Six watershed models were calibrated for the purposes of determining High Pulse Count (HPC) Coefficients. The HPC coefficients are used in the computation of the Hydrologic Conditions Index (HCI). The goal of the study is to produce generalized coefficients that can be used to compute existing and potential HCI values for watersheds in Western Washington.

An extensive gage analysis was conducted on multiple watersheds to determine characteristics that alter watershed performance. By deriving proper watershed coefficients, HCI (Hydrologic Condition Index) and HPC (High Pulse Count) values, hydrologic modelers, developers, and researchers can determine the effectiveness of their analysis to better understand watershed performance. Different performance coefficients were determined for 5 watersheds (2 of these watersheds were combined for an average). The five watersheds include Quilceda + Woodard AVG, Chuckanut, Little Bear, and Issaquah. These coefficients were plotted against a variety of factors to determine correlative results and provide suggestions to jurisdictions.