D. Architectural Compatibility Guidelines, Laughlin Air Force Base.pdf

EXECUTIVE SUMMARY

To understand architectural compatibility and how it affects the Air Force, an understanding of the term is necessary.

Compatible is generally defined as “the ability to exist and perform in harmonious combination”. Architectural compatibility results from designing and building facilities in harmony with their natural and man-made surroundings and environment. Architectural compatibility is concerned not only with the physical appearance of buildings, but with site planning, landscape development, security and sustainability.

Military installations should provide efficient and pleasant physical environments conducive to attracting and retaining skilled and motivated personnel. The design, location and maintenance of individual elements such as buildings, roads, parking lots, signs and landscape establish the quality of the environment. Each of the elements should be functional, attractive and harmonious with each other. This helps to create an environment that enhances the capability of the installations to support their mission and fosters pride in and a commitment to military service.

Adoption of these guidelines by base leadership will ensure compliance and result in a homogeneous community fabric that improves overall installation appearance and mission effectiveness.

Specific study objectives include:

• Promote the sense of a unified community by strengthening the prevailing character of the base

• Define goals and objectives leading to more consistency for leadership decision-making

• Provide a view of the base in terms of Visual Districts

• Discuss recommended architectural themes for each Visual

District

EXECUTIVE SUMMARY

1 INTRODUCTION

1.1 Purpose

1.2 Use & Implementation

2 BASE INFORMATION

2.1 Installation Profile

2.1.1 Location

2.1.2 Mission Summary

2.1.3 History of Base

2.2 Local Characteristics

2.2.1 Climate & Weather

2.2.2 Prevailing Architectural Character

2.2.3 Topography

3 ARCHITECTURAL DESIGN GUIDELINES

3.1 Landscape/Site Design

3.1.1 Introduction

3.1.2 Installation Boundaries

3.1.3 Circulation

3.1.4 Open Spaces

3.1.5 Planting

3.1.6 Xeriscaping

3.1.7 Exterior Signs

3.1.8 Site Furniture

3.1.9 Site Lighting

3.1.10 Visual Clutter

3.2 Force Protection

3.3 Sustainable Design

3.4 Building Design Standards

3.4.1 Introduction

3.4.2 Context

3.4.3 Building Siting

3.4.4 Building Form & Mass

3.4.5 Scale

3.4.6 Facades

3.4.7 Roofs & Related Elements

3.4.8 Materials

3.4.9 Texture

3.4.10 Color

3.4.11 Interior Design

3.5 Visual Districts

3.5.1 Introduction

3.5.2 Headquarters and Training District – District 1

3.5.3 Mission Support District – District 2

3.5.4 Flightline District – District 3

3.5.5 Community District – District 4

3.5.6 Student Life District – District 5

3.5.7 Family Housing District – District 6

4 PLANNING AND DESIGN RESOURCES

Architectural Compatibility Guidelines — June. 2006 Page 3 of 76 Laughlin Air Force Base

1.1 PURPOSE

The purpose of the Architectural Compatibility Guide (ACG) is to establish and document installation-specific standards and provide a tool to assure these standards are consistently applied. The ACG strives to recognize the cultural, environmental, climatic and existing facility conditions particular to Laughlin AFB and define the appropriate styles, finishes, and materials to be used to achieve the best facility life-cycle costs and still retain the appropriate environment for people to achieve their highest productivity and efficiency.

• Provide a record of established goals, objectives, and decisions leading to more consistent decisions when a change in installation leadership occurs.

• Improve the environment through the installation’s construction projects.

• Provide a mechanism for environmental design continuity.

• Develop a baseline for review and, if necessary, for changes that may occur as a result of redirection in goals and objectives.

• Establish consistency in installation development which takes into account all elements of the environment.

• Influence design expression. These principles should not be so specific that design freedom is restricted. A designer should have sufficient latitude for creativity.

• Provide clear and consistent communication between the Air Force and designers, whether they are in-house or contracted professionals.

• Improve programming and budgeting by limiting the range of options and promoting consistency.

• Impart a sense of pride, organization, vitality, and good management. The installation should convey the feeling that it is a good place to work and live.

It should reflect a leadership that cares about its people.

1 Introduction

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1.2 USE & IMPLEMENTATION

The ACG is a tool to chart a course towards installation excellence and provides a means to assess the installation’s progress in achieving that end. The ACG is intended to be used at all stages of the facility delivery process from programming through construction, and even operations and maintenance. It is essential that the ACG be provided to the design agent and AE consultants early in the design process to assure that the entire design team understands the applicable design standards and objectives for the project.

The ACG is by no means a stand-alone document. It should always be used in conjunction with the planning and design resources found in chapter 4 of this document to ensure compliance with Base standards and goals.

Implementing a strict design review process is important to ensure the Architectural Compatibility Plan is followed as projects are conceived, designed, and constructed. The flowchart to the left outlines the typical process for ensuring compliance with this guide.

