Groundwater risk assessment at a heavily industrialised catchment and the associated impacts on a peri-urban wetland

Industrial and agricultural activities often impose significant pressures to the groundwater quality and consequently degrade wetland ecosystems that depend mostly on subsurface water flow. Groundwater vulnerability and risk mapping is a widely used approach to assess the natural protection of aquifers and the associated pollution potential from human activities. In the particular study, the relatively new Pan-European methodology (COP method) has been applied in a highly industrialized peri-urban wetland catchment, located close to Athens city, to map the intrinsic vulnerability of the aquifer and evaluate the risk potential originating from local land uses. Groundwater analysis results for various parameters, including Phenols, PCBs and nutrients, have been used to validate the vulnerability and risk estimations while a biological assessment occurred to associate the mapping results with the wetland's ecological status. The results indicated that even though the natural protection of the aquifer is relatively high due to the dominant hydrogeologic and geomorphologic conditions, the groundwater pollution risk is considerable, mainly because of the existing hazardous land uses. The water quality of the groundwater accredited these findings and the ecological status of this peri-urban wetland also indicated significant impacts from industrial effluents.     

A GIS-based DRASTIC vulnerability and net recharge reassessment in an aquifer of a semi-arid region (Metline-Ras Jebel-Raf Raf aquifer, Northern Tunisia)

This paper aims to elaborate new generic DRASTIC aquifer vulnerability maps of the coastal aquifer of Metline-Ras Jebel-Raf Raf (Northeast of Tunisia) using the GIS technique, making the data analyses easier to handle and providing better capabilities of dealing with large spatial data. A similar study was carried out in 1999 in the same aquifer using a method based on the soil water balance equation to determine the net recharge parameter. Unfortunately, the lack of data in the study area made the results unsatisfactory. By applying the Williams and Kissel equation and the Rao relationship, we intend to demonstrate that we could correctly evaluate the net recharge parameter. Moreover, new data related to the aquifer hydraulic conductivity, the soil cover and the vadose zone lithology have become available, and allowed us to elaborate suitable DRASTIC maps.     

Groundwater Vulnerability Assessment Combining the Drastic and Dyna-Clue Model in the Argentine Pampas

Vulnerability assessment is considered an effective tool in establishing monitoring networks required for controlling potential pollution. The aim of this work is to propose a new integrated methodology to assess actual and forecasted groundwater vulnerability by including land-use change impact on groundwater quality. Land-use changes were simulated by applying a spatial dynamics model in a scenario of agricultural expansion. Groundwater vulnerability methodology DRASTIC-P, was modifyed by adding a land-use parameter in order to assess groundwater vulnerability within a future scenario. This new groundwater vulnerability methodology shows the areas where agricultural activities increase the potential level of groundwater vulnerability to pollution. The Dulce Creek Basin was the study case proposed for the application of this methodology. The study revealed that the area with Very High vulnerability would increase 20% by the year 2020 in the Dulce Creek Basin. This result can be explained by analyzing the land-use map simulated by the Dyna-CLUE model for the year 2020, which shows that the areas with increments in crop and pasture coincide with the area defined by the Very High aquifer vulnerability category in the year 2020. Through scenario analysis, land-use change models can help to identify medium or long term critical locations in the face of environmental change.     

Decentralized Groundwater Recharge Systems Using Roofwater and Stormwater Runoff1

Stephens, Daniel B., Mark Miller, Stephanie J. Moore, Todd Umstot, and Deborah J. Salvato, 2011. Decentralized Groundwater Recharge Systems Using Roofwater and Stormwater Runoff. Journal of the American Water Resources Association (JAWRA) 48(1): 134‐144. DOI: 10.1111/j.1752‐1688.2011.00600.x Abstract: Stormwater capture for groundwater recharge in urban areas is usually conducted at the regional level by water agencies. Field and modeling studies in New Mexico indicate that stormwater diverted to retention basins may recharge about 50% of precipitation that falls on the developed area, even in dry climates. Comparable volumes of recharge may be expected at homes, subdivisions, or commercial properties with low‐impact development (LID) technologies for stormwater control that promote recharge over evapotranspiration. Groundwater quality has not been significantly impacted at sites that have been recharging stormwater to aquifers for decades. Distributed recharge systems may be a good alternative to centralized regional facilities where there is limited land for constructing spreading basins or little funding for new infrastructure. LID technologies borrowed from stormwater managers are important tools for groundwater managers to consider to enhance recharge.     

