Modifications
of BEES
As has already been pointed out BEES was developed for water resources
development projects of the United States Bureau Reclamation. Many attempts
have been made to modify BEES. Depending on the nature of the project and
the geographical and environmental setting modifications have been proposed
in the categorisation of environment into various components parameters. As
a logical consequence the parameter importance units have also been assigned
afresh. At some instances new value function curves also have been added.
In most of the cases, however, the overall scheme of the BEES has remained
more or less unchanged.
Lohani and Soo (1982) designed an environmental evaluation system for water
resources projects in Thailand. They reduced the number of parameters to 51.
According to the scheme the 51 parameters are organised into 3 categories
(ecological, physicochemical and human-interest) and 9 components. Modifications
and refinements have also been made in value function curves to suit local
conditions. One interesting feature is that the scheme increases the range
of environmental quality values to 0 to 10. Together with 51 parameters this
makes the total possible environmental score to be 10000! This high a resolution
is meaningless and confusing. From a case study published (Lohani and Halim
1983), it is apparent that the EES proposed by Lohani and Soo (1982) does
not require all the parameters to be considered. Thus the total environmental
score does not possess any qualitative significance. Furthermore this methodology
does not mention any criteria for assessment of major and minor red flags,
and data needs.
Kundu (1993) modified BEES with the objective of using it for mining projects
in India. Under the scheme of modification, environment has been sub-divided
into the following four categories:
1. Ecosystem
2. Physical Environment
3. Aesthetics
4. Socio-Economics
These categories are further subdivided into 8 components and then finally
into 39 parameters. Kundu's modification allows relatively fare representation
of land, air and water. However, too much weightage (36%) has been given to
aesthetics and socio-economics, while land, - the most significant from the
point of view of mining-, has been assigned only 9.6% weightage. One important
improvement that can be observed from Kundu (1993) is that double counting
of parameters has been carefully avoided. Moreover the same list of parameters
has been recommended for both underground and opencast mines. Certain phenomena,
e.g. 'land subsidence', have been erroneously included as parameter. Value
function curves have been developed for Indian conditions (Kundu and Banerjee
1994) so that its applicability can be increased.
NEERI (1994) proposed another modification of BEES to make it applicable to
industrial projects. Under the proposed scheme 'Environment' has been categorised
into Biological Environment, Environmental Pollution Aesthetics and Socio-Economics.
However, instead of accepting the pre-assigned set of parameter importance
units (PIU), NEERI (1994) proposed sensitivity analysis to be carried out
on the PIUs of all the four categories taken together. Pre assigned values
of PIUs were estimated by using paired comparison technique and were found
to be 400, 300, 100 and 200 respectively for the above mentioned categories.
From the sensitivity analysis carried on these values it has been found that
a 5% increase in the above value of PIU for the 'socio-economics" category
will make the project favourable under all conditions. The NEERI study further
revealed that if only bio-physical environment was considered (i.e. if the
categories of aesthetics and socio-economics are excluded) the project studied
would be acceptable when and only when more that 65% weight is assigned to
biological environment. That would mean assignment of only 35% or less weight
to the category, 'environmental pollution'.
Several other applications of BEES have been reported. BEES approach has been
successfully applied to a rapid transit system (Smith 1974) and to highway
projects, pipeline projects and wastewater treatment plants (Dee et al. 1973).
Optimum Pathway Matrix
Optimum pathway matrix analysis approach to environmental decision making
is a scaling weighting checklist developed by Odum (1971). This methodology
has many features similar to BEES. A checklist of 56 environmental parameters
is incorporated and for each of the parameters, measurable indicators are
specified. Developed specifically for highway projects this methodology groups
the environmental parameters into four classes of factors, namely,
* economic and highway engineering factors;
* environmental and land use considerations;
* recreation considerations; and,
*social and human considerations.
As may be seen factors not directly related to the biophysical environment
received greater attention.
Odum (1971) presented a test case for evaluation of eight highway alternatives.
They gathered necessary data from existing reports, documents and other secondary
sources. Impact on a parameter due to an alternative is represented by following
a scheme of unitisation. When there are 'n' parameters under consideration
for 'm' number of alternatives the unitisation factor for the ith parameter
is calculated by the following mathematical formation:
Where
Sij = unitization factor for ith parameter for the jth alternative.
Xij = estimated value for ith parameter for the jth alternative
i = 1,2,3,…....n
j = 1,2,3,……..m
The unitised value for ith parameter and jth alternative can now be calculated
by the following expression.
UVij= Sij . Xij
Where
UVij= Unitised value for ith parameter and jth alternative
Odum (1971) cited eight alternative highway routes for which the 'area to
be greatly affected by noise' (parameter number 23) for each alternative were
as follows.
A significant difference between BEES and Optimum Pathway Matrix is that the
later does not assign parameter importance index beforehand. Relative importance
weights of the parameters are determined separately for long-term and initial
effects. Relative importance weights of the parameters are assigned through
subjective assessment by an interdisciplinary team. Odum et al. (1971) suggested
a range of value between -20 to +50.