Grass Swale Research Articles

Systematic evaluation of swale length, shape, and longitudinal slope with simulated highway runoff for better swale design.

Swales are a low-cost, conveyance and treatment system to manage roadway runoff, but available design guidance is limited. Eight grass swales were constructed in Raleigh, North Carolina, USA, to systematically evaluate the effects of design factors: length, shape, and longitudinal slope under two different storm sizes. Water from an onsite reservoir was used to generate synthetic runoff and simulate flow through the swales. Inflow volume, total suspended sediment (TSS), nitrogen, phosphorus, and four total metals (copper, lead, zinc, and cadmium) were tested with simulated levels representing highway runoff. Efficiency ratios were used to estimate the reductions in inflow volume, pollutant concentrations, and mass loads. Swale length, shape, longitudinal slope, and storm size significantly influenced runoff volume reduction. The longer (30m) trapezoidal swale constructed on the flatter (1%) longitudinal slope provided maximum reductions in sediment and heavy metal concentrations during small-medium storms. Larger storms had modestly reduced pollutant and volume mitigation. Effluent nutrient concentrations generally exceeded the influent exporting nitrogen and phosphorus from all swale configurations. Significantly better pollutant load reductions were provided by the longer swales for all pollutants, except dissolved phosphorus. Therefore, to optimize swale function, designers could maximize the swale length to the greatest extent practicable, particularly when swales receive inflow from end-of-pipe systems draining roadway surfaces. The trapezoidal cross-section was superior to the triangular cross-section for stormwater treatment. Proper vegetation establishment and maintaining optimal grass height are key to proper swale functioning.

Urban Stormwater Phosphorus Export Control: Comparing Traditional and Low-impact Development Best Management Practices.

Data from the International Stormwater Best Management Practices (BMP) Database were used to compare the phosphorus (P) control performance of six categories of stormwater BMPs representing traditional systems (stormwater pond, wetland basin, and detention basin) and low-impact development (LID) systems (bioretention cell, grass swale, and grass strip). Machine learning (ML) models were trained to predict the reduction or enrichment factors of surface runoff concentrations and loadings of total P (TP) and soluble reactive P (SRP) for the different categories of BMP systems. Relative to traditional BMPs, LIDs generally enriched TP and SRP concentrations in stormwater surface outflow and yielded poorer P runoff load control. The SRP concentration reduction and enrichment factors of LIDs also tended to be more sensitive to variations in climate and watershed characteristics. That is, LIDs were more likely to enrich surface runoff SRP concentrations in drier climates, when inflow SRP concentrations were low, and for watersheds exhibiting high impervious land cover. Overall, our results imply that stormwater BMPs do not universally attenuate urban P export and that preferentially implementing LIDs over traditional BMPs may increase TP and SRP export to receiving freshwater bodies, hence magnifying eutrophication risks.

A Modified Manning’s Equation for Estimating Flow Rate in Grass Swales under Low Inflow Rate Conditions

As green infrastructure has evolved, grass swales have become integral components of stormwater management. Manning’s equation is commonly used to describe the hydraulic characteristics of grass swales. However, due to flow loss from infiltration, grass swales often deviate from the assumptions of Manning’s equation, potentially leading to significant errors in grass swale flow rate calculations. In this study, we systematically investigated changes in flow rates in grass swales under various constant inflow rate conditions. The results indicated that the suitability of using Manning’s equation to estimate flow rate in grass swales varies with inflow rate. At an inflow rate of 3.00 m3/h, the discrepancy between the measured and the estimated flow rates by Manning’s equation was the smallest, ranging from −0.24 to 0.19 m3/h. At lower inflow rates (1.00 to 2.00 m3/h), Manning’s equation underestimated the flow rates by 0.16 to 0.47 m3/h; at higher rates (4.00 m3/h), it overestimated the flow rates by 0.01 to 0.61 m3/h. Considering infiltration losses as the primary cause of these errors, we proposed an improved Darcy’s formula for estimating the infiltration rates in grass swales, along with a modified Manning’s equation for more accurate flow rate calculations. The modified Manning’s equation provides enhanced accuracy in calculating flow rates in grass swales compared to the traditional version.

