Watershed Index Online (WSIO) User Manual


The Watershed
Index Online
User Manual

The Watershed Index
Online (WSIO) User
Manual

An Enhanced Scoring
Application for Comparative
Watershed Assessment

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The WSIO User Manual

Table of Contents

Abbreviations	iv

I.	Introduction	1

A.	Comparative Watershed Assessment	1

B.	About the Watershed Index Online Project and Tool	1

1.	The Watershed Index Online Project	1

2.	The WSIO Tool	1

C.	Preparing to use the WSIO Tool	2

1.	Obtaining the WSIO Tool	2

2.	Selecting a Project Area	2

3.	Selecting Indicators	2

II.	WSIO Tool Step-by-Step Instructions	5

A.	RUN WSIO Tool and Select Data Source	5

B.	Build or Open a Project	5

1.	A new project	5

2.	Open an existing project	5

3.	Build a user database of indicators	5

C.	WSIO Project Description and Select Geography	6

D.	Save Your Project	7

E.	Finalize HUC Selection	7

1. Map window hints	8

III.	Indicator Selection	13

A. Select Ecological, Stressor and Social Indicators	14

1. Indicator selection helpful hints	15

a)	Indicator definitions	15

b)	To select multiple indicators	15

c)	To remove indicators from selection	15

d)	To remove all indicators from a category selection	15

e)	Using a 'Neutral Variable'	15

f)	Applying a weight factor	15

i

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IV.	WSIO Screening Results	16

A.	Indicator Data	16

B.	Run Indicator Correlations	16

1.	Change your indicator selection	17

2.	Change your HUC selection	17

V.	WSIO Screening Results	18

A.	WSIO Scores page helpful hints	19

B.	Map Indicator Scores	20

1. Map symbology hints	21

C.	View Watershed Index Scores and Indicator Values for each HUC12 watershed	22

VI.	Open an Existing Project	23

A. Save-As	23

VII.	Build a User Database of Indicators	24

VIII.	References	27

IX.	Glossary	28

Table of Figures

Figure 1: Riparian Zone and Hydrologically Connected Zone mask applied to the same waterbody	3

Figure 2. Example project area selection using a State filter	7

ii

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Disclaimer and User Requirements
Software requirements: At least a Windows 7 operating system and Microsoft .NET
Framework 4.5 and above. Mention of product names does not denote endorsement by
the EPA.

The WSIO is intended to be used as a decision-support tool by government, professional,
academic, and community users with a basic understanding of how the ecological condition
of a watershed and the stressors that act upon it can affect hydrology, biology, and water
quality. The WSIO data and tool outputs do not represent, change or substitute for any
statute, regulation, policy, EPA decision or position.

It is the responsibility of the user to read and evaluate dataset limitations, restrictions,
and intended use. To the best of our knowledge, the data, information, and supporting
materials on the WSIO website are accurate; however, no warranty expressed or implied is
made regarding the accuracy or utility of the data for general or scientific purposes, nor
shall the distribution constitute any such warranty. All modeled geographic data are, by
their nature, imperfect. The data provided by this tool shall not be taken as absolute truth,
but rather as an approximation made in good faith based on the best available data.
For site-specific data, WSIO data will not replace "boots-on-the-ground" measurements or
local knowledge. Better local data may be available from local sources.

Neither the EPA, EPA contractors, nor any other organizations cooperating with the EPA
assume any responsibility for damages or other liabilities related to the accuracy,
availability, use or misuse of the information provided on this website. The EPA reserves
the right to change information at any time without public notice. Any errors or omissions
should be reported to the WSIO team using "Contact Us" on the WSIO website. We are
always happy to hear your feedback and use that feedback for future enhancements.

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Abbreviations

EA

Environmental Atlas

EEA

Essential Environmental Attributes

EPA

Environmental Protection Agency

GIS

Geographic Information System

HCZ

Hydrologically Connected Zone

HUC

Hydrologic Unit Code

HWI

Healthy Watershed Initiative

MS

Microsoft Corporation

NHD

National Hydrography Dataset

NLCD

National Land Cover Data

NPDES

National Pollutant Discharge Elimination System

NRCS

Natural Resources Conservation Service

RPI

Recovery Potential Index (Score)

RPS

Recovery Potential Screening

RZ

Riparian Zone

SAB

Scientific Advisory Board

TMDL

Total Maximum Daily Load

WBD

Watershed Boundary Data

WS

Watershed

WSI

Watershed Index (Score)

WSIO

Watershed Index Online

iv

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I. Introduction

A, Comparative Watershed Assessment
Federal, State and Local water quality programs are increasingly using comparative watershed
assessment tools to inform their decisions about how to prioritize watersheds for restoration and
protection activities in the context of their overall water quality goals. Comparative watershed
assessment involves systematically evaluating large numbers of watersheds, in order to identify and
communicate the similarities and differences among them. This type of assessment requires that data
on various watershed attributes (such as land cover, hydrology, slope, soils, biology, water quality, etc.)
be consistently translated into "indicators" of watershed condition and drivers of change (stressors) for
the watersheds being compared. The Watershed Index Online (WSIO) is a free, publically available data
library of watershed indicators and a decision-support tool, developed by the EPA, to assist resource
managers with evaluating, comparing, and prioritizing watersheds to support the user's objectives.

B, About the Watershed Index Online Project and Tool

1.	The Watershed Index Online Project

The Watershed Index Online (WSIO) project was initiated in 2008 by the EPA Region 4 WPD and
collaborators, to improve ways to compare, prioritize and target watersheds for a broad range of
watershed management purposes. The EPA Office of Water Recovery Potential Screening (RPS) project
is the primary partner in the WSIO's development. During the past several years, Region 4's WSIO team
and others compiled a substantial national database of watershed characteristics; while, the RPS project
developed and applied an Excel-based watershed comparative scoring tool for each of the 48 contiguous
US states. The WSIO merges these efforts into a single product by combining the WSIO indicator
database and an enhanced version of the RPS tool; creating a watershed analysis application resource
that is able to cross state boundary lines.

2.	The WSIO Tool

The WSIO Tool was developed to assist federal, state, and local partners in prioritizing activities based
on watershed condition and suitability or need for protection, restoration, improved monitoring, and
other management activities. The goal of the WSIO project is to increase the capacity for states and
others to perform comparative watershed analysis by providing a watershed comparison tool and a
library of more than 300 of the most popular watershed indicators. These attributes have been
measured consistently for all 83,015 12-digit Hydrologic Unit Code (HUC12) watersheds (e.g., 40-square
mile average size) in the contiguous United States and is hosted as a map service

(https://gispub.epa.gov/arcgis/rest/services/r4/WSIO/MapServer). The WSIO Tool allows users to easily
choose uniformly measured watershed indicators for a defined project area, to generate and assess
comparative rankings for those watersheds based on ecological, stressor, and social context indicators
selected by the user, and to save a variety of watershed comparative screenings for further analysis or
export of tables, maps, and plots.

1

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C, Preparing to use the WSIO Tool

1. Obtaining the WSIO Tool

The WSIO Tool is available for download directly from the WSIO website located here:
https://www.epa.gov/wsio/introducing-wsio-national-watershed-library-and-tools. by clicking on the
WSIO Tool link at the bottom of the page.

2. Selecting a Project Area

There are two steps in the WSIO process where the user can specify a geographic area, there are
different considerations for each stage. The first time the user is selecting watersheds within a State,
HUC6, EcoRegion, or EPA Region. This step is performed on the Project page of the application and it
defines the selectable project area. It is recommended that the user be inclusive and that the project
area be hydrology-based (i.e. river basin), although geographic areas such as a state boundary may also
provide suitable project areas. It is recommended to avoid selecting too small of an area because
smaller project areas do not provide sufficient hydrologic, ecological, topographic, and physical variety
to provide context for normalizing indicators and ranking watersheds.

The second time the user can select a geographic area is when selecting HUC12 watersheds on which to
perform a screening. This step is performed on the Map tab and it defines the screening area, allowing
the user to focus on sub-set(s) of the larger project area selected in the first step. Multiple screenings
can be performed and saved by clicking on Save As in the Project menu and renaming your project file.
The project area provides the setting (context) for the analysis, the screening area allows the user to
focus in on a sub-set of the larger project area.

