GIS is a tool, just the same as a hammer. Without wanting to be rude, the question is like asking, what can you build with hammer and nails. Thus it would be good if you provided more details. As general response, GIS can and is usually used for environmental impact assesment, from flood areas of a reservoir, to shades and visibility of wind parks, to neighborhood analysis for waste sites,to whatever else you can imagine. But GIS will only provide you with needed information to carry out the assessment. For the assessment you need to use other tools and the most important one is a reference frame  (laws, standards, wishes) and your judgement.

Dear Rafael,

                     i know that different these can be measured from gis tools but I want to know about some models for environmental modeling, may be my asking language is not proper

Sorry for not being able to provide you with a straight forward answer again Partha. Environmental modelling is also very broad and in did, some type of environmetal modelling can be made using GIS. One example from hydrological modelling could be to assess the impact of some land use change. In this case you can use GIS as information source or if you add for example the extensions QSWAT to the GIS software QGIS, then you can carry out the assessment "within" GIS (this is just an example).

Depending on the GIS software you may be using, it may have more, or less environmental modelling capabilities, but these are usually restricted to spatial applications not including its temporal dynamics. Traditional environmental modelling, in which you analyze sources, fluxes and sinks in time, is still not that common within a GIS environment. The reason is very simple, the maths of a model describing an environmental system are already complex enought in one dimension (lumped) not to say in two or three dimensions.

Again, if you could be more specific I could maybe help some more.

In my researchgate 2013 is an EIS that used GIS in various ways.  I used it to compile erosion, sediment and estimated mean suspended sediment concentrations for various size hydrologic units with a variety of land uses.  For those hydrologic units where management intensity was high, we attempted to mitigate intensity first, and if that was unreasonable, we went out to check stream stability and channel function to make sure streams were stable.  I do agree that there is a tendency with GIS to pull together a lot of detail, but it may take professional recognition and interpretation relative to the data, and in some instances field checking.  Most GIS professionals are interested to pick up on specifics that various professionals point out, but are not necessarily a substitute for specialized experience and training on the various resource areas.  There are still some aspects of Geospatial technology that do not work well enough on their own and need some professional tweeking, whether that means a GIS and/or specialized professional to recognize something did not work right and how to correct it.  With the potential of GIS, it may be easy to snow the readers of an EIS of its competence at addressing resource impacts, but it is the resource specialists that need to put the data in perspective as to reliability, limits, assumptions, etc. so it is effectively applied, not overstated or understated.  GIS is a great tool, we can put out maps and products so professional looking that the reader can be fooled as to the detail and reliability of the content.  As professionals we must make sure we have done our due diligence in using the tool, but not replacing insitu observations, measurements and professional analysis and experience with the remote detail that is sometimes overwhelming.  As both GIS and resource professionals, we must take care in qualifying and interpreting the results.  I would probably put models in the same category, they are tools to consider that may develop detail that may overwhelm, but takes professionals to evaluate if model is appropriate and applicable to circumstance.  The tendency may be to take results of models, and not do much in qualifying them as indicators for comparison of alternatives in environmental analyses only, and their detail is not to be considered as highly correlated or factual data without more verification.  I must put in a plug for LiDAR technology.  It provides more spatial and resource detail than most professionals are able to pick up with brief reconnaissance, and can point professionals toward specific question areas.