Integrated Use of GLEAMS and GIS to Prevent Groundwater Pollution Caused by Agricultural Disposal of Animal Waste

/ In modern intensive animal farming the disposal of a large amount of waste is of great concern, as, if not properly performed, it can cause the pollution of water, mainly because of the high content of nitrate and phosphate. This paper presents the results of a study intended to assess the environmental sustainability of animal waste disposal on agricultural soils in the alluvial plain of the River Chiana (Tuscany, Italy), a particularly sensitive area because of the high vulnerability of the shallow aquifer and of the intensive agricultural and breeding activities. With this aim, a strategy has been employed, that consists of the integrated use of a management model and GISs. The consequences on groundwater of applying animal waste to different kind of soils and crop arrangements have been simulated by means of the management model GLEAMS (Groundwater Loading Effects of Agricultural Management Systems, ver 2.01). As the huge amount of data required by such a sophisticated model does not allow applications at a scale larger than the field size, IDRISI and GRASS GIS packages have been used to divide the study area into land units, with homogeneous environmental characteristics, and then to generalize on these units the outputs of the model. The main conclusions can be synthesized as follows: The amount of animal waste produced in some of the investigated areas (i.e., municipal territory) is greater than that disposable on their own agricultural soil with no risks to the groundwater; consequently a cooperative approach among municipalities is necessary in order to plan waste disposal in a comprehensive and centralized way.KEY WORDS: Land use; Animal waste disposal; Groundwater protection; GIS, Management models     

Vulnerability and risk evaluation of agricultural nitrogen pollution for Hungary's main aquifer using DRASTIC and GLEAMS models

In recent years, the significant improvement in point source depuration technologies has highlighted problems regarding, in particular, phosphorus and nitrogen pollution of surface and groundwater caused by agricultural non-point (diffuse) sources (NPS). Therefore, there is an urgent need to determine the relationship between agriculture and chemical and ecological water quality.This is a worldwide problem, but it is particularly relevant in countries, such as Hungary, that have recently become members of the European Community. The Italian Foreign Ministry has financed the PECO (Eastern Europe Countries Project) projects, amongst which is the project that led to the present paper, aimed at agricultural sustainability in Hungary, from the point of view of NPS. Specifically, the aim of the present work has been to study nitrates in Hungary's main aquifer. This study compares a model showing aquifer intrinsic vulnerability to pollution (using the DRASTIC parameter method; Aller et al. [Aller, L., Truman, B., Leher, J.H., Petty, R.J., 1986. DRASTIC: A Standardized System for Evaluating Ground Water Pollution Potential Using Hydrogeologic Settings. US NTIS, Springfield, VA.]) with a field-scale model (GLEAMS; Knisel [Knisel, W.G. (Ed.), 1993. GLEAMS—Groudwater Leaching Effects of Agricultural Management Systems, Version 3.10. University of Georgia, Coastal Plain Experimental Station, Tifton, GA.]) developed to evaluate the effects of agricultural management systems within and through the plant root zone. Specifically, GLEAMS calculates nitrate nitrogen lost by runoff, sediment and leachate.Groundwater monitoring probes were constructed for the project to measure: (i) nitrate content in monitored wells; (ii) tritium (³H) hydrogen radioisotope, as a tool to estimate the recharge conditions of the shallow groundwater; (iii) nitrogen isotope ratio δ¹⁵N, since nitrogen of organic and inorganic origin can easily be distinguished.The results obtained are satisfactory, above all regarding the DRASTIC evaluation method, which is shown to satisfactorily explain both low and high aquifer vulnerability, and furthermore proves to be a good tool for zoning hydrogeological regions in terms of natural system susceptibility to pollution. The GLEAMS model, however, proves not to be immediately usable for predictions, above all due to the difficulty in finding sufficient data for the input parameters. It remains a good tool, but only after an accurate validation, for decision support systems, in the specific case to integrate intrinsic vulnerability, from DRASTIC (or similar methods), with land use nitrate loads from GLEAMS, or similar methods.The PECO project has proved a positive experience to highlight the fundamental points of a decision support system, aimed to mitigate the nitrate risk for groundwater coming from Hungarian agricultural areas.     