3. Selecting Indicators

a) About Indicators

A watershed indicator is an attribute of a watershed that is useful for watershed comparison and can be
consistently measured throughout the geographic area of interest. Most of the WSIO's several hundred
indicators are derived from geospatial data analysis, although some come from field monitoring and
other information sources that have been geospatially referenced to watersheds. Indicators in the
WSIO database are grouped by three Indicator Types: Ecological, Stressor, or Social classes which
encompass the most desired data used in many watershed comparisons. Indicators also include
different spatial extents, depending on whether the indicator represents the entire HUC12 watershed
(WS), or just the stream corridor, as represented by the Hydrologically Connected Zone (HCZ) or the
Riparian Zone (RZ) (See: Glossary). A comparison of the RZ and HCZ masks applied to the same
waterbody is shown in Error! Reference source not found. For more information on WSIO Indicators, a
list of available indicators and their definitions can be downloaded from the WSIO website, in addition
to Indicator Data tables (https://www.epa.gov/wsio/data-tables-and-map-services). Indicators specific
to a region or project area can also be developed by the user and incorporated into the Tool (See: Build
a User Database of Indicators).

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Figure 1: Riparian Zone and Hydrologically Connected Zone mask applied to the same vjaterbody.

b) Indicator Correlations
The WSIO Tool allows the user to see correlations among the same type of selected Ecological and
Stressor indicators. This function is included to aid in the selection of indicators by providing the user the
ability to see the strength and direction of the relationship between them. The value of correlation
coefficients ranges from 1 to -1. The closer the value is to ±1, the stronger the relationship between the
two indicators; the closer the value is to 0, the weaker the relationship. Positive values indicate that the
variables change in the same direction, while negative values express an inverse relationship. The Tool
provides results for two correlation types: Pearson and Spearman Correlations.

The Pearson Correlation assumes that both variables are normally distributed, have a straight line
relationship between them, and are normally distributed about the regression line. The Spearman
Correlation is a nonparametric version of the Pearson Correlation, and is useful when the relationship

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between two variables in expected to be non-linear. A small p-Value of <0.05, indicates that you can
reject the null hypothesis that these two indicators do not have a relationship. The higher the p-value,
above 0.05, indicates that you can accept the null hypothesis that these two indicators do not have a
direct relationship.

4

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II. WSIO Tool Step-by-Step Instructions

A. RUN WSIO Tool and Select Data Source
Run the WSIO Tool by opening the executable file, 'WSIO.exe.' The application will open with the
option to use a 'Web Service' or a 'Local Geodatabase' to pull in indicators to the tool. The Web Service
requires an internet connection for data transmittal. The most current version of these indicators will
be available through the Web Service and for download from the WSIO website. Once you have
selected your data source, click 'OK.'

WSIO

WSIO - GIS-based Watershed Index Online.

Version 1.0

ijh

US EPA R4 WPD/WQPB/DIAS

Please select a data source for the Watershed Index Online (WSIO) database. The
WSIO database stores indicator data for HUC12 watersheds.

Data source options are:

Web Service - This option accesses the online WSIO database hosted by US EPA. You
must have an internet connection to use the tool with this option.

Local GDB - This option uses a copy of the WSIO database stored on your local hard
drive. By selecting this option you can use the tool while offline.

Data Source

o Web Service https://gispub.epa.gov/arcgis/rest/services/r4/wiso/MapServer
; Local GDB E:\wsioapp\WSIOv2.0_170209.gdb

Initializing toolkit

[ Cancel _] [ OK ]

B. Build or Open a Project
The application will open with a blank workspace. Click on the 'Project' tab to be able to start a new
project, open an existing project, or to build a user database of indicators.

1. A new project

Click on 'New' and continue to WSIO Project Description and Select Geography

2. Open an existing project
Go to Open an Existing Project

3. Build a user database of indicators
Go to Build a User Database of Indicators

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C. WSIO Project Description and Select Geography
A 'Project' window opens, allowing you to name your project, choose where to save it, add a
description, and begin to select your geographic area of interest. The selections made below will create
a boundary for your project.

First, use the geography buttons to select the category (States, Basin (HUC6), EcoRegion, and EPA
Region) that best suits your needs. The lower left table wiil populate with selection options. This
selection wiii determine the broadest geographic area of HUC12s that will be available for use in a WSIO
project. It is recommended to select the largest possible area of HUCs you may need for a screening at
this step; to select more than one option (two states, for example), hold the CTRL button down while
making multiple selections. Once complete, click 'Get HUC12s' (#1) to populate the lower right table. A
subset of HUCs from this list may be selected at this step for a screening run (although all HUCs within
this table wiil be brought into your project), or within the map window of your project. Once finished
with this list click 'Select HUC12s' (#2), then 'Create Project' (#3).

WSIO Project

Project Name Untitled .wsio
Project Folder E:\wsioapp\data
Description Untitled

Browse

The selections made below will create a boundaiy for your project. First, use the geography1 buttons to select the category {States. Basin (HUCS). EcoRegion, and
EPA Region) that best suits your needs. Highlight one or more areas of interest for that geography - this will create the largest selectable area for your project - and
click the 'Get HUC12s' button. The HUC 12s table will populate; by default, all HUC12s are selected. You can reduce the number of selected HUCs here in the
HUC 12s table, or in the map window of your project. Click on 'Create Project' to finalize a WSIO project setup.

Geography

(®) States

0 Basin (HUCS)

EcoRegion

Region

1—

.Alabama

Arizona

Arkansas

California

Colorado

Connecticut

Delaware

District of Columbia

Rorida

Georgia

Idaho

Illinois

Indiana

Clear Selection I Get HUC12s

III

WATERSHED

HUC12

SUBWTRSHED

Middle Chattahoochee...

031300020601

Hillabahatchee Creek

Middle Chattahoochee...

031300020602

Town Creek-Hillabahat...

Middle Chattahoochee...

031300020603

Town of Mason-Cedar...

Middle Chattahoochee ..

031300020802

Upper Wehadkee Creek

Middle Chattahoochee...

031300020803

Little Wehadkee Creek

Middle Chattahoochee..

031300020804

Meacham Creek-Cuss...

Middle Chattahoochee..

031300020805

Veasey Creek-West P...

Middle Chattahoochee...

031300020806

Lower Wehadkee Creek

Middle Chattahoochee...

031300020808

Lower West Point Lake

Middle Chattahoochee...

031300020901

Wells Creek

Middle Chattahoochee...

031300020902

Oseligee Creek

Middle Chattahoochee..

031300020903

Barrow Creek-Chattah...

~ear Selection

3 C

Create Project

]

The HUC12 watersheds that wiil be downloaded, arid therefore made available for inclusion in a
screening run, are the ones that are wholly or partially included in whatever area is defined by the
filter geography type selected, even if the HUC12s intersect the state line, ecoregion, or EPA Region
boundary. For example, if the user selects to filter based on a State," selects "Tennessee" as the
only value, and then filters for HUC8 "05110002 (Barren)" (a watershed that crosses the state line
with Kentucky), the watersheds retrieved by the download will be any HUC12 (05110002####) that

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lies wholly or partially within the state of Tennessee, but will not include HUC12s wholly within the
state of Kentucky (see Figure 2). If the user intended to download/screen the entire HUC8,
regardless of the state it drains, the options include filtering based on a State(s), including both
"Tennessee" and "Kentucky" as values, and then selecting HUC8 "05110002 (Barren)." Another
way of accomplishing this would be to filter based on the HUC6 "River Basin," select "051100
(Green)," and then filter for HUC8 "05110002 (Barren)." As long as the filtered geographic area
encompasses the entire HUC8 watershed, the downloaded dataset should include all of the
HUC12s that comprise the parent HUC8.

It is also important to note that, since the watershed indicators are calculated at the HUC12 scale,
any indicator data brought into the project represents the entire areal extent of the associated
HUC12, even if the watershed crosses a political boundary outside of the filter area. The exception
to this is when the political boundary is the U.S. border with Canada or Mexico. For any HUCs that
cross the U.S. border, the data for an area of the HUC only represent the portion within the U.S.

