GROUNDWATER PROTECTION MODEL AT NIAGARA USING GIS TOOLS

Groundwater Protection Model at Niagara Using GIS Tools Master of Engineering, 2006 By Mafruha Ahmed Department of Civil Engineering Ryerson University Groundwater is the safest and most reliable source of available freshwater. Although traditionally groundwater has been assumed to be free from contamination, numerous discoveries in recent years of toxic chemicals in well water have proven this assumption to be false. Groundwater contamination from chemical dump sites tends to attract the greatest public attention, but contamination from other sources such as septic systems, pesticides, and underground storage tanks also can be significant. Intensive agriculture in areas of high soil permeability and high water tables also causes groundwater contamination from the percolation of chemicals and nutrients through the soil profile. Protecting groundwater resources from pollution is therefore essential for its proper management and preventing probable hazards. Groundwater vulnerability assessment is an issue of spatial distribution and therefore typically carried out using geographic information systems (GIS). Even when using a simple qualitative method, the complex processing of spatial information is completed faster using GIS Models are tools to simulate the behavior of physical systems. They can predict the future evolution of the systems, they can be used as interpretative tools in order to study system dynamics and they can give hints for data collection and design of experiments. Models are sometimes used to examine the evolution of generic natural systems, without a specific application to a definite site or population. ArcGlS 9 provides new tools to build protection model to study groundwater contamination issues of various watersheds that performs multiple geoprocessing operations. The study articulates the most vulnerable locations of Niagara for ground water contamination, what geospatial data are needed to support these resource assessment activities, and how GIS tools are required to facilitate the generation of a best optimized model.


INTRODUCTION 1.1 Overview
Groundwater is water that is found underground in the cracks and spaces in soil, sand, and rock.
Groundwater is the safest and most reliable source of available freshwater. Only three percent o f the E arth's freshwater are located in streams, lakes, and reservoirs. The remaining 97 percent o f freshwater is obtained from underground (Environment Canada, 2006). Groundwater plays an important role in the hydrological cycle. Groundwater is essential to the viability o f the environment, health and growth of a country's economy, particularly the agricultural sector and has important economic significance to a range of urban activities. Groundwater is the main source o f drinking water to most of the people in rural areas.
There are two sources o f water supply available to society -surface sources, which include rivers, lakes and reservoirs, and ground sources, which include wells and springs that tap aquifers and other underground sources. Over 8 million Canadians rely on groundwater as their source o f drinking water (Environment Canada, 2006). Nowadays, the assurance of sufficient and safe water is a major concern in Canada and around the world. There is also concern that where certain bacterial or nitrate concentrations exceed drinking water guidelines in surface or groundwater, there m ay be negative health effects. Other sources o f contaminations are, for example, spillage o f fertilizers and pesticides during handling, runoff from the loading and washing o f pesticide sprayers or other application equipment, using chemicals uphill from or within a few hundred feet o f a well. Contamination of groundwater resource may therefore cause severe environmental and health hazards. As the flow of groundwater is very slow and subject to little turbulence, contaminants in groundwater does not dilute easily. Consequently, once the aquifers are contaminated they become very difficult and costly to remedy and in most cases are abandoned.
Protecting groundwater resources from pollution is therefore essential for its proper management and preventing probable hazards.
Most human-caused groundwater contamination results from the interaction o f recharge water with chemicals at or just below the land surface. The concept of utmost importance is that groundwater originates at the Earth's surface, so its quality is determined by land uses and chemical management practices. As water percolates through the soil, it may pick up contaminants and carry them downward to groundwater.
Chemicals may be deliberately placed in or on the soil for a specific reason; for example, pesticides are sprayed to protect crops, and gasoline is stored in underground tanks for later use.
Waste chemicals may be inadvertently spilled or deliberately applied to land for disposal. Soluble chemicals, which readily dissolve in water, move with groundwater as it flows. Insoluble chemicals do not mix fully with groundwater, and their flow patterns depend on their densities relative to water. The rates of movement and degradation of the compounds depend on a variety of chemical, physical, and biological processes.
Niagara watershed covers approximately 2424 sq. km. covering the whole Niagara Region, 21% o f the City of Hamilton and 24% of Haldimand County (Regional Municipality of Niagara, 2003).
The watershed is drained primarily by the Welland River, Twelve Mile Creek, Twenty Mile Creek, and Forty Mile Creek with a number of smaller water courses draining into Lake Ontario and Lake Erie. The NPCA (Niagara Peninsula Conservation Authority) jurisdiction also encompasses 117 km. of Great Lakes shoreline, with 67 km. on Lake Erie and 50 km. on Lake Ontario (Regional Municipality of Niagara, 2003). The watershed also includes many small tributaries draining directly to the Niagara River from the Town of Grand Island, New York, upstream of Niagara Falls. Waters from the Niagara River are withdrawn for hydroelectric power generation in both the U.S. and Canada and returned to the Niagara River below Niagara Falls.
The Niagara River is the outlet for Lake Erie and the rest of the Great Lakes Basin upstream of Lake Ontario. Eighty-three percent (83%) of the water flowing into Lake Ontario enters through the Niagara River and therefore significantly influences Lake Ontario's water quality and fish productivity. The Niagara River is now one of the U.S.-Canadian International Joint Commissions 42 "Areas of Concern" throughout the Great Lakes Basin (Regional Municipality of Niagara, 2003).
Close proximity to Lakes Erie and Ontario impacts rainfall and snow patterns, moderating the climate o f the Region of Niagara allowing for production of a diverse variety of crops. There are 2266 farms and 205,348 acres of farmland within the watershed (Regional Municipality of Niagara, 2003). Important agricultural sectors include dairy, vegetable production, nursery stock, sod, greenhouse horticulture, vineyards, and small fruit production. Resource concerns revolve around water quality as well as erosion and sediment control, particular as it relates to flooding prevention, storm water runoff and resuspension o f contaminated sediments. Most point sources, including industrial discharges, leaking landfills and municipal sewage discharges are reasonably well controlled but non-point sources of pollution particularly agricultural chemicals remain o f concern and nutrient, manure, and pest management are particularly important agricultural conservation practices in this watershed.
The Niagara is recognized as one of the most significant agricultural areas in Canada. The agricultural contamination sources vary and there are numerous in this area. Agricultural inputs such as fertilizer, livestock manure, and pesticides have still caused water contamination when improperly stored, applied or disposed of high concentrations of organic matter, phosphorus and nitrogen in surface water can lead to its eutrophication and deoxygenation, which in turn destroy aquatic habitat and produce taste, odor and aesthetic problems. Through a combination o f climate, soils, geography, and location, the area has developed an agricultural industry and community that is unique in Canada. Its positioning between two o f the largest fresh water lakes in the world gives it a natural advantage for agriculture not only because of the moderating influence o f the lakes, but also the ready availability o f fresh water. Large quantities o f organic compounds are used by agriculture. These man-made organic compounds are of most concern for groundwater contamination too.
The Niagara rely heavily on groundwater as a source o f supply for its drinking water needs, and are fortunate that the quantity o f groundwater available is capable of meeting the current water demand and that the water is of excellent quality. However, potential threats to the quantity and quality o f this resource exist within the area. The basic groundwater functions (recharging, transmitting, assimilating potential contaminants, storing and discharging water) play an essential role in m aintaining the health o f an ecosystem. Better understanding o f these regional groundwater functions is helpful to provide a secure supply of clean water to municipal and communal water systems, as well as to individual groundwater users who do not have access to a municipal supply.
There are currently 7400 wells in this region, among them only 150 wells are used (Regional M unicipality o f Niagara, 2003). Theoretically, there is unused capacity within the regional aquifers as the current use is only 15% o f the recharge at the regional level (Regional Municipality o f Niagara, 2003). The attempts to use groundwater fi-om below the escarpment have often failed due to the high sulfur content of the extracted water. There are 4898 km o f streams in Niagara Regions, averaging 2.02 km of drainage channel per square kilometer (Regional Municipality of Niagara, 2003). The average annual urban and rural storm runoffs are 56 million cubic meters and 27 million cubic meters, respectively (Regional Municipality of Niagara, 2003). Unfortunately most o f the runoff occurs during periods of rain and this runoff from steep-sloped agricultural fields is one likely source of groundwater contamination. Based on these considerations, agricultural fields near streams should be identified and protection measures of groundwater contamination should be applied.
As groundwater is the only source of potable water in this region, assessing the health risks from chemicals and protecting humans are given high priority in governmental decisions. To this end a complex procedure is required that integrates research and technical expertise from various scientific disciplines. The fate of contaminants in the soil and groundwater as affected by a variety o f environmental and anthropogenic processes and factors would certainly be included in the study. The evolution of existing, and the development of new, agricultural practices and other measures of groundwater quality control and management also be considered.
Groundwater recharge is the portion of infiltrating water that will move downward through the unsaturated zone. When infiltration reaches the water table it becomes groundwater recharge.
Recharge replenishes water in aquifers, or is discharged in springs, streams, lakes, or wetlands.
Whether well water is taken from individual wells or large community well fields, the concepts behind its protection remain the same.
Model can predict the future evolution of the systems, it can be used as interpretative tools in order to study system dynamics and they can give hints for data collection and design of experiments.
Models are sometimes used to examine the evolution of generic natural systems, without a specific application to a definite site or population. More generally, models help to unlock latent tendencies in data, test our understanding of system structure and dynamics, and discuss policy issues in ways that expose assumptions and rules of inference. In ArcGIS, a model is a representation of a system of processes that performs operations on GIS datasets. Through the visual model-building interface, proposed analyses are more easily translated into ordered steps.
Models allow data and tools to be linked together in a user-defined sequence that structures automated geoprocessing tasks such as buffering, converting, overlaying or selecting data. By the groundwater protection modeling the steep-sloped agricultural areas in this region can be identified which is susceptible to contaminate the groundwater through precipitation and which is discharged in springs, streams, lakes, or wetlands.

