SPECIAL REPORT: No rains, but the Central Plains still flooded

Several communities downstream of the Chao Phraya River have been living in pain as their houses and properties have been flooded for weeks despite no more rains present in the area. The changing climate, the limited flood management facilities, and the change of landscapes are all said to be critical factors contributing to the disaster

Grandma Jerm in her 80s climbs out of a window on the second floor of her house, gets into a boat, and paddles towards a drier land by the roadside around a kilometre away in the hope to get food donations. It has been more than two weeks since she had to paddle in and out of her house like this as her daughter and nephew are not good at paddling like the old generation and are too scared of the floodwater, which is now a few meters deep already.

“It’s become harder and harder living in the floodwater like this, but we have no choice,” said Grandma Jerm, while taking some rest at a newly set up bamboo-based makeshift wayside shelter of her neighbour on the roadside. It has become their so-called new home as they tease themselves while waiting for food and drinking water.

Grandma Jerm is among hundreds of families in age-old riverrine communities in Tambon She Nam Rai in Inthaburi district of Sing Buri province that are located outside a dyke, therefore was flooded after the Chao Phraya dam upstream in Chai Nat province could no longer hold excess water following the influence of Super Typhoon Noru in late September and needed to discharge it downstream.

Her home area, the Chao Phraya basin, is among the areas badly hit by the storm this year and is now demonstrating how the situation can turn from bad to worse by the water management afterwards.

The Chao Phraya basin is dubbed as one of the country’s best irrigation areas as the governments have invested extensively in irrigation development for decades. Besides the prime water regulator on the Chao Phraya River in Chai Nat province, the Chao Phraya dam, the area is covered extensively by a vast network of irrigation facilities including irrigation canals and sluicegates. But all are principally for irrigation purposes. As the basin is critically challenged by unusual rainfall and flooding this year, it’s proved once again the extent to which the old water management and facilities can cope.

Clockwise: The Chao Phraya dam rushes to discharge excess water from upstream; As of Oct 17, the dam lowers the discharge volume, but it’s still beyond its discharge capacity at 2,850 m³/s; Mr Chawalit leads a team to analyse the situation at the war room at the dam site; Bang Chom Sri sluicegate, which broke in 2011 and sent a large volume of floodwater downstream, becomes a monument today as a new sluicegate is built to fix the flaw. But it’s said to reverse the flows, discharging the floodwater from some fields nearby to the mainstream river instead, further complicating the situation; The RID erects a sign to warn passers-by about the floods on their way; The RID attempts to divert excess water to a drier land on the other side of the road-based dyke; Dykes in several locations are broken due to the increasing water pressure following the increasing discharge; Gabions are placed here and there to fix the holes caused by the collapse of dykes or barriers; Seen in the last photo is the broken road section connecting Phak Hai-Chao Jed sluicegate in Ayutthaya, prompting the floodwater to surge downstream. Photos: Sayan Chuenudomsavad

The downpour

According to the Royal Irrigation Department, before Super Typhoon Noru made landfall in Vietnam on September 28 and downsized into a tropical depression when entering Thailand, the country had already experienced heavy rainfall brought by seasonal monsoon troughs and low pressure, prompting rains to fall over a wide range of areas, from the upper North over major dams down to the Central Plains.

As recorded by the department, the Chao Phraya dam already discharged water on the day the storm hit the country at 2,300 cubic metres per second (m³/s). The maximum water discharge capacity of the dam stands at 2,850 m³/s, being equivalent to around 246 million cubic metres (m³) a day.

As the storm passed the country, water management authorities estimated that at least 11,500 m³ of water would be flowing into major dams, exacerbating the situation as some of them would be overfull and need immediate water discharge. Among those are two prime dams of the Chao Phraya basin, the 939-million-m³ Khwae Noi Bamrung Daen dam in Phitsanulok province and the 960-million-m3 Pasak Jolasid dam in Lopburi and Saraburi provinces.

By October 3, the department had reported to the National Water Command Center, chaired by Deputy PM Gen Prawit Wongsuwan, who travelled to the area to inspect the situation, that it would start to divert water into the target vast fields to help retain the excess water so that the Chao Phraya dam’s discharge could still be kept below its maximum capacity, around 2,700 m³/s. What is feared the most is if it discharges water beyond its maximum capacity, communities downstream will be flooded as a result.

