The Sunnyhill Housing Cooperative, in Central Calgary, is a flat, poorly drained site with a long history of drainage problems.  Working with civil engineers, Mr. Amell developed a SUD design that works within the tight spatial constraints imposed by a long established multifamily residential site. Innovations in the design include the incorporation of rain gardens within useful socializing spaces that are being called “amphitheatre gardens”. Riparia also designed vertical flow biofiltration beds that rapidly collect water in order to reduce flooding of pathways and parking pads, then slowly filter and discharge to the underlying gravel aquifer.