ESSM News & Events 2017 Science Supporting Society: Dr. Srinivasan's EPA Water Quality Modeling Efforts Have National Impact Over the last several years ESSM professor Dr. Raghavan Srinivasan has been working with USEPA office of water, water quality staff in Washington to parameterize and calibrate the Soil and Water Assessment Tool (SWAT) for the 48 contiguous states. The objective has been to create a centralized, web-based, and cost-effective system to analyze the effects of policy, social, and environmental change on water quality. The name of the system is the Hydrologic And Water Quality System (HAWQS) (http://epahawqs.tamu.edu). On April 20, Dr. Srinivasan presented the first of two webinars organized by USEPA water quality modeling workgroup (https://www.epa.gov/tmdl/tmdl-modeling). This first webinar focused on the SWAT model and its utility for water policy assessment, including examples of its past use at both agricultural and urban nonpoint source pollution at watershed and river basin scales in the US. He closed by introducing the HAWQS platform and responding to questions from webinar participants. The two-hour presentation attracted over 1,200 registrations and over 600 participants (largest number of registrations and participants in this webinar series), including EPA staff; state and local water resources professionals; consulting company professionals; University faculty, researchers and graduate students; and staff from environmental NGOs. Over 50 webinar participants immediately signed up as new HAWQS users. A future webinar will describe the HAWQS platform in greater detail, describing how use of the HAWQS platform reduces by 90% the time and effort needed to conduct standard EPA assessments of the effects of proposed policies and anticipated land use and environmental changes. Together, the two webinars are components of EPA’s nationwide rollout of HAWQS and should substantially reduce the cost of water quality policy assessments in the US.