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ST9301-CS 921015The City With A Beautiful Future October 15, 1992 P.O. Box 478 Coppell, Texas 75019 214-462-0022 Mr. Phillip Westin, P.E. Sver~[rup Corporation 4311 Oak Lawn, Suite 300 Dallas, TX 75219 RE: Sandy Lake Road from MacArthur Blvd. to the East Coppell City Limits Dear Mr. Westin: This letter is written as a follow-up to our meeting of October 8, 1992. During that meeting, I stated that the City of Coppell had several aesthefic/streetscape requirements. With this letter, I am providing several copies from our Streetscape Plan. The main items of concern to the City of Coppell are that the entire intersection of MacArthur and Sandy Lake will be required to have brick pavers and the entry point into Coppeil, west side of the bridge, will be required to have a band of brick pavers. After discussing this with the City Planner, Gary Sieb, my recommendation is that once the preliminary design is complete, a meeting should be scheduled with both myself and Gary Sieb to set down and look at the preliminary plans in relationship to our Streetscape Plan. If you should have any questions concerning this issue, please feel free to give me a call at your convenience. Sincerely, Kenneth M. Griffin, P.E. City Engineer KMG/bd cc: Gary L. Sieb, Director of Planning and Community Services sandyltr Typically, sidewalks will be located one foot from the right-of-way line to allow for all utlities, signage, and streetscape hardware. The planting zone will occur in a 15 foot strip in the required front yard adjacent to the right-of-way line in primary image zones, and in a 10 foot strip in secondary image zones. No parking will be allowed in this zone (Figure 13). While trees are utilized to achieve a more unified appearance on the city's thoroughfares, the major entry points and intersections will be ~key places for providing special identity. Both will rely on special paving and landscaping to create identity, 'and the entry points will contain special monument si§na§e. Edges will also receive special landscape considerations depending on the adjacent land use and development. Thoroughfare Design Major thoroughfares in Coppell have been designated as Primary City Image Zones and Secondary City Image Zones (Figure 2) based on their intensity of use and proposed status in the Thoroughfare Plan. Th6se zones should be top priority for initial streetscape treatment. Primary City Image Zones Denton Tap Road Belt Line Road Sandy Lake Road McArthur Boulevard T hweat Road Secondary City Image Zones Bethel Road Moore Road Freeport Road Parkway Boulevard Each Primary Zone thoroughfare should be a divided thoroughfare with a 15 foot median. Cedar Elms will be the dominant street tree in the median and edges, accented with Redbud and Wild Plum and accent overstory trees of Sweet Gum or Chinese Pistache. Median noses at left turn lanes will be covered with interlocking pavers interspersed by 18" Juniper planting beds. Crape Myrtles above Honeysuckle planting beds will also accent each end of the median (Figure 3). Secondary Zone thoroughfares will have a similar landscape scheme, but medians are not a necessity and the roads should be only of a four lane capacity. If a median is used, Bradford Pear will be the accent tree instead of Crape MYrtle and Liriope will be used for ground cover below the Bradford Pears. Each median for Primary and Secondary Zones will also be accented by Pampass Grass in the transition zone. Pedestrian/bike path crossings at streets will be defined by the red concrete pavers. Intersection Design Intersection designs have been developed for three types of intersections: major, secondary and minor. These three types are identified and located on the Landscape Opportunities map (Figure 2). Major intersections should receive top priority in terms of streetscape implementation. It is proposed that the design of major and secondary intersections have consistent landscape elements to include a 12" high planting bed for annual and perennial flowers, background plantings of pink and white Crape M~a'tles to highlight the bed, and accent overstory trees of Sweet Gum and Chinese Pistache. Crosswalks 15 feet or -8- 12 feet wide should be expressed in red interlocking concrete pavers with light gray concrete pavers delineating the edges of the crosswalks. The pavers will also be used on the corners where pedestrians will be standing. The center of major intersections will potentially be highlighted by a dark gray concrete paver (Figure 4) if engineering proves practical. The third level of intersection design is used to define minor intersections. Crosswalks are eight feet wide and shall be expressed in the red concrete pavers with no edge bandings. Planting beds are not utilized