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HomeMy WebLinkAboutEast Vail Conceptual Alternatives Report v3.pdf 1-70 East Vail Landscape and Water Quality Improvements Conceptual Alternatives Report :, Tr � h - Y'!',1-4.2.0.4' ..0 '+k #4 `r ri t. i{y. Y r r� '1 �"'• i,*, Ra•']r h :* • : te. ... ` 41. - Berl"+ r�r.-'- ' .- . +/_.4 _- k. .,, . rY___--!-4.4.-, Y_ � � „it,' `� : . -4 i- ., —�... ,-ti mes F- y I "—x_z .4r r'[L.� ..}Tx' .4 !j*. f V _ -- '_ .- r * l �� 4y�� • �21.ry�rr L. - {� -s _ }r4. ,ice' -;^j-. ;tom - '. ..Y { - Vit' #• �*- - a_ . } .,� nFas� � JK ••,- -... + I- til _r A"yf • - _ . , .•-•,:e10.4,' _ o, • 0 . _ ,_. l ' • Prepared for Town of Vail, Colorado July 8, 2016 Prepared by: With support from: MUNDUS BISHOP WATER & NATURAL RESOURCES 720 S. Colorado Boulevard, Suite 410 S 2601 Blake Street, &lite 300 Denver, Colorado 80246 Denver, Colorado 80205 Phone: 303-757-3655 Phone: 303.477.5244 www.respec.com httri://www.mundusbishop.com/ Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Table of Contents 1 BACKGROUND AND PURPOSE 1 2 SITE CONSIDERATIONS AND CONSTRAINTS 2 2.1 Maintenance 2 2.2 CDOT Requirements 3 2.3 Landscape Aesthetics 3 2.4 Existing Utilities 3 2.5 Water Rights 4 3 WATER QUALITY DESIGN ELEMENTS 4 3.1 Check Dams 4 3.2 Sump Inlets 5 3.3 Sediment Vault 5 3.4 Surface Sediment Basin 5 3.5 Proprietary Treatment Structures 6 3.6 Infiltration Basins 6 3.7 Wetland Polishing 6 3.8 Sweeper Bays 7 4 EXIT 180 LANDSCAPE AND WATER QUALITY 7 4.1 Landscape Approach 7 4.2 Existing Exit 180 Landscape Conditions 8 4.3 Proposed Landscape Concept 11 4.4 Plant and Materials Palette 14 4.5 Exit 180 Water Quality Concepts 15 4.5.1 Retrofit of the Existing Storm Sewer System 15 4.5.2 Wetland Polishing 16 4.5.3 Check Dams 17 4.5.4 Concrete Sweeper Bays and Pans 17 4.6 Water Quality Treatment Train 17 5 SNOW CAST OFF AREA 19 6 TRUCK RAMP SITE 21 7 CONCEPTUAL COSTS 22 8 REFERENCES 23 TABLES& FIGURES Figure 1 — Vicinity Map Figure 2 — Example Check Dams Figure 3 — Example Sediment Vault Figure 4 — Example Surface Sediment Basin Figure 5 — Exit 180 Aerial Figure 6 — Exit 180 Existing Condition Figure 7 — Exit 180 Existing Vegetation Prepared by RESPEC, Inc. TOC Page 1 of 2 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Figure 8 — Exit 180 Existing Conditions at Southeast Corner Figure 9 — Exit 180 Proposed Concept Figure 10 — Existing Topographical Character Figure 11 — Northwest Corner Exit 180 Proposed Concept Figure 12 — Southeast Corner Exit 180 Proposed Concept Figure 13 — Plant Palette Samples Figure 14 — Materials Palette Samples Figure 15 — Stone-Lined Inlet Concept Figure 16 — Exit 180 Water Quality Flow Diagram Figure 17 — Snow Cast Off Area Aerial Figure 18 — Snow Cast Off Area Low Water Crossing Location Figure 19 — Truck Ramp Site Aerial Table 1 — Conceptual Costs APPENDICES Appendix A — Appendix A of the Gore Creek Water Quality Improvement Plan Appendix B — Gore Creek Action Plan Stormwater Control Projects Appendix C — Existing Site Photos Prepared by RESPEC, Inc. TOC Page 2 of 2 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements 1 BACKGROUND AND PURPOSE The purpose of this report is to document the development of conceptual alternatives for the 1-70 East Vail Landscape and Water Quality Improvements project. The recommendation, location citing, and initial concept for the proposed water quality improvements included in this project were first provided in Appendix A of the Gore Creek Water Quality Improvement Plan, completed in August of 2013 by Leonard Rice Engineers, Inc., although Appendix A itself was authored by Alpine Engineering, Inc. in September of 2012.The applicable portion of Appendix A of the Gore Creek Water Quality Improvement Plan is included as Appendix A herein. The proposed improvements were further developed in the Gore Creek Action Plan Stormwater Control Projects, completed in May of 2015 by Alpine Engineering, Inc. The applicable pages of this document are included as Appendix B herein. The Town of Vail was awarded funding for the water quality improvements included in this project through the Transportation Alternatives Program (TAP). The goal of the improvements is to address the 303(d) impairment for aquatic life along Gore Creek that exists from its confluence with Black Gore Creek near the bridges at milepost (MP) 181.9 of 1-70 all the way to its confluence with the Eagle River. The 303(d) impairment for aquatic life along Gore Creek is provisional, which means the specific cause of the impairment is unknown. The three individual project locations are along 1-70, generally between MP 179.8 and 182. Their specific locations are noted by red polygons in Figure 1 below. The three project sites are named by this report as the Exit 180 site (Exit 180), the snow cast off area under the bridges at MP 181.9 (snow cast off area), and the base of the runaway trunk ramp (truck ramp site). Existing conditions at each of the sites are documented in Appendix C. Figure 1—Vicinity Map • • MP"1.8U. Exit 180 . - = • The conceptual design alternatives included in this report have been developed to improve stormwater quality runoff from the Exit 180 site and from the snow cast off area and truck ramp site near MP 181.9. The alternatives at the Exit 180 interchange also include landscape improvements. The water quality alternatives developed in this report include various sediment collection and/or infiltration Prepared by RESPEC, Inc. Page 1 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements opportunities at each of the three sites. The concepts chosen by the Town of Vail will ultimately be fully developed in accordance Town of Vail standards,AASHTO design standards, and CDOT standards. 2 SITE CONSIDERATIONS AND CONSTRAINTS There are three individual sites included in the 1-70 East Vail Landscape and Water Quality Improvements project and each presents its own unique list of constraints that need to be incorporated into the design of the improvements. Additionally, some of the design goals for each site could be considered mutually exclusive with each other. For example, when a project proceeds with a focus only on making maintenance as quick, simple, and low-cost as possible, the final design may not provide as much water quality or aesthetic benefit. On the other hand, when a project proceeds with a focus only on aesthetic benefit, maintenance may be unreasonably time consuming and costly. Additionally, because each of the three sites is located within CDOT right-of-way, CDOT must ultimately approve the design of each site. This section of the report discusses the multiple expectations for each site that must be balanced to maximize the benefit each site can provide. Each site will be discussed individually and in more detail later in this report with regard to the considerations and constraints listed in this section. 2.1 Maintenance There are two major considerations when it comes to maintenance. The first is maintenance of the water quality facilities themselves. This consideration applies to each of the three sites. It is imperative that water quality facilities be maintained properly as they will not function if they are not maintained. Maintenance activities will require the use of a vac truck, at a minimum, and may require periodic excavation and replacement of infiltration materials and/or vegetation if infiltration is selected as one of the design concepts to pursue for final design. Maintenance activities for improvements proposed by this project, including maintenance of landscape areas and irrigation systems, will require additional maintenance funding. Maintenance will also require that adequate access be provided to each of the water quality components that need to be maintained. Access roads and ramps must be able to accommodate the size and weight of the equipment needed to maintain the facility. The second major maintenance consideration is snow removal and storage operations. Although this consideration applies only to the Exit 180 site, the Town of Vail will likely be required to acquire additional snow removal equipment and hire additional snow removal personnel if the proposed improvements require a significant change to current snow removal and storage operations. Town of Vail maintenance personnel have been consulted as part of the conceptual alternatives analysis to understand current snow removal and storage operations and