Index of Drinking Water Adequacy (IDWA): International and Intra-national Exploration

3. Global Situation on Drinking Water Adequacy

40 Index of Drinking Water Adequacy (IDWA) 40 Global Situation on Drinking Water Adequacy Ngo Quang Vinh This paper provides estimates of the Index of Drinking Water Adequacy (IDWA) for 144 countries for the most recent year for which component indicators are available. Inter-correlations between IDWA and selected human development and governance indicators are explored and implications noted. 1. Introduction The Asian Development Bank released the first ever Asian Water Development Outlook (AWDO)1 in late 2007. The report contained a composite index known as the Index of Drinking Water Adequacy (IDWA), based on an aggregation of five components (see Box 1) and computed for 23 Asian countries. The index was since fine-tuned, christened IDWA II, with the incorporation of water supply via house connections representing access instead of the general access 3 1 Asian Development Bank (2007). Global Situation on Drinking Water Adequacy 41 indicator (see Box 1).2 Further work on IDWA includes the one pertaining to IDWA for 15 Indian States.3 This paper extends IDWA to 144 countries of the world as against the coverage of 23 Asian economies in IDWA-I and IDWA-II. In view of the global coverage, the present variant of IDWA is labeled as IDWA-GLOBAL or IDWA-G for short. 2. Components of Index of Drinking Water Adequacy (IDWA-G) The 144 countries covered in IDWA-G encompass both industrialized and developing countries. The components of IDWA-G are explained below, for the sake of completeness and continuity though there is little difference between the components noted here and those in the earlier exercises (Box 1). Resources The index for this component is based on estimates of renewable internal fresh water resources per capita taken from the World Resources Institute (WRI) 2007 and the per capita figures are converted to a log scale. The index Rj for country j is calculated as follows: Resource Indicator for country j = (log log ) (log log ) min max min R R R R j − − ⎡ ⎣ ⎢ ⎢ ⎤ ⎦ ⎥ ⎥ × 100 where Rmin is the internal resource per capita of Egypt and Rmax is the internal resource per capita of Iceland. The raw data and the resource indicator for each country are in Annex 1.4 2 Seetharam, K.E. and Rao, B. (2010). See also paper 4 in this volume. 3 Seetharam, K.E. and Rao, B. (2009). 4 Due to the large size of the tables, we have opted to place them in the Annex. 42 Index of Drinking Water Adequacy (IDWA) Box 1 Components of IDWA-I and IDWA-II Resources: Estimates of renewable internal fresh water resources per capita are taken from the World Development Indicators (WDI) 2006, which refer to 2004. Access: The latest (2004) estimates of access are measured as percent of population with access to a sustainable ‘improved’ water source. [This access indicator was used in the original version of IDWA since known as IDWA-I, while IDWA-II uses house connections as the access parameter.] Capacity to Buy Water: Per capita GDP in PPP dollars is used as a measure of a nation’s capacity to produce/purchase and supply adequate amounts of drinking water. Use: This component calculates the per capita water consumption by the domestic sector, which is referred to as ‘drinking water’ in this paper. Quality: WHO data on diarrheal deaths per 100,000 people for the year 2000 are used as an indirect measure of drinking water quality. Access (House connection) In IDWA-II, urban house connections and rural house connections were calculated and used separately, which implies that each had an equal weight. The refinement in IDWA-G is to take a weighted average of the rural and urban access rates, the weights being the respective population proportions. As for data sources, the house connections rates by country are from the Water and Sanitation Information Website of the Joint Monitoring Program of the WHO and the UN Children’s Fund. Rural and urban population percentages are from the Population Reference Bureau website.5 5 See . Global Situation on Drinking Water Adequacy 43 House connection indicator for each country is available in Annex 2. Capacity Similar to IDWA-I and IDWA-II, per capita GDP in PPP US dollars is used as a measure of a nation’s capacity to produce/purchase adequate amount of drinking water. For minimum-maximum estimates from among the 144 countries, the respective figures are US$281...