MSU LIBRARIES m RETURNING MATERIALS: PIace in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date stamped beIow. THE INFLUENCE OF SAND AND GRAVEL EXTRACTION 0N URBAN DEVELOPMENT BY Lisa B. Holzman A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Resource Development 198R ABSTRACT THE INFLUENCE OF SAND AND GRAVE]. EXTRACTION ON URBAN DEVELOPENT by Lisa R. Holzman Land use changes in the vicinity of thirty-nine sand and gravel extraction sites in Oakland County, Michigan, were examined using the microcomputer-based Earth Resources Data and Analysis System 800 for the period 1957-1980 to determine: (1) patterns of urban development in the vicinity of extractive operations; (2) the sphere of influence of extraction sites on surrounding development; and (3) the relationship between site characteristics and the identified development patterns and spheres of influence. The general pattern observed was one of increased development with distance from the site. This pattern existed for an average distance of 686 meters. Beyond this point development trends were similiar to those in surrounding areas. Due to the fact that most sites were located at the outer fringes of urban centers, it is wobable that this observed development pattern resulted from urban sprawl. The increase in development over time in the vicinity of extractive operations supports the idea that extraction has a neutral impact on urban development. The existing generalizations that sand and gravel operations discourage urban development were not substantiated by this research. To D. B. for keeping me going! 11 ACKNW LEDGMENTS I would like to take this opportunity to express my appreciation to those individuals who have helped me with various aspects of this project. First, my thanks to Peter Kakela, Department of Resource Development, for providing guidance, support, and financial assistance throughout my entire stay at MSU. Also, my other committee members; Anthony Bauer, Department of Landscape Architecture, who fostered m interests in sand and gravel extraction, and Milton Steinmueller, Department of Resource Development, who did much to broaden my horizons. Special thanks go to Russ Kruska, CRIBS, for helping me with the analysis section of this project. Also, to the other people at CRIBS for providing guidance and financial assistance. As well, thanks go to Jo-ellen Darcy for editing this paper. Last, but not least, my family, for providing their support through my entire education experience. LRH June, 198A 111 TABLE OF CONTENTS List of Tables.........O0......O...OOOOOOOOOOOOOOOOOOOO0.0... List Of FinQSOOCOOOO0......O....0.0...OOOOOOOOOOCOOOOOOOOOO Chapter I. IntrOduction. O O I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O The Rese ”eh Pm blem O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O BaCRSI‘oundoooooeooooo000000..0.0000000000000000.cocoa... The mm” or the studYOOOOO0.00.0.0...0.00.00.00.00... Chapter II. Literature Review............................... Introduction............................................ Sand and Gravel Extraction.............................. Location of Operations............................. Geologic Constraints.......................... Extracting and Processing Techniques.......... Accessibility of Harket....................... Nature of Economic Market..................... Government Restrictions....................... Impacts of Operations.............................. Identification and Mitigation................. Company Planning to Mitigate Impacts.......... Community Planning to Control Impacts......... iv vi vii 1O 1O 11 11 1h 16 Urban Development....................................... Suburbanization.................................... Residential Development............................ Chapter III. Method......................................... menieHOOOOOOO0.000.000.0000.COOCCOCOOOOOOOOOOOOOOO0.0. Determination of Study Area Boundaries.................. Land Use Interpretation................................. Analy8180000000000000000.0.0....OOOOOOOOOOOOOOOOOO0.0..O sources or 818300.00...OOOOOOCOOOOOOOOOOOOOOOOCOOOOOOOOC smaryOOOOOO0.0000000000000000000000COOOOOOOOOOOOOOO0.0 Chapter IV. Results and Interpretation...................... Introduction............................................ Results................................................. Interpretation.......................................... Patterns of Urban Development...................... Sphere of Influence Pit Characterist1CBOOOOOOOOOOOOOOOOOIOOOOOOOOOOO... Chapter V. Summary, Conclusions, and Recommendations........ serOOOOOO00......00....0.0.0...OOOOCOOOOOOOOOOOOOOCO concluaions.OOOCOOCOOOOOOOOOOOOOCOOOIOOOOIOOOOOOOOOOOOOC Recommendations For Future Research..................... prndixOOOOOOOOOOCOOOOOOOOOOOOOOOOOOOOOOOOOOOCOOOOOOOOOOOOC. References.O.0.O..0.IO.00.000.00.00...OOCOOOOOOOOOOOOOOOOOOOO 18 18 18 22 22 22 26 32 37 N2 ”3 ‘33 N3 115 58 69 73 85 85 87 9O 93 95 LIST OF TABLES Table 1. Extractive Sites--Active Years.................... AN Table 2. Incomplete Searches............................... ”6 Table 3. Crosstabulation--AV26, 1980....................... 57 Table u. Spatial Development Patterns...................... 60 Table 5. Temporal Development Patterns..................... 6n Table 6. Rate of Development............................... 68 Table 7. Sphere of Influence............................... 70 Table 8. Pit Characteristics............................... 75 Table 9. Groups Based on Pit Characteristics............... 77 Table 10. Pit Group Statistics.............................. 81 Table 11. Statistical Comparison of Pit Groups.............. 83 vi Figure Figure Figure Figure Figure Figure 6. Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 7. 8. 9. 10. 11. 12. 13. 1h. 15. 16. 17. 18. 19. 20. 21. LIST OF FIGURES Location of Study Areas.......................... White Lake Avon Study Example of White Lake White Lake White Lake White Lake Avon Study Avon Study Avon Study Avon Study White Lake Avon Study Example of Example of Study Area, Extraction Sites.......... Area, Extraction Sites................ a Search.............................. Study Area-Land Use, 1957............ Study Area--Land Use, 196N............ Study Area--Land Use, 1972............ Study Area-~Land Use, 1980............ Area-Land Use, 1957.................. Areap-Land Use, 196N.................. Area-u-Land Use, 1972 Area--Land Use, 1980.................. Study Area--Land Use Distribution..... Area--Land Use Distribution........... a Distal Pattern-WN.................. a meim1 Pattern--w1200000000000000. Rate of Development-Wu.......................... Sphere Of Inflmnce.OOOOOOOOOOOOOOOOOO00.0.0.0... Sphere of Influence--Location Groups............. Sphere Of Inflmnce-éize Groups. 0 o o o o o o o o o o o o o o o Sphere of Influence-~Phase of Pit Development.... vii an 26 27 36 u? as 2:9 so 51 52 53 5:: 55 56 61 62 66 71 78 79 so CHAPTER I INTRODUCTION The Research Problem Public hearings concerning development of new sand and gravel operations often indicate that there is a widespread public belief that sand and gravel extraction discourages urban development. The research project discussed in this paper examined the validity of this belief. It attempted to answer the question: Does the presence of a sand and gravel pit influence patterns of urban development? In general, locational analysis research has examined and identified factors which influence the siting of a particular type of development. For example, the location of an industrial plant may be controlled by the availability of labor and raw materials, the type and cost of transportation, and the distance to market. In contrast, this research problem examined whether a specific type of development (i.e. , sand and gravel extraction) influenced the location of another type of development (i.e., urban development). The general conclusions reached in this study may be applicable to other study areas and to other forms of urban mining. Background In 1982, the value of sand and gravel production in the United States totaled 2.3 billion dollars (1982 dollars), accounting for 10.71 of total nonpfuel mineral production. Only stone, iron-ore,.and copper production ranked higher (111.95, 13.93, and 13.11 respectively) (US Bureau of Mines, 1982). In Michigan, sand and gravel accounted for 72.N million dollars, or 7.A$ of non-fuel mineral production, ranking as its fifth most important non-fuel mineral (M-DNR, 1983). Michigan's sand and gravel production came from between 300 and 350 extraction operations, most of which were owner-operated and located in the southern portion of the state, close to the major population centers (Walden, 1983). This illustrates an important characteristic of the sand and gravel industry. Due to the material's bulky nature, transportation accounts for much of the final cost: "In 1978, the value of sand and gravel at the pit averaged about $2.50 per ton. At haulage rates of 12 or 13 cents per ton mile, the price is doubled to a customer 20 miles from the pit site" (Worth, 1980). Sand and gravel is usually the primary sources of aggregate used by the construction and paving industry. It is used in Portland cement concrete or asphaltic concrete, as general fill in utility trenches and storm drains, for bringing houses and building pads up to grade, as a base course under highways, railroads, runways, and road surfaces, and as maintenance material for existing structures and roads. The dominant market is the urban center. Thus, the economic viability of a sand and gravel deposit depends not only on geologic conditions (nature, grade, and extent of the deposit), but also on distance to the market. ‘The necessary proximity of sand and gravel operations to the urban environment creates a conflict: although the community has need for low-cost sand and gravel, most neighborhoods do not welcome the presence of a sand and gravel pit. As a result, zoning for mineral extraction is often difficult, if not impossible, to obtain. Even when necessary zoning does exist, the extractor is usually operating contrary to the wishes of his neighbors. The extraction industry is usually seen as a negative impact on the community, where 'rapacious producers [are] avariciously violating mother earth and leaving a scarred landscape" (Malm, 1982). Neighbors must put up with an ever growing, gaping hole from which noisy equipment rips out dusty material, dumping it into noisy trucks which then rumble back and forth along community streets, endangering children, pets, and general peace of mind. While it is true that in the past sand and gravel operations were deserving of much criticism, the situation has improved. Modern mining methods can mitigate, if not eliminate, most of the negative impacts of extraction. Operations can be visually screened from.neighhors through the use of earth harms and landscaping techniques. Dust and noise levels can be reduced significantly by following appropriate extraction procedures and using quiet, well-maintained equipment. Problems caused by increased truck traffic can be controlled through the use of speed limits, specified hours of operation, and even re-routing. Progressive or phase rehabilitation can produce an appropriate landform by the end of the operation's lifetime suitable for agricultural use, housing developments, industrial or office complexes, or even creation of a *wildlife preserve. Often, the rehabilitated site undergoes such development even while extraction is continuing in another portion of the property. The end result of all of this is an unobtrusive operation, scarcely noticeable to the extractor's neighbors. Such well-run operations do exist, but they generally receive little public notice. That, indeed, is their goal. Instead, public opinion is formed by the traditional sand and gravel pit, highly visible in the past and regrettably still visible today. The closeness of sand and gravel operations to urban areas means that there is generally a ready market for properly reclaimed sites. , These tracts of land are suitable for housing developments, office complexes, playgrounds, and parkland and may therefore increase in value compared to pre-mined land. But, as Hole put it, "the only landowner who views a sand and gravel...operation in his neighborhood as a tolerable thing is the one who is selling or leasing his land for that purpose" (1970). Most likely, his neighbors do not share his opinion. Many residents do not realize that the property next to such reclaimed areas also increase in value (Jewett, 1975). Those who do recognize these future benefits may not be willing to wait the necessary ten to twenty years before such financial gains can be realized. Local residents are more concerned with the present, and the fate of property abutting on the operating sand and gravel pit. Will the presence of the pit attract other industrial uses to the area? Will unattractive strip development occur? Will the value of surrounding property decline? These concerns are often the basis for local opposition to extractive operations. The Purpose of the Study The research discussed in this report was exploratory in nature. It focused on the influence of sand and gravel extractive operations on general patterns of urban development. Within this broad context, three research goals were identified: (1) to identify and describe general patterns (spatial and temporal) of urban development in the vicinity of sand and gravel operations; (2) to define the limits (spatial and temporal) of these identified patterns, and hence delineate the sphere of influence of extractive operations; and (3) to relate certain site characteristics (location, size and phase of pit development) to the results of the first two analyses. Chapter II of this report examines the relevant literature which provided the background information for the study. Research methods are Ioutlined in Chapter III. Chapter IV presents and discusses the results obtained from the study. Chapter V summarizes the results, details the conclusions reached, and provides recommendations for future research. CHAPTER II LITERATURE REVIEW Introduction To appreciate