Water poverty Analysis using Water Poverty Index (WPI) -A critical Review

Water as essential life giving compound, which is vital in keeping all the live alive life on the earth. In the recent decades, anthropogenic activities and many other reasons have created so much difficulties even in providing basic water supply for inhabitants from both surface and groundwater resources. This poverty for water or richness of water within the area, has to be calculated not only based on available water resources, but also by considering the factors such as accessibility, capacity, use and environmental factors Sullivan CA [1]. Water stress is an emerging issue in many of the developing countries since the rapid urbanization led to increase in population rate, economic growth which forced in increase in the solid waste generation and thereby decreasing the quality of water due to the pollution, deforestation and other anthropogenic activities and the water became inaccessible for human use. Water stress can effectively be evaluated using several methods among which Water Poverty Index (WPI) is the most widely used method. In this short review, we will be critically discussing about the same Sullivan CA [1].


Introduction
Water as essential life giving compound, which is vital in keeping all the live alive life on the earth. In the recent decades, anthropogenic activities and many other reasons have created so much difficulties even in providing basic water supply for inhabitants from both surface and groundwater resources. This poverty for water or richness of water within the area, has to be calculated not only based on available water resources, but also by considering the factors such as accessibility, capacity, use and environmental factors Sullivan CA [1]. Water stress is an emerging issue in many of the developing countries since the rapid urbanization led to increase in population rate, economic growth which forced in increase in the solid waste generation and thereby decreasing the quality of water due to the pollution, deforestation and other anthropogenic activities and the water became inaccessible for human use. Water stress can effectively be evaluated using several methods among which Water Poverty Index (WPI) is the most widely used method. In this short review, we will be critically discussing about the same Sullivan CA [1].

Water Poverty Index (WPI)
Water Poverty Index (WPI) is a simple, open and transparent tool, one that will appeal the politicians and decision makers, and at the same time empower poor people to better participate in water sector interventions and budgets development in general Sullivan CA [1]. The elementary advantage of the index is that it encapsulates more than one measure of influencing factors in a single number, and one line representation of the whole picture.
In its first iteration, Sullivan et al. [2] developed the WPI to consider all the aspects involved with water management. Consequently, the WPI explains water poverty according to five components -Resource(R), Access (A), Capacity(C), Use (U) and Environment (E). The calculation process for the WPI is simple, cost effective and easy to understand even though it requires large micro data sets. Today, the WPI method is extensively used to study water poverty. To calculate the values for the above-mentioned five components of WPI, Cook et al. [

WPI Structure
The five components explained above are combined to calculate the WPI. The final value of WPI for a particular location can be calculated as described by Sullivan et al. [1] is presented below.

R -Resource
A -Access U -Use C -Capacity

E -Environment
These weights (WI) are constrained to be non-negative and sum to unity. Each of the components is standardized so that the value of WPI falls between 0 and 100.The highest value 100 is taken to describe the best situation whilst the worst is 0.
The various sub components which help to calculate the five components of WPI are listed in below (Table 1). Percentage of area with natural vegetation.

Critical evaluation
If the In case WPI is updated at reasonable intervals, it can be used to monitor the progress. . Even though WPI had found a great relevance in the sustainable water management sector in policy making, there are few defects in the current index. In particular, two major weaknesses of WPI index have been identified by Gine Garriga [9]. Rather than using the available data for the calculation of WPI, the writer's developers of the index have used the data needed to construct WPI. Another major drawback of the current WPI is the equal weight age given to the components is not justifiable. Moreover, a single number alone cannot reveal anything about the complexity of water issues. So alternatives to tackle these issues are very important. Further studies have proved that multivariate techniques can be used to give the weight age. In this technique, weight age is given based on the variations in the original variables Gine Garriga [10,11]. Furthermore, detailed studies are required to criticize the existing WPI and to suggest a new improved WPI calculation method for the sustainable future.

Conclusion
This brief review tries to portray overall picture of water poverty index as a tool to evaluate water situation of the particular region, which helps policy planners to evaluate the threats and to take immediate action. Similarly, decision makers, after estimating all the five components, will be able to realize and identify the sectors which need significant attention in regards to the water needs. In a nutshell, the WPI makes us understand the difficulties of water issues by integrating the physical, social, economic and environmental aspects by linking water issues to poverty. Most importantly it is suggested to make further detailed research to overcome the critics to have a holistic tool which yields precise results. Use of multivariate techniques to the weight assessment is suggested to get better results.