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GTE/Re,MP,SPRv-CS 990111BEC<: GILLETT BERGER DEVELOPMENT MANAGER January ll, 1999 Mr. Ga~ Sicb Director of Planning and Community Sendces City of Coppell 255 Parkway Boulevard Coppell, Texas 75019 GTE Shared Services Center 750 Corporate Park Boulevard Coppell, Texas 75019 Proposed Landscaping Revisions As we discussed last week, GTE has had their arborist and ground maintenance personnel review thc completed landscape plans for this project. They have requested several ~visions to the landscape and irrigation design to reduce anticipated problem areas and inaintenange costs, based on their historical experience from other projects they manage in the Metroplex area. Many of GTE's requests pertain to the irrigation system, but some are requesting use of alternate planting materials, due to previous problems they have encountered with thc currently ~ed plant materials, Mesa Design Group ~ ~ewed their recommendations and provided alternate materials and/or methods where applicable. Mesa has ensured that all proposed plant material .alternates or substitutions are ~m .be ~CiW of CoppeH approved plant material list. The plans are currently being revised to reflect these alternates and should be complete by the end of this Week, at which time they will be distributed for bids. In addition, upon receipt two sets of the revised plans will be forwarded to the City for your information and review. One of GTE's prima~y concerns i~ the use of the extensive ground covered area on the Highway 121 berms, and their being able to maintain it in a pre.table fashion. They requested the ability to relocate this ground cover (in identical quantities) to areas around the building and into parking islands, and provide a continuation of the adjacent grass or lawn area over the berms. Also in our discussion, you stated the City will allow a variance to imposed 'water rationing on newly landscaped projects if required, which eliminates another of GTE's major concerns. A copy of the GTE list of concerns and recommendations and the Mesa response letter has been attached for your review and comment. We would like to incorporate GTE's suggestions into the project if possible, however, do not want to go back before the City Council in a formal approval process to do so. Please a_~d~.:se .which of these items '_can be accommodated within the City's admini~vc approVal process, only. r Thank you for your assistance. Encl. Cc.' Will Castro GTE (w/ Enclosures) Joe Dudas PPG (w/ Enclosures) John Bolte JC Bill Millsap Mesa Lonnie Mahoney Beck (w/ Enclosures) BECK Realty Group · 1700PACIFIC AVENUE, SUITE 3800 · DALLAS, TEXAS 752014619 · 214965-1140 FAX 214965-1320 Landscape Desi lq _ nd Maintenance GTE Shared Services Building November 5, 1998 The following notes and observations am based upon a coml:,'ehensive review of the currently, proposed landscaping and imgation plans and written specifications for this site. Observations and comments are listed in no particular order of priority or importance. 1) Formal planting-design - stylized formal landscape designs, with Straight monocultural rows of sirlgle-specJes of trees and shrubJs, are inherently dangerous over the long-term. As the row of trees or shrubs grows and matures, it will become increasingly difficult and expensive to replace damaged or dead plants with similarly-sized specimens. Grouping trees informally - rather than in ordedy rows- alleviates this problem. 2) Oak Wilt susceptibility - Ilas become an important consideration when ,~'hoosing tree species in a landscape design. Live Oak and Shumard Red Oak am both highly susceptible to this devastating fungat disease.. The Texas Forest Service has reported over 200 new Oak Wilt infection centers in the DFW area over the past two years. Cedar Elm might be a cost-effective alternative for the Live Oak trees in the parking lot islands. Bur Oak might be a good alternative for the Red Oaks specified near the building. 3) Bleeding necrosis - is a relatively new disease w~ich cen be devastating to large stands of Sweetgum tr~es in northern Texas, ^ nearby high-profile site in Las Colinas has recently lost several dozen Sweetgum trees to this disease during 1998. Arx~er 50% of the Sweetgurn trees et this site are infected and may require replacement over the next three years. ,,,t,.., ~; ~,-,.: ,.~. ~ ' :', ? 4) Spacing of Chlne~ Pistache - seems too close from a long.term maintenance standpoint. Mature Chinese Pistache trees reach 50 feet in height with 35 to 40 foot canopy spreads. The 20 Pistache trees specified for the entry courtyard on the north side of the building will be approximately 10 to 12 feet apart leading to extreme over~owcling. ., ....- 5) Turfgrass loss due to shading - it appeam that the two Chinese Pistache courtyards on north side of the building will not have enough sunlight to sustain turfgrass growth. ~ ~.~ .... ' ~ ~ · ~,._ i ~, ~ ~ ' ! ' ,, ~g~'ON 1~7*~5--'gGbTE + AS ~(I-]8 ~H SN~I8 SS:O[ GG/IT/[O 6) Rows of Red Oaks - will be planted approximately ten feet from the building. '- ~Tl~e~eS.~e _R~ed 2,a~k_t~_..e~__.~sh. ou? ha.ye mature height? of sixty feet wi~ canopy ~'i;~,'~'__~'__m~'"'~_~.~ ,.or[y~m~..t..eacll..Extreme prun,ng, will be required to avoid ..... ,u~,_,~uee .con~, .c~.. uu,omg mmntenance and window cleaning activities wp, De severmy re~mcted by the close plac~mlent of these trees next to the building. 