|
Geographic Information Systems (GIS) bring geographic measurements together
with powerful tools for visualization, analysis and modeling. These
technologies are being integrated into our planning and decision-making
processes.
In accordance with the
National
Environmental Policy Act (NEPA) process, environmental documents are
prepared that state:
- the purpose and need of a TxDOT transportation project,
- any
existing environmental and socioeconomic conditions,
- environmental consequences
of the project, and
- alternatives to the proposed alignment of the project.
The following GIS maps show environmental elements that are considered
in Texas highway construction projects.
The amount of data needed to make sound environmental decisions during the
NEPA process, like that contained in the GIS maps above, could cause an overload
of information. To assist in the NEPA process, Region 6 EPA developed an
assessment tool to systematically consider single and cumulative environmental
impacts. The
Region 6
EPA GIS Screening Tool (GISST) is designed to facilitate a better
understanding of environmental effects and allow the EPA to share technical and
regulatory data with industry, the public and other stakeholders.
This tool uses a mathematical formula to provide a weighted environmental
score to a GIS spatial grid indicating environmental concerns in a project area.
The 1K grid data can be symbolized on a map with a score of one (low impact) to
five (high impact) or Present/Not Present. The score is based on EPA-developed
criteria for census data, impaired streams, threatened and endangered species
data, flood data, national land cover data, aquifers, watersheds, roads, ozone
level, toxic release inventory data, soil data, hydrology units and
environmental facts.
Request GISST Data
As required by the Transportation Equity Act of 2001 (TEA-21), E.O. 13274,
and Section 6001 of SAFETEA related to linking planning and NEPA, TxDOT is using GISST as an environmental streamlining tool on transportation
projects. We will provide GISST data to other Texas government entities to
assist in NEPA processing time by identifying potential environmental areas of
concern.
|
