BYXBEE PARK PALO ALTO LANDFILL CLOSURE GRADING Landscape Design Consultation JANUARY 2007
Byxbee Park Palo Alto Landfi ll Closure Grading Landscape Design Consultation January 2007 Hargreaves Associates Sean Kennedy... Palo Alto Public Works / Operations Ken Haskell... Golder Associates (Engineers) Peter Richards... Artist Michael Oppenheimer...Artist 1
CONTENTS 2
Purpose List of fi gures... 5 Intent of Study... 6 Method of Study... 7 Background Byxbee Park History... 8 Master Plan Design Principles... 9 Study Materials Master Plan... 10 Closure Permit Grading Plan... 12 Drainage Plan... 14 Current Topographical Survey... 16 Recommendations Recommendation 1... 18 Recommendation 2... 20 Recommendation 3... 24 Recommendation 4... 26 Summary Results... 28 Implementation... 29 3
LIST OF FIGURES 4
Figures Figure 1: Master Plan 3D Model... 10 Figure 2: Byxbee Park Plan... 11 Figure 3: Closure Plan 3D Model... 12 Figure 4: City of Palo Alto Landfi ll Plan... 13 Figure 5: Byxbee Landfi ll-park Drainage Plan... 15 Figure 6: Current Survey 3d Model... 16 Figure 7: City of Palo Alto Landfi ll... 17 Figure 8: Master Plan and Closure Plan 3D Model Overview... 18 Figure 9: Master Plan and Closure Plan 3D Models Superimposed... 19 Figure 10: Master Plan 3D Model Closeup... 19 Figure 11: Closure Plan 3D Model Closeup... 19 Figure 12: Master Plan 3D Model Overview... 20 Figure 13: Closure Plan Model and Current Survey Models... 21 Figure 14: Master Plan Model... 21 Figure 15: Master Plan 3D Model Overview... 22 Figure 16: Master Plan 3D Model Closeup with Top of Trash Points... 23 Figure 17: Closure Plan and Survey 3D Models Overview... 24 Figure 18: Survey and Closure Plan 3D Model Superimposed Detail View... 25 Figure 19: Master Plan 3D Model Detail View... 25 Figure 20: Master Plan and Closure Plan 3D Models Overview... 26 Figure 21: Master Plan and Closure Plan 3D Models Detail... 27 Figure 22: Diagram Section of Smoothing... 27 5
INTENT OF STUDY This report provides professional landscape consultation on the closure grading of the Palo Alto landfi ll upon which the future phases of Byxbee Park will be developed. Phase One of the park was constructed upon already completed landfi ll forms and at that time the Byxbee Park design team of landscape architects Hargreaves Associates and artists Peter Richards and Michael Oppenheimer were asked to make suggestions as to the future phases of both the landfi ll forms and the park. Those suggestions were documented and approved in the 1991 Master Plan. Since that time a large majority of the landfi ll closure has taken place. The already closed areas closely conform to the Master Plan grading while the still active areas differ from the Master Plan grading for a variety of reasons. It is the concern of the city of Palo Alto that the completed landfi ll foundation of the park be complementary to the intention of the June 1991 Master Plan update authored by Hargreaves Associates. Therefore Hargreaves Associates was asked to form a study team to review the materials available at this time to determine if the closure grading plan currently being utilized by Palo Alto s Public Works/Operations (PW/OPS) is acceptable. Included in the study team are the original artists from the design team and Ken Haskell, an engineer with Golden Associates. PURPOSE 6
This report is thus an assessment of the landfi ll work done since the completion of the phase one park, the modifi cations that have occurred and any impacts they may have to the future park completion, and contains recommendations both in regards to the landfi ll closure as well as to the next steps now appropriate in the design of the completion of the park. While the Master Plan does include some basic ideas as a framework for the phase two park s completion, it was always intended that at the time of fi nal closure the phase two park s design should move into full services of schematic design, design development and construction drawings. That process is still appropriate, but in addition there are now new opportunities for the park as a result of the landfi ll operations and other changes to facilities adjacent to the park. plans, currently proposed plans and the current existing site, the study team was able to arrive at a series of recommendations. The material presented in this report includes the model images developed for that study. The images illustrate the current conditions and the variables presented by the current closure plan and the Master Plan. The recommendations clarify how the grading fi ts within the goals of the Master Plan design. They also address areas of the site that should receive further attention during fi nal grading in order to fi t within the intention of the closure grading plan. Images used within the recommendations indicate these specifi c areas and clarify aesthetic grading considerations that will facilitate the transition of the landfi ll to a foundation for the completed Byxbee Park. The landscape of Byxbee Park is dependent on the forms created by the operations of the landfi ll. The current landfi ll operations and the fi nal grading of the cap and topsoil that will take place in the next several years will be the basis for Byxbee Park s fi nal development. METHOD OF STUDY Through a process of computer modeling and discussion of the distinguishable differences between previously proposed 7
