I suggest reading Chapter 17 of Szabó, J., Dávid, L., and Lóczy, D. eds. 2010. Anthropogenic Geomorphology A Guide to Man-Made Landforms. Springer, Dordrecht.
This is a summary chapter on anthropogenic landscapes. I highly recommend at least skimming through other chapters of this book as well.
Academic papers
Hooke, R.L. 1994 On the efficacy of humans as geomorphic agents. GSA Today4, 217–225 download pdf
What moves more material - rivers, or people?
Del Monte, M., D’Orefice, M., Luberti, G. M., Marini, R., Pica, A., & Vergari, F. 2016 Geomorphological classification of urban landscapes: the case study of Rome (Italy). Journal of Maps12, 178–189. doi: 10.1080/17445647.2016.1187977
Anthropogenic impacts on the landscape aren’t new - in some places they’ve been happening for thousands of years.
Hupy, J.P. and Koehler, T. 2012 Modern warfare as a significant form of zoogeomorphic disturbance upon the landscape. Geomorphology157–158, 169-182. doi: 10.1016/j.geomorph.2011.05.024
It’s not just the everyday human activity which modifies the landscape.