Computational Hydraulics International (CHI) develops and supports technically advanced, professional software systems for stormwater, sanitary sewer and watershed modeling. PCSWMM, engineered by CHI in 1984, is a trusted, leading spatial decision support software for wastewater, watershed and stormwater management modeling. Incredibly easy to use and extremely comprehensive, PCSWMM is admired and trusted by over 5000 valued customers in more than 85 diverse countries.