and no special landscaping is required (Figure.5). Edge Design Different land use functions will occur along each thoroughfare creating a variety of physical edges. It is recommended that each of these land use groups be identified by a special landscape theme that will add variety to the streetscape. The land use edges and their respective plantings are as follows: ° * Retail/Entertainment - Crape Myrtles grouped -at entrance and exit openings to help define them, while 30 inch high evergreen shrubs are used to mask parked cars, yet allow visibility to storefronts. · Industrial - Live Oaks soften the edge and provide year .round screening. · Office - Bald Cypress help create identity and provide seasonal color.. · Residential - Red Oaks and Bur Oaks establish a sense of permanence and character while providing seasonal color. Please refer to the typical edge treatments in Figures 3 & 6. The landscape treatments are to be combined with, and not replace, the dominant Cedar Elm street tree plantings. Several existing edges have existing unique streetscape characteristics that need to be enhanced and addressed individually. In each case, Cedar Elms are to be planted to provide for continuity of design. Belt Line/North Lake Edge - The existing park and lake edge should be enhanced by random groupings of Bald Cjq~ress for seasonal color, and Pampass Grass to allow views out to the lake. Existing Cattails at the lake's shore should be preserved, as well as the Mesquite trees in the park. Any sidewalk should be constructed in a serpentine path that reflects the lake's irregular shoreline (Figure 7).' Belt Line/Power Plant Edge - The park like grounds surrounding the power plant could be enhanced by masking the existing chain link fence with flowering vines for seasonal color. Wild Honeysuckle could be the dominant vine with other accent vines giving additional color. Wildflowers could be seeded on the power plant grounds for color, while Pecans planted along Belt Line Road could enframe vistas to the grounds and the power plant itself (Figure 7). Belt Line/St. Louis - Southwestern Railroad Edge - The elevated railroad tracks and trestle located along the northeastern section oF Belt Line Road create a visual and physical edge. The edge could be improved by planting Pecan Trees on the north side of Belt Line in order to mask the elevated track and the berm. The wooden trestles should be left exposed as sculptural elements. However, Flame Leaf Sumac should be planted on the sloped grade by the trestle for color, and Cattails could be planted in the mud flats under the trestle for year round concealment (Figure 8). -9- Sandy Lake Drainage Easement - The existing drainage easement should be converted into a linear park with the following landscape treatments: Cedar Elm plantings continue along Sandy Lake; Bald Cypress are planted through the central portion of the drainage easement but out of the water channel, so as not to impede water flow; the edges of the easement adjacent to residential uses are planted with Red Oaks and · Bur Oaks as suggested above. The drainage spillways are to be masked with concrete pavers or stone to soften their appearance. Sidewalks of a serpentine nature will suggest a more parklike atmosphere (Figure 8). Entry Point Design The identi~ty of Coppell~ can be further defined by creating entry point features at the major and secondary entrances into the City. Ultimately, there should be eight major entry points into the City occurring at the following municipal boundary lines: Belt Line Road (south) McArthur Boulevard (south) Belt Line Road (east) Sandy Lake Road (east) McArthur Boulevard (north) Denton Tap Road (north) Thweat Road (west) Bethel Road (west)' Several secondary entry points, such as the proposed Freeport Road at the southern boundary, could be developed. Entry points are designed to create a sense of arrival in the City, both visually'and texturally. For major entry points, a twenty foot band or crosswalk of red concrete pavers stretches across the street, creating a visual and textural sense of arrival. The crosswalk is further defined by two bands of light gray concrete pavePs on both edges. The crosswalks terminate at two triangular planting beds, one on each sideof the street for annuals and perennials (Figures 9-11). A City monument entry sign is placed behind the planter bed on one of the street sides (location depends on boundary line). Both planter beds are enframed by Crape Myrtles for color, and Sweet Gums or Chinese Pistache as accent overstory trees. The entry monument is of a traditional design (Figure 12). Medians at all entry points will receive special treatment in that the nose will be covered with red concrete pavers and a 10' by 10' planting bed. Crape Myrtles will