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Application of Geographic
Information
System (GIS) in Spatial Environmental Planning
S patial
Environmental Planning is a proven tool for protection of environment
and related resources. The environmentally relevant land uses such as
industry and trade, mining/quarrying, housing, roads, etc., that can
pose impacts/risks on the environment, should to be properly planned.
For proper and systematic planning, accurate and rapid analysis of
various thematic information is required, wherein GIS (Geographic
Information System) plays an important role. Environmental Planning
involves a large amount of data/information to be compiled
systematically and analysed spatially so as to arrive at environmentally
feasible land uses. GIS is a tool that can handle such complex problems
involving multiple databases and spatial analyses and create new
knowledge for development.
Geographic Information Systems
have become an important decision-making tool for public policy-making,
particularly in environmental planning and management. GIS has an
important role in environmental planning and management because of its
ability to link information with location. Through GIS, thematic spatial
information can be analysed quickly. The various processes of
environmental planning, such as overlaying of thematic information,
buffering of sensitive areas, extraction of one theme from multiple
themes, proximity of one feature with other relevant features can be
very rapidly and accurately done with the help of GIS. Forecasting of
future environmental scenario - one of the main pillars of environmental
planning - can be easily carried out with the help of GIS. All the
environmentally related thematic information is stored digitally in the
GIS and can be easily retrieved, updated, modified, analysed and
presented.
SEA, DEA and ZASI
The State Environmental Atlas
(SEA), District Environmental Atlas (DEA) and Zoning Atlas for Siting of
Industries (ZASI) involve spatial analysis of the various environmental
themes, subject to particular logical criteria developed so as to
achieve the objective of sustainable development. The main components of
the spatial environment - land, air and water - have each to be
individually analysed, after which the combined affect on them due to
location of industries has to be studied. The complexity deepens due to
the huge amount of data to be handled and also due to the quality of
data. The methodology, for preparation of SEA, DEA and ZASI assesses the
environment for different category of proposed land uses in 1:10,00,000,
1:500,000 and 1:250,000 scale. In this approach, the present
environmental status of the districts and states is presented spatially
through various thematic maps followed by detailed analysis in the
Zoning Atlas study to find suitable sites for locating any industry.
Approach to ZASI
The Geographical Information
System has been extensively used to achieve the desired objective. GIS
addresses the following aspects of the SEA, DEA and Zoning Atlas.
•
Preparation of about
30 to 35 maps for DEA and SEA that include thematic maps and about 12
resultant maps derived from two or more criteria or maps for the Zoning
Atlas
•
Updating of thematic
maps as some features on which the maps are based are likely to change
in the future (e.g., Land use map - conversion of agricultural lands /
wastelands) into other uses
•
Zoning Atlas other
than showing suitable sites for industries also identifies the sensitive
zones where no industry can be located due to social, legal and physical
constraints, the air quality in the area, etc.
The preparation of SEA, DEA and
ZASI involves collection, compilation and manipulation of the desired
raw data available in whatever form for producing the manual maps using
conventional cartography. This prevents the usual delay while using GIS
with maps on different bases and on different scales. The manual maps
are then digitised and rechecked against the originals.
The handling of such a vast
amount of data even after using GIS is a task by itself. The following
were done for the preparation of SEA, DEA and Zoning Atlas with the help
of GIS:
•
The polygon, line and point features were stored as separate covers
•
Attribute data was assigned wherever necessary
•
A Master Base Map was developed and all the theme maps were prepared on
these Base Maps
•
Care was taken to see that there was no re-digitisation of the same
feature, i.e., the features remained consistent in all the maps
Zoning Atlas for Siting of Industries (ZASI)
for Alwar District - A Case Study
Development Alternatives (DA)
was awarded the work for preparation of DEA and ZASI by the Rajasthan
Pollution Control Board for Alwar, Kota, Baran, Udaipur, Rajsamand,
Sirohi, Bhilwara, Jaipur and Dausa districts. GIS has been extensively
used for analysis of thematic maps using overlay, buffering and
extraction tools. With the help of GIS, a base map was prepared
combining the information from SoI toposheet, Landuse - Landcover map of
NRSA. This base map has been used for all the subsequent thematic maps.
Zoning Atlas of Alwar district
has four parts. The first part contains Environmentally Sensitive
Zones/Areas to be avoided. This information is presented in terms of
biological diversity of an area and sensitive/incompatible land uses.
Part two presents information
on the category of air polluting industries and site suitability for air
polluting industries. The Landuse Sensitivity Map has been prepared by
providing buffers of 2, 3 and 5 km to the different features extracted
from the biological diversity map and Incompatible Land Use map.
Part three presents information
on the category of water-polluting industries and site suitability. The
water-polluting industries have been categorised with respect to types
of effluent, biodegradability, toxicity, discharge mode, load of
discharged effluent, etc.
Part four present zones/areas
for siting air and water polluting industries. These zones/areas have
been arrived by overlaying Landuse Sensitivity Map, Water Pollution
Sensitivity Zone Map and Biological Diversity Map and the Incompatible
Land Use Map. The final suitability map has twelve combinations of
sites/zones.
Mapping is the most important
ingredient in Spatial Environmental Planning technique. To evaluate the
impacts of the proposed developmental projects upon the surroundings in
which they are set, it is necessary to understand the environmental
characteristics and environmental quality of the surrounding area. These
characteristics can be depicted by these sets of maps, which provide
detailed information regarding the land use, type of settlements,
drainage and irrigation, hydro geomorphic features etc. These thematic
maps enable us to take various developmental policy decisions like
formulation of industrialisation strategies, decide the direction of
future urban growth, etc. q
Avanindra Kumar
akumar4@devalt.org
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