Objectives
The Niagara watershed characterized by caves, sinkholes, rapid groundwater flow, and many surface streams which are vulnerable to contamination, and groundwater quality in these areas are often closely related to land use practices. The runoff from the steep-sloped agricultural lands is discharged to nearby streams which ultimately discharge to Lake Erie and Lake Ontario. These Areas defined through the model are most vulnerable to contamination of groundwater as the run off infiltrates through different soils and possibly recharge an aquifer or contributes water to a pathway delivering water to an aquifer.

A Few Definitions
Recharge -W ater percolates through the soil to become groundwater in a process called recharge.
The amount o f water recharged in any particular location depends on a number o f factors, including climate, land use, topography, and geological conditions.
Groundwater -Groundwater moves through the ground, below the place where it first enters the soil to the area where it later resurfaces. Flow rates typically are measured in inches or feet per day, although they can be much faster in coarse gravel or in bedrock with large openings or crevices. Groundwater tends to move in parallel paths, with little vertical mixing between layers.
Geological formations that yield significant amounts of groundwater are called aquifers. Contamination -The definition of contamination is defined as the presence of foreign materials, chemicals or radioactive substances in the environment (soil, sediment, water or air) in significant concentrations. Introduction into water, air, and soil of microorganisms, chemicals, toxic substances, wastes, or wastewater in a concentration that makes the medium unfit for its next intended use. Also applies to surfaces of objects, buildings, and various household and agricultural use products.

Aquifers
Watershed -Watershed defines any area lying within the drainage basin of any reservoir.
Karsts -An area of irregular limestone in which erosion has produced fissures, sinkholes, underground streams, and caverns.
Cone of depression -Groundwater movement is affected by the pumping of wells. When water is withdrawn from a well, the water table around the well is lowered, and groundwater from surrounding areas flows toward the well to compensate. The lowered water table around a well is called the cone of depression. The size and shape of the cone of depression depend on many factors, including the rate and duration of pumping, the rate of groundwater recharge, and the geology of the aquifer.
Zone of influence -The area at the land surface lying directly over the cone of depression is called the zone of influence. Although the zone of influence indicates the area in which the water components) o f a particular environment (e.g., estuaries).
Vulnerability -Vulnerability is a term used to represent the intrinsic geological and hydrogeological characteristics that determine the ease with which groundwater m ay be contaminated by human activities.

Structure of report
This report consists of five chapters including an introduction and conclusion. Following the introduction the second chapter provides a brief description about the groundwater contamination and causes, and discusses all the issues o f ground water protection strategy that have been taken into account to avoid or minimize impacts. Third chapter narrows down to GIS applications o f Groundwater, GIS data types, and some GIS initiatives and application at Niagara Region. Fourth chapter presents datasets and the methodology used to develop groundwater protection model using GIS tools at Niagara. Finally, concluding remarks are presented in the fifth chapter. Introduction Pure water is tasteless and odorless. A molecule of water contains only hydrogen and oxygen atoms. Water is never found in a pure state in nature. Both groundwater and surface water may contain many constituents, including microorganisms, gases, inorganic, and organic materials.
Scientists assess water quality by measuring the amounts of the various constituents contained in the water. There are many different types of potential threats to groundwater quality, which may include organic chemicals, hydrocarbons (e.g., benzene in gasoline and TCE in solvents), inorganic cations (e.g., iron and manganese), inorganic anions (chloride and nitrate), pathogens (bacteria and viruses), and radio nuclides (radon and strontium) (Fetter, 1999).
Any addition of undesirable substances to groundwater caused by human activities is considered Contamination problems are increasing in Canada primarily because of the large and growing number of toxic compounds used in industry and agriculture. In rural Canada, scientists suspect that many household wells are contaminated by substances from such common sources as septic systems, underground tanks, used motor oil, road salt, fertilizer, pesticides, and livestock wastes.
Scientists also predict that in the next few decades more contaminated aquifers will be discovered, new contaminants will be identified, and more contaminated groundwater will be discharged into wetlands, streams and lakes.
'T he Ontario Drinking Water" standards were designed to protect public health through the provision o f safe drinking water (MCE, 2001). Water intended for domestic use should not contain disease-causing organisms, or unsafe concentrations of toxic chemicals or radioactive substances. W ater should be aesthetically acceptable, and parameters such as taste, odor, turbidity, and color should be controlled. Drinking water quality criteria must take into consideration several factors that m ay impact the quality o f drinking water, public health, and technology available to treat the water. Both 'standards' and 'objectives' are outlined in the 'Ontario Drinking Water Standards'. If a parameter is assigned a 'standard' there is a maximum acceptable concentration (MAC) assigned to the parameter. The MAC is a health-related standard established for parameters which, when present above a certain concentration, are known or suspected to cause adverse health effects. In

