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inTroducTionThe purpose of environmental planning to the catalogue, assess, and mitigate the ecological resource that contribute to our cities. More importantly the environmental goal to better integrate the environment into the urban and suburban densities, to that the native species have the ability to prosper as much as the human inhabitants.

Environmental planning is the proactive decision process to guiding human and environmental interactions, management of ecological resource to the best potential for human and wildlife alike, and fiscal responsible that encourages health for the human and animal kingdoms1. In its proactive application, instead of a reactive practice which is common in typical environmental management, the guidelines and designs that are established at the forefront of the community project.

sensiTiViTy analysis

The project describes a site sensitivity of the larger region of the Santa Cruz Watershed. The process is to identify soil types, land cover and canopy, and slope and the solar direction of those slopes. Following the identification process each element of the region is hierarchically ranked on priority to sensitivity to human influence, these elements are to be protected and/or preserved. Through the analysis land areas will be located that are least acceptable of human corruption, these may be use for future developments with little consequence. However, policies must be implemented to manage human influence on the environment whether or not the area is most or least sensitive.

new deVeloPmenT

After the sensitivity analysis of the entire watershed, the study focuses upon a smaller basin located within the Santa Cruz Watershed, the Mid Tanque Verde Creek Basin. This basin is located on the east end of Tucson, Arizona, an area that has seen recent residential and commercial developments. Utilizing the previous analysis, 3 more analysis overlays are applied to develop Green Infrastructure. A distance raster is created from the major and minor washes, and a 100 feet (200 feet total) buffer is applied to the hydrological accumulation data set. Through these techniques suitable land is located for the residences and commercial properties and conservation easements are designated to protect the waterways from increase of surface runoff pollutants. Moreover, these conservation easements may require additional educational awareness from the planners to the existing residence to prevent environmental contamination and damages.

1 Daniels, Tom and Katherine Daniels, The Environmental Planning Handbook. American Planning Association, Chicago, IL. 2003. Pg. 11

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hydric soilsThe importance of identifying hydric soils, or soils that potentially contain excessive amounts of soil is because they may pose possible instability in the subsurface soils horizons when saturated; turning into a slurry substance or increase the possibility of erosion1. On the other hand, soils that my have high permeability rates are desirable to conserve for possible groundwater aquifer recharge. The soil texture and vegetation are essential for groundwater recharge2. Unfortunately, the soil texture that provide high, or moderate permeability are more acceptable to erosion, thus the need to maintain vegetation land cover within the area3.

1 Marsh, William M. Landscape Planning : Environmental Applications. Reading, Mass.: Addison-Wesley, 1983. Pg. 1032 Steiner, Frederick R. The Living Landscape : An Ecological Approach to Landscape Planning. New York: McGraw-Hill, 1991. Pg. 753 Marsh, Pg. 261

farmland soilsFarmlands soils are important to hold in reserve because of the increase of city sprawl within the last decades, thus amplifying the depletion of food productive lands. On the other hand, if these soils are not in use as agricultural use, crop production or cattle-pasture, these should be protected from development because of the high permeability rate. This high rate aides in water infiltration and aquifer recharge due to the soil texture. Finally, the farmland as a soil group should be held in reserve to protect crop potential soils from development because of the ever increasing human need for land and expansion and to protect from contamination4.

4 Muckel, Gary B., Center National Soil Survey, and Service United States. Natural Resources Conservation. Understanding Soil Risks and Hazards : Using Soil Survey to Identify Areas with Risks and Hazards to Human Life and Property. Lincoln, Neb.: USDA-Natural Resources Conservation Service : National Soil Survey Center, 2004.2

land coVer Land cover is particular important to the Sonoran Desert and the Santa Cruz Watershed because it assist in soil retention along and in washes. In addition, assists in the transevaporation of groundwater to cool the climate, and provides migratory corridor for native animals. The vegetation types that are the highest priority are the wash and the creosote bush flats; the former is characterized by bursage, desert broom, and willow, parallel to the wash are woody species such as the blue Palo Verde and ironwoods. These woody elements provide soil stability to the sides of the washes, increase the angle of repose from a typical 3 deg to 40 deg or 55 deg5. The later, bush flats or shrubs are the most abundant of the vegetation types, they assist in animal habitats and retains the soils, preventing erosion by winds6.

5 Marsh. Pg. 736 Marsh. Pg. 100

canoPyWithin the desert region there are “sky islands” of deciduous and evergreen forests that provide immense habitats for native species. In addition, these forest systems offer escapes for the desert inhabitants for the cool of the summer and shade. Finally, the denser the canopy the less erodibility, the is because the canopy decrease the velocity of falling rain during the heavy rain seasons and the root systems of the trees assist to hold the soils in place7.

