Economic Incentives in Stormwater Management: A Study of Practice Gaps in Poland

Sustainable rainwater management is made possible, among others, by nationwide and local policies and regulations that create economic incentives. This article analyzes how existing economic instruments in Poland motivate property owners to make investments that manage rainwater on their own properties. Two types of investments were analyzed: bioswales as one of the lowest-cost green infrastructure measures in construction and operation, and the rainwater harvesting solution that uses rainwater to irrigate greenery. Simulation of this type of investment was undertaken in response to existing economic incentives-obtainable discounts of national and municipal rainwater drainage fees and municipal subsidy programs for rainwater management from three cities of different sizes selected from the Greater Poland province. Analyses were carried out for three types of development: different intensity, sealing of the land, and number of residents. The financial profitability of the investment was evaluated by determining the payback period, NPV, and benefit-cost ratio, taking into account the possible discounts in fees and investment subsidies in the variant analyses. It was shown that the incentive function of national fees for rainwater drainage is low, and that the incentive function of municipal fees and subsidies is higher, depending on the design of the fee (rates and discounts) and subsidy (directions and level of subsidies) systems.