potential constraints. Depending on the design elements and configuration selected at the Exit 180 site, additional maintenance costs may occur if additional hauling of snow in the winter is required. Town staff should be consulted to quantify additional anticipated maintenance costs, as they are not included in the estimate in this report. The current understanding between the Town of Vail and CDOT is that CDOT maintenance crews are likely willing to consider maintenance responsibilities for the water quality facilities at each of the three sites, but the full scope of the maintenance activities has not yet been determined. While CDOT is likely to agree to perform sediment removal at sump inlets or sediment vaults, CDOT may not agree to accept responsibility for the removal and replacement of infiltration media or maintenance of landscaping materials or vegetation that could surround the water quality facilities at the Exit 180 site. Once the Prepared by RESPEC, Inc. Page 2 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements design has been fully accepted by CDOT at the FOR meeting, it is anticipated that an intergovernmental agreement (IGA) or a memorandum of understanding (MOU) will be developed to assign maintenance responsibilities for the proposed improvements. 2.2 CDOT Requirements CDOT requirements for the snow cast off area under the bridges at MP 181.9 and the base of the runaway trunk ramp are essentially limited to the maintenance considerations described above, although improvements in the median and outside of the eastbound lane of 1-70 at the truck ramp site may require guardrail because of clear zone criteria. However, improvements at the Exit 180 site must also meet a myriad of CDOT roadway design criteria. The RESPEC team has had several meetings with CDOT representatives regarding potential alternatives at the Exit 180 site. CDOT's concerns include site distance, z slope criteria,the potential for ponded water or other obstructions within the clear zone, and the time required to maintain the facilities. Representatives from CDOT's various program areas including utilities, hydraulics, traffic, maintenance, environmental, and materials, among others, will have input into the final design at the FIR and FOR stages of the project. 2.3 Landscape Aesthetics The three sites included in the 1-70 East Vail Landscape and Water Quality Improvements project can be separated into two general categories, those that include an aesthetic landscaping component and those that will simply be revegetated. The Exit 180 site is the only one of the three sites that will receive landscaping. The snow cast off area under the bridges at MP 181.9 and the base of the runaway trunk ramp are simply to be revegetated once construction of the water quality facilities is complete. Providing water quality treatment and landscaping elements at the same site can sometimes result in conflicts between the proponents of the two functions when the desire for what would be perfect for one function is placed ahead of what would be most practical for both functions. While a site can be designed with aesthetics as a high priority, the design has to account for changes to site conditions over time and the need for maintenance. When landscaping is located in the immediate vicinity of a water quality facility, especially one that is expected to collect a very large amount of sediment, consideration has to be given to the viability of the landscape aesthetic not only immediately following the establishment of vegetation, but as sediment and other pollutants accumulate at the site over time. Frequent maintenance may be able to alleviate the situation, but the frequency required may be more than what is economically feasible or practical. If the incoming sediment load is disregarded during the design of the landscaping, the site will not end up with the desired aesthetic. Vegetative elements of the landscape design should not be located where heavy sediment is expected to accumulate. Conversely, the areas where sediment is expected to accumulate should ideally be comprised of materials from which the sediment is easily removed if maintenance staffing and/or budgets are not able to accommodate labor-and time-intensive sediment removal activities. 2.4 Existing Utilities The Exit 180 site has an extensive amount of utilities including water, sanitary, electric, fiber optic, telephone, and storm sewer. There may be others not yet identified. The existing storm sewer lines will be an integral part of the water quality improvements, as they will continue to convey runoff from inlet to inlet, ultimately discharging to Gore Creek. The snow cast off area does not appear to have any Prepared by RESPEC, Inc. Page 3 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements utilities and the truck ramp site likely only includes CDOT's large fiber optic line that runs the length of I- 70.The intent of the design of each site will be to avoid all existing utilities to the extent possible. 2.5 Water Rights Colorado water law does not allow for water quality facilities to permanently pond water. Water quality facilities must be designed to continuously release or infiltrate at least 97% of runoff from a 5-year storm within 72 hours after the end of the rainfall event.They must be designed to continuously release or infiltrate runoff from events greater than a 5-year storm as quickly as practicable. In no event may they hold water longer than 120 hours. 3 WATER QUALITY DESIGN ELEMENTS This section will discuss several general options that can be utilized at one or more of the three project sites. It will also discuss general pros and cons to each in terms of water quality treatment, aesthetics, and maintenance requirements. 3.1 Check Dams Check dams are small berms placed across drainage swales to slow the velocity of runoff in those swales. This allows sediment to fall out and provides an opportunity for suspended or dissolved pollutants to infiltrate into the soil or be absorbed by local vegetation. Check dams are designed to overflow during larger storm events. Sediment should be removed once it reaches half the height of the berm. Check dams can be also developed as landscape form elements that incorporate plantings to provide an aesthetic benefit in addition to a water quality benefit. Figure 2 shows a few examples of a check dams that contribute to the landscape aesthetic. Figure 2—Example Check Dams At . :4:lia '' ^• id'. �' '� _ ,�Y;: ,1.:' ^.1?. .moi, , �.,yr V ,, '. j ':' ,` ' .. �E•• '•}rte .�::K�� W-. {: r /�.:..: - s. z'..1.P ., ` .4•' The manner in which a check dam is cleaned and maintained is dependent upon the materials used to line the upstream invert of the swale. A vac truck can typically be used in all cases. If needed, a small drainage pipe can be placed through the berm to allow the area upstream of the check dam to drain more quickly. Check dams will become overrun by sediment without proper maintenance. Prepared by RESPEC, Inc. Page 4 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements 3.2 Sump Inlets Sump inlets are simply storm inlets that have an inlet bottom a foot or more beneath the lowest storm sewer invert out of the inlet. The volume beneath the lowest invert out of the inlet is designed to capture and store sediment. The deeper the bottom of the sump below the lowest storm sewer invert out, the more sediment can be captured and stored in the sump. Sump inlets can be cleaned with a vac truck. The only disadvantage to sump inlets is that water may pond in the sediment storage area, and ponded water is frequently considered a public nuisance. It is possible this can be somewhat mitigated by including small holes in the sides and bottom of the structure and backfilling around the structure with course gravel to allow the stored water to drain. The frequency at which each sump inlet requires maintenance can be determined through monthly inspection over the course of the first year each sump inlet is in service. 