BYXBEE PARK HISTORY There are two prior reports addressing the development of the Palo Alto landfi ll as Byxbee Park: the 1980 Master Plan for Byxbee Landfi ll Park and the 1991 Byxbee Park Palo Alto Baylands Update. The 1980 Master Plan by Eckbo Kay Associates et. al. provided an initial idea for creating the park. Subsequent changes in landfi ll regulations created requirements for the form and construction of the landfi ll which still have application today. Over time, additional input from the city and community mandated efforts to reduce costs and to integrate the landscape with the Baylands context. The City of Palo Alto Municipal Arts Plan also played a role in the park s development by requiring a public art element and indeed the requirement that the artists would be selected fi rst and then assist in the selection of the landscape architects. The design team was thus assembled to address these components and as led by Hargreaves Associates produced the Byxbee Park Palo Alto Baylands Update in June 1991 which in this report is referred to as the Master Plan. BACKGROUND The Master Plan contains the design documents to construct Phase I and overall plan guidelines for Phase II. Phase I was successfully constructed and has been in public service since that time, enjoying a high degree of use as well as recognition within the design and art world in the form of numerous awards and publications both nationally and internationally. 8
The landscape concepts and plans illustrated in the Master Plan are the starting point for examining any developments as the Phase II effort approaches. This study includes the current analysis necessary to determine if the closure grading plan is acceptable, and to determine any modifi cations necessary both to the closure plan and to the phase two park development. a rich variety of different landscape experiences for the park visitor. The summits and draws also provide varied opportunities for the designers and the artists to locate different artworks and to create habitat variations. This makes the park an exploratory experience as visitors discover art and unique terrain throughout the park all within the context of the subtle colors and textures of the land. MASTER PLAN DESIGN PRINCIPLES The design principles generated in the Master Plan emphasize the inherent qualities of the site: Prospect and Refuge. Prospect is an experience of expansive views from an elevation above the surrounding area while refuge is an experience of protection resulting from a more sheltered environment. The oversized mounding of the land as a result of the landfi ll operation creates high windswept areas with expansive views- Prospect in all directions at this location on the edge of the bay. The leeward sides and the valleys between the landfi lled hills provide Refuge from the breezes that are common to the area. These refuges provide a concentration of environmental diversity for the benefi t of habitat and the experience of park visitors. The variety of landforms created by the landfi ll operations is unique in this area of sloughs and lower elevation bay shore lands. The smaller more intricate hills of Phase I and the larger forms of Phase II provide The fundamental structure for these environmental experiences is the mounding of garbage but the park elements add to these experiences by emphasizing the inherent characteristics of the landfi ll forms for example the windgate in phase one emphasizes one of the more pronounced draws or valleys of the site, while the hillocks atop the landfi ll forms provide points of refuge places to be out of the wind at the highest points of the site. In addition the recreational and art elements of the park are designed to increase awareness of the environment, not only the natural context but the fact of the human intervention the landfi ll as well. Disposal of our refuse is a necessary operation of human society. An operation which in this case is integrated back into our occupied environment as a landscape for recreation and native vegetation and animal life. This juxtaposition of man and nature illustrates the admirable human desire to be a steward of the occupied land, to maximize its benefi ts, and to foster native habitat wherever possible. 9
The original 1988 Master Plan drawing on the right (fi gure 2) and the 3D model on the left (fi g- ure 1) illustrating the original intention for the landforms to be created by operations. This plan was approved by the city of Palo Alto. Figure 1: Master Plan 3d Model MASTER PLAN 10
Figure 2: Byxbee Park Plan, July 1988, Revised Feb. 1989, drawn by Hargreaves Associates. 11
The closure permit plan (fi gure 3) grafts the intended contours for closure (A) onto already completed work (B). The drawing on the right (fi gure 4) was approved by the State of California. B A Figure 3: Closure Plan 3d Model CLOSURE PERMIT GRADING PLAN 12
B A Figure 4: City of Palo Alto Landfi ll Plan, May 2005, drawn by HJW Geospatial Inc. 13
The drainage plan (fi gure 5) was developed separately from the design documents of the Master Plan. It was published in December of 1988 after the Master Plan grading design process. The drainage plan suggested a need for grading changes as areas were measured for drainage, and swales were developed that were not part of the Master Plan s grading scheme. In this drainage plan, it can be seen how the grading for the closure permit plan continued to be developed after the Master Plan. The more sinuous form of the northwest ridge (A) is thus developed in this plan. DRAINAGE PLAN 14
A Figure 5: Byxbee Landfi ll-park Drainage Plan, December 1988, drawn by Mark Thomas & Co. Inc. 15
