Performance Of Low Impact Development Practices Research Articles

Evaluating the Performance of Low-Impact Development Practices in Mitigating Runoff Floods in the Kinyerezi River Catchments in Dar es Salaam, Tanzania

Evaluating the Performance of Low-Impact Development Practices in Mitigating Runoff Floods in the Kinyerezi River Catchments in Dar es Salaam, Tanzania

Spatial allocation of LID practices with a water footprint approach

Urban water problems due to stormwater have been aggravated by the higher frequency of high-intensity precipitation events and the increase of paved surfaces. However, with appropriate stormwater management practices, such as low-impact development (LID), stormwater can provide an additional urban water resources rather than cause damage. This study aims to apply a water footprint to location determination of LID practices in the urban area. The LID planning procedure was demonstrated with the highest population density region in Taipei, Taiwan. In order to improve the spatial resolution of LID allocation, the “first-level dissemination area” with 450 residents was used as a spatial unit. The performance of LID practices was then evaluated with the simulation using the Storm Water Management Model (SWMM). Three LID practices, rainwater harvesting systems, permeable pavements, and bioretention systems, were selected. After the water footprint accounting, ten sites were suggested for LID implementation. The runoff reduction rate reached up to 65 % by rainwater harvesting systems or at least 3 % by permeable pavements. This study provides a simpler and more effective approach to ways of integrating an urban water footprint into LID planning and stormwater management in urban areas.

A Multiobjective Spatial Optimization Model of LID Based on Catchment Landuse Type

Aiming to solve the problem of the low efficiency and single objective of low impact development (LID) layout, the objectives of stormwater control, water quality purification, and economic cost are selected to present the performance of LID practices. A novel method of evaluating urban runoff and pollutant concentration is put forward based on the land-use type of each catchment. Shenzhen City is selected as the study area, and three LID scenarios are designed and contrasted for an ideal solution according to their land-use type. The results show that the multiobjective optimization model based on runoff evaluation, pollutant simulation, and investment calculation can be more efficient and can be applied in other areas.

Evaluation of the effects of low-impact development practices under different rainy types: case of Fuxing Island Park, Shanghai, China.

The soil permeability and underground water level greatly affect the performance of low-impact development (LID) practices. Shanghai is located in the area of estuary and is characterized by its high groundwater level and low soil infiltration rate. The LID practices in Fuxing Island Park, Shanghai, including a bioretention cell, swales, a permeable pavement, and a combined LID practices were studied in the present paper. The performance of LID practices during the period of eight rainfall events was evaluated in terms of hydrology and water quality. Due to the detention of the LID practices, a significant delay between the peak rainfall and the peak surface runoff was observed. On-site tests show it is suitable for the applicability of LID in a rainy city with low soil infiltration rate and high groundwater level. Moreover, the Stormwater Management Model (SWMM) was also used to compare the hydrologic effects before and after these four LID practices application in the park. Results indicated the LID practices could effectively reduce the runoff volume and the peak flow in the park. Furthermore, the runoff water quality evaluation showed the pollutants were effectively removed by these four LID practices due to both runoff treatment and flow volume reduction. The bioretention system proved to be effective as a result of its larger facility area while the swales had the obvious reduction volume both per facility area and per catchment area.

Evaluating the Impact of Low Impact Development (LID) Practices on Water Quantity and Quality under Different Development Designs Using SWAT

The effects of Low Impact Development (LID) practices on urban runoff and pollutants have proven to be positive in many studies. However, the effectiveness of LID practices can vary depending on different urban patterns. In the present study, the performance of LID practices was explored under three land uses with different urban forms: (1) a compact high-density urban form; (2) a conventional medium-density urban form; and (3) a conservational medium-density urban form. The Soil and Water Assessment Tool (SWAT) was used and model development was performed to reflect hydrologic behavior by the application of LID practices. Rain gardens, permeable pavements, and rainwater harvesting tanks were considered for simulations, and a modeling procedure for the representation of LID practices in SWAT was specifically illustrated in this context. Simulations were done for each land use, and the results were compared and evaluated. The application of LID practices demonstrated a decrease in surface runoff and pollutant loadings for all land uses, and different reductions were represented in response to the land uses with different urban forms on a watershed scale. In addition, the results among post-LIDs scenarios generally showed lower values for surface runoff and nitrate in the compact high-density urban land use and for total phosphorus in the conventional medium-density urban land use compared to the other land uses. We suggest effective strategies for implementing LID practices.