STORM WATER BEST MANAGEMENT PRACTICES THAT MAXIMIZE AQUIFER RECHARGE

This article reviews and provides evaluation guidelines for six major storm water best management practices includingbioretention areas, grassed swales/fi lter strips, infi ltration trenches, porous pavement, rain barrels and wet detentionponds. A detailed table allows for quick and easy design comparisons, including a separate table which allows forsite specifi c cost comparisons. A logic diagram is provided as a basic tool for screening the most feasible managementpractice.

Representation of Agricultural Best Management Practices in a Fully Distributed Hydrologic Model:A Case Study in the Luoyugou Watershed

Agricultural Best Management Practices （BMPs） are effective ways to reduce agricultural nonpoint source pol ution from their source area to receiving water bodies. Characterization of BMPs in a watershed model is a critical prerequisite for evaluating their impacts on water quantity and water quality in a complex system. However, limited research has reported about the representation of BMPs in fully distributed models. This paper presents a stepwise procedure for representation of several BMPs and assessment of their hydrologic impacts with a ful y distributed model, SEIM （Spatially Explicit Integrated Modeling）. A case study is conducted in the 73 km2 Luoyugou watershed located in the Loess Plateau of China, where rainstorm erosion accounts for more than 60%of annual sediment load in average. Three BMPs are selected in this study including （i） conversion from farmland to forest, （i ） terrace, and （i i） no-til farming. These management practices are represented in the model through the alteration of model parameters characterizing their physical processes in the ifeld. The results of scenario assessment for a historical storm event showed that the maximum sediment reduction after terrace is about 97.3%, the average sediment reduction after no-till farming is about 9.5%, and the average sediment reduction after conversion from farmland to forest is 75.6%.

Evaluation of non-point source pollution reduction by applying Best Management Practices using a SWAT model and QuickBird high resolution satellite imagery

This study evaluated the reduction effect of non-point source pollution by applying best management practices （BMPs） to a 1.21 km^2 small agricultural watershed using a SWAT （Soil and Water Assessment Tool） model. Two meter QuickBird land use data were prepared for the watershed. The SWAT was calibrated and validated using dally streamflow and monthly water quality （total phosphorus （TP）, total nitrogen （TN）, and suspended solids （SS）） records from 1999 to 2000 and from 2001 to 2002. The average Nash and Sutcliffe model efficiency was 0.63 for the streamflow and the coefficients of determination were 0.88, 0.72, and 0.68 for SS, TN, and TP, respectively. Four BMP scenarios viz. the application of vegetation filter strip and riparian buffer system, the regulation of Universal Soil Loss Equation P factor, and the fertilizing control amount for crops were applied and analyzed.

Sedimentation retention basin utilization for best management practice

Approaches to the artificial impoundment and theoretical design of sedimentation retention basin are reviewed with particular attention to best management practice(BMP) to control agriculture and surface runoff. Sediments retention basins are the small version of farm pond used where a criteria of farm pond is not met. Such basin traps the pollutants and suspended solids prior to entry into streams and lakes. The study is focused with special reference to the assessment and control of non point source pollution(NPSP) from the sub basin area of Tai Lake in the Xishan County of Wuxi City of China. The author suggested two different approaches to conduct this study including theoretical design for sedimentation retention basin and computation of flow, sediment transport and deposition during the artificial impoundment of retention basin for BMP's utilization. Theoretical design will provide a useful function as a first line defense against the movement of sediments and transport of pollutants into the Tai Lake while the assessment of sediments deposition will help to make its proper use and periodic cleanup.