the need for the present research, it is important to understand the directions related research has taken. Generally, however, there is a dearth of information examining sand and gravel extraction as an influencing factor on urban development trends. There is, though, a great deal of literature pertaining to the individual topics of urban development and to extraction of sand and gravel. It was this material which provided the background, and indeed the catalyst, for the research discussed in this paper. The available information falls into a number of categories: Sand and Gravel Extraction W i) Geologic Constraints ii) Extracting and Processing Techniques iii) Accessibility of Market iv) Nature of Economic Market v) Government Restrictions W 1) Identification and Mitigation ii) Company Planning to Mitigate Impacts iii) Community Planning to Control Impacts Urban Development Winn Woman The remainder of this chapter highlights the key points of each catagory. Sand and Gravel Extraction MW Any analysis pertaining to the sand and gravel industry must keep in mind one key fact: the location of sand and gravel deposits are fixed. Man's control over these deposits is therefore limited to determining which ones are exploitable, that is, which ones are economic to produce. The location of a sand and gravel occurrence was controlled by nature. Fast-moving water was needed to transport and concentrate the sand- and gravel-size particles. Most commercial deposits in the United States were laid down by glacial meltwater or streams during periods of above-average flow (Gillson, 1960; Bates, 1969). Pleistocene glacial ice scoured and transported billions of tons of rock and soil. When the ice retreated much of this material was left behind as unsorted till. Meltwater flowing from the ice sheets provided sorting action for the sediment load, leaving behind vast numbers of sand and gravel deposits. In or adjacent to mountainous areas, sand and gravel deposits are lain down by streams during peak-flow conditions. Modern-day or past streams characterized by steep gradients and large water volumes (i.e. during flood conditions) act to transport and sort great amounts of sand and gravel. Where speed or flow decrease, these materials are deposited. In the case of sand and gravel, operators are interested in occurrences of aggregate material which, when extraction, processing, transportation, and other associated costs are subtracted, will yield a profit after selling. Often only a fine line separates an economic sand and gravel deposit from one which is un-economic. The factors which define this fine line are: i) geologic constraints; ii) extracting and processing techniques; iii) accessibility of market; iv) nature of economic market; and v) government restrictions. Each of these factors are discussed below. 1) Geologic Constraints Geologic constraints are those factors that define the physical nature of a sand and gravel occurrence, including the nature and depth of overburden material; the thickness andlextent of the sand and gravel layer; and, the physical properties of the sand and gravel layer (including particle-size distribution, particle shape, mineralogy, durability [hardness and soundness], and cleanliness) (Gillson, 1960; Bates, 1969; Worth, 1980). Generally, an operator wants to have a minimal thickness of overburden, somewhat friable (freeable or crumbly) in nature, and therefore easy to remove. The greater the vertical thickness and the horizontal extent of the sand and gravel layer, the greater the possibility for profit. Geologic constrains are fixed. Man's use of sand and gravel is controlled by the geologic conditions laid down by nature. 11) Extracting and Processing Techniques Two types of extraction operations are commonly utilized for sand and gravel deposits, dry operations and wet operations. The method chosen depends upon geologic constraints, surrounding environmental conditions, cost, government regulations, and operator preference. In dry operations, extraction occurs above the water table. In Michigan, such operations generally take place in hilly terrain. An increasingly larger hole (open pit) is created, from which material is removed by power shovels or front-end loaders. Generally a small amount of overburden covers a relatively large quantity of extractable material. Wet operations occur when deposits are situated below the water table. In Michigan, such operations are generally found in wetland areas or in flat terrain. Extraction is carried out by dredging or dragline techniques. In some cases, both techniques are used. Dredging operations use a suction device to pump aggregate and water from the bottom of the pit. A dragline scoops up material from below water level, creating a lake. A number of post-extraction processes may be required before the sand and gravel are ready for market. Screening, crushing, washing, and combining of grade sizes may be necessary. These are usually dome on-site. iii)Accessibility of Market Market accessibility is related to two key factors; the availability of a transport medium, and, the distance to market. Generally, sand and gravel is transported by truck. Trucking costs are variable, depending upon the length of haul, the traffic encountered, and the size of the truck. Smaller trucks may be more economic to operate, but more trips are necessary to move a given quantity of material. The use of trucks also implies the presence of accessible, heavy-duty roads. 10 Most sand and gravel is used by the construction industry, the major market being the urban centers. Due to the bulky nature of the material, extraction sites must be close to the market, to minimize transportation cost. Unfortunately, this creates a major conflict: Generally 55 km [311.1 miles] is the maximum economic distance for hauling sand and gravel. Because of this constraint, deposits located near urbanizing areas should be those of the most immediate interest to both the construction industry and planner. However, the paradox here is that the wave of building and road construction, which has escalated the demand for sand and gravel products, is at the same time causing urban conflicts which make deposits less extractable....In the Denver, Colorado, metropolitan area for example, a recent survey estimated 8110 million metric tons of sand and gravel lay within 218 km of downtown Denver. However, 581 of these deposits were designated as inaccessible because they had been built upon or were too close to newly constructed residences to permit mining (Griggs and Gilchrist, 1983). iv) Nature of Economic Market The economic viability of a sand and gravel deposit changes with variation in supply and demand. With increase in demand, or decrease in supply, the value of sand and gravel rises. Thus, operators may be willing to incur greater expense in extractive operations. Smaller deposits may become feasible to mine. Lower quality deposits, requiring beneficiation or upgrading prior to selling, may also become cost effective. Sand and gravel further away, previously too expensive to transport, may be able to compete in light of increasing market price. v) Government Restrictions Government regulations also act as factors affecting sand and gravel production. Compliance with regulations may increase both the cost and time required to turn a sand and gravel deposit into an 11 operating extraction site. Zoning and land-use regulations may prevent mining activities from occurring on a particular piece of land. Rezoning to permit mining generally results in delay and added expense. It may also generate adverse public opinion. Regulations requiring mine and reclamation plans prior to any development also add to the company's incurred cost in dollars and time. An operator may be hesitant to develop a sand and gravel operation if he has reason to believe that it will become a controversial issue with local residents. W i) Identification and Mitigation Much work has been directed towards identifying the negative impacts of sand and gravel extraction. Impacts include, but are not limited to, - noise - dust/air pollution truck traffic water pollution (surface and ground water) wildlife/plantlife aesthetics (visual quality, etc.) attractive nuisance/site safety economic (property values, etc.) - postmining landform/land use (Jewett, 1975; Coates, 1975; COSMAR, 1980; Banks et al., 1981) Although most are common to all types of surface mining, the proximity of sand and gravel to the urban environment results in differing emphasis. Also, the degree of severity of each impact varies from one site to another. Major concerns often revolve around visual impact, increased truck traffic, economic impact, and postmining landform/land use. These impacts are primarily blamed for attracting undesirable types 12 of development. Little work has been done in identifying positive impacts. The literature also examines techniques for mitigating the identified negative impacts. Visual impact can be minimized through the use of earth berms (both natural and man-made), landscaping, and an eye-pleasing site layout. General maintenance or grounds-keeping can also improve site appearance. Buildings and machinery should be kept clean and painted regularly. Wherever possible, paint color should blend in with the natural surroundings. Dust levels can be reduced by paving major haul roads, watering or chemically controlling on-site dirt roads, washing all truck bodies before leaving site, and tarping loads of fine grained material. Progressive rehabilitation will minimize the amount of disturbed land, thereby aiding in dust control. Noise levels can be reduced through equipment modifications and reduction of gradients of on-site haul roads. Full scale operations should be limited to “normal“ working hours. Some researchers believe that there is a correlation between noise and visual appearance. As noise levels increase, so does unsightliness. The impacts of increased truck traffic can also be minimized. Specific truck routes should be planned to avoid residential areas wherever possible. Operating agreements and payment procedures can be used to control truck speed and driver courtesy. Impacts on water systems can be minimized by controlling discharge from the site. Sediment ponds can be used to remove particle loads from pumping water before it is recycled into ground water. Oil and chemical 13 spills should be contained to prevent contamination of water. Monitoring for possible water'pollution can also be undertaken. Wildlife and plantlife should also be protected. Impact assessment, carried out prior to any site development, can be used to assist in planning. Once operations begin, efforts should be made to minimize wildlife and vegetation disturbance. Menitoring can be carried out to detect any unexpected problems. Public safety must be provided. All extractive operations should be identified by signs. Hidden truck intersections should be clearly marked. Fencing should be used to prevent entry onto the site. Much work has been directed towards site reclamation. A number of studies have been carried out which inventory sand and gravel operations, identify successfully reclaimed sites, and outline the procedures used to achieve success (Coates and Scott. 1979; McLelland et al., 1979; Marshall, 1983). Also, a number of conferences have been held on reclamation (Thames 1977; Schaller and Sutton, 1978; Bauer, 1982) providing mam examples of successful rehabilitation of sand and gravel pits. In general, the emphasis is on progressive or phase rehabilitation which minimizes the amount of disturbed land at any given time. This also reduces the amount of earth moving necessary, which in turn lowers the cost of rehabilitation. The aim of rehabilitation is to create a final landform appropriate to the surrounding area, and suitable for a number of possible land uses. If a final land use has already been determined, reclamation can be planned to create the necessary landform. Post-mining landforms and land uses include farmland, playground, parkland, housing developments, industrial or office complexes, and wildlife preserves. 111 The impact of sand and gravel operations on property value is controversial. Research carried out by some realtors show that: there has not been a significant difference reflected in the market between the prices of homes which were located immediately adjacent to and overlooking the mining operation and those that are subject to similiar influences except for the fact that they are somewhat remote from the mining operation and they are not directly overlooking the--the activity (Treadwell, 1983). A study carried out at Northwestern University (Radnor et. al. , 1981) indicated that blasting from quarry operations did not have a significant effect on property values. Any impact on housing costs was minimal compared to all other influences that affect the desirability of a home. Most property owners disagree with this conclusion. If, indeed, such an impact exists, it is probable that an operation which minimizes negative environmental and aesthetic impacts would also reduce negative economic impact . 