The ancient capital had no dependable source of water during the dry season, so a dam was constructed between the mountains of
Khao Kieo Ai Ma and
Khao Phra Bat Yai some three kilometers west of the city. Here, the water of mountain streams and rainy season precipitation was captured. The water was then conveyed to the city by the
Sao-Ho Canal, using a natural slope, where it was divided into four reservoirs:
Ngoen (silver),
Thong (gold),
So (lemon pond), and
Tra Kua (water spinach) inside the city walls. Another canal called
Mae Ramphan carried wastewater away to the east to the
Mae Nam Yom. In the mid-20th century, the dam was refurbished and expanded by the
Royal Irrigation Department and the
Fine Arts Department, while preserving its historic character. After renewal, its length is 487 meters with a thickness of eight meters and a height of 10.5 meters. Its storage capacity is around 400,000 cubic meters. ==References==