YES

Determine which Visual District the proposed site falls in

Read and understand the requirements of the ACG

Determine the architectural parameters appropriate for that Visual District

Develop conceptual design which addresses the stated objectives for the Visual

District

Submit design to the design review board

Does the design comply with the specific design parameters laid out in the ACG?

Continue to review project for compliance throughout the construction process

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2.1 INSTALLATION PROFILE

2.1.1 LOCATION

Laughlin Air Force Base is located six miles east of the border town of Del Rio, Texas, and about nine miles from the international bridge to Ciudad Acuña, Coahuila, Mexico. It is 150 miles west of San Antonio on U.S. Highway 90. Del Rio has a population of approximately 35,000 and is known as the “Queen City of the Rio Grande”.

2.1.2 MISSION SUMMARY

The 47th Flying Training Wing at Laughlin Air Force Base is one of five Air Education and Training Command pilot training units and conducts specialized undergraduate pilot training for the United States Air Force. Laughlin flew more than 100,000 hours and 64,000 sorties in fiscal year 2004 to achieve its mission. With more than 3,300 people supporting its mission, Laughlin has a significant economic impact on the neighboring city of Del Rio. Everyone at Laughlin is aware of the strong bridges between the base and the Del Rio community.

2.1.3 HISTORY OF BASE

Laughlin is named after 2nd Lt. Jack T. Laughlin, a Del Rio native killed over Java in the South Pacific in the early days of World War II. The base opened in the early 1940s. It was the Army Air Force B-26 training base during the war and was closed in 1947. It reopened during the Korean Conflict as a jet fighter training base.

From the late 1950s until 1963 it was the home of the Strategic Air Command's 4080th Strategic Reconnaissance Wing. A 4080th U-2 pilot from Laughlin discovered Soviet missiles in Cuba in 1962.

Major Rudolf Anderson Jr. of Laughlin was the only combat casualty of the Cuban Missile Crisis who died when his U-2 was shot down over Cuba.

In 1962, the base became an Air Training Command base and its mission for the past 44 years has been to

2 Base Information

Architectural Compatibility Guidelines — June. 2006 Page 6 of 76 train new pilots for the United States Air Force and allied nations. Approximately 400 new military pilots earn their silver wings at Laughlin each year after an intensive 52-week course where they learn to fly using the T-6A Texan II, T-38 C, and T-1A Jayhawk trainers.

The T-6A Texan II is the primary aircraft trainer. It provides a pressurized cockpit and advanced digital instrumentation in a single-engine turboprop. In July 1993, the 47th Flying Training Wing realigned under the newly designated Air Education and Training Command, taking its place under 19th Air Force. Both headquarters are located at Randolph AFB, Texas.

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2.2 LOCAL CHARACTERISTICS

2.2.1 CLIMATE & WEATHER

The climate of Del Rio is semi-arid continental.

Annual precipitation is insufficient for dry farming;

however San Felipe Springs and the Rio Grande provide adequate water for irrigation farming. Over 80 percent of the average annual precipitation occurs from April through October. During this period rainfall is chiefly in the form of showers and thunderstorms, often as heavy downpours resulting in flash flooding. The small amount of precipitation for November through March usually falls as steady light rain, though heavy rains and flash flooding have occurred. Average yearly rainfall is near 19 inches.

Rainfall extremes vary from 4.34 inches in 1956 to

37.75 inches in 1914. Although tornadoes are rare, they have occurred, and have been most often associated with the dissipating tropical storms that have moved inland from the Gulf of Mexico.

Hail occurs in the vicinity of Del Rio about once per year and reaches severe proportions about once every five years. Sleet or snow has been observed in some winters, but frequently melts as it falls. A snowfall heavy enough to blanket the ground only occurs about once every four or five years and seldom remains more than 24 hours.

Temperature averages indicate mild winters and hot summers. Average monthly temperatures vary from the 50s in winter to the 80s in the summer. Cold periods in winter are ushered in by strong dry north and northwest winds known as Northers, and temperature drops of as much as 25 degrees in a few hours are not uncommon. Cold weather periods usually do not last more than several days. The coldest temperature of record was 10 degrees Fahrenheit on December 23, 1989. Temperatures as low as 32 degrees have been recorded as early as October and as late as March. The average occurrence of the earliest freeze in fall is early December, while the average date of the last freeze is occurs in mid to late February.

Hot weather is persistent from late May to mid- September, with most days above 90 degrees.

Temperatures of 100 degrees have been observed as early as March and as late as October. During June, July and August, afternoon highs exceed 90 over 80

Architectural Compatibility Guidelines — June. 2006 Page 8 of 76 percent of the time, while during September they exceed 90 over 60 percent of the time. Being farther away from the Gulf of Mexico and closer to the hot deserts of the Southwest U.S., afternoon highs can get hotter than other places in South Central Texas. Highs of 100 or higher can easily occur on consecutive days.

The wind direction is mostly east and southeast from spring to early fall and then becomes mostly northerly.

In the wake of winter cold fronts, winds can quickly turn to the east and southeast again, before switching to the north with the passage of the next cold front.