Kentucky

Legend

Tennessee

| Selected HUC12s using State filter = TN

All HUC12s in 05110002

Barren River HUC 05110002

Figure 2. Example project area selection using a State filter.

D. Save Your Project

Save your project often by clicking on 'Project' in the main header menu, then 'Save.'

E. Finalize HUC Selection

Use the map within the 'Map' tab to finalize or change HUC12 selections for a screening run. The map
contains all HUC12s listed in the HUC12 table from the previous 'Project' window. Selected HUCs from
the previous window will appear shaded in aqua. Here you are able to add or remove HUCs from

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selection, as long as they were part of the initial geography. Use the 'Select' icon in the map menu bar
and hold down the CTRL button when selecting multiple HUCs on the map, or else all other HUC
selections will be removed. HUC12 selections will automatically update within the project. Once you
have HUCs selected, click on the 'Watershed Indicators' tab to choose indicators to use with the HUCs
that have been selected. See below for a few map use and HUC search/selection tips.

¦1? WSIO-C:\Users\EMCGUIRE\Desktop\wsioapp\data\Untit1ed.wsio

alB bs |

Project About

a-r

I Map l/Vatershed Indicators

About

	| Ready.

X: -9859331.5036 Y: 4184167.8086 Untitled.wsio: 1484 features selected

1. Map window hints

a) Navigation menu

Click on the various GIS icons to pan, zoom in and out of an area, make HUC
selections or browse the attribute table of a layer.

Add/Remove layer Pan

: Co L© ii $

Zoom Options

Select/
deselect

View Attribute
Identify	Table





_Q o



# 0

8

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b) Identify

Click this arid then a map feature to identify. Map labeling may serve as a good
alternative to using this tool.

c) Map labeling

Right click on the HUC layer within the legend for additional symbology options.
To enable labelling of the layer, click on 'Labeling/ then 'Label Setup.'

Legend

Tools

' Map Layers

El 0 Online Basemap

B 0|uSHUpl
~

X Remove Layer
g Zoom to Layer
I I Attribute Table Editor

i	 Set Dynamic Visibility Scale

Data	~

Labeling

"¦ft Selection	~

Properties
^ Join Excel file 'Data' Label

J-



Jl

AT

I

r) Label Setup

Set Dynamic Visibility Scale

In the window that appears, you can select the field that you wish labeled. In
this example, 'HUC12' was selected and it appears in the 'Expression' window.
Click 'OK.'

Feature Labeler

MJIU.WBI

I 9 i n

Expression Basic Properties Advanced Properties Members
f Expression ]

[DiSi

Field Names

Name
HUC8

Datatype
String

SUBWTRSHED | String
FID	I Int32

I New line

Example
[Area] + "ha"

[PopulationJ/IOOO + "thsnd."

[Area]

= name of the field

"ha"

= string constant

+ -/*

= arithmetic operators



= concatenates



constants and



fields

Use the Expression Tab to design the text that should
appear in a label. Fields indicated with brackets will be
substituted with real values.

9

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d) Add a basemap

Click on the list in the navigation menu and choose your desired basemap.

Project Select HUCs Download WSIO Indicators Indicator Correlation;
lap

Legend | Tools

B iP Map Layers

- V Online Basemap

B ® USHUCS
~

Esri Hydro B,

Esri World Imagery
Esri World Topo
Bing Street Map
Bing Aerial Map
Bing Hybrid Map
Google Map
Google Labels
Google Terrain
Open Street Map
WMS
Other

HI	\

e) Set basemap Transparency

Once a basemap has been selected, click on the opacity dropdown list to select
the level of transparency desired.

Project Select HUCs

i-i-i 41 ¦-

lap

Downltu

£2 tf)

Legend Tools
B fe? Map Layers

B 0 Online Basemap

B ® USHUCS
~

I WSIO Indicators Indicator Correlation:

" O j_V © ~

Esri World Street fv

WSIO Screening
^ 60

About

None

- EsrjHydroB«eMap

Esri World Imagery
Esri World Topo
Bing Street Map
Bing Aerial Map
Bing Hybrid Map
Google Map
Google Labels
Google Terrain
Open Street Map
WMS
Other

-HI		

OPACITY

f) Select HUCs using the attribute table

**Warning** When you open the Attribute Table, the HUC12 Selections that have been
made will be unselected. This is something we are hoping to fix in a future version.

Right click on HUC12 layer in the Legend and select 'Attribute Table Editor.'
Select the HUC12s for your project by holding the CTRL button, or select
everything between two HUC12s by using the Shift key. Using the Attribute
Table is also the best way to select all the HUC12s within a HUCS or HUC10
watershed.

10

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a£ WSIO-C:\Users\EMGGUIRE\Deslctop\Tools\WSIOvl-051017\data\Untitled.wsic

Project Select HUCs Download WSIO Indicators Indicator Correlations

m a iifili! n « h -a © o ii ,:t>¦%>

Map

Legend Tools

B

f Map Layers

B EZ1 flJntitled.y _

^ Remove Layer

B 0 WSIOHU ^ Zoom to Layer

~

Attribute Table Editor
|_ Set Oynamic Visibility Scale
Data	~

Labeling	*

Selection	*

Properties

Join Excel file 'Data' Label

None

	z	1	i	r J-I—I •.	E—¦	d	a	1	1M ***** *"¦ln •*	li				1—e	k—j	

Attribute Table Editor 	l°"; 2 'I

Edit View Selection Tools

IS] i ip i£>

I HUCS HUC12 SUBWTRSHED FIDO



>

~

031300D2

031300020601

Hillabahatchee Creek

0



03130002

031300020602

Town Creek-Hillabahatchee Creek

1

031300D2

031300020603

Town of Mason-Cedar Creek

2

03130002

031300020802

Upper Wehadkee Creek

3

03130002

031300020603

Little Wehadkee Creek

4

03130002

031300020804

Meacham Creek-Cuss Creek

5

03130002

031300020605

Veasey Creek-West Point Lake

6

03130002

031300020806

Lower Wehadkee Creek

7

03130002

031300020808

Lower West Point Lake

8

031300D2

031300020901

Wells Creek

9

03130002

031300020902

Oseligee Creek

10

03130002

031300020903

Barrow Creek-Chattahoochee River

11

03130002

031300020907

Moores Creek

12

C:\Users\EMCGl

JI RE'.Desktop'1,Tool

s\WSIOv1-060717',data\Untitlec 1 of 14

34 selected.

Close

—

]

11

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1. You can also search the Attribute Table using a query to select all the
HUC12s within a HUC8 watershed. Click on 'Query' in the menu bar to
open the 'Expression Editor' window. You can then create an equation
to easily find your HUCs of interest, like the below example, where all
HUC12s within the HUCS 03130002 were selected.

[^J Attribute Table Editor

I

Edit View Selection Tools

El !> J [ ^ )

HUCS

HUC12

SUBWj]

03130002

031300020601

Hillabah.=

03130002

031300020602

Town Cre

03130002

031300020603

Town of

03130002

031300020802

Upper W

03130D02

031300020B03

Little Wei

03130002

031300020804

Meachan

03130002

031300020905

Veasey C

03130002

031300020806

Lower W

03130D02

0313D0020808

Lower W

03130002

031300020901

Wells Cre

03130002

031300020902

Oseligee

03130002

031300020903

Barrow Ci

03130D02

031300020907

Moores C

Expression Editor

Field Names:

C:\Users\E MCGUIRBD esktopYToolsWVS lOv

Unique Values

HUC12

SUBWTRSHED
FIDO

Is Null

Is Not Null

ED
0
0
0
>¦ <-

~ 0

Like

And

Not

Get
Unique
Values

Minimum: 1031300..

Maximum: 106030Q..