7 Marsh. Pg. 2613

solar asPecTSolar orientation provides micro-climate and special characteristics of the Sonoran Desert. The South slopes contain the desert shrub and cacti that visitor are familiar. More importantly these South slopes are the home to the Saguaro Cactus, which have been described as the “desert condominium”8. The North face slope contain special biomes of firs, chaparral, and trees that are not typical to the draught, hot-tempered south face slopes9.

sloPe

8 Steiner. Pg. 1159 Steiner. Pg. 103

The slopes are defined by the slope intensities and by the engineering degree standard, less than 5 deg (less than 5% slope) there is low probability of erosion, thus less sensitive, between 5 deg to 15 deg (less then 27% slope)allow certain home sites, 15 deg to 75 deg (greater than 27% to 100% slope), the maximum in the region, is unsuitable and most sensitive to erosion. Erosion will accelerate if these steeps slopes occur where sandy, well-drained soils are located due to the lack of cohesion between the particles. The red to deep red classification is the most acceptable to erosion and transport of earth deposits to the lower slopes and elevations, which created the alluvial fans located at the outlets of stream valleys10. In addition, slopes and hillside should be protected due to their significances for wildlife habitation and aesthetics11.

10 Marsh. Pg. 254, 25711 Mandelker, Daniel R., and Roger A. Cunningham. Planning and Control of Land Development : Cases and Materials. Indianapolis: Bobbs-Merrill Co., 8th Edition, 2011.4

FEATURE CURRENT CLASSIFICATON RECLASSIFICATION COMMENT WEIGHTED OVERLAY

HYDRIC SOILS B - Moderate 3

C - Slow 2

D - Very Slow 0

FAMRLAND SOILS 4 - Prime with Irrigation 3

0 - Not Suitable for Agricultural 0

LAND COVER Open Water 3

Develop | Open Space 3

Develop | Low Intensity 2

Develop | Medium Intensity 1

Develop | High Intensity 0

Barren Land 0

Forest | Deciduous 3

Forest | Evergreen 3

Forest | Mixed 2

Shrub | Scrub 2

Grassland Herbaceous 1

Pasture | Hay 0

Cultivated Crops 0

Wetlands | Woody 3

Wetlands | Emergent Herbaceous 2

CANOPY 0 - 25% 0

25 - 50% 1

50 - 75 % 2

75 - 100% 3

SOLAR ASPECT (-1) Flat 0

(-1 - 30) North 3

(30 - 90) Northeast 1

(90 - 150) Southeast 2

(150 - 210) South 3

(210 - 270) Southwest 2

(270 - 330) Northwest 1

(330 - 360) North 3

SLOPE DEGREE 0 - 5 deg. 0

5 - 15 deg. 2

15 - 25 deg. 3

25 - 74 deg. 3

The priority of the items are rated in their importance to the region: Open Water (3) because of its scarcity, Open Space (3) because it

should be protected within the urban and the intensity of development is rated from Low (2) to High (0), Barren Land does not need to be protected, Evergreen and Deciduous Forest (3)are of high

priority due to their elevation diversity and animal habitat, Mixed Forest and Shrub, Scrub (2) mid priority due to the abundance of

shrub type in desert, Grassland (1) is a low priority due to its scarcity, its lack of erosion control and though not discussed is

typically an invasive plant located to water tanks and holes created by ranchers, Cultivated Crops and Pasture or Hay (0) is least

sensitive thus does not need protection, finally Wetlands: Woody (3) and emergent Herbaceous (2) are detailed as the high and mid

priorities because of their importance in soil retention along and in washes and provide species migratory corridors.

3

Slope is prioritized in degree steepness; 15 deg to 25 deg or more is rated (3) due to high erodibility and sensitivity to human influence, 5

deg to 15 deg (2) because it may be suitable for certain home development but is still acceptable to erosion due to soil texture, and 0 deg to 5 deg is rated at (0) because there is little to no possibility

of erosion or landslide.

3

2

B is selected as highest priority (3) because it is the most permeable but the most erodible.

South and North face slopes are the most unique and distinctive to the Sonora Desert. The saguaro cactus only grows upon the south slope along with many other lowland draught tolerate cacti and shrub. The north face creates a micro climate of cool air in the mountain shade, pine and chaparral trees common to the upper

Sonoran desert are distinct to these regions.

