The tall-grass prairies, wetlands and forests that dominated the Iowa landscape have been replaced by annual row-crops and grass pastures that occupy more than 90 % of the landscape today. Because of these changes water reaches the streams and gullies much faster and has led to incised streams and an extensive growth of gully networks. Stream and gully banks are major contributors of the nonpoi...

Introduction: The discovery of abundant, geologically recent gullies on Mars in Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images [1] has led to numerous studies examining potential mechanisms for recent fluid or fluid-rich surface processes [e.g., 1-2]. The process or processes involved in Martian gully formation provide important insights into Martian geologic and volatile history. ...

Introduction: The latitude dependent distribution [1-3] and non-uniform orientations [4-8] of young gullies on Mars suggest that their formation and modification are controlled by the activity of volatiles at or near the surface. Given the relative abundance of gullies and Mars' current thermal environment, CO 2 and H 2 O are the most likely candidates for contributing to gully evolution. Conte...

Introduction: Current temperature and pressure conditions on Mars suggest that liquid water is unstable at the surface with respect to boiling and freezing. However, gully features, generally consisting of alcoves , channels, and debris aprons and existing in a band at mid latitudes mainly in the southern hemisphere with a possible preference for pole-facing orien-tations [1, 2], suggest liquid...

Introduction: Gully features were first observed in the images taken by MOC in impact craters, south polar pits and large martian valleys [1], tending to midlatitudes [2]. HiRISE imagery supports the conclusion that the gullies were formed by fluvial erosion [3], but the source and composition of this fluid is unclear. The superposition of the gully aprons over aeolian features, e.g. dunes, sug...

Figure 1. Left: Gully system in the ADV, consisting of alcove, channel and fan; wind-blown snow has collected in topographic traps (alcove, channels); summer melting causes flow and erosion/deposition. Right: Gully system on Mars. Transient streams and gullies in the Antarctic Dry Valleys: Geological setting, processes and analogs to Mars J. W. Head, D. R. Marchant, J. Dickson, J. Levy, and G. ...

     It is widely known that the development of gullies causes the loss of a great amount of soil and can be considered as one of the principal causes of geo-environmental degradation. The study area of the present research is located in the eastern shores of Urmia Lake. This study sought to evaluate the rate of growth and effective factors on the area’s gully dynamic over a year. To achieve th...