Programme  Poster session 4  abstract 737


Author(s): André Luiz Lopes da Silveira, Geraldo Lopes da Silveira
PhD Student Institute of Hydraulic Research – IPH, Federal University of Rio Grande do Sul – UFRGS, CNPq Grant Holder – Brazil. Address: Barão do Amazonas, 1157/38, 90670-004, Porto Alegre – RS – Brazil, Telephone +55 51 33 08 63 27, Fax +55 51 33 08 75 0

Keyword(s): financing urban drainage, stormwater source control, contingent valuation method, developing countries

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Session: Poster session 4
AbstractUnplanned urbanization in developing countries has a negative impact on the hydrological cycle. In

Brazil and other countries, there has been discussion regarding the adoption of mechanisms for encouraging and

financing the reduction of this impact, using as reference charges for the urban drainage service. The aim of the

present study is to propose a methodology for financing the urban stormwater source control adapted to developing

countries. The method with comply with precepts of Low Impact Development (LID), which aims to affect

landscapes with hydrological functions by exhibiting a more natural behavior. The methodology proposed starts with

an analysis of the current hydrograph of urbanized areas, denominated the post-development hydrograph, and the

construction of a pre-development hydrograph in order to outline scenarios for reducing runoff volumes. These

reductions will be obtained by the introduction of distributed devices, designed and dimensioned according to the

LID, that permit infiltration and storage, which are hydrological processes that are lost during urbanization. Numeric

simulations of hydrological behavior of the scenarios established and the optimization (minimization) of the cost

function ensure cost-effective solutions. The scenarios will define fees for the proprietors of urban lots and charges

will be based on the production of runoff, that is, an alteration in the natural flow volume. Using the Contingent

Valuation Method (CVM), it is possible to determine the Willingness to Pay (WTP) and Willingness to Receive

(WTR) on the part of the proprietors of the lots. With WTP, possible scenarios are established that are financed by

direct fee charges. With WTR, a comparison is made with the cost reduction for the city obtained through the use of

source control by proprietors. In situations of poverty or a scarcity of financial resources, such as in Brazil and most

other developing countries, the WTR is higher than the WTP. Therefore, in order to encourage changes in behavior

on the part of proprietors, it could be more effective to stress that the fees are designed to reach environmental

goals. This type incentive is more adapted to the situation of societies that need to resolve issues regarding sanitation

infrastructure. The application of the methodology is expected to make evident the feasibility of the use of drainage

fees for the financing of sustainable methods of controlling the problems stemming from urbanization. The definition of

a drainage fee is both environmentally correct and socially just; through the definition of environmental goals, the onus

generated by proprietors is internalized regarding the particular use of the drainage system (equity). Furthermore, the

economic aspect is validated by means of social prospecting, making it viable through the strategy adopted (CVM).

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