Landscape Analysis for Planning in Mountain Community
Mart i n
Prepared for Planning Studio 3 as an Exit Requirement For a Masters Degree of Urban and Regional Planning/ Community Development From The University Of Colorado at Denver, College of Environmental Design. July, 1981
TABLE OF CONTENTS
The Problem of Mountain Planning Research Methodology Scope/Limitations of this study
2 THE ELDORADO SPRINGS PROJECT AND THE COMMUNITY PLANNING PROCESS
The Community Development Approach The Community Planning Process The Planning Problem
3 LANDSCAPE ANALYSIS PRINCIPLES AND THEIR RELEVANCE TO
THE ELDORADO SPRINGS PROJECT
The Purpose of Landscape Analysis Landscape Analysis Principles The Comprehensive Approach
4 AN ENVIRONMENTAL ANALYSIS OF ELDORADO SPRINGS USING THE MCHARG METHOD
The McHarg Method
How The McHarg Method Works
Environmental Factors of Eldorado Springs slope
' fragmenting bedrock blockglide rockfall fragile shale soil creep slump failure swelling soils alluvial erosion river erosiom bank
aggravating circumstances of hazards ecosystem impacts
Problems with the McHarg Method
5 LAND LANDSCAPE ANALYSIS FOR MOUNTAIN COMMUNITIES
How the New Method Works The Method's applicability to similar situations
The purpose of this study is to present a method of determining land suitability for small mountain communities based on environmental factors. The method was developed during a comprehensive planning project in Eldorado Springs, Colorado. This study will focus on a small segment of the overall project. 'A discussion of the problems encountered in Eldorado Springs, the Community Planning Process, and the Principles of Landscape Analysis will demonstrate why a "new" method was needed.
During the alternative analysis phase of the Eldorado Springs Project a major problem was discovered and resolved by producing a land suitability map. The problem was to find a method to delineate the amount of land environmentally suitable for town development within the study area. The McHarg method of overlaying maps of constraints to development to reveal areas which have serious limitations was rejected because it had limited capacities to achieve the objectives of our situation. The new method, which is a modification of the McHarg method, was designed for the needs of our situation.
Hopefully, our situation was not unusual. In our case, the method was an aid in plan making.
It was tailored to the small, complicated environment of a mountain canyon community. Our priority was only that it fit into the Community Planning Process.
THE PROBLEM OF MOUNTAIN PLANNING
Colorado's identity is inseparably linked to the Rocky Mountains. They have been a home for Indian gods, obstacles to movement, places for refuge, and an endless source of inspiration.
They occupy a special place in Colorado's history. Today these mountains are under increased pressure for recreational, mineral and town development. With greater use of the mountains the possibilities for environmental degradation will increase dramatically, and we take a risk of losing part of our identity. If the ultimate goal of land-use planning is the creation of an environment which provides the "optimum quality of life", the planner must involve himself in a process which balances these environmental and cultural factors.
The growth occurring in the mountains is no more or less than the growth affecting the rest of the state. However, the basic topographic characteristics of the mountains, those of high altitude and slope, are likely to exaggerate any type of disturbance, no matter how sensitive.
In effect, soil degradation, infertility and abuse of grazing land will have a negative consequence anywhere. On mountain slopes, the effects will turn into a disaster. (Ivers, p. 13).
Geomorphologists often use the term "high energy environment" when discussing mountain regions.
A high energy environment is defined as an area possessing high relief, where processes natural, man-made, or man-augmented are rapid. In other words, these processes are influenced by a combination of elevation, slope angle and gravity. (Ivers, 1974, p. 12)
"The problem...of the world's mountains can be stated very simply. In an already high energy environment, rapidly accelerating human pressures over the last 50 years are exponentially augmenting massive and rapid transfer of large volumes of material down-slope. Thus we have a human element imposed on a natural system. We cannot begin to quantify the human element and thereafter move on to develop long-range planning and other counter-measures without understanding more clearly the natural system, or the man-nature interacting system that existed prior to the middle of this century. Nor can we call a halt to the devastating human process, even if governments and planners possessed absolute dictatorial powers. Nor can we delay the necessary decision making until all the research needed has been completed." (Ivers, 1974, p. 12)
Mountain land resources are useful and finite. Their scarcity and vulnerability require that the planning process define the objectives of their use and allocate them in accordance with those objectives. This must be tempered with the fact that if an individual wants to own a mountain home or business and has the capital to do so, it is his right. Good planning hopefully balances the rights of individuals with those of the overall community.
Planning has two general phases: plan development and plan implementation. This study focuses on the first phase. It is felt that the more strongly a plan is rooted in good planning principles, the easier it will be to implement. The methodologies used in plan development, in other words, should be directly tied to the plan's implementation.
It is also felt that to have a plan that works, the community needs to be knowledgeable about how the planning process works. This way, the citizens can involve themselves at all stages. The reason for this should be obvious: It is the people who are imposing constraints upon themselves. Understanding the total process is important because planning is essentially a political process. In this country, it is a democratic political process.
Organization of Study
This study will follow a research organization which involves five sequential steps: 1) inventory of base information and problem identification; 2) investigation of standard methods used to solve similar problems; 4) summarization of conclusions; 5) documentation of results (see chart p. 5 ).
Much of the information contained in this study was gathered during the fall and spring semesters of the 1979-80 academic year. The information was re-checked arid the changes reflected here.
The project was conducted with a community development approach to planning which is described in Chapter 2. Data borrowed for use in this study came from the following sources:
1) a household survey; 2) a detailed mapping study of environmental and social factors in the Eldorado Springs Area; 3) a literature search of information pertinent to the Eldorado Springs Area; 4) Interviews with professionals in related fields.
