The overall goal of the WRIA 1 Watershed Management Project is to have water of sufficient quantity and quality to meet the needs of current and future human generations. This goal includes the restoration of salmon, steelhead, and trout populations to healthy and harvestable levels, and the improvement of the habitat upon which fish rely. Since the inception of the Project in 1998, steps have been taken to achieve this goal, including the development of the technical information necessary to evaluate instream and out-of-stream needs. The goal of integrating hydraulic, hydrology and fish habitat models is to describe the relationship between weighted usable area and streamflow for species and life stage utilization throughout the year. In 1999, the Instream Flow Methods Conference achieved agreement among the invited experts on the most appropriate method(s) for estimating an accurate relationship between streamflow and fish habitat quantity and quality in Water Resources Inventory Area 1 (WRIA 1). Over the 2000 through 2004 period, sites where field data were to be collected were identified by consensus of the Instream Flow and Fish Habitat technical team members based on a number of factors including representativeness of the site, the availability of fish utilization data (e.g., spawner surveys, smolt traps), locations where instream flows were established by Ecology in 1985 (WAC 173-501), and management issues or where known conflicts over water use existed. The field data collection and analyses of the collected field data were conducted to implement the agreed upon most appropriate methods for estimating the relation between streamflow and fish habitat quantity and quality at 37 sites within WRIA 1 (Figure 1). After collecting hydraulic and fish habitat characteristics of these locations, Intensive and Rapid Assessment sites were incorporated into the hydrology model node structure used in the first implementation of the WRIA 1 Watershed Modeling using Topnet-WM (Tarboton 2007) as well as the second implementation focused on estimating the Lower Nooksack Water Budget (Bandaragoda et al. 2012). This work, Data Integration of WRIA 1 Hydraulic, Fish Habitat, and Hydrology Models, is intended to increase the usability of existing data and to help achieve the overall goals of the Water Resources Inventory Area No. 1 (WRIA 1) Watershed Management Project. No new modeling was performed as part of this technical project.