Canopy provides species habitat and prevents soil erosion by absorbing the force of rainfall in its leave, trunks and branches, and

decrease sheet erosion by the roots and trunks. 100% (3) is the highest and 0% is the lowest.

Prime farmland is selected due to the increase of urban sprawl, it's high infiltration rate, and nearness to the water table.

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2

1

Table #1 hierarchal rankinG

weiGhTed sumThe site analysis maps are then given a hierarchal rank or rate of priority to the sensitivity to human influence and their importance to environmental management. After each element within each map is ranked in hierarchy against neighbor, such as barren lands (0); little sensitivity versus forest

(3) high sensitivity, each map is overlaid and the element values are summed. These sums vary upon the importance (0 - 3) that is given to each analysis. The purpose for the weights, or ranking is to demonstrate areas of the environment that is most sensitive and should be avoided from future human influence, and if needed protected from encroachment.

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2 32

1 3 1

sensiTiViTy oVerlayThe previous studies and their ranked values are overlaid to create a matrix which describes the least to most sensitivities areas of the Santa Cruz Watershed. The map to the right is the final overlay where green is the least sensitive and red is the most sensitive, thus more prone to human influence and must be protected or preserved. This map demonstrates the south and north slopes of the mountainous and foothill regions to be very sensitive to encroachment due to the vegetation biomes and the micro-climate of the north faces (shown is deep red). The valley floors are least sensitive

(green), but this does not imply that these areas are not acceptable to human influence and corruption. The floors are green because priority was given more to slopes and land cover more than hydric and farmland soils, fortunately due to the hierarchical nature of the overlay, prime farmland soils are a medium sensitivity (yellow to orange) thus these lands must be preserved against future urban expansion12.

12 Model #1 of Index, Pg. 156

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mid Tanque Verde creek basinThe Mid Tanque Verde Creek Basin is part of the larger Santa Cruz Watershed, its location is to the east of Tucson, Arizona at the edge of the city limits and urban development. Within recent decades home development has encroached into the ecological systems, bringing an increase of impervious surfaces that increase surface runoff and erosion, non-point source pollutants into the waterways, and displace wildlife habitat and migratory patterns.

The object of this study to locate acreage to support future 1000 residences and possible commercial developments. In addition to calculating the required residential, infrastructure was calculated at an additional 15% of the required acreage to support the additional residences, and finally educational acreage was found at 5% (this number is to acquire tax base for future funding of school sites).

In addition to the residential and commercial component, there is the accelerate need to Green Infrastructure. Green Infrastructure is a connection of parks, waterways, migratory corridors, natural hazards, and other environmental systems that aide in the health and mobility of animals, critters and humans13. These series of connected outdoor living spaces aide in the air quality of the city through filtration of pollution and dust particles, provide park space for pedestrians, cyclist and the possibility to build network of alternative modes of travel.

13 Randolph, John. Environmental Land Use Planning and Management. Washington D.C. 2004. Pg. 98

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hydroloGic accumulaTionThrough the use of Hydrological Unit Classification (HUC12) and classifying the units into only a High and Low breaks in ArcGIS establishes the washes in the region with the possible occurrence of accumulation of rainwater. It is these wash areas that must be avoided in future developments to diminish disturbance of the riparian vegetation which assist to maintain soil stability and maintain wildlife migratory patterns and habitat. Moreover, these riparian corridors provide aesthetic appeal for their diversity of wildlife, variety of vegetation16, and assist in the micro-climate by reducing heat through transevaporation.

These riparian corridor aide in the alluvial water aquifer recharge17. This is very necessary to maintain balance water supply and demand for not only the human desert inhabitants but also of the wildlife. The accumulations were buffered as shown below.

16 Marsh, Pg. 294, 314 & Steiner Pg. 7717 Marsh, Pg. 314

Green infrasTrucTureThe Green Infrastructure is identified by the acquired “flow-accumulation” of the hydrological unit classification through ArcGIS. Theses areas of high water accumulation, especially during the heavy rain season “monsoon” provide ideal corridors for wildlife and possible human enjoyment. These streams are the woody and emergent herbaceous wetlands that are essential for soil retention and wildlife diversity. The Green Corridor was developed by buffering 100 feet on both sides of the waterway, then using ArcGIS seeking land parcels that would intercept this buffer. In addition, a 200 feet buffer was applied to the existing national park to identify those parcel that encroach near these boundaries. The purpose is to select those parcels that cause an immediate danger to the quality of the corridor and to locate the vacant plots to create conservation easements. The conservation easements would retain the land from future development and maintain native habitat in larger parcels of land than just the immediate stream buffer.

