Ancient Chinese Irrigation System (IMAGE) Washington University in St. Louis Caption Researchers have identified seven areas along the Mohuchahan Valley (MGK), where ancient irrigation systems once functioned. The current study focuses the MGK4 plot. Credit (Map: Courtesy of Archaeological Research in Asia) Usage Restrictions With permission from the journal Archaeological Research in Asia. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.