Minimum Permeable Soil Area in a Sustainable Allotment Samuel João da Silveira 1 and Francisco Henrique de Oliveira 2 Abstract: Current scientific literature reinforces the observation that there has been an increase in frequent occurrences of floods in urban areas and emphasizes that the main reason for the increase of flooding is the reaction of the environment to the effects of anthropic action. Considering this scenario of flooding caused by man, this study aims to present a review of the literature on the influence of soil sealing, define sustainable allotment (SA) in line with the local behavior of the hydrological cycle, and propose the establishment of a technical requirement on the part of Brazilian municipalities of a minimum permeable area soil that should be left in each plot (plot territorial) of allotments that fits the sustainable concept. The research method was based on the observation of the behavior of some Brazilian cities [Antonio Carlos (SC), Biguaçu (SC), Criciúma (SC), Curitiba (PR), Ribeirão Preto (SP), São José (SC), and São José dos Campos (SP)] as well as other countries [Lisbon and Sintra (Portugal), Kitchener, Quebec, and Vancouver (Canada), and Liverpool (England)], especially in the areas of the infiltration minimum required to obtain a building permit. Research was also conducted to verify the respective regulations of maximum rates of land occupation and the minimum size defined for each lot, to avoid and/or minimize the occurrences of urban flooding. After a survey of normative data, six distinct simulations (minimum areas and average urban residential lots), were taken to verify the impact of the requirement of minimum area considered permeable. Finally, it is clear that for implementing a sustainable allotment, it is necessary to leave at least 25% of the area of permeable soil batch, resulting in a reduction of up to twice the volume of rainwater when compared with land in urban areas where the requirement does not apply. DOI: 10.1061/(ASCE)UP.1943-5444.0000162. © 2014 American Society of Civil Engineers. Author keywords: Flood; Rainwater; Soil sealing; Sustainable allotment; Sustainability. Introduction Currently, there are increasingly devastating effects of rainwater around the world. This can be seen in the study presented by Perry (2000), which reports on the 32 most significant floods in the United States throughout the twentieth century. Dividing this ob- servation period into equal intervals of 10 years, and determining the frequency of occurrences in each period, we reach the result presented in the graph in Fig. 1. Based on Fig. 1, it can be concluded that the frequency of flood- ing in the United States has been increasingly significantly over the past decades. This characteristic is not unique to the United States; Lee and Kim (2012) and Takasou et al. (2002) report that similar behavior has been occurring in South Korea, and Tominaga (2009) reinforces these observations that can also be observed in other countries and thus be well defined for Brazil. The rate at which these natural disasters are occurring is increasing. The current scientific literature, such as the GFDRR (2010), reinforces the observed increase in frequent occur- rences of floods through the research presented by Livingston and McCarron (1992), USEPA (1993), Bigarella et al. (1994), Arnold and Gibbons (1996), Center for Watershed Protection (2000), Whitford et al. (2001), Tucci (2008), da Hora and Gomes (2009), Prokop et al. (2011), and Lee and Kim (2012), among others. These authors emphasize that the main reason for the increased occurrence of floods is the reaction of the environment to the effects of anthropic action. Emphasis should be given to changing the course of natural drainage caused by urbanization, which may cause several impacts or changes in hydrological behavior. Factors primarily responsible for these effects include: 1. Soil sealing; 2. Artificiality of watercourses; 3. Construction of barriers to the flow; 4. Occupation of the floodplain area; and 5. Inefficient land planning in urban occupation, as they do not concatenate the data pertaining to territorial parcel/plot with a constructed area. Among these effects, this article effectively discusses the impact of soil sealing, which, according to Lee and Kim (2012), is signifi- cantly influenced by urban development. It is worth noting that soil sealing is directly linked to the coefficient of surface drainage and it varies according to the variables: surface (vegetation, soil, gravel, slope), soil (sandy, loamy, organic), temperature, and other of smaller representation (LIMA 2008). Based on these considerations, this research aims to present a literature review of the influence of soil sealing, to define sustain- able allotment (SA) in line with the local behavior of the hydrolog- ical cycle, and to propose a technical requirement on the part of municipal government, namely that a minimum area of permeable soil should be left in each batch of sustainable settlements. That last goal meets the indications of current research, in the conclusions presented by Fontes and Barbassa (2003), who reported the impor- tance of using the free areas of lots to avoid intensification of runoff through infiltration of water into the soil. In this context, Susilo et al. (2009) reinforces the potential benefits of water infiltration, 1 Federal Institute of Education, Science and Technology of Santa Catarina—IFSC Academic Dept. of Construction 950, Mauro Ramos Av., Downtown Area, Florianpolis, SC 88020-300, Brazil (corresponding author). E-mail: samueljs@ifsc.edu.br 2 State Univ. Santa Catarina—UDESC Center for Humanities and Education 2007, Benvenuta Madre Av., Itacorubi, Florianpolis, SC 88035-001, Brazil. E-mail: chico.udesc@gmail.com Note. This manuscript was submitted on August 21, 2012; approved on May 24, 2013; published online on May 27, 2013. Discussion period open until June 6, 2014; separate discussions must be submitted for indi- vidual papers. This paper is part of the Journal of Urban Planning and Development, © ASCE, ISSN 0733-9488/04014003(10)/$25.00. © ASCE 04014003-1 J. Urban Plann. Dev.