HELIX Environmental Planning has prepared desktop environmental constraint analyses for segments of 16 potential high speed rail alignment corridors extending between the cities of Los Angeles and San Diego, including portions of San Diego, Riverside, San Bernardino, Orange, and Los Angeles counties. These analyses identified and assessed potential issues and constraints related to hazardous materials, biological resources, geologic hazards, land use, environmental justice, community facilities, noise, visual character, water resources/wells, floodplains and Section 4(f) resources. The constraint studies were based on data from sources such as Google Earth®; ArcGIS®; SanGIS; and multiple federal, state and local databases. From the identified potential issues and constraints, qualitative comparisons were provided for the associated segment options within each alignment. In addition, HELIX prepared quantitative desktop constraints studies for 18 alternative alignments extending between San Diego and Los Angeles, encompassing similar geographic areas as previously noted. These analyses were based on data sources including SANDAG; SCAG; and several federal, state, and local databases, with the results used to create quantified impact assessments for issues including land use, environmental justice communities, cultural resources sites, wetlands and biological resources/preserves.