Capturing wetness for sustainability from climate variability and change in the Rio Conchos, Chihuahua, Mexico

This is study of the Rio Conchos Watershed, Chihuahua, Mexico. This study provides assessment of selected extreme wet events from reservoir overflow data within climate variability from analysis of climate indices, sea-surface temperatures, hurricanes, and nearby tree-ring indices in Chihuahua, Mexico. The treaty-delivery requirements as well as local sustainability through direct use or replenishment of additional water requires coordinated capture of these wet events. Most of these extreme wet events and related reservoir spills occur during the Monsoon and hurricane season and appear to be related to additional storms from these weather events. Increased East-Pacific Sea-Surface Temperatures and variability combined with doubling of hurricanes, are driving additional extreme wet events across northern Mexico with 26 overflow events occurring at the Francisco I. Madero reservoir since 1955 shortly after construction of the reservoirs in the Rio Conchos Watershed. Climate variability has become more extreme with these wet events and droughts dominated by decadal cycles largely coincident with Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation cycles. All climate indices exhibit multiple levels of cycles that are being further amplified by climate change and become cycles of opportunity for capturing additional water needed for sustainability. Supply and demand management requires capture, use, reuse, and replenishment plus additional infrastructure, changes in local governance, and changes in land-use and treaties. Coordinated operation and planning will facilitate use of variable water resources for enhanced sustainability as part of a broader Conjunctive Water Management framework within the Rio Conchos watershed subject to climate change and variability. • Climate variability is key to conjunctive water management and sustainability. • PDO and AMO influence wet periods and spill events significantly. • MAR and FloodMAR ensure proper management of excess surface water. • Transboundary water sharing should align with climate cycles and contributions. • Sustainability needs monitoring, governance, and infrastructure at various cycles.