A holistic analysis of Chinese sponge city cases by region: Using PLS-SEM models to understand key factors impacting LID performance

Sponge city is a national sustainable stormwater management program proposed by the Chinese government to deal with urban water issues (e.g., flooding, poor water quality) brought on by climate change and urbanization. Various strategies for sponge city construction are required since environmental constraints differ regionally across the country. To identify regional variations, reveal the inner links between externalities and design elements in sponge city construction, and offer practical suggestions, efforts in two directions are made based on the data of 68 sponge city cases around China: 1) discussing design parameters of four Low Impact Development (LID) facilities, including bioretention cell, permeable pavement, grass swale, and sunken green space, under four regionalization maps of hydrologic, climatic, landform and soil texture factors, and 2) building a holistic Partial Least Squares-Structural Equation Modelling (PLS-SEM) model illustrating the relationship between local characteristics, LID system design, and LID system performance in sponge city construction. The results show that: 1) rainfall and landform factors have great impact on LID facilities design, as their depths tend to be higher in water rich areas and coastal areas. 2) LID types and areas are positively influenced (+0.745) by the total area and permeable portion of a project, while the LID system performance (water quantity and quality control) is negatively impacted (−0.407) by the rainfall amount and clay fraction. 3) comprehensive LIDs choice instead of single LID facility shows more significant effect on improving LID system performance. It is recommended to establish different design standards and assessment indexing systems tailored to local environment when constructing sponge city projects.

Assessment of the Implementation of Sustainable Stormwater Management Practices in Asian Countries

Numerous efforts have been undertaken by Asian countries to mitigate the adverse effects of urbanization on stormwater management. However, traditional stormwater systems have become overwhelmed due to extensive development, resulting in excessive runoff and frequent floods. As a result, it is crucial to urgently adopt sustainable stormwater management practices (SSMPs) to effectively control water quantity and quality. The goal of this study is to assess the viewpoints of stormwater practitioners regarding green roofs, rainwater harvesting systems (RHS), grass swales, rain garden/bioretention systems, and porous pavement using a SWOT analysis. This was accomplished by distributing questionnaires and evaluating previous studies. The survey showed that participants mostly agreed with the strengths, weaknesses, opportunities, and threats factors related to the chosen SSMPs. Overall, the respondents favoured the implementation of green roofs and grass swales. Further assessments were conducted on these practices in other aspects, confirming that green roofs are the most preferable SSMP for implementation in Asian countries.

Comparisons of Retention and Lag Characteristics of Rainfall–Runoff under Different Rainfall Scenarios in Low-Impact Development Combination: A Case Study in Lingang New City, Shanghai

An increasing focus has been given to stormwater management using low-impact development (LID), which is regarded as a “near-nature” concept and is utilized to manage and reduce surface runoff during the rainfall–runoff process. According to the hydrological monitoring data, we evaluated the retention and lag characteristics of rainfall–runoff in LID combination under three rainfall-intensity scenarios (light–moderate, heavy, and torrential rainfall) in Lingang New City in Shanghai. LID facilities have been constructed for three years in the target study area, including rain gardens, retention ponds, green parking, porous pavement, and grass swales. The average runoff retention was 10.6 mm, 21.3 mm, and 41.6 mm under light–moderate, heavy, and torrential rainfall scenarios, respectively, and the corresponding runoff retention rate was 72.9%, 64.7%, and 76.1% during the study period. By comparing rainfall, runoff retention, runoff retention rate, cumulative rainfall, and lag times, it becomes evident that the ability to retain runoff can be greatly improved in the LID combination. The average runoff retention was significantly enhanced by nearly two times and four times under the heavy and torrential rainfall scenarios compared to the conditions under the light–moderate rainfall scenario. Furthermore, the lag time from the end of rainfall to the end of runoff (t2) and the lag time between the centroid of rainfall and the centroid of runoff (t3) showed a significantly negative correlation with rainfall intensity. Meanwhile, t3 presented an incredibly positive correlation with rainfall duration. In this study, the LID combination demonstrated superior benefits in extending the duration of runoff in rainfall events with lower rainfall amounts, and demonstrated significant overall lag effects in rainfall events with longer durations and lower rainfall amounts. These results confirmed the vital role of the LID combination in stormwater management and the hydrologic impact of the LID combination on rainfall-induced runoff retention and lag effects. This work has provided valuable insights into utilizing LID facilities and can contribute to a better understanding of how runoff retention and lag characteristics respond to different rainfall intensity scenarios.