Hydrological simulation approaches for BMPs and LID practices in highly urbanized area and development of hydrological performance indicator system

Urbanization causes hydrological change and increases stormwater runoff volumes, leading to flooding, erosion, and the degradation of instream ecosystem health. Best management practices （BMPs）, like detention ponds and infiltration trenches, have been widely used to control flood runoff events for the past decade. However, low impact development （LID） options have been proposed as an alternative approach to better mimic the natural flow regime by using decentralized designs to control stormwater runoff at the source, rather than at a centralized location in the watershed. For highly urbanized areas, LID stormwater management practices such as bioretention cells and porous pavements can be used to retrofit existing infrastructure and reduce runoff volumes and peak flows. This paper describes a modeling approach to incorporate these LID practices and the two BMPs of detention ponds and infiltration trenches in an existing hydrological model to estimate the impacts of BMPs and LID practices on the surface runoff. The modeling approach has been used in a parking lot located in Lenexa, Kansas, USA, to predict hydrological performance of BMPs and LID practices. A performance indicator system including the flow duration curve, peak flow frequency exceedance curve, and runoff coefficient have been developed in an attempt to represent impacts of BMPs and LID practices on the entire spectrum of the runoff regime. Results demonstrate that use of these BMPs and LID practices leads to significant stormwater control for small rainfall events and less control for flood events.

Decadal Trend of Coastal Water Quality in Orange County Beaches and Management Efficacy at Improving Public Health Protection

Historical fecal indicator bacteria measurements （n = 125,000; 10 years） in Orange County coastal zone, an interface with urban watershed that is one of the most developed areas in the United States and source of highly polluted runoff discharges, have been compiled and analyzed. During the period from 2000 to 2010, fecal indicator bacteria concentrations in Orange County Beaches progressively increased （poor water quality） in the first half of the decade and progressively decreased （improved water quality） during the last half of the decade. Among all physical, chemical and environmental factors, 59%-74% of the variability in the fecal indicator bacteria concentrations in the coastal zone records can be attributed to seasonal and interannual variability in local rainfall, implying that stormwater runoff from the surrounding urban watershed is a primary source of fecal pollution in Orange County Beaches. These results suggest that efforts to improve water quality in Orange County Beaches and protect beach-goers from pollution will likely have greater efficacy during wet weather periods than the rest of the year. In addition, this study identified the effect of alongshore surf zone current on fecal pollution caused by coastal waves. The data and analysis presented in this paper provide a framework for evaluating the longer period water quality trend in the coastal area, and elucidate Best-Management-Practices that can improve public health protection by managing coastal water quality compliance with standards.

Field test of best management practice pollutant removal efficiencies in Shenzhen,China

This paper presents a study on the use of best management practices(BMPs)for controlling nonpoint pollution in the Xikeng Reservoir watershed located in Shenzhen,China.A BMP treatment train design,including a pond,a wetland,and a buffer strip placed in series was implemented at the reservoir location.A separate grass swale was also constructed at the site.Low impact development(LID)BMPs,namely a planter box and bioboxes,were used at the parking lot of the reservoir’s Administration Building.Samples were collected during storm events and were analyzed for total suspended solids(TSS),biochemical oxygen demand(BOD5),ammonia nitrogen(NH3-N),and total phosphorus(TP).The removal efficiencies of both BMP systems were evaluated using the Efficiency Ratio(ER)method based on the event mean concentration(EMC)data.In summary,the pond/wetland treatment train removed 70%–90%of TSS,20%–50%of BOD5,and 30%–70%of TP and NH3-N.The swale removed 50%–90%of TSS,30%–55%of BOD5,–10%–35%of NH3-N,and 25%–70%of TP.For the planter box and biobox,the ranges of removal rates were 70%–90%,20%–50%,and 30%–70%for TSS,BOD5,and ammonia and phosphorus,respectively.

Influence of climatic conditions,topography and soil attributes on the spatial distribution of site productivity index of the species rich forests of Jalisco,Mexico

This paper presents an approach based on field data to model the spatial distribution of the site productivity index （SPI） of the diverse forest types in Jalisco, Mexico and the response in SPI to site and cli-matic conditions. A linear regression model was constructed to test the hypothesis that site and climate variables can be used to predict the SPI of the major forest types in Jalisco. SPI varied significantly with topog-raphy （elevation, aspect and slope）, soil attributes （pH, sand and silt）, climate （temperature and precipitation zones） and forest type. The most important variable in the model was forest type, which accounted for 35% of the variability in SPI. Temperature and precipitation accounted for 8 to 9% of the variability in SPI while the soil attributes accounted for less than 4% of the variability observed in SPI. No significant differences were detected between the observed and predicted SPI for the individual forest types. The linear regression model was used to develop maps of the spatial variability in predicted SPI for the individual forest types in the state. The spatial site productivity models developed in this study provides a basis for understanding the complex relationship that exists between forest productivity and site and climatic conditions in the state. Findings of this study will assist resource managers in making cost-effective decisions about the management of individual forest types in the state of Jalisco, Mexico.

