Urban stormwater management is increasingly required to balance flood mitigation, water quality improvement, and sustainable water use. The Cornerstone Phase 1 Storm Pond P project in northeast Calgary demonstrates how stormwater reuse can be integrated into conventional wet pond design to support both landscape irrigation and wetland replenishment while meeting stringent regulatory discharge and water quality objectives. Storm Pond P services a 153.9 ha mixed residential and commercial catchment and was designed as a permanent wet pond with offline sediment chambers to achieve sediment removal targets exceeding 85% for particles ≥50 µm prior to discharge to Nose Creek. In addition to quantity and quality control, the system incorporates active reuse of stored stormwater to offset potable water demand and support downstream aquatic features. Stormwater reuse for irrigation is achieved through controlled pumping from the pond’s permanent storage zone between defined lower and upper normal water levels. Reclaimed water is used to irrigate approximately 15.3 ha of parks, sports fields, school sites, and landscaped open spaces, with irrigation demand and withdrawal rates governed by evapotranspiration, soil infiltration capacity, and seasonal operating rules. The reuse system is explicitly modeled within a continuous PCSWMM framework to evaluate long-term water balance performance and ensure compliance with watershed runoff volume targets. In parallel, stormwater is reused to replenish an adjacent constructed wetland (Wetland Q), providing ecological support and additional volume management benefits. Automated control rules regulate pumping based on pond water levels and seasonal conditions, ensuring wetland replenishment without compromising flood storage capacity. This case study illustrates how storm ponds can function as multi-purpose water infrastructure, integrating stormwater reuse, irrigation efficiency, and wetland sustainability into urban drainage systems. The approach offers a transferable framework for municipalities seeking resilient, climate-adaptive stormwater solutions that extend beyond traditional conveyance and detention objectives.