Causes of Pollution
The pollution o f water with chemical contaminants has become one o f the most crutial environmental problems within the 20th century. Pollution is also caused when silt and other suspended solids, such as soil, washoff plowed fields, construction and logging sites, urban areas, and eroded river banks when it rains. Figure   (Source: [David, K., 2000, Water Pollution and Society])

The Hydrologie Cycle
The movement and recycling of water between the atmospheres, land surface, and underground is called the hydrologie cycle. Understanding the hydrologie cycle, and in turn the flux o f water moving into and out of a study area, is critical in properly managing water resources. The hydrologie cycle consists of four main components; precipitation, évapotranspiration, surface water resources, and groundwater resources.
Water on the ground surface, in streams or in lakes can return to the atmosphere through evaporation. Water used by plants can be returned to the atmosphere through transpiration (see  • Ensure that the data is properly managed, ,

Groundwater Protection Strategy
• Use public education to foster groundwater protection, ' " • Acknowledge and protect Wellhead Protection Areas, • Acknowledge and protect areas of medium and high vulnerability, • Monitor groundwater quality, and • Encourage the use of Best Management Practices.
Resource endeavors geared towards providing a safe and secure water source for the Region.
Discussion related to the multi-barrier approach to water protection is included to provide this link. The multi-barrier approach is an integrated system of procedures, processes and tools that collectively prevent or reduce the contamination of drinking water from source to tap, in order to reduce risks to public health (Canadian Council o f Ministers of the Environment, 2002). Figure 3 illustrates the multi-barrier approach schematically, highlighting three key processes o f source protection, treatment, and distribution.
Public in v o lv e m e n t a n d a w a r e n e s s g> / S o u r c e ■g I w a te r x i /p r o te c tio n C le an , s a f e , relia b le d rin k in g . w a te r , D rinking w a te r tr e a tm e n t Legislative and policy frameworks Guidelines, standards and objectives D rinking w a te r d is trib u tio n s y s te m R e s e a r c h , s c i e n c e a n d te c h n o lo g y Figure 3 A multi-barrier approaches to water protection.
(Source: [CCME, 2002]) Source protection is the first of five barriers commonly applied to provide safe drinking water (O'Connor, 2002). The other four barriers include treatment, a secure distribution system, water quality monitoring, and well-plarmed responses to adverse conditions. These potential impacts of agricultural activities on the natural environmental include contamination from excessive nutrients, pathogens, sediment, pesticides, and organic materials. These contaminants could potentially affect the color, smell and taste o f water, and can be represented by four distinct components: • Extent o f agriculture within an area, which is represented by the fraction o f agricultural land within the total area.
• Nature o f agricultural activity -There are two major interrelated biological systems involved in agricultural production activities: those related to crop production and those related to livestock production.
• Intensity o f the agricultural activities as indicated by the levels of management (livestock type and quantity, tillage, nutrient amendments, and pesticides) compared to levels normally used in agricultural enterprises.

• Proximity is an indication o f the connection pathway between agricultural activities and
the component o f the agro-ecosystem resource under consideration. For example, crop production on tile drained land or adjacent to streams or drainage ditches is more likely to result in contamination o f surface water than on land that is farther from surface drainage.
Utilizing best management practices (BMPs) can greatly reduce the risk that different actions have on groundwater resources. Providing information about BMPs in sensitive areas such as WHPAs (wellhead protection areas) can help to protect groundwater resources.
Land Acquisition Acquiring land in a highly sensitive area should provide complete control over the land use practices within the area. In many cases this option is not feasible due to costs and other factors. Land can be acquired prior to the development of a new water supply, or future water supplies can be developed in areas where land is owned by the municipality.

Conservation Easements A conservation easement is a voluntary agreement between a
landowner and a conservation body to "conserve, maintain, restore or enhance" the natural ownership. This tool has been available since 1995, when the Conservation Lands Act was revised to allow private landowners to enter into conservation easement with charitable conservation organization, municipal councils, native bands, and conservation authorities. Prior to this, landowners could only enter into conservation easements with the Crown and its agencies.
Incentive Programs Incentive programs can be used to encourage specific actions throughout the Region or within specific sensitive areas such as WHPAs. A variety of incentive programs currently exist, such as those administered by the Ontario Ministry of Agriculture and Food (Healthy Futures). Additional incentives, focused in higher risk areas, can be used to properly decommission abandoned boreholes, upgrade existing chemical storage, properly maintain septic systems, compensate for loss of land use or productivity, and provide hazardous waste disposal.

Municipal Site Leadership
By adopting an active role and implementing BMPs at municipal sites, the Region and their member municipalities will have much more credibility when asking other land users to adopt similar policies. In many instances, public lands reside in the most sensitive areas from WHPA perspectives. An audit of each well house and the area around the well, and the subsequent removal of potential contaminant sources such as fertilizers, lawn chemicals, paints, oils, fuels, and other contaminants can be completed.

Integrated Information Management An information management system is essential to
incorporate all available information during decision-making. A relational database linked to a GIS can bring together water quality, WHPAs, groundwater vulnerability, land uses, potential and known contaminant sources. Infonnation can also be implemented in a web application for distribution to county residents.

Water Quality Monitoring
The development of "sentinel wells" to provide water quality monitoring that could detect adverse water quality conditions up gradient of the production wells provides a warning system of potential well contamination. Sentinel wells are typically located a distance, in groundwater time-of-travel, of 2 to 5 years up gradient of the production well to provide opportunity to investigate and mitigate water quality concerns. Threshold levels, with associated action plans are important facets of this groundwater management tool.

Municipal Sewer By-Law
A sewer by-law provides a means to control the substances that are discharged to the sewer. Sewers can leak and be a source of contamination to groundwater.
Furthermore, as part of the by-law, inspections could be carried out to help ensure suitable chemical storage. An inventory o f chemical storage provides additional information that can be used to promote BMPs.

