Tijuana River Valley Comprehensive Protection and Rehabilitation Act of 2017 This bill directs the U.S. Army Corps of Engineers to carry out a comprehensive protection and rehabilitation program to enhance the physical infrastructure in both the United States and Mexico to prevent flooding and wastewater, sewage, trash, and sediment spills in the Tijuana River Valley, including carrying out coordinated restoration and protection activities that enhance the infrastructure. Grants and technical assistance must be provided under the program to state and local governments, nonprofit organizations, and institutions of higher education, in both countries. In addition, the Corps of Engineers must develop a feasibility and technical assistance plan for updated wastewater infrastructure and flood preparedness in the river valley. Using the systems of the International Boundary and Water Commission, United States and Mexico, the Department of State must establish the Transboundary Waterway Alert System, an updated and online system to protect U.S. citizens from undue and avoidable harm from wastewater, sewage, trash, and sediment spills and flooding for each major waterway along the U.S.-Mexico border. The State Department must notify Mexico, the cities of San Diego and Imperial Beach, and the county of San Diego upon the initial discovery of such spills.