Table #4 hierarchal rankinG of sensiTiViTies of The mid Tanque Verde creek basin

The table below prescribes the hierarchal ranking of sensitivities to define location suitable for residential and commercial development. In addition, it confirms the ranking of the previous sensitivity investigation for the Santa Cruz Watershed.

FEATURE CURRENT CLASSIFICATON RECLASSIFICATION COMMENT WEIGHTED OVERLAY

SITE SENSTIVITY High 3

Medium High 2

Medium Low 1

Low 0

IMPERVIOUS SURFACHigh 0

Medium High 1

Medium Low 2

Low 3

WASH DISTANCE 00 - 42 meters 3

42 - 106 meters 2

106 - 199 meters 1

191 - 400 meters 0

Wash distance is important to prevent alteration of the current drainage patterns, decrease the possiblities of downstream flooding. Moreover even the minor washes become micro-habitat for smaller

critters that are exxential to the desert ecosystem

2

Impervious surface are important to the servarity of runoff pollution. However in the grander scheme of elements, it is valued less because

it is not an element to protect but to mitigate through green techniques.

1

Due to the study of the Santa Cruz Watershed, which establish the ranking of priorities, high sensitive (3) are the highest priority due to

the possibility of erosion, habatiat loss, and permeabilty and contamination of soils.

3

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sensiTiViTy analysis of wash and imPerVious surfaceThe previous analysis that identified where the most and lowest sensitive land were in the Santa Cruz Watershed, now that analysis overlays impervious urban surfaces and distance intensities of the major and minor washes14. This analysis exposes the small rivulets that are common to the desert landscape, which gather surface runoff directed towards the greater washes. In addition, areas that are proper for development are expose in the green color, the areas that are orange to red are the most sensitive and must be avoided or apply mitigation practices15.

14 See Table #4, Pg. 1315 Model #2 of the Index, Pg. 16

ACREAGE OF ENTIRE BASIN AREA 30163.79 5916.03

ACREAGE OF NEW GREEN INFRASTRUCTURE 5718.78

ACREAGE OF NATIONAL PARK 18068.84

NEW RESIDENTIAL DEVELOPMENT 362.92

NEW COMMERCIAL DESTRICT 97.22

TOTAL OF NEW DEVELOPMENT 24247.75

ACREAGE DIFFERENCE

RESIDENTIAL PERCENTAGE ACRE

70% 254 3.3 838 15% 292 5% 307

30% 109 1.5 163 15% 125 5% 131

TOTAL ACREAGE 362.92 438

1,002TOTAL POPULATION

INFRASTRUCTURE EDUCATIONAL

TOTAL ACREAGE

GUD

Table #2 showinG The acreaGe breakdown by General land use

Table #3 showinG The acreaGe breakdown by residenTial l.u.

The new deVeloPmenTThe new development consists of two density types, 3.3 person per acre and 1.5 persons per acre. The purpose for the lesser person per acre is to maintain the existing rural character of the region that is east to Tanque Verde Loop. The 3.3 is a greater density than the typical 2.5 person per acre that common is Tucson. The purpose is to increase the density within the existing infrastructure without increasing the sprawl of the rural developments. The parcel selected were already established by the existing street infrastructure, that is maintained by Pima county, and vacant plots that lack homes.

The GreenPath that is constructed in tandem with any new development consist of pedestrian and cyclist paths separated from automobile roadway by native vegetation planting. In addition, the road construction is a “no-curb” policy that enables surface runoff into bioswales that run parallel to the road. There is a total of 16.44 miles of GreenPath to be redeveloped.

The tables above and below show the acreage breakdown by the entire basin, the existing park system and new green infrastructure, and the new commercial and residential developments.

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final ProPosal + summaryThe final proposal show to the right identifies the Green Infrastructure and the new residential and commercial development for the region.

The study utilized Digital Elevation Model (DEM) and Land Cover raster sets which further aided in the process of solar aspect and slope, identified sensitivity vegetation areas that must be preserved for the benefit on human and wildlife alike. The solar direction of any new develop is important to the situation of residences and homelife to take advantage of passive solar design, and to prevent devastation of south facing slope that contain abundant exquisite examples of the saguaro cacti. The DEM aided in the analysis of slopes that are sensitive to erosion, thus any disturbance to the surface cover would increase site erodibility and downstream flooding. The slope analysis also located the washes that may cause hazards to construction or any human structure near its edge. These slopes are also unstable due to the soil texture combined with the devastation of native trees and plantlife. It is essential for the stability of the waterway system that these washes are retained for woody and emergent herbaceous wetlands because of the importance to migratory patterns and the continuous vegetation root system stabilizes the wash sides. In addition, impervious surfaces were used to aide in the new development placement through locating the best parcels for infill construction.