A few days later, the department needed to discharge the water at the dam beyond its maximum capacity (2,900-3,000 m³/s) as the water approached its peak (recorded at around 3,100 m³/s at the C2 station in Nakhon Sawan province on October 9), and kept flowing downstream, prompting the excess water to flood communities and burst the dykes in several locations along the river.

It took the department almost two weeks to keep the water discharge at the Chao Phraya dam under 3,000 m³/s (2,947 m³/s on October 19), and the department projected that the water discharge at the dam could be below 2,700 m³/s at the end of this month.

That also means up to 500 m³/s or around 43 million m³ of water a day discharged into the 10  target vast fields. On October 6, the department reported that around 60% of their combined storage capacity, or over 760 out of 1,300 million m³, was filled in already. During that period, the dyke bursting, severe flooding and fighting between upstream and downstream communities as well as those living outside the dyke and in the vast fields were reported along the Chao Phraya River.

I Photos: Sayan Chuenudomsavad

The truth behind tears

Further downstream in Bang Ban, Sena, and Phak Hai districts in Ayutthaya province, 64-year-old Sakorn Attharos has been living in the flooding even before the arrival of Super Typhoon Noru.

Living by the narrow section of the river, her community in Tambon Wat Yom in Bang Ban district is among the first communities that will be flooded if the Chao Phraya dam discharges water beyond 700 m³/s. And this year, she faced it right after early September.

“It’s become part of our lives that we have to accept, but this year is torturing as the water rose too early. And it would last longer in our community,” said Aunty Sakorn, whose house has been flooded up to the second floor, leaving a narrow gap of around one foot between her bed and the floodwater. 

For those who are not fortunate like Aunty Sakorn, they may leave their flooded houses which are completely submerged under the floodwater and sleep in makeshift tents by the roadside or in temples. Wanna Khemnak’s family, like several others in the same Tambon, have been living in a makeshift tent for nearly two months now. Her family set it up in Wat Thammajak Temple’s compound without knowing whether she can go back to her house and live there again as it could by now be damaged beyond repair.

“For those making a living day in and day out like me, our houses are most important, but how could they stand the flood like this?,” asked the 50-year-old housekeeper, noting uncertainty over further assistance.

As explained by Chawalit Chalom, the director of the Bureau of Water Management and Operation and Maintenance at the RID’s Regional Irrigation Office 12, in charge of the lower Chao Phraya basin, flood management in the lower basin has many challenges following the change of the climate as well as the topography of the area itself.

According to Mr. Chawalit, the Chao Phraya River has different widths at different sections, prompting the communities by the river prone to flooding at different degrees. The department has set the lowest level of flood risk at around 700-2,000 m³/s, and the communities outside the dyke in Sena, Phak Hai, and Bang Ban in Ayutthaya and Phong Pheng nearby in Ang Thong province will be among the first prone to flooding as a result. The next level of flood risk is set at 2,000-2,200 m³/s and the communities further upstream in Wat Chaiyo communities and around in Chaiyo district in Ang Thong up to Wat Singh community and around in Inthaburi district in Sing Buri province would be prone to flooding at this level. 

After 2,200 m³/s, the next risk is set at 2,200-2,400 m³/s and the communities in Pamok district in Ang Thong up to Sappaya district in Chai Nat province would be prone to flooding at this level. And the last level of flood risk is set at over 2,400 m³/s and communities closet to the dam in Sappaya and further away from the riverbank in Inthaburi in Sing Buri and Chaiyo in Ang Thong would be prone to flooding as a result.

Realising the situation, the department tried at best to manage the floodwater, Mr. Chawalit said. One of the approaches is using the vast fields to help take excess water out of the system. Mr. Chawalit said the vast fields have become one of the critical tools to help in flood management for the Central Plains in recent years. The idea was first developed after the major flooding in 2011 and so far the department managed to find up to 10 vast fields along the lower Chao Phraya plus the Bang Rakum field in Phitsanulok province. Altogether, they are 1.5 million rai and have the capacity to retain up to 1,300 to 1,700 million m³ of water.

But as the water is excessive this year, almost all the fields are overfull, and this is an emerging issue as it could raise conflict between the state and residents in the fields. The critical challenge, Mr. Chawalit said, is the fact that the state has not yet put in place soft measures to help facilitate the use of the vast fields for flood management. These include clear compensation, he said.