Groundwater Protection Strategy Approach
A comprehensive approach to water resource management is needed to address the myriad water quality problems that exist today from non-point and point sources as well as from habitat degradation. The groundwater protection strategy approach is a management approach for more effectively protecting and restoring aquatic ecosystems and protecting human health. actions and practices of people on a day-by-day basis that will help protect water resources (i.e., proper use, storage and disposal of fuels, solvents, and pesticides, regular water well maintenance, installation of water saving plumbing fixtures). Municipalities can work towards developing a "water ethic" in their communities. This means instilling a collective awareness, responsibility, and commitment to protect water on an ongoing basis.
The approach to developing a protection strategy is based on a number of assumptions: • Water is the single most important resource for a healthy community and, as a result, a preventative or proactive approach is more appropriate than a reactive approach (i.e., prevent contamination as opposed to cleaning it up), • Water is not confined by political boundaries, • While the focus is on groundwater protection, the linkage to surface water resources (i.e., water cycle) necessitates a broad-based approach, • Existing risks can be reduced through redevelopment or relocation of land uses that may threaten water quality, • Water quantity (well yields) will remain eonstant, • Impacts can be monitored through development decisions and the collection o f data and that the strategy will be adjusted, where necessary, and • A source protection strategy is a risk management tool that will not provide an absolute solution, but rather, will minimize potential negative impacts over the short and long tenn. The

Groundwater at the Region of Niagara
The Niagara Region is located in the southern part o f Ontario (Canada) between Lake Ontario and Lake Erie. Given the presence o f Niagara Falls, the Niagara Region is home to one o f the most renowned stretches of water; the Niagara River. The existing irrigation practice in this region depends on the existing inigation infrastructures and existing water sources.
Most farmers in the Niagara-on-the-Lake (NOTL) irrigate. The iiTigation is also widely practiced in St. Catherine too. The source of irrigation water in NOTL is generally the municipal drain systems (Niagara-on-the-Lake-Irrigation Systems); however, a few larger operations near Lake Ontario and the Niagara River use these surface water bodies as their sources. For other irrigation infrastructures, on-farm irrigation infrastructures used currently is also significant. W here accessible water sources exist, many farmers have on-farm capacity for applying sufficient amounts o f water to most o f their land. There is also substantial on-farm storage in these areas. Some of the irrigators in these areas have on-farm ponds for irrigation. A few farmers have raw water supply systems for irrigation, generally supplied by Lake Ontario or Niagara River and some times from drilled wells. The Welland canal (shown in Figure 3) that was constructed between Lake Erie and Lake Ontario is also as one of the sources of NOTL irrigation systems.
The existing natural water sources for irrigation are Lake Erie, Lake Ontario, Niagara River, surface streams and run-off (which is stored during rainy season), and groundwater. Lake Erie marks the southern border of the Niagara Region. Its water flows through and by the Region via a number of natural and man-made waterways. Niagara River is the western boundary (see Figure   4). The waters in downstream of the river have the advantage of being close to NOTL and supplied water for irrigation. Lake Ontario makes the northern boundary, which is relatively close to majority of the agricultural lands. The major advantage of this source is the seemingly Irrigation is generally practiced in from early July to mid-September. Most farmers have invested their substantial capital on irrigation systems. However, even those who practice irrigation have some sites that are not irrigated due to source limitations or unfeasibility o f irrigation. Even at sites that have irrigation, most farmers cannot get the option o f connecting to a regional water supply system. Therefore a large part of farmers to meet their requirements use gi'oundwater.
Groundwater is a significant source o f rural, residential, and agricultural water supply within the jurisdictional area o f the Niagara. Groundwater sustains most rivers, lakes, and wetlands in this region, especially during times o f drought. The increasing demand for groundwater supplies to support crop irrigation, aggregate extraction, and urban development are potentially creating additional stresses on the availability of groundwater supplies at Niagara. Unfortunately theoretically, there is unused capacity within the regional aquifers as the cunent use is only 15% o f the recharge at the regional level (Regional Municipality of Niagara, 2003). Therefore a variety o f potential groundwater contamination risks have been identified, including, improperly constructed and/or abandoned water wells, fertilizers, pesticides, septic systems, road salt, landfill sites, and historic oil exploration. The land cover and land use in the Region o f Niagara are shown in Table 1.  Table 2 and Table 3.

Previous Studies
Numerous reports related to groundwater resources investigation and conservation in the Niagara has been published over the past few years. These reports include local-scale hydro geologic analyses, as well as regional-scale assessments of groundwater resources within the region. They provide a useful source of information on the geology and hydrogeology of the region.
As part o f developing a water and wastewater servicing strategy for the Township o f Waintleet. a Groundwater Impact Assessment was completed for the Regional Municipality o f Niagara (MacViro, 2002). This study identified and assessed the potential impacts o f the existing private w ater and sewage systems on the health and safety of the public and the environment along the Lake Erie shoreline near the Onondaga Escapement. Due to the presenee o f fractured bedrock and areas o f thin soil cover, the study concluded that mueh of the study area would be defined as hydrogeologically sensitive. The report indicated that MOE would not normally support development on individual services in these locations (MacViro, 2002 andMOE, 1996). Local groundwater resources as a result were considered at high risk of contamination from bacteria, nitrate, and other sewage effluent contaminants.
A study was completed for the Niagara-Welland are to assess gioundwater resources in the N iagara area to provide a framework for future studies and to quantity the impact o f toxic chemical loading to the Niagara River (Lee, 1987). The study looked in detail at the geology and hydrogeology o f the Niagara area as well as the Welland River drainage basin, and found that the m ost signifleant water resource problems exist in isolated areas related to dewatering, irrigation, and flooding. The study also reported that the poor groundwater quality in the area is related to slow groundwater movement through the overburden, which pennits significant chemical dissolution o f naturally occurring chemical parameters. Groundwater quality problems from contaminant sources were found to have localized impacts. The total recharge to the bedrock aquifer was estimated for the study area to be the equivalent of 4 m^/sec, and the groundwater takings were estimated to be equivalent to 0.3 m^/sec, leading the authors to conclude that there appears to be sufficient groundwater in the area to support continued development. Feenstra (1981) completed a report examining the surficial quaternary geology as well as the bedrock geology and industrial mineral potential of the Niagara-Welland area. This report provides excellent discussion on the origin of the landforms and surficial features o f the area. The report also includes discussion on the aggregate (bedrock and overburden) potential in the study area.

Experiences in Other Jurisdictions
Source protection is not new in Ontario or other jurisdictions across North America. Groundwater protection programs are becoming more common in communities across North America due to the increased impetus to provide and protect clean drinking water. Many municipalities that rely on groundwater are taking proactive measures to safeguard the quality of their water from past, present, and future land uses. In Zones B and C, groundwater may be extracted from the aquifer (quantity limited) by wells that are not municipal wells. Restrictions are relaxed on uses prohibited in Zone A, when they are located in Zones B and C (i.e., liquid manure may be stored, but in a clay lined pit; livestock may be grazed if fenced; limited quantities of petroleum products may be stored; pesticide use is permitted to manufacturer's specifications).

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In Zone C larger quantities o f chemicals may be stored, and fertilizers m ay be applied. New residential, commercial, and industrial buildings may be constructed if communally serviced or where the number of residents and employees serviced by septic tanks does not exceed 25/ha.
Drainage patterns for wetland areas cannot be modified without conducting an impact study on the hydrology and hydrogeology. The province has parallel restrictions to protect sensitive aquifer areas o f interest is a maximum floor area size limit of 185 m" for a single detached dwelling and a prohibition against any conversion of a single to a multiple unit in the highest sensitivity area. In this area, fertilizer application is limited to inorganic applications.