Assessing ground water vulnerability with the type transfer function model in the San Joaquin Valley, California

The recently developed type transfer function (TTF) simulation approach was applied to generate a regional-scale nonpoint-source ground water vulnerability assessment for the San Joaquin Valley, California. The computationally comparatively inexpensive TTF approach produces quantitative estimates of contaminant concentrations for large regional scales through characteristic functions based on different soil textures and their leaching properties. The TTF simulations employed an extensive soil and recharge database to estimate atrazine (1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine) concentrations at a compliance depth of 3 m resulting from a surface application. Two different sets of TTFs with two different levels of upscaling were used for spatially uniform and distributed recharge estimates. Results show that estimated atrazine concentrations can be related to soil survey information. Areas with high potential vulnerability to atrazine leaching were found for soils with low organic carbon content and sandy loam and loam textures. Travel times for atrazine peak concentrations to the compliance depth ranged from 350 to 730 d. The extent of areas with estimated atrazine concentrations above the maximum contaminant level was less extensive when uniform annual recharge values were used. Simulated TTF concentrations were highest for eastern Fresno County, a vulnerability pattern that is also supported by field observations. The TTF modeling approach is shown to be a useful tool for quantitative pesticide leaching estimates at regional scales significantly larger than those of previous studies.     

UTILIZING INDUCED RECHARGE FOR REGIONAL AQUIFER MANAGEMENT1

ABSTRACT: The deep aquifers of the Portland Basin are used as a regional water supply by at least six municipalities in Oregon and Washington. Maximum continuous use of the aquifers in 1998 was 13 mgd and peak emergency use was 55 mgd. Continuous use of the deep aquifers at a rate of 55 mgd has been proposed and inchoate water rights have been reserved for expansion of pumping to 121 mgd. A study was completed, using a calibrated ground water flow model, to evaluate the role of induced recharge from the Columbia River in mitigating aquifer drawdown from continuous‐use and expanded pumping scenarios in the center and eastern areas of the basin. The absolute average residual was less than 3.6 feet for steady‐state model calibrations, and less than 8.0 feet for transient calibration to a 42 mgd pumping event in 1987 with 170 feet of drawdown. Continuous use of the aquifers at a rate of 55 mgd is predicted to increase drawdown to 210 feet. Expansion of pumping to 121 mgd in the center basin is predicted to cause 400 feet of drawdown. However, expansion of pumping in the east basin is predicted to result in only 220 feet of drawdown because of induced recharge from the Columbia River.     