In the fall of 1979 a household survey was distributed to the residents of Eldorado Springs. The survey was a product of many hours of work by the residents and th^ University of Colorado team. Original ideas for the survey questions came from a "brainstorming" session with residents. From there, ideas were grouped according
to topic and were transferred into a viable question. Every two weeks a meeting was held with interested residents in which the questions were critiqued. In addition, input was obtained from survey methodologists, sociologists and other outside experts. The results were computer tabulated and areas tabulated and then analyzed.1
The mapping study was carried out at the same time by a different student team. This study mapped environmental social and land use information important to the community. It also compiled and explored the planning issues identified through the survey and meetings with the steering committee. Information for this project was gathered from published sources from Federal and state governments. Much information was also obtained from county sources. The ultimate goal of the mapping and survey projects was to gather as much information as possible within the semester time period so as to get a "complete picture"of the social and physical environmental conditions of the Eldorado Springs area.
The second stage of the project was the analysis stage of the project and the stage in which this study will focus. This study examined the many possible ways Eldorado Springs could develop in the future. Several scenarios of the future were generated. The scenarios were based on a different combination of utility, environmental and legal possibilities. The method of data search involved in this phase was in the form of design workshops. From discussions with steering committee members, residents' ideas
were put into graphic form right there and then.
The residents were allowed to become very actively involved in the process. This allowed participants to elaborate on their ideas and revise them.
It also allowed for compromise and consensus within the residents' community itself and between the residents and the design team to take place.
New information contained in this document came from a literature review into the fields of landscape analysis, community development, small town planning, environmental planning, ecology of Boulder County and cartographic analysis. Because cartographic analysis is not common to most planning studies and this type of analysis is key to this study, the principles of the field will be discussed in the following paragraphs.
Cartography is a technique fundamentally concerned with reducing the spatial characteristics of large areas a portion of the earth... to a form that makes them more observable. (Robinson, 1969,p.2)
If well made, a map can be an instrument for researching, calculating, displaying and analyzing the interrelationship of things in space.
Because of the constraints that result from the ever present scale reduction and the need for clarity and legibility, the geographical data cannot be shown as they appear in reality but instead must be symbolized. This is one of the major ways in which a map differs from an air photograph.
The cartographer must generalize his map for the purpose of communications to the reader (it may be himself) geographical concepts. In order to portray the important aspects of reality, various manipulations of the data to be mapped are necessary. These may be grouped into four major categories which have been termed the elements of cartographic generalization. (Robinson,1969,p.52)
1) Simplification; that is, the selection of characteristics of the data, possibly its geographical modification and the elimination of detail.
2) Symbolization; that is, the graphic summarizing and coding of essential comparative significance and relative position.
3) Classification; that is, the ordering of scaling and grouping of geographical phenomenon.
4) Induction; that is, the application in cartography of the logical process of inference.
These fundamental and complex processes are all consciously accomplished by the cartographer in the practice of map making, but each map provides a different set of requirements. The "mix" of the elements of generalization as are combined vary from map to map depending on the purpose, scale and the graphic limits, that is the capability of the systems employed for the communication. (Robinson, 1969, p.53) The point is that the competent cartographer has control of scale, generalization and the "visual" effect of his maps, all of which are directed toward the purpose of communicating the ideas he wants to express.
The Case Study
The case study was used for several reasons but primarily because it was a clear case in which to test the various theories developed in this document. The situation of a small mountain community allowed us to examine the methods within a more holistic context because of its relatively small geographical area and population.
In other words, the simplicities of a small scale situation allowed a detailed consideration of both social and environmental contexts.
SCOPE/LIMITATIONS OF THIS STUDY
The scope of this study is necessarily very broad. The number of environmental issues involved with mountain planning require a comprehensive approach. Also, the factors of high slope and altitude, the prime determinants of the mountain environment, are common to all mountain towns. These factors make the problems discussed in this document applicable to most mountain communities.
The approach therefore is an outline of the major issues. The discussion of the problems and the mitigation methods presented are not by any means definitive. Complete works on any one of these issues can usually be found. It is hoped that this study can be used in the general way it is intended causing reflection on the problems and issues presented and encouraging further study. If this happens, the basic purpose of this endeavor will be accomplished.
This study will also remain limited to small scale development. The effects of large scale intensive development, such as commercial mining to the physical and human environment in the Colorado Rockies are beyond the scope of this work.
During the literature search required for this study, it was found that no land assessment method existed that dealt specifically with
During the literature search required for this study, it was found that no land assessment method existed that dealt specifically with either small areas or with micro-ecosystems (18 methods were investigated). By no means did the researcher include all of the approaches in existence or for that matter all approaches of which he was aware. Much of the information on existing Landscape Analysis methods was obtained from a study by a team from the Harvard University Department of Landscape Architecture Research Office. The study analyzed a selection of 18 "state-of-the-art" Landscape analysis methods. The comparative base of the methods was a computer compatible data base on the southwestern sector of the Boston metropolitan area. It is therefore assumed that small scale methodologies are still in their pioneering stages. The justification for research here is that it attempts to correct the shortcomings in the field by devising a more satisfactory methodology.
XVKNTOWV OF Atl WFOAMATIOW
DtFIHlTlOH OF PROBLEM
imr*tT*OATiow O' CO*J"'T*
LLCT or ]J
If infOKTlOH ,
Ij *Â¥** OF ,
M UMDtC*n l
or itrt or
1 MTNOO PO
THE ELDORADO SPRINGS PROJECT AND THE COMMUNITY PLANNING PROCESS
The method of determining land suitability for mountain communities was designed to meet the needs of the Eldorado Springs project. It is necessary to describe the circumstances under which the project was developed in order to fully understand the problems it intended to address. The objective of this chapter will be to discuss the problems encountered in Eldorado Springs and the Community Planning Process.
This will demonstrate why the land suitability map was needed and how it fits into the overall planning process.