SELECT'FROM [Attributes] WHERE

PJCS^=0313D002J

12

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III. Indicator Selection

An indicator is a simplified measure of the state or condition of something that is too complex to
measure directly. Since it is not possible to measure every aspect of the natural environment,
indicators are used to gain insight into what is happening, such as whether environmental
conditions are improving, deteriorating, or holding steady. As used in the WSIO, an indicator is an
attribute of a watershed that is relevant to its ecological condition and/or the natural or
anthropogenic forces either supporting - or stressing - its health. For example, the percentage of
natural cover in a watershed may be used to indicate the extent to which its natural habitats are
undisturbed, as well as expected levels of anthropogenic pollution and alteration of natural runoff
and infiltration patterns over the landscape. Similarly, the percent impervious cover in a
watershed may be used to indicate the extent to which the natural overland flow to the streams
has been altered. Since protection of drinking water is an issue that typically engages public
concern, the percentage of drinking water source protection areas in a watershed may be used to
represent the likely level of public support and involvement in restoration and protection activities.
For indicators to be useful for comparing and contrasting watersheds, it is important that they be
consistently measured for each watershed within the geographic area of interest.

The WSIO's watershed indicators are grouped based on the type of influence they have on
watershed condition. The WSIO Tool identifies these groups as Ecological, Stressor, and Social
Indicators (See the Glossary for definitions). A logical starting point for developing a list of
potential indicators for a screening is to think about the project's objectives and what factors
might be important in those watersheds. The WSIO Tool requires at least one indicator be selected
in the ecological, stressor and social indicator categories, but it is recommended that a screening
include a variety of indicators. However, keep in mind that the indicator values are effectively
averaged in the Index score, so the more indicators included in the screening calculations, the less
influence each individual indicator will have on the score.

The usefulness of any screening analysis is dependent on the relevance of the indicators used to
the purpose of the screening, as well as the applicability of those indicators to the watersheds and
communities comprising the project area. Familiarity with the project area and an understanding
of how the landscape and hydrology affect the fate and transport of pollutants will help the user
identify factors that are likely important in those watersheds. The purpose of the screening, and
the questions being asked, will also inform indicator selection. If the project is investigating
nutrient enrichment in purely urban watersheds, there is almost certainly no need to include an
indicator related to agricultural water use. However, if the purpose of the screening is to help
identify the most stressed agricultural watersheds, that indicator may be a good selection. As
another example, a project that aims to screen an entire state to identify the relative condition of
all of its watersheds will likely pick a different set of screening indicators than projects that are
focused on waters impaired by bacteria. If projects are focused on different pollutants (e.g.
nutrients vs. bacteria vs. metals), they will probably select different indicators based on the
expected pollutant sources and the fate and transport of the pollutants in watersheds.

-------
Since there are many factors affecting watershed condition and recoverability, most screening
analyses will benefit from using a variety of indicators that represent different types of influence.
Some indicators represent similar attributes, for example: % Woody Vegetation in Watershed, %
Forest in Watershed, % Mixed Forest in Watershed, and % Evergreen Forest in Watershed. It is
preferable to select the forest indicator that best represents the type or amount afforested land
desired for the project objectives. It is not recommended to use both RZ and HCZ for the same
indicator in the same screening; generally, the user should choose the corridor representation that
best suits their objectives.

A. Select Ecological, Stressor and Social Indicators
The 'Watershed Indicators' tab has tables on the left side of indicators available for selection grouped
by Ecological, Stressor, and Social categories. From the list of the WSIO Indicators in each section, select
the indicators you would like to process by clicking on rows of the grid while holding down the CTRL key.
When you have selected an indicator you will see it appear in the box on the right. Once you have
completed your indicator selections, click on the upper left navigation menu 'WSIO Screening' to
download the corresponding indicator data into your project.

WSIO- E:\wsioap p\d ata\U ntitled .ws io
Project About

ED : I None

Map 1 Watershed Indicators

I =. Ce) S3 j

Click on row header to select indicators. Ctrl-Click to select multiple indicators.

Selected Indicators

~ear Selection

Stressor Indicators

Social Indicators

IndicatorName

Tipe

—

PHWA Water Quality Sub-Index, ER (20

... sys

Slope. Standard Deviation in WS

sys

Soil Stability. Mean in WS

sys

1 Cail St-abilit.. in UP7 coxo

| IndicatorName

Type

| Count Road-Stream Crossings. Sth Order...

sys

|—|

QU Count Road-Stream Crossings. 1^-3rd Or..

sys

I Count Road-Stream Crossings. 4th-9th 0...

sys

I I •/ i u n—U *- IA/C /in

IndicatorName

Type

X of HUC12 Instate (AL)

sys

1X of HUC12 Instate (AR)

sys

X of HUC12 Instate (AZ)

sys

I I

_z.

Indicator

Weight

Type

Soil Stability. Mean in WS

Ecological

% Wetlands in HCZ (2011)

Ecological

% N-lndex1 in HAZ {2011)

Ecological

% Forest in WS (2011)

Ecological

Count Road-Stream Crossings. 1st-3rd Order (2015)

Stressor

X Imperviousness, Median in WS (2011)

Stressor

X Human Use. U-lndex1 in HCZ (2011)

Stressor

% Developed, Medium Intensity in RZ(2011)

Stressor

% Urban Change in WS (2001-11)

Stressor

X Urban in WS (2011)

Stressor

% Waterbody Area with Sediment TMDLs (2015)

Social

NPDES Permit Count

Social

Drinking Water Source Protection Area, Total

Social

Drinking Water Source Protection Area, Cumulative

Social

X GAP Status 1 and 2

Social

%of HUC12 Instate (AL)

Social

Slope. Standard Deviation in WS

Standard deviation of slope in the HUC12 fin degrees). Source data was the NHDPIus2 National
Elevation Dataset (NED) Snapshot. (See also NED Snapshot glossary definition).

J Ready...

Untitled.wsio: 1484 features selected

-------
1. Indicator selection helpful hints

a) Indicator definitions

When your mouse hovers over an indicator on the left, the definition will
appear in the lower right box. A list of all indicators and their definitions can
also be found on the WSIO website.

bJ To select multiple indicators
CTRL-left click together on each indicator.

c)	To remove indicators from selection

Find the indicator to be removed from selection in the tables on the left; then
using CTRL-left click together, click on the indicator to remove it from the right
'Selected Indicators' box.

d)	To remove all indicators from a category selection

There is a 'CLEAR SELECTION' button under each indicator category grouping.
Click this, and all indicators that have been selected will be removed.

e)	Using a 'Neutral Variable'

The last indicator in each list is called a 'neutral variable.' Use this when you do
not wish to select any indicators in a certain category. A category that uses the
neutral variable indicator will not have influence on the WSI Score.

f)	Applying a weight factor

You can also apply a weight factor to indicators within the table to the right.
Weights assigned to each indicator are set to one (1) automatically, but they
may be changed by the user simply by typing a new weight value to replace it.
Typical weights range from 0.5 to 3, with higher weight values giving the
indicator more influence on the final Index score, and lower weight values
making the indicator have less influence. It is recommended that the user
perform an initial screening run with the weights set to their default values for
each indicator, and only increase or decrease the weights with valid reason.
Statistical correlation analysis may provide a basis for showing which indicators
are - or are not - correlated with each other, and which indicators have the
strongest relationship to the health of the watershed.

15

-------
WSIO Screening Results

A. Indicator Data

The 'Selected Indicator Data' tab is now enabled and shows indicator data (upper left box), summary
statistics (lower left box) and a graph of the indicator data (right side). This information is displayed
here so you can familiarize yourself with the data that has been pulled into your project. Users can
select from the dropdown list above the graph to select an indicator to plot (HINT: highlight the list
then use mouse wheel to scroll). You can also change the graph type between 'Series' and
'Probability' in the dropdown under the graph. The Series option, will graph the HUC on the x-axis
and the indicator value on the y-axis (upper left table). The Probability option, will graph the lower
left table where the probability is on the x-axis and the value of the indicator is on the y-axis.

Next, click on the 'Indicator Correlations' button (located in the lower, middle of the window).

B. Run Indicator Correlations
This is an optional, but important step that has been provided to help in the selection of Ecological
and Stressor indicators. The tables provided on the left are separated by indicator type. They
provide correlation information on all the indicators you have selected. Click on a row to see the
data graphed. You can use this information to see, for example, if two indicators are highly
correlated or not; and then decide if both are needed in your WSIO project. The selection of
indicators should be a very thoughtful process, and will likely require some trial and error.