Potential of rooftop rainwater harvesting to meet outdoor water demand in arid regions

The feasibility of rooftop rainwater harvesting （RRWH） as an alternative source of water to meet the outdoor water demand in nine states of the U.S. was evaluated using a system dynamics model developed in Systems Thinking, Experimental Learning Laboratory with Animation. The state of Arizona was selected to evaluate the effects of the selected model parameters on the efficacy of RRWH since among the nine states the arid region of Arizona showed the least potential of meeting the outdoor water demand with rain harvested water. The analyses were conducted on a monthly basis across a 10-year projected period from 2015 to 2024. The results showed that RRWH as a potential source of water was highly sensitive to certain model parameters such as the outdoor water demand, the use of desert landscaping, and the percentage of existing houses with RRWH. A significant difference （as high as 37.5%） in rainwater potential was observed between the projected wet and dry climate conditions in Arizona. The analysis of the dynamics of the storage tanks suggested that a 1.0-2.0 m3 rainwater barrel, on an average, can store approximately 80% of the monthly rainwater generated from the rooftops in Arizona, even across the high seasonal variation. This interactive model can be used as a quick estimator of the amount of water that could be generated, stored, and utilized through RRWH systems in the U.S. under different climate conditions. The findings of such comprehensive analyses may help regional policymakers, especially in arid regions, to develop a sustainable water management infrastructure.

Wood Preservative Solutions for Creative and Sustainable Bridge Design and Construction

Timber bridges can provide an economical alternative to concrete and steel structures, particularly in rural areas where vehicle traffic is light to moderate. The wooden components of bridges have historically been preserved with either an oil type or waterborne preservative system to protect the wood from decay in order to maintain required performance standards for an extended period of time. The focus of this paper is to describe some of the key preservatives, research and case studies that support use of preserved wood, and some important steps to follow for the appropriate and safe use of preserved wood when the planned application will be in or over aquatic and wetland environments. A wealth of scientific information has been collected and analyzed that clearly suggests the use of preserved wood does not present a significant adverse effect on aquatic and wetland environments. This conclusion is based on two decades of empirical research and case study evaluating the environmental fate and effects of preserved wood, level of migration of contaminates into aquatic and marine environments, and the preserved wood environment. This is particularly true when risks are properly assessed on a project site, the appropriate preservative is selected and the wood is preserved to the Western Wood Preservers Institute＇s BMPs （best management practices）, along with properly installing and maintaining the preserved material. To assist with the assessment process, peer-reviewed risk assessment models for 11 commonly used preservatives have been developed that provide for streamlined data entry by users and allow for evaluation of a structure above and below water. A companion preliminary screening level assessment tool is also available. When these measures are properly utilized engineers, biologists and other responsible officials can be confident that the service life of the preserved wood components will more than likely meet the required performance standards in an environmentally safe manner for up to 50 or more years on a majority of timber bridge projects.

A Project Plan for Controlling of Nonpoint Source Pollution in China

Nonpoint source pollution is a major cause of remaining water environmental quality problems in China＇s main water bodies, especially is a potential danger for drinking water resource. But in China, nonpoint source pollution control is still at its early stage, many related programs and policies are absent, researches and practices of controlling NPS pollution are scarce. Projects based on BMPs, which were proved successful in controlling nonpoint source pollution in developed countries, are also increasingly utilized in China＇s nonpoint source pollution control. Designing a successful project includes 9 items such as identifying the water quality problems, stating the water quality problems, defining objectives and goals, obtaining funds, involving the community, cooperating and coordinating among agencies, outlining the critical and sensitive areas and so on.