The Community of Eldorado Springs is a former resort that was subdivided around the turn of the 20th century. It is located about 10 miles southwest of Boulder at the north mouth of South Boulder Canyon. Because it is beginning to feel pressure from developers the community requested assistance from the Center for Community Development and Design to develop a comprehensive plan.
The major problems that planning could address in Eldorado Springs can be divided into two main categories: growth pressures due to its location and its environmental constraints to development.
The location of Eldorado Springs makes it a prime area for growth. It is located on the front range of the Rocky Mountains, which is experiencing significant development pressures. The natural beauty of the canyon makes the area attractive to developers and homeowners. The nearness of Boulder and Denver allows the conveniences of both city and mountain living to would-be residents of Eldorado Springs.
Eldorado Spring's nearness to Boulder makes it susceptible to growth for another reason. Boulder County's land use policies strictly limit the amount of new subdivision which can take place in the county. The hillsides around Eldorado Springs have already been subdivided. This makes Eldorado Springs one of the few places in outlying Boulder County where development can occur. As long as Boulder remains a desirable place to live, the available land in Eldorado Springs will be under development pressure.
The community is also located in a canyon between the foothills and the hogbacks of the Rocky Mountains. "Average heights of 8000 feet are reached within five miles. Streams cut deeply into this section of the mountains. V-shaped ravines with steep stream gradients...are prominent." (Motel, p. 4) The fountain formation which makes up Boulder's Flatirons has also been uplifted and exposed in the area.
The rocks, hillside and mountains of Eldorado Springs are what make the area a beautiful place to live. But this environment also has many geological hazards. In some areas land slides occur. Obviously, building a home in an area of serious hazards is unsafe for the residents of that home, but the problem affects more than just those residents. Moreover, new construction in an area of serious hazard can affect the residents who live around the area. (E.Springs, P. 5)
THE COMMUNITY DEVELOPMENT APPROACH
The Center for Community Development and Design, which provides technical assistance to communities and non-profit groups, uses a community development approach to problem solving. The Center's Small Town Planning Unit uses a method of community planning developed by Mark Murphy, former director of the unit.
Roland Warren defines community development as:
a process of helping community people analyze their problems, to exercise as large a measure of autonomy as possible and feasible, and to promote a greater identification of the individual citizen and the individual organization with the community as a whole. (Christenson, p. 10)
In many ways community development is the embodi ment of democratic society (Christenson, p.viii) Communication, debate and compromise are its key ingredients. *
The planning unit's approach resembles the informational self-help approach described by Howard McClusky:
participation leads to involvement and involvement leads to better understanding of process and issues. The result is a stronger identification with the commitment to the implementation of decisions.
(McClusky, p. 13)
THE COMMUNITY PLANNING PROCESS
Community planning was perceived by John Friedmann as charting courses of action into the future -a process that leads to the definition of organizational goals and their reduction to specific programs and courses of action (Friedman 1966, p.100). Friedman feels that the professional planner must be technically qualified but should also have an ideological stance (Friedman 1966, p. 101). That is, the planner should be willing to help achieve the measure of self-direction important to the community development approach.
The technical planner must have an ideological or moral commitment as well as an understanding of the comprehensive planning process and the social system wherein it works (Melvin, 1974, p. 40). in the planning unit's approach participation is the guiding rule. But technical problems sometimes require technical solutions. When this happens the planner as a professional provides alternative solutions, usually by developing a range of possibilities indicating the pros and cons of each (Murphy, 1981,p.5). The community must still make the ultimate policy decision even though the technician is a significant partner in the process. Friedman calls this a transactive approach when applied to the field of planning. This approach restructures the traditional client to planner relationship. It recognizes the value of the experiential knowledge of the planning professional. It attempts to blend and balance the inputs into a single guidance system.
Possibly the most important capacity of transactive planning is to allow value judgments to structure study results. Decisions about whether or not a town shall develop, how fast and in which areas are intensely political.
These are perhaps the greatest set of tangential considerations which enter the planning process. (Jones 1975, p.3). In this situation the planner is viewed as a social change agent whose audience is composed of the users, those people to be most affected by the plans. This approach requires the community planner to demystify and democratize the planning process so that the community can make informed decisions about its future.
The small town planning unit uses a problemsolving methodology that involves six sequential steps. They are: 1) problem identification and basic data research; 2) identification of issues/ conflicts; 3) development of alternatives;
4) discussion and modification of alternatives;
5) decision making and documentation of results.
-This contrasts with the more "common" plan making methodology which usually follows this pattern:
. 1) identification of problems and definition of goals and objectives; 2) data collection and interpretation; 3) plan formation; .4) review and adoption of plan. (Spangle, 1976).v Our method differs in that the definition of goals and objectives is left to a later stage. This allows the issues to be discussed up to the decision making point. It is felt that better goals and objectives are made after the "facts" are in.
The problem identification and basic data research was begun with the household survey and mapping study which are described in the research methodology section of this document. This phase proceeded along two tracks. While the physical characteristics of the community were being researched, mapped and analyzed, research was underway to identify the social aspects, problems and desires of the population. These two areas of study generated a series of incongruities.
For example, one of the main conflicts that needed to be addressed was the number of vacant lots platted on'steep hillsides. The research into the social aspects of the community came from direct questioning (through household survey and committee work) and observation.
The next major step in the project was the land use alternative study. This step required that conflicts between myth and reality, between constraints and opportunities,and between trends and people's wishes, be identified and presented to the committee for discussion. This stage relied heavily upon the residents' knowledge because of their familiarity with what worked or failed in the past, the operational details and feasibility judgments, and most importantly their values and priorities. The goal of this stage was to examine the many ways Eldorado Springs could develop in the future.