Determination of Grass Swale Hydrological Performance with Rainfall-Watershed-Swale Experimental Setup

High urbanization adversely affects the hydrological behavior of watersheds. Therefore, different stormwater management strategies have been put forward to mitigate these negative effects. Grass swales are one of the environmentally friendly practices that are widely used today as an alternative to traditional infrastructure systems to reduce the peak flow rates, increase infiltration, and the time of concentration. The determination of the effective parameters on the hydrological characteristics of grass swales plays an important role in identification of proper design criteria. To this end, hydrological experiments were conducted by designing a grass swale module and integrating it into a large-scale rainfall-watershed-swale (RWS) experimental setup. The potential effective parameters (rainfall, soil, grass type, drainage area, and grass height) on the hydrological performance of the grass swales were tested with six different swale configurations by the controlled laboratory experiments. Experimental results show that swales decrease the peak flow significantly. In addition, hydrological performance of swales decreases with the increase in rainfall intensity or rainfall duration. Moreover, the soil and grass type have a significant effect on the peak flow reduction and drainage performance of the swales.

Hydrodynamic characteristics of grass swale runoff in Guanzhong area of Loess Plateau, Northwest China.

Grass swale has been widely used in sponge city construction, which can effectively improve the urban ecological environment. To explore the regulation mechanism of runoff in grass swale, runoff scouring experiment was carried out to study the hydrodynamic characteristics of runoff and the distribution of cross-section velocity under the combined conditions of five slopes (1%, 2%, 3%, 4%, 5%) and five scour flows (20, 30, 40, 50, 60 L·min-1). With the increases of flow rate and slope, flow velocity, Reynolds number and Froude number all increased gradually, while the Manning roughness coefficient and Darcy-Weisbach friction coefficient decreased gradually. The velocity (V) could be expressed as a power function V=0.3387Q0.555S0.6601 of flow rate (Q) and slope (S). The variation ranges of Reynolds number and Froude number were 1160.95-6596.82 and 0.17-1.21, respectively. The runoff flow patterns were all turbulent. The flow pattern was greatly affected by the slope. When flow rate and slope were small, they had great influence on friction coefficient. Under the experimental conditions, the Darcy-Weisbach friction coefficient was negatively correlated with Reynolds number. The velocity distribution of cross-section showed symmetrical distribution on both sides of the center. The maximum velocity point was located at the center of water surface. With the increases of flow rate and slope, the velocity contours of cross section gradually became dense and the gradient of the velocity change increased. Our results provide a theoretical basis for the design, application and hydraulic calculation of grass swale in the construction of sponge cities in loess areas, and reveal the runoff regulation mechanism by analyzing the hydraulic characteristics of grass swale runoff.

Infiltration capacity in urban areas undergoing frequent snow and freeze–thaw cycles: Implications on sustainable urban drainage systems

Sustainable Urban Drainage Systems (SuDS) promote environmental protection and climate resilience. SuDS implementation in cold climates faces concerns of impaired hydrological function due to infiltration-reducing frost. The goal of this research was to assess the seasonal variations in infiltration and how different surface covers prevalent in and near coastal cities respond to frequent rain-on-snow and freeze–thaw cycles. A total of 28 constant head infiltration measurements were conducted over a period of 28 months in Urridaholt in Gardabaer, Iceland (64° 4′18.46″ N, 21° 54′37.11″ W) in a grass swale, lupine, and barren terrains. All test locations exhibited infiltration-inhibiting frost in winter, whose severity increased with frequent snow and freeze–thaw cycles. The grass swale resisted structural deformations resulting from frost, which was attributed to the high near-surface porosity within the intertwined root layer and the high drainage capacity of the underlying soil. The sparsely vegetated lupine and the barren area experienced severe frost heaving and cracking, and soil structural collapse which led to bypass flow upon thawing. The non-vegetated site had 30 to 50 times lower infiltration during winter (19 mm h−1) compared to the grass swale and lupine field (630- and 890-mm h−1, respectively), and twenty times lower during summer and fall (45 mm h−1 vs. ∼ 1000 mm h−1). The study concludes that frequent warming and cooling renders soils particularly vulnerable to frost. Vegetation plays an instrumental role in maintaining the hydrological functions of SuDS in winter. Therefore, the greening of urban centers is an important step towards climate resiliency. Plant selection and SuDS design criteria need to account for cold climate hydrological performance. In that regard, plants that limit sunlight and fully shed their vegetation in winter, such as the invasive lupine, can potentially contribute to frost formation and increase runoff generation.

