1. a Department of Hydraulic and Environmental Engineering , Federal University of Ceará , Campus do Pici, bl. 713, 60.451–970, Fortaleza, CE, Brazil E-mail:
2. b GeoForschungsZentrum Potsdam (GFZ), Section 5.4: Engineering Hydrology , Telegrafenberg, D-14473, Potsdam, Germany
3. c Institut für Geooekologie, Universität Potsdam , Postfach 60 15 53, D-14415, Potsdam, Germany