*Legal and Economic Aspects of Stormwater Management*

The adoption of alternative approaches to storm-water management bears an implicit economic impact on land development scenarios and water resource protection. Studies have been carried out, showing that the impact of LID and similar practices on property value is quite complex and variable. While this impact may be compensated by appropriate taxation policies, it reduces externalities due to avoided pollution [37].

Through the implementation of the Water Framework Directive into Polish law (Polish 'Water Law'), an obligation to manage stormwater runoff according to sustainable development rules came into existence [38]. Rainwater should be retained as much as possible at or near the location where precipitation occurred, through the use of surface or underground retention, and in-ground infiltration. Pursuant to the Polish Act, the "discharge of rainwater or meltwater into waters or into water facilities, contained in open or closed rainwater drainage systems for the discharge of atmospheric precipitation or into collective sewage systems within the administrative boundaries of cities" is part of "water services". Regardless of legal obligations related to discharge, financial obligations also exist. As provided for in Art. 389 IP, for this discharge it is necessary to obtain a suitable permit and abide by payment of fees to the service operator.

In the USA, a similar situation exists: The Water Quality Act of 1987 mandated the implementation of a comprehensive program to address stormwater runoff. Since no specific funding provision was established, municipalities introduced various fees in order to fund stormwater projects, effectively implementing a separate local taxation system. Other countries, like Canada, the United Kingdom, Germany, and Australia, have similarly introduced stormwater charges [39,40]. Communities currently use a combination of instruments: some introduced user fees to provide dedicated funding to "stormwater utilities" (separated from wastewater utilities), notwithstanding the complexity of identifying who pays and benefits for what, since drainage systems are often interconnected. Alternate funding methods include local bonds for infrastructural improvements, developer extension fees (capital costs shared among new developers), impact fees (based on mitigation costs of new developments' impact), special assessment fees, property taxes, and stormwater user (i.e., service) fees. User fee schemes could provide an equitable, dedicated source of funding, with charges commensurate with the cost of service, but they are not always applicable. Stormwater utility fees are considered more efficient and environmentally sustainable, allowing long-term planning and solutions, at the political cost of high visibility. Unlike other water cycle related fees, these could be reduced by stormwater credits for introducing best management practices (BMPs), such as those described.

In European countries, stormwater fees have been introduced for many years: in most German Lands, fees are calculated based on the impervious surface area. In Hamburg, for example, it is calculated according to the total costs attributed to the impervious area connected to the public sewer, and currently amounts to 0.73 €/m<sup>2</sup> impervious area [41]. In Italy there are no specific stormwater management fees so far. The cost of water services is covered under the formula of an "Integrated water tariff" paid to the local sewer operator, which takes care of all the aspects of water services from supply to collection and treatment, based on metered water consumption.

In Poland, the issue of stormwater fees foresees a water service fee, due for discharge of rainwater or snowmelt. The purpose is to encourage users to rationally manage water and limit pollution, as well as cover costs associated with drainage and facilities for its treatment. Fees consist of a fixed and a variable component: the former, sometimes referred to as "subscription" fee, depends on the maximum allowable rainwater discharge specified in the water permit. The base fee is PLN 0.75/m<sup>3</sup> (about 0.17 Euro) yearly, but if water retention devices with capacity >30% of annual runoff from the area are installed, it is reduced tenfold. In areas covered by combined sewer systems, the fee represents the cost of sewage collection. In areas with separate sewers, the fee is based on the volume of collected runoff or on the impervious area. The latter could range from 0.31–7.06 PLN/m<sup>2</sup> (about 0.07–1.63 Euro/m<sup>2</sup> ) [42].

In addition, Polish Water Law sets conditions for runoff drainage from industrial areas. In the case of areas greater than 3500 m<sup>2</sup> , a variable fee is applied if more than 70% of the surface is excluded from biologically-active areas (Article 268.1) as shown in Table 1. The fee is also assessed on all real estate located in areas not served by sewers. This applies to all real estate meeting the cited criteria, including large-surface commercial sites (e.g., supermarkets, warehouses), residential estate, office buildings, and housing communes.


**Table 1.** Variable stormwater discharge fees for industrial areas in Poland.

\* 1 PLN 0.2278 € (average between October 2019 and October 2020). This exchange rate will be used in all subsequent cost figures exposed in the paper.

In 2003, the city of Pila pioneered the introduction of a stormwater fee, quickly followed by other towns (Ostrow Wielkopolski, Nysa, Bielsko-Biala, Poznan, Biala Podlaska and Boleslawiec). Today, almost 95% of Polish town have implemented stormwater fee structures.