Stratus clouds develop late at night and toward the early morning hours as the humidity rises from southeast winds. On some occasions these clouds hang in all day with only a few or no breaks during the late afternoon or early evening. During the winter, these clouds can form easily when moist southeast winds overruns cold air at the surface which produces drizzle and fog. With dry northwest and north winds, usually clear to fair skies prevail.

2.2.2 PREVAILING ARCHITECTURAL CHARACTER

The architectural character of LAFB can generally be described as postmodernist to a point. This is most evident in the construction of some of the newer facilities like the new Wing Headquarters building and Building 246. Del Rio and the surrounding area are rich in design heritage, including the architecture of northern Mexico and historic building in downtown Del Rio. However, there is no predominant architectural theme that has had a significant influence on the architectural style of the base.

Rather than emulating any historic precedent, LAFB has created a unique architectural vocabulary that is predominantly based on the creative use of concrete and concrete masonry. Split-face and fluted concrete masonry units (CMU), exposed aggregate, precast and tilt wall concrete have all been used and these materials are largely responsible for the design continuity evident today.

Buildings at LAFB have generally responded to the local semi-arid and hot climate by limiting the amount of large glass expanses. In some instances, large

Architectural Compatibility Guidelines — June. 2006 Page 9 of 76 overhangs have also been used to respond to these conditions.

2.2.3 TOPOGRAPHY

There is a noticeable change in vegetation from Uvalde to Del Rio. Gentle rolling hills giving way to desert topography and vegetation become increasingly apparent about 20 miles west of Uvalde. West Texas desert country forms the western margin of the Edwards Plateau. It is a limestone terrain.

Between Del Rio and Sanderson is dark gray limestone, which is dissected by the Devils’ River and the Pecos River as they meet with the Rio Grande. The roadbed around Del Rio is on the surface of lower dark gray limestone, which is the same limestone that forms the upper part of the cliffs of Santa Elena Canyon.

On LAFB, the surface topography is generally flat with the major exceptions being drainage swales. LAFB is approximately 1081 feet above sea level and the maximum elevation difference from the highest and lowest point on the installation is approximately 20 feet.

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3.1 LANDSCAPE/SITE DESIGN

3.1.1 INTRODUCTION

Landscaping and site design should provide developed outdoor spaces to promote social interaction and foster a sense of community on the base. Existing features, such as trees, and views should be capitalized on whenever possible.

3.1.2 INSTALLATION BOUNDARIES

The appearance of installation boundaries can be enhanced by providing simple and low maintenance plantings. These plantings can also serve to limit sight lines into the facility, thus improving security.

3.1.3 CIRCULATION

STREETS

While we consider the quality of a base’s facilities of utmost importance, the street system serves as a framework that can either complement or detract from that quality.

Beyond providing a basic mode of circulation for vehicles, streets are an indirect basis of our perception of quality. Installation aesthetics are impacted by many of the elements that make up the vehicular circulation system. These indirect impacts may include pavement surfaces, traffic-related street equipment, street furniture, the actual roadway shapes and the focuses or views that street systems create.

Street Patterns Where an expanded roadway system is under consideration, the street pattern should respond to site conditions and create focal interest. Street alignments that draw one’s eye to significant elements of the base help provide orientation and contextual hints as to one’s location within the base. The circle park at the south end of base with the three streets radiating from it suggests, at least in plan, that Laughlin Drive is the principal street and that important buildings would be located on this street, but they are not.

3 Architectural Design Guidelines

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A properly laid out street system should support uncomplicated movement throughout the base. It can suggest the location of important buildings, entry gates, structures, monuments, etc. Landscape materials used along streets can also aid in advising drivers when making logical progressions from one use area to another.

The main entrance to an installation should represent one of the most carefully crafted components of the base. Accommodating all anticipated traffic including delivery vehicles and pedestrians should be considered in terms of flow and staging. Thematic materials and architectural style can be established by the guardhouse, entry monument, fencing, and other entrance amenities. Overall, the roadway system, beginning with the gate entry, should establish a positive visual image of the installation. At LAFB the approach to the main gate from Highway 90 bespeaks a high level of quality.

Pavers/Other Materials Non-traditional paving materials, such as pavers, may be used at key intersections or adjacent to significant base facilities. These can help notify drivers or pedestrians of an area or location of significance. Use of such materials should be limited to locations of high importance. Material selection should be consistent and limited to one material type and no more than two colors. The selected material must be installed in such a manner that it is able to withstand virtual neglect and constant vehicular abuse. The crosswalk at Liberty Drive in front of the new Wing Headquarters building is a good example of the use of this design element.

WALKS

Walkways define the pedestrian experience on a base.

They are an indicator of quality in the installation infrastructure and of the commitment to ease of circulation. While they are similar to streets in that way, placement and scale are very different and must be addressed in a manner that recognizes the pedestrian perspective.