A Review and Recommendations for Promoting Environmentally-Friendly Agriculture in Korea

The objective of this study was to provide a macroscopic evaluation review of environmentally-friendly agriculture （EFA） status and then suggest policy recommendations for promoting EFA in Korea. Amid considerable challenges, including food security, many small-scale farms with increasingly aged farm population and growing competition, agri-environmental indicators （AEIs） and EFA certificate performance shed light on the fact that the trend of the state of the environment reversed, albeit with room to improve. Identifying positive contributions to EFA made by target-oriented long-term EFA plans and the direct payment scheme, this paper suggests to enrich the agricultural information systems, a system approach to agri-environmental resource management, and make a transition toward the low inputs farming systems.

Spatial optimization of soil and water conservation practices using coupled SWAT model and evolutionary algorithm

Soil and water conservation practices have been extensively used in effective watershed management.The impact of each conservation practice is site specific and dependent on the implementation site in the watershed.In order to select cost effective placement of conservation practices with high impact,a large number of spatial combinations is needed to be compared.In this study,an optimization model framework is presented to find cost effective solutions for sediment yield and runoff control in the Fariman dam watershed in the Northeast of Iran.This was accomplished by integrating soil and water assessment tool(SWAT)for simulation of watershed hydrology and multi objective genetic algorithm(NSGA-II)for spatial optimization of soil and water conservation practices.The optimized solutions provided a trade-off between the two objective functions.The final Pareto-optimal shows that the impact of soil and water conservation practices on sediment yield is more than stream flow.The trade-offs between the objective functions show that the implementation of the median cost can lead to a significant decrease of 22.1%in the amount of sediment yield,and 10%in stream flow.Also,percent change achieved through median cost is very close to percent reduction with the highest cost.Results of low cost solution show that the vegetative practices are a suitable economic scenario for soil and water conservation.The introduced framework can be adapted as a suitable tool for selecting cost effective conservation practices in different regions.

BMP decision support system for evaluating stormwater management alternatives

Prince George’s County,Maryland,in the Washington D.C.metropolitan area has developed a best management practice decision support system(BMPDSS)to support analysis and decision making for stormwater management planning and design at both the site scale and the watershed levels.This paper presents a detailed description of the BMPDSS.A case study that demonstrates the application of the system is also included.The case study involves a Green Highway project located in a highly urbanized area within the Anacostia River watershed of the county.Several best management practices(BMP)such as bioretention,filter vegetative swale,porous paving,and landscape infiltration are proposed for reducing highway runoff and improving water quality.The BMPDSS is used to identify and evaluate various alternatives to determine the most costeffective types and combinations of BMPs that minimize the highway runoff pollution.

A validation of WEPP water quality routines in uniform and nonuniform agricultural hillslopes

Current watershed-scale,nonpoint source pollution models do not represent the processes and impacts of agricultural best management practices on water quality with sufficient detail.A Water Erosion Pre-diction Project-Water Quality(WEPP-WQ)model was recently developed which is capable of simulating nonpoint source pollutant transport in nonuniform hillslope conditions such as those with BMPs.However,WEPP-WQ has not been validated for these conditions,and prior validation work only eval-uated calibrated performance rather than uncalibrated performance,with the latter being most relevant to model applications.This study evaluated uncalibrated and calibrated model performance in two plot-scale,artificial rainfall studies.179 observations were compared to corresponding WEPP-WQ simulations of runoff,sediment yield,and soluble and particulate nutrient forms for both nitrogen and phosphorus.Uncalibrated validation results were mixed for the different field conditions,model configurations,and prediction variables.Nash-Sutcliffe Efficiencies for uncalibrated simulations of uniform conditions were generally greater than 0.6 except for soluble nitrogen predictions which were poor.Simulations of nonuniform conditions were generally'unsatisfactory'except for runoff predictions which were quite good(NSE=0.78).Performance was improved substantially for almost all endpoints with calibration.Some exceptions to this occurred because the objective function for calibration was based on log-space differences so as to more equally-weight calibration of unsaturated conditions that tend to produce lesser runoff volumes and sediment yields.Calibrated results for both uniform and nonuniform condi-tions were generally'satisfactory'or'good'according to widely accepted model performance criteria.