The current topography of the site (fi gures 6 & 7) shows the windrows and other forms inherent to the landfi ll operations (A). These ares are still to be completed. The completed area (B) of phase II has already fairly closely assumed the form of the Master Plan intention. B A Figure 6: Current Survey 3d Model CURRENT TOPOGRAPHICAL SURVEY 16
B A Figure 7: City of Palo Alto Landfi ll, Photography Date May 2006, drawn by HJW Geospatial Inc. 17
Figure 8: Master plan and closure plan 3d model overview. The most signifi cant recognizable modifi cation to the Master Plan addressed by this report is the change in form of the last phase of the landfi ll. The ridge that now has a more serpentine quality was previously intended as a simple extension of a much larger form in the phase II landscape which presented itself in plan as a simple butterfly form, with smoothed rounded flanks on all sides. Figure 9 shows a combination of the Master Plan overlaid with the permit plan. Figure 10 shows the Master Plan and fi gure 11 shows the permit plan. The essential difference of the permit plan from the Master Plan is that this more complex ridge will change its alignment from north-south to east-west and back again and in the process will create additional drainage valleys. Implementing the Master Plan design principles on this more complex landform means that there will be more opportunities for Refuge. These are places that can become more concentrated with diverse vegetation, have multiple daylight aspects, provide shelter from the wind, and become locations for design elements or artwork. Therefore the net effect of the serpentine form is an enrichment of the park experience. The study team concludes that the sinuous ridge form at the north end of phase II is acceptable. RECOMMENDATION 1 18
Figure 9: Master plan and closure plan 3d models superimposed. Figure 10: Master plan 3d model closeup. Figure 11: Closure plan 3d model closeup. 19
Figure 12: Master plan 3d model overview. Looking more closely at the southwestern corner of the site, the closure permit grading plan in fi gure 13 shows a squaring off (A) of the landform that was not intended by the Master Plan grading (fi gure 14). The red lines show how the ridge and slopes should taper down to a point. We recommend that an effort be made to smooth the form in the fi nal grading so that it resembles the more tapered shape intended by the Master Plan, the current plan, if realized as drawn, will make a more typical landfi ll shape square and abrupt and not in keeping with the context of softly undulating hills. In fi gure 13 the blue represents the current surveyed surface and the yellow shows the extent that the grading permit allows. Therefore the soils currently at (A) can be smoothed down or shifted to the ridge and flank (B) areas without exceeding the limits of the permit plan and will help create a fuller distinct tapered shape. Any additional available soil can also be placed in the (B) areas to help build the tapered shape. The study team recommends smoothing the south west corner to match the original intent of the Master Plan. RECOMMENDATION 2 20
B B A A Figure 13: Closure plan model and current survey model superimposed. Figure 14: Master Plan model. 21
Part of the effort to achieve the Master Plan s desired grading in the southwest corner of the site requires understanding how much can be accomplished in an area that has already been fi lled during landfi ll operations. Figure 15: Master plan 3d model overview. In pursuit of that intent PW/OPS was able to provide Top of Trash elevations in this area which were translated into the models. Discussion with Golder Associates indicates there is some room to achieve the Master Plan design through minor grading efforts while fi nishing this area. Minor excavation of the near surface materials can achieve some of the tapering. Additional fi ll along the ridge and flanks can also help. At locations 12 and 13 the bottom of the exposed red part of the column shows that trash has already been placed above the intent of the Master Plan. Movement of trash to some extent should be considered. The Point 00 marker shows that trash could be placed there and still fi t within the Master Plan grading. The study team recommends moving topsoil and trash to smooth the south west landform to resemble the Master Plan. RECOMMENDATION 2 continued 22
How to read this model view: The blue column shows the position of the surveyed points. The bottom of the column is at elevation 0. The top of the column is elevation 60. The red collar shows the layer of topsoil currently existing at each point. The bottom of the collar indicates Top of Trash. The Master Plan 3d model was then superimposed with a transparency allowing comparison between existing and desired conditions. Where the red collar is above the surface of the Master Plan model means trash has been placed higher than originally desired. Where the collar is below the Master Plan surface is an area where more trash and topsoil could be placed. Figure 16: Master plan 3d model closeup with Top of Trash points Position of surveyed points Trash below expected elevation Trash above expected elevation 23
