To develop a water allocation model for the Chao Praya Basin we needed to obtain a better understanding of how farmers obtain and use water. The statistical data about the region raises several questions; such as why in years with low water availability rice production is not affected much. Researchers from the Institute of Water Policy visited two farms in the western and central-eastern part of the Chao Praya delta.
The Chao Praya delta has an extensive and well-developed irrigation network consisting of large and small canals, gates and weirs that bring the water from the main river to the fields.
A sluice gate clogged by water hyacinth. Water hycinth is one of the fastest-growing invasive species and originates from South America. It causes problems in many parts of the world.
Water for household use is sourced from groundwater, filtered, and then pressurised using small water towers. For drinking purposes, the water still needs to be treated further or the villagers use bottled water for drinking.
The water for irrigation of fields is pumped from the canals using pumps that are connected to the engines of small tractors, which are also used for ploughing. Depending on the rainfall, farmers pump several hours a week and longer when fields are being prepared for planting.
The water is pumped into small canals in the fields. Most farmers in the area we visited have installed groundwater wells. If there is not enough water in the large irrigation canal, they can connect their pumps to the groundwater wells to irrigate their fields. Groundwater levels are quite shallow, at 3 to 4 meters, yet pumping from the large irrigation canal is cheaper and hence will be used first when available.
Farmers along the large irrigation canals usually have enough water, though those further away are more often faced with drought conditions. The Royal Irrigation Department has projects to improve flows to the more remote fields, such as building new, larger culverts.
The farmers in this area do not follow a specific cropping calendar and grow two to three crops a year. So fields in different growth stages can be seen. Due to low prices for rice, some farmers are trying to grow new types of rice, such as black rice, or focus on niche markets, such as growing pesticide-free rice.
We thank the farmers, staff from the Royal Irrigation Department and other departments and agencies for their time and willingness to talk with us.