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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Restoration Ecology
HYDROLOGIC CONNECTIVITY OF NATIVE RIPARIAN FORESTS ALONG THE MIDDLE RIO GRANDE, NEW MEXICO.
J.F. Schuetz, J.-E. Cartron, M.C. Molles, Jr., C.N. Dahm, and C.S. Crawford. Department of Biology, University of New Mexico, Albuquerque, NM 87131
Over the past fifty years, volume and timing of the Rio Grande’s flow, including the annual flood pulse, have been altered due to damming and diversion of the river. As a result, the river is largely isolated from its riparian forest, or bosque, and the native cottonwood forest is aging, is not regenerating, and is being invaded by exotics. Restoration of native bosque may require restoring the annual flood pulse and thus the hydrologic connection between the river and its floodplain. To determine the current extent of hydrologic connectivity within a 160 km stretch of the Middle Rio Grande in New Mexico, we are investigating the relationship among river flow, groundwater depth and soil moisture at 4 flood and 4 nonflood sites. United States Geological Survey station data are used to monitor river flow at various locations within our study reach. Pressure transducers at each site measure groundwater depths throughout the year. Water content of the top 30 cm of soil at each site is measured using a water content reflectometer, and soil moisture from 25 to 100 cm below ground is measured using a neutron probe. Preliminary analysis of pressure transducer data suggests that flood sites are more connected the river than nonflood sites, and analyses of neutron probe data suggest that soil moisture is higher at flood sites. Results will help us inform policy-makers on potential tools, such as managed seasonal flooding in years with adequate water availability, to help restore the native bosque and the hydrologic connectivity between the river and its floodplain.
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