3.3 Sediment Vault Sediment vaults are similar to sump inlets in that they have a storage volume beneath the invert out of the structure. Sediment vaults are typically larger than sump inlets and can include baffles, walls, weirs, screens, and orifices that trap sediment and floating debris. Large sediment vaults can be expensive to construct and may require multiple access hatches or grates so that they may be easily cleaned with a vac truck. They will also pond water beneath the outlet, although this ponding may be reduced by including small holes in the sides and bottom of the vault and backfilling it with coarse gravel to allow it to drain. The frequency at which each sediment vault requires maintenance can be determined through monthly inspection over the course of the first year each vault is in service. Figure 3 shows an example of a sediment vault. Figure 3—Example Sediment Vault ' 4 ifo • 3.4 Surface Sediment Basin A surface sediment basin serves as a collection point for sediment and is accessible by a vehicle. Maintenance crews can drive into a surface sediment basin and collect sediment with a front loader. It typically has three walls against which a loader or skid steer can push and scoop sediment. Figure 4 shows an example of a large surface sediment basin during construction and full of sediment. The frequency at which each surface sediment basin requires maintenance can be determined through monthly inspection over the course of the first year it is in service Prepared by RESPEC, Inc. Page 5 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Figure 4—Example Surface Sediment Basin ,,. l J - •tet^� _.� K5 _.w^^ - - - _-�3_ • t 3.5 Proprietary Treatment Structures Proprietary treatment structures are underground treatment facilities that are manufactured by various companies including Contech, Oldcastle, and AquaShield, among others. These structures often use hydrodynamic separation to remove coarse sediment. They may also contain cartridges that can remove dissolved pollutants. They are an excellent option where space is very limited, flow rates are very small, and inspection can be provided regularly. They are also relatively expensive to purchase and may become quickly overwhelmed by large amounts of sediment. They may also require some form of filter cartridge that may need replacing on a regular basis, adding to maintenance costs. 3.6 Infiltration Basins Infiltration basins are depressions designed to store runoff on the surface and infiltrate it gradually into the ground. They may be vegetated or not and are dry except in periods of heavy rainfall. They can be very effective at removing pollutants by filtering runoff through the soils and they are easy to construct. However, they are also prone to fail without frequent maintenance or if runoff is not pretreated prior to reaching the infiltration basin. If an infiltration basin is vegetated and the basin fills up with large sediment, the vegetation will most likely be destroyed during sediment removal operations. If an infiltration basin is lined with decorative cobble, the cobble will likely have to be removed and replaced during sediment removal operations. In either case, maintenance requirements of infiltration basins are typically extensive if peak performance is desired. If they are not maintained with proper frequency,they often become unsightly. 3.7 Wetland Polishing Wetland polishing consists of discharging runoff that has already had the majority of sediment removed into an area populated with wetland plantings. The water is allowed to spread out over the wetland polishing area and the wetland plants treat the water quality by trapping the remaining sediment and retaining excess nutrients and other pollutants such as heavy metals. If the great majority of sediment is not removed prior to runoff entering the wetland polishing area,the wetland can quickly become buried in sediment, depending on the sediment load in the runoff. Wetland polishing areas need to be designed to receive minimal sediment so that maintenance activities that could destroy the wetland plants can be limited. Prepared by RESPEC, Inc. Page 6 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements 3.8 Sweeper Bays Sweeper bays and concrete pans are roadside facilities that allow sediment to accumulate where it can be easily cleaned with a street sweeper. Sweeper bays and concrete pans are an alternative to soft shoulders that often allow sediment to mix with native soils, making it difficult to remove the sediment without removing the native soils. 4 EXIT 180 LANDSCAPE AND WATER QUALITY This section will discuss landscaping and water quality concepts at Exit 180. It will discuss optional features as well as how these concepts can be developed to facilitate maintenance and meet CDOT roadway criteria. An overall aerial of the Exit 180 site is shown in Figure 5 below. Figure 5—Exit 180 Aerial k .. � y ` s.� r ;4� a : e r ur!,- ,-,.-4'.;,•4'.. v y �."" _ _ q :'� f . �ryu ' "! r , ��. a�% � t� �� '�I * -! IX� rte + ,� � -- .: �� w ��� +rte J -• r I „ .n.{ a �I -- 4.1 Landscape Approach The Vail Valley is an exceptional natural landscape. Its alpine forests, rock formations, riparian corridors, wetlands, and creeks and waterfalls provide unsurpassed natural beauty. In contrast, the landscape surrounding the Exit 180 site is a patchwork of native and non-native plants, mono-cultural grassland, and areas highly disturbed by sediment accumulation, snow storage activities, and traffic patterns. The approach to the proposed landscape design concepts draws on the aesthetic qualities of the surrounding valley, and on select features within the project site, to develop a palette of context- appropriate forms and materials. The Exit 180 site is a gateway to East Vail, and the location is highly visible to all motorists, pedestrians, and bicyclists traveling through the area. The proposed concepts address the need for aesthetic improvements appropriate to the site's context and use. As discussed previously in Section 2.3, the proposed landscape improvements must provide multiple functions. They should create an inviting and aesthetically pleasing experience while complementing and integrating with the water quality improvements and current and future maintenance demands. Our approach integrates landform, plant material, stone, and hardscape elements to balance aesthetics, water quality, and maintenance activities. Prepared by RESPEC, Inc. Page 7 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements While the concepts aim to balance functions, aspects of the aesthetic landscape treatment may affect current maintenance practices and require additional maintenance staff and equipment. Additional snow hauling, maintenance of sediment vaults and other water quality infrastructure, and landscape and irrigation maintenance will result in increased costs. The Town of Vail should estimate and consider these additional costs when evaluating alternatives. 4.2 Existing Exit 180 Landscape Conditions As shown on the Exit 180 Existing Conditions map in Figure 6 on the following page, the Exit 180 site landscape is currently dominated by a single grass species, Smooth Brome (Bromus insermis). Although Smooth Brome is a non-native grass, the current stand has value as a sediment stabilizer and groundcover. Within the Smooth Brome are patches of wetland plant species shown in Figure 7 below, fescue species, and a variety of tree and shrub species. Figure 7—Exit 180 Existing Vegetation 11‘10.01,r s � 111411110111110111 111111.11. E 11 spa Current snow storage, winter road treatments, and traffic patterns have adversely affected several areas within the project site. These areas are in high-visibility locations as shown in Figure 8, and sediment loads and snow storage methods result in very poor or non-existent plant growth. Figure 8—Exit 180 Existing Conditions at Southeast Corner "CI -‘111064111 4. Prepared by RESPEC, Inc. Page 8 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Figure 6-Exit 180 Existing Condition --- -- .___------',--;-----------_-::-042-5:---- --_ __ _ - _ _---------th— — -------------------------- _ �g�' 0 0. o o m };.' r4,--kkF �`�,.-_-__--- - $G- ----— _ may- _, -- i qr ®_ • S . .-._ ' 1 -may !E'VA t-c .4.,--,..--..._,.., • 40--------- . C:2)/ 0 s Li - ------------- 0�e----------- 17raf.eRoad ------ -------- - 2414i Fall neQDr. !Y ----:_-_----._=_-7-_-_,--- r-N---r--- - - _________----- , - 4k. do Af.,., 4,...oe• . e 0,,, 41' el tk ke 0-0'i,...-.0' --__ *so -rte ® 1 L e' �1....m.. �- -- ti, r � —. �Y �_ ter`-- �— J_ 0 � �~ ~~` __ - �_ �..__4 ti -------- --_____, ---- ..------- Iiii--17--y .- *t. �J1 -, as i 4.41111t--..--- ---- --- - -- __, -- -,abl...1.1.-°".... '.+.t ail a OO �' lll� ,<n`O 0 4M O1000 aloft° Q �, tId o P�I\ � jl� - � O Parking7-_- a' . � ...