be planted in the median behind the planting bed (Figures 9-11). Secondary entry points will have a 15' crosswalk with one band of pavers defining each edge. The monument sign will be smaller in scale and a median will probably not be in the thoroughfare. The landscape scheme should be similar to those at major entry points (Figure 11). -10- Street Hardware and Special Landscape Elements The term "street hardware" refers to the man-made elements found within or adjacent to the street right of way. These include pavers, street lights, traffic signals, telephone/electric poles, and traffic signage. Benches and street furniture have not been included in this study. Pavers The city standard paver for use at intersections, City entry points, at Uevelopment/ subdivision entry features and to delineate all pedestrian/bike path crossings of streets will be the interlocking paver "Uni-decor" manufactured by Pavestone (or its equal). Antique red shall be the standard color, although dark gray pavers will be used for centers of intersections and a light gray will be used for accent banding. Accent banding will be accomplished using 4" by 8" rectangular paver, "Holland Stone" (o~,, equal). All pavers are + 2-1/2" thick pigmented concrete pavers set on a sand leveling bed. The s~bbase will be reinforced concrete paving, unless another material is approved by the City Engineer. Alternate paving materials at subdivision/development entry shall be .acceptable if they are comparable in color, quality and texture to the City standard. Street Lights Research into the possibilities of recommending a traditional fixture to TeXas Power and Light for use in the street right of way indicated that the chances for approval by TP & L were extremely slim. Without TP & L approval for a particular fixture, the City would be responsible for providing, maintaining, and financing the electric usage of these non-standard fixtures. The 20' and 30' KIM fixtures, presently required by the City and provided by TP & L, are therefore recommended as the best alternative for public street lighting. Their simple design and dark brown duranodic finish are compatible with most architectural styles and land use. The more traditional light fixtures would be appropriate for individual projects/developments. The property owner/developer would then be responsible for installing, m~intaining and paying for the electric use for these traditional fixtures. Traffic Signals The recommended traffic signal design (Figure 16) was selected to be compatible with the approved City street lights. Both are simple in shape, structurally stable and can be finished in dark brown duranodic or black to match the approved City street'lights. Telephone and Electric Poles As evidenced by the Subdivision Ordinance, the city intends to limit the presence of telephone, power and television cable along the street edge. Either underground or rear alley access lines are to be established in alt developments. Where alley access lines cross side streets, the City Engineer has recommended to TP & L that simply designed metal support poles be used and set back from the street to minimize any view of the poles/wires. It is also recom~nded that the metal poles be painted to match the finish on the approved City street lights. -12- Regulatory (Traffic) Signage The basis for the design concept for regulatory signage is the improvement of its appearance over that of the existing unsightly standard of mounting a sign on a galvanized post. Figures 17 and 18 show the recommended regulatory sign standard for Coppell. The single pole alternative (Figure 17) represents the typical city standard, while the double pole sign is to be used where appropriate along major thoroughfares. In both instances, the poles are to be two (2) inch square steel posts painted to match the finish on the City street lights. The backs of all signs are to be painted to match the posts. It is also recommended that the street signs in Coppell be redesigned to reflect the desired traditional character of the city. This can be accomplished through the use of a more traditional style of lettering (with a serif) done on a background which matches (but is .lighter than) the dark finish on the pole. It would be our recommendation that such a sign be done at the same time that a new city logo is considered, so that the lettering style on the street sign is consistent with the logo. Automobile Screenin~ One of the key elements of the streetscape design is the visual screening of the fronts of automobiles parked adjacent to the right-of-way along primary and secondary image zones. Figure 19 depicts two different alternatives for accomplishing this objective. In both instances, the primary screening element is a minimum of thirty (30) inches