-------
1.	Change your indicator selection

Return to the 'Watershed Indicators' tab and change the indicator selections that are
highlighted. Only selected indicators will be included in the WSIO screening and
calculations. Click on 'WSIO Screening.'

2.	Change your HUC selection

Return to the 'Map' tab and change the HUC selections that are highlighted either by
selecting them directly on the map or using the attribute table. Only selected HUCs will
be included in the WSIO screening and calculations. Return to the 'Watershed
Indicators' tab and make any indicator adjustments, then click 'WSIO Screening.'

Correlation Analysis



~ick on row to plot correlations.





Correlation



Ecological Indicators Correlation

% Urban in WS (2011)

8 S 8 55 8

• ¦

• ¦

• • • •

• ¦

• • •

1

¦ m
m

" A
! - . '

. Ts .

¦jV1
*





Ecological:1 Ecological :2 Spearman_rho pValue_rho Pearson_cor pValue_cor

*





% National Ecolo...

X Forest Change ...

-0.274

<0001

-0.269

<0.001

=

X National Ecolo...

% Forest in WS (...

0.548

<0.001

0.525

<0.001

Soil Stability. Me...

X N-lndex1 in HC...

0.111

<0.001

0.115

<0.001

Soil Stability. Me...

% Wetlands in W...

0.009

0.583

0.032

0.063

Soil Stability, Me...

X Forest Change...

-0.271

<0.001

-0.232

<0.001

Soil Stability, Me...

X Forest in WS (...

0.129

<0.001

0.093

<0.001

% N-lndex1 in H...

X Wetlands in W...

0.916

<0.001

0.910

<0.001

X N-lndex1 in H...

% Forest Change ...

-0.194

<0.001

-0.233

<0.001

% N-lndex1 in H...

% Forest in WS (...

-0.308

<0.001

-0.383

<0.001



~

v. Wetlands in W..

X Forest Change...

-0.131

<0.001

-0.139

<0.001





X Wetlands in W...

% Forest in WS (...

-0.481

<0.001

-0.522

<0.001

% Forest Change...

% Forest in WS (...

-0.108

<0.001

-0.028

0.107



-



Stressor Indicator Correlations







Stressor:! Stressor:2 Spearmanjbo pValuejho Pearson_cor pValue_cor

—





Population Densi...

X Imperviousnes...

0.847

<0.001

0.936

<0.001

Population Densi...

Empower Density...

0.553

<0.001

0.778

<0.001

Population Densi...

% Human Use, U...

0.525

<0.001

0.404

<0.001

Population Densi...

X Urban Corrtigu...

0.820

<0 001

0.938

<0.001

Population Densi...

Count Road-Stre...

0.099

<0.001

0.007

0.699

Population Densi...

Count Road-Stre...

0.414

<0.001

0.222

<0.001

Population Densi...

Length All Roads...

0.550

<0.001

0.618

<0.001

Population Densi...

% Developed. Hi...

0.760

<0.001

0.851

<0.001

Population Densi...

% Urban in HCZ(...

0.651

<0.001

0.827

<0.001



~

Population Densi..

X Urban in WS (...

0.827

<0.001

0.930

<0.001





% Imperviousnes...

Empower Density...

0.658

<0.001

0.857

<0.001

F

c ft		 i i i i i i ¦ i ¦ i i ¦ i ¦

X Imperviousnes...

X Human Use, U...

0.575

<0.001

0.439

<0001

X Imperviousnes...

X Urban Contigu...

0.907

<0.001

0.961

<0.001

1 OK 1

Population Density in WS

"





17

-------
V. WSIO Screening Results

The WSIO Tool will automatically calculate Ecological Index, Stressor Index, Social Index and combined
Watershed Index (WSI) scores for each HUC12 analyzed as part of the screening calculations. These
results may be examined as a table, map, or bubble plot within the WSIO Tool, or exported for use in
other software. The values for individual watershed indicators included in a screening run may also
be viewed in a table or map.

Looking at the 'WSIO Scores' tab, the 'WSIO Data Graph' on the right displays the Ecological Scores and
the Stressor Scores for the set of HUC12s selected and allows users to visualize the relative influence of
the ecological, stressor and social index factors in each watershed. WSIO uses a min-max normalized
scoring for each indicator. Normalization using the minimum and maximum value of the indicator is
equivalent to the assumption of an empirical uniform distribution. A three-dimensional plot displays
screening results as waters plotted relative to X (Stressor Index), and Y (Ecological Index), with the dot
size varying by Social Index score. Click on 'Show Normalized Scores,' in the lower left, to display the
summary Indicator Scores in the grid.

WSIO-C:\Users\rpolinsk\Documents\WQPB\WSIO\WSIOvl_DS19071917\data\llntitled.wsio
Project About

: [None llOO T| '¦ c ¦ :+ ' ¦' ~ "i ¦ O

Map | Watershed Indicators Selected Indicator Data

HUC12 wsravm Shrub/Scrub Grassland/Herbace yyc'r
l ' in WS (2011) in WS (2011) {

031501060101

0.5335

0.3243

0.5276

0.0040

060300010201

0.5163

0.2626

0.4521

0.0778

060300010202

0.4778

0.6894

0.7374

0.0461

060300010203

0.5721

0.5641

0.6730

0.1228

060300010204

0.6666

0.4701

0.5649

0.0943

060300010205

0.3837

0.2708

0.8255

0.4722

060300010302

0.8257

0.4630

0.4598

0.0216

060300010303

0.9680

0.0626

0.1208

0.0030

060300010304

0.7651

0.0983

0.3848

0.4407

060300010305

0.9134

0.1574

0.2174

0.0171

060300010306

0.9228

0.1853

0.2617

0.0462

060300010307

0.4438

0.3084

0.4404

0.5311

060300010401

0.4107

0.4802

0.6359

0.0335

060300010402

0.5493

1.0000

0.0946

060300010403

0.6068

0.8305

0.6214

0.1106

060300010404

0.6867

0.2639

0.5561

0.2564

060300010405

0.4272

0.3038

0.3596

0.5924

060300010406

0.3009

0.3910

0.4074

0.0379

060300010407

0.4224

0.5337

0.4159

0.0643

rwyyinnniainfi

naivi

n?iGi

n-^HR

n •vav?

Show Normalized Score

Ecological vs Stressor Scores

-Qo-

o
-------
A, WSIO Scores page helpful hints

All of the watershed indicator values are normalized to have a maximum value of 1.0.

For the Ecological and Social Index values, higher index scores imply a higher probability that the
watershed will support ecological services and higher probability that the social setting is favorable to
action, respectively.

For the Stressor Index, a lower score implies that there are fewer stressors driving negative change in the
watershed.

For the combined WSI score, higher scores imply a higher likelihood that conditions are favorable to the
user's objectives.

It is important to understand that small differences in index scores are probably not important. However,
the index scores provide a simple, easy to understand way to compare the relative condition of a group of
screened waters, and to organize them from higher to lower likelihood of meeting users objectives based
on their scores. The summary information provided on the WSIO Scores tab makes it easy to look at the
range of scores, and to see whether any of the screened watersheds had especially high or low scores for
any of the indices or individual indicators.

This information may be used to group rank-orders into classes- typically by quartile- or to select a specific
number or percentage of the watersheds for further investigation. Results may be sorted to parse and
view data in a variety of ways.

1. Clicking the mouse curser on a bubble will show information about that watershed under the
graph, including its name and 12-digit HUC ID, the calculated Ecological, Stressor, and Social
Index scores, as well as the Watershed Index Score.

2. The upper left quadrant would contain waters that have high ecological and low stressor scores.

3. Waters in the upper right quadrant have high ecological and stressor scores.

4. Waters in the lower left quadrant will have lower stressor index scores, but also low ecological
index scores.

5. The lower right quadrant shows watersheds with high stressor and low ecological scores.

6. Larger dot sizes indicate better social scores based on the indicators chosen.

-------
7. You can right-click the WSIO Scores Graph and select 'Copy,' then copy the image to another
document.