Regional M unicipality of Waterloo (Ontario)
The Measures applied as part of a groundwater protection strategy vary across different regions of Canada and the US. Typically, the approach that is adopted depends on local hydrologie and hydrogeologic conditions, soil structure, land use activities, legislative experience, and the importance of water in the publie policy agenda.
The most successful approaches depend on a package of protection measures that are both voluntary and regulatory. This is essential since much of the landscape has been developed and municipalities have limited authority to implement retroactive land use controls. Also, the resources may not exist to expropriate or acquire lands or buildings that constitute a potential or actual threat to contamination or which could serve as a buffer area (for instance, in the highest sensitivity area of a WHPA). The development of a Groundwater Protection Strategy should consist of measures which provide an affordable and reasonable level of protection, and which can be adapted to changing circumstances.

.1 In tr o d u c tio n
Geographic information system (GIS) is one o f the most important tools for integrating and analyzing spatial information from different sources or disciplines. It helps to integrate, analyze, and represent spatial information and database o f any resource, which could be easily used for planning o f resource development, environmental protection and scientific researches, and investigations.
M any computerized tools have been used for the groundwater assessment, development and overall management in the world. Geographic information systems have emerged in the last decade as an essential tool for urban and resource planning and management. GIS is a userfriendly decision support tool for the monitoring and management of spatially distributed groundwater. The need for integration of information and data is critically important to know the groundwater potential and thereby to design sustainable development strategies which would enable to utilize the resource without affecting the environment.
GIS is a powerful tool for environmental and water resources data analysis and planning. W ater resources assessment of a region involves a detailed study o f the surface and sub-surface water. To integrate the entire surface and sub-surface data manually requires huge manpower and time. By adopting a GIS platform the result obtained will be faster and more accurate. Their capacity to store, retrieve, analyses, model, and map large areas with huge volumes of spatial data has led to an extraordinary proliferation o f applications. GIS stores spatial information and data, which can be overlaid with data or other layers o f information into a map in order to view spatial information and relationships. Figure 5 shows an example of watershed data overlays. The GIS assisted database system would help to apply groundwater management practices such as proper groundwater resource management in terms of groundwater quality and quantity, integrated management of water, land use and the environment, to optimize pumping rates with respect to the capacity of the aquifer system, and to prevent groundwater quality deterioration through proper monitoring and evaluation.
The GIS has two goals in terms of groundwater management: • Spatial analysis of phenomena and processes within a watershed; and • The management of land resources and ecosystems.
GIS provides the opportunity for efficient and improved processing and analysis of geographical information. Spatially varied information are, such as precipitation, evaporation, land use, soil properties, and soil moisture contents, etc. Environmental data are needed for one or more o f the following reasons (Harmancioglu et al., 1998;Varma, 1996): 1. To identify the nature, trends, and anomalies in characteristics of environmental processes in order to better understand these processes. 6. To conduct environmental impact assessment.
7. To monitor and assess the general quality of the environment at regional to global scales.
8. To develop, calibrate, and validate models of environmental processes.

G IS D ata
D ata is the core o f any GIS. The most important and often the most expensive part o f an effective GIS on any application is data that is specially coded to include infonnation about location. The availability o f appropriate and adequate environmental data, and the full extraction o f information fi'om collected data, is important concerns. These data generally come in different format and from various sources and measurements. Spatio-temporal data are collected primarily by means o f field surveying, instrumentation, photogrammetry, and remote sensing. Field data collection using sampling, surveying, and GPS instruments may be required for gathering geospatial information.
The examination and organization of data into a useful form produces information, which then enables appropriate analysis and modeling.
Two important concepts that apply to data quality are precision and accuracy. Data precision refers to the number o f decimal places used to represent measurements o f such things as geographic coordinates, chemical concentrations in giound water, metrological observations, etc.
Accuracy is a measure of how closely data represents reality within specified tolerances. The appropriate level o f data precision and accuracy will depend on the data type o f application and analysis for which the data are being used.
3.2.1 G IS D ata Types Data used for GIS analysis mainly spatial data, attribute data, temporal data and metadata. Spatial data contains the location and shape of geographic features such as roads, land parcels, vegetation stands on the earth surface etc, which may be discrete or continuous. Discrete features are individually distinguishable features that do not exist between observations. Discrete features include points (e.g., wells), lines (e.g., roads), and areas (e.g., land-use types). Continuous features are features that exist spatially between observations.  Attribute (tabular) data describe the characteristics o f spatial features. For raster data, each cell has a value that corresponds to the attnbute of the spatial feature at that location. For vector data, the amount o f attribute data to be associated with a spatial feature can vary significantly.
Temporal data generally exhibit variation and change over time. For example temperature, wind speed and direction, and precipitation as recorded by weather stations. Metadata are information about data, and as such, are most useful when data are transfened between users. Typieal metadata might inelude such things as map projections, source materials and date aequired, and how the data was processed. The absence o f metadata severely limits the utility o f any spatial data.

G IS D ata F orm ats
The term file fonnat refers to the logical structure used to store information in a GIS file. File formats are important in part because not every GIS software package supports all formats. If it is required to use a data set, but it isn't available in a format that GIS supports, then it have to find a way to transform it, find another data set, or find another GIS.
Alm ost every GIS has its own internal file format. These formats are designed for optimal use inside the software and are often proprietary. They are not designed for use outside their native systems. M ost systems also support transfer file formats. Transfer formats are designed to bring data in and out o f the GIS software, so they are usually standardized and well documented.
AreGIS can read a variety of file formats. Many of these are eome from older versions o f the software. Some o f these file formats is described below: S hape files Shape files are vector data files developed for the early version o f Arc View and have been carried over into ArcGlS. They do not store topology and they can contain only one feature class .They m ay contain points, lines, or polygons, and their attributes data are stored as dBase files (extension.dbf). A shape file is actually a collection of files on the disk, with a common name but different extensions (e.g., road.shp, roads.dbf, roads.shx) Coverage It is the vector data format developed for Arc/Info, and the oldest o f the data formats.
They are topological data sets and usually contain multiple feature classes. Coverages are also composed o f multiple files on the disk and even spread data among multiple folders.
Geodatabase It is the newest spatial data format. They can contain multiple feature classes, including tables not linked with spatial data. They are stored as a single database files, and require an underlying database system to operate. They can store topological relationships between feature and feature classes. Two types of geodatabases are used by ArcGlS such as personal geodatabases and multiuser geodatabases. Personal geodatabases are based on Microsoft Access database technology.
Layer It does not contain spatial data. Instead they reference a spatial data file and store information on how it is to be displayed. Layers can be created to store a set of symbols for displaying a particular datasets, and can be used over and over. Several layers can be combined to form a group layer.
Image This data ranges from satellite images and aerial photographs to scanned maps (maps that have been converted from printed to digital format). Image data offers a quick way to get spatial data for a large area and is more cost and time-effective than trying to collect layers o f data like buildings, roads, lakes etc, one at a time. Image data is the best choice if it is need to add a point of reference to vector data without attaching additional information.