Sidewalks Consideration should be given to the pattern of pedestrian traffic between buildings when planning sidewalk routes. Sidewalks should be sufficiently wide to comfortably allow two pedestrians to cross paths. Generally, a 6 to 8 foot wide sidewalk is

Architectural Compatibility Guidelines — June. 2006 Page 12 of 76 preferred, but it should never be less than 4 feet wide along secondary streets. Primary sidewalks should be lighted for nighttime safety. Lighting in other areas is recommended.

Placement of sidewalks immediately adjacent to street curbs is discouraged. Instead, a “green zone” between the street and the sidewalk is encouraged where possible. Sidewalks should generally be parallel to the street except when crossing large open areas, where curvilinear sidewalks can create visual interest and provide landscape pocket planting opportunities that enhance the pedestrian experience. This curvilinear pattern would work well at LAFB, connecting activity areas across the many undeveloped areas.

Sidewalks should be located on both sides of a street, especially along main thoroughfares, to afford pedestrians the maximum circulation options and to minimize the need to cross a street to access a sidewalk. The number of curb cuts that occur where sidewalks are located should be kept to a minimum.

Sidewalk materials at major vehicular crossings should signal to drivers that a pedestrian zone is being crossed, and brick or concrete pavers, as previously suggested, are a good option.

Sidewalks should be a part of all new construction projects. Sidewalk configurations should preserve any significant existing landscape. Sidewalks leading to a building should increase in width as they approach a main entrance. Borders of brick or concrete pavers are appropriate at major building entrances and the taupe or camel colors already in use are very appropriate.

Consideration should be given to economical alternatives to gray concrete walks. Among the options are concrete with a small amount of red or brown pigment added, washing the cement matrix away to expose some aggregate and light sandblasting in simple patterns, using a sheet metal template.

Bicycle paths Bicycle transportation is an efficient alternative to traditional vehicular travel and should be given consideration as an integral part of the base circulation system. Bicycle paths can serve as a convenient and safe alternative mode of travel between base facilities that also promote exercise.

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Curvilinear layouts are preferred over linear configurations. Pathways should be sufficiently wide to allow for two-way bicycle traffic to be easily accommodated. Where sidewalks double as bicycle paths, they should be made sufficiently wide to allow comfortable use for both activities and have a designated side for each. When expanding existing facilities, planners should consider building sections of what can become a complete loop of the entire campus.

PARKING

Access to Parking Curb cuts leading into parking areas should use concrete approach aprons to minimize the maintenance associated with vehicular turns on asphalt. Landscape clusters flanking these entrances are encouraged and should be installed at the appropriate setbacks to allow for adequate sightlines for driver. The height of mature plant materials should be considered.

Landscape clusters help to signal the entrance of parking areas and “soften” the increased pavement area associated with curb cuts. A triangular setback of a minimum of 50 feet from the curb must be kept clear of obstacles that can prohibit obstructing a driver’s line of site in either direction of an intersection.

Accessing parking areas from main thoroughfares, especially from the entry roadway, is discouraged. To the extent possible, parking areas should be accessed from secondary roadways in order to minimize the impact on vehicular flow on main thoroughfares where speeds are higher.

Parking Locations The preferred locations for vehicular parking are across the street from a main building entrance or at the side or rear of the building. Buildings should never be viewed from the street across a parking lot.

Where parking in front of a building is required it should be limited to visitor spaces, located so as to not block the view of the building entrance. Vehicular drives within these parking areas should be oriented so that they are perpendicular to the building façade.

Standard parking stalls should have a minimum width of 9.5 feet. Designated handicap parking stalls should be located as close to the accessible entry as possible.

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Force Protection Refer to the section on force protection for information regarding parking and building adjacencies.

Screening/Planting Where dedicated parking across a street from a facility is possible, special care should be taken to set back the parking lot sufficiently to allow for landscape planting opportunities between the lot and the street. The intent of this standoff distance zone is for security, to screen or mask the parking lot from the street and to improve the pedestrian and vehicular views from the street or sidewalks.

This zone can be used to place sidewalks. A minimum of 20 feet from the edge of the street curb to the edge of the parking lot curb should be set aside for this zone. Low berms with low level plantings will completely screen the view of parked cars. The parking area screening at Building 362 is an excellent example and should serve as a model for future projects.

Parking lot medians should be planted with trees, located so that they do not come into contact with overhanging truck bumpers. A goal of shading 20 percent of the parking area with trees at the lot perimeter or medians is not unreasonable.

Pedestrian Considerations Pedestrian walks that lead toward a building entrance should be located within the medians in large parking areas. Texture or material changes should be considered for delineating paths where pedestrians must cross traffic lanes as they traverse the parking lot.

Appropriate ramps at curb approaches to accommodate ADA requirements are to be provided.

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3.1.4 OPEN SPACES

HERITAGE PLAZAS & CEREMONIAL SPACES

When planning future improvements to this important base element, key vistas, axial and spatial relationships and circulation should all be considered. Through art and the landscape, the plaza seeks to convey a sense of the base history and distinguished military accomplishments.

Smaller monuments, landmarks and artworks should be sited and scaled so that they are highly visible yet subordinate to the overall plan and concept of the Plaza. To the extent possible, these should be dispersed, not clustered.