11) Company Planning to Mitigate Impacts A number of studies have been directed towards guiding companies in their planning of community-acceptable sand and gravel operations. Writings in this category usually discuss such topics as government regulations, community concerns, pollution control, reclamation, and company-community relations. A number of key ideas are stressed. First, the company should be aware of community concerns when planning an extraction operation. As well, they should be willing to deal with these concerns. Often, the best means of doing this is by working "with" the community. To work best, community involvement should be a two-way street. The operator should explain the need for sand and gravel, how it is used everyday by everyone, and what the 15 difficulties are in mining it. He should also be prepared to discuss specific plans aimed at alleviating local concerns.... Many operators feel that the less the community knows about the mining plans the better. This approach may have worked in the past but, in most cases, will not work today....Enabling citizens to voice their concerns and suggestions will generally help to avoid conflicts and problems at a later date (Banks et al., 1981). The industry has initiated a number of programs aimed at increasing company understanding of the need and methods available for mine planning, especially in regards to site beautification and reclamation. In 1963, a research project was sponsored by the National Sand and Gravel Association and carried out by the Department of Urban Planning and Landscape Architecture, University of Illinois. Completed in 1970, this five part study examined the fundamental techniques and problems associated with progressive rehabilitation of sand and gravel extraction sites (Bauer, 1963; Johnson, 1961:; Jensen, 1965; Baxter, 1966; Pickels, 1969). Case studies were used to demonstrate the techniques and problems discussed. In 1972 a research study examining on-site beautification programs was sponsored by the Southern California Rock Products Association and the Southern California Ready Mix Concrete Association. It studied beautification of future operations through an examination of prototype situations and the landscaping of existing sites (Carreiro, 1975). The sand and gravel industry has also set up an annual competition to advance work in mine planning and after-use design. Undergraduate and graduate students in landscape architecture are invited to send in site designs. Students "use existing or proposed crushed stone and sand and gravel sites, evaluate the assets and liabilities of the operation, than 16 propose a beautification program that leads to a final reclamation proposal" (Carter, 1982). Originally co-sponsored by the American Society of Landscape Architects and the National Crushed Stone Association, the competition now has a third sponsor, the National Sand and Gravel Association. iii) Community Planning to Control Impacts Information in this category is usually directed towards land use planners, usually on a local, township, county, or state level. Emphasis is on three main points: (1) sand and gravel is often a limited resource and needs to be protected; (2) the public has a right to minimum nuisance during sand and gravel operations; and (3) once extraction is complete, the affected site must be restored to an appropriate landform (Worth, 1980). The high cost associated with transporting sand and gravel means that extraction sites must be close to the urban area. But, as urban developmnt occurs, a number of problems arise. As a community expands, it may meet or even surround what was once a remote extraction area. Thus the problem of impacts arises. Housing units may be built over the top of potential sand and gravel deposits, thereby preventing extraction of a valuable resource. Local land use boards need to be aware of these problems, so that planning can protect both limited sand and gravel resources and the members of the community. Areas which contain valuable sand and gravel resources can be set aside in special extraction districts to allow for future extraction. This concept is the basis for Ohio's Critical Mineral Resource Areas (CMRA) (Leone, 17 1982) and the Sand and Gravel Extraction Districts of Orange County, California (Evans, 1973). In such areas, mineral extraction is the preferred use. incompatible land uses (i.e. housing) are directed away from these regions. Local planning boards should also be aware of the 'state—of-the-science' in sand and gravel extraction. Planners should fully understand the potential impacts of such operations. The granting of an extraction permit, and extensions of such permits, should outline a set of operational standards which the operator must follow. Such standards should not only consider public and environmental impacts, but also reflect what is economically feasible for the operator. Finally, local planning boards should be aware that sand and gravel extraction is only a temporary land use. Numerous post-mining land uses are possible. While it is often difficult to envision, prior to mining, what the final land use should be, it is possible to envision the final landform. Reclamatation allows for the creation of a landform which is compatible with the surrounding landscape and suitable for a number of different uses. Sand and gravel extraction should be seen as an opportunity to create a more desirable landform than that which previously existed. Such a concept was evident in a proposed mining operation in Elgin, Illinois (Coates, 1982; Malm, 1982). When a large, high-quality, aggregate deposit was discovered on a site proposed as a major recreation area, the Elgin City Council worked with a geologic consulting firm and a landscape architecture firm to identify the desired final landform. The final landform was to have the variation in topography necessary for the desired recreation area. A mining plan was 18 created to bring about this desired landform. Included in the plan of operation was non-extractive excavation and landshaping. Urban Development mm A number of factors are believed to have stimulated suburbanization in the United States (Butler, 1980). The development of ghettos in sections of large cities is believed to have increased the movement of more prosperous families to the suburbs. Federally funded urban renewal programs have resulted in the conversion of much of the older residential sections of downtown areas into office and government space, high-rise apartments, and public housing. The improvement of transportation facilities and the availability of low-priced utility services in outlying areas has also increased suburbanization. One key point should be mentioned concerning the direction of suburbanization. In general, the character of development remains constant as one moves away from the city center (NAHB, 1958). If initial development northwest of the city center was mainly high-value residential, successive outward extensions are usually.of similar character. Therefore, this would be a poor direction in which to locate a low-cost housing project. The reverse situation would also hold true. W The suitability of a site for residential development depends on a number of factors, both natural and man-made. Natural environmental conditions which should be examined include climate, topography, 19 geology, hydrology, soils, vegetation, and wildlife. Man-made conditions which should be considered include the availability of public utilities and services, view, noise, external odors, property acquisition, and government regulations and restrictions (NAHB, 1981). Although overall climatic conditions are generally not a planning issue, variation in localized topoclimatic conditions may be significant. Solar radiation, prevailing wind conditions, topography, slope aspect, vegetation, soil moisture, and the location of large water bodies may all influence heating and cooling costs, determine level of human comfort, and promote public safety (Fabos and Caswell, 1977). The physical characteristics of the site, degree of slope, depth to bedrock, depth to water table, soil drainage, soil bearing capacity, stoniness, erodability, and topsoil quality influence the cost of development. The developer is affected as his costs include any expense required to overcome undesirable natural conditions. The home-owner must bear any expense resulting from repeated water damage, erosion, frost heave and other consequences of poor site selection which necessitate post-construction site improvements (Fabos and Caswell, 1977). The availability and adequacy of public water supplies, sanitary and storm sewers, and lines for telephone, electricity, oil, and gas services all influence site selection. Access to schools, churches, local shopping centers, and recreation facilities is also important. The presence of any of the above features increase the suitability of the site for development. Eigh'noise levels, obnoxious odors, and unattractive surroundings all decrease site suitability. Property availability must also be considered. Ownership and price influence 20 suitability, as do zoning restrictions and other government regulations. Adjacent land use was once included as another man-made condition which impacted subdivision location. The National Association of Home Builders (NAHB, 1958) suggested that airports, industrial uses, railroads, cemeteries, poorly developed subdivisions, and shack development all lowered the desirability of adjacent land for residential development. Airports were considered to be extremely undesirable neighbors for high class residential use, especially within two miles or under approach zones. This belief was partly based on the May, 1952, Report of the President's Airport Commission (PAC, 1952) which recommended zoning near airports to restrict public and residential development. Not only would this prevent the erection of tall structures which might hinder air traffic, but it would also protect homeowners from the nuisance (mainly noise and vibration) and possible hazards of overflying aircraft. Later reports, mainly by private organizations (i.e., one by Roy Wenzlick and Co. and one by Herman O. Walther), showed that the issue was not clear-cut. As a result, controversy now exists as to whether or not an airport does create a serious detrimental influence on residential development (NAHB, 1958). The similarity between the airport issue and the issue of this research paper cannot be overlooked. Like the airport issue, this study questions the influence of a specific type of development (i.e., sand and gravel extraction) on the location of another type of development (i.e. , urban development). It is possible that the conclusions of this study may also be significant to the airport issue. The following 21 chapters detail the method, the results, and the conclusions reached in this study . CHAPTER III METHOD Overview This research analyzed thirty-nine sand and gravel sites in Oakland County, Michigan. The location was chosen because of its high concentration of extractive operations and because it was highly accessible to the researcher. Once the study area was defined, land use in the vicinity of the sand and gravel extraction sites was determined for four years, 1957, 19611, 1972, and 1980. This information was then analyzed using the Earth Resources Data and Analysis System 800 (ERDAS 800) to identify possible patterns of development around each extraction site. Wherever possible, the area of influence of the extractive operation was defined. Attempts were made to relate a number of site characteristics (location, size, and phase of pit development) with the results obtained. Determination of Study Area Boundaries The delineation of study area boundaries was based on a 1:11000 mp drawn up by the Oakland County Planning Division. Entitled W Sim it detailed the location of all known sand and gravel pits (past and present) in the county (OCPD, 1982). Each pit was classified as being active, not-active, or redeveloped based on its status in 1982 Active sites were defined as those in which extractive operations were 22 23 currently taking place. Not-active sites were those where extraction had occurred but was not occurring as of April, 1982. These areas were vacant of other land uses. Redeveloped sites were defined as those on which extraction had occurred but were currently being used for new and different land uses (OCPD, 1982). In order to carry out a sequential study over time, it was necessary to examine pits in all three categories. To enable examination of impacts on urban development, pits in regions of differing stages of development were included. Thus, sites in highly developed areas, areas on the fringe of development, and areas beyond development were required. Thirty-nine pits were identified which fulfilled the necessary criteria of this study. These fell into three clusters on the basis of location. One cluster, consisting of 15 pits (5 active, 7 not-active, and 3 redeveloped), ran roughly parallel to and along the White Lake Township and Waterford Township boundary. A second, roughly spherical cluster of 8 pits (11 active and 11 not-active) occurred near the Orion-Pontiac Townships boundary. The last group formed a northeast widening wedge running from the southwest corner to the northeast corner of Avon Township. It consisted of 15 pits (7 active, 3 not-active, and 5 redeveloped). A distance of 1.5 km (0.9 mile) was marked‘off in all directions from each pit symbol to delineate individual pit examination areas. These examination areas were then joined together, creating the research area. For convenience, the research area was broken down into two, distinct study areas. The White Lake Study Area enclosed the first cluster of pits. The Avon Study Area contained the other two clusters. The boundaries of the two study areas are shown in Figure 1. Figures 2 2n me~“' . . 5.“. @wmm Lake Study Area We. .Avon Study Area Figure 1. Location of Study Areas 25 and 3 provide more detailed information of the White Lake Study Area and the Avon Study Area respectively. Each pit is numbered (2-110) to allow for ease of identification. Initially, one active pit (number M1) in Milford Township was included as a third study area. Situated in the center of the town of Milford it was believed to represent a site within a highly developed region. It was later dropped from the research project because it was too recent (post-1972) to allow for adequate examination over time. As no information or previous work could be found to suggest the magnitude of the region effected by a sand and gravel extraction site, the investigator examined the area around each site up to a distance of 1.5 km from the border of extraction. Land Use Interpretation Once the study area was defined, changes in land usage, between 1957-1980, were determined. In Oakland County this time span is represented by four series of airphotos: 1957, 19611, 1972, and 1980. For each of these years, land use within the study areas was determined and mapped at a scale of 1:21:000 (1"=2000'). The airphotos used are listed in Appendix A. All regions within the study area were assigned to one of the following eleven categories of land use; all of these are discussed later. Vacant and Agricultural Residential Commercial and Industrial Lakes Highway Special Uses: Golf Oakland University Pontiac-Oakland Airport Pontiac Silverdome 0 REDEVELOPED W4 SITE NUMBER I KILOME IERS Figure 2. White Lake Study Area, Extraction Sites 92 . ACTIVE A NOT ACTIVE o REDEVELOPED If}? ;;;_E\:’fl @3753 A... SITE NUMBER -. W_ _I_A _‘ _LH,_ ~_ 4‘ _. 