DEM (Digital Elevation Model)
It is a raster format used by the USGS to record elevation information. Unlike other raster file formats, DEM cells do not represent color brightness values, but rather the elevations of points on the earth's surface.
CAD drawings Data sets created by CAD programs can be read by ArcGlS, although they cannot be edited or analyzed unless they are converted to shape files or geodatabases. A CAD file may contain multiple feature classes, which correspond to the layers of the drawings, and can be opened separately and viewed Just like feature classes in a coverage or a geodatabase. One can also access CAD drawings, which portray all the features in the CAD file with preset symbols.
T IN s Triangulated Irregular Networks that store surface information, such as elevation, using a set o f nodes and triangles.

Internet Servers
Many organizations now make data available over the Internet. Data Committee (FGDC) has established the National Geospatial Data clearinghouse, as well as standards for the minimum set o f metadata necessary to adequately describe geospatial data, thereby facilitating its use by others. Invariably these data have to be processed and manipulated to m ake them amenable for use in modeling and analysis. Digital data is created by the process o f converting existing maps or graphic documents into an appropriate digital form using digitizing or scanning methods. Map conversion projects need to pay attention to scale, level of generalization, datum, coordinate system, projection, data o f source, and accuracy (Fisher, 1991). One of the strengths of GIS is the ability to integrate data from diverse sources. An environmental application or modeling effort may require the use of traditional maps containing point, line, and polygon features, as well as grids, satellite images, digital elevation models (DEM), digital orthophotos, and scanned data files. Integrating images (raster data) with feature coverages (vector data) has become increasingly common thanks to improvements in GIS data handling capability. Integrating data from diverse sources requires that attention be given to format, scale, projection, coordinate reference system, resolution, precision, and accuracy. Incompatibility may propagate error in GIS and environmental modeling applications (Carlotto, 1995;Heuvelink, 1990).

GIS Modeling Tools
The most successful applications of GIS can be identified in four areas: 1. Mapping; 2. Data pre-processing; 3. Modeling; and 4. Policy formulation.
Hydrologie modeling is the use of physical or mathematical techniques to simulate the hydrologie cycle and its effects on a watershed. The ongoing development of GIS techniques integrated with hydrologie models provides powerful ways to allow us to understand, to visualize, and to analyze hydrologie processes (Singh and Fiorento, 1996). Hydrologie models that have a spatial component can benefit greatly from the use of GIS. Artificial divisions of watersheds into surface water hydrology, vadose zone hydrology, and groundwater hydrology will be abandoned in the future as more research is undertaken.
In recent years various hydrological modeling options have become available in commercial GIS packages. Additionally some hydrological packages have a live link with GIS packages and to perform specific hydrological operations. Comprehensive GIS packages are becoming available that are capable of managing and processing massive quantities of data, and will, therefore, In ArcGIS 9 the model builder interface provides a graphical modeling framework for designing and implementing geoprocessing models that can include tools, scripts, and data. Models are data flow diagrams that link together a series o f tools and data to create advanced procedures and work flows. These tools perform multiple geoprocessing operations to study groundwater contaminations issues of a watershed before reaches to aquifer. Model builder is a productive m echanism to share methods and procedures with others within, as well as outside, any organization. Arc Toolbox and Model builder, available in all ArcGIS Desktop environments, are used for geoprocessing and spatial analysis such as suitability modeling.

GIS Initiatives and Applications at Niagara
The NPCA relies heavily on spatial data, the bulk of which is topographic, environmental or natural resources based land information, to support or directly carry out most o f its day to day tasks. GIS technology has been deployed throughout the NPCA over an ever increasing broad base o f applications and many key Authority programs now depend on its support for efficient data management, mapping, and powerful analytic capabilities. As a result the NPCA continues to integrate the Geographic Information Systems by developing data and applications that serve its business need in order to make informed management decisions. In effect, the Authority has been implementing GIS and geomatics technologies to support its programs with spatial information, improving the efficiencies of day to day operations with digital mapping products and spatial information, improving the efficiencies of day to day operations with digital mapping products and spatial analyses since 2001.
The NPCA GIS program strives to provide high quality, local scale environmental and natural resources geographic data of its jurisdiction to its own programs and its partners in (from catchments of any desirable size and tesselation depending on the management need, to sub watersheds, watersheds and basins) with the ArcHydro tools and data model. This data will serve as the framework from which the Authority's corporate GIS will be based. Water related databases such as municipal drain classification and fish habitat type etc. will build onto and spatially reference the data structure. This development will provide the NPCA with an updated inventory of watercourses and water bodies and a scale more suitable for its management needs, ensuring quality data and mapping for its water resource responsibilities and applications. With the advent of additional datasets as a result of a current and regional groundwater study and aquifer characterization, the NPCA will have a digital and spatial Hydrologie Information System that will account for the entire hydrologie cycle (see Figure 10).

Restoration Applications
The NPCA continues to use GIS to develop mapping products and analyses that support the stewardship based efforts of its Restoration Program. Specifically GIS has assisted staff in assessing the status (statistics) of various natural areas and habitat types on a sub watershed basis, helped develop a spatial database to document, map and tally completed projects to monitor and report restoration success, and to target restoration opportunities with suitability mapping products that ensure the most efficient use o f grant dollars so that projects are implemented where the highest environmental benefits and gains will be experienced.
The NPCA currently implements ESRl's ArcGIS desktop GIS software. Specifically, the Authority maintains a small collection o f ArcView licenses supplemented by an Arc Info, Spatial and 3D Analyst licenses. As an industry leader in GIS technology, ESRI products help the Authority remain highly compatible with its federal, provincial, municipal, and other non government organizations counterparts in conservation. ESRI software is also a natural choice for the Authority as a water management agency since ArcGIS is widely used in the forefront o f research that is developing standard geographic data models and associated tools to extract and relationally store spatial inputs from GIS data for hydrologie and hydraulic numerical models, groundwater protection model, and other water resources applications.

Study Area
The Regional Municipality of Niagara is an area covering 12 unique and distinct local municipalities located in southern Ontario in Canada (RMN, 2006). The Niagara region is a very diverse municipality and covers 1896 sq. km (715 sq. miles) (The Regional Municipality of Niagara, 2006). The municipalities are varying from the larger populated cities of St. Catharines and Niagara Falls with their urban intensive features, to Wainfleet and West Lincoln with a more rural or natural area setting. The total population within the area of jurisdiction is estimated as 460,000.
In this project the study area includes Niagara-on-the-Lake, Niagara Falls, Welland, Thorold, Fort Erie, and St. Catharines (see Figure 11 for a map of the study area). The watershed is drained primarily by the Welland River, Twelve Mile Creek, Twenty Mile Creek and Forty Mile Creek, with a number of smaller watercourses draining into Lake Ontario and Lake Erie.

Data and Data Sources
A proper study and investigations rely on site-specific data and analysis. In order to build a groundwater protection model of the study area the following data is necessary: • Base map; • Land use data ; • Slopes; and • Stream data.
Municipality's data, land use polygon shape data, and stream polygon shape data are shown in  The slope data will be created from digital elevation model (DEM) datasets of the proposed study area. The DEM data is found from GeoBase. GeoBase is a federal, provincial, and territorial government initiative that is overseen by the Canadian Council on Geomatics (CCOG). It is undertaken to ensure the provision of, and access to, a common, up-to-date and maintained base of quality geospatial data for all of Canada.