The basic method used to achieve consensus on this part of the project was through the use of regular small group meetings or design workshops. The small meetings allowed a rich exchange of ideas and made it easy for all in attendance to say something. Using scenario gaming techniques the residents could see their ideas developed, elaborated upon and put into graphic form immediately. They were also allowed to elaborate on their ideas and revise them.
Guided by the land suitability map, which was developed first, several scenarios of the future were generated. Each scenario was based upon a different combination of legal, environmental and land use assumptions. The ultimate goal was to give the steering committee an indication of what results could be expected if alternative directions were adopted. Decision making and documentation of results follwed this step.
THE PLANNING PROBLEM
As mentioned above, the scenarios provided a method of combining the social with environmental issues, allowing speculation on the impacts of each scheme. The scenarios were based on two main factors: 1) possibilities of future population growth and 2) the amount of vacant land suitable for town development.
A combination of these factors would provide a good indication of the communities' growth potential. Demand for land in Eldorado Springs was considered high for the reasons described earlier. (See Section 1 of this chapter.)
The key to the problem was to develop a method of landscape analysis in order to define how much land in the study area was suitable for development, why it was suitable and where it was located. This information, combined with the land use and zoning information, would give us an idea of the number of available building sites in the study area.
The solution had two main criteria First, it had to "fit" into the community planning process. Briefly, this means that the method had to state its assumptions, follow a logical line of thought, and be clear enough so that the steering committee would understand it.
Secondly, the method had to be responsive to the particular problems and needs associated with the project in Eldorado Springs. This meant the method had to apply to a complex environment within a small area and be understandable to lay people. The project constraints were that it needed to take advantage of information readily available, work within the time constraints of the project, and be easily comprehendible and available to the community. This thesis argues that our new method satisfied these criteria wel1.
LANDSCAPE ANALYSIS PRINCIPLES AND THEIR RELEVANCE TO THE ELDORADO SPRINGS PROJECT
As mentioned in the previous chapter, a method was needed to define how much land in the study area was environmentally suitable for town development. The discipline which seeks to determine land suitability based on environmental factors is landscape analysis. The purpose of this chapter is to discuss the field, its principles, and to determine their relevance to the Eldorado Springs project.
THE PURPOSE OF LANDSCAPE ANALYSIS
Since landscape resources (land, water, visual resources, etc.) are useful and finite, landscape analysis is used with planning as a mechanism to define the objectives of their use and allocate them in accordance with those objectives (Fabos, p. 13). Landscape assessment techniques seek to "reconcile the needs of competing land users and to incorporate them into a landscape in which man can prosper without destroying the natural and cultural resources" (NARWR study, p. 81). In summary the concept asserts that land, in its existing condition has inherent opportunities and constraints and that possibilities for its use can be identified.
LANDSCAPE ANALYSIS PRINCIPLES
The refinement of landscape planning principles has come only in the last twenty years due to the concentrated examination of the causes and effects of environmental change. (Fabos, p. 45) The mainstream of environmentally sensitive planning ideas came from Landscape Architects, primarily, Frederick Law Olmsted. (Fabos, p. 48) Olmsted's plans exhibited a desire to work in harmony with nature by preserving floodplains for protection and views for the enjoyment of the general public.
Landscape analysis can be capsulized into four main principles: 1) Development should be discouraged in areas of significant resource value;
2) development should be discouraged in areas of natural and manmade hazards; 3) development should be encouraged in areas best suited for it; 4) the ecological "carrying capacity" of the regional environment should not be exceeded. (Fabos, p. 56)
At this time, development suitability assessment processes are in a developmental stage. Several of the available techniques come not from the technical literature but rather from planning and design reports. These techniques seem to fall into three general categories: (1) development suitability techniques for a specific use on a particular site; (2) general development suitability or "site selection" models for a specific use; (3) comprehensive suitability assessments of
an^area of public jurisdiction for all major cate-.gories of development. (Fabos, p. 130)
THE COMPREHENSIVE APPROACH
The type of method needed for public land use planning is the comprehensive approach. However, the methods need much more refinement to be useful at the public level. The major drawback is assessing the physical environmental factors in a comprehensive manner with only partial knowledge of natural processes. (Steinitz, p. 280)
Although well developed comprehensive assessment techniques are not in existence some progress is being made in the area. According to Carl Steinitz, "none of the studies which we have described can be considered a method for detailed planning and design." All of them (16 studies were reviewed by Steinitz) are "first look" methods. (Steinitz, p. 284) In other words, a problem is determined on an area basis and further defined on site. These methods are applied in order to focus on areas which would then require more detailed investigation. Currently, these general landscape assessment methods such as those popularized by Ian McHarg are being used by some regional agencies (Fabos, p. 130) '
AN EVIRONMENTAL ANALYSIS OF ELDORADO SPRINGS USINGS THE
In the previous chapter it was determined that the type of landscape analysis method needed for public planning was the comprehensive approach. Unfortunately it was also determined that none of the suitability techniques investigated can be considered for detailed planning. During the project it was first thought that the McHarg method could be applied to the small area. This chapter will test that proposition.
THE MCHARG METHOD
McHarg believes that ecology provides the single indispensable basis for landscape architecture and regional planning. (McHarg, p. 105) His method is based on the proposition that nature is a process that responds to laws and that these laws provide either opportunities or limitations to human use. (McHarg, p. 34) He assumes that man, through his understanding of nature can contribute to its operation.
McHarg's main emphasis is in analyzing the natural environment to interpret natural processes as social values. This allows McHarg to perform a least social cost/maximum social
benefit analysis on the particular study area, One of the main advantages of this approach is the ability to consider many non-price benefits and costs such as scenic views. (McHarg, p. 35)
HOW THE MCHARG METHOD WORKS
McHarg begins his analysis by inventorying existing conditions and trends. This allows him to demonstrate to his clients what will happen to the study area if nothing is done to rectify destructive trends. Next, data is collected in the follow ing categories: climate, historical, geography, physiography, hydrology, soils, plant association and land use. By using a sequential overlay process, "McHarg feels that an analysis can be based on the historical reasons for an area's resource patterns." (Steinitz, p. 177) Each of the categories are mapped on a color transparency, and the data is interpreted in a series of maps of "intrin sic suitability" (McHarg, p. 154) The transparent maps are then superimposed upon each other until they are all overlaid. The darkest tone represents the sum social values and physiographic obstructions. (McHarg, p. 35)
McHarg's method has several positive aspects.