� ir _ ' �— - �' li, _ --•„ .-�� _ '._ _ (14 _- - s ,_ .. Big Horn Rd. --- r - ..)T-.- . . .k.,4.`+► _ Gore Creek _ " Legend ttt-1- ----- f a N b 0 Existing Tree — 16 ., BikeTrail11�IC 'Snow Storage ■ Existing Inlet 1CD 7m177 a Existing Wetland Plants f 11......_ Existing Existing Topographic °1 Views • Existing Signage 0 25 50 100 Existing Grass(Primarily Existin Boulders Smooth Brome) Sediment Accumulation g Existing Condition .JULY 2016 1-70 E Vail Landscape and Water Quality Improvements MUNDUS BISHOP CO I$IIITIN6 k SSRVICES Prepared by RESPEC, Inc. Page 9 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Figure 9—Exit 180 Proposed Concept Figure 9: Proposed Concept -- ._ Lfit Qo '1-0 00 it o ` - :�n y 00 ti ° ��� mall Latae Dr9--_;._ 1: • 1-7o FrontageRoado� 5ee f � •� • 0 c o O o p Q Enlarib gement • • @ e a Figure 11 b -------- -- —„ ` --,�i __,.. ilkih . --- -T__ -*•,, 7•,,--i,z) ...,_"____.1r-..,4"4,`". 1-.1.41111r5-#C ii\17--ilio--v-O....... :..44...,, -.- 40::._ -__as,• (i)__. daulliL=p .-.. ------ __ - •- c;:) D 0 ------- 7_-_:.-----___ ------------- - - 'K....„.... � _ �9`eVaHeR�lo ■ U" 5ee • • ���.�• •S �+ � . . . _ !+ 4 3 %. ----~ nal7raii Enlargement [ t7 p } O % g /� r ( �� •• o pa A Figure 12 p0o� Q Parking set `3) C7 f_:) 0 v,. CM (4Clit ' - + • �r F0 Big Horn Rd. • • �f� 111110 0 �. (sl :ter_ f' -- ~_� 0 III --\ AA. Gore Creek . Legend ,. . .. - _ 0 0 Existing Tree — Bike Trail �I Proposed Wall ��� Check Dams 0 Potential future Parking A Wetland Plants �' Views _] Focal Landscape Feature 4Q Wetland Polishing Area �0 25 50 0 S • Existing Boulderssormigive Enhanced Native Planting1 Preserve ExistingTrees Existing Grass(Primarily • Existing Inlet ® Re-Aligned Trail Smooth Brorne) w • Existing Signage •p Proposed Tree 0 Enhanced Topography Proposed Concept JULY2016 1-70 E Vail Landscape and Water Quality Improvements RESPEC MUNDUS BISHOP Prepared by RESPEC, Inc. Page 10 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements 4.3 Proposed Landscape Concept At the overall project site scale the proposed concept, shown in Figure 9 on the previous page, draws on the existing undulating topography along the slopes flanking 1-70, shown in Figure 10, to create a more pronounced pattern of rolling landforms. The concept includes regrading and installing boulders along portions of the existing slopes to increase and accentuate the wavy form, creating visual interest. The enhanced topography and stone also provides pockets for planting drifts of plants to add texture, color, and seasonal variability. In addition to the installation of large drifts of native wildflowers, grasses, trees, and shrubs, seeding and weed control measures are proposed within the existing Smooth Brome stand to increase biodiversity and enhance aesthetics. Figure 10—Existing Topographical Character 164 .11100 prom 4 Ilketikp- Within the framework of the enhanced landform, and in other select locations throughout the site, the concept includes focal points defined by more intensive planting, terracing, landform, and stone. These focal points are strategically located to provide a gateway into East Vail. Two highly visible focal points are identified in Figure 9 on the previous page, and illustrated in enlargements in Figures 11 and 12. Figure 11 shows a landscape feature concept for the northwest corner of Exit 180, at a focal point visible from the westbound 1-70 off-ramp and the frontage road. This concept preserves desirable existing trees, and supplements them with boulder planter walls, grasses, perennials, shrubs, and additional trees.The boulder walls are set back from the concrete apron to allow room for maintenance access and to accommodate sight distances. The wall faces restate the form and pattern of the geologic formations in the valley's adjacent mountainsides, thematically tying them to their context. This concept includes river cobble or angular stone around the inlet to provide a hard yet permeable surface for maintenance. At the southeast corner of Exit 180, a focal point viewed from the eastbound 1-70 off-ramp and Big Horn Road, another landscape feature concept includes a raised berm, boulders, and planting area as shown in Figure 12. By extending the existing berm along Big Horn Road, this concept creates a raised planting Prepared by RESPEC, Inc. Page 11 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Figure 11—Northwest Corner Exit 180 Proposed Concept _________ FRONTAGE ROAD . —, --. —.�– EXISTING TREES TO REMAIN - P 1.� ori\ c NATIVE PLANTING �' a , , 6� • "l : !.P - 'Wil1�' r – BOULDER RETAINING WALL oil - it . - a , do, . , ORNAMENTAL PLANTING K �1 ' , , • �Sx ?:1111/* til SOD EXISTING INLET DECORATIVE ROCK ARMORING ------.. ........N Prepared by RESPEC, Inc. Page 12 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Figure 12—Southeast Corner Exit 180 Proposed Concept /.. ' + ~ ~ SOD CONCRETE PAN f _ 011,OMJ - - TONE RETAINING W ALL /JRNAMENTALPLATING NM ,f NATIVE PLANTING ----141.iii . v '*'—' • lh — - AL- ROPOSED INLET j,40., 44 f ,�.. ���ti_]_ ,� i P. ::* - . ., - s• . r -- wilisor . : BO DER ARMORING `"''` \ s--N\,,,, I 't 1":115 ? -) 44:c 71 4_ N.. N.--`.,._,.....,.......::// 09N Rpt a "Ns''sN4'..NN'::\.,.. Prepared by RESPEC, Inc. Page 13 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements area at the focal view and screens a potential snow storage area, and stormwater and water quality infrastructure. This feature includes boulder armoring around the proposed stormwater inlet to allow for removal of accumulated sediment while maintaining a natural aesthetic. The same boulders are placed along the slope above the inlet, and extend to create the informal retaining wall. As in the northwest corner and other locations subject to heavy maintenance activity and adjacent traffic, the landscape feature at this location is set back from the proposed concrete apron. As depicted in Figure 9, a potential realignment of the Eagle Valley Regional trail may allow for the creation of a constructed wetland polishing area as described in Section 3.7. This improvement would provide an added level of water quality treatment beyond the sediment removal achieved by proposed upstream water quality measures. The proposed concept provides opportunities for sediment removal, infiltration, aesthetic improvements, and functional maintenance. Future refinements of the design will define the balance between these elements in more detail. Ecological and environmental inventories, budget considerations, and the community's desired aesthetic character will inform the next steps in the design process. 4.4 Plant and Materials Palette Given the context of the Vail Valley and adjacency to the Gore Creek riparian corridor, a mostly-native plant palette consisting of aspen, spruce, fir, and native shrubs, grasses, wetland species, and wildflowers is recommended. Native plants emphasize a sense of place, thrive in the local climate, and can provide a variety of colors and textures throughout the year. Within the focal areas of the Exit 180 site, there are also opportunities to introduce other ornamental or annual species for additional color and interest if desired by the community. Figure 13—Plant Palette Samples �. +a". a '4 -" , :, e _'.0',{1 ,,;:i.-1 g; ',�i F^` t s b-4 li 11' r-'--,;,r PR` f v i i i yap „ r '�� .y� . , • 441 #'.L i 19. „ 11-„.1f47, 1T 4" x 1 t�r,F 11 qF.- f r Td" 4 41 t\-, " {t, 4 -' i ¢ b r i d '. SGA" 47J,rA +� e• .. '"s 1 �ic -�` r •�I i 1 r f1 . I I , I. ` a3 ..8— ,c._1( r�� y , i " }F In addition to the above plant palette, the concept includes natural stone as a design element. Boulders, stone slabs, angular stone, and cobble may be incorporated into the design features. Large boulders can add interest and create planting pockets along steep slopes. Dry-stacked stone retaining walls surround select focal points and protect planting. Decorative rock may be placed between the concrete aprons and the planter walls to provide a durable surface that complements the landscape features. As Prepared by RESPEC, Inc. Page 14 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements mentioned previously, boulder, cobble, or angular stone armoring around inlets may be installed to provide a surface that accommodates sediment removal maintenance and integrates into the landscape aesthetic. Examples of these are shown in Figure 14 below. Figure 14—Materials Palette Samples .. t-mss. "�-ami-` ' •_. y �1 -v. 4.