1 1 J 4 WLI‘ '-"‘*-_ '““‘~._ ' " ’ ‘ i 5 I I MLDMIIERS Figure 3. Avon Study Area, Extraction Sites 28 Extraction Gravel Pit Lakes Land use maps are generally drawn on the basis of airphotos, deeds of ownership, tax records, platting maps, and other government documents. Land use categories vary, but generally differentiate vacant, agricultural, residential, commercial, manufacturing, industrial, recreational, public, and quasi-public property. Some of these categories may be further subdivided and some may be combined, depending on the purpose of the resulting land use map. Often ownership of the land is included as a basis of classification. This may not accurately reflect actual use. For example, public land use could include a large public park, a public golf course, a high school, a filtration plant, an airport, and a publicly owned housing development. On the other hand, a private school and a private golf club might be classified as commercial and an apartment complex as residential. For the purpose of this study it was believed that such classification schemes would not accurately reflect true land use and bias the results obtained. Thus, in order to obtain an accurate picture of land use, data were collected mainly from airphotos. Random verification was achieved through ground inspection and land use maps obtained from the Oakland County Planning Division (OCPD, 19611; OCPD, 1981). The heavy reliance was placed on airphoto interpretation for a number of reasons. First, ground inspection (done during the summer of 1983) could not accurately describe land use conditions in 1980, let alone in 1972, 19611, or 1957. Land use maps were only available for 19611 and 1981, which, although helpful, provided more detailed 29 information for those years than that obtained from the airphotos. When compared with data obtained for 1957 and 1972 (solely on the basis of airphotos) consistency over time was not permitted. Also, the land use categories used in the two maps differed from each other and from those used in this study. This created further complications. Therefore, little reliance was placed on the existing land use maps. The selection of land use categories was based on a number of criteria. First, the investigator was interested in a classification scheme which would reflect the research problem. Hence the necessity of separating sand and gravel extraction from other forms of development. For similar reasons, urban and commercial development were also isolated. Vacant land and land used for agricultural and forest purposes were combined due to the difficulty of accurately differentiating these from one another solely from airphotos. A number of special uses were identified: Pontiac-Oakland Airport, Oakland University, Pontiac Silverdome, and golf courses. These were isolated because of the investigator's belief that they might attract distinct development. This is not to suggest that such uses have a negative impact on development. Rather, the investigator based this decision on the idea that certain land uses require certain support facilities which may be reflected in overall development patterns. For example, the Pontiac Silverdome holds a large number of spectators. Parking facilities are therefore needed in its vicinity. Often the perimeter of a college campus is lined with bookstores, photocopy services, and coffee shops and restaurants. Nearby low-cost student housing is also found. It was felt that by separating these special uses such trends could be recognized if, in fact, they did occur. 30 Initial attempts at land use classification indicated that it was difficult to identify some individual representatives of certain catagories, especially when surrounded by one major land use area. For example, it was extremely difficult to isolate one house in the center of a commercial district. Even when this could be done, there was no means for determining if the property was still used for residential purposes, or if it had been converted to an office building or store. High-rise apartment buildings and office buildings were also difficult to distinguish between. The presence of a corner store or gas station. was difficult to isolate in a residential neighborhood. To eliminate this problem, it was decided to classify land according to a more general “character" of use. Thus, one corner store in the middle of a large residential area was not isolated. similarly, individual residential dwellings in a downtown business area were not identified. Attempts were made to accurately portray the land use along major roads and at major intersections. As was mentioned earlier, eleven land use categories were used. m included vacant land and land used for agricultural and forest purposes. Large parks (both recreational and wilderness/wildlife) were also included. Railroads and roads other than major highways were also included. The investigator was concerned with broad classifications of development, hence only two general types of urban development were identified. Residential included all land used for residential-type development. Uses such as single-family houses, multi-family houses, apartments, neighborhood parks, and schools were included. As mentioned earlier, individual neighborhood businesses and corner stores also have 31 been included. Inclusion of all of these land uses allows for preservation of a residential, or neighborhood, character. W included all business, commercial, manufacturing, and industrial uses. Once again, the occasional residential dwelling may be included. Lake included all mappable, permanent bodies of water. These regions were not available for development, although they may have attracted development to them. Rivers and streams were not included. W included only major road systems, specifically Michigan Highways 75, 59, and 2h. Grass medians between lanes and exit ramps were included. As discussed earlier, four special land uses were identified, £9.11, courses, the Pontiac-Oakland Am, Oakland mm, and the Pontiac mm. m included all land areas under current disturbance due to sand and gravel extraction. Each pit or group of pits was identified with a number to ease later analysis. Actual land use was determined for only four years: 1957. 19611, 1972, and 1980. The periods between these years were not examined. Therefore, any extractive activity occurring during these periods would not be noted. As a result, if the activity for a particular pit was confined to any of these time periods (i.e., 1965-1971), it would not be represented in the study. Also, should a pit cease operations during one interval (i.e., 1967), the actual year of cessation would not be pinpointed. Unless reactivated, the pit would not be represented in any of the study years which followed (i.e., 1972 and 1980 for a pit which ceased operations in 1967). W included all bodies of water accompanying extraction. These were within, or next to, a site of disturbance. Like 32 Lake, these areas were not available for development, although they may have attracted development. Only the larger bodies of water were included. Should a gravel pit lake remain after all other signs of disturbance were gone, it was thereafter classified as Lake. The result of this phase of the project was eight land use maps, four of the Avon Study Area (1957, 19611, 1972, and 1980) and four of the White Lake Study Area (1957. 19611, 1972, and 1980). Analysis The microcomputer-based Earth Resources Data and Analysis System 800 (ERDAS 800) was used to analyze the land use data. This system allows for input and manipulation of goo-referenced information, in this case land use data. Digitizing was used to assign numerical values to the mapped data. An x-y cartesian coordinate system was superimposed on all maps of the two study areas. The information contained in the four maps for each study area could then be described using the same x-y coordinates with the use of the digitizer. Reference points were chosen and defined in terms of x or y locations and a test point used to verify the accuracy of the set up. The reference points set up the right angle geometry for the digitizer and defines the’ coordinate system. This acts to "calibrate" the map for digitizing. The test point is located where the reference points cross, and it checks (1) the accuracy of superimposing the reference points and test point on the map, and (2) the accuracy of digitizing both the reference points and the test point. A maximum error of 12 meters for the Avon Study Area and 10 meters for the White Lake Study Area was allowed, accounting for human inaccuracy in 33 superimposing the coordinate system on each land use map. Such an error corresponds to 00.063 of each study area. All efforts were made to remain within 00.031 error, or 6 meters. Each land use map was placed on a digitizing board where information was recorded using a hand-held cursor device. Each specific land use category was assigned a distinct numerical value. For each mapped land use area, or polygon, the corresponding numerical value was entered, and its boundaries outlined by a series of points using the curser. Every time the cursor was keyed the corresponding x-y coordinates at that map location were entered into the computer. A special number on the cursor keypad was used to inform the computer to close the polygon when the starting point was almost reached. The region within the digitized boundary was therefore assigned to the specified land use value, and contained a finite number of x-y locations. A special progrml was then used to convert the digitized (x,y) data into gridded data with the same coordinate system. The grid system allows all geographical information to be represented by cells of a defined area or resolution. Therefore, the map can be represented by an array of x columns by y rows in the computer's memory in the form of a gridded or Geographic Information System (GIS) file. In this study, each GIS grid cell corresponded to a 211 by 211 meter mapped area (0.1423373? acres). Avon Study Area data were entered into a grid of 780 rows by 780 columns, and White Lake Study Area data into a grid of 652 rows by 1195 columns. Polygon data were converted in the order of digitization. If two or more land use categories over-laid one grid cell, the last to be entered was recorded as the grid cell value. 311 The grid cell size (211 m x 211 m) was chosen to minimize the error associated with such overlapping occurrences. It was also chosen so as to be able to record the smallest map areas which needed to be recorded, i.e. , the presence of an individual building. Each of the eight land use maps were digitized and converted to separate land use GIS files. Each GIS file was then checked and edited on a color display monitor to ensure that all mapped data were accurately recorded. Each land use category was assigned a specific color to ease verification. All errors were edited interactively on the color monitor. From the edited land use GIS files the investigator obtained values corresponding to the proportion of each land use found in the vicinity of each gravel pit. Successively greater distances from each pit were analyzed. In order to obtain this type of data, the SEARCH program (one of the analysis phases of GIS) was utilized. SEARCH is a proximity analysis routine that searches out from a specified class (attributed value, in this case a specific sand and gravel pit), creating a series of successive bands. These bands were created cell by cell, starting at the outer boundary of the class specified to search from, and growing outward. The search ended when a specified number of cells, in an outward direction, had been examined. New GIS files were created for each search (called search GIS files), while the original land use GIS files remain unchanged. For example, in a search of 6 cells from class of value 111, the first band would search out all cells one cell out from all values of 111 (i.e., next to a cell of value 111). The second band would contain those cells two cells away from all cells of value 1'1. The third band would search cells three cells away from cells of value 1'1. Successive bands 35 would form in a similar manner. The final band, band 6, would contain all cells 6 cells away from cells of value 1N. When more than one area, or polygon, of a specified class occurred, initial bands developed around each polygon. When the search areas overlapped, the bands were combined. In this study, this situation occurred when an extractive site had more than one, discrete, active sand and gravel pit. Figure '1 illustrates a search of 6 cells from two polygons of value 1'1. For this study it was believed that 1.5 km was a realistic maximum for the sphere of influence of a gravel pit. The size of the area which SEARCH examines depends on the number of cells specified. As mentioned earlier, cells for this study represented 24 m x 211 m. Thus, the search distance had to be a whole number multiple of 211. The actual search size was therefore 1512 m (63 cells). This distance was then broken down into nine smaller divisions. The investigator expected that any influence of the gravel pit on land use would decrease with increasing distance from the pit. Therefore, the divisions closest to the pit had the smallest incremental change. Divisions were obtained by grouping together search bands. The resulting distance divisions, or "rings” were then called Ring I through Ring 11. These were as follows: Ring I: 0-72 m (Bands 1-3); Ring II: 72-11111 m (Bands A-6); Ring III: 1411-216 m (Bands 7-9); Ring IV: 216-360 m (Bands 10-15); Ring 5: 360-5011 m (Bands 16-21); Ring VI: 5011-7114 m (Band 22-31); Ring VII: 71111-1008 m (Bands 32-111); Ring