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Historical records of floods in Chiang Mai
(for other information about waterways and management, click here)
Rivers occupy a special place in the traditional and spiritual (animist & theravada buddhism) context of the early Mon and Thai kingdoms and is still visible today through major religious celebrations such as Loy Kratong and Songkran, in which water plays a central role and the traditional belief towards Phra Mae KhongKha (mother river).
In the early Lanna kingdoms (13th-14th century), capitals (Chiang Mai, Chiang Rai, Chiang Saen) were founded along main rivers to exploit water and use it for efficient transportation and as such, the Ping river was a key channel of communication towards southern cities such as Haripunchai and Sukhothai and later on, Ayutthaya and Bangkok. Rivers were progressively tamed and disciplined for survival (cultivation, irrigation, transport, trade) and strategic (defense, communication) concerns. As towns were established in the direct proximity of rivers, it created large wet-rice cultivating states resting on a vast irrigation network. In the 13th century, the Lanna kingdom developed a series of laws, regulations and cooperation system between villages to manage the เหมือง-ฝาย (‘muang-fai’, tr. Canal-weir), the traditional irrigation system with a community-based infrastructure that can be traced back to the Mon kingdom of Haripunchai survived until the second half of the 20th century. The muang-fai system consists of weirs and channel diversions in a river, made of bamboo stakes, logs, leaves and stones to bring water in a subordinate canal where irrigation water can be brought to rice paddies through a system of sluice gates and dikes. Between the 1960 and 1990, most of this low-scale local infrastructure was replaced by concrete dams and larger canals run by the state through the Royal Irrigation Department.
In the Chiang Mai basin, the traditional muang-fai presents itself as meandering arms using paleochannels while artificially constructed irrigation canals are more straight and angular. Some of these structures are still present in the city, visible as winding secondary roads and some old weirs falling apart in secondary canals. Around major medieval urban centers, meandering loops were additionally used as defense or moats were dug and connected to the network of canals and rivers.
With such constraints, most major cities in rice-growing civilizations in the flood plains of Thailand have used monsoonal floods and river system to their advantage as seen in Chiang Mai and Lamphun (Ping), Lampang (Wag), Ayutthaya, Bangkok (Chao Phraya), Sukhothai (Yom), Uttaradit, Nan (Nan), Chiang Rai and Chiang Saen (Kok & Mekong). However, the advantage of seasonal flooding can also lead to abandonment of cities (Wiang Kum Kam), collapse of civilization (Angkor) or significant damage to ruins (Bagan) when the vulnerability of a river-based civilization cannot be or is not longer compensated by water management.
As minor flooding is an integral part of these cultures, Lanna architecture has traditionally a single story house on stilts, higher than the mean annual flood level, or floating houses attached permanently on a river or a canal. More permanent infrastructure of villages are build on natural levees where the higher ground protect from most flooding events. The settlement of the early Lanna kindgom around Chiang Mai show that these villages grew as meandering strands and clusters following various water channels and levees now concealed in the urbanization of Chiang Mai. One remaining indicator can be found in the toponomy of suburbs and villages starting with the prefix สัน (‘san’) (i.e. San PaTong, San Phisuea, San Phakwan, San Kamphaeng, San Sai, etc.) which means ridge or levee in the context of a floodplain, while past Ping and irrigation channels are also kept in the naming of suburbs with the term เหมือง (‘muang’) (i.e. Muang Mae Ping Noi, Muang Mae Ping Kao, Mae Ping Hang, Muang Buak Khok, Muang Saen Yot,…) which stands for canal; not to be confused with เมือง (as in Muang Chiang Mai), which stands historically for a town with defensive walls and moats.
Figure 1. Simplified map of Chiang Mai (1888-1902) with the Ping river, moats, Mae Kha and smaller canals and swamps are displayed (McCarthy, 1888)
Timeline of water-related historical events in the Chiang Mai area
Thai historiography has a strong tendency until the 1980s to neglect the description of floods and drought, especially in Lanna, to legitimize the modern Thai state. Most of the timeline is therefore a reinterpretation of old texts, description in chronicles of Lanna cities ignored by Siamese historiography and sometimes supported by recent archaeological, hydrological and sedimentological data.