` A rt ft- • i ` 1.N� � �5�.'M L '4 3 4.5 Exit 180 Water Quality Concepts The water quality concepts that have been considered best suited for use at the Exit 180 site include sump inlets, check dams, sediment vaults, infiltration basins, and a wetland polishing area. The options for water quality improvements at various locations throughout the Exit 180 site, including advantages and disadvantages, are discussed below. 4.5.1 Retrofit of the Existing Storm Sewer System The current storm sewer network at the Exit 180 site consists of seven catch basin inlets and two main outfalls to Gore Creek. The most basic configuration of water quality improvements includes replacing each of the seven existing stormwater catch basin inlets with sump inlets. Sediment will accumulate at these sump inlets. It can then be removed prior to discharging to Gore Creek. Doing this alone will provide a significant water quality benefit in addition to preventing the existing storm sewer pipes from becoming clogged with sediment and losing hydraulic function. The sump inlets will need to be inspected at least quarterly during their first year of service to determine how often they should be cleaned. A vac truck can be used to clean each new sump inlet, and they are all readily accessible. To increase removal of sediment and other pollutants from the Exit 180 site, the downstream catch basin on each existing storm sewer outfall could be replaced with more substantial sediment vaults. These will provide a greater degree of performance than simple sump inlets and will serve as a more significant barrier to sediment from the Exit 180 site reaching Gore Creek. A sediment vault is significantly more expensive than a simple sump inlet but the level of performance is also much higher. Much consideration has been given to the idea that an infiltration basin, or some other form of biofiltration, could be constructed at each existing catch basin location. New catch basins would have their inlet points raised above grade so that polluted runoff would be forced to pond and then infiltrate into the ground resulting in water quality treatment. Various materials that could be used to line the bottom of these infiltration basins were considered. Options included combinations of sand, gravel, cobble, and riprap as well as a mixed media that could support a vegetated basin. Prepared by RESPEC, Inc. Page 15 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Due to the extremely high sediment load arriving at each existing inlet location, it was determined that none of the options for infiltration at the existing inlet locations would ultimately be viable on a long- term basis given the extensive maintenance that would be required. Vegetated inverts would be destroyed every time sediment removal occurred and would then have to be replaced. Sand, gravel, cobble, and riprap would be extremely difficult to clean and would likely need to be removed and replaced frequently. Additionally, CDOT is unlikely to approve a design that will likely result in ponded water adjacent to their roadways. Ultimately, infiltration basins would be a poor choice at each of the existing catch basin inlet locations. However, it is possible to provide an aesthetic element at each new sump inlet location that would provide a hard surface against which to remove accumulated sediment, but also allow for a minimal amount of infiltration. Figure 15 below shows the concept of a sump inlet and/or sediment vault being surrounded by tightly set boulders. These would be easily cleaned with a vac truck while allowing runoff to drain quickly to the sump inlet/vault, along the majority of sediment. Figure 15—Stone-Lined Inlet Concept I Irl I� F Lay INLET/SEDIMENTVAULT J_:.�1�i BOULDER ARMORING 1111141 1111Pa VEGETATION 1S - ' PLAN NTS • VEGETATION 11 /11I r� �F -. trial % BOULDER ARMORING SECTION NTS 4.5.2 Wetland Polishing Although infiltration is not ideally suited to a location that receives a large sediment load, once the sediment has been removed from the runoff, infiltration is an ideal way to remove dissolved pollutants and excess nutrients. If sump inlets and sediment vaults will replace all existing catch basin inlets, storm runoff leaving the system will generally be free of sediment provided the sump inlets and sediment Prepared by RESPEC, Inc. Page 16 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements vaults are properly maintained. It is proposed that a wetland polishing area be created in conjunction with the proposed realignment of the Eagle Valley Regional trail. This area would be located outside the Gore Creek floodplain and would provide wildlife habitat in addition to treating water quality. Maintenance requirements would be very limited provided the upstream sump inlets and vaults are routinely cleaned. Water would be allowed to pond in the wetland polishing area and infiltration and treatment by wetland plants would result. This concept is an extremely low cost option that has the potential to provide significant benefit to Gore Creek. 4.5.3 Check Dams Check dams could be used along the existing swales throughout the Exit 180 site to slow runoff and trap traction sand and other pollutants coming off the highway. Although check dams are not considered a vital water quality facility at the Exit 180 site, they would provide benefit and potentially reduce the amount of required maintenance each new sump inlet would have to receive. If used, check dams will need to be located outside the clear zone for CDOT to approve them in their right-of-way. 4.5.4 Concrete Sweeper Bays and Pans Several locations at the Exit 180 site could benefit from a solid shoulder. The current cinder and crushed asphalt shoulder material is not aesthetically pleasing and has the potential to migrate to Gore Creek during a large runoff event. It appears that vehicles often leave the paved asphalt at the Exit 180 site, potentially encouraging mobility of the cinders and crushed asphalt. Concrete pans with varying widths to match existing shoulder width are proposed at Exit 180. These will stabilize the shoulder and provide a location along which a street sweeper can collect accumulated sediment. They will be sloped outward to ensure that snowmelt does not freeze on the roadway. Additionally, the westbound off ramp provides an excellent opportunity to locate a sweeper bay due to the extremely wide shoulder in this area and heavy erosion that currently occurs just upstream of the exiting inlet in that location. The edges of the sweeper bay will be kept several feet off the paved travel way and the bay itself will be sloped away from the road. 4.6 Water Quality Treatment Train The water quality concepts discussed in section 4.5 will be designed to function in series, as a treatment train. The treatment provided by each facility will enhance, or be enhanced by, the facilities upstream or downstream from it. Check dams, concrete pans, and concrete sweeper bays will provide pretreatment by removing the coarsest sediment. Sump inlets will serve this same purpose by capturing the majority of sediment that gest past the check dams, concrete pans, and sweeper bays. Two sediment vaults at the downstream end of the existing storm sewer system will provide primary treatment, as they will be able to remove the smaller, typically suspended sediment and floatables that may not be captured by the sump inlets. Finally, secondary treatment will be provided by the wetland polishing area, which will be successful in removing dissolved pollutants and nutrients, provided the majority of sediment is removed at the upstream treatment facilities. Otherwise, the wetland polishing area will become bogged with sand. Figure 16 shows each of these proposed elements on an overall site diagram of the Exit 180 site. The option shown is the preferred option that will offer the most benefit, but simply using sump inlets at each of the eight existing inlet locations will offer some benefit as well. Prepared by RESPEC, Inc. Page 17 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Figure 16-Exit 180 Water Quality Flow Diagram • O O rae. - - $44D- --- c_ccv? ...:___cs=0_,„--\_ ,,,...,.,...-- ---- -_-_---,-.:,:,.-...z----...:_-_—_,....-„,.-_____-.---__ , - t __.)._... ...._._,j Fall Line Dr. - V 74FrorRaaeR4ado-- 7:::_ "'D Q� O - - ---- — _ 700. o 0 a o�� ' I ' F1f` �yrv(ii ; * .f �lAh�1 • - —I 1 5-:_, - --� — — r — — — I CEJ - - __ - - 4 - - -`\ I -I I- - - - - - - � N I I I -„Iv_ . 