QUAL2K
Free
The classic river water-quality model — DO, nutrients and algae along a 1D stream network.
Water Quality & EnvironmentalDormantWater Quality Modelling
Excel & spreadsheet tools for water engineering
2 tools in the directory — every listing curated and classified by hand.
Virginia DEQ's official Excel workbooks for stormwater compliance via the Runoff Reduction Method.
Urban Stormwater & InfrastructureActiveSuDS & LID DesignStormwater Design