Benefits of enhanced geospatial water data

National Hydrography Requirements and Benefits Study
Benefits and Examples
1. Methods for estimating financial and other tangible benefits
For USGS’s prior National Enhanced Elevation Assessment (NEEA), USGS documented the range of cost
benefits that would result from enhanced elevation data and justified expanded budgets for the current
3D Elevation Program (3DEP) without adversely impacting the budgets of those agencies that indicated
they would receive major time/cost savings as well as improved operational benefits and customer
service benefits from enhanced elevation data they considered to be mission critical.
Similarly, for this National Hydrography Requirements and Benefits Study, we need questionnaire
responders to translate their intangible benefits into tangible benefits such as the following for each of
your Mission Critical Activities. Questionnaire responders should think in terms of tangible benefits that
yield cost benefits in any or all of the following categories.
For activities you consider to be mission critical, using hydrography data currently available or enhanced
hydrography data that you might receive in the future, please consider the following:
1.1. Operational Benefits:
Operational benefits may fall into several categories including direct dollar savings from reduced
data acquisition; reduced labor costs; annual savings or percent improvement in operational
efficiency or effectiveness; or improvements to mission critical programs through improved
modeling, analysis, or planning. Examples may include:
Data Acquisition
Reduced data acquisition costs
Work hour savings by having readily available enhanced hydrography data in all areas of interest
Work hour savings by having authoritative data readily available and not having to search for
the best available data
• Reduced possibility of errors resulting from use of disparate datasets
Labor Savings
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Reduced labor costs on design and construction of new projects
Reduced labor costs by having stakeholders perform some of their own analyses
Reduction in time necessary for analysts to execute mission critical tasks
Reduced labor and travel costs by being able to perform tasks in the office and not having to
collect field data for your modeling/analyses or perform field inspections
• Costs avoided by not having to perform tasks that you previously performed
Operational Improvements
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Improved operational efficiency in performing your Mission Critical Activity
Improved operational effectiveness:
o Perhaps satisfying compliance requirements where you are currently in non-compliance
o Perhaps providing customer service benefits that you previously could not provide
o Perhaps by modeling of stormwater as well as point source and nonpoint source
pollution of water and environmental cleanup of rivers and streams, wetlands, beaches,
etc.

Improved Modeling, Analysis, Planning
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Higher-accuracy and/or higher-resolution hydrography data to make computer models more
effective
Automated hydrologic or hydraulic modeling, for example, compared with field surveys
More reliably deliver natural resource enhancement benefits thereby focusing more funding on
nonstructural hydrologic restoration rather than water treatment and flood control
More reliably delineate restorable and existing wetlands over traditional mapping approaches
More efficient engineering plans/designs for restoration of watersheds, stream banks, wetlands,
forests, grasslands, dams, infrastructure, etc.

1.2. Customer Service Benefits:
Customer service benefits may be similar to operational benefits, but would be experienced by your
customers through using improved data or products that you deliver to them and that would
improve their ability to accomplish their mission. Examples may include:
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Availability of consistent, accurate and up-to-date down-loadable hydrography data nationwide,
compared with data that exists today
Ability to use accurate and authoritative hydrography data for pipeline routings or facility
sitings, for example
Reduced time necessary for their staff to execute their mission critical tasks
Improved operational efficiency in performing their tasks
Improved operational effectiveness in performing their mission critical tasks, perhaps satisfying
compliance requirements where they are currently in non-compliance
Estimated reduction in annual flood losses or crop losses as a result of enhanced hydrography
data
Annual savings for fish, shellfish and/or other industries

1.3. Societal Benefits:
Societal benefits may fall into categories such as improved education or public safety, protection of
the environment, or human lives saved. Examples may include:
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Savings to American taxpayers by using enhanced hydrography data for improved decision
making, e.g., to avoid natural or manmade disasters or having safer communities
Savings to communities by taking proactive steps to mitigate risks by informed siting of drinking
water, waste water, and other infrastructure facilities
Reduction in annual loss of life due to flooding or other hazards
Dollar benefits of restoration of watersheds, stream banks, wetlands, forests, grasslands, dams,
infrastructure, etc.

