CRWA's stormwater trading approach is based on a simple, interactive web-based design program and trading platform, which reduces owner costs associated with green infrastructure property retrofits, and increases compliance with stormwater regulation.
Stormwater runoff has overtaken wastewater effluent as the largest source of pollution to many rivers across the United States. Traditionally, the approach to reducing stormwater pollution and its associated flooding has been to establish standards for new development to keep things from getting worse, and at the very least, some improvements when a site is redeveloped. The expectation has been that over time all properties will be redeveloped, so gradually, rivers will be restored. Unfortunately, this approach isn’t working.
Redevelopment alone is not changing enough of the urban landscape to clean rivers, reduce flooding and build resilience to drought. There is simply too much urbanized area that mismanages rainwater. Reversing how rain and stormwater runoff are managed on existing developed properties, streets and parking lots is necessary in many cities. Yet uniform regulation of stormwater runoff is resisted, in large part because it creates significant uncertainty and results in highly variable owner compliance costs because site conditions differ widely.
To achieve necessary pollution reductions at the lowest possible cost, stormwater management controls should be built where conditions are best – where soils can easily absorb rainwater and plants are able to filter out pollutants effectively. Sites with constraints such as contaminated soils or bedrock should be left alone. To provide this type of efficiency, however, requires a framework that allows property owners to determine the least expensive way to meet their regulatory stormwater management requirements. While the idea of water quality trading –buying and selling pollution reduction credits – is not new, water quality trading markets have been slow to emerge because each trade requires cumbersome individual analyses.
Additionally, the process of property evaluation and cost estimates (based strictly on acres of pavement, for example) has been too coarse, too time-consuming, or too expensive to facilitate trading mechanisms. CRWA has been working on a stormwater trading approach based on a simple, interactive web-based design program and trading platform, which reduces owner costs and increases compliance with stormwater regulation.