A Multi-Index Evaluation System for Identifying the Optimal Configuration of LID Facilities in the Newly Built and Built-up Urban Areas

Intensifying urban stormwater runoff and pollution caused by urbanization and climate change threatens property and lives in cities around the world. Low-impact development (LID) is an effective approach to improve urban flood resistance, but there is a lack of quantitative evaluation criteria to determine the best scenario in the newly built and built-up urban areas. In this study, based on the Fuzzy Comprehensive Evaluation method (FCE), a multi-index evaluation system is established to quantify the LID performance for the environment, technology, economy, and society. For overcoming subjective arbitrariness, the Criteria Importance Though Intercriteria Correlation (CRITIC) and Analytical Hierarchy Process (AHP) methods are used to evaluate the weight of each evaluation index. The proposed method is demonstrated for the Xi’an City, China. Results show that the integrated configuration of green roof, infiltration pavement and grass swale has the best comprehensive efficiency under the proposed method. More specifically, the allocation of different LID combinations in the newly built area can effectively manage the flooding in this area. However, the comprehensive efficiency of increasing the diameter of the storm sewer is optimal in the built-up area. The increased pipe diameter can discharge more rainwater through the urban storm sewer and mitigate overflow. A multi-index evaluation framework beyond the traditional subjective evaluation standard is established, which can quantitatively evaluate the effectiveness of LID facilities. The proposed quantification evaluation method can provide an efficient recommendation for sponge city construction and evaluation.

Hydrologic performance of grass swales in cold maritime climates: Impacts of frost, rain-on-snow and snow cover on flow and volume reduction

Sustainable urban drainage solutions (SuDS) are a diverse set of design options that mitigate floods and improve water quality. Grass swales are the sole component of SuDS that transports runoff over long distances to downstream recipients. A deeper understanding of the performance of grass swales in different winter conditions is important in order for cities to achieve a greater climate resiliency. The goal of this study was to assess the impacts of frequent rain-on-snow, and freeze–thaw cycles on the hydrologic performance of grass swales. A total of 63 field synthetic runoff experiments were performed in a 5.8 m long section of a grass swale in the Urriðaholt neighborhood, Gardabaer, Iceland over 18 months. A three-fold reduction in peak flow attenuation was observed in winter (avg. 13%) compared to summer (avg. 38%) for hydraulic loadings ranging between 19 and 131 cm/h. The reduction in the performance of the swale was primarily due to frost formation and secondarily due to snow. The frequent rainfall, snowmelt, and rain-on-snow events elevated the soil water content and rendered the swale media susceptible to frost formation. The formation of pore ice within the 5 cm soil horizon led to a considerable reduction in soil porosity, which negatively affected the infiltration capacity, and shortened runoff lag times. Snow affected the performance by concentrating the flow in narrow channels, which reduced the effective area of infiltration, but also led to longer lag times and stored a portion of the runoff water within its pack. Despite the deterioration in the swale’s efficiency in winter, infiltration was observed in all synthetic runoff experiments, indicating that frost was either porous/granular, or heterogeneous in nature. The swale served its purpose to moderately reduce runoff peaks and volumes, especially for small and medium events. This research highlights the importance of effectively draining infiltration-based systems in cold climates to avoid the adverse effects of low temperatures.

Performance Assessment of Field-scale Dry Grass Swale with Shallow Substrate Layer

A field-scale dry grass swale with impermeable bottom and shallow substrate layer was built in Shanghai, where the groundwater table is very high, to avoid groundwater pollution caused by runoff infiltration. The underdrain pipe of the facility was up bended to avoid outside water flowing backward because local ground elevation is very low. Performance of the facility under the actual precipitation conditions was evaluated in the rainy season of 2019. The average runoff volume reduction is 39.4%, and the peak flow is reduced effectively when rain intensity is lower than 8.0 mm ·h-1. Influent mass load reduction of TSS, COD, TP, and TN are 95.4%, 83.1%, 90.0%, and 57.7%, respectively. Wood chips in the substrate layer and the saturated zone are effective for denitrification during the wet and dry periods, respectively. Hydraulic loading rate and antecedent drying period are the main factors affecting denitrification. Improved influent quality combined with the storage volume supplied by the local urban river network could meet the goal of annual runoff volume reduction and annual pollution load removal in districts with high groundwater levels.

