2.1 ENVIRONMENTAL IMPACT ASSESSMENT
Environmental Impact Assessment (EIA) is a procedure which provides an opportunity to identify the potential environmental and social consequences of the proposed developmental activity and also able to suggest strategies for mitigating those identified adverse effects right at the planning stage. This way the major contribution of EIA in environmental management may well be in reducing adverse impacts and making necessary alterations in the developmental proposals. The overall methodology used in the present study has been described in the following sequential sections.

2.2 CONSULTATION OF BACKGROUND INFORMATION
As a foremost requirement of the present study, detailed relevant Feasibility Reports prepared by M/s IOCL, Refineries & Pipelines Division, New Delhi were obtained and consulted. These reports were used throughout the field studies as a major reference material. Maps depicting routes of existing and proposed pipelines with various allied facilities en route provided by the IOCL were referred intensively during the field reconnaissance and intensive studies. These maps were of great help in locating sample points.

In addition to the background information and maps provided by the IOCL relevant toposheets of Survey of India in the scale of 1:50,000 were also used during the field studies. Information on Protected Areas (PAs), important wildlife habitats, floral and faunal diversity for all concerned areas were collected from the WII's National Wildlife Database. Simultaneously bibliographic search for published information was undertaken by consulting individuals/libraries of concerned organisations viz. State Forest Department of Haryana and a number of other institutions.

2.3 MACRO LEVEL ASSESSMENT
The second step in the present study was the macro level assessment which involved the identification of protected areas (National Parks, Wildlife Sanctuaries) and ecologically sensitive ecosystems/wildlife habitats en route the proposed pipelines. It was considered that the disturbances associated with the construction activities would be uniform all along the pipeline route, the impacts on ecologically sensitive areas en route would be more significant and therefore, need to be evaluated more carefully.

2.4 RAPID FIELD ASSESSMENT
The field studies were conducted during May, 1994. The reconnaissance along the pipeline route included an assessment of overall land use pattern and the extent of ecologically sensitive areas. Surveyed sample points were largely randomly located. At each sample point, data on the pipeline reference number, land use pattern and wildlife values (existing and potential) were recorded. The crucial wildlife habitats thus identified during the reconnaissance were revisited for intensive studies. Impact assessment methodologies used for the intensive studies were specific for each wildlife habitat category.

2.5 EVALUATION AND ASSESSMENT CRITERIA FOR CONSERVATION SIGNIFICANCE
The assessment of how and why a species, a population, a community, a habitat and an ecosystem as a whole are threatened is crucial to rational decision making before the implementation of a major developmental project. Spellerberg (1992) has provided a set of ecological guidelines for determining priorities for nature conservation. Taking a clue from these guidelines a set of evaluation criteria for the assessment of conservation significance of various wildlife habitats/ecosystems en route the proposed pipeline project has been evolved and described here.

(i) Legal status of wildlife habitats :
Under the Forest Conservation Act, 1980 and the Wildlife (Protection) Act, 1972, forest and wildlife areas have been provided varying level of protection, legal status and also provisions of different levels of uses. Accordingly five categories viz. National Park (NP), Wildlife Sanctuary (WLS), Reserved Forests (RF), Protected Forests (PF) and privately owned areas were recognised and conservation significance rating viz. 5,4,3,2, and 1, respectively to these have been assigned. It is obvious in this case that a National Park has the highest conservation importance.

(ii) Extent of wildlife areas:
Size or actual extent of a wildlife area is critical because the capacity to support the range of diverse flora and fauna of an ecosystem would depend on the total area included for or available to conservation such values. Following evaluation criteria have been evolved with regard to the size of a grassland, a forest and an open scrub. Categories of coastal and marine ecosystem and wetlands (rivers, lakes and village ponds) have been excluded from this particular evaluation criteria on account that only one major coastal and marine ecosystem i.e Gulf of Kutch MNP and WLS lies in the route of proposed pipeline. Since MNP has a National Park status and has been well recognised as a megacentre of coastal and marine biodiversity, the importance of Gulf of Kutch or MNP as a whole has to be considered as an extremely important ecologically sensitive entity.

Similarly for various categories of wetland a separate criteria on the basis of their seasonality has been evolved. These criteria classes are: (a) Wetland having water only during the monsoon season of 3-4 months, (b) Wetland having water during the greater part of the year except the dry summer season, and (c) Wetlands which are perennial. These wetlands have been assigned ranking values 1,2, and 3, respectively. These values are in an increasing order of conservation significance.

(iii) Status of wildlife habitat ecosystem - Species diversity, biological productivity and present level of threat:
In view of a very large extent of proposed pipeline, and adoption of rapid assessment methods, it was not possible and desirable to present detailed inventories of flora and fauna for each area, assessment of overall species diversity, and estimation of primary and secondary productivity. However, based on actual field observations, secondary data collection and professional judgement status value to each wildlife habitat was assigned as explained below:
 

In summary, a wildlife habitat/an ecosystem can achieve the maximum score of 11 and a minimum of 3 by taking into account assigned values as per the above items (i), (ii), and (iii).  Thus, a wildlife habitat/ecosystem securing higher score by above criteria signifies a greater importance with respect to conservation.  The explanation for the final evaluation criteria is presented in the following tabular statement.
 

After describing the baseline status of each wildlife habitat/ ecosystem located in the pipeline route, the probable impacts during the construction, operational and maintenance phase have been visualised. These impacts have been visualised on the basis of available scientific reports on ecological changes and professional judgement. At the end, mitigatory measures for such impacts have been recommended.