7) Irrigation bubblers - the real benefit of tree bubbler systems is seen in the f'gst two m' three years following planting, when most Of the trees' root systems are still found in the original tree root ball. It appears that the currently-specified /.. i_l~._~,er_ _sy? .e? may need modification in order to ensure edequete ,oil ball mgm,on. ~s mere some benefit to spec/lying the Tom 6' bubblers? 8) Tree pit backfill - highly-amended backfills for tree planting pits ere nom~ally not recommended on tree planting sites such as this due to soil interface and vmter-movement concerns. 9) Slandpipe depth - one of the benefits of vertical standpipes inserted into tree planting pits is to allow for the removal of standing water during times of large amounts of rainfall. The standpipes, as proposed, will not reach the bottom of the tree plantir~j pit~. lO) 11) Standpipe construction - the bse of 4' ADS perforated ~'ainage pipe with green plastic surface grates - instead of the specified Schedule 40 PVC pipes with threaded fittings - should result in a total savings of over $ 2400.00 in material costs. Shade induced turfgrass loss - With expected mature canopy spreads of forty to fifty feet on each of the two Live Oak trees in each parking lot island bed - it will be very difficult to keep heallhy turfgrass below these trees. Groundcovem would be more appropriate. 12) Increased mowing costs - will be incurred due to the overtime required to mow the parking lot islands during non-business hours. ~90'~N Dwarf Burford Holly hedge - any 3500 foot long single-species, single-width shrub hedge will be extremely difficult to maintain over the long.term Minor variations in irrigation rates, soil textures and nutrienls, and soil drai~;e patterns invariably result in uneven growth and foliar coloration over a few years. Replacement-sized specimen plants also become difficult to find over time. Distinctive groupings of holly shrubs would be more cost-effective to maintain. ~ ,_ ,,~ ,'.-, Whal is the intent of this hedge?l Is it specified for aesthetic masons? Screening reasons? Can it be deleted entirely~ i'. '~ If the holly hedge is to be kept, at least $15,000 could be saved substituting 5-,gallon hollies for the 7-gallon hollies specified. 14) Asian Jasmine encroachment - there does not seem to be a cost-~ffec~ye plan for Keeping the Asian Jasmine out of the Holly hedge. Also, since Asian Jasmine is known to suffer significant amounts of freeze injury in the northern Texas area, has the landscape architect considered utilizing other ~..~. Holly placement unclear - how far from the back-of-curb will the holly hedge be placed_'? It aPL:~ears that the slope angle next to the curb may be as high as 45 degrees. What is planned as a ground cover for areas between the holly and the curb in non-janmine 17) 18) Ezcessive irrigation runoff - how can we avoid excessive runoff in areas where the 8idestrip configuration will be usecI to imgate the burford holly hedge? _ . Shade-induced turfgmss loss - what contingencies are being made for shade- induced turfgrass losses expected under the Red Oak trees near the building? ,,, ~,. Maxlcom compatibility - what would be the additional costs to make the irrigation system Maxicom compatible? lO) Irrigation zone segregation - it appears that varying turf and tree evapo- transpirational demand requirements can be met more efficiently by improving zone segregation design. Irrigation system efficiency ~ it appears that moving a number of valves could result in improved irrigation system performan;e by reducing friction loss due t~ long, dead-end runs. 21) Cost savings on Nellie R. Stevens Holly -approximately $5000.00 could be saved by substituting 5' - 6' B&B Nellie R. Stevens Holly stock for the 45 gallon container stock currently specified. This w~3uld result in very little change in impact or appearance. 22) Mirafi specifiaatione unclear - which grade and porosity-type of Mirafi soil fabric is specified? Will current planting pit design en~ure that soil will not filter into gravel from unprotected aides? Speci~n bees available - up to several dozen specimen-quality Live Oak, Red Oak, and Cedar Elm trees at Ihs Hidden Ridge site are available for transplantation to this site, if desired. 241 8its drainage - no provisions are made for drainage infrastructure. No surface ,.' '/ catch-basins (yard drains) or subsurface drainage is specified. 26) Quick coupler connectiorl~ - the~e does not appear to be art adequate number of quick coupler connectors Situated throughout the site. Irrigation head spacing inconrdsteneies - there appear to be several instances where head spacing on individual lateral lines vary consi(:ierably. 27} Lack of looped mainline - it appears that, as proposed, there will be basically three separate mainline points-of-connection at this site. A single Ioopecl- mainline system with isolation valves '*~)Uid be preferred. Guywire dis;repancy - the drawings call for rubber hose-in-wire guywires. The written specifications call for installation of grommetted fabric guys. W~ich is correct.'? Generator area - it appears that three of the Re~ Oak trees near the ~ ~ ~;~ ~-*~i should be deleted in order to make mom for ~ transformers and an ~ · electrical (Ire'minter. Additional screening shrubbery may be needed, also. ~l~g ~90'0N O~ETC:gGb;~ ~- AS ~gO-~8 ~ SNB£~g SS:O~ GG/I;/Tia