Through the use of environmental planning, better integration of wildlife and human habitation can be constructed and maintained for the betterment of all. This integration demands proactive policies to prevent hazards, damages, interruption of native systems and damages to the built environment before environmental consequences become disastrous problems. In addition, through environmental planning ecological system can be preserved for animal and human alike, GreenPaths provide pedestrian and cyclist transport options and since western civilization has witness an increase of obesity and other health concerns, multi-modal transport must be a high priority for the built environment. GreenPaths provide shade for the ped|cycle, shade the pervious and impervious surface especially asphalt (blacktop), and reduce the heat island effect that has complicated the macro and micro climate of the desert region. These paths will have stormwater management (SWM) techniques implemented through the site; techniques include bioswales, pervious paving, depressed round-a-bouts at the intersections of minor streets, among others to aide in the capture and retention of surface runoff for filtration and aquifer recharged. Through this SWM techniques water quality can be improved for the city and the desert critters.

Additional human intervention techniques must be applied to prevent environmental damages:

1. Use of bioswales parallel to the roads to collect runoff and infiltration into the groundwater, because the hydric soils of this region is highly to moderate permeable alluvial fan, this provides an opportunity to collect and recharge the water aquifer.

2. Encouragement of native tree species planting along the minor and major washes to provide intense canopy cover and migratory corridors.

3. Aggressive removal of foreign, invasive plant species and education as to why these plants must be removed and prevented from growth.

4. Creation of Sonoran Wetlands to aide in groundwater aquifer recharge, filtration of contaminants, and recreational areas for the residences.

5. Infrastructure improvements of integrated pedestrian and cyclist routes with “no=curb” design to allow runoff into bioswales. Use of native species to separate ped|cycle from automobile traffic and to provide shade reducing the heat island effect. Moreover, favor ped|cycle more so than vehicle transportation.

6. Application of pervious driveways and commercial lots to prevent non-point source pollution runoff into the waterways.

7. Property use assessments on a annual or biannual period to evaluate the owners uses and determine if those uses may conflict with the environment. Also to educate the neighbor stakeholders to live sustainable within the Sonoran Desert.

Finally, this sensitivity analysis has demonstrated that residential and commercial plots may be located within a new development to least effect the surrounding environment. The analysis also identifies existing elements that are an accelerating concerns, such as the increase of impervious surfaces, sprawl of residential homes and lack of urban|suburban infill, and the continuous use of personal drives and cul-de-sacs which cause disconnected neighbors and excludes community members. Environmental planning enables cities to prepare their lands and resources to live smarter within the environment, have less need to manipulate the surrounding landscape, and may have better health and comfort from best practise integration.

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index and references

references:Daniels, Tom and Katherine Daniels, The Environmental Planning Handbook. American Planning Association, Chicago, IL. 2003.

Marsh, William M. Landscape Planning : Environmental Applications. Reading, Mass.: Addison-Wesley, 1983.

Mandelker, Daniel R., and Roger A. Cunningham. Planning and Control of Land Development : Cases and Materials. Indianapolis: Bobbs-Merrill Co., 8th Edition, 2011.

Ndubisi, Forster. Ecological Planning : A Historical and Comparative Synthesis. Center Books in Contemporary Landscape Design: Johns Hopkins University Press, 2002.

Randolph, John. Environmental Land Use Planning and Management. Washington D.C. 2004.

Steiner, Frederick R. The Living Landscape : An Ecological Approach to Landscape Planning. New York: McGraw-Hill, 1991.

Muckel, Gary B., Center National Soil Survey, and Service United States. Natural Resources Conservation. Understanding Soil Risks and Hazards : Using Soil Survey to Identify Areas with Risks and Hazards to Human Life and Property. Lincoln, Neb.: USDA-Natural Resources Conservation Service : National Soil Survey Center, 2004.

maP coordinaTe and ProjecTionsCoordinate System: NAD 1983 UTM Zone 12nProjection: Transverse MercatorDatum: North American 1983

Gis sources:University of Arizona - UAir; USGS Seamless Data Warehouse; Multi-Resolution Land Characteristic Consortium (MLRC)

daTed: May 9th, 2012

creaTed by:Daniel Harrison

class:Environmental Spatial Analysis - PLG 580 - Professor Ryan Perkl

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model #1 - siTe sensiTiViTy analysis of The sanTa cruz waTershed model

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model #2 - siTe sensiTiViTy model of The mid Tanque Verde creek basin

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