EFFECTIVENESS OF SELECTED LOW IMPACT DEVELOPMENT (LIDS) FOR SUSTAINABLE STORMWA TER MANAGEMENT IN FAST - URBANIZING RESIDENTIAL AREAS

Abstract

The  global  trend  of  urbanization  has  led  to  the  widespread  conversion  of  natural  land  cover  to impermeable surfaces. This, in turn, is hindering water infiltration and exacerbating runoff from precipitation.  This phenomenon  has  detrimental  effects  on  the  natural  environment  and  water quality. To address these issues of stormwater generation, this study employed the Storm Water Management  Model  (SWMM)  in  conjunction  with  Map Window  Geographical  Information System (GIS) v4.X, a hydrologic data software for data, visualization, editing, and integration with other  modeling  tools  to  simulate  the  impact  of  various  Low  Impact  Developments  (LIDs)  on mitigating stormwater in the study area. The study area was divided into six sub-basins within the GIS environment and imported into SWMM to assess the effects of selected LIDs, including green roofs, rain gardens, vegetative swales, and permeable pavements. The SWAT model was used to predict  water  flow  in  the  Malete  watershed  and  surface  runoff.  The  study  identified  areas susceptible  to  erosion  and  categorized  them  as  low,  moderate,  severe,  and  extreme.  The  results showed  that  permeable  pavements  exhibited  the  highest  reduction  rate,  reducing  stormwater  by approximately 50% across all sub-basins, while green roofs showed the lowest reduction rate of only  0.003%.  Regional  calibration  was  implemented,  revealing  a  significant  correlation  of  71%between simulated and observed flows in the study area. The findings of this study can serve as avaluable  decision-support  tool for  stakeholders  and  authorities  when  selecting  appropriate  LID practices to mitigate the urban impact of stormwater generation.   Keywords: Low Impact Development (LIDs), Malete, MapWindow GIS, MWSWAT, Soil Erosion, Stormwater, SWMM