VIII: 1008-12u8 m (Band A2-52); and Ring 1!: 12h8-1512 m (Bands 53-63). The area around every extractive site was searched separately. For subsequent analysis, some of the gravel pits were grouped together as one extractive site. The pits within each group were close together, 111111 37 and were expected to have a joint influence on urban development. Within groups, the individual operations were often difficult to distinguish and sometimes appeared sequential in nature. The following pits were grouped together: W2 and W3; WA, W5, W6, and W7; W8 and W9; AV17 and AV19 (AV18 was never active during the years examined); AV23 and AV211; and AV35, AV36, and AV37. For each mapped year, searches were run on all extractive sites present. The results of the searches were then crosstabulated with the land use data. The crosstabulation program compared the search GIS files with the land use GIS files (CRIES, 19831). Therefore, for each mapped year, the land use GIS file was crosstabulated with the search GIS files for every extractive site within that study area. The computer calculated the land use distribution within each searched distance ring. A separate printout was then obtained for each mapped year of every extractive site. Results were given as the number of cells of each land use category within each distance ring. Percentages for each land use within each ring were also calculated. Sources of Bias The results of the analysis, and thus the conclusions of the study, may be biased in at least five possible ways. These were categorized according to their source: the data base, interpretations, cartographic, ERDAS, and numerical. Each of these is discussed below. Where ever possible, attempts were made to minimize the known biases. The data base for the study was airphotos taken between 1957 and 1980. Thus any distortions in the airphotos were included as part of the data. Airphotos result from projecting converging rays through a 38 camera lens. As a result, any variation in ground surface elevation would be recOrded with a scale variation and a displaced image position (Lillesand and Kiefer, 1979). Areas of higher elevation were closer to the camera and therefore appeared larger than similar areas at a lower elevation. Also, the tops of objects were displaced relative to their base. Displacement extremes occurred at the edges of photographs. In order to minimize such distortions overlapping airphotos were used. By carefully selecting airphotos, areas of interest were examined when centered on the image. The possibility of interpretational bias must be considered. Land use was determined from airphotos. Any misinterpretation of the airphotos would directly effect results. Due to the nature of the study ground verification was difficult. This was the main reason for defining land use categories based on the "character" of development. In this way the importance of small, difficult to identify, islands of development were minimized. This concept, in itself, would bias all values obtained for land use proportions. Ground inspection was used to verify that area character, as determined from airphotos, did agree with ground truth. As discussed earlier, only four study years were examined. Any pit which operated solely in the periods between these years would not be noted in this study. This might bias the results obtained. In order to prevent memory bias in interpretation, airphoto examination did not parallel time. The airphotos for 1980 were examined first, followed by 19611, 1957. and then 1972. For each time period the White Lake Study Area was examined prior to the Avon Study Area. This 39 was done to prevent back-checking by the investigator, either directly, from airphotos, or indirectly, through memory recall. Consistency of interpretation was important and a number of steps were taken to ensure this. First, all airphotos were of a scale sufficient for interpretation. Although actual airphoto scales varied between years, they were close to 1:24000 (1":2000'). Guidelines were set down to aid interpretation. For example, land use boundaries were not necessarily based on property borders. Land uses along roads were bordered by the road. Elsewhere, buildings generally defined land use boundaries. Large vacant areas behind buildings and parking lots were considered vacant, as were large areas between buildings. Within residential subdivisions backyards were classified as residential. In areas of strip or road development backyards were considered residential only if easily defined (i.e., by tree borders or fences) and only if small. The information obtained from airphoto examination had to be transcribed onto 1:2000 maps. A number of cartographic biases could have resulted from this. Any distortions on the airphotos would be preserved on the land use maps, i.e., scale variation or displaced image position. As mentioned earlier, efforts were made to minimize observance of such distortions. The land use areas drawn on the maps were 'eyeballed' into place. Because airphoto and map scales were similar it was hoped that placement bias due to 'eyeballing' would be minimized. Bias due to line width and drawing were difficult to avoid. Township base maps drawn by the Oakland County Planning Division were used to aid cartography. 110 Information could also be biased within the ERDAS phase of the analysis. Within the digitizing component two main sources of bias were possible. When the x-y coordinate system was superimposed on each land use map efforts were made to ensure accuracy. But, slight dislocation could arise. By allowing a maximum error of 00.06%, the amount of the dislocation was minimized. Digitizing was the sole means of entering land use data into the computer. A curser was used to trace land use boundaries, allowing x-y coordinates to be calculated. Although the digitizer itself is accurate to 0.001 inches, unavoidable imprecision in tracing land use boundaries was incorporated as part of the data by the computer. Each boundary was recorded by a finite number of x-y points. Thus, depending on the complexity of the boundary and the number of points used to describe it, a degree of estimation was also incorporated into the data. To minimize the error associated with such estimation, care was taken to use a sufficient number of points to adequately describe each boundary. Any other digitizing errors were corrected through editing of the GIS files. All of the digitized data were then converted into gridded (GIS) files. The grid cells were arranged in vertical and horizontal directions, at right angles to each other. Land use boundaries at any other angle were therefore approximated. Each cell (representing 211 m by 211 m) was assigned a single land use value by the computer. When two or more land uses overlapped one grid cell, the last value entered, not the value actually dominating the cell, was preserved. Errors resulted if the last value did not represent the "physically" dominant land use; however, the grid cell size was chosen so as to minimize occurrence of such a bias. As a result, small polygons, such as individual buildings, 311 are therefore over-represented, while the larger areas next to them, i.e. , vacant areas, are under-represented, because the small areas were digitized last. The SEARCH program could also generate certain biases. Each search went out 1512 meters from the outer boundary of the gravel pit. Therefore, land use data had to be provided for 1512 meters, in any direction, from the outer boundary of each gravel pit. In other words, no gravel pit should have been within 1512 meters of any border of the land use mapped area. This was not always achieved. The eastern edge of the Avon Study Area corresponded to the eastern edge of Oakland County. Land use determination did not go beyond this border. Therefore, searches around gravel pits near this border were not complete. Thus, the data produced may not have accurately represented conditions over 1512 m for a full 360 degrees around each pit. As a result, actual land use proportions would vary to some degree depending on the land use distribution of the “missing" seglnent or segments. A similar problem occurred elsewhere. For each pit or pit group, the actual area of current disturbance shifted over the time span examined. The boundaries of the study areas were determined using a 1982 map of extraction sites. If, at any earlier time, a pit was closer to the study area boundary, the possibility existed that the full 1512 meter examination area would not be preserved. Therefore, searches around these pits might also be incomplete, and thus not represent true conditions. Whenever an incomplete search occurred, the distance rings concerned were noted. All numerical data manipulation was based on numbers arising from crosstabulation of the search GIS files and the land use GIS files. In 112 converting grid cell numbers to percentages, rounding was done. The crosstabulation program rounded to two decimal places. Further manipulation of these numbers would result in error propagation. To prevent this, and also because of the limited resolution of graphing, further calculations were only carried to once decimal place. SI-ary The method used in this study consisted of three phases: (1) determination of study area boundaries; (2) land use interpretation; and (3) analysis using the microcomputer-based Earth Resources Data and Analysis System 800 (ERDAS 800). The results of these three phases are presented in the following chapter. CHAPTER IV RESULTS AND INTERPRETATION Introduction The results of the crosstabulation of land use GIS files (containing the eight land use maps) with search GIS files (containing the nine distance rings) detailed the land use distribution around all extractive sites. Graphs were used to facilitate interpretation of this numerical data. Interpretive analysis, directed at the research goals identified in Chapter I, was then undertaken. Results Of the thirty-nine extractive pits located in the two study areas, nine were never active during any of the four mapped years. Seventeen of the pits were active for only a portion of the study period. Only 13 pits were active throughout the study period. Table 1 lists the years when each extractive pit was active. As discussed in Chapter III, certain pits were grouped together for analysis. Pit groupings were as follows: W2 and W3; W11, W5, W6, and W7; W8 and W9; AV17 and AV19 (AV18 was never active during the study period); AV23 and AV2N; and AV35, AV36, and AV37. Pit groupings are also indicated in Table 1. As discussed in the previous chapter, complete searches could not always be achieved. This occurred when an extractive site was within 1512 meters of the border of the mapped area. The distance rings for ”A Table 1. Extractive Sites -- Active Years 195? 196A 1972 1980 W1 R e m o v e d f r o m s t u d y Grouped {W2 x x x x as W2 W3 x x WN x x x x Grouped W5 x x x x as W” W6 x x x W7 x Grouped W8 x x x x as W8 W9 x x x x W10 x x x x W11 W12 x x x W13 x W1N W15 x x x W16 x x x x Grouped AV17 x as AV18 AV 17 AV19 x x AV20 x x x AV21 AV22 Grouped {AV23 x x x x as AV23 AV2N x x x x AV25 AV26 x x x x AV27 x x AV28 x AV29 x x x AV3O AV31 x x x x AV32 AV33 AV3N x x x x Grouped AV35 x x x as AV36 x x AV35 AV37 x x x x AV38 x AV39 x x x x AVNO x 115 which the search was incomplete depended on the actual distance between the site and the border. Table 2 identifies which sand and gravel sites had incomplete searches. The table also details the year and the rings concerned. Eight land use maps were generated in this study. The maps for the White Lake Study Area are seen in Figures 5, 6, 7, and 8 (1957. 19611, 1972, and 1980 respectively). Figures 9, 10, 11, and 12 show the Avon Study Area (1957, 19611, 1972, and 1980 respectively). These maps are found in the pocket on the inside of the back cover. The land use distribution in the White Lake Study Area and the Avon Study Area for all study years are summarized in Figures 13 and 111 respectively. The results of the crosstabulation of SEARCH GIS files with land use GIS files were tabulated. The table for AV26, 1980, is reproduced in Table 3 as an example. These tables detailed the land use distribution around each pit or group of pits. They indicated variations in land use for the nine distance rings surrounding each extractive site. Separate tables were prepared for each year. For those pits which ceased operations during the study period the tables for post-extractive yearsalso identified the land uses which replaced extraction. Interpretation Prior to any interpretation of the study results, one key point needs to be clarified. As mentioned in previous chapters, thirty-nine extractive locations were examined for the period 1957 through 1980. These 39 operations were grouped into 21 pit in,” to facilitate analysis. Four specific years were examined: 1957. 19611, 1972, and Table 2. Incomplete Searches N6 Pit Year to 72 II 72 to 1AA Distance Rings (meters) III 1AA to 216 IV 216 to 360 V 360 to SON VI 50A to 7AA VII 7AA to 1008 VIII 1008 to 12N8 IX 12N8 to 1512 W2 wu W13 AV17 AV20 AV28 AV34 AV35 AV39 19611 1972 1980 1980 19611 1972 1980 1972 1980 19611 1972 1980 1972 1980 1972 1980 1957 19611 1972 1980 1957 19621 1972 1980 NNNNNRNX xxxxxxxx NXNflNKXN NNNXNXNN xxxxxxxxxxxxxxxxxxxxxxxx LR VACANT RESIDENTIAL COMMERIAL LAKE GOLF AIRPORT GRAVEL PIT LAKE EXTRACTION Figure 5. White Lake Study Area—~Land Use, 1957 Figure 6. 8R VACANT RESIDENTIAL , COMMERCIAL WVLAKE GOLF AIRPORT GRAVEL PIT LAKE EXTRACTION White Lake Study Area--Land Use, 1964 ’11. I IV////;' ,/ ”/CI/ VACANT RESIDENTIAL % COMMERCIAL , 35;; LAKE \\« GOLF AIRPORT GRAVEL PIT LAKE EXTRACTION Figure 7. White Lake Study Area-—Land Use, 1972 6T7 RESIDENTIAL COMMERCIAL LAKE GOLF AIRPORT GRAVEL PIT LAKE EXTRACTION or M ”1 2 7 3MILES Figure 8. White Lake Study Area——Land Use, 1980 OS U1 -4 \‘GRAVEL PIT \\\{‘:: LAKE EXTRACTION Figure 9. Avon Study Area—-Land Use, 1957 Figure 10. HIGHWAY Avon Study Area-~Land Use, EECOMMERCIAL < 1‘ r-mhnfimmnnl ,/,/’/ / ‘1 \\ 196“ 6 \\\ I] IL] 0 K D P.) BNHLES -9.c~rv. Figure 11. a saga-4:; W Th I II ~-IIIII|IIIIIIIIIII IIIIIIIIIIIIIIIIIII .,..,. . ., .. UNIVERSITY S ‘SlLVERDOME §E“‘T3GRAVEL PIT 1m» _ ., __ “‘ LAKE 0 1 2 3 MILES HIGHWAY EXTRACTION Avon Study Area—-Land Use, 1972 UNIVERSITY SILVERDOME GRAVE L PIT ... E LAKE 1 0 I EXTRACTION Figure 12. Avon Study Area--Land Use, 1980 3MILES v~\s.