First, the evidence is derived for the most part from the exact sciences. This is of great advantage because as the ecological sciences become more accurate the more sound the method becomes and may eventually be quantifiable. Second,
McHarg claims that his method is "explicit"
(McHarg, p. 105). In other words, another person accepting the method's assumption and evidence is likely to reach the same conclusions. Third, the method includes important factors that are not traditionally included in a formal cost benefit analysis. This permits him to derive a relative value of an area based on the comparison of color value. This may allow the community to apply its own value system to the environmental analysis.
permits him to derive a relative value of an area based on the comparison of color value. This may allow the community to apply its own value system to the environmental analysis.
Another useful aspect of McHarg's method is that through proper use of the method predictions are possible. (Steinitz, p. 306) Thus, McHarg predicts damage to urbanization should the flood-plain be developed.
ENVIRONMENTAL ANALYSIS OF ELDORADO SPRINGS
The following is an analysis of the major environmental factors in the Eldorado Springs area Each of these factors was identified and mapped prior to this study. For purposes of time and expense color was not used in this analysis. It
is believed that the method will work as well in black and white. Climate and historical geography were not considered in this analysis because the available information did not lend itself to be mapped at the small scale.
McHarg usually limits his slope suitability to no greater than 5% for urbanization. (Steinitz, p. 180), however, for this study we will use the guidelines determined by Boulder County which are 0-20% low hazard; 20-50% moderate hazard; above 50% high hazard.
Mountain torrents arid flash floods are local, sudden and sometimes catastrophic short-lived floods of relatively great volume and velocity. (NBC, p. 9) They can destroy essentially all works of man within the flood path and the associated erosion can undercut buildings that are above the flood. The only economically reasonable and physically safe mitigation is complete avoidance of these areas.
Whenever bedrock layers are exposed at the surface, natural weathering process begin breaking and fracturing it into smaller units. These areas are unstable surfaces on which to lock a foundation (Way, p.160). Since the hazard encompasses a large area and is by nature impenetrable (cannot go below it to a more stable layer), it cannot be mitigated without great expense.
A blockglide can occur in Eldorado Springs on slopes which have a coherent rock layer over-lying a weaker layer (as in sandstone and shale). This type of layering occurs in the hogbacks north and south of town. The fragile layer is exposed and fails to support the upper layer on the slope, causing the mass to ride downward. Again the best mitigation of this method is to avoid building in the area. In addition, cutting on a slope where block glide potential exists should be prohibited.
Rockfall can occur as block fragments of various sizes are weathered off the top of a rock formation. Rock falls can demolish structures and kill people. (NBC, p. 30) Any structure in the path of a large rockfall is subject to damage. The best way of dealing with rockfall is to avoid areas where rockfalls are naturally prevalent. (NBC, p.33)
Shale is a sedimentary rock which is fairly impermeable to water and when exposed weathers easily (fractures into smaller units). It is dangerous to development when a shale layer underlies a more permeable rock such as sandstone, and the shale becomes exposed. The shale can weather away and create an overhang on the sandstone outcrop, creating a potential for fracturing and collapse. The mitigation of this hazard depends on the nature of the shale itself. Fragile Morrison shale is considered more dangerous than Nirobrara, Smokey Hill, Benton or Pierre shale. (Way, p.185)
Soil creep is common on a steep slope which has a thin soil cover over the bedrock. It can be seen as an indicator of a more serious slope failure in the future. (NBC, p.38) The mitigation of soil creep requires that the slope of the hillside be changed to a lesser angle to decrease the soil movement. Retaining structures can also be installed.
Slumps are the most common of slide types of mass wasting. (Brunsden, p. 135) They are the result of either a decrease in resisting forces holding the earth mass and/or an increase in the driving forces that facilitate its movement.
The mitigation of this hazard is similar to the soil creep method only on a much larger scale. These techniques can be quite costly. In general, recognition and advoidance of these areas with all structural land uses is desirable. (NBC, p. 81)
Swelling soils are soils which increase in volume as they dry out. The powerful force of expansion is capable of exerting pressures of 20,000 psf or greater on foundations. (NBC,p.39) Methods for building in and on swelling soils are well developed; there is usually no reason to avoid construction, provided the appropriate engineering measures are taken.
ALLUVIAL EROSION; The northern flash flood corridor located on the flood plain map under the geotechnical study has a channel area. When flooding occurs, this channel would be susceptible to deeper channel cutting and possible foundation undermining.
RIVER EROSION BANK: In tbe case of a very high flood water (500 year flood
or more) coming down the canyon, it would blow out at the canyon mouth (base of the Bastille) with tremendous force. This flood water would naturally tend to follow astraightchannel from its source rather than the rivers present curved channel through town. Consequently putting more stress and erosion concentration against the north bank of the river in town resulting in channel cutting and foundation under-mining.
AGGRAVATING CIRCUMSTANCES OF HAZARDS
Hazards can often be made worse by construction. For example, an increase of mass on unstable slopes with a structure and the equipment needed to build and service that structure can cause slope failure. Septic dispersion fields add water which increases the weight of the slope.
If the natural drainage patterns are disrupted the resulting erosion can cause a loss of vegetation. The fluid itself can decrease the resistance and shear strength. (Brunsden, p.60) Excavation for foundations, basements, driveways, etc. can interrupt a slope's integrity. Even vibration from construction equipment can cause a landslide. (NBC, p.80)
The impacts of development on wildlife and vegetation are not easily recognizable and occur over long periods of time. These changes displace certain specie populations from the area and may become a critical problem if it is a reproduction or a food collection area.