DEVELOPING MARKET-BASED INCENTIVES FOR GREEN BUILDING ALTERNATIVES

As the 4th most populous and 2nd fastest growing region of the U.S.,70%of Florida’s 16-million citizens reside along the coastline in areas served by shallow,fragile aquifers that have largely been destroyed by over-pumping and saltwater intrusion.Resulting wastewater discharge and runoff have contaminated natural waterways and aquifer recharge basins.A case study from the Tampa Bay,Florida(U.S.)region reveals that water suppliers are providing conservation incentives to consumers as a cost-effective alternative to expanding infrastructure capacity to meet the demands of population and economic growth.Research at the University of Florida shows the benefit-cost of several water saving alternatives and the corresponding“willingness-to-pay”for several consumer markets.Together,a methodology is introduced wherein the water supplier can create“optimal”market-based incentives for consumer investment in water saving measures that maximize water use reductions and minimize conservation program costs.The indirect costs of water use such as energy emissions and watershed destruction(externalities)is also addressed.

Advances in LID BMPs research and practice for urban runoff control in China

China is at present experiencing a very rapid urbanization process, which has brought a number of adverse impacts upon the water environment. In particular, urban runoff quantity and quality control have emerged as one of the key concerns for municipal officials. One of the strategies being considered is the use of a Low Impact Development type of Best Management Practices （LID BMPs） for urban storm water runoff quantity and quality control. In this paper, the situation surrounding urban runoff control in China is reviewed first. Then the conventional strategy and technologies for the construction and management of urban drainage systems are discussed, while exploring their inherent dilemmas. The LID BMPs are then introduced to control urban runoff in the context of urban sustainable water systems. After the comprehensive analysis of the various LID BMPs, the advances in LID BMPs research and practice for urban runoff control in China are investigated and summarized. At last, the difficulties of implementing LID BMPs in China are discussed, and a direction for the future is proposed.

Probability mass first flush evaluation for combined sewer discharges

The Korea government has put in a lot of effort to construct sanitation facilities for controlling non-point source pollution. The first flush phenomenon is a prime example of such pollution. However, to date, several serious problems have arisen in the operation and treatment effectiveness of these facilities due to unsuitable design flow volumes and pollution loads. It is difficult to assess the optimal flow volume and pollution mass when considering both monetary and temporal limitations. The objective of this article was to characterize the discharge of storm runoff pollution from urban catchments in Korea and to estimate the probability of mass first flush （MFFn） using the storm water management model and probability density functions. As a result of the review of gauged storms for the representative using probability density function with rainfall volumes during the last two years, all the gauged storms were found to be valid representative precipitation. Both the observed MFFn and probability MFFn in BE-1 denoted similarly large magnitudes of first flush with roughly 40% of the total pollution mass contained in the first 20% of the runoff. In the case of BE-2, however, there were significant difference between the observed MFFn and probability MFFn.

Flow and mass balance analysis of eco-bio infiltration system

A structued stormwater infiltration system was developed and constructed at a university campus and monitoring of storm events was performed during a one- year operation period. The flow and pollutant mass balances were analyzed and the overall efficiency of the system was assessed. While significant positive correla- tions were observed among rainfall, runoff and discharge volume （R2= 0.93-0.99; p 〈 0.05）, there was no sig- nificant correlations existed between rainfall, runoff, discharge volume and pollutant load. The system was more effective in reducing the runoff volume by more than 50% for small storm events but the difference between the runoff and discharge volume was significant even with rainfall greater than 10ram. Results showed that the pollutant reduction rates were higher compared to the runoff volume reduction. Average pollutant reduction rates were in the range of 72% to 90% with coefficient of variation between 0.10 and 0.46. Comparable with runoff reduction, the system was more effective in reducing the pollutant load for small storm events, in the range of 80% to 100% for rainfall between 0 and 10mm; while 65% to 80% for rainfall between l0 and 20mm. Among the pollutant parameters, particulate matters was highly reduced by the system achieving only a maximum of 25% discharge load even after the entire runoff was completely discharged. The findings have proven the capability of the system as a tool in stormwater manage- ment achieving both flow reduction and water quality improvement.