\ \\\\\\ \\ \(.\‘“2 ““““““ 53333 56 acqaanahunun on: u:uanuao&< hvsam c0>< .3, @009 snap 5.08%.“. I 9.3 E .920 g 85.225 mm 2.225 a .30 m it}: a 9.3 § 32888 M 328.81 ass IF: :I \\\\\\\\\\\\\\\\\\\\ .u\sll|lu|l|||l|\o\su\t\\\\\\\. §>D g g Ab Too. .ap cgsmam need .98F ‘0 ekxznn 57 mm: mum P110026, 1980 WHIDC Croast abulatiom-AV26 , 1980 Table 3 . ‘.'.ln--'n-.'.'o' '.0.' 0. 0 I. I.-.‘ 0.0.0.' 0.0 '.0.0" 0. .0.-. M. mmmw m mommm Jmfl.m mma . mm. m amm . mmm.m mm&_. mm. % namwm mmm . mmmw m maam I 3&8 m o. M“ m . 932 000 m 3“... 000 932 000 9n2m 000 000 m M. mmmw a amflmm gum m «mm m nmumm ”a. . mmm m 5.. . mm» a “nu . um... wwmm “ w Nara." 1 $30“ 1 ".0 N32 19 . n .3”... 000 631 . 00.0. 1 4.34.... 0.0.0. Ammmm Mm .mm . aflmmm mam m a“. m mm» m Mam . mmm . mam . mm» ..mmm.m wmm w.mmmw " "IA” "7 n .1 "MA. m 7K“! 3” m 2 00° 000 00° 00° 000 ” Mm mmm m mamwm a..mm a”. a .wa u my... mm. . mmm . mm. . mm. . mm... mmmw " a mm” 1 “”6 m ”5m ‘6. IN 9”... . 000. 000 00.0. . $00» “0.3.." _ 000 “ Wm mam m mmz m «ammo mm. . mmm m om. . mmmmm mmm . mm... mam . mmm ..mmmw u I. MAID “4.83" 62” 60 000 ‘4 00°“ 00° 00° 00° 00° 000" Mm moo m ammwm mummm aflm . mm. a ”mm . mm. . mm. . mwm.m.www.u._.m_..mmmm ” wss n73" maIm ms 000“ 53 000 000 0mm mmm .m ooom .m mam m mmu w flag a mmm...mmm.m mamm. mmm". mmm . aw... mm. a .u «.mmmw W22 “21 m1 U2 000 61 000 000 00.0. 0.00 chm . 000 u “m man m «mm m wmm . nmm . mm. a amm . mm. . mmm . mm» . ”mm m «mm . ..mm WI... ”21 17.. I. 000 «u... 000 000 00am 0.00 N“ 000 m «mm m mfiflwm mam . mm. . mam a ”a. . mm. . mum . mm. . mm. m mam . mm. W11 “2 u 6 000 000 M3 000 000 00.0 000 03 000 m mm» m fiMMMm mam m amm m mmm m mam . mmm m «M. . «mm m a». 5 mm» . mm. 1 WWW “mwm 7 xmfl 0m. lMlm I. 7W7 0W0 4M4 0M0 5mm...- “ 0W0 mmm mmm mmm mmm mm mmm mmm mmm mmm mmm ma mam mum mum um mum mum mmm mmm mum BMW” mwmmnn an. I: mag mm” HIGH? mummm m7. 58 1980. Twenty-one sites over 14 years generates a maximum of 811 site-years. Due to the fact that some of the sites (6 sites or 8 site-years) did not develop until midway through the study period, only 76 site-years actually existed. Seven sites (or 12 site-years) ceased operations during the study period and, therefore, only 61! "active" site-years occurred. W The results of the study were used to identify general patterns of development found in the vicinity of extractive sites. It is important to clarify what these patterns represent. Patterns were based on the change in land use proportions around each extractive site over distance, and over time. The analysis did not examine the cause of the observed development. The patterns of urban development observed can be divided into two categories; spatial and temporal. Three spatial patterns may occur. The first type is characterized by an increase in development with increased distance away from the pit. The second type exhibits a decrease in development with increased distance. The final type shows no distinguishable change in development with increased distance. The majority of the sand and gravel pits examined in this study are characterized by an increase in development with increased distance from the site. The term "distal" has been used in this report to describe this pattern. The general characteristics of the distal pattern are more residential and commercial lands and less vacant land with increased distance from the extraction site. The amount of residential land tends to maximize (to peak) within the nine distance rings 59 examined. To some extent, this also holds true for commercial development. Peaks for commercial and residential development do not necessarily coincide. The amount of commercial development is generally much less than residential development. Also, commercial development is not always present in rings closest to the pit. This makes it more Idifficult to distinguish patterns in commercial development. Of the 76 site-years examined, 65 (85.51) have distal patterns. These are indicated in Table h. Figure 15 illustrates a distal pattern, based on residential development in the vicinity of wu. Some of the extractive sites examined exhibited a decrease in development with increased distance. The term "proximal” has been used to describe this pattern. The general characteristics of this pattern are less residential and commercial land and more vacant land as the distance from the sand and gravel pit increases. Residential land use is greatest next to the extraction site. This may or may not hold true for commercial development. Of the 76 site-years studied, 8 (10.5!) fall into the proximal pattern. Table n indicates which sites have this development pattern. Figure 16 provides an example of a proximal pattern, based on residential development in the vicinity of H12. A few of the extractive sites studied do not appear to have any discernible change in development with increased distance from the site. The term "continual" has been used to describe this pattern. The continual pattern generally occurs in the earlier study years, when the amount of residential and commercial development was small. Of the 76 site-years studied, three (3.9” exhibit these characteristics. These pits are identified in Table h. 60 Table u. Spatial Development Patterns Pit 1957 196A 1972 1980 H2 C C D D vu D D D D H8 D D D D "10 P P D D H12 D P P (P) H13 --- D (P) (D) H15 --- D D D H16 D D D D AV17 --- --- D D AV20 --- D D P AV23 D C D D AV26 D D D D AV27 D D (D) (P) AV28 --- --- D (D) AV29 D D D (D) AV31 D D D D AV3h D D D D AV35 D D D D AV38 D (D) (D) (D) AV39 D D D D Avho --- D (D) (D) P - Proximal Pattern D - Distal Pattern C - Continual Pattern () - indicates site no longer active -- - indicates year prior to pit development 61 //7Z)///////////////////////, IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 5 x\\\\\\\\\\\\\\\‘ axxazxwzaxzaxawxawxa%Z%ZZ%Z:55 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII > .\\\\\\\\\\\\\\\\\‘ /////////////////////////// = IIIIIIIIIIIIIIIIIIII > .\\\\\\\\\\~ “—— //////////// — IIIIIII > 3. 7///////////, > \\\\\\I //////// > IIIIIIII - \\\\\\ //////////////////////, = Illlll - \\\V 7///////////////////. - I - .\\\' ////////, _ \\‘ 1 d» E» E: c: c: v 9) N " a 5 - '5 9 § 5 g a '6 I- .1 Distance Rings Example of a Distal Pattern-4m Figure 15. mm 6. 74 e 5 6 H w W 9 9 9 9 o 1. 1.. 4| 1I _ ZEE§M . w _ 1/ III/fl §§§ X 5—5:: =_====_==_=_=_============_==/==—=_===_=============== I IZI/llé/Iéggg _§§§§§§§§§§§§§§§h Pg. v §§§§ .\\\\\\\\\\\\\\\ H __===============__======_=================================_=====================_==__======_== V §§§§ \\\\\\\\\\\\\\\. I __=___==__==_=._=__====__======_=_=====_==========_======_===.==_===_=_=_=========_ =_====_======== V giggly/g; §§ \\\\\\\\\\\\\\\\s V =========_=_=====_========_==_================== =__=========_=_ 717////////////////g/§ V\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\V ______=__________=____=______=___==________=__________.____=____=.______._______==____== 5....______._.____.__.____ I / Z w. .m R e .\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\V\\\\\\\\\\\\\\\ n c ==_===_====_======___._...___=____=_.__a=\-=\_===—==—\=_==—==_======_=====_=_=_==========_ I m g a m §§ \\\\\\\\\\\\\\\\. I =====_===_======_=============_=__=_=__.=___.__===____=_=_=__==_===_======_____=_=========== =======_====== I _ _==_=================§§§E§ I = _ _ 347/1712! fig 1 Example of a Proximal Pattern—~W12 m w m. w w m m o a 1 .m e mew. m. emmmm m pa 1‘0 ar dil ab 1f 63 Patterns may also be identified on the basis of development trends over time. Three patterns can be distinguished, resulting from temporal changes in land use distribution in the vicinity of sand and gravel pits groups. The first pattern is characterized by an increase in development over time. It is described as an "increasing" pattern. The second type of pattern is the "decreasing" pattern. It exhibits a decrease in development over time. The last pattern is the "variable" pattern. Here development changes alternate between increasing and decreasing patterns. Table 5 shows the development patterns over time for the 21 study sites. Development increased in 18 (85.71) of the sites. Note that very few (3, or 111.31) variable patterns occur. Note also that no decreasing patterns are found. In all probability, the phenomenon of decreasing development over time should be relatively uncommon. Very few areas become less developed over time. When such a pattern does occur it is generally the result of inner-city abandonment, or the 'bust' of 'boom' activities. The occurrence of this pattern in this research project (as part of variable patterns) may therefore be misleading. It is probably a reflection of the method of analysis used, rather than any true, on ground, occurrence. The actual location of extractive operations on a particular site tends to migrate over time. Hence, the extractive sites for different years do not necessarily coincide. Therefore, the search areas for a particular sand and gravel pit, for different years, may differ. Any changes in land use proportions may partially reflect this shift in search areas. Decreases in development could thus be recorded if the extractive site, and therefore the search area, had moved 6” Table 5. Temporal Development Patterns Type Of Pit Pattern Development Comment H2 81 R wu sI R,C H8 I R H1O V drops between 1972-80 H12 31 R,C H13 I R,C H15 31 R H16 sI R,C AV17 sI R,C AV20 V R drops between 196u-72 AV23 I R,C AV26 sI R,C AV27 sI R,C AV28 I R,C AV29 sI R,C AV31 vsI R AV3h I R,C AV35 V R increases 1957-6h, variable 1964-80 AV38 51 R AV39 31 R AVhO I R,C I - Increasing Pattern s - strongly (modifier) D - Decreasing Pattern vs - very strongly (modifier) V - Variable Pattern R - Residential C - Commercial 65 slightly away from urbanization. As a result, misleading decreasing and/or variable development patterns over time appear to arise. Certain sites exhibit increased development over time within full view of the extractive operation. The pit H2 provides an excellent example of this. The site showed a strong increase in residential development, especially to the east of the site. The site itself is visually screened on all sides except the eastern boundary. Therefore, houses which developed to the east of the site did so despite the visual presence of the extractive operation. Rate of development may be a more accurate measure of change in land use proportion over time than temporal development patterns. Rate of development was determined from the change in land use proportion in the vicinity of each site over time. Three periods of development were examined: 1957-19611, 19611-1972, and 1972-1980. Hithin each time period the change in land use proportion, especially residential land use, was examined for each of the nine distance rings. The general trend of the nine rings was then compared to the average rate of development for the study area. Pour patterns emerged. Ring development rates may be greater than (>), equal to (s), or less than (0 that of the study area average. Occasionally different rings within a given time period show variable (V) patterns when compared to the area average. In variable patterns, the inner rings often show one pattern (i.e., less than the area average) while the outer rings exhibit the opposite pattern (i.e. , greater than the average). Figure 17 illustrates the different development rate patterns. The period 1957-19611 is characterized by rates of development less than (0 the study area average. The period 19611-1972 shows development rates 66 53:12.1 .=> mscil ....... .5 PE I I I x.. azulumoaeoaoaron no mean . up 9:8,: 8: .83 .38 .0 .52... 67 greater than (>) the area average. The last period, 1972-1980, has variable (V) development rates. The variability evident in the last time period results from the inner rings (I-III) having rates less than the study area average and the outer rings (IV-IX) having rates greater than the area average. Table 6 shows the rates of development for the extraction sites examined. Hhere variable patterns were identified, attempts were made to indicate any patterns relating to inner or outer rings. Many pits showed variable patterns. Often inner rings had development rates less than average while outer rings had rates greater than average. Of the twenty-one extractive sites, only eleven were active during all three periods of development. Of these, only two had consistent rates of development for all three periods. AV31 had development rates greater than the study area average for all three periods. H1O had development rates less than the study area average. The other nine active sites had development rates which varied for different time periods. Based on 21 extractive sites, and three periods of development, a maximum of 63 site intervals were generated. Six of the operations began operations sometime after 1957 and, therefore, only 55 site intervals actually existed. Of these 55 site intervals, 13 (23.65) had rates of development greater than the study area average. Pour (7.3!) had rates equal to the average. (Thus, 17 site intervals (30.9” had rates greater than or equal to the study area average.) Fifteen site intervals (27.3!) had rates of development less than the study area average. The remaining 23 (111.81) had variable patterns. (Of these 23, eight (311.81) resulted from inner rings less than average and outer rings greater than average, three (13.01) from reverse conditions, and 68 Table 6. Rate of Development Pit 1957-196A 1961-1972 1972-1980 H2 < > > wu < > v 1-3< u-9> H8 = v 1-6) v 7-9< w10 < < < H12 > < (>) w13 NA (>) (v) H15 NA = > H16 v 1-3< v v 1-2< u-9> 3-9> AV17 NA NA v AV20 NA v v AV23 < = < AV26 v v v 1-u< 5-9< AV27 < (V) (V) AV28 NA NA (<) AV29 < v 1-3< (>) u-9< AV31 > > > AV39 < = < AV35 v v 1-5> < 6-9< AV38 (y 1-36) (y 1-7) (>) n-9> 8-9< AV39 v 1-5< v v 1-2< 6-9> 3-9) Avuo NA (>) (<) ) Greater than study area average = Equal to study area average < Less than study area