Where seating is to be integrated into the plaza design, it should take advantage of the principal view and be oriented for thermal comfort in both winter and summer. Heritage Plazas should highlight favorable views while screening those that are undesirable.

Berms can be used to define open spaces and emphasize desired views. They can protect the central ceremonial area in the winter while directing prevailing winds into the space in the summer. Berms can also help mitigate traffic noise that could be disruptive during ceremonial events.

The LAFB Heritage Park is a great example of all of these concepts. It is well planned; well designed and executed in quality materials. It is not just an empty formal space, but obviously designed to be used.

RECREATION SPACES

Outdoor recreation offerings enhance quality of life by promoting healthful activities. Open recreational areas must be well conceived and maintained to be successful. Spaces such as parks, playgrounds, baseball fields or other sports fields, gardens, etc. all can serve as recreation sources. These are best located where they are convenient to all base residents and this suggests a somewhat central location. Space in this area should be set aside for future growth of recreational facilities.

SPACES BETWEEN BUILDINGS

Large turf areas near dormitories are encouraged to promote informal recreational activities.

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PLAZAS/COURTYARDS/PATIOS

Plazas and courtyards should be an integral component of the overall base planning effort. When grouping buildings, the spaces between buildings should be as carefully designed as the buildings. Plazas and courtyards should be designed to encourage group gatherings.

Courtyards and patios are typical of the American southwest, though they have not typically been used at LAFB. Inclusion of these in future projects, and development of them in existing areas, is encouraged.

They can be used nine months of the year.

The design of plazas or courtyards should be relatively simple and flexible enough to accommodate a variety of events. Ideally, they can be terminus points for pedestrian walks or other approaches.

Landscape materials used in these spaces should be carefully selected. Trees of sufficient height and width at maturity should be used to ensure that shading of seating areas will be afforded during warmer weather.

Deciduous trees are recommended over evergreens since they allow sunlight and warmth to penetrate the area in the winter months.

Paving material selections should complement the surrounding facilities and take into consideration all drainage requirements implied. Paving patterns or borders in these areas are appropriate, but should be kept relatively simple in design. Divider strips of either brick or concrete pavers are encouraged, as they add interest at relatively little additional cost.

PLAY AREAS

Play areas are an important element of family housing areas, schools, child development and recreational facilities and too often these are placed where space is available, without proper planning. The Consumer Products Safety Commission (CPSC) Handbook for Playground Safety, 1978 and later, provides valuable guidance in the planning of play areas, the design of play equipment and the selection of ground surfacing.

ADA guidelines address design to accommodate children with disabilities.

For active play, a good rule of thumb is 75 square feet per child. Space limitations will dictate how many children can safely use a play area at any one time and

Architectural Compatibility Guidelines — June. 2006 Page 17 of 76 research has shown that accidents increase with overcrowding. The ages of children using the play equipment is particularly important when the range extends from toddlers through pre-teens. Where toddlers are anticipated, the best practice is to develop a separate area to address their needs in order to minimize injuries to these younger children.

The CPSC defines a use zone around each piece of play equipment, consisting of a fall zone and no-encroachment zone. The fall zone is the area around a piece of equipment where a child falling or jumping from the equipment could be expected to land and where impact-absorbing ground surfacing is required.

The no-encroachment zone provides an additional area where children using the equipment can be expected to move about.

Only play equipment that meets the safety requirements established by CPSC should be considered. Safety considerations include entrapment, crush and pinch points, protrusions and edges, multiple exits, guardrails and barriers. The most durable equipment is of steel with a high-performance coating.

Plastics have a shorter life expectancy; wood splinters and is subject to decay.

Selecting play equipment that looks like a rocket ship or castle has adult appeal, but non-thematic structures better support and stimulate dramatic play activities and are more adaptable for informal activity. While bright colors are appropriate there is no evidence that children respond best to primary colors.

The most important component of a play area in terms of reducing injuries is the selection of the ground surfacing material. CPSC establishes impact-absorbing criteria. Positive drainage of the ground surface is essential and play equipment footings must be recessed so that the surface material extends over them. Sand and gravel are undesirable because they do not absorb impact readily. Wood bark decays and, when dry, becomes an airborne irritant. Three types of surfacing material have proven successful.

• Fiber Mulch: This engineered wood product is installed with a depth of 12 inches over a geotextile fabric. The installation requires a network of porous drain lines below the fabric to carry away subsurface water. The mulch is easily worn away in areas of frequent impact

Architectural Compatibility Guidelines — June. 2006 Page 18 of 76 and requires on-going maintenance to maintain a uniform depth.

• Poured-in-Place Rubber Matting: The rubber is poured over a thick bed of loose rubber fill placed over a concrete slab. A substantial edger is required to keep the loose material from migrating.

• Interlocking Rubber Tiles: The tiles, 3 or 4 inches thick, are installed over a concrete slab.

The tiles have short legs that raise them above the slab so that water drains through and is carried away.

