Interfaces between traditional urban drainage systems and water resources: case study – Rio Tavares and Morro das Pedras watersheds, Florianópolis, Brazil

Abstract

This study identified and systematized the interfaces between traditional urban drainage systems and water resources with the aim of providing decision-makers with the scientific and technical knowledge required to develop an integrated urban water management strategy. After the collection of technical documents on the sanitation infrastructure of the Rio Tavares and Morro das Pedras watersheds, in Florianópolis, Brazil, the stormwater drainage system of the region was mapped and the environmental characterization described, dividing the two basins into 6 regions for analytical purposes. The systematization of the documents resulted in a synthesis map generated by cross-checking the information regarding the current drainage system, the hydrography, and the vulnerability of the Campeche aquifer (DRASTIC and GOD methods), thus revealing the interfaces between stormwater management and surface and groundwater resources. The diagnostic phase identified the use of structural measures for the straightening and/or channelization of parts of the river. In the analyzed orthophotos, flooding points were observed downstream of the watersheds. The stormwater effluents are discharged, without any pretreatment, into the mangroves and sandbanks, or infiltrate through the drainage pipe, creating points of contaminant injection in the Campeche aquifer. This study suggests the creation of a unified database for the drainage network, hydrography and urban infrastructure, as well as the standardization of projects by means of sanitation, water resource, and stormwater management plans. and drainage systems are developed in order to assess the real impacts of urban drainage systems on surface and groundwater resources.

Use of geotechnologies in integrated assessment of urban drainage, water resources and urbanization

“…They were also interested in studying the vulnerability of the aquifer and proposing protection measures. GOD and DRASTIC methodologies were used for this work and was described in detail by Pacheco and Finotti [10]. In summary, GOD methodology is based on the evaluation of three parameters: groundwater occurrence (G), overall lithology (O) and depth to groundwater (D).…”

“…In the third phase, a synthesis map was developed, with the intersection of the information plans regarding the drainage network, the vulnerability of the Campeche aquifer and the location of the water resources. This map has allowed the identification of management conflicts related to water resources, arising from the lack of integration among managers, as presented by Pacheco and Finotti [10].…”

“…The range 0.8-1 comprises the one of extreme vulnerability values. The details of such methodologies and the vulnerability map were presented in Pacheco and Finotti [10]. The vulnerability map was integrated with other maps to build up the synthesis map shown in Fig.…”

“…of view, it forms the Santa Catarina Island, major sub-basin [14]. When the lagoon overflows and overlaps into the secondary bed, the water runs off through a channel southeast of the lagoon and between the dunes, forming swamps that slowly seep into the Riozinho river and reach the Campeche beach [10].…”

“…Riozinho do Campeche has its source in Morro do Lampião and receives stormwater and sewage effluents from important streets. This river has problems of Figure 4: Synthesis map of hydrography, vulnerability and urban drainage system [10].…”