average V Variable () indicates pattern when site no longer active NA indicates period prior to pit development 69 twelve (52.31) showed no distinguishable pattern based on inner and outer rings.) .Snness_2£_1nflnenee The limits of the development patterns occurring in the vicinity of extractive sites were defined in hopes of delineating the sphere of influence of extractive Operations on urban development. Residential development was used as the indicator of the sphere of influence. Both spatial and temporal patterns of development were addressed. As mentioned in the previous section spatial patterns of development are characterized by distinct changes in land use distribution with increased distance from the site of extraction. Both distal and proximal patterns exist. For both patterns the sphere of influence can be defined. The limit of the sphere of influence was indicated by a change in direction of the development pattern. The mid-point of the ring preceding the change defined the boundary of the sphere. For distal patterns this was where residential development peaked (local maximum). For proximal patterns it was the valley (local minimum) prior to which development started increasing. Overall trends in development were used. Investigator Judgment was used to smooth out erratics on the graphs. Spheres of influence were determined for each study year. Table 7 lists these for each site. This same information is graphically presented in Figure 18. Symbols are used to differentiate between spheres of influence resulting from proximal and distal patterns. The majority of the sites examined had distal spheres of influence. This 70 Table 7. Sphere of Influence 1957 196" 1972 1980 H2 8767C h32?C 288 D 288 D H8 1128 D 1128 D 1128 D 1128 D H8 876 D 876 D 876 D 876 D H10 180 P n32 P 108 D 108 D w12 108 D A32 P 288 P (1128 P) H13 --- 62h D (180 P (288 D) H15 --- 138 D 1380 D 1380 D H16 876 D 876 D 876 D 876 D AV17 --- --- 832 D 876 D AV20 --- 288 D 180 D 628 P AV23 628 D 832?C 288 D 180 D AV26 288 D 288 D 108 D 628 D AV27 628 D 932 D (628 D (288 P) AV28 --- --- 108 D (108 D) AV29 1380 D 1128 D 1128 D 1128 D AV31 832 D 932 D 876 D 180 D AV38 1380 D 1380 D 1380 D 1380 D AV35 876 D 1128 D 108 D 180 D AV38 1128 D (1128 D) (629 D) (108 D) AV39 628 D 624 D 624 D 1380 D AVRO --- 180 D (180 D) (288 D) P - Proximal Pattern D - Distal Pattern C - Continual Pattern 7 - questionable due to lack of development () - indicates site no longer active --- - indicates year prior to pit development 71 ooeesaueH uo enema» .wp oasuum Ozw VVV V NVVVMN mmmmmmammmuummmmmmwmm 0:» ezuxvcna 8.8.2. o:=.msxzm panama _e:§§:a .X§R£BC.A .22.... 03% 8.08 0.00.00... .00... flr--* ~* V*'**~'~* ~*-***'*~v .0...- M0981 —-—aeI ........mt —I.961 72 was expected, as most sites exhibited distal patterns. Note that when both types of spheres were identified for a particular active site the maximum sphere of influence resulting from a distal pattern was relatively small (H10=108 m; H12=108 m; AV20=288 m). A number of patterns emerge for those pits which ceased operations during the study year. For most sites, the sphere of influence during active years resulted from distal development patterns (H13, AV27, AV28, AV29, AV38, and AVllo). For four of these sites, distal spheres of influence remained after operations ceased (AV28, AV29, AV38, and AVAO). But, the size of the sphere decreased with time. At one site (AV27) the sphere after operations initially ceased was due to distal patterns, but eventually switched to one resulting from a proximal pattern. Only H13 differed greatly. During its active year, H13 had a distal sphere of influence. The first study year after operations ceased showed a proximal sphere. The following study year showed a distal sphere. This may be a result of the location of H13 and its proximity to Pontiac Lake. In the years up to and including 1972, a great deal of residential development occurred north of H13, along the shoreline of Pontiac Lake. The proximal sphere for H13 in 1972 reflected this. Between 1972 and 1980 there was little room for increased residential development around Pontiac Lake. At the same time both residential and commercial development were occurring further away, to the south of H13. The end result of this was a distal sphere in 1980. Thus, the change from proximal to distal sphere related to development elsewhere, not to pit activity. A similar pattern was observed for H10, situated on the apposite side (north of) Pontiac Lake. Although H1O was active throughout the 73 study period, it too changed from a proximal sphere to a distal sphere. In the case of H10 this was the result of a shift in the location of lakeshore development. The pit is situated on the north side of Gale Road. To the south, the north shore of Pontiac lake curves away from the road, allowing residential development to occur between the lake and Gale Road. This was where earliest development occurred. To the east of this area, the lake abutts on the road. Development is therefore restricted to the area north of Gale Road. This area was less desirable for residential development and hence developed later. This was reflected in the change from proximal to distal sphere of influence. Average values for spheres of influence were calculated. For distal patterns the mean value was 686 m, based on 68 active and non-active site-years. The mean value for active site-years only (of which there were 59) was 715 m. The Student's t Distribution Test, using a 95% confidence level, showed no statistically significant difference between the two values. For proximal patterns a mean value of 111111 m was calculated based on eight site-years (both active and non-active). Using just active site-years (n=5) the mean value was 391 m. There was no statistically significant difference between the two values. We Attempts were made to relate certain site characteristics to the development patterns and spheres of influence identified. Three characteristics were examined: location, size, and phase of pit development. Sites were grouped as being urban or rural (location); large or small (size); and increasing or decreasing in size (phase of 7n pit development). For each group the average (mean) sphere of influence was calculated. The average sphere of influence for the groups describing each characteristic were then compared. Site locations were classified as urban or rural, depending on the relative amounts of development in their surrounding area. Total acreage of current disturbance was used to define site size for an individual or group of pits. Small sites were those where total area was less than 50 acres. Large sites were those where total area was greater than 50 acres. Size for one site could vary for different years. Phase of pit development related to changes in pit size for the periods 1957-196A, 196n-1972, and 1972-1980. Increasing sites exhibited an increase of more than 151 within the particular time period. Decreasing sites showed a decrease of more than 151. Those sites which changed by less than 15% in either direction were considered constant. Of the 21 sites examined, 11 (52.4!) were urban and 10 (h7.6$) rural. Ten sites (117.61) were small throughout their operating period, 3 (111.31) were large, and 8 (38.11) varied between small and large. The eight pits represented 30 individual pit-years. (Of these, 16 (53.3” were small and 1h (46.7!) were large.) forty-three phases of active pit development were identified. Twenty-eight (65.1%) were increasing phases, 12 (27.111) were decreasing phases, and 3 (7.0!) were constant. Table 8 details the characteristics for each site. Using the information in Table 8 the sites were categorized according to characteristics. Only those sites with distal spheres of influence were included. Proximal spheres of influence were not included because they result from a different type of development pattern. These two development patterns are distinct groups. Due to 75 Table 8: Pit Characteristics W2 W4 W8 W10 W12 W _i 3 W15 W16 AV17 AV20 AV23 AV26 AV27 AV28 AV29 AV31 AV34 AV35 AV38 AV39 AVUO Location R R R R U R U U R R R U U U U U R R U U U Size 1957 S L S S S —— -- S -- —— L S —- S S S S S L -- 1964 L L S S S S S S —— S L S S —— S L S L -— S —— 1972 L L S S S —- S S L L L S -— S L S S L ~— S S 1980 L L L S —- —- S S L L L S -- —- —— S L L -— L —- Phase of Pit Development 1957-1964 I D D I I -— -— I -- —- I I D -- I I I I -- D -- 1964-1972 I D D I I -- I D -- I I I -— -- I D I I -— I —— 1972-1980 C I I C —- -- I I D C I D -— —— —- D I D —- I -- Location Size Phase of Pit Development R - Rural S - Small I - Increase U - Urban L — Large D — Decreasing -~ - indicates pit not active C — Constant 76 the low number of proximal spheres of influence, separate statistical analysis was not possible for sites having proximal development patterns. The following sites were therefore excluded from all statistical analysis: H10 (1957 and 19611); H12 (19611, 1972, and 1980); H13 (1972); AV20 (1980); and AV27 (1980). The sites included in each group are listed in Table 9. Note that for size and for phase of pit development, groups were sub-divided by year. Figures 19, 20, and 21 are graphical representations of the sphere of influence for each site grouped according to location, size, and phase of pit development respectively. One useful method of analysis is to determine the central tendency and variability of a group of data. For the site groups shown in Table 9 the measurements of sphere of influence were used to calculate group mode, median, mean, and standard deviation (Table 10). These values were then used to examine the distribution and variability of spheres of influence within each group of similar sites. The calculated values generally indicated a wide range of spheres of influence within each group. The values showed no tendency to cluster about a central value. Many of the groups were multi-modal (i.e., more than one value for sphere of influence occurred with equally high frequency). Hhere groups were uni-modal (i.e., only one value Occurred with highest frequency), the actual frequency of the value was relatively low. This was probably due to the small group sizes. No consistent patterns were noted when group mode, median, and mean were Compared. 77 Table 9. Groups Based on Site Characteristics * W2 wu W8 W10 W12 W13 W15 W16 AV17 AV20 AV23 AV26 AV27 AV28 AV29 AV31 AVBH AV35 AV38 AV39 AVUO NUMBER Location Rural X X X X X X X X X X Urban X X X X X X X X X X X Size Small 1957 X X 196M X 1972 X 1980 Large 1957 196M X 1972 X 1980 X Phase ><><><><1 ><>< >< ><>< ><><><>< >< ><><><>< >< >< >< >< >4><><>< >< >< ><><><>< >< >< Increasing 1957-196A X 196u-1972 X X X X X X X X X X X 1972-1980 X X X X X X X Decreasing 1957-1964 196u-1972 X X X X 1972-1980 X X X X Constant 1972-1980 X X X >< >< >< X N >< >< >< N N N >< >< * All sites with positive spheres are excluded. 78 MIRA 3:95 eowusooquuooeosaeH no 9.23m 3.9.5: v . mmmmmm e . mp 0.2.3.: .22.... 02m 79 '*~'*'096L ---zas: ........'96t ---:seI eeeeeeeeee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeet eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeei eeeeeeeeeeeeeeeeeeeeeee eeeeeeeeeeeeeeed 0.0.0....OIO...OOOOOOOIOCOOOOOIOOOO00......000..... OOOOOOCOOOOOOOO0.0I.00...00.0.0.0...00000.0.0.0...OOOOOOOOOOOOOOOOOOOOCOOO .OOOOOOOOCCIOOOOOOOOOOOOOOOOOOOOOOOI 00.....0.0..0.00.0000...OOOOCOOOOOOOOOOOOOOOOOO tux» 1uur 624- 432- 288- oo- oo- 36‘ 04 Fawn Sfle ineuws) ana- Large Sites SnwulSfles Sphere of Influence-Size Groups Figure 20. 38533.69 3.. no canmiiooegagn uo season .3 one»: 08.... 58960 8!... 058280 3!... 9.33.»... 80 AAAA-A .O... .8... eeeeeee 0000 .00 eeee so. see. _ 0000000 a e... eee O. O. M see. . eee sense 3 A .... v . , .H. ..... so oooooo . n... .W .09 . eeoo .. eeeeeeee eeee M. eeeeeeee A .... A 0000 case J 0 see. A. O... A .... A 0.00 .... .... .... ... ... ... ... see 0 mm “m. as. .vao m I. , . 8%... 89 «a. 82 m :m mum 2 s s A. u .8: «S. 82 Ba. I H .80.. 81 Table 10. Site Group Statistics Standard n Mode Median Mean Deviation Location Rural-all 32 876 628 678.0 838.0 -active 31 876 750 690.6 839.3 Urban-all 36 628 628 681.3 837.5 -active 28 tri-modal 628 726.8 837.7 Size Small 1957 11 876 876 808.0 813.6 1968 11 multi-modal 628 738.2 830.2 1972 9 bi-modal 876 708.0 509.3 1980 5 multi-modal 628 633.6 523.9 Large 1957 3 628 628 792.0 291.0 1968 5 832 832 710.8 381.2 1972 7 bi-modal 288 507.8 835.7 1980 8 tri-modal 876 786.0 510.1 Phase Increasing 1957-1868 8 832 658 762.0 816.5 1968-1972 10 108 288 559.2 535.1 1972-1980 7 1380 1128 1028.6 837.2 Decreasing 1957-1968 8 multi-modal 750 765.0 302.7 1968-1972 8 876 876 939.0 126.0 1972-1980 8 180 803 865.0 388.8 Constant 1957-1968 0 ND ND ND ND. 1975-1972 0 ND ND ND ND 1972-1980 3 multi-modal 288 380.0 261.9 ND - No Data 82 The different groups for each characteristic were then compared. The Student's t Distribution Test was used to compare mean values for sphere of influence. The hypotheses tested were: 1'10: U1 = 112 i.e., that there is no statistically significant difference in means. 81‘ “I a! “2 i.e. , that there is a statistically significant difference in means. The rejection region used was: For a probability of<1=0.05 of a type 1 error (i.e., rejecting the null hypothesis when it is true) and degrees of freedom df=n1+n2-2, reject no if tc>ta/2. In other words, no was accepted unless the calculated value for t (to) '88 SPOEtOP than the value Of t0/2 obtained from the table of percentage points of the t-distribution using 01:0.05 (95.01 confidence level) and GOSPGGB or freedom df=h1+n2-2. Eleven comparisons were done. The results are shown in Table 11. Only one comparison resulted in rejecting Ho' The category involved was phase of pit development and the comparison was between spheres of influence for sites during increasing phases and constant phases for the period 1972-1980. The group containing sites with constant phases was the smallest group examined, with only three sites included. The standard deviation calculated was approximately 771 of the mean value determined. For this reason, the results of the comparison are questionable. 