The following areas were considered of high social value or dangerous to develop for the purpose of this analysis.
High Natural Hazards Slope greater than 50%
100 year flood plain flash flood corridor Slope failure by slump Rockfa 11
Fragmenting bedrock Block slide
Fragile Morrison shale
Moderate Natural Hazards
Moderate slope 20-50%
500 year flood Alluvial high erosion Alluvial river erosion bank Expansive clay soil severe
Low Natural Hazards Colluvium Creep
Expansive clay soil moderate to low Gentle slope 0-20%
Ecosystems Sensitive to Development High riparian
Moderate Ponderosa and Douglas Fir stands Low dry shrub
*The composite map of these factors overlaid appears on page of this study.
PROBLEMS WITH THE MCHARG METHOD
The McHarg method was rejected in the field based on the planning team's determination that we could modigy it to better fit our situation. One of the major problems with the McHarg method is that the factors cannot be added up as he implies. In the preceeding example (see map "McHarg Method") which involved two major categories of environmental constraints, sensitive ecosystems and environmental hazards are not based on the same social value. In other words, the implications of building in a hazard zone is taking the risk of physical harm. Development in a sensitive ecosystem may cause harm to the residents but the likely possibility of this small. Development in sensitive ecosystems will probably harm the micro-ecosystem. Sensitive ecosystems should be protected but we do so based on a different value. Thus McHarg makes an oversimplication by his implication that all categories, when combined are combined with equal weight. (Steinitz, p.J2*-(). McHarg admits this fault himself. "While there should be little doubt as to the ranking within a category, there is no possibility of ranking categories themselves." (McHarg, p.34)
The method was also considered by the planning team to be too general for small scale mountain areas. The best example of this is his inclusion of slope as a major environmental factor.
Slope is not the hazard but merely an indicator of unstable hillside. It is slopes with certain geological formations that are potential hazards. Also the method overgeneralizes for the small scale from a cartographic point of view. The cartographic procedure for the McHarg method was to categorize the information, to rank order it, and then map it in an overlay series. The planning team thought it could add distance between the rankings because our information was more
specific and our scale of mapping was accepting of the added information. The McHarg method has no procedure for determining the distance between the rankings.
An associated problem with the method is that a consolidation of many specific variables into broad categories is considered to be necessary.
A drawback of this procedure is that in combining key elements, one very often finds the same basic variable appearing many times only slightly different . Topographic slope provides a
good example. It is the basis for the definition of several key elements such as rockfall danger. The McHarg Method does not always recognize the degree to which the final cumulative measure reflects the multiple or singular use of specific variables. Thus key elements, let alone summary evalution9, combine what in essence are apples and oranges. (Steinitz, p. 125)
Another principle feature of the McHarg Method is that there is no provision for the determination of social values. It is assumed that the assigned values are determined by his staff based on their professional judgments.
The team believed that the McHarg method could be improved if modified in the following areas: First, the composite map could be made more specific if we used a numerical rating system rather than a tonal system to indicate the importance of the ecological factors. Second, it could be made easier to understand if only one basic social value were used rather than several. The social value that the method is based upon is encompassed in the idea that environmental hazards should be mitigated or avoided to insure
the health, safety and welfare to the community. Third, the method could also be made clearer if the actual hazards were identified on the map instead of shown in a general form such as a tone. The implications of development in hazard areas could also be explained in the document.
LANDSCAPE ANALYSIS FOR MOUNTAIN COMMUNITIES
This chapter will discuss how the McHarg method was modified to meet theneeds of our situation in the Eldorado Springs Project. As mentioned in Chapter 2, a stage of the Comprehensive planning process required a landscape analysis method to determine how much and when there existed land suitable for development based on environmental factors.
It was believed that the McHarg method could be improved if modified in the following areas: First, the composite map could be made more specific if we used a numerical rating system rahter than a tonal system to indicate the importance of the ecological factors. Second, it could be made easier to understand if only one basic social value were used rather than several. The social value that the method is based upon is encompassed in the idea that environmental hazards should be mitigated or avoided to insure the health, safety and welfare to the community. Third, the method could also be made clearer if the actual hazards were identified on the map instead of shown in a general form such as a tone. The implications of development in hazard areas could also be explained in the document.
HOW THE NEW METHOD WORKS
The new method is dissimilar to the McHarg Method in several areas. First, the environmental factors are not generalized in the analysis stage. The specific factors are indicated on the map. This way the extent pf the factor can be seen as wel1 as the interrelationship of several factors together. For weighting, the individual factors were assigned a hazard code from one to nine based on the relative cost or possibilities of mitigation. These determinations were obtained from engineers (floodplain) and environmental geologists, either through the literature available for the area or from actual field inspections.
Second, a numerical system replaces a tonal system for indicating the weight of a factor. The numbers allowed a more exact weighting to be imposed. It also allowed the distance between factors to be detailed. The numbers were important when we established a specific cutoff point based on a particular number.
Third, the color system was replaced by a black and white system which is easier to apply (color is extremely difficult and expensive to reproduce) .
Fourth, the method is dissimilar to the McHarg Method in that the values of the users were reflected in the method. This was done through the process of intimately involving them in the development of the project.
Each environmental factor is given a high, moderate or low rating of danger with regard to development. High risk hazards were assigned a numerical value of 9, moderate a value of 3, and low a value of 1. This point system provides a way to evaluate areas in which two or more factors occur together by giving a cumulative risk value to the area.
The key to the method is in the cut-off point which identifies "land suitable for development" as having a total value less than 9. The cutoff point is based on the high risk factors which were determined to be where the extent of mitigation is so extreme that the most reasonable alternative was to avoid the area entirely.
