1st World Conference on Soil and Water Conservation Under Global Change (CONSOWA) will be held from June 12 to 16, 2017, Lleida, Spain and you can check the link below:
Yes, there an International Gully Symposium or Conference, held most years. I am unsure of availability of past conference proceedings. I have a few gully papers on my researchgate, but will see if I cannot find you an internet link.
Recently one Global conference was held in India from 7-10 March 2016 on Ravine erosion at RVSKVV, Gwalior, M. P. India. The website was www.grc2016.org/www.rvskvv.net.