Discussion of “Simple Estimation of Prevalence of Hortonian Flow in New York City Watersheds” by M. Todd Walter, Vishal K. Mehta, Alexis M. Marrone, Jan Boll, Pierre Gerard-Marchant, Tammo S. Steenhuis, and Michael F. Walter.

The article presents a discussion on the paper "Simple Estimation of Prevalence of Hortonian Flow in New York City Watersheds" by M. Todd Walter, Vishal K. Mehta, Alexis M. Marrone, Jan Boll, Pierre Gerard-Marchant, Tammo S. Steenhuis, and Michael F. Walter. The paper is a welcome contribution to the engineering literature, as it raises the issue of the process and pathway of delivery of water to stream. The paper examines critically the prevalence of Hortonian flow in the New York City watershed. The authors find Hortonian overland flow occurrence to be highly restrictive in terms of rain intensities and durations.