Flow Accumulation (IMAGE) Washington University in St. Louis Caption An aggregate 'flow accumulation' model finds that nearly 75 percent of ancient Silk Road sites in the Inner Asian highlands fall along pathways (shown in red) that ancient Central Asian nomads likely used to move herds to prime summer pastures. Credit Illustration by M.Frachetti/ T. Bukowski. Usage Restrictions None 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.