Figure 17: Closure plan and Survey 3d models overview. Figure 18 shows a combination view of the current topographic survey and the closure plan. Figure 19 shows the Master Plan in the same area of the swale which occurs at the north end and entry point of the park. The swale is the seam between Phase I and Phase II (A). It was not able to be built to the fi nal Master Plan elevations during Phase I. Due to work during Phase II there has been a resultant steep slope leading into the swale. smoothing the ridge back, if top of trash elevations permit. The study team believes that this newly established valley can be a high profi le element of the park. It is within the welcoming area of the park and deserves to receive a high level of fi nish in the closure grading. Its depth and length also provide greater interest and possibility in fi nal design for access, vegetation, and art. This area represents a new opportunity that the future park design development should address. It is recommended that as work continues in the area of (B) that an effort be made to smooth the fi nal form of the north slope to resemble the Master Plan. Also the mouth of the swale could be opened at (C) by The study team recommends that this valley area be smoothly integrated into the remaining Phase II final grading. Monitor grading quality because of the prominence of this area at the park entry. RECOMMENDATION 3 24
A C B Figure 18: Survey and Closure plan 3d model superimposed detail view. Figure 19: Master Plan 3d model detail view. 25
Also the brow of hill which is more visible in the permit plan (A) should be smoothed to match the gentler transitions of the Master Plan. In the opinion of the study team, this can be achieved without the effort of modifying the submitted closure permit grading plan. Figure 20: Master plan and Closure plan 3d models overview. The simple diagram at the bottom (fi gure 22) shows in exaggerated form the crisp transition in black and the proposed smoothing of that transition. It is not uncommon to negotiate this synthesis of engineering and landscape grading plans. The more rigid approach of engineering drafting often benefi ts from some subtle smoothing of the transitions as we are suggesting here. The study team recommends that smoothing of the slope transitions be incorporated into final grading. RECOMMENDATION 4 26
A A A Figure 21: Master plan and Closure plan 3d models detail. Remove topsoil to obtain smooth transition Figure 22: Diagram section of smoothing. 27
RESULTS The four recommendations given will help the fi nal landfi ll form meet the intent of the Master Plan. The study team offers these recommendations because the design goals of the Master Plan were twofold: one) to make the future phases of the landfi ll forms as sympathetic with the Baylands context as possible and two) to create the best possible platform for the future park phases. The recommendations will all work within the permitted closure grading plan. The drainage, trash volume, and boundaries that constrain the closure plan design are intact with the recommendations given. We believe that the operations can proceed as permitted. Monitoring of fi nal grading by PW/OPS will insure these aesthetic refi nements will smooth the transition into the fi nal design and construction phases of the park. SUMMARY The next step is then to realize the implementation of the park elements atop the fi nal landfi ll closure. It will be important to reassess the park elements based on the revisions to the landfi ll forms as there are new opportunities now possible - and the changed context in regards to the needed expansion of parking, and the changes in plans for onsite facilities for recycling and other operations. There are new opportunities because of these changes and as 28
well, there is now the opportunity to flesh out the Master Plan for the remaining park in a process of schematic design refi nement and detailing. This is an opportune time to recommend that for a seamless design between Phase One and Two to be realized, the process of design refi nement and detailing for Phase Two should follow that of Phase One. The future phases of the park can now be reassessed and elaborated upon, ideally by the Master Plan design team, based on these new conditions, the use patterns of phase one, any successes or failures and lessons to be learned from phase one and any new technological or environmental conditions to be addressed. The study team appreciates that this study is allowing the future of the park to be considered at this juncture of closing the landfi ll. IMPLEMENTATION The design ideas of the Master Plan can be implemented on the foundation of the closed landfi ll but need some modifi cations due to changed conditions and new opportunities as outlined above. As the time nears to revisit the park design the recommendations of this report can help prepare the foundation upon which work proceeds. Plan can be implemented as originally envisioned but the study team also believes that there are interesting opportunities in the new convolutions created by the new closure grading plan. The entrance and foreground views and access into the park can be studied and made more prominent in the fi nal design of phase II. Now that the recycling and energy facilities that were part of the original Master Plan are no longer, and there is a need for additional parking there is an opportunity to add to the landscape and features at the north end of the park. And with the success and high use of phase one it is important to add adequate access this newly defi ned north area could afford an opportunity for an additional park entrance. The recommendations in this report and the refi ned design work needed for the park elements will improve the already much appreciated public use of the park. With implementation Byxbee Park will be the amenity originally envisioned by the Master Plan and the City of Palo Alto. Several of the pieces in phase II as identifi ed in the Master 29