subwatershed

Catchment -- The contributing drainage area for a reach

Pfafstetter system -- A self-replicating numbering scheme based upon the
topology of the drainage network and the size of the surface area
drained which allows for identification numbers of the smallest
subbasins extractable from a DEM.

## Watershed Delineation Process

The USGS has developed watershed delineation tools for ArcView.
Employing the Pfafstetter coding scheme and Avenue scripts, catchments
were derived for each stream segment. Using the synthetic streams,
derived from DEMs, we can aggregate the upstream catchment areas into
one watershed. The furthest downstream point in each watershed is known
as the seed point.

![](media/image1.wmf)

The procedure is fully automated and once complete will generate
shapefiles that will comprise the 5^th^ and 6^th^ level hydrologic
units. These files will be sent to cooperators for review and approval
of the preliminary watersheds. The final files will be processed by the
AK BLM incorporating changes proposed by the cooperators. These files
will be QA/QC for errors and sent to the USGS for Stage 3 EDNA
processing.

## EDNA End Products

The primary products will be 5^th^ and 6^th^ level hydrologic units and
a revised elevation data set. EDNA Stage 3 processing will produce a
vertically integrated, hydrologically conditioned and fully seamless
dataset facilitating modeling and analysis. Vertical integration means
that all the data (NHD, EDNA, WBD) will be in the same scale and same
projection. Hydrological conditioning is designed to determine flow
direction, slope, gradient, watershed area, and flow accumulation at any
place on the stream line. A seamless dataset allows data to be used in
any size research area so each user can manipulate a manageable and
desirable dataset. Existing DEMs will become the updated EDNA to
correspond with the other datasets and to better illustrate "reality."

## Metadata

As outlined in the *Federal Standards for Delineation of Hydrologic Unit
Boundaries,* FGDC compliant metadata must be completed for all datasets.

## National Certification

The final watershed data will be sent to the National NRCS
representative for certification and inclusion into the National WBD.

## References

*Federal Standards for Delineation of Hydrologic Unit Boundaries*, June
12, 2001.

Hanson, Karen. *Hydrologic Unit Boundary Delineation Process Used in
Utah*.

Lal, Harbans, et al. *Stream Routing Tool (SRT) User Guide and
Documentation*, Version 1.4.1, May 1999. Pacer Infotec, USDA Forest
Service.

*National Hydrography Dataset: Concepts and Contents*, April 1999.

*NED-H Stage 2 Tool Overview*, ArcView Help Topics, Oct 31, 2000.

U.S. Bureau of the Budget. *National Mapping Program Standards: United
states National Map Accuracy Standards*, June 17, 1947.

Verdin, Kristine L. *A System for Topologically Coding Global Drainage
Basins and Stream Networks*, May 16, 2001.

## 

## 

## 

## 

## 

## 

## Appendix

Exhibit 1: *Alaska Hydrologic Unit Delineation Chart*

Exhibit 2: *FTP Guide for MS DOS*

Exhibit 3: *WS-FTP Guide*

## ![](media/image2.jpeg){width="5.011805555555555in" height="8.995138888888889in"} 

Exhibit 2: **Ftp Guide for MS DOS**

To determine the IP address of a computer in the Windows environment
type in the following at the MS-DOS command prompt:

C:\\IPCONFIG (For NT machines) C:\\ INIPCFG (For Windows 98 machines)

# 

![](media/image3.png){width="5.357638888888889in"
height="1.8895833333333334in"}

1\.

2\.

~3.~

~4.~

~5.~

~6.~

Before entering the ftp prompt, the directory that the new file to be
transferred to must be designated. For example, if the file needs to be
placed in the nhd directory, the following path could be used\... *cd
/work/agoo/nhd*. When done proceed to step 1.

1\. At the MS-DOS prompt type \"ftp\" and the Alaska BLM ftp site

**C:\\ ftp *ftp.akso.ak.blm.gov***

For retrieving use the IP address provided, for example:

**C:\\ ftp *136.177.111.5***

2\. After step 1 the ftp prompt will appear. Type in \"anonymous\"

**ftp\> anonymous**

3\. For the password use your e-mail address

**ftp\> *agoo@ak.blm.gov***

4\. Type \"cd incoming\" for placing the item to be ftp\'d. Incoming is
the directory the

Alaska BLM uses.

**ftp\> cd incoming**

If trying to retrieve files then type \"cd\" *and* the directory where
the item is located. Use the command *dir* and *ls* to determine what
directories and files are available.

**ftp\> cd *nhd-updates/from_kirk/arc***

**\*NOTE\*** It may be necessary to change directories (*cd)*
individually

5\. Type in \"bin\" to transfer to binary. This allows the ftp to
recognize the format

**ftp\> bin**

6\. Type \"put\" and the file name that is to be sent to the ftp site.

**ftp\> put *arimsuser.doc***

To retrieve a file type \"get\" and the file to be uploaded

**ftp\> get *nhd-dataset***

7\. Type \"quit\" to exit ftp

**ftp\> quit**

Exhibit 3: WS_FTP Guide

![](media/image4.png){width="3.6756944444444444in"
height="2.8652777777777776in"}

To ftp from a new site, click the Ne[w]{.underline} button. This clears
all the information and allows you to provide a new profile name and
address. This can later be accessed through the drop-down menu at
Profile Na[m]{.underline}e.

1.  Profile Na[m]{.underline}e: *sun2nt* (this can be anything you want
    to call this connection that will help you remember what it is.)

2.  Host [N]{.underline}ame/Address: *158.68.9.194* (this is the IP
    address that we are connecting to, it can also be in the format
    *ftp.akso.ak.blm.gov*)

3.  Host [T]{.underline}ype: *Automatic detect* (this is the default, it
    does not need to be changed)

4.  [U]{.underline}ser ID: *xsotelo* (If a User ID is required, you
    should use yours. If not, click the [A]{.underline}nonymous
    checkbox)

5.  [P]{.underline}assword: this only applies if you need a User ID, if
    [A]{.underline}nonymous is chosen, an e-mail address is used.

6.  A[c]{.underline}count: this can be left empty

7.  C[o]{.underline}mment: If you would like to explain anything about
    the connection, you can do so in this field.

In the window that comes up, you will have a local system and a remote
site. The remote site is the location you connected to; the local system
is your own computer. If you are ftping to your own computer, browse to
the directory where you want to put the file in the local system window,
then in the remote site window browse to and select the file you wish to
ftp; press the arrow button pointing toward the local system window. The
file should be copied. You can also ftp from your local system to a
remote site.