Assessing the use of exfiltration pervious pavements as a best management practice for storm water management for Lusaka urban

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Banda, Naphtallie
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The University of Zambia
Stormwater management is being justified as a fundamental line of consideration in achieving sustainable urban development. Lusaka urban experiences impacts ensuing from developments in form of urban floods. This study was undertaken in Lusaka urban to assess the use of a full exfiltration pervious pavement system as a best management practice for stormwater management. Based on the ICPI guidelines, the study involved a feasibility assessment to select areas supporting full exfiltration pervious pavements, construction of pervious pavements (PICP) in 3 sites, conducting infiltration tests on the constructed pavement systems and monitoring of water infiltrating below the pavement systems succeeding storm events for the study period. A t-test was used to compare significant differences and regression analysis was used for determining relationships. Key observations are that the central eastern part of the study area has soil physical characteristics supporting full exfiltration pavement systems under which the sites were selected. Infiltration rates on the installed pavement systems with 5mm spacers ranged from 774cm/hr. to 823cm/hr. The average depth of water estimated to have been contributed to the immediate unsaturated zone below the pavement systems through infiltration during each observed rainfall events ranged from 140mm to 211.4mm in 1100mm depth of soil. The study concluded that full exfiltration pervious pavement systems as a best management practice can be integrated with drainage networks for Lusaka urban to reduce floods ensuing from developments. The system will mimic natural environments which allow infiltration of stormwater to potentially contribute to groundwater. Key words: Stormwater, Best management practices, Pervious pavement, Exfiltration
Water quality management--Zambia , Watershed management--Zambia