high measured from the botton of the curb at the front tire of the automobile. Precast panels covered with ivy, bnick walls, and grass covered earth berms are all acceptable screening alternatives. Screening Walls All required screening walls along primary and secondary image zones are to be constructed of brick; the height shall be no less than six (6) feet nor more than eight (8) feet in height, and all walls shall be constructed with a structural concrete foundation. As depicted in Figure 20, the wall shall be detailed so that columns are expressed typically at thirty (30) feet on centers. The texture or plane of the brick shall be changed at the top of the wall .to provide additional variety. Cast stone can be used at the top as an alternative cap. Ironwork can be~incorporated into the design of screening walls as long as the view beyond is appropriately landscaped and is not a view of the rear yards or fences of housing. Sidewalks at screening walls shall be constructed adjacent to the curb and shall be no less than five (5) feet in width. However, sidewalk placement may vary to ensure pedestrian safety. A serpentine sidewalk may be appropriate if placement of the walk creates large enough pockets of greenspace for landscaping. Landscaping in the form of shrubs and trees shall be planted in the area between the.screening wall and the sidewalk so that a minimum of fifteen (15) percent of the wall is obscured by planting. Trees shall be planted at the same minimum density as would be required for non-residential uses. Landscaping shall be planted so as to minimize future conflicts with subsurface utilities. The developer who subdivides the lots adjacent to the wall shall construct the wall and install the landscaping and an acceptable sprinkler system. He shall also create the mechanism for an owners association to be responsible for maintenance of the wall and landscaping. -13- Open Draina~ewass Figures 21, 22 and 23 depict landscaping concepts to be considered for incorporation into the engineering design of open drainage areas. The primary area of concern relates to those sections of the drainageways which are visible from primary and secondary image zones, within ~one hundred feet (100') of the R.O.W. The pedestrian/bike path shown should be included if the drainageway fits into the approved City Hike/Bike Trail Plan. Key aspects of concepts are the 'installation of a sprinkler system in the landscaped portion drainageway by the developer and the creation of an owner's association to assume overall responsibility for maintenance of the landscaping. Trees are to be requred along each side of the drainageway at a ~inimum density of one for every forty (40) feet of frontage. Headwall Figure 24 depicts a headwall for a culvert along an open drainage swale adjacent to a roadway. This detail is particularly more important where curb and guttering will not be installed for several years. The intent is to provide an attractive headwall design over which a mower can be driven or pulled. Stone, brick or concrete pavers are acceptable materials covering the headwall, although the previously mentioned "Uni-decor" concrete pavers (antique red) would be the most desirable alternative. The facing would only be appropriate for permanent headwalls that are visible from primary or secondary image zones (within 100' of the R.O.W.). The requirements for facings for culverts should apply both to pipe culverts and box culverts. Landscape Maintenance The City of Coppell will be responsible for all median maintenance, all paving maintenance, and the repair of streetscape elements when damaged by City initiated 'utility work in dedicated easements. Other damage to streetscape elements occurring during utility repairs will ]be the responsibility of the utility company. The established owners associations or individual property owners will be responsible for the maintenance of streetscape elements in the parkway and the fifteen (15) feet nO,parking zone adjacent to the parkway. This will include residential brick screening walTs and landscaping in common areas. An Owner's Agreement (see attached Exhibit A) wil~ be approved during the subdivision plat process and filed with the City. ~ It formally establishes the owners association, defines the areas of maintenance, and provides the City with the ability to assess the association if maintenance responsibilities are not carried out. -14- IIII! m,w~r ~ ~ ~ IIIIII f:~$~n~ r.,rn' ~ z~ LAH D~::~TAP~ OPPORTUItlTI~5 CITV OF COPPELL , TE#GS ~ INT~~TION I I ............ ~!1!!!!!!!!!!!!! !!!!!!!!!!!!~lll!!!!!!ll!l!!!! ................. F O* 10' 20' /VNAdOR ENTRY POINT~ F-J_i- 40' 80' i~LL STREETSCAPE STUDY [,. EEl:Il ARCHITECTS, INC. Figure 10 ENTRT/~ONU/~I~T 516N COPPELL STREETSCAPE STUDY Flgur® 12