Map Indicator Scores

Click on the 'Map' tab to display a thematic map of indicator scores. This map provides a way to
visualize indicator data and screening results to better understand any geographic factors that may
be influencing index scores. Select from the Map Basin Metrics dropdown list located at the top of
the map to select an indicator or score to map. See below for some map symbology and use hints.

1° la-bay

a-1 WSIO-E:\wsioapp\data\Untitled.wsio

-------
1. Map symbology hints

a) Change Map Symbology

Right click on the HUC layer in the legend and select 'Properties.' The 'Layer
Properties' window will open allowing you to make changes to the map
symbology.

WSIO-E:\wsioapp\data\Untitled.wsio

Project About

Ea a : § :§§]©> u €>

Map Watershed Indicators Selected Indicator Data j WSIO Scores

Legend | Tools

B ^ Map Layers

B IZl 1484HUC12s_lf
BWSI

¦ 0.873
B IS Untitled .wsio
~

B El WSfOHUCSsm

B G3 state

b) Layer Properties Window

1. Field In this dropdown, choose the indicator or score you would like to
symbolize.

2. Change HUC symbology color Use the 'Hue Range' to change the color
gradient of the scores. Move the sliders for a smaller range of colors.
Click 'Apply.'

3. Adjust data interval groupings Under Statistics, change the Interval Snap
to 'none/ This will populate the Values and Legend Text columns in the
table as a range of values.

4. Change the Results Categories Under Statistics, change the 'Num
Breaks' value to change the number of results categories. You can view
these breaks by clicking on the 'Graph' tab.

5. Click 'Apply' when complete.

-------
Layer Properties

V £3

Symbology Detailed Property

HSL RGB

Saturation Range:

IH Use Gradients

.Angle:

Quantities

Reld: WSI

Values

Legend Text

Statistics Graph

Normalization Reld:
Interval Method:

Equal Interval

Interval Snap:

None

Exclude Members

Num Breaks:

ooalll)

Count

<=0.32222

0.32222-0.44734

0.44734-0.57246

0.57246 - 0.S3758

0.57246 -0.63753

> 0.63755

:> 0.69750

Count

184

Hin

Max

Sum

115

Mean

Median

Std

Cancel

Apply

C. View Watershed Index Scores and Indicator Values for each HLJC12 watershed

The WSIO Scores tab contains the table of Ecological, Stressor, Social indicator values, and combined
Watershed Index (WSI) Scores for each watershed included in the screening run. This table is a great
reference to see the values that went into the calculation of WSI Scores. Users can select all the data
within the table (use the SHIFT key to select all values between the first and last entry) then copy (CTRL-
C) and paste (CRTL-V) it into other software for further filtering and analysis. (HINT: by highlighting and
copying all entries into and Excel worksheet, the header row will paste with the data)

-------
VI. Open an Existing Project

Run the WSIO.exe (See Section 1). The application will open with the option to use a 'Web Service'
or a 'Local Geodatabase' to pull in indicators to the tool. Make a choice, then click 'OK.' In the
'Project' window, select 'Open.' Navigate to your saved project (the default will place your project
in the 'Data' folder of your application folder). Open the yourprojectname.\NS\0 file. This file will
contain the geography and indicators that were selected and saved.

A. Save-As

Save-as your project with a new name to be able to compare results to another WSIO
screening run. Click on 'Project' in the upper left navigation menu and select 'Save As.'

Bu WSIO

Project | Select HUCs
New

Download WSIO Indicators Indicator Correlations WSIO Screening About
H 0 ® B O i # H |i None • 100

Open

Save Ctrl+S
Save As
Build User DB
Exit

|" Ready.

-------
VII. Build a User Database of Indicators

The WSIO Tool allows a user to bring in indicators of their own. These may be region or state
specific indicators, for example, that have been identified and calculated for a specific area. In order
to incorporate these regional specific indicators, the information about them needs to be put into
the WSIO Tool as described in this section. A template has been created and provided for this
purpose. Refer to the excel template (sample-userdata.xlsx) that is located in the 'Data' folder of
the application package. There are two tabs that must be filled out completely - 'user_indicator'
(this is requesting information on each indicator) and 'user_indicator data' (this is requesting
indicator data for each HUC12). Once complete, this file can be imported into your project.

File

Home

Insert Page Layout

ormulas Data Review

sample-userdata.xlsx - Excel
View Developer

Smith, Elizabeth H —

0 Tell me what you want to do

~ X

Q. Share

SdJ-

Paste

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Calibri '|ll '] A* a"
B I u ~ 1 ^ ~

Font ft

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* 70 T .00 -».o

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Cells

Sort & Find &
v " Filter' Select'
Editing

D14

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User Indicators

NUMBER OF USER INDICATORS
INDICATORFIELD

INDICATORNAME

TYPE

DESCRIPTION

WETLAN DS_N LCD_PCT_WS

% Wetlands (2006) in Watershed

Ecological

Percent Wetlands (2006) in Watershed

FOREST_NLCD_l

PCT_WS

% Forest (2006) in Watershed

Ecological

Percent Forest (2006) in Watershed

UJNDEX

NLCD

_PCT_WS

% Fluman Use, U-index (2006) in Watershed

Stressor

Percent Fluman Use index (2006) in Watershed

AG_NLCD

_PCT_WS

% Agriculture (2006) in Watershed

Stressor

Percent Agriculture (2006) in Watershed

14]

Ready ?

userjndicator | userjndicatordata | (+)

HUE] 1 + ioo%

Within the application, click on 'Project', then 'Build User DB.' In the new window that opens, click on
'Import' and navigate to your Excel file.

-------
WSIO-C:\Users\EMCGUIRE\Desktop\Tools\WS10vl-05101Adata\Untitled.wsio^

Project Select HUCs

Download WS10 Indicators Indicator Correlations WSIO Screening About

New

E-2 ^ Q, O 0 <§> [ ( None " 100 *

Open

Save Ctrl+S

Save As

Build User DB

Exit

b1j

Build User Indicator Database

User Indicator File:

1 Import

User Indicators

User Data

-------
User imported indicators will be located at the end of the indicator list and identified in the type column
as 'usr.'

Ecological Indicators

IndicatorName

Type

% Rare Ecosystem in WS

sys

Neutral Variable, Ecological Category

sys

% Wetlands (2DDG) in Watershed

usr

% Forest (2O0G) in Watershed usr

dear Selection

Refer back to Section 3 for instructions on how to build a project.

For additional information please refer to the WSIO webpage and user manual available here:
https://www.epa.gov/wsio.

-------
VIII. References

EPA Science Advisory Board (SAB), 2002. A Framework for Assessing and Reporting on Ecological
Condition (EPA-SAB-EPC-02-009).

Moore, I. D., Grayson, R. B., and Ladson, A. R., 1991, Digital terrain modelling: A review
of hydrological, geomorphological and biological applications. Hydrological Processes,

5, 3± 30.

Norton, DJ et al (2009). A method for comparative analysis of recovery potential in impaired waters
restoration planning. Environmental Management 44:356-368. DOI 10.1007/s00267-009-9304-x.

http://www.springerlink.com/content/d51523tq8784643k/

USEPA, 2011. Fact Sheet: Recovery Potential Project - Landscape Screening Tools and Resources for
Comparing the Restorability of Impaired Waters. U.S. Environmental Protection Agency, Office of Water,
Washington, D.C. EPA-841-F-11-002, March 2011.

Wollock, D.M., 1993. Simulating the variable-source-area concept of streamflow generation with the
watershed model TOPMODEL: U.S. Geological Survey Water-Resources Investigations Report, 93-4124,
33 p.

-------
IX. Glossary
Catseed:

Raster hydrology data. See: National Hydrography Dataset CatSeed.

Ecological Index (Ecological Index Score):

A value calculated to reflect the overall condition and capacity of the watershed to provide
ecological services, based on metrics related to natural watershed processes and structure.

Ecological Indicator:

One of the classes of watershed indicators used in the WSIO. Ecological Indicators are
measurable characteristics of a watershed related to the structure, composition, or function of
its ecological systems. Examples include the number of aquatic species, percent natural cover,
mean elevation, and mean slope of a watershed.