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3.1.5 PLANTING/LANDSCAPE

GENERAL

Landscape can be used to direct circulation, provide shade, screen or mask undesirable views, mitigate noise and wind, control erosion, contribute to energy conservation through shading and cooling, establish hierarchical order, emphasize or deemphasize building architecture, define space, improve air and water quality and serve as part of Anti-Terrorism/Force Protection (AT/FP) design.

A landscape theme that takes into account Del Rio’s climatologic patterns, native plant materials, topographic characteristics and the base general plan will set a baseline for future landscape installations.

The use of formal and informal xeriscape clusters base-wide is a very strong landscape concept, providing visual screening between building groupings and its expansion is encouraged.

Limiting landscape specimen installations to those listed on the approved plant list for the Del Rio region is important as it increases the chances for long-term survival of installed materials. The need for supplemental watering and maintenance is greatly reduced. At the design stage, an expectation for a plant specimen’s anticipated timeframe for achieving maturity needs to be realistic so that natural growth patterns are compatible with desired goals.

Screening Landscape materials are an effective method of screening undesirable views of things like storage yards, utility lines or sub-stations, mechanical equipment, electrical transformers, dumpsters, docks and others, when an architectural screening device is unwarranted. When selecting a plant to perform as a screening, be careful to select species that will remain dense close to the ground. The screening at the Fitness Center has already been noted and that at the Visitor’s Quarter (VQ), Building 454, is equally well done.

LAFB, like other installations, incurs substantial cost for landscape maintenance and a lot of this goes toward pruning shrubbery. In selecting new and replacement shrubs, look for species whose growth habit and mature size minimize, or better yet eliminate, the need for pruning. These appear more natural than the pseudo-geometric shapes of pruned

Architectural Compatibility Guidelines — June. 2006 Page 20 of 76 shrubs. Though this is presently not the norm at LAFB, the cost savings will be substantial.

Planting beds of shrubs and flowering plants should be minimized, used only at the main gate, in the Heritage Park and adjacent to principal building entrances.

Elsewhere, the emphasis should be on trees, not shrubs. To reduce weed intrusion, planting beds should be underlain with a mesh fabric and heavily mulched, both at planting and as part of on-going maintenance.

Masking Landscape used to mask views is different from full screening in that the intent is to soften rather than to completely block a view. Applications for masking could be to break up long expanses of fencing or along force protection cable barriers. The intent is to soften the hard lines and to improve visual appeal.

Noise Control Strategic planting of landscape materials can be a good approach for controlling noise and are especially effective when paired with masonry fences or berms.

This application can be particularly useful where buildings or other public spaces are located adjacent to a busy roadway. The most effective installations for noise control will include plant materials with very dense foliage, planted to create a continuous screen and be of sufficient height to moderate noise. It is important to note that plant materials of all heights have the ability to absorb reflected sound. Evergreen plants are preferred when installed for this purpose since their foliage is beneficial for mitigating noise throughout the year.

Shade Providing shade is one of the many benefits of landscape plantings. During the summer, they help to reduce the ambient temperature by a substantial amount to provide comfort and encourage use of outdoor spaces. In the winter, deciduous trees allow light and warmth to penetrate their canopy. The use of deciduous trees around buildings helps to shield them from the full effect of the summer sun while allowing its warmth to penetrate in the winter.

Approximately 75 percent of all heat gain in a building is through windows. The proper use of deciduous shade trees can dramatically reduce the cost of cooling

Architectural Compatibility Guidelines — June. 2006 Page 21 of 76 in the summer and heating in the winter by strategically placing them to shield windows. Tree planting also reduces the amount of turf area which requires significantly more water to maintain.

Shade from trees also improves the ambience of patios and courtyards by extending their usability into summer. They also help to lessen the heat island effect of roadways or parking lots when placed in medians. When planting shade trees on circulation corridors, adequate clearance between the tree and other structures as well as beneath the tree where traffic occurs is critical. The specific growth patterns of a selected species needs to be thoroughly understood in order to avoid future problems.

Definition of Functional Areas The massing of landscape beds and the logical sequencing of landscape patterns can frame views, buffer pedestrians from vehicular traffic and provide separation of distinct activities.

If the intent is to create an atmosphere of order, regular spacing of trees and shrubs is most appropriate.

Formal repetition and contrast to reinforce edges and borders represents the most appropriate application for a sense of coherency. When a formal setting is desired, trees with upright trunk patterns are most appropriate.

Their vertical canopy clearance should be a minimum of seven feet to allow views underneath.

Irregular spacing of landscape materials must be carefully implemented so that there is a sense of overall composition and balance in the final configuration. Informal settings are most appropriate in areas where a diversity of unplanned activities may occur.

Glare Trees, shrubs and other vegetation can effectively reduce glare and reflection when placed between the light source and the observer. This is especially true where reflections from paved areas are being bounced into windows or where sunlight is directly penetrating a window.