Sources of water pollution and evolution of water quality in the Wuwei basin of Shiyang river, Northwest China

Based on surveys and chemical analyses, we performed a case study of the surface water and groundwater quality in the Wuwei basin, in order to understand the sources of water pollution and the evolution of water quality in Shiyang river. Concentrations of major chemical elements in the surface water were related to the distance downstream from the source of the river, with surface water in the upstream reaches of good quality, but the river from Wuwei city to the Hongya reservoir was seriously polluted, with a synthetic pollution index of 25. Groundwater quality was generally good in the piedmont with dominant bicarbonate and calcium ions, but salinity was high and nitrate pollution occurs in the northern part of the basin. Mineralization of the groundwater has changed rapidly during the past 20 years. There are 23 wastewater outlets that discharge a total of 22.4 x 10(6)m(3)y(-1) into the river from Wuwei city, which, combined with a reduction of inflow water, were found to be the major causes of water pollution. Development of fisheries in the Hongya reservoir since 2000 has also contributed to the pollution. The consumption of water must be decreased until it reaches the sustainable level permitted by the available resources in the whole basin, and discharge of wastes must also be drastically reduced.     

Agricultural Land Use and Best Management Practices to Control Nonpoint Water Pollution

In recent years, improvements in point-source depuration technologies have highlighted the problems regarding agricultural nonpoint (diffuse) sources, and this issue has become highly relevant from the environmental point of view. The considerable extension of the areas responsible for this kind of pollution, together with the scarcity of funds available to local managers, make minimizing the impacts of nonpoint sources on a whole basin a virtually impossible task. This article presents the results of a study intended to pinpoint those agricultural areas, within a basin, that contribute most to water pollution, so that operations aimed at preventing and/or reducing this kind of pollution can be focused on them. With this aim, an innovative approach is presented that integrates a field-scale management model, a simple regression model, and a geographic information system (GIS). The Lake Vico basin, where recent studies highlighted a considerable increase in the trophic state, mainly caused by phosphorus (P) compounds deriving principally from the intensive cultivation of hazelnut trees in the lake basin, was chosen as the study site. Using the management model Groundwater Loading Effects of Agricultural Management Systems (GLEAMS), the consequences, in terms of sediment yield and phosphorus export, of hazelnut tree cultivation were estimated on different areas of the basin with and without the application of a best management practice (BMP) that consists of growing meadow under the trees. The GLEAMS results were successively extended to basin scale thanks to the application of a purposely designed regression model and of a GIS. The main conclusions can be summarized as follows: The effectiveness of the above-mentioned BMP is always greater for erosion reduction than for particulate P reduction, whatever the slope value considered; moreover, the effectiveness with reference to both particulate P and sediment yield production decreases as the slope increases. The proposed approach, being completely distributed, represents a considerable step ahead compared to the semidistributed or lumped approaches, which are traditionally employed in research into tools to support the decision-making process for land-use planning aimed at water pollution control.     

RECHARGE ESTIMATES USING A GEOMORPHIC/DISTRIBUTED-PARAMETER SIMULATION APPROACH,AMARGOSA RWER BASIN1

ABSTRACT: Average-annual volumes of runoff, evapotranspiration, channel loss, upland (interchannel) recharge, and total recharge were estimated for watersheds of 53 channel sites in the Amargosa River basin above Shoshone, California. Estimates were based on a water-balance approach combining field techniques for determining streamflow with distributed-parameter simulation models to calculate transmission losses of ephemeral streamflow and upland recharge resulting from high-magnitude, low-frequency precipitation events. Application of the water-balance models to the Amargosa River basin, Nevada and California, including part of the Nevada Test Site, suggests that about 20.5 million cubic meters of water recharges the ground-water reservoir above Shoshone annually. About 1.6 percent of precipitation becomes recharge basinwide. About 90 percent of the recharge is by transmission loss in channels, and the remainder occurs when infrequent storms yield sufficient precipitation that soil water percolates beyond the rooting zone and reaches the zone of saturation from interchannel areas. Highest rates of recharge are in headwaters of the Amargosa River and Fortymile Wash; the least recharge occurs in areas of relatively low precipitation in the lowermost Amargosa River watershed.     

