Waterfowl and wading bird use of potholes at the Potters Marsh HREP, Pool 13 Gent, R. 1997. Waterfowl and wading bird use of potholes at the Potters Marsh Habitat Rehabilitation and Enhancement Project Upper Mississippi River, Pool 13. Reprinted by U.S. Geological Survey, Environmental Management Technical Center, Onalaska, Wisconsin, October 1997. LTRMP 97-R021. 10 pp. (NTIS #PB98-105851) ABSTRACT Remedial measures have been used by the Environmental Management Program (EMP) to restore and enhance aquatic habitat at a variety of locations on the Upper Mississippi River System. While habitat modeling indicates a significant gain in habitat utility for riverine species, field verification of direct use of the newly created habitat by targeted organisms is rarely done. This project attempted to quantify waterfowl and wading bird use at a series of potholes created at Potters Marsh in Upper Mississippi River, Pool 13. Waterfowl consistently used the potholes during March July 1996, with nearly 80% of the use during the spring migration. Nesting and brooding activity in the vicinity of the potholes was minimal during 1996, possibly due to extensive flooding of the Potters Marsh area during the peak nesting period. Pothole construction method (mechanically excavated versus blasted with explosives) had little impact on total bird use, however 87% of observed Canada geese were located on blasted potholes. Zooplankton populations were significantly higher in the mechanically excavated potholes, possibly due to increased water depth at excavated sites. Submergent aquatic vegetation was sporadic and found only in mechanically excavated potholes while blasted potholes were characterized by floating beds of filamentous algae. KEYWORDS HREP, potholes, waterfowl brooding, waterfowl nesting