04.2111.-IV 11Pek W.'. AiltlIllum.., r Ter'- :1•64.454balfill4 I w, r - -� I - 04 * € -- _ EaExisting Storm Sewer.!e Vale . to be andoned \ * 'iII �_- -- -------- _ A — - _ d : n:< d_ ill n d _.RelorralTil oO / ��t07o C3 0 D ` C '�`° ► � oaro � I aOC�0O d , J__________0 41%NW ID -'-.1111-. ..-..-.10,..- i Big Horn Rd. "`__ - 1 .,, .7_,___. _ -Jimmiliimilmilm.,1 ii_ ii., I ; w --* ------------------Cr\........ f �'`� 1 Gore Creek W . -+�'�' - 0 0 Existing Tree im P rBikeTrail Sr.e'- Proposed Wall (It( Check Darns 1Q Preserve Ex isting Trees O• Existing Boulders Focal Landscape Feature Enhanced Topographydip Plants 77 0 25 50 100• Existin Inlet Enhanced Native Planting Proposed SumpInletExisting Grass(Primarily 0 Potential Future ParkingrExisting Signage Smooth Brame) — — — — Existing Storm Sewer SOO Proposed Tree ® Proposed Sediment Vault ® Wetland Polishing Area Proposed Concrete Pan -- -- -- Proposed Storm Sewer Re-Aligned Trail Exit 180 Water Quality Flow Diagram JULY 2016 I-70 E Vail Landscape and Water Quality Improvements R SPEC MUNDUS BISHOP CO SUE?VJ C a ar•V LIS Prepared by RESPEC, Inc. Page 18 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements 5 SNOW CAST OFF AREA The snow cast off area is the second of the three individual project sites. It is located under the bridges at MP 181.9. This area is referred to as the snow cast off area because when snow plows pass over the bridges at MP 181.9, a significant amount of snow, traction sand, and other pollutants gets thrown off the edge of the bridges. This snow and debris then settles on a large area between Big Horn Road and Upper Gore Creek that gradually slopes toward Upper Gore Creek. Recent pictures of this site are included in Appendix C. This site was chosen for water quality treatment because it was assumed that this heavy sediment and pollutant load would eventually migrate into Upper Gore Creek and contribute to the impairment of Gore Creek.A detailed aerial of the snow cast off area is shown in Figure 17 below. Figure 17—Snow Cast Off Area Aerial 1;1-' µY • ,. ' e �'y 1 l' } 1f a 1! Yes — - -., -:',- '...,V 1 . : 1 = , ,,,.: ._, ., .,,,_ .,:.. \„,...„ , :--:j _.. ''' 71:':"6'.14:'-'1:;::*:"r.'''''.: . L 61, `P " t 1 \ , The Gore Creek Water Quality Improvement Plan cites three categories of stressors as potential causes of aquatic health impairment along Gore Creek. These include riparian buffer degradation, the impacts of impervious cover and urban runoff, and pollutants associated with land use activities. Pollutants associated with land use activities that could apply at the snow cast off area include sediment in the form of traction sand used by CDOT, deicers used by CDOT, trace metals, and petroleum products. The originally proposed plan to treat water quality at the snow cast off area included terracing the entire site to limit sediment movement and promote infiltration and providing a perimeter ditch to convey the reduced runoff volume to a large sediment basin. A detailed inspection of the snow cast off area was completed during site visits by the project team and Vail public works employees on May 17 and June 15 of 2016. Pictures from these visits can be found in Appendix C. Contrary to what had been expected, the great majority of the snow cast off area had a strong stand of riparian vegetative buffer in place. Additionally, a thick layer of cast off sediment appeared to have formed over several years and appeared to be quite stable in place. In light of these Prepared by RESPEC, Inc. Page 19 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements findings, there was strong agreement that a "no action" alternative may be a reasonable approach to the snow cast off area, as terracing the site would require destruction of the existing strong stand of vegetative buffer and may result in more sediment entering Upper Gore Creek than if no improvements were completed. A third alternative was developed as a middle ground concept that would leave in place the existing vegetative buffer but also test the theory that the sediment layer was stable and stood little chance of migrating to Upper Gore Creek. This third alternative does not include any large-scale grading of the site that would destroy existing vegetation. Instead, a small surface sediment basin could be constructed while providing a low water crossing at the intersection of an existing access road and an existing drainage swale running through the snow cast off area. The drainage swale at the low water crossing currently has a drainage basin that naturally encompasses a large portion of the existing snow cast off area. The low water crossing would incorporate a restricted outlet beneath the crossing to slow low flows and allow sediment to be captured while also allowing the basin to drain. Higher flows would simply pass over the low water crossing. Figure 18 shows a more detailed aerial and proposed location of the low water crossing and surface sediment basin. Figure 18—Snowr.I.:_.1s, ,._ Cast Off Area Low Water Crossing Location` 1 ...v. . __ _ _ x. , f y . .:1_ -44 `r 6 - .-"-; ' . eiiii \' 4.; ."Iiii.- 40- " •. tae: - z .'. 1 t A Y Y' • S .-�/ • v I ., r.o M1:til i The existing access roadway would be improved as needed to meet CDOT requirements for maintenance access and the low water crossing would be constructed to meet those requirements as well. Any area disturbed by construction of the low water crossing and surface sediment basin will be revegetated with a native seed mix once construction of the water quality facilities is complete. Frequent inspection of the surface sediment basin will provide information as to whether there is active sediment transport across the snow cast off area. Prepared by RESPEC, Inc. Page 20 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements 6 TRUCK RAMP SITE The truck ramp site is the third of the three individual project sites. It is located immediately east of the bridges at MP 181.9. This area is referred to as the truck ramp site because it is located directly below the top of the westbound runaway truck ramp located east of the bridges at MP 181.9. Recent pictures of this site are included in Appendix C. This site was chosen for water quality treatment because it is located at the end of a long stretch of 1-70 that drains directly into Upper Gore Creek. The three existing inlets and one existing surface sediment basin are the last opportunity to capture all the traction sand and deicing chemicals CDOT places along 1-70 before it ends up in Gore Creek. These chemicals and sediment have a strong potential to affect the water quality of Gore Creek. A more detailed aerial of the truck ramp site is shown in Figure 19 below.The existing facilities have been noted as well. Figure 19—Truck Ramp Site Aerial • +� . tea• .. .y i„� -.� .. .'11' .7-:•.A.--- .`. ` • 1 ti --; F_ -. `7' •,r 1 Tt Vii':• . • 'a= ,;; - , Ex Inlet _ .•µ '41 it ^� •• ••A.; r - y f• _ L'4� s I The originally proposed plan to treat water quality at the truck ramp site included infiltration basins at each of the three existing inlets. Due to the extraordinarily high sediment load reaching each of the three inlets, it is anticipated that any engineered infiltration media would quickly become overwhelmed by traction sand and the smaller sediment particles found in plowed snow. Infiltration basins at this site would quickly become permanent retention basins or require a level of maintenance that is unreasonable. Given the heavy sediment load and minimal space available there are few options available for water quality treatment at the truck ramp site. Sump inlets and surface sediment basin are the two main options at this site. The choice between the two will depend on the maintenance equipment available or preferred for use. If sediment sumps are used, a vac truck is required. If surface sediment basins are used, a vac truck may also be used, but a skid steer or other small front end loaded may also be used. Prepared by RESPEC, Inc. Page 21 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Ancillary treatment at the site includes the potential to grade the outside of the eastbound lanes to drain back to the inlet located in the eastbound shoulder. This would reduce the amount of runoff running down the south bank of Upper Gore Creek, thereby reducing the amount of bank erosion and sediment migrating into Upper Gore Creek. All disturbed areas at the truck ramp site will be revegetated with a native seed mix once construction of the water quality facilities is complete. Improvements in the 1-70 median and shoulder of the eastbound lanes of 1-70 may require additional guardrail to be installed because of clear zone criteria. Access for maintenance activities will be designed in consultation with CDOT maintenance staff. 