An Aquifer Storage and Recovery system with reclaimed wastewater to preserve native groundwater resources in El Paso, Texas

The traditional concept of Aquifer Storage and Recovery (ASR) has been emphasized and extensively applied for water resources conservation in arid and semi-arid regions using groundwater systems as introduced in Pyne's book titled Groundwater Recharge and Wells. This paper extends the ASR concept to an integrated level in which either treated or untreated surface water or reclaimed wastewater is stored in a suitable aquifer through a system of spreading basins, infiltration galleries and recharge wells; and part or all of the stored water is recovered through production wells, dual function recharge wells, or by streams receiving increased discharge from the surrounding recharged aquifer as needed. In this paper, the author uses the El Paso Water Utilities (EPWU) ASR system for injection of reclaimed wastewater into the Hueco Bolson aquifer as an example to address challenges and resolutions faced during the design and operation of an ASR system under a new ASR system definition. This new ASR system concept consists of four subsystems: source water, storage space-aquifer, recharge facilities and recovery facilities. Even though facing challenges, this system has successfully recharged approximately 74.7 million cubic meters (19.7 billion gallons) of reclaimed wastewater into the Hueco Bolson aquifer through 10 recharge wells in the last 18 years. This ASR system has served dual purposes: reuse of reclaimed wastewater to preserve native groundwater, and restoration of groundwater by artificial recharge of reclaimed wastewater into the Hueco Bolson aquifer.     

Water transfers,agriculture, and groundwater management: a dynamic economic analysis

Water transfers from agricultural to urban and environmental uses will likely become increasingly common worldwide. Many agricultural areas rely heavily on underlying groundwater aquifers. Out-of-basin surface water transfers will increase aquifer withdrawals while reducing recharge, thereby altering the evolution of the agricultural production/groundwater aquifer system over time. An empirical analysis is conducted for a representative region in California. Transfers via involuntary surface water cutbacks tilt the extraction schedule and lower water table levels and net benefits over time. The effects are large for the water table but more modest for the other variables. Break-even prices are calculated for voluntary quantity contract transfers at the district level. These prices differ considerably from what might be calculated under a static analysis which ignores water table dynamics. Canal-lining implies that districts may gain in the short-run but lose over time if all the reduction in conveyance losses is transferred outside the district. Water markets imply an evolving quantity of exported flows over time and a reduction in basin net benefits under common property usage. Most aquifers underlying major agricultural regions are currently unregulated. Out-of-basin surface water transfers increase stress on the aquifer and management benefits can increase substantially in percentage terms but overall continue to remain small. Conversely, we find that economically efficient management can mitigate some of the adverse consequences of transfers, but not in many circumstances or by much. Management significantly reduced the water table impacts of cutbacks but not annual net benefit impacts. Neither the break-even prices nor the canal-lining impacts were altered by much. The most significant difference is that regional water users gain from water markets under efficient management.     

Impacts of Residential Development on Humid Subtropical Freshwater Resources: Southwest Florida Experience1

Abstract: The population of Collier and Lee Counties in southwestern Florida has increased 11‐fold from 1960 to 2004 with a concomitant increase in freshwater demand. Water levels and salinity within the water table aquifer over the past two to three decades have generally been stable, with more monitoring wells showing statistically significant temporal increases in water level than decreases. Residential development has had a neutral impact on the water table aquifer because the total annual evapotranspiration of residential communities is comparable to that of native vegetation and less than that of most agricultural land uses. Public water supply systems and private wells also result in net recharge to the water table aquifer with water produced from deeper aquifers. Confined freshwater aquifers have overall trends of decreasing water levels. However, with the exception of the mid‐Hawthorn aquifer, water levels in most areas recover to near background levels each summer wet season. Freshwater resources in humid subtropical areas, such as southwestern Florida, are relatively robust because of the great aquifer recharge potential from the excess of rainfall over ET during the wet season. Proper management can result in sustainable water resources.     