Pollution Control The most significant way for landscape to control water pollution is to control erosion. Landscaping can play a very important part in this goal by holding soil

Architectural Compatibility Guidelines — June. 2006 Page 22 of 76 in place and thus reducing the amount of “runoff” during rain events that would otherwise find its way to fresh water sources. Whether runoff events are rapid and dramatic or slow and imperceptible, the materials that storm water comes into contact with are potential sources of pollution.

On steeply sloped terrain where erosion threats are the greatest, planting vigorous ground cover will stabilize the area and mitigate runoff. Planting grass in these areas is discouraged as it proves difficult and even dangerous to maintain. The use of mulch materials helps stabilize soil. This application is highly beneficial to the soil and also helps control weeds that tend to infiltrate planting beds.

The use of river rock as a surfacing material, together with the inclusion of native plant materials, in the drainage swale along Second Street successfully makes a landscape feature of this infrastructure element. Where installing plant materials or loose rock to control erosion is difficult if not impossible, the use of rip-rap is appropriate.

In areas that are mowed, leaving the clippings on the lawn is encouraged. These add nutrients to the soil that in turn reduce the need for fertilization. Clippings also add organic matter to the soil which reduces the amount of runoff.

Landscape & Architecture Landscape materials can be used to emphasize a building’s entry or to mask or screen building walls that lack detail or otherwise detract from the entry.

Formal planting patterns add to the drama created when approaching an important installation facility or important base landmark. This is particularly effective when the landscape helps to frame the entrance of prominent facilities. The use of shade trees along walks and drives, paired with low level ground covers, help to lower the thermal load on adjacent facilities.

In addition to emphasizing the entry, installing plant materials along the foundation of a facility adds to the visual interest of the building by softening hard edges and adding depth to the building façade.

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WALLS

Retaining Walls The primary function of retaining walls is to stabilize soil where elevation changes are severe and where controlling erosion is necessary. They are of most benefit where extensive grading of soil is not possible due to limited area requirements or where excessive grading would be detrimental to the surrounding landscape or roadway system. Where these conditions exist, retaining walls are recommended over extensive grading.

A maximum vertical height of three feet for individual retaining walls is preferred over taller solutions if the specific condition allows. Terracing of battered retaining walls not only creates visual interest and potential seating areas, it also enhances soil stability and keeps individual retaining walls at a manageable scale to facilitate landscape maintenance. They can also be used effectively as a component of force protection.

Using the appropriate masonry material is important.

At LAFB, a concrete masonry unit with a textured ribbed or split face of a color that complements the vernacular taupe or camel colors are appropriate.

Landscape materials can soften the appearance of walls and ensure a fit with the surroundings.

Landscape selections should be made from an approved landscape materials list for the Del Rio area.

Modified drainage patterns created when using retaining walls should be considered during the planning stage.

Landscape Walls Landscape walls are freestanding walls used to screen or mask undesirable views. Their material, texture and color applications should follow the suggestions provided in the retaining wall section. The landscape wall that defines the golf clubhouse site at the circle park, and similar walls elsewhere on base, is done very well. The use of CMU is a continuation of the use of this material at buildings. Cast stone makes the best wall cap, but CMU can also be used so long as it is sloped to keep water out of the porous CMU wall material.

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Equipment Screens Dumpsters and major pieces of mechanical equipment should be completely screened from view. The base preference is for three-sided split-face or ribbed CMU enclosures and LAFB has a good record of uniform screening of dumpsters.

Dumpster enclosures should be sized to accommodate the largest dumpster in use or contemplated for use and ensure that the access side is equipped with a steel gate for full screening. Wall caps should be cast stone or sheet metal and sheet steel should be considered as a backing to steel-framed gates to provide total visual screening.

Mechanical equipment screens are best designed as somewhat taller than the tallest piece of equipment to be screened. Mechanical equipment has a finite lifespan and there is some likelihood that replacement pieces will be taller than the original.

Pieces of equipment like electrical transformers are typically ground-mounted. Simple volumetric forms like these are best left unscreened, painted the standard dark brown color so they visually recede into the background.

LAFB has made use of synthetic rock covers or low level landscape walls to conceal ground-mounted utilities such as backflow preventers. While these treatments “hide” the components in question, they draw unwarranted attention to themselves—appearing unnatural in their setting. If using this method for future screening is desired, grouping these covers with additional natural stones and providing covers that are more consistent with the native stone colors and textures is highly recommended. Alternatively, screening of ground-mounted utilities can be done with planting or, if the equipment is simple in form, it can be left unscreened and painted as noted above.

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Fences Chain link fences are strongly discouraged and wood or metal slats in chain link fencing is not allowed.

Where they are essential for security, vinyl clad chain link material and posts should be used, in a dark green or black color. This should be supplemented with landscape screening wherever possible. There is quite a bit of unscreened galvanized chain link fence at

LAFB.

The preferred design for security fencing is steel or aluminum picket fencing in a dark color, six feet or taller as required for security, with masonry piers 15 to 20 feet on center. Though not intended for security, the fence along Arnold Drive at the golf clubhouse is a good example.