768: Haripunchai is founded on the banks of the Ping river
1277-1280: Ai Fa canal, a 36 km long irrigation project, is excavated under king Phraya Yi Ba, the last ruler of Harinpunchai. This project evolved, 700 years later, into the Mae Faek irrigation project.
1283-1284: Flooding in Chiang Rua
1286-1287: Wiang Kum Kam is founded on the western side of the Ping river, with a 4-side moat connected to the nearby river and an extra levee along the Ping river.
1288: Wiang Kum Kam is the capital of Lanna
1288-1296: Wiang Kum Kam is flooded every year – ponded water and sediment deposition is too difficult to manage.
1293: Building of the reclining Buddha in the Haripunchai-built Wat Phra Non Nong Phueng temple in Wiang Kum Kam. The reclining Buddha is build to have spiritual control of the water of the adjacent Ping river.
1296: Lanna capital is moved to Wiang Nopburi and renamed Chiang Mai. Wiang Kum Kam remains a satellite village used for commerce, religion and defense outpost.
1336-1355: Wat Pan Sao, nowadays ruins in a more modern temple between Suan Dok and Ram Hospital was destroyed by a flood covering the area with 0.5 to 1.5m of sediments and debris
1300-1400: Excavation work is done for a canal on the South West of the Ping Hang, the old Ping riverbed, possibly done to reduce the flooding in Wiang Kum Kam.
1411±12: Last carbon-14 date obtained from the levee protecting Wiang Kum Kam.
1412-1552: Range of years when the Ping avulsion could have occurred.
1483±70 and 1477-1512 are the respective OSL and carbon-14 of the coarse sandy layer in the paleochannel next to Wiang Kum Kam.
1524-1525: Historical record of a catastrophic flood in Chiang Mai with many death reported at Siphum market (NE moat corner).
1545: Intense earthquake causing damage to Maha Chedi Luang & Wat Phra Sing in Chiang Mai on the 28th of July. Unlikely here, but some avulsions were caused by seismic shifts and 1545 had significant rainfall.
1558: Between 1500 and 1558, Wiang Kum Kam was abandoned based on archeological and architectural evidences.
1527: from that date, Wat E-Kang in Wiang Kum Kam is covered under 1.5 to 1.8 meters of sediments coming from the N or NW.
1774: from that date, Wiang Kum Kam is resettled after the successful Thonburi invasion campaign with no visible traces mentioned of the old capital.
1831: Catastrophic floods with more than 2 meters of water in the floodplain as well as possible further avulsions of the Ping river.
Figure 2. Distribution of large cities (>700000 inhabitants) with available AQI data and their peak monthly AQI average value for 2023. Cities from the IQAir list are in red while the cities ignored are in blue. Chiang Mai is circled in green and in among the highly polluted but by far not the highest. Bangkok is circled in orange.
Specific historical cases
Lamphun
Haripunjaya was founded in 768 on the western bank of the river Ping to have direct access to other Mon state of the Dvaravati conglomerate. It clearly contrasts with the current situation where the Ping river is 5 kilometers away from Lamphun historical centre, while an artificially dug Kuang river channel is passing on the eastern side of the old city.
Wiang Kum Kam
Wiang Kum Kam is described as founded in 1286-1287 on the western bank of the Ping river, a suitable place for settlement, surrounded by rice-bearing floodplains and easy access to the nearby Ping for trade and travel to Haripunchai and further downstream. The ancient capital is described in the annals of the Lanna kingdom has being flooded repeatdly, leading to the founding of Chiang Mai in a less flood-prone area. Wiang Kum Kam progressively disappeared from history into the legendary capital founded on the west side of the Ping. It wasn’t until 1984 that tablets were discovered buried in Wat Chang Kam on the eastern side of the Ping, revealing that Wiang Kum Kam, the lost city has switch to the other side of the Ping.