Ecoregion:

Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and
quantity of environmental resources. They are designed to serve as a spatial framework for the
research, assessment, management, and monitoring of ecosystems and ecosystem components.
By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions
stratify the environment by its probable response to disturbance. These general purpose regions
are critical for structuring and implementing ecosystem management strategies across federal
agencies, state agencies, and nongovernment organizations that are responsible for different
types of resources within the same geographical areas.

Empower Density:

Empower density is the flow of emergy released per unit time by a unit volume. Emergy is the
available energy of one kind previously used up directly and indirectly to make a product or
service.

EnviroAtlas:

Ecosystems, such as forests and wetlands, provide many essential benefits, including clean air
and water, food, fiber, and recreational opportunities. These and other benefits from nature,
referred to as "ecosystem services," are multifaceted, often intertwined, and can be difficult to
quantify because of their complexity. Due to this complexity and a lack of information, planning
efforts often discount or overlook the impacts of decisions on the full suite of ecosystem
services. To help fill this information gap, the EPA and its partners researched effective ways to
measure and communicate the type, quality, and extent of services that humans receive from
ecosystems so that their true value can be considered in decision-making. These research efforts
and data are incorporated into the EnviroAtlas, a web-based tool that combines maps, analysis
tools, and interpretive information on ecosystem services. Data are provided for subwatersheds

-------
across the contiguous United States and at a higher resolution for selected communities. More
information can be found here: http://enviroatlas.epa.gov/enviroatlas/atlas.html

Healthy Watershed Initiative

EPA created the Healthy Watersheds Program to proactively protect aquatic ecosystems as
dynamic systems across landscapes in order to maintain the natural structure and function of
ecosystems as intended by Congress in the 1972 Federal Water Pollution Control Act
amendments. This systems approach protects aquatic biota and their habitat as well as
watershed characteristics and processes that support them such as vegetative riparian corridors
and headwaters, hydrology, geomorphology, and natural disturbance regimes. The holistic
protection approach provided by the Healthy Watersheds Program is essential for addressing
the pervasive threats to healthy watersheds, including loss and fragmentation of habitat,
hydrologic alteration, invasive species, and climate change. More information can be found
here: http://water.epa.gov/polwaste/nps/watershed/index.cfm

HUC (Hydrologic Unit Code):

HUC is an acronym for Hydrologic Unit Codes, which is a numeric system for uniquely identifying
all of the drainage basins in the United States. HUCs represent multiple, hierarchical levels of
nested geographic units, from the largest unit (Hydrologic Region), to the smallest (Subbasin).
The scale of the watershed can be determined by the number of digits in the HUC, such that
smaller watershed scales have more digits in their codes, representing additional sub-divisions.
The United States has been divided into 21 Hydrologic Regions, which are further divided into
221 Subregions. The Subregions are divided into Basins, and then Subbasins. Many geographic
datasets use six levels, resulting in 12-digit HUCs. A 12-digit HUC indicates the hydrologic Region
(first two digits), hydrologic Subregion (second two digits), Basin (third two digits), Subbasin
(fourth two digits), Watershed (five two digits), and Subwatershed (last two digits).

HUC8:

One level in a hierarchically nested series of surface drainage-based geographic units identified
by their Hydrologic Unit Codes (HUC) and the number of digits in that level's identifier (in this
case, eight). HUC8s may be referred to as Subbasins, or sometimes Cataloging Units. A typical
HUC8 Subbasin is around 700 square miles.

HUC12:

One level in a hierarchically nested series of surface drainage-based geographic units identified
by their Hydrologic Unit Codes (HUC) and the number of digits in that level's identifier (in this
case 12). HUC12s average roughly 40 square miles in area, and there are about 83,000 HUC12s
covering the lower 48 states. Together, the geospatial data on the several levels of HUCs
comprise the Watershed Boundary Dataset (WBD). As the WBD is frequently modified through
mapping updates, a "WBD snapshot" was benchmarked and integrated with the National
Hydrography Dataset's most recent major update (see National Hydrography Dataset Plus
Version 2). Although the terms "watershed" and "HUC" are often used synonymously, HUCs may
be either a true watershed or a drainage-defined portion of a larger watershed that includes

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many HUCs. Multiple HUC levels have been used in RPS and WSI projects, but the WSIO
indicator data are all compiled at HUC12 scale.

Hydrologically Connected Zone:

This term is used to describe indicators that are measured only within a specified part of the
HUC12 - in this case, only the HUC12 areas that have a compound topographic index score
greater than 550 and are contiguous to the Water Mask. The naming convention for these
indicators includes the abbreviation "HCZ." For example, the Hydrologically Connected Zone
percent urban land cover in the HUC12 is calculated by first measuring the urban area in the
HUC12 only within the HCZ as defined above, and then dividing by the total area of the HIJC12
(including all land and water). Because the HCZ is based on a topographic index rather than as a
zone of assigned proximity to waters mapped at 1:100,000 scale, it sometimes can differ
substantially from the RZ -- such as when river floodplains far exceed the RZ's standard 100
meters-per-side width, or when moist HCZ areas occur along small tributaries not mapped at
1:100,000 scale (see also Riparian Zone).

Hydrologicaiiy-Connected Zone

Indicator(s) (and Indicator Type):

As used in the WSIO, an attribute of a watershed that is useful for watershed comparison and
can be consistently measured throughout the geographic area of interest. Most of the WSIO's
several hundred indicators are derived from geospatial data analysis, although some come from
field monitoring and other information sources that have been geospatially referenced to
watersheds. Indicators in the WSIO data table are grouped by Indicator Type into Ecological,

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Stressor, Social, or Base (i.e. value-neutral) classes that make up the primary data used in
watershed comparisons. See also: Base Indicator, Ecological Indicator, Stressor Indicator, and
Social Indicator.

N-lndex:

An index of natural cover, not urban or agricultural, by the NLCD. N-index Land cover
classifications include 'Barren Land (Rock/Sand/Clay)' (code 31), 'Deciduous Forrest' (code 41),
'Evergreen Forest' (code 42), 'Mixed Forest' (code 43), 'Shrub/Scrub' (code 52),
'Grassland/Herbaceous' (code 71), ' Woody Wetlands' (code 90), and 'Emergent Herbaceous
Wetlands' (code 95). N-index is consistent with the Analytical Tools Interface for Landscape
Assessments (ATtlLA) version 2004. ATtlLA user guide can be found here:
http://www.epa.gov/esd/land-sci/attila/pdf/user guide.pdf.

N-index 2:

A modified N-index of natural cover (excludes barren, urban or agricultural classifications). N-
index 2 cover classifications include 'Deciduous Forrest' (code 41), 'Evergreen Forest' (code 42),
'Mixed Forest' (code 43), 'Shrub/Scrub' (code 52), 'Grassland/Herbaceous' (code 71),' Woody
Wetlands' (code 90), and 'Emergent Herbaceous Wetlands' (code 95) by the 2006 National Land
Cover Database. N-index 2 was modified from the Analytical Tools Interface for Landscape
Assessments (ATtlLA) version 2004. ATtlLA user guide can be found here:
http://www.epa.gov/esd/land-sci/attila/pdf/user guide.pdf.

National Ecological Framework:

The National Ecological Framework (NEF) is a GIS based model of the connectivity of natural
landscapes in the lower 48 United States. It was developed to provide a guide for the protection
of the natural ecosystem processes that give us clean air, pure water and protected lands that
are part of EPA's mission to protect. The purpose was to develop a mapped data set of
ecologically important areas that could be connected with a hub/corridor model. See EPA's
Geoplatform.

National Hydrography Dataset CatSeed:

Raster data of the flowline and waterbody features only from the National Hydrography Dataset
(NHD) Plus version 2.

National Hydrography Dataset Plus Version 2:

The current standard for EPA and many other users of nationally consistent geospatial data on
surface waters at 1:100,000 scale. NHDplus2 represents the most recent major update of
national surface waters mapping (the NHD), but in addition contains several value-added
attributes on other environmental parameters. Further, NHDplus2 was integrated with the
Watershed Boundary Dataset (WBD) snapshot to benchmark a standard, watershed and surface
waters dataset at a specific point in time (see also HUC12).