The Rohn fencing used to screen the vehicle yard at Building 131 is very appropriate and well done, particularly supplemented as it is with planting. In certain situations this could also be a security fence.

In undeveloped recreational areas the faux wood fencing, as used along Cactus Lane and Indian Boulevard, is appropriate.

APPROVED TREE SPECIES LIST

The following trees are native and adapted species appropriate for planting at Laughlin AFB. This list may be extended to other tree species pending approval by the Laughlin AFB Tree Board.

Botanical Name Common Name

Pinus eldarica Afghan Pine Cupressus Arizonica Arizona Cypress Taxodium distichum Bald Cypress (Native) Acer grandidentatum Big Tooth Maple (Native) Pyrus calleryana Bradford Pear Quercus macrocarpa Bur Oak (Native) Rhamnus caroliniana Carolina Buckthorn

(Native) Prunus caroliniana Carolina Cherry Laurel Ulmus crassifolia Cedar Elm (Native) Ulmus parvifolia Chinese Elm Pistacia chinensis Chinese Pistache Quercus muhlenbergii Chinquapin Oak (Native) Lagerstroemia indica Crapemyrtle Chilopsis linearis Desert Willow (Native) Sophora affinis Eve’s Necklace (Native)

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Koelrueteria paniculata Goldenrain Tree Quercus virginiana Live Oak (Native) Prosopis glandulosa Mesquite (Native) Ungnadia speciosa Mexican Buckeye

(Native) Prunus mexicana Mexican Plum (Native) Taxodium mucronatum Montezuma Cypress Carya illinoensis Pecan (Native) Ilex deciduas Possumhaw Holly

(Native) Magnolia grandiflora Southern Magnolia

(Native) Sophora secundiflora Texas Mountain Laurel

(Native) Diospyros texana Texas Persimmon (Native) Cercis Canadensis v. texensis Texas Redbud (Native) Platanus occidentalis v. glabrata Texas Sycamore (Native) Sapindus drummondii Western Soapberry

(Native) Ilex vomitoria Yaupon Holly (Native)

3.1.6 XERISCAPING

GENERAL

The word “xeriscape” is derived from the Greek word “xeros”, meaning dry. Xeriscape philosophy embodies landscape principles that apply to any region or climate and challenges landscape designers and those responsible for maintenance to create landscapes that achieve a sense of region in the selection and placement of plant materials while minimizing the use of water.

For Air Force installations, adherence to the principles of xeriscaping reduces water consumption and lowers maintenance costs. Water use for a traditional landscape can be as much as 40 percent of total water use and, though irrigation cannot be eliminated, it can be greatly reduced with the appropriate design techniques and maintenance practices. An attractive appearance need not be sacrificed, as a properly-designed xeriscape can incorporate abundant planting and take on, if desired, even a lush appearance.

Water Budgeting In landscape design, water use zones can be created by concentrating plants with similar water-use requirements. This simplifies both irrigation design and maintenance. There are three typical zones.

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Inner Zone This zone is the smallest, concentrated in areas that are highly visible, like principal building entrances, heritage parks, main gates and functional outdoor spaces like courtyards and patios. The densest planting is reserved for this zone and, in a climate like Del Rio with relatively little rainfall, supplemental irrigation will be required.

Intermediate Zone This transitional zone includes other areas immediately adjacent to buildings, park areas, medians in divided streets and parking lots and strips bordering major streets. In Del Rio a broad variety of plant materials are available for use in this zone that will require regular, but minimal, supplemental watering once the plant materials are established. This can be minimized at streets and parking areas by diverting some runoff from paved areas and around buildings by distributing runoff from roof drains.

Outer Zone The outer zone is everything else. LAFB is exemplary in the manner in which it has treated these areas, with indigenous shrubs and trees that require little to no supplemental water and almost no maintenance.

Turf Areas Turf has the highest water and maintenance requirements of all plantings. The size and location of turf areas should be carefully considered in the inner and intermediate zones. At the inner zone, there will reasonably be some turf areas that suggest a green appearance throughout the growing season, regardless of rainfall, requiring irrigation. These should be minimized. Turf areas in the other zones at LAFB are typically, and appropriately, Bermuda grass or native grasses that brown out in dry periods. In the intermediate zone, efforts should be considered to divert some runoff to turf areas to keep them green.

Soil Improvement Most native and adapted plants in any region do well without soil improvements, but the addition of organic matter to any soil is beneficial. Plants grow better and use water more effectively if organic matter is added.

Further, rainfall will be more readily absorbed by the soil, reducing runoff, erosion and the frequency of supplemental irrigation. Organic matter should be added to the soil in all new plantings in the inner zone and, as feasible, in the intermediate zone as well.

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Irrigation Different soils absorb water at different rates. Slow irrigation allows proper soil moisture to be maintained in the root zone, providing the best growing conditions, while deep watering promotes deeper roots, reducing irrigation requirements. In all but the very hottest weather, one deep soaking a week should suffice. Drip irrigation should be considered for planting beds as there is no loss to evaporation.

Rainwater Harvesting For new construction projects, rainwater collection tanks should…