This case study quantifies ecosystem services in several land use scenarios, relative to actual land use change, over a nine-year period. These scenarios were developed in an effort to maintain agricultural production while improving water quality and increasing water quantity in the watershed of the Miyun Reservoir—the only source of surface water currently available for domestic use in Beijing, China. Within the watershed, from 2000 to 2009, forest cover and urban area increased by 33% and 280%, while water provision and water purification services declined by 9% and 27%, respectively. Under a hybrid scenario of agricultural expansion with riparian grassland buffers, three services—water provision, water purification, and sediment retention—as well as agricultural production improved, compared with 2009 levels. Riparian grassland protection zones, seldom used in China, can effectively resolve trade-offs among multiple ecosystem services and are now being considered and implemented in several locations.