California Institute for Energy and Environment (CIEE)

In Arizona, riparian areas are important because of the limited amount of water and rapid population growth, that leads to the need for better management of riparian areas. We use PATHDISTANCE spatial model, incorporating rivers, water bodies, slope and elevation to model the extent of potential riparian areas in Arizona. We examined the geophysical potential of landform, rock formation and soil type factors for four native riparian woody vegetation types: cottonwood/willow, conifer/oak, mesquite and mixed broadleaf. To identify the suitable area for afforestation with these native riparian tree species, we analyzed the geophysical potential across the shrub/scrub land cover class (NLCD 2001) for three elevation strata. Total area identified for afforestation was estimated per native riparian tree species and potential carbon sequestration for 20, 40 and 80 year periods was estimated based on field carbon data collected along the Lower Colorado River. The analysis showed that area suitable for afforestation with conifer/oak could sequester more than 4 million t CO2e after 80 years, while riparian areas suitable for growing cottonwood /willow, mesquite and mixed broadleaf species have greater sequestration capacity - 97 million, 98 million and 89 million CO2e, respectively, after 80 years.