基于流域视角的水环境综合治理规划研究——以江苏省淀山湖为例

以流域为单元进行水资源综合规划和管理是实现水环境改善的重要途径。本文以太湖流域第二大省界湖泊—淀山湖为例,在综合分析流域水环境质量基础上,利用GIS 分析工具划分流域治理片区并制定分区管控策略。根据流域所含骨干河流流向、骨干河流与淀山湖交汇特点、上中下游不同河段及镇域行政边界,将淀山湖流域分为吴淞江流域、千灯浦- 淀山湖流域、昆南湖荡流域、元荡湖荡流域、太浦河流域五大片区138 个子评价单元。通过水环境容量与压力两类空间叠加分析,构建形成污染重点减排区、污染综合治理区、产业绿色化提升区、生态环境保育区等四个类型区域,并提出差异化的产业准入和环境治理措施。本研究不仅为以流域为治理单元的水环境治理规划提供了较为可行的技术体系,而且为太湖流域水环境综合整治思路创新提供了可借鉴的案例。     

Intrinsic vulnerability assessment of Sette Comuni Plateau aquifer (Veneto Region, Italy)

Maps illustrating the different degrees of vulnerability within a given area are integral to environmental protection and management policies. The assessment of the intrinsic vulnerability of karst areas is difficult since the type and stage of karst development and the related underground discharge behavior are difficult to determine and quantify. Geographic Information Systems techniques are applied to the evaluation of the vulnerability of an aquifer in the alpine karst area of the Sette Comuni Plateau, in the Veneto Region of northern Italy. The water resources of the studied aquifer are of particular importance to the local communities. This aquifer must therefore be protected from both inappropriate use as well as possible pollution. The SINTACS and SINTACS P(RO) K(ARST) vulnerability assessment methods have been utilized here to create the vulnerability map. SINTACS P(RO) K(ARST) is an adaptation of the parametric managerial model (SINTACS) to karst hydrostructures. The vulnerability map reveals vast zones (81% of the analyzed areas) with a high degree of vulnerability. The presence of well-developed karst structures in these highly vulnerable areas facilitate water percolation, thereby enhancing the groundwater vulnerability risk. Only 1.5 of the studied aquifer have extremely high-vulnerability levels, however these areas include all of the major springs utilized for human consumption. This vulnerability map of the Sette Comuni Plateau aquifer is an indispensable tool for both the effective management of water resources and as support to environmental planning in the Sette Comuni Plateau area.     

A management strategy to reduce bacterial pollution in shellfish areas: A case study

The problem of bacterial pollution in shellfishing areas is not uncommon in the coastal regions of the United States. Bacterial contamination from man's activities can effectively reduce our natural shellfish resource areas by forcing their closure because of high potential risk of diseases being spread by shellfish harvested in these areas. Tillamook Bay, a relatively small, enclosed drainage basin of nonurban character, presents an excellent study area for observing this problem. The high population density of animals, raised on a relatively small floodplain area, represents one of the major sources of pollution in the bay. This paper summarizes the history of the agencies involved with the problem and presents the current approach to alleviate bacterial pollution in the bay without unduly penalizing other industries in the Tillamook basin. The paper also presents some of the legal aspects of reducing water pollution in shellfish harvesting areas and the jurisdiction of federal agencies in these matters. Finally, recommendations are given to reduce bacterial output by the major source categories in the basin, and criteria for bay closure to shellfish harvest are developed to protect the public from bacterially contaminated shellfish.     

A Cooperative Approach to Reduce Water Pollution Abatement Cost in an Interjurisdictional Lake Basin

A cooperative approach via transfer fee was developed to improve the cost‐effectiveness of water pollution control in interjurisdictional lake basin management in China. Different from the existing literature that studies water quality trading and pollution reduction at micro levels (i.e., focusing on enterprises and firms), this article explores cooperative pollution reduction strategies from a macro level, targeting multiple jurisdictional regions. The merits of this new approach include: (1) improving the cost‐effectiveness of pollution reduction by making use of the cost differentiation in pollution reduction between industries and municipal sewage plants, and between different administrative areas; (2) managing payments for ecosystem services by horizontal transfer payment; and (3) incorporating the concepts of game, cooperation, coordination, and watershed‐based management in implementation. For empirical demonstration, a bilevel optimization model was built and calibrated using the 2005 data of the Lake Tai basin to work out the optimal solutions for cooperative chemical oxygen demand (COD) reduction. Results show that policies based on this new approach can significantly reduce the overall COD abatement costs for the basin as well as the individual jurisdictional regions compared to the current practice.     