2. Example Operational Benefits
2.1. Prioritizing Stormwater BMPs
In response to numerous flood events within the Upper Delaware Basin of New York, which threaten
New York City’s municipal water supply watersheds, a coalition of researchers and officials
investigated water quality and flood management strategies which utilized ecosystem services. The
study relied on analyses which featured NHDPlus along with the National Wetlands Inventory.
Researchers then made a case for selecting conservation design-based stormwater best
management practices (BMPs) through cost benefit analyses by computing the replacement value
of, e.g., the stormwater detention naturally provided by the basin’s wetlands. The stormwater

BMPs were selected with reference to hydrologic, ecological, and urban growth indicators and
included a range of solutions, including restored wetlands and stream corridors, compact
development, and bioswales. The researchers propose that this framework for reducing the
incidence of flooding in urbanizing areas, while simultaneously preserving or improving a basin’s
water quality, could be replicated globally.
2.2. Streamlining Water Protection Analyses
The Environmental Protection Agency created a geospatial application, the Drinking Water Mapping
Application, to better serve the needs of staff and clients with respect to agency programs. The
NHDPlus dataset is used to represent surface waters and serves as the basis for
upstream/downstream and proximity analyses, which inform the identification and development of
Source Protection Areas. The tool is an important asset for program administration, streamlining the
process by which staff can obtain reports and maps across multiple program areas.
2.3. Improved Data Dissemination and Accessibility
Motivated by the desire to reduce the costs of data dissemination while also enhancing accessibility
to that data, the Environmental Protection Agency developed the Watershed Assessment, Tracking
& Environmental Results architecture. In this framework, databases for multiple programs are
indexed to the NHDPlus dataset. Consequently, program managers are able to investigate
relationships between agency programs as well as national and interstate water quality issues.
2.4. Cost Savings by Prioritizing Field Efforts
NHDPlus can be used in combination with numerous other datasets to facilitate visualization and
analysis. One example is a USGS study that included depiction of fish mercury concentrations
against the backdrop of perennial streams and mine locations, with stream line weights indicating
mean annual streamflow. This type of visualization is a powerful way to begin considering possible
relationships between mercury concentration and drainage patterns and may ultimately be useful
for prioritizing additional sampling locations and analyses.
2.5. Prioritization of Water Quality Issues
The Environmental Protection Agency developed the National Aquatic Resource Surveys with the
objective of creating a nationally-consistent estimate of the condition of our national aquatic
resources. The NHDPlus dataset was used to ensure representative sampling of different sizes and
classes of water bodies. NHDPlus, along with the Basin Delineator tool and the Catchment Attribute
Allocation and Accumulation Tool, was also used to parameterize drainage areas for surveyed water
bodies. The surveys identify potential influences on the nation’s water quality in terms of biological
condition, water quality and physical habitat, assisting in the determination of predominant
ecological stressors for a given water body. Results drive prioritization of national and regional
water quality issues, and the ability to track surveys over time will permit evaluation of the
effectiveness of water quality protection and restoration activities.
2.6. Maximizing Watershed Planning Resources
To address issues of water quality and water availability due to reservoir sedimentation, the Texas
Water Development Board commissioned a study to determine landscape and climate factors
contributing to sedimentation and to identify those reservoirs most at risk for sedimentation-related
impacts. NHDPlus was a significant source of the risk-related criteria developed to help prioritize atrisk reservoirs, which informed the output of the study’s decision-support tool. The tool also
includes a matrix of landscape-specific structural BMPs, providing excellent insight into potential
locations for BMP implementation. Information of this sort is highly valuable in today’s resource-

constrained environment, and can be used to inform watershed management plans, particularly
those with a sedimentation focus.
2.7 Better Focused Site Monitoring
In pursuit of the Environmental Protection Agency’s goal to focus site-monitoring efforts, an
analytical framework is being constructed using NHDPlus, the National Land Cover Database, the
National Elevation Database, U.S. Census data, and several other physical and administrative
variables. Using a network of 1,312 sample sites throughout the Pacific Northwest, the framework is
designed to support the modeling of stream health. The project’s initial focus was on nitrogen and
phosphorous, with the ultimate objective of building more complex models linking landscape
stressors to water quality.