7 CONCEPTUAL COSTS The total project budget for water quality improvements at the three individual sites is$1,140,000.00, of which $700,000 is federal funds and $440,000 is from the Town. The total project budget for landscape improvements at the Exit 180 site is $1,090,000.00, all of which comes from the Town. These figures include design survey, professional engineering and professional landscape architecture services, environmental investigations and clearances, geotechnical investigations, and project coordination. The purpose of a conceptual cost estimate early in the project is two-fold.The first purpose is to provide a comparative analysis between the various concepts and alternatives presented. It is helpful to know which options will generally be more expensive and which will be generally less expensive to construct. The cost to maintain the various types of water quality facilities and landscape elements over time is also significant, but has not been evaluated specifically for this report. The cost to make changes to snow removal and storage operations has also not been specifically evaluated other than noting that changes to these activities will be associated with an increase in cost to the Town of Vail, perhaps even requiring additional capital investment in snow removal equipment and staff. Town personnel are the best resource for determining the cost the Town will incur to maintain water quality facilities and landscaped areas. There are certain costs associated with every project that are traditionally bid as lump sum costs. These may include mobilization, construction surveying, traffic control, temporary erosion and sediment control, and water control and dewatering, among others. They are often estimated as a percentage of the more quantifiable bid items. For the purposes of this report, these bid items have been assigned a value of approximately 25% of the total cost. This value will be refined in future design phases as the nature of the improvements is also refined. A contingency of approximately 15% has also been added to the estimate. Current conceptual estimates for water quality improvements at all three sites and landscaping at the Exit 180 site are included in Table 1 below. Recommended improvements were intended to match the funding available for all three sites, but there are options for minimizing costs. With respect to water quality improvements, Option 3 included in Table 1 will provide the most benefit for the funding available for the project with consideration being given to maintenance, CDOT roadside design criteria, and aesthetics at the Exit 180 site. Prepared by RESPEC, Inc. Page 22 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements With regard to landscape improvements, the proposed landscape concept that is presented and the associated conceptual cost estimate reflect a comprehensive approach to improving the aesthetics and ecology of the Exit 180 site. As the concept is refined during preliminary design, the Town of Vail may choose to shift or reduce the allocation of costs from one or more landscape elements to others, or to reduce overall landscape costs if necessary. As the designs of both the water quality and landscape improvements progress and are refined, changes in anticipated cost will need to be considered. Table 1—Conceptual Costs Location/Improvement Items Included Conceptual Estimate Exit 180 Landscaping Full proposed concept $961,000 Water Quality Option 1 8 sump inlets $234,000 Water Quality Option 2 6 sump inlets, 2 sediment vaults, concrete pans $643,000 Water Quality Option 3 6 sump inlets, 2 sediment vaults, concrete pans, $819,000 wetland polishing area Snow Cast Off Area Option 1 No improvements $0 Option 2 Small sediment basin and low water crossing $51,000 Truck Ramp Site Option 1 3 sump inlets and site grading $81,000 Option 2 3 surface sediment basins and site grading $70,000 For the purposes of cost estimating, the grading and infrastructure required for the wetland polishing area is included with the costs of the water quality improvements, while seed and other plantings are included with the landscaping costs. Similarly, while concrete pans along the asphalt roadway will provide aesthetic enhancement, they are primarily intended to facilitate sediment collection and are therefore included in the cost of the water quality improvements. Finally, while check dams will serve a minor water quality function, they are primarily aesthetic landforms and their cost is included with the landscape costs. 8 REFERENCES Leonard Rice Engineers, Inc., 2013. Gore Creek Water Quality Improvement Plan, prepared by Leonard Rice Engineers, Inc., Denver, CO. Alpine Engineering, Inc.,2015. Gore Creek Action Plan Storm water Control Projects, prepared by Alpine Engineering, Inc., Edwards, CO Prepared by RESPEC, Inc. Page 23 of 23 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Prepared by RESEPC, Inc. Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Appendix A Appendix A of the Gore Creek Water Quality Improvement Plan Prepared by RESEPC, Inc. ` r 1{ sF# ..01, 411111.4' a .14. . I .`‘• ",./. .4. ' •.. . . '• 4 )4pr .c , . ..1110.:p :', A ... ii'2-4'.,4... 4:'.4,111;.1.."r .4.74':..'..ili(nr4,4 . .. 11, i 1 !+ 1 ;1 1 k r 1,t,-y * .11 A. rr rk{'i • , pp . ... , •• ,-; J... -a . . . . 4- i . .. 1414 +P.44:0 i . .... • e',IF":110111„ 1 - *''N .N.' ..o.,•.••• _ . .: . . 1,4; • . ,,,..• : .• 4. "Al.:AO. ' all?.A -„r ni4 ' . . if. . d 1, .1 Nei 4 if. Y .4 k r • 1 r . '. ..+ 4 . 7 a I I `' *+i'1 • F1 • 7- MIFF' Y N r.I•J. •' ,+I~� + • . ' F,rt ~' iii 3 t•• ', L}r+"t.57 .`'J ' • 5 5_ 77.1 f.• I' 4, IV L.` • I ���' '•i. , i 1 • J t • Cr ��F•$t 1 ih 1. f *...... j •4El .I y PIA 5 i . .'.4 r,:r',A;;.ipet . 4. 4 4. .1.-. ' -, . ..elf.!-''''r Ai'.- . ' .. • :1',' ' ON ' t . Jr+��j, a�IP' F F 1•' 1 r15..11 I. ll'. Ili:ivilk 1 -1111 'ft •r/..,0 M 7 f (ar 1 - A. . • ; ^ r � +mayX ' F e + t t 5 a 1 r ^#ti �7 w , Ir lytic k t • •. { , •.4 #. . ti4( _` • } • ' 'i ' _rr_ ,fr 1 T •*�'__ '!mss • . , • .4 _ al:'ll.' i .. Illti' . 3-"111111111. .'a • :air - ...: _ • 7.47.11: I ' .'IL7. 416 fbei, 1 �IIr r P IX A: 'IST OF BMP AND LID PROJECTS FOR . f i f" .- _ ,� ,.y STORMWATER AND DRAIN , I - • ; IMPROVEMENTS + • ." ' "4+ r• . `.+ r1 Or s 44141111111411* • . - -_ • • J 1 • - ‘..[::r .,X141 I -414116- '•A • ill • f l . { • • .t „r€ y ; a • „• 4•- + :-411r f '-' 1111"P'. . -,fr y - " . } r t • Appendix A List of BMP and LID Projects for Stormwater and Drainage Improvements The projects listed and discussed in Appendix A are conceptual in nature. Each project will require additional work prior to construction for design, permitting, and bidding, possibly including some or all of the following: geotechnical studies, percolation testing, drainage studies, and field topographical map displaying existing utility locations, current land ownership and easements. Individual projects will need to be evaluated for required permits such as: Town of Vail public way and grading permits, CDOT special use permit, CDPHE stormwater permit, or US Army Corps of Engineer's 404 wetlands permits.The projects have been listed and numbered from East Vail, upstream to West Vail, downstream. 