The "visual message" of the methods also differ. The McHarg Method merely divides the landscape into a range of urban suitability from high to low. The assumption presumably is that areas of high suitability should be developed first.
It also identifies opportunities for certain uses, especially those which are in conflict with urban development. The method does not provide direction as tb where development should be stopped.
The visual message of the new method is distinctive because it draws a clear line that delineates where town development should and should not occur and communicates why.
In simplifying the method, we unfortunately did not achieve all of what landscape analysis attempts to do. A principle problem was that our method failed to identify opportunities for certain types of uses by concentrating on constraints. We were also constrained by the fact that specific information as to the human hazards of other environmental factors were not available. Thses had to be left off the map. We considered only those environmental factors where the related professionals (hydrolisic engineers, geologists, etc.) were willing to make a prediction as to the effects of development on the human environment.
A more comprehensive analysis which more closely defined the ecological carrying capacity of the study area would have been more sound based on Landscape Analysis principles.
THE METHODS APPLICABILITY TO SIMILAR SITUATIONS
The method's major advantages appear when dealing with the problems encountered in the Eldorado Springs Project. In our case, the method was an aid in plan making in the small scale but complicated natural environment of a mountain community. Our-weeds were only that the me.thod work with the community planning process. This was accomplished by simplifying the analysis to include only hazards which made it more acceptable in the citizen participation process. The mefhod was, at the same time, made more specific by including the actual hazard which made the method more acceptable in small area analysis.
The method also has an advantage in that it is based on a well accepted value which most small towns can agree with. A method which defines land suitable for development as all the land with the exception of the most dangerous areas ishould be easy to implement.
The purpose of this study was to present the landscape analysis method developed for the Eldorado Springs Project, the premise being that it could apply to similar situations.
The method was designed to be a research tool to aid in plan making for small mountain communities. Our priority that the Method "fit" into the community planning process was not only achieved but became inseparable to the new methodology.
"A tool consists of a use on one end and a grasp on the other. Tools, uses and grasps and ultimately users all coevolve with each other.
A tool or technology that doesn't push its user around qualifies as "soft". The difference between hard and soft technology is the difference between a command and an understanding. (Brand, 1980, p. 132) The participation requirement of the community planning process led to the involvement of the local residents which led to a better understanding of the issues and processes. This was directly observed by the planning team through the household survey, the small group meetings and the design workshops.
The benefits of involving citizens was the reflection of community values in the new method and the citizens' greater identification with the project and commitment to its implementation. The method is appropriate to small mountain communities because it takes both environmental and social concerns into consideration. It is helpful to planning because it identifies land environmentally suitable for development and explains why.
This method naturally owes much to the McHarg Method which was its basis. The major distinctions of this method is that it clearly defines where development should and should not occur and bases that definition on a strong community value. The final land suitability map was field checks. It delineates two small corridors on either side of the canyon. The sites are pleasant, gently sloping and appear to be comfortably habitable.
The responsibility of planning and protecting the mountain environmental quality lies with all of us. The responsibility of enforcement of this responsibility on private lands, however, lies with the local county and town governments.
Some, particularly the small rural communities, often lack the necessary resources to fulfill their planning responsibilities. (Nichols, p.l)
A review of development considering environmental factors could save a considerable amount of environmental damage. Mountain town development often takes place on a lot by lot basis and because the lots are small, siting problems can often be kept to a minimum. Simply by reviewing a development to make sure it is in an environmentally appropriate area, many "small" mistakes would not be allowed to become problems that are beyond the fiscal abilities of the local community to rectify. A review would be easy if the commissioner had a map in which to locate the development and question its wisdom on a natural environment basis. The method provides such a map.
During the succeeding steps taken in the Eldorado Springs Project, the team used the land suitability map as a starting point to decide if the site needs of town development could be provided. Issues such as access, circulation, water supply, sanitary sewage disposal, removal of refuse, police and fire protection were either assumed or investigated further. Vacant land rights and mitigation techniques for sensitive ecosystems were also investigated. Because of the detailed scenario development, predictions of growth in the area were more confidently made.
Unfortunately, a detailed investigation of the major factors affecting the growth and its impacts on an area is beyond the scope of most mountain communities. A landscape assessment which gives a more comprehensive picture of the environmental impacts of town development would be a great help to both planners and community leaders. One of the chief problems of the method as currently developed is that the environmental factors considered are limited to those environmental fields which are developed enough where predictions can be made as to the impact on the human environment. When the predictions come in and the professionals are willing to stand by them they can be added to the maps. To accomplish this, more needs to be known about the man-nature ecological rela-tionshi ps.
In summary it is concluded that the method met the needs of the Eldorado Springs Project and appears to be applicable to other mountain communities. It is believed that the map could be incorporated into a zoning ordinance because of the clear line it defines for land suitability. However, a future study could help to determine whether a land use plan based on the land suitability map could be implemented.
Brunsden, Denys and Doorkamp, John C., eds.
The Unquiet Landscape. Bloomington: Indiana University Press, 1974.
Christenson, Janies and Robinson, Jerry W., Jr., Community Development in America. Ames: The Iowa State University Press, 1980.
Colorado Geological Survey. Proceedings of the Governor's First Conference oh~Environmental Geology. Denver: Colorado Geological Survey Special Publication #1, 1969.
Fabos, Eugene P. Planning the Total Landscape. Boulder: Western Press, 1980.
Freidmann, John. "Planning as a Vocation." Planning 9, December, 1966.
Hendler, Bruce. Caring for the Land. Chicago: American Society of Planning Officials, 1977.
Howe, Charles W., Chairman. Residential Development in the Mountains of Colorado, a Survey of Issues. Denver: United Banks of Colorado, 1972.