Investigating the public health risks of low impact developments at residential, neighbourhood, and municipal levels

Low Impact Developments (LIDs) employ a series of vegetative techniques to retain rainfall close to the site of origin. Although LIDs offer sustainable runoff management, these infrastructures can be considered a risk to public health due to the presence of pathogens in the runoff and human exposure to contaminated water held in and transported by LIDs. The objective of this study is to examine the disease burden of Gastrointestinal illness (GI) from exposure to LIDs at the residential, neighbourhood, and municipal levels. The authors conducted a meta-analysis of literature on three water features: (1) harvested rainwater obtained from LIDs, (2) surface water, and (3) floodwater. A set of 32 studies were systematically selected to collect values of risks of infection and expressed as the disease burden, i.e. disability adjusted life years (DALYs). The results showed that the percentage of GI illness exceeding the health guidelines were high for harvested rainwater, i.e. 22% of annual disease burden exceeded the WHO guidelines (0.001 DALYs/1000 persons), and 2% exceeded the US EPA guidelines (5.75 DALYs/1000 bathers). Among the six exposures for harvested rainwater, exposure to spray irrigation, exceeded US EPA guidelines whereas; five exposures, i.e. flushing, hosing, daily shower, spray irrigation, and children playing, surpassed the WHO guidelines. Considering LID treatment, the values of annual disease burden from all the selected barriers were below US EPA guidelines however, these values exceeded the WHO guidelines for three barriers i.e. water plaza, grass swale, and open storage ponds. These findings provide a broader perspective of the disease burden associated with LIDs and emphasise to consider the type of exposures and required treatment barriers for developing LID infrastructures in urban areas.

Design of low impact development in the urban context considering hydrological performance and life‐cycle cost

AbstractThe pressures on water system are increasing in cities. Rapid urbanisation caused by booming population leads to more impervious area and less infiltration, with the consequence of larger runoff volume and higher flood risk. Launched in 2014, the low impact development (LID), an important part of Sponge City in China initiative, invests in projects that aim to restore the water cycle in the urban area. A comprehensive understanding of the performance of LID measures at watershed scale under different rainfall scenarios and life cycle costs is necessary. The objectives of this study are to assess the hydrological performance and to identify the optimal LID design by using SWMM model and life cycle cost (LCC) method. This study found that LID practices, including bioretention, grass swale, and permeable pavement, showed good performance on urban storm mitigation at watershed scale under different rainfall scenarios. Furthermore, the rates of surface runoff reduction were largely insusceptible to the change of rainfall volume and duration. Regarding the cost‐effectiveness, the priority was grass swale > bioretention > permeable pavement in the study area. The optimal LID scenario was the combination of these three types of LID. The proposed approach can help the decision‐makers to determine the preferable LID plan suitable for the local communities.

Best management practices for agricultural nonpoint source pollution: Policy interventions and way forward

AbstractBest management practices (BMPs) are the tools which are adopted to run any activity while inflicting least negative impacts on the surrounding environment. Since, water pollution is one of the most important issues in today's world; it is indispensable to discuss the activities which are deteriorating its quality. Although, a number of treatment technologies and methods are in place for treating the point sources of pollution, there is a need to address nonpoint sources of pollution. There are many successful practices which are capable of curtailing the impacts of nonpoint source pollution, if adopted. In this paper an attempt has been made to evaluate the performance and trade‐offs of various management practices to address the issues of agricultural nonpoint source pollution. Nevertheless, there is a dearth of guiding principles which can pave a way for adoption of these practices. Therefore, an attempt has also been made to explore the aspects of policy formulations along with emphasizing the factors which can lead to adoption/ non‐adoption of such practices.

Nitrogen Removal Efficiencies from Road Runoff by Dry Grass Swales with a Shallow Substrate Layer

To investigate nitrogen removal efficiencies and mechanisms from road runoff by dry grass swales with a shallow substrate layer, we constructed six dry grass swale columns with different structures and media composition. In order to enhance the nitrogen removal efficiencies during the whole process, fermented woodchips were added into the substrate layer, and saturated zones were established. Semi-synthetic road runoff was used as the influent water. The influent and effluent quality were analyzed, and the change in volumetric water content and ORP of the media were monitored. The results showed significant nitrogen removal by these columns under unfavorable conditions. The range of the average removal rate of TN by the dry grass swales with saturated zones was 67%-78%. The nitrogen removal process mainly occurred during the wet period of the substrate layer. The saturated zones enhanced nitrogen removal efficiencies during the dry period, and also promoted the quick establishment of anoxic conditions in the substrate layer during the wet period. The water-holding transition layer with organic matter was effective at providing a carbon source for denitrification in the saturated zone, and for avoiding the leaching of pollutants caused by organic decomposition.

