The lowest soil loss in catchment 玉 during 1989 1995 could be simply due to the fact that the gully plug鄄
ging structures filtered and retained the sediments carried by the runoff water on the upstream side. The periodic
deposition of sediments resulted in complete siltation on the upstream side of the structures up to the crest level
(Fig郾 1). The runoff water then starts flowing over the crest of the structures carrying the deposited sediments a鄄
long with it. The runoff water,which now falls over a greater height,becomes more erosive and causes soil erosion
on the downstream end of the gully plugging structures. This runoff otherwise would have flown smoothly( being
less erosive)in the absence of any gully plugging structure. The soil erosion caused by the runoff falling over the
structures is reflected from the depressions formed at the downstream end of almost all the structures installed in
catchment 玉. This process could have resulted in increased soil loss from the catchment treated with gully plug鄄
ging structures during the period 1996 2003郾 Kukal et al. (2006)observed that the siltation of the installed struc鄄
tures in the region is a common feature as these structures are generally installed in the highest鄄order gullies. The
runoff build up in the gully network takes place as usual through the lower鄄order gullies,with sufficient sediments
in it as is reflected from the amount of runoff which was not affected by treatments to the catchments. The gully
plugging structures thus installed in the highest order gully are not effective in checking the amount of runoff gen鄄
erated in catchment 玉,particularly during the later years(1996 2003)of their installation(Fig郾 1)as these struc鄄
tures become silted up to the crest height(Fig郾 2)and were not able to intercept runoff any more thereafter