EBTAG Annual Workshop and Field Trip
May 20-21, 2013

Ecotone, 1413 Second Street, Suite 5, Santa Fe, NM, 87505, jwjansens@gmail.com

A series of surface and groundwater studies in the La Cienega Area of the Lower Santa Fe River in Santa Fe County were conducted in response to a concern that wetlands in the area have been degraded due to a variety of human-caused stressors and ecological changes. A confluence of surface and groundwater flows in the study area has supported the existence of extensive wetland areas and several historical, acequia irrigation-based agricultural communities, wildlife corridors, and open space amenities. The studies aimed to improve the understanding of groundwater resources that sustain wetlands and springs in the area, and included mapping of 680.3 acres of wetland habitat, along with stream flow monitoring and investigations of local geology, groundwater levels, and groundwater chemistry. Independently, local students and non-profit groups also conducted studies in the Lower Santa Fe River area. While springs and seeps contribute to streamflow in the area, direct measurement of spring and seep flows is difficult because the area of discharge is diffuse. Future monitoring and additional study of streamflow in the study area is needed to better understand streamflow variations over time. Springs and wetlands in the La Cienega area are supported by a complex, three-dimensional groundwater system wherein groundwater discharge from multiple flow pathways in the Santa Fe Group regional aquifer sustains the wetland environment. The location of the wetlands is controlled by the geologic setting. The La Cienega wetlands water budget is dominated by groundwater inflow and surface water outflow, with seasonal water level and water storage fluctuations controlled by changes in evapotranspiration between growing and dormant periods. Wetland zones and stream valleys are areas of both discharging and recharging groundwater, which indicate that local hydrologic processes, such as bank storage during storm events and local recycling of discharged groundwater and surface flows, play an important role in wetland function. Chemistry, isotope, and age characteristics of groundwater verify that mixtures of multiple groundwater sources with distinct chemistries and residence times feed wetland zones east and west of Cienega Creek.