3. Example Customer Service Benefits
3.1. Improved Access to Data and Reports
The Connecticut River Watershed Atlas leverages the NHDPlus dataset in combination with Google
Maps, Esri products, and other GIS web applications to provide users with the ability to create
queries, locate features, and explore data, including near real-time stream gage data. The
application provides access to information for approximately 12,500 stream segments. Outputs
include watershed delineation maps and summaries of spatial attributes. The Atlas is an innovative
format that substantially improves access to data and basic geospatial analysis capabilities to a
number of interested user groups.
3.2. New Value-Added Services
Many organizations and agencies accumulate significant resources that are available to users, and
innovative organization can substantially improve access to those resources. The Environmental
Protection Agency compiles GIS versions of the state 303(d) impaired waters and has developed a
geospatial dataset containing Total Maximum Daily Loads (TMDLs) for those waters. NHDPlus
thereby serves as the nationally consistent organizing framework against which impaired water data
is indexed. Further, EPA has created links between the TMDL ID attributes and related TMDL
documents. This unique setup facilitates efficient access to impaired waters information, mapped
waters with TMDLs, as well as TMDL documents.

4. Examples of Societal Benefits
4.1. Disaster Mitigation
U.S. Forest Service leadership prompted the development of the Incident Command Tool for
Drinking Water Protection, which is a GIS-based tool for modeling the origination and dispersion of
contaminants. Using the mean flow and velocity attributes for each reach in the NHDPlus dataset
along with real-time flow data, the GIS tool allows users to predict contaminant concentration at
drinking water intakes. This tool has also been incorporated into the Defense Threat Reduction
Agency’s Consequences Assessment Tool Suite and is an important tool for post-spill decisionmaking.
4.2. Saved Lives and Property
As part of the effort to develop alternative program standards for the Federal Emergency
Management Agency’s National Flood Insurance Program, the mapping, floodplain management,
and insurance components of the program were examined. One element of the analysis included
projecting future coastal and riverine Special Flood Hazard Areas nationwide and identification of

affected populations, landscape, and endangered species. The future riverine floodplain analysis
relied heavily on NHDPlus for drainage basin characteristics and the development of flow
accumulation information. The study has positive implications for the prospective adoption of
enhanced program standards to reduce the risk to human lives and property due to unsound
floodplain development and will also protect environmentally sensitive areas.
4.3. Improved Conservation Metrics and Education
Montana Fish, Wildlife and Parks created a seven-part, landscape-based classification system for
stream segments in the NHDPlus dataset. The resulting classifications were used to develop
ecosystem profiles, which were then analyzed against native aquatic biological samples. The
resulting analysis was used to prioritize catchments in western Montana according to maximum
conservation value with respect to preserving aquatic biodiversity. This information is also available
to help educate land managers about aquatic resources.
4.4. Improved Conservation Planning
Sensitive aquatic ecosystems at high elevations in the Rocky Mountains are vulnerable to
atmospheric nitrogen deposition. Atmospheric deposition of nitrogen was mapped against
estimated critical loads for nitrogen (i.e. the level below which ecological effects are thought not to
occur). Critical load estimates were informed by basin characteristics. The NHDPlus dataset
provided the organizing framework for the project’s models, which used the deposition and critical
load estimates to predict surface water nitrate concentrations in high-elevation areas across the
Rockies. This methodology is potentially replicable at other high-elevation locations globally and has
excellent potential for identifying vulnerable high-elevation aquatic ecosystems.