Data Preparation
Before going through the Model Builder window for building the model, the dataset should be prepared according to the model requirements. In this project to build the groundwater protection ! I model all necessary dataset should be stored into a personal geodatabase feature class in Arc catalog. To do so all dataset should be in the same scale and same format.
Elevation o f the study area in raster data format is obtained from DEM data (shown in Figure 12) and then get slope raster data using spatial analyst extension. The scale o f this DEM data match with the other polygon shape data those are shown in Table 4. Then classified this slope raster data and converted into slope polygon data. Using hydrology tools of Arc GIS 9, watershed data is found. After that all dataset are obtained as same fonnat i.e., vector data format.
% Figure 12 Elevation data of the study area As the scale o f all the dataset are same and at large scales as 1:50,000, so, it isn't needed to convert the scale. Then all the vector datasets are imported in personal geodatabase feature class in ArcCatalog to build the model through the model builder window. Figure 13 shows the personal geodatabase feature class in Arc catalog named Niagara.mdb.  When all geoprocessing operations and SQL expression are ascribed of a model, the model is ready to run. The process model is shown in Figure 15. The default elements colours are blue for project data, yellow for tools, and green for derived data elements. When the model is run, the tool element for each active process turn red and status messages are appeared on the screen.  Figure 15 The process model Through the visual model-building interface, proposed analyses are more easily translated into ordered a step which is defined as the process model. The process model allows data and tools to be linked together in a user-defined sequence that structures automated geoprocessing tasks such as buffering, converting, overlaying or selecting data. The developed process model are viewed and edited in the Model Builder window. This is basically the main benefit as different analyses can be performed by changing the value of parameters in the query builder tools and effective decision can be made quickly.

Analysis
Basically a big percentage of study area is open land and used for agricultural purpose. The study area also exhibits karst geology, which is characterized by caves, sinkholes, and many surface streams. Karst systems are vulnerable to contamination. To assess the status of the study area as an agricultural area from a resource perspective, three main factors are considered: physiography, soil capability, and climate. The combination of soil characteristics, climate, access to water, and topography, the area become a unique area of specialty crop production. In these vast agricultural areas for the growth of the crops, mineral fertilizer and animal manure and to control unwanted Scenario I; At first the buffer distance changes to 500 meter and the slope value remain as the original slope as 5-10 degree. In this case, the agricultural land that is located on steep-slopes and within this stream buffer is most vulnerable to contamination as the most of the run-off these area are responsible for groundwater contamination through infiltration and discharges to the nearby streams. But, the buffer distance 500 meter around the stream surface is comparatively increase redundant cost of protection measures than 300 meter buffer distance around the stream surface. Figure 16 shows the display map for this scenario.  Figure 16 Vulnerable sites for Scenario I Scenario II: In the second scenario, the slope is changed in between 1-3 degree and the buffer distance remains the same as SOOmeter. In this case as the value o f the slope is not too high, the amount o f run-off which basically contains the agricultural chemicals, come from the area o f this slope will also be little, drain into the stream surfaces. The run-off infiltrates to the area o f this slope which ultimately led to less contamination compare to the original model. So the agricultural lands that are located on these slopes and within stream buffer are not very significantly responsible for the contamination. So, to take the protection measures in this area will not be appropriate decision. Figure 17 shows the display map for this scenario.  Figure 17 Vulnerable sites for Scenario II Scenario III: In this scenario, the slope value lies between 10-15 degree and the buffer distance remain as the original value. In this case, the agricultural land that is located on this most steepslopes not much remarkable. That is why contaminated area is less than that found in areas lies between 5-10 degree slopes. Figure 18 shows the display map for this scenario.  Figure 18 Vulnerable sites for Scenario III 4.6

Comparison Table
The study solved various tasks with different scenario on the model builder process. Table 5 below listed the quantity o f contaminated area and a statistics associated with different alternatives.

Results
The value of two parameters slope and the stream buffer distance are defined from MOE (Ministry of Environment) guidelines. 300 meter buffer distance and 5 to 10 degree slope value is most appropriate value for the groundwater protection model as we see on the comparison table that steeper slope giving less contaminated area.. The resulting feature class added to the map (see Figure 19) and to highlight the identified areas, the model results layer ( miahd Figure 19 Vulnerable site In the model green areas of results layer are the most vulnerable site for contamination. After getting the model output, tlie model_results will be validated. The information about the study area will be collected as the area is really affected with agricultural contaminants and then match with the identified areas and taken remediation measures.

Discussion
Natural systems (for example, biological, geological, and ecological systems) and their relevant phenomena are very complex; therefore, it is practically impossible to model such systems perfectly, and o f these models requires simplification and approximation. Modeling efforts cannot give positive answers if data about the physical system being modeled are not properly taken into account at every stage of the model development. So, the data accessibility is fundamental issues in terms o f sources o f data; data collection, conversion, and integration, and also data capture cost and time for environmental modeling applications using GIS tools.
In Arc GIS the Model Builder interface provides a graphical modeling framework for designing and implementing geoprocessing models that can include tools, scripts, and data. The data required for developing groundwater protection model and analyses of this project are slope data, stream data, watershed data, and agricultural data. In this regard the types of data collected are DEM data, land use data, stream data, and municipal boundary data. Actually it takes more time to arrange these data based on project requirements comparative with the model development processing time. The watershed data and slope data are created from the DEM data and the agricultural data from land use data. So, it is required to convert the DEM data and integrate all o f these data to perform the desired operations.
Digital Elevation Models (DEM) is data files that contain the elevation of the terrain over a specified area, usually at a fixed grid interval over the surface of the earth. The intervals between each o f the grid points will always be referenced to some geographical coordinate system. This is usually either latitude-longitude or UTM (Universal Transverse Mercator) coordinate systems.
DEMs come in different scales and resolutions. The closer together the grid points are located, the m ore detailed the information will be in the file. The details of the peaks and valleys in the terrain will be better modeled with small grid spacing than when the grid intervals are very large.
Elevations other than at the specific grid point locations are not contained in the file. The DEM file also does not contain civil information such as roads or buildings. The DEM does not contain elevation contours, only the specific elevation values at specific gnd point locations.
In the physical sense, the notion of scale refers to the resolution, defined by equivalent length or area that represents scaled field reality. In a GIS, analysis is done at the resolution of the data, not at any display scale. Resolution is the degree to which closely related entities can be discriminated. Resolution also limits the minimum size of feature that can be stored. Raster data is stored as (usually square) pixels, which form a grid or mesh over an area of the earth. The size of these pixels determines the resolution of the raster, because it is impossible to store anything which falls 'between' the pixels.
In this project the DEM data are obtained from GeoBase at a scale of 1:50,000. To develop the model all dataset should be converted to personal geodatabase. In ArcGIS, Arc Toolbox is embedded in Arc Map and Arc Catalog. Arc Toolbox contains a comprehensive collection of geoprocessing functions; among these functions data conversion is most fundamental. Using the data conversion tools the DEM data is ultimately converted as per required to slope raster data, polygon data, and then find watershed data using hydrology tools. The dataset in this stage appears in same format as vector format. The Arc Catalog application organizes and manages all GIS information such as maps, globes, data sets, models, metadata, and services. All vector dataset then converted to personal geodatabases using Arc Catalog. The personal geodatabse is finally used to model development.
In the model result layer which is displayed in Arc Map, the highlighted areas are most vulnerable to contamination. In the process model by setting the SQL expression parameter for the Make Feature Layer tool as a variable and exposing it as a model parameter. By replacing the expression with different parameter value, various analyses are done and compare with the original model.
So, from analyses it can be said the effort to build the model with the parameter such as slope value and buffer distance around stream are 5 to 10 degree and 300 meter are most appropriate for taking protection control measures in the study area.