So far, concerned authorities have to negotiate with the residents in order for them to use the vast fields, which are their rice fields, and promise they will get water for the next growing seasons in return. They would then come to an agreed term of the flood depths, but this year, as recorded on October 17, 10 lower Chao Phraya fields took around 1, 835 million m³ of water already, or exceeding its capacity of 1,300 m³ by 40%. For instance, the largest field of Thung Chao Jed in Ayutthaya, which is around 320,000 rai and has 350 million m³ storage capacity, saw the retained water over its maximum by 26% or 92 million m³.

“Amidst the change of the climate, our landscapes have changed and our communities have expanded whereas our facilities are limited. Water needs to flow down and it tends to seek its way to go, but it’s being blocked and has nowhere to go now. That’s why it’s become a critical problem for us at present,” said Mr. Chawalit.

Clockwise: Wat Khun Inthapramun community and nearby areas in Ang Thong are flooded as a reinforced dyke by the Chao Phraya broke, sending a surge of floodwater into the Noi River that then floods them; A TAO officer drives a boat through floodwater in Thewarat community near the temple to mark the flood levels for the residents who need to get back to their flooded properties; An iconic sleeping Buddha sculpture in Wat Khun In narrowly survives the flooding; Sing Buri’s downtown reinforces a dyke to prevent itself from flooding; it’s flooded eventually as the water finds its way through holes and flushing tunnels; A spirit house has not survived the flooding; So is the RID’s sluice gate in Tha Din Daeng in Ang Thong, where the whole community is flooded; The residents in Chaiyo district try to fight with the floodwater coming down from a broken dyke upstream; Officials try to protect historical sites in Ayutthaya from the flooding this year. Several have not survived, however; Some temples are flooded, but residents try to protect the properties as best they can. Seen in the photo is a principal Buddha image, Luang Por Dam of Wat Thammajak Temple in Bang Ban. Photos: Sayan Chuenudomsavad

The challenges

As examined by the Office of National Water Resources (ONWR), the average rainfall this year (January 1 to October 22) is 1,775 millimetres (mm) or around 21% above the 30-year average and only 0.2% or 3 mm below that of the major flooding year of 2011 (1,778 mm). In the Central Plains, it’s 5% above the 2011 level.

The peak of the water in the Chao Phraya River was 3,105 m³/s, measured at the C2 station in Nakhon Sawan province, but there was also water from the Sakae Krang River in the West, measured up to over 650 m³/s in some days, flowing into the Chao Phraya before the Chao Phaya dam, prompting the water flowing towards the dam at the rate of 3,707 m³/s, close to the 2011 peak at 3,800 m³/s.

To try to keep the water discharge at the Chao Phraya dam as low as possible, concerned authorities, therefore, discharged the excess water of around 540 m³/s into the vast fields. The peak allowed at the dam was at 3,180 m³/s, according to Dr. Surasee Kittimonton, Secretary-General of the Office of National Water Resources (ONWR).

However, the embankment of the Chao Phraya generally stands against the water discharge at around 2,500 m³/s or it would start to burst, otherwise. That’s the reason why several sections of the river burst as evidently recorded when the water flew through the dam beyond this level. In addition, if the dam discharges water beyond 1,500 m³/s, it could complicate flows in the Noi River in its West and cause more severe flooding to communities downstream. 

The office has projected that the Chao Phraya dam would discharge water below 700 m³/s around the end of November.

PM Gen Prayut Chan-o-cha, meanwhile, made a visit to inspect some fresh incidents in Sing Buri province today, where reinforced dykes burst in several locations. He instructed concerned authorities to provide assistance to the residents and address their damages and compensation. He also instructed them to equip themselves better to deal with the changing climate. No details are elaborated.

“Nobody told us clearly how the water would rise and until when it would last. No one has come to tell us up until now,” said Ms. Wanna, echoing Aunty Sakorn and Granma Jerm, who all said the flooding season has extensively changed and become unpredictable, unlike what they were used to; “It comes and then it goes.”.

As of October 22, 71 districts in 11 provinces in the Central Plains have been flooded, according to the ONWR.

This special report is part of the Environmental Challenges in Recent Times series.