The influence of external conditions on runoff quality control of grass swale in Beijing and Shenzhen, China

Abstract This study focused on the effects of external conditions on the performance of grass swales installed to improve stormwater runoff quality. Four grass swales in Beijing and Shenzhen with different underlying surface characteristics, antecedent dry weather period (ADWP), transport within the grass swales, and rainfall characteristics, were compared during 16 rainfall events in Beijing and six in Shenzhen, and were evaluated over two years. The results revealed that the impervious fraction of the catchment's surface below the swales influenced inlet pollutant concentrations, resulting in variations in their efficiency. ADWP, transport within the swales, and rainfall characteristics all had important effects on their efficiency in removing pollutants. With high pollution loads, long ADWP, and concentrated influent, the swales reduced pollutant concentrations significantly, particularly suspended solids.

Measurement and conceptual modelling of retention of metals (Cu, Pb, Zn) in soils of three grass swales

Grass swales are important elements of the urban green infrastructure that convey and attenuate urban runoff and improve its quality mostly through stormwater infiltration into, and retention of conveyed pollutants by, swale soils. The retention of metals by grass swales was addressed in this study investigating the enrichment of swale soils by three common traffic-related metals: Cu, Pb and Zn. Three swales of various characteristics (L1, L2, L3) were selected for study and their soils were sampled by coring the top 30 cm and dividing the cores into 5 cm thick layers. Cumulative metal burdens were compared to those modelled by the proprietary StormTac Web model, which estimates annual loads of specific constituents for the given land uses and stormwater treatment. The comparisons of measured (MBm) and simulated (MBs) metal burdens retained by swales showed that the measured values exceed the simulated ones, as described by average ratios MBs/MBm = 0.64, 0.50 and 0.59, for swales L1, L2 and L3, respectively. The measured burdens were calculated after subtracting the native soil metal concentrations, assumed equal to those found in the deepest sampled layer, 25–30 cm below the surface. The results suggest the feasibility of assessing performance of grass swales by modelling metal (Cu, Pb, Zn) retention by swales, however for older facilities considered for rehabilitation, the simulated results should be supplemented by soil chemistry sampling.

Implementation of the “sponge city” development plan in China: An evaluation of public willingness to pay for the life-cycle maintenance of its facilities

Urban stream syndrome, including urban waterlogging, flood risk, water shortage, water pollution and ecological restoration, are major challenges that cause potential risks to human beings. Recently, the sponge city construction (SCC) initiative in China has received extensive attention because it aims to systematically solve all of these urban water-related issues for a city. To date, little research has focused on the life-cycle operations, maintenance requirements and low public awareness of sponge city facilities (SCFs; e.g., rain gardens, green roofs, grass swales, and pavement greenbelts), which are challenges facing the development and sustainability of the SCC initiative. The aim of this study is to explore (i) the willingness to pay (WTP) for the life-cycle maintenance of SCFs and its determinants and (ii) the public's perceptions and attitudes towards the SCC initiative. We conducted a questionnaire-based survey combined with contingent valuation in three pilot sponge cities and then applied a two-phase logistic model and Tobit model to estimate the WTP of the respondents and the factors influencing the WTP. The results show that 76% of the respondents agreed to pay for life-cycle maintenance of SCFs, and the median amount of WTP was 16.57 CNY (2.53 USD) per month. Important factors influencing WTP include respondents' perceptions of the efficacy of the SCFs, concerns regarding the waterlogging risk and support for the SCF construction plans. The findings of this research extend our knowledge of the public's perceptions of and attitudes towards the SCC initiative and suggest that public contributions could serve as a crucial and feasible funding source for the life-cycle maintenance of SCFs.

Assessment of Storm Water Quality in Grass Swale by Using Sand Filter Media: a Case Study at UTHM Campus

Urbanization in Malaysia has contributed to the increased of volume runoff to the drainage system. SUDS (Sustainable Urban Drainage System) / MSMA (Manual Saliran Mesra Alam) has been implement in Malaysia within several of components. Hence, swale is one of the designed and suggested by SUDS or MSMA in order to control the quantity and quality storm water runoff. The present study aimed to determine the quality of storm water runoff in swale and to analyse storm water runoff treatment using sand column as a part of filtration process. Water quality parameters tested included COD, BOD5, DO and TSS. The samples was test with sand column on D30, D60, D90 and DMIX. The results revealed that sand column improved the water quality by 4% to 80%. In conclusion, the sand column can be used to improve the storm water quality and can enhance the natural habitat.