1. EAST VAIL REACH PRIORITY BMP Recommendation Point I-70 Bighorn Road Overpass and Truck Ramp I-70 Location 39°37'34.97"N 106°16'40.55"W and 39°37'31.09"N 106°16'41.27"W Gore Creek Station 619+00 Potential Pollutant and Source I-70 metals and Hydrocarbons, Chlorides, Sediments, Snowmelt Concentrated Recommended BMP Retention Basins, Terraced Grading Estimated Design Fee $42,500-$52,500 Truck Ramp $40,000-$50,000 Over Pass Estimated Construction Costs $180,000-$220,000Truck Ramp $210,000-$550,000 Over Pass Category CDOT Notes Snow collection and overthrow store contaminants for large spring loading 4 Detention basin at existing culvert inlet 70' above stream bed-good for infiltration at truck ramp basin level 1. East Vail Big Horn Road Overpass and 1-70 Runaway Truck Ramp Retention Basins The major degraders of Gore Creek seem to manifest themselves even before the confluence of Gore Creek and Black Gore Creek. Evidence for this being the first aquatic life testing station that is upstream of East Vail housing after the confluence already shows impairment while stations in the wilderness of Deluge and Black Gore Creeks indicate healthy streams. One potential non-point source could be the 1-70 Alpine Engineering Inc. 9/25/12 A-1 drainage area around the runaway truck ramp. A preemptive BMP installed in this region above impaired water may have much more of an effect than any of the more reactive BMPs suggested within the Gore Creek Reach. Sediment control of this 1-70 corridor has been greatly improved in recent years yet actual retention of runoff can be even more environmentally conscience than solely separating traction sand and water. Retention of runoff under the runaway ramp forces stormwater to percolate through the ground to return as a base flow. Infiltration leaves the majority of contaminants at ground level improving water quality of Gore Creek below. The shoulders and medians of 1-70 below the truck ramp channel water towards the bridge over Bighorn Road below. Inlets direct water to the south side of bridge before it daylights over steep terrain into the confluence below. Small berms can be graded behind w- beam guardrails on shoulders and medians to create catch basins for the settlement of road sediments and contaminants. Although these basins will collect runoff and store the water above ground, it is important to note these basins do not have to affect roadside safety for passing travelers. The need not be more that 12" deep because the water will filter through bioretention soil mix, engineered to infiltrate the ground. Standing water will only remain after large storm events and their holding time is dependent on evaporation rates and infiltration rates of the retention pond base media. For this reason as well, plant selection is important and vegetation must be able to with stand flood and drought conditions. The heavier the vegetation is, the higher the uptake of nutrient and filtration of contaminants. Large runoff events will be allowed to pass through an overflow weir and into the existing sub-highway pipe system to Gore creek below. Layout of this regional BMP site can be seen in image 1 below. Alpine Engineering Inc. 9/25/12 A-2 ,.. ��` #: Vi _a �;. kFi'+-tp i } 0-4';', :his f. Ex' - - .ei Drain .d A. , a + ' ' T. a. J. (2) n V .. i -4',-- k A , • ilk-. A-.-•--,o it- k• I I_ f 1 • Itif';:. 7-- ., 2 . , t'.' „.,,,,4r. .. . . ., - , _,. ,..-,,,_ - l'. . .- 41' - II. . . •'—.....-• ,......:.?;,. -.:19.r. . AO 4 At w. �.,r. - l ` a .k yl P` diii Y :0._ft Ur f` "'`" ".-- :r - - - ,: .14.° , C1 o(21e earth Imagery Da[e.9f23.r!e9�F1 .,a 39'37'27.76"N 10616'41.98"W elev 8669 fl 4 •_ • Eye a,II 9631 fl Image 1. Proposed Retention Basin Below 1-70 Truck Ramp Just down stream of the Deluge Creek and Gore Creek confluence, a series of ponds have formed. Another 50 meters below those is a large grassy area that receives a large amount of snow plow overthrow from 1-70 and Bighorn road (See Image 2). Over the course of the long winter, snow in this region can collect a large amount of contaminants from traction sand and road salts to other vehicle hydrocarbons. Atmospheric debris also settles on top of snowpack and is then released in higher concentrations during the spring melt. The debris can be a significant addition of total suspended solids. An unsettled gravel road under the west bound bridge produces more runoff and sediment. Located just above the first 303(d) impaired reach, snowmelt and runoff in this region may be the first major nonpoint source contaminant loading region. Proper containment and treatment of this area is advised. The vegetation pressure in this area is high due to the constant relocation and collection of the snow. There are only a handful of trees and shrubs in the area, a meager buffer between snowmelt contaminants and Gore Creek. Utilization of terraces and capture trenches in the area would create lag time for the surface runoff especially during the spring. Capture of the water in detention basins after diversion channels would provide the important settling of nutrients and sediments as well as infiltration. Alpine Engineering Inc. 9/25/12 A-3 .It it\ r \ lI •F � 11,141% ti0f' Snow Collection A - `• To be terraced wit , •. '} , ; diversion trench an® ' �' 'Z. basin • Pr .:,_qt,„ - r~-fi•r +r; �• • if . : . , . . . , . __ ...._ . „.. ,, ,,, „ .. , ,,,,i, _ ..„ ,. ....,.. . ......,-, .. ._ ,,,,,_, ,, , „.. . ...„.. . . , ...,,_ _ , ,.. : . . i . 1440:30. r (a .+�r � •' ..0 a i. k•1 y r , r - t .Fri :.l. •, ,._ L h r1 . .' !_ . 1/ 4• ;� F � c. t y M .d'-'41#4:1 4^,s c ,. ,w • t . 5. « .'l +SOA P ,,-' "4,,Goog 7,arth Im ay el Date:412 312 0 11. 19'37'35'7.1'R}.1-06 16-2,2,,r4 W elev-8651 ft _ • Eye alt 9790 f1 Image 2.Snow Overthrow Location and Proposed Trench and Basin Treatment 2.EAST VAIL REACH BMP Recommendation Point I-70 Median _ Location North of Vail Racquet Club Townhouse Drive 39°37'50.39"N 106°17'9.68"W Gore Creek Station 586+00 Potential Pollutant and Source Sediment from Traction Sand, Chloride de- icer, Hydrocarbons from Vehicles Recommended BMP Detention Pond Category CDOT Alpine Engineering Inc. 9/25/12 A-4 3. EAST VAIL REACH BMP Recommendation Point Big Horn Road and I-70 Median Location 24" CMP effluent just north of Big Horn Rd. East of Streamside Circle E. 39°37'59.53"N 106°17'26.67"W Gore Creek Station 570+00 River Right, Potential Pollutant and Source I-70 metals and Hydrocarbons, Chlorides Recommended BMP Detention Pond, Infiltration System Category TOV or CDOT property?? 4. EAST VAIL REACH _BMP Recommendation Point Big Horn Road Location North side across from Streamside Cr. Bus Stop at Big Horn Creek 39°38'11.76"N 106°17'48.86"W Gore Creek Station 547+00 Potential Pollutant and Source Big Horn Rd. metals and Hydrocarbons, Chlorides, Runoff of all housing developments on North side of Big Horn from Streamside Cr. To the East Recommended BMP Bio Retention Category TOV Right of Way/Easement 5. EAST VAIL REACH BMP Recommendation Point Columbine Lake 39°38'17.34"N 106°18'3.43"W Location Gore Creek Station 528+00 Big Horn Rd. Hydrocarbons, Sediments Potential Pollutant and Source Residential Phosphates,Nitrates Bio retention System as a treatment train Recommended BMP with Columbine Lake Category TOV Property Alpine Engineering Inc. 9/25/12 A-5 6. EAST VAIL REACH BMP Recommendation Point Big Horn Rd and Pitkin Creek Intersection 39°38'31.43"N 106°18'18.42"W Location Gore Creek Station 510+00 Big Horn Rd. Hydrocarbons, Sediments Potential Pollutant and Source Residential Phosphates,Nitrates Recommended BMP Bio Retention System Category TOV Right of Way/Easement Notes 12ft above Gore Creek Bed Alpine Engineering Inc. 9/25/12 A-6 7. EAST VAIL REACH PRIORITY BMP Recommendation Point Big Horn Rd, I-70 Exit 180 39°38'37.68"N 106°18'30.04"W Location Gore Creek Station 498+00 Big Horn Rd. and I-70 Hydrocarbons, Potential Pollutant and Source Sediments Recommended BMP Retention Ponds Estimated Design Fee $42,500-$52,500 Estimated Construction Costs $230,000-$280,000 Category TOV Right of Way/Easement, CDOT 6 or more ponds can be constructed in area to handle excess cinders and contaminant Notes loading 7. 1-70 East Vail Exit 180 Retention Ponds The 1-70 East Vail Exit 180 area is comprised of a large area of impermeable surface.The contaminants on the exit ramps and frontage roads include petroleum hydrocarbons and heavy metals associated with vehicle operation, all of which are transported by the water of a runoff event. Engine oils, antifreeze, brake dust, fuel, and rubber are left behind on roadways, especially in areas of rapid acceleration and deceleration. Road salts, traction sand and trash are also deposited on these roadways introducing even more stream stressors. Precipitation that falls on to these surfaces collects and concentrates contaminants which are then channeled through the stormwater inlets and piping directly into Gore Creek. Contaminant detention and treatment is critical to improving water quality. A preliminary evaluation of the area shows that precipitation falling within the blue region, highlighted in Image 3, will collect in the areas highlighted in red. These depressions are