Environmental researchers, modelers, water managers, and users require access to high-performance computing (HPC) resources for running data and computationally intensive models without being an HPC expert. To address these challenges, we have developed a web-service oriented gateway to HPC storage and computational resources. This gateway software (that we have named HydroGate) is a CGI based http web service that takes input via HTTP methods then transmits commands to the HPC system using SSH in a secure manner. The gateway abstracts away many details and complexities involved in the use of HPC systems including authentication, authorization, data and job management – transferring the data back and forth as well as creation, monitoring and scheduling of the jobs without installing any third-party software on the HPC systems. The web services we have developed may be called from a web server, or desktop client. The contribution of this study is the realization of the gateway service exposing an interface to the client applications that require access to the resources and services on the HPC centers in a secure and straightforward manner. The design and implementation are described, and the computational experience gained while developing the gateway is reported.