CONCLUDING REMARKS
Today, agriculture in Ontario is among the most ethcient in the world, with low production costs and high safety and quality standards. Niagara is an integral part o f the Ontario agricultural economy. Historically agriculture provided an impetus for growth in the area and it continues to m unicipal water; therefore use of groundwater for irrigation is common. Theoretically, there is unused capacity within the regional aquifers as the current use is only 15% o f the recharge at regional level (Regional Municipality of Niagara, 2003). The bed rock wells in this region do not contain good water qualities. Agricultural inputs such as fertilizer, livestock manure, and pesticides have caused water contamination when improperly stored, applied or disposed of. There is also concern that certain bacterial, ninate. and high sulfur concentrations exceed drinking water guidelines in surface or groundwater, there may be negative health effects. So, it is now evident that ground water is seriously vulnerable to pollution and depletion due to anthropogenic activities in this region. As water quality affects Niagara's economy. Peoples need clean water for production and for drinking purpose. Property values can decrease near waterways that are heavily contaminated. A decrease in water quality also means an increase in the cost ot water treatment for human use. But the agricultural land of Niagara cannot be replaced; it is amongst the best o f a limited supply.
Groundwater must be protected since ground water is an integral part ot the water cycle and it will carry contaminants and pollutants from the land into the lakes and rivers from which other people get a large percentage o f their freshwater supply. In dry periods, the flow o f some streams may be supplied entirely by gi'oundwater. Protecting the ground water from contamination will require thoughtful management and cooperation on the part of citizens and various levels of government.
Land use planning is, in many cases, the best instrument available for protecting aquifers which still contain good quality water. If potential sources ot contamination are kept from locating over critical recharge areas, the risk of contamination can be greatly reduced. Industries, farmers, and homeowners located over ground water supplies need to practice good housekeeping with respect to the use and disposal of chemicals. In order to combat water pollution, it is necessary to locate the most vulnerable areas of a watershed.
In recent years, considerable interest has been focused on the use of GIS as a decision support system. The use of GIS as a direct extension of the human decision making process-most particularly in the context of resource allocation decisions is indeed a great challenge and an important milestone. The conventional way of most study is less accurate and more timeconsuming process as it has more dependent and independent variables. But GIS can handle the larger volume of spatial & non-spatial data and which is capable of doing complex analysis. GIS is the latest technology and tool, which can produce much more accurate results quickly & effectively.
Spatial Decision Support Systems (SDSS) are a computer-based system designed to assist decision making. Typically, such a system will include spatial data relevant or the decisions, analytic tools to process the data in ways meaningful for decision makers, and output or display functions. Thus, an SDSS has considerable overlap with the functionality of a geographic information system (GIS).According to the National Centre of Geographic Information and Analysis (NCGIA) Core Curriculum in Geographical Infonnation Systems, an SDSS is an "interactive, computer-based system designed to support a user or group in achieving a higher effectiveness of decision making while sob. ing a semi-structured spatial decision problem". There are many examples ot SDSSs for specitic decisions in the environmental domain, particularly in the areas of crop, livestock, tlood. and forest management.
Spatial decision support tools require environmental models both as sources of data and as key tools to guide decision making. An SDSS requires delivery of at least some foundation data, as the expertise needed to create and assemble these data is high and the transaction costs o f doing so steep, but the opportunity to pay this cost only once is of enonnous benefit to multiple users.
Besides providing foundation data and a core tool set, key features of the SDSS include link to auxiliary database and documentation, and the ability to incorporate additional, applicationspecific tools, including various types of highly specific, tailored, environmental models.
M odels are a particularly useful addition to Arc GIS. Arc CIS Desktop provides a geoprocessing fram ework o f tools that can be run in several different ways, including through dialog boxes in Arc Toolbox, as inputs to models in Model Builder, as commands in the command line, and as functions in scripts. This framework facilitates the creation, use, documentation, and sharing o f geoprocessing models. The two main parts of the geoprocessing framework include Arc Toolbox, an organized collection o f geoprocessing tools, and Model Builder, a visual modeling language for building geoprocessing work flows and scripts.
This report developed a groundwater protection model using Model Builder Window o f ArcGIS 9 and discussed how identity the steep-sloped agricultural fields of the study area which is susceptible to contaminate the groundwater by agi'icultural chemicals through precipitation and which is discharged in springs, streams, lakes, or wetlands. It did not address the issues related to the policy level. Improved management practices and a proper Nutrient Management Plans (NMP) can be applied in that area that can help to protect ground water contamination. Specific practices, which include prudent livestock and manure handling, balanced use of fertilizer, fuel, pesticides, and sustainable soil management will enhance water quality. Further environmental investigations, including secondary source reviews and field investigations will be required to generate best vulnerable areas, assess the impacts and best management practices.
Finally, some recommendations can be established as follows: • The agricultural land is a non-point source of groundwater contamination in Niagara.
• Once the aquifers are contaminated they become very difficult and costly to remedy and in m ost cases are abandoned. Protecting groundwater resources from pollution is therefore essential for its proper management and preventing probable hazards.
• In this regard ArcGIS 9 provides new tools to build protection model to study groundwater contamination issues o f various watersheds that perfonns multiple geoprocessing operations.
• In this project the intention o f the protection model is to define the areas o f the study areas where the run-off from the steep-sloped crop fields is one likely source o f groundwater contamination by agricultural chemicals.
Areas defined through the groundwater protection model are most vulnerable to contamination of groundwater as the run-off infiltrate through different soils and possibly recharge an aquifer or contribute water to a pathway delivering water to an aquifer.
Groundwater recharge is the portion of infiltrating water that will move downward through the unsaturated zone. When infiltration reaches the water table it becomes groundwater recharge. Recharge replenishes water in aquifers, or is discharged in springs, streams, lakes or wetlands.
Assessing the quality of a model is called validation. Model validation is possibly the most important step in the model building sequence. So, in this study the information about the study area will be collected as the area is really affected with agricultural contaminants and then match with the identified areas and taken remediation measures.
Different analyses should be done to change the value of parameters of the model and compare with the original model. After analyses effective decisions from the model output are taken.
After developing the final groundwater protection model of the study area the improved management practices and a proper Nutrient Management Plans can be applied in that area that can help to sustain.
For further study the model and its process can be modified and adapted for other studies as for example to investigate the potential sources of runoff from petroleum products in a watershed.