The Master Plan for the Sustainable Management of Rainwater in the Metropolitan Area of San Salvador (AMSS) was created with the fundamental objective of establishing the actions necessary for the proper functioning of rainwater drainage in the AMSS.
The work carried out consisted of drafting the referenced project for the Lamination Dams called “Colonia Luz”, “El Piro Aguas Arriba” and “El Piro Aguas Abajo”.
- Definition of maximum precipitation in 24 h from IDF curves defined at a rainfall station in the study area. Study for 5, 25, 50 and 100 years of return period.
- Hec-HMS pseudo-distributed hydrological modelling of the 55 km2 Montserrat Arenal basin, considering the intersection of the various streams and the possible location of lamination dams
- Soil Conservation Service (SCS) model for defining unit hydrograph and rainfall-runoff model (curve number, CN).
- Muskingum hydrograph propagation model.
- Definition of CN based on land use map from previous MARN studies.
- Determination of the drainage capacity of the channel from a two-dimensional hydraulic study with IBER at the control points.
- Calibration of the hydrological model.
- Determination of feasible reservoir solutions based on available volume at each proposed site. Lamination capacity and downstream effect within the Montserrat Arenal system. Optimization of the solution using Linear Programming using the SIMPLEX algorithm, implemented in the MS Excel sheet using the Solver function.
- The contribution of sediments to the different reservoir sites was analyzed based on the universal soil loss equation and the land characterization data available in the basin.
- A cost-benefit analysis based on the cost of infrastructure was carried out. Analysis of the real estate affected by the flood and different levels of danger, as well as the possible loss of human life.