Groundwater in the Tibet Plateau, western China

The Tibet Plateau in western China embraces a variety of hydrologic processes. Water cycling plays an unequivocal role in buffering or intensifying climate impact on water resources and ecosystems. Although much research has focused on climatic aspects, little is known about the subsurface component of the water cycle, particularly groundwater-flow patterns and recharge and discharge characteristics. This study shows that groundwater flow in the Plateau is driven and sustained by the topographic gradient and recharge at high elevations. Groundwater is recharged at the rate of approximately 100-200 mm/year. Groundwater discharge on the order of 10(-9)-10(-7) m/s occurs in valleys and fault zones, supplying baseflow to rivers and springs. Reliable recharge is critical for sustaining the water cycle and reduced recharge could diminish groundwater replenishment to rivers and springs, adversely impacting the ecosystems on the Plateau.