AN EXAMINATION OF THE MECHANISMS CONTROLLING GROUNDWATER GRADIENTS IN HYPER-ARID REGIONAL SEDIMENTARY BASINS1

ABSTRACT: Although evidence of modern recharge in the North African and Arabian sedimentary basin aquifers exists, it is difficult to determine the volume of recharge. Also, from the evidence of regional groundwater gradients, the flow within the aquifers seems to be appreciably greater than one would intuitively expect. A hypotehtical model embodying the characteristics of the aquifers has been used to investigate the likely significance of various possible flow mechanisms. It is shown that while dewatering in the unconfined area can possibly contribute to flows for a considerable period of time, the maintenance of water levels in the unconfined zone must be the result of modern recharge. It is also shown that recharge depths of less than 10 mm per annum are sufficient given suitable aquifer parameters. Results for various combinations of aquifer parameters and configurations are given, including layered aquifers and the effects of restricted oufflows. Comparisons are made using a “bench mark” example. The work indicates that there is little point in carrying out conventional hydrological balance studies in hyper-arid areas and that, instead, more emphasis should be placed upon good groundwater hydrographic data and modeling.     

Application of a Multi-Objective Optimization Method to Provide Least Cost Alternatives for NPS Pollution Control

Nonpoint source (NPS) pollutants such as phosphorus, nitrogen, sediment, and pesticides are the foremost sources of water contamination in many of the water bodies in the Midwestern agricultural watersheds. This problem is expected to increase in the future with the increasing demand to provide corn as grain or stover for biofuel production. Best management practices (BMPs) have been proven to effectively reduce the NPS pollutant loads from agricultural areas. However, in a watershed with multiple farms and multiple BMPs feasible for implementation, it becomes a daunting task to choose a right combination of BMPs that provide maximum pollution reduction for least implementation costs. Multi-objective algorithms capable of searching from a large number of solutions are required to meet the given watershed management objectives. Genetic algorithms have been the most popular optimization algorithms for the BMP selection and placement. However, previous BMP optimization models did not study pesticide which is very commonly used in corn areas. Also, with corn stover being projected as a viable alternative for biofuel production there might be unintended consequences of the reduced residue in the corn fields on water quality. Therefore, there is a need to study the impact of different levels of residue management in combination with other BMPs at a watershed scale. In this research the following BMPs were selected for placement in the watershed: (a) residue management, (b) filter strips, (c) parallel terraces, (d) contour farming, and (e) tillage. We present a novel method of combing different NPS pollutants into a single objective function, which, along with the net costs, were used as the two objective functions during optimization. In this study we used BMP tool, a database that contains the pollution reduction and cost information of different BMPs under consideration which provides pollutant loads during optimization. The BMP optimization was performed using a NSGA-II based search method. The model was tested for the selection and placement of BMPs in Wildcat Creek Watershed, a corn dominated watershed located in northcentral Indiana, to reduce nitrogen, phosphorus, sediment, and pesticide losses from the watershed. The Pareto optimal fronts (plotted as spider plots) generated between the optimized objective functions can be used to make management decisions to achieve desired water quality goals with minimum BMP implementation and maintenance cost for the watershed. Also these solutions were geographically mapped to show the locations where various BMPs should be implemented. The solutions with larger pollution reduction consisted of buffer filter strips that lead to larger pollution reduction with greater costs compared to other alternatives.