Ives, Jack D. and Barry, Roger G., eds. Arctic and Alpine Environments. London: MethuerT~&
Co. Ltd., 1974.
Jones, Bernie. "Doing Sociology with Design Professions." Paper read at the 39th Annual Meeting of the Midwest Sociological Society, Chicago, Illinois, April 9, 1975.
Lynch, Dennis L. and Broome, Standish R. Mountain Land Planning. Fort Collins:
Colorado State University, 1973.
Lynch, Dennis L. An Ecosystem Guide for Mountain Land Planning. Fort Collins:
Colorado State University, 1974.
Marsh, William M. Environmental Analysis for Land Use and Site Planning. New York: McGraw-Hill, 1978.
McClusky, Howard Y. "The Informational Self-Help Approach" in Approaches to Community Development. Iowa City, National University Extension Association and the American College Testing Program, 1973.
McHarg, Ian. Design With Nature. Garden City, N.Y.: Natural History Press, 1969.
Melvin, Ernest E. "The Planner and Citizen Participation." Journal of Community Development Society 9, January 1974.
Motel, Cornelia F. From Grassland to Glacier, an Ecology of Boulder County. Boulder:
Johnson Publishing Company, 1976.
Murphy, Mark C. "Out of the Classroom, into the Field: Teaching Community Development in Rural Colorado." unpublished article, 1980.
Nichols, Kevin. "Controlling Hillside Development in Front Range Communities." Masters Thesis, University of Colorado, 1979.
North Atlantic Regional Water Resources Study Coordinating Committee, North Atlantic Regional Water Resources Study. Washington, D.C.:
U.S. Government Printing Office, 1971.
Pendleton, James Abercrombie. Conduct of Local Government." University of Colorado, 1978.
"Geology and the Ph.D. dissertation
Robinson, Arthur H. and Sale, Randall D.
Elements of Cartography. New York: John Wiley & Sons, Inc. 1969.
Shelton, David C. and Prouty, Dick. Nature's Building Codes, Geology and Construction in Colorado. Denver: Colorado Geological Survey Special Publication #12, 1979.
Spanghe, W. & Assoc., Leighton, F.B. & Assoc., and Baxter, McDonald & Company. "Earth Science Information in Land-use Planning -- Guidelines for Earth Scientists and Planners." U.S. Geological Survey, Circular 721, 1976.
Steinitz, Carl, et al= "A Comparative Study of Resource Analysis Methods." Department of Landscape Architecture Research Office, Graduate School of Design, Harvard University, 1969. (Xeroxed edition)
Tweeten, Luther and Brinkman, George L. Micropolitan Development. Ames: Iowa State University Press, 1976.
Ulman, Dr. Wilbert J., Mountain Recreational Communities and Land Use. Denver: Colorado Land Use Commission, 1975.
Way, Douglas S. Terrain Analysis. Stroudsburg Dowden, Hutchinson & Ross, Inc., 1973.
Webber, Patrick J. High Altitude Geoecology. Boulder,: Westview Press, 1979.
r. ' * >. v'i ' * f' ii *v
;:'"\;v*>5SSc.-'.' ; ">*.' .'"
f v/.' CC i f'fc&Wtfiy',
&v ^ *
' *-Â£V> :'*:
n^h f i W-
* ;**. : i .* r K.I*li^
S/AlE >00 SCAiC IN FEÂ£T
0 i00 200
CONTOUR INTERVAL 20 S 40
SOURCE OF INFORMATION-
4* (.. i ^ m.is ptnro-. s (; */
*v I0ft"-b04 t*t i v'i /iO/r IV < 8 4*OC JO/ft
FRAGMENTING BEDROCK 'BaJ FRAGILE MORRISON SHALE COLLUVIUM CREEP- LOW COLLUVIUM CREEP- HIGH
ELDORADO SPRINGS MAPPING STUDY
. rO .
*, *a o # 0#* 4
^Y Xt**-*^^ Tr^
v ^ ^ . ,* j
OX -vS-V^' '^\/-
! ';: V:>-YUY
: v .
f. V: >v> V .>;;.. i AX -V ft /.. .. V'
w p- /..
kt,o ** .
., v *v 'VX-^vVV vX-:
1 Y -T \ \*L*V- '-. N*' *' ;
v t .' > 'W ...
\v 1 # x,-.- <
.'X^ v. : \ <
|ifg|. Yv'x- A 7
^ y. i .-' '-V.
i "vSi> v
V *V!''A "v?'' .'V i:r\ l' 1 *; \ -, i*
v3 \ *'* !.%. i y L* .A r- \ |> \ l, f i.
& \ v\ . 1 .f 2 V ML/.
-/ xi v
*CA41 l 100. ^CALt M FICT 0100 200
COWTOUH fWTEUVAL. 20 0 40
SOURCE OF INFORMATION-
CAST us (1 i ,TS'MM4,1*S, rMOfOHfViStD rtMl CAtT UMniOOfl MCA ft AtSOC 7/10/T (IT >CM MOO At M ASSOC S/IO/Tt
MORRISON FORMATION1 BENTON SHALE. OAKOTA GROUP NIOBRARA FORMATION SMOKEY HILL SHALE
PIERRE SHALE LYONS FORMATION FOUNTAIN FORMATION SILTSTONE
ELDORADO SPRINGS MAPPING STUDY
SCALE I* IOO SCALE IN FEET 50. 0 100 200
CONTOUR INTERVAL 20' 8 40'
SOURCE OF INFORMATION5
EAST s U.S.6.S.,7.5SERIES, 1965, PHOTO REVISED 1971. EAST CORRIDOR R.W. BECK a ASSOC. 7/10/73. WEST > C.R.MOORE a ASSOC. 9/20/78.
HIGH URBAN SUITABILITY
LOW URBAN SUITABILITY
ELDORADO SPRINGS MAPPING STUDY