Damages
The water and sanitation sector is estimated to have incurred damage of approximately 3.5 billion Baht, which are almost equally divided between the water supply and sanitation sub-sectors. In the water supply sub-sector, the biggest share of damage occurred to water surface systems or groundwater wells in rural areas (1.8 billion Baht), as well as to water intake structures (28 million Baht) and water treatment plants (31 million Baht) in urban areas. Almost all damage in the sanitation sub-sector occurred in connection with urban wastewater treatment plants (1.6 billion Baht). For the purpose of this analysis, individual household septic tanks and related damage and losses are included in the Housing Sector, impacts of water quality on public health such as increased prevalence of water-borne diseases are calculated under the Health Sector, and impacts on environmental pollution through wastewater is included in the Environment Sector.
In the rural water supply sector, damage is estimated at approximately THB 1.8 billion. The reason for this relatively high value of damage compared to urban water supply is the almost exclusive reliance on wells or small-scale surface water supply systems (65 percent of which are groundwater wells and 35 percent surface water sources). Whereas some of this damage refers to damaged pumps or other control panels, some wells were damaged to such an extent that they needed to be shut down and replaced with new wells84. An example of types of damage is given in Table 26. Due to a lack of further data, estimations from damage and losses in two provinces (Nakorn Sawan and Chainat) were extrapolated to other provinces that were affected by floods.
For urban water supply damage is estimated at 70 million Baht. This assessment is based on information received by the Provincial Waterworks Authority at central level, the Metropolitan Waterworks Authority for Bangkok metropolitan area and observations made during field visits to Nakorn Sawan province as well as the largest MWA facility in Lak Si. For public or private municipality-run water supply systems, no actual information on damage or losses was available at the time of the assessment at a central authority85. In order to include an estimation of the damage and losses incurred, the following estimate served as basis: 75 percent of urban water schemes outside Bangkok metropolitan area are managed by the PWA, whereas 25 percent are managed by the municipalities (or respective private operators). The amount of damage and losses incurred per province was then calculated as an additional 33 percent of those estimated for PWA-run systems.
Due to sufficient prior warning and preparation time, MWA managed to protect all four Bangkok-based water treatment facilities86 from major flood impacts. The October-November 2011 floods in Thailand reached the largest of the four facilities in Bangkok in mid-October. The last time the MWA had to prepare for a serious flood was in 1995, the 2011 floods are assessed as much more extensive.