Soldiers threw grenades into the water to stun fish, and the concrete they cracked was concrete their own regime had forced villagers to build. That is the short, ugly history of the first attempt to control the Chinit River - a diversion structure and a main canal with head regulators, raised in the Kampong Thom countryside under the Khmer Rouge, then knocked about by the men who were meant to be guarding it. The river runs on regardless, gathering 5,649 square kilometres of central Cambodia and delivering it, eventually, to the Tonle Sap.
Measured at the gauge at Kampong Thmar, where the catchment upstream covers 4,130 square kilometres, the Chinit averages 44.1 cubic metres per second. That average is close to meaningless. The recorded maximum is 329 cubic metres per second and the recorded minimum is 3.34 - a hundredfold swing between the river of the rains and the river of the dry months, which is to say two entirely different rivers wearing the same name.
The climate that produces this is monotonous in everything except water. Temperatures barely move across the year: an annual mean of 27.8 degrees, dipping only to 26.2 in December and rising to 29.8 in March. Rain is the variable. About 1,590 millimetres falls annually, nearly all of it between April and October, while evaporation claws back roughly 1,455. Nothing in the basin is dramatic in elevation - the high point reaches 288 metres at Phumi Chrach, and the lake it feeds sits barely above sea level. Three-quarters of the catchment is still under forest, and 14.8 percent is paddy.
In 1971 engineers drew up a multipurpose scheme for the whole valley - irrigation, flood control, fisheries and power - with a command area of 48,000 hectares across the districts of Santuk and Baray. A dam at Phnom Takho, controlling 3,770 square kilometres of catchment, would impound 500 million cubic metres gross and 391 million usable, feeding canal systems down both banks. A pumping station at Kampong Thmar would water a further 7,600 hectares. The power station was deliberately modest: 4.5 megawatts on a net head of 16.3 metres, sized for rural electrification and lift irrigation rather than for a national grid.
It was a reasonable plan for a country that was about to be taken apart.
Parts of it went in anyway, between the 1970s and the 1980s. The main diversion structure was completed, and the main canal with its head regulators, and the labour that placed them there was forced. The Khmer Rouge held Cambodia from April 1975 to January 1979 and treated hydraulic works as an article of faith, moving populations out of the cities and organising them into work brigades to dig canals and raise embankments at speed. Between 1.5 and 2 million Cambodians - around a quarter of the country - died in those years, of execution, starvation, overwork and disease. The people who shifted earth for the Chinit canal were farmers, teachers, shopkeepers and children, put to work by a state that had decided what they were for.
What became of the works afterwards is its own small indictment. Some of the structures were subsequently damaged by regime soldiers throwing grenades into the water to fish - the same men, on the same canal, destroying in an afternoon what had cost other people months. The canal outlasted the government that built it, in poor condition, and waited.
The rebuild arrived in 2003 as the Stung Chinit Irrigation and Rural Infrastructure Project, funded to the equivalent of 23.8 million US dollars by the Cambodian government, the Asian Development Bank, the Agence Francaise de Developpement and the beneficiaries themselves. Its opening phase targeted 12,000 hectares of new development, rehabilitation of about 7,000 hectares already worked, and a further 2,000 hectares under dry-season irrigation.
Over six years the project spread well beyond water, building or improving 150 kilometres of rural roads and six markets, reworking drainage, and running agricultural extension services, with farmers organised into Water User groups rather than simply handed a canal and left to it. By 2007 three communes and 24 villages in a single district had seen the benefit. Resettlement was handled in three phases - the irrigation and drainage corridors, the reservoir area, and the Otchork tributary - and a 2008 Asian Development Bank report judged all three satisfactorily implemented while noting that longer-term income restoration for the people moved was still running and would need monitoring after the project closed. That candour is worth something. Households displaced for a canal are usually the last line of any report, if they appear at all.
The Chinit is one of five large tributaries of the Tonle Sap system whose drifting larvae and fry have been netted and counted to work out how Cambodia's fish actually move. Seventy-one species in seventeen families have been recorded in the river. The surveys turned up something odd: each tributary carried its own distinctive assemblage, except that the fauna of the Chinit and the Stung matched one another exactly.
Life on the banks still follows the water. Wet-season rice dominates, including floating varieties that lengthen their stems to keep pace with the flood, while dry-season rice is confined to about a tenth of the cultivated area. White corn, green beans and tobacco go in on higher ground. Boats are small and few, since the draft will not take anything serious - villagers use them to fish and to run produce to market, which has always been the whole of the point.
The Chinit River, also written Stung Chinit or Stoeng Chinith, is referenced here at 13.5375 N, 105.793 E in Kampong Thom province, central Cambodia, and drains a 5,649 sq km catchment into the Tonle Sap. From the air the river is a dark, tightly meandering thread through an almost featureless plain; its appearance changes completely with the season, running bank to bank between April and October and shrinking to a chain of pools by March. The irrigation works are the clearest man-made feature - straight canal lines and head regulators cutting across the natural meander pattern near Kampong Thmar, plus roughly 150 km of rural roads built or improved after 2003. Recommended viewing altitude 2,000-5,000 ft AGL to read the canal geometry against the river; the Tonle Sap lake to the south-west is the region's dominant navigation feature, and Route 6 crosses the basin. Nearest operating airports are Siem Reap-Angkor International (VDSA), roughly 130 km west-north-west, and Techo International at Phnom Penh (VDTI), roughly 190 km south. Expect dry-season haze from crop burning February to April and heavy convective activity with reduced visibility May to October.