Eventually, detailed studies of the archeological sites revealed a paleo-channel passing just north of Wiang Kum Kam, now called Ping Hang. The Ping Hang was the main river connecting Wiang Kum Kam (and Chiang Mai) to Lamphun 23 kilometers away. It is now mostly dried up and filled or built but some present urban structures are still associated with its path such as highway [106] the old Chiang Mai – Lamphun Road which is a mildly meandering road sided by large Yang Na trees built on the 5 meters alluvial ridge that follow the current irrigation canal (Khlong Mae Ping Hang) in its southern part. Closer to Wiang Kum Kam, the original reclining Buddha statue built in 1293 at Wat Phra Non Nong Phueng to protect from Ping river floods is now 3 kilometers from the Ping, but only 150 meters from the dried bed of the Ping Hang. The auspicious statue is still seen as a protection from floods in recent times. The major flood of 1952, when floodwaters actively used the Ping Hang riverbed, spared the temple nearby.
The date of the final flooding of Wiang Kum Kam is unknown but is thought to coincide with the avulsion of the Ping into its current bed. It is possible that excavation work done in the 14th century for a canal have helped the Ping to take its current path but evidence from the amount and coarseness of sediments that covered the city indicate that the final flood that led to the abandonment of the city would have more destructive than the equivalent 2005, 2011 or 2024 floods. A possible date for such event could be the 1524-1525 floods that are among the few natural disasters mentioned in archives and chronicles.
Figure 3. Palaeochannel of the Ping Hang and ruins of Wiang Kum Kam between the current Ping river and roads [3029] and [106] (Teo, 2018).
Past river channels
A series of paleochannels named Muang Buak Khok, Muang Mae Ping Boi, Muang Saen Yot and Muang Lamphun are also the result of avulsions that have occurred in the past 500 years after the destruction of Wiang Kum Kam. Since these would have occurred in farmland, there is no mention in the litterature.
The Khao river is the westernmost identified paleochannel connecting the Kuang river with a paleo-Ping river. The paleochannel is now unrecognizable. While a section still exists as an irrigation canal 5 to 10 meters wide in Mae Faek and Mae Nong Han alternating with natural meanders 15-25 meters wide, the Khao river disappear in the suburban environment in a series of 1-2 meters wide canals and drainage. One of these drains still carry the name of Khao river and ends a few hundred meters from the current Kuang river. The Kuang river itself is now artificially diverted south but was flowing towards Chiang Mai in the past.
Figure 3. Identified paleochannels of the Ping river for the last millenium in the Chiang Mai - Lamphun basin (Teo, 2018).
The case of Mae Chaem
Mae Chaem river is a main tributary of the Ping river that does not directly concern Chiang Mai since the confluence of the two rivers is in Doi Tao Lake. Specific topographical conditions in the Mae Chaem basin allow a relatively precise record of past major floods as the Mae Chaem enters the Ob Luang gorge. While a major increase in flood volume in the Ping river does not increase substantially the water level, in a slot canyon with bare rock as river bed, the correlation between the size of a flood and the water level is very strong. The Ping river used to have a similar setup in the Ping gorge but it is now flooded since 1964 with the building of the Bhumibol dam and part of the Mae Ping N.P.
In the Mae Chaem, historical records of floods show an average peak at 421.8 m3/s, similar to the Ping river with the most recent maximum measured on the 13th of July 2001 at 4 am with +7.98 meters of flood waters equivalent to 794 m3/s, again, similar to the largest floods in the Ping river. A flood in 1960 gave values measured at 1030 m3/s by a water level station and 980 m3/s, on sediment records in the canyon. Based on this data, it became clear that some time around 1900 (1889-1908), an extreme flood occurred, carrying wood debris and archeological artifacts that were lodged into caves so high in the canyon that a flow of 2420 m3/s has been inferred. Such extreme flood (2.4 times larger than the largest recorded flood) and the similarities between the Mae Chaem and Ping catchments, leave some uncertainty on what extremes can be reached as the Ping river passes through Chiang Mai. Additional thoughts on the matter are available in this section.