Environmental Technology: Potential of Merging Road Pavement with Stormwater Detention

This study stresses on the concept of multi-functional urban land use incorporating permeable pavement integrated with underground storage. Permeable pavement that is available in the market consists of pavers and a thick layer of course aggregates that store water. Contrary to the mentioned pavement, this study tries to replace the underlying storage with blocks of concrete detention cells. Stormwater permeates through the openings of pavers and flows into the detention storage underneath. Investigation of such application is carried out using the SWMM software. Performance of a single hollow cube pavement block (0.25m x 0.25m x 0.25m) is demonstrated here. The block is virtually subjected to the worst scenarios of extreme rainfalls over a non-stop time span of three hours. Modelling outputs point to encouraging benefits of the anticipated size and storage volume are capable of capturing stormwater up to at least one hour. Thus, the system is suggested to be effective in limiting stormwater, and subsequently, promoting road structure as multi-purpose infrastructure

Dual-system concept for stormwater control in commercial centre

This paper describes the stormwater characterization due to a dual stormwater detention system that is tailored for a commercial area. A commercial centre is known to have the area covered with two distinct land uses, namely the shop buildings and tarred road surfaces. Manipulating these land uses for more environmental-friendly urban stormwater management; a novel dual stormwater detention system is introduced within the buildings and roads. Using a case study of a simple one-row shop building, a detention system is proposed under the walkway in front of the shop lots and under the parking spaces in front of the same shops. Storm water management model (SWMM) version 5.0 is used to simulate three scenarios of drainage flow in the study site. Simulations of a single detention system of either under the walkway (Scenario 1) or parking spaces (Scenario 2) are carried out. Scenario 3 is a simulation of a dual system combining the previous two scenarios. Scenario 2 has a catchment of about 10% of the total commercial centre; Scenario 2 has about 20% and Scenario 3 has about 30%. It is found that Scenario 3, namely the dual system with the highest connected water contributing catchment produces the best stormwater control by lowering the post-development peak hydrographs by 1.5 times, thus achieving the nearest to the pre-development condition. The simulations also show that the two separate single detention systems are less effective than the dual system in this case study

Applications of GIS and remote sensing in the hydrological study of the Upper Bernam River Basin, Malaysia

Rising concern over the degradation of the environment, such as erosion and sediment loads, warrants the integration of the complex and dispersed geographical data sets. This paper describes the use of Geographic Information System (GIS) and remote sensing for assessing the impact of land use changes to water turbidity in multiple watersheds. In this study, necessary data sets representing land uses, hydrology, weather, soils, elevation, and surface characteristics were integrated in a GIS in tabular, vector and grid formats. The land use maps that were derived from Landsat-5 TM imagery using a combination of different classification strategies gave an average accuracy of 95 %. Results from data analysis had shown that there exists a close relationship existed between the extent of open area and sedimentation loading rate. However, the sediment loading rates were found to be non-linear ranging from 1.47 to 2.13 tonnes per millimeter of rainfall for each kilometer-square increase of open areas, depending on their location of open areas with respect to factors such as availability of sediment, soil type, slope length, and slope steepness etc

Dual-system concept for stormwater control in commercial centre

This paper describes the stormwater characterization due to a dual stormwater detention system that is tailored for a commercial area. A commercial centre is known to have the area covered with two distinct land uses, namely the shop buildings and tarred road surfaces. Manipulating these land uses for more environmental-friendly urban stormwater management; a novel dual stormwater detention system is introduced within the buildings and roads. Using a case study of a simple one-row shop building, a detention system is proposed under the walkway in front of the shop lots and under the parking spaces in front of the same shops. Storm water management model (SWMM) version 5.0 is used to simulate three scenarios of drainage flow in the study site. Simulations of a single detention system of either under the walkway (Scenario 1) or parking spaces (Scenario 2) are carried out. Scenario 3 is a simulation of a dual system combining the previous two scenarios. Scenario 2 has a catchment of about 10% of the total commercial centre; Scenario 2 has about 20% and Scenario 3 has about 30%. It is found that Scenario 3, namely the dual system with the highest connected water contributing catchment produces the best stormwater control by lowering the post-development peak hydrographs by 1.5 times, thus achieving the nearest to the pre-development condition. The simulations also show that the two separate single detention systems are less effective than the dual system in this case study

Examining the impacts of individual lot stormwater detention in a housing estate

This paper describes the Storm Water Management Model (SWMM) simulations of three individual lot stormwater detention systems under the car porches of houses. These three systems consist of ready-made modular units presumably fitted under 49 m2 car porches of 204 double-story terrace houses. The 37,032 m2 housing estate is calculated to have 75% of land covered with houses, 25% with roads and other infrastructures. The housing estate was subjected to 5-minute, 10-year Average Recurrent Interval (ARI) short-duration design rainfall. The model predicted that all three systems could reduce the peak runoff at outfall from 2.79 to 0.38 m3/s. It indicated that any of the system could cause 86% reduction of the runoff for the whole housing estate. In order to differentiate the performance of the three systems, the housing lot was further investigated. When Type 1 system (1.15 m high with 49 m3 per lot) was analysed by the SWMM model, only 8% of its storage volume was filled that highlights an over design. Type 2 system (0.3 m high with 6 m3 per lot) modelled at 84% while Type 3 system (0.3 m high with 9 m3 per lot), at 54%. The difference in heights between the systems explained the low percentage of filling for the Type 1 system. Comparing Type 2 and Type 3, concrete structure within Type 3 had only half of its volume filled. In this light, the Type 2 system made of polyethylene pieces was found the most efficient in lowering post-development peak runoff