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National Land Cover Database:

Serves as the definitive Landsat-based, 30-meter resolution, land cover database for the Nation.
NLCD provides spatial reference and descriptive data for characteristics of the land surface such
as thematic class (for example, urban, agriculture, and forest), percent impervious surface, and
percent tree canopy cover. Multiple years are available at about 5 year intervals.

Recovery Potential Screening:

A watershed comparative assessment method using ecological, stressor, and social indicators in
each watershed to compare restorability differences among the watersheds and set priorities
for action. The Recovery Potential Screening (RPS) tool is a customized Excel workbook that
houses all the watershed indicator data and auto-calculates four RPS indices, displaying the
watershed comparison results as rank-ordered tables, graphics, and maps. Users can select the
watersheds to be screened, indicators and their weights, and customize the graphic and map
outputs as well as save the latter as images for later use. As of 2014, the RPS data from the
WSIO and statewide RPS tools cover the entire lower 48 states at the HUC12 and HUC8
watershed scales (tools for remaining states and territories are planned), and over 20 states
have applied the RPS tool in watershed screenings for a variety of purposes since 2005.

Riparian Zone:

This term is used to describe indicators that are measured only within a specified part of the
HUC12 - in this case, within only the HUC12 lands that occur within 100 meters of the Water
Mask; then summed to provide one total value for the HUC12. The naming convention for these
indicators includes the abbreviation 'RZ.' For example, the Riparian Zone percent urban land
cover in the HUC12 is calculated by first measuring the urban area in the HUC12 only in the
riparian zones as defined above, and then dividing by the total area of the HUC12 (including all
land and water). As a standard-width measurement generalized to include shorelands for any
size or type of water body, the RZ may be wider than floodplains of small streams and narrower
than floodplains of larger rivers (see also Hydrologically Connected Zone).

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Social Index (or Social Index Score):

A value calculated to account for social factors, such as community involvement, incentives,
economics, governance, regulation, and planning status that, while not directly reflective of
watershed condition, often strongly influence the level of effort and complexity of making
improvements in a given watershed.

Social Indicator:

One of the classes of watershed indicators used in the WSIO. Social Indicators are metrics of
socially-related parameters that may affect prospects for success of restoration or protection
efforts. Examples include measures related to TMDLs, NPDES permit counts, drinking water
sources, and size of natural areas, etc.

Stressor Index (or Stressor Index Score):

A value calculated to reflect the pressures (drivers of change) on watershed condition from
several primary sources of pollutants and water quality impairments.

Stressor Indicator:

One of the classes of watershed indicators used in the WSIO. Stressor Indicators relate to
pressures on the watershed from either natural or anthropogenic sources, such as watershed-
or corridor-level disturbances, hydrologic alteration, and measures of pollutant emissions, etc.

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Examples include the percent imperviousness, road density, and the percentage of agriculture in
a watershed.

U-lndex:

An index of urban and human disturbed land-uses, including agricultural or urban classifications
by the NLCD. U-index Land cover classifications include 'Developed, Open Space' (code 21),
'Developed, Low Intensity' (code 22), 'Developed, Medium Intensity' (code 23), 'Developed, High
Intensity' (code 24), 'Pasture/Hay' (code 81), and 'Cultivated Crops' (code 82) by the 2006
National Land Cover Database. U-index is consistent with the Analytical Tools Interface for
Landscape Assessments (ATtlLA) version 2004. ATtlLA user guide can be found here:
http://www.epa.gov/esd/land-sci/attila/pdf/user guide.pdf.

U-lndex 2:

A modified U-index of urban and human disturbed land-uses that includes barren, agricultural
and urban land-uses. U-index 2 cover classifications include 'Developed, Open Space' (code 21),
'Developed, Low Intensity' (code 22), 'Developed, Medium Intensity' (code 23), 'Developed, High
Intensity' (code 24), 'Barren Land (Rock/Sand/Clay)' (code 31), 'Pasture/Hay' (code 81), and
'Cultivated Crops' (code 82) by the 2006 National Land Cover Database. U-index 2 was modified
from the Analytical Tools Interface for Landscape Assessments (ATtlLA) version 2004. ATtlLA
user guide can be found here: http://www.epa.gov/esd/land-sci/attila/pdf/user guide.pdf.

Water Mask:

Represents all surface waters, including lakes, rivers, streams, wetlands, estuaries, and
nearshore ocean waters, as mapped in the 1:100,000-scale National Land Cover Database
(NLCD) and National Hydrography Dataset (NHD). Surface water features from the 2006 NLCD
included are 'Open Water' (code 11), 'Woody Wetlands' (code 90) and 'Emergent Herbaceous
Wetlands' (code 95). Flowline and waterbody features included are consistent with the catseed
grid from the NHD Plus version 2. In developing the WSIO, the Water Mask was a geospatial
dataset specially produced for use in measuring many of the indicators in terms of their
proximity to surface waters (see also Riparian Zone and Hydrologically Connected Zone).

Watershed:

This term is used to describe indicators that are measured throughout the entire geographic
area of the HUC12; the naming convention for these indicators includes the abbreviation 'WS.'
For example, the watershed percent urban land cover is calculated by measuring the total
urban area in the HUC12 and dividing by the total area of the HUC12 (including all land and
water). Although all indicators in the WSIO are expressed as attributes of HUC12s, many
indicators (such as Riparian Zone metrics) are measurements of only part of the HUC12 (e.g.,
only the riparian zones throughout the HUC12). Note that the use of this term in an indicator
name implies measurement within the HUC12 only and does not imply that the indicator value
was calculated cumulatively from the entire watershed (e.g., full drainage basin above the
HUC12) unless specifically noted.

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Watershed Index (Watershed Index Score):

A value calculated from the combined effects of the Ecological, Stressor and Social Index values
to reflect the overall condition of a watershed. The Watershed Index is calculated as:

Ecological + Social + (100 — Stressor)

Watershed Index =

Watershed Index Online:

The Watershed Index Online (WSIO) project was initiated in 2008 to improve ways to compare,
prioritize and target watersheds for a broad range of watershed management purposes on local,
state, regional, and national scales. Developed to assist federal, state, and local partners in
prioritizing activities based on watershed condition and suitability or need for protection,
restoration, improved monitoring, and other management activities. The goal of the WSIO is to
increase the capacity for states and others to perform comparative watershed analysis by
providing a library of hundreds of the most popular watershed indicators, already processed and
compiled for roughly 83,000 12-digit Hydrologic Unit Code (HUC12) watersheds throughout the
contiguous United States. These attributes have been measured consistently at a small
watershed scale (e.g., 40-square mile average size - see HUC12.) The WSIO Tool allows users to
easily download uniformly measured watershed indicators for a defined project area, to
generate comparative rankings for those watersheds and sub-watersheds based on ecological,
stressor, and social context indicators selected by the user, and to save a variety of watershed
comparative screenings for further analysis or export of tables, maps, and plots.

Wetness Index:

The wetness index, also known as the compound topographic index (CTI), is a steady state
wetness index. It was derived from the NHDPIus flow accumulation and slope of the Digital
Elevation Model (DEM) to represent topographic areas that are typically wet. The Wetness
Index used for the WSIO tool was created using the following equation:

grid wet_ndx = 100*(ln (flow accumulation/tan(slope)) + 3x3 mean of In (flow
accumulation/tan(slope))/2

The values were not scaled by an area factor and were smoothed by Vz to make up for some
inconsistencies across the national DEM, because of differences in the resolution of the DEM by
USGS quad sheet. The data were then compared to the 2001 NLCD wetland classes, Region 4
FEMA flood zone classes, and Georgia National Wetlands classes. The threshold for value of
800, of the wetness index, represents areas which are usually wet. This was primarily based on
the 2001 NLCD comparison, but also supported by the other analyses (Moore, 1991 and
Wollock, 1993). The wetness index, tends to overestimate wet areas, in part because it does not
consider precipitation and evaporation water balances. It will also overestimate wetness in
areas with highly permeable soils that do not retain water. Finally, CTI indicates wet areas based
entirely on topography and surface water flow and will miss wet areas created by other factors
such as heavy precipitation or irrigation outflow.

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