83 Table 11. Statistical Comparison of Pit Groups Comparison 'df tc ta/z e Results Location Rural vs Urban All Pits 66 .005 1.960 accept H Active Only 57 .310 1.960 accept Ho Size Small vs Large 1957 12 .087 2.179 accept no 1968 18 .106 2.185 accept Ho 1972 18 .818 2.185 accept no 1980 11 .519 2.201 accept Ho Phase of Pit Development Increasing vs Decreasing 1957-1968 10 .013 2.228 accept no 1968-1972 12 1.373 2.179 accept no 1972-1980 9 2.200 2.262 accept Ho Increasing vs Constant 1972-1980 8 2.891 2.306 reject Ho Decreasing vs Constant 1972-1980 5 .521 2.571 accept Ho 'From Ott, Lyman. 1977. W- Duxbury Press, North Scituate, Mass. 6599. Based on a = 0.05 W Table 2; Percentage points of the t distribution. 88 Grouping of sites on the basis of identifiable characteristics (location, size, and phase of pit development) did not result in statistically significant differences in mean value for sphere of influence. Therefore, sites of similar character do not have similar impacts on development . CHAPTER V SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS Su-ary Thirty-nine sand and gravel extraction pits in Oakland County, Michigan, were examined in this study. These were grouped into twenty-one sites for analysis purposes as discussed in Chapter IV. Land use changes in the vicinity of these sites were determined for the period 1957 to 1980. The microcomputer based Earth Resources Data and Analysis System 800 (ERDAS 800) was used to analyze this information. The results obtained were then interpreted focusing on three points of interest: (1) patterns of development identified in the vicinity of extraction sites; (2) sphere of influence of extractive operations on surrounding development; and (3) relationship between certain pit characteristics and identified development patterns and spheres of influence. Two aspects of development patterns were examined: those resulting from changes in land use proportions with increased distance from the extraction site (spatial patterns); and those resulting from changes in land use proportion over time (temporal patterns). For spatial patterns of development, three patterns were identified: (1) proximal patterns, characterized by decreased urban development with increased distance from the site; (2) distal patterns, exhibiting increased development with increased distance from the site; 85 86 and (3) continual patterns, showing no discernable change in development levels with increased distance from the site. The majority of the sites examined (85.51) had distal patterns. Temporal patterns were divided into three patterns. The first, increasing patterns, showed increased amounts of development over time. Decreasing patterns were characterized by decreased amounts of development over time. The third pattern, variable, fluctuated between increasing and decreasing patterns. The majority of the sites (85.71) had increasing patterns. It is probable that decreasing, and therefore variable, patterns arose as a result of the method of analysis used, and are not true patterns. A more accurate reflection of change in land use proportion over time (temporal development patterns) was that of rate of development. For each time period (1957-1968, 1968-1972, 1972-1980) the development rate for each site was compared to that for the study area average. The nine distance rings around each site were examined. Each time period for each site was rated as having a development rate greater than (>) , equal to (z), or less than (<) that of the study area. Those sites which exhibited variable (V) development rates among distance rings were also noted. 0f the twenty-one sites examined, most did not have consistent development patterns for all three time periods. Only 27.31 of the site intervals examined had development rates less than the study area average. Almost one-third of the sites (30.91) had rates greater than or equal to the area average, while 81.81 exhibited variable patterns. Spheres of influence were delineated by identifying the limits of the development patterns. Residential development was used as the 87 indicator. Two classes of spheres were identified: those based on spatial patterns of development, and those based on temporal patterns. Spatial spheres of influence were classified as being proximal or distal, based on the pattern of development. For each site the limit of the sphere of influence for each study year was determined. The mean value for the sphere of influence for proximal spheres was 888 meters, based on eight site-years. The mean value for distal spheres was 686 meters, based on 68 site-years. Attempts to relate certain extractive site characteristics (location, size, and phase of pit development) with the development patterns and spheres of influence identified were unsuccessful. Grouping of sites on the basis of these characteristics did not result in statistically significant differences in mean values for sphere of influence. Hithin each group, values for sphere of influence showed no noticeable tendency to cluster around a single value. Conclusions The results of this study have definite significance to the sand and gravel extractive industry and the communities in which it operates. The validity of the widespread public belief that the presence of a sand and gravel pit discourages urban development was not supported by this research. The investigator therefore concluded that this belief is questionable, if not false. The general pattern of development observed in the vicinity of extractive sites was one of increased development with distance from the site. This pattern existed for an average distance of 686 meters (0.83 miles). Beyond this point development trends tended to be similiar to 88 those of the surrounding area. This does not automatically mean that the presence of an extractive operation retards urban development. The majority of the sites examined were located at the outer fringes of urban development. Initially, most of these extractive operations were situated some distance from the urban area. But, the outward spread of urbanization resulted in a transformation of the land use in the vicinity of extractive sites. Hith time, the area surrounding most pits shifted from vacant and agricultural land to residential and commercial land use. The shift in land use over time was probably reflected in the distal pattern of development. For many sites, the increased amount of development with distance from the site (distal pattern) probably resulted from urban growth, rather than any influence of the extractive operation. Some of the sites examined in this study exhibited a decreased amount of development with distance from the site (proximal patterns). To conclude from this research that these sites actually attracted urban development would be misleading. Development in these areas was probably influenced to a greater extent by other factors. The idea that extractive operations have a neutral impact on development must therefore be considered. This is certainly supported by development trends in the vicinity of extractive sites over time. It is important to note that in most cases development in the vicinity of the extractive sites increased with time. In certain cases (i.e. , H2) this occurred within full view of the extractive operation. This would seem to indicate that the presence of the extractive operation did not detract from future residential development. As well, less than one-third of the site intervals examined exhibited development rates 89 less than the average rate for the study area. Such development trends support the idea that sand and gravel extractive sites exert no influence, or a neutral influence, on surrounding development. From this, it can be concluded that the presence of an extractive operation is not necessarily a dominant factor influencing urban development. The development patterns observed in the vicinity of extractive operations result from a number of factors, i.e., natural physical conditions of the site (soil, hydrology, etc.) and man-made conditions (availability of public utilities and services, property acquisition, etc.). Although sand and gravel pits may exert some influence on patterns of urban development, the amount of influence varies from site to site. Attempts to relate certain site characteristics to the observed patterns of development and spheres of influence were unsuccessful. Sites of similiar location, size, or phase of pit development did not have similiar impacts on development. The major conclusion of this study is that, on a generalized basis, the presence of sand and gravel extraction does not discourage development. The generalizations held by much of the public pertaining to the negative influence of sand and gravel operations on urban development were not substantiated by the present research. As well, this study found that the presence of an extractive operation is not necessarily a dominant factor controlling surrounding land use. As a result, the possibility of extractive sites having a neutral influence on urban development must be considered. The conclusions of this study suggests that no generalization can be drawn about the potential influence of a planned extractive operation on urban development surrounding it. Each site should be examined 9O separately. For any proposed extractive operation, the local conditions must be fully examined prior to determination of potential influence on urban development. Generalizations based on existing sites in other localities may not be correct. This concept of site individuality should be understood by planners of potential extractive operations, and by the communities in which the proposed site is situated. Recc-emdatioms for Future Research Prior to any discussion of potential research, one key fact needs to be mentioned. This research project concluded that extractive sites exert variable influences on urban development depending on the site. As a result, members of the sand and gravel industry have no reason to fear the results of future research. In fact, future research may indicate that some of the negative impacts of sand and gravel operations are over-estimated. This does not mean that further research is not needed. On the contrary, additional research is necessary to provide solid data and to improve public opinion concerning the sand and gravel industry. Ccmunity organizations should also be willing to carry out research. This is necessary if they are to increase their ability to provide relevant information regarding planning of extractive operations. Future research should examine a number of questions. Hhat quantitative influences do sand and gravel operations exert on development patterns? Extraction sites are just one of the many factors which might influence the siting of development. The relative weights of each of these factors, including sand and gravel extraction, should be determined. Also, any shift in significance of factors with changes 91 in distance or time should be examined. Hhat factors overshadow the presence of a sand and gravel operation? For example, would the presence of a picturesque lake exert more influence on development than a nearby extractive operation? Hhat about zoning or property ownership? How does the character of the post-mined land affect development? If an extractive operation produces a lake as one of its by-products, does residential development occur in anticipation of the lake's presence? An on-site examination of fewer pits might provide insight as to more specific patterns of development. For example, does development relate to topography? How does site visibility influence development? Hhat influence do truck routes exert? The qualitative influences of sand and gravel operations on urban development might also be examined. Hhat types of development are found near extraction sites? Does residential, commercial, industrial, or some other type of development dominate? Hhat is the quality of that development? For example, is residential development in the area dominated by large, high-value homes, by moderate-value homes, or by trailer parks? A second area of possible examination involves operational procedures. How much control does an operator have over development patterns? Are patterns influenced by certain individual phases of the extractive operation, or by the entire process? Do surrounding development patterns vary between wet operations and dry operations? Finally, what are the economic impacts of sand and gravel pits? A detailed examination of this is long overdue. Are property values in the surrounding area effected? Hhat about increased revenue into the community resulting from direct company spending and indirect spending 92 by company employees. Are new jobs created, and if so, how many? These types of questions are best examined on a small scale, perhaps looking at one or two individual sites. A historical approach might be necessary to detail changes in property values before, during, and after extractive operations. These are just a few examples of potential areas for examination. There is no limit to the amount or scope of future research. Much work still needs to be done, and should be done. APPENDIX APPENDIX LIST OF AIRPHOTOS W 1957 1968 1972 1980 XR-1P-178 XR-2P-63 to 73 XR-ZP-116 to 119 XR-ZP-189 to 158 XR-ZEE—115 to 123 XR-ZEE-151 to 159 XR-ZEE-187 to 189 XR-ZEE-223 XR-1MH-69 to 71 XR-IMM-83 to 87 XR-1MM—128 Semcog 80-230-16-8 to 11 Semcog 80-230-17-9 to 15 Semcog 80-230-18-10 to 12 Semcog 80-230-19-11 to 13 W 1957 1968 XR-1P-17 to 25 XR-1P-87 to 99 XR-1P-187 to 195 XR-ZP-IS to 23 XR-ZP-61 to 65 XR-ZP-191 to 199 XR-ZP-ZIS XR-3EE-18 XR-BEE-81 to 89 XR-3EE—63 to 71 XR-3EE-97 to 99 XR-BEE—IZS to 127 XR-BEE-ISB XR-BEE-177 to 183 XR-3EE-195 to 201 XR-BEE-ZOS to 211 93 1972 1980 98 XR-1MH-181 to 185 XR-1MM-188 to 190 XR-1MM-205 to 209 Semcog 80-230-21-9 to 11 Semcog 80-230-22-9 to 15 Semcog 80-230-23-9 to 15 Semcog 80-230-28-9 to 15 Semcog 80-230-25-9 to 15 REFERENCES REFERENCES Banks, P. T., R. E. Nickel, andD. A. Blome. 1981. W e e a e a e ° ' : 1 1; e ; e g 1 e 1 e m Contract No. J0199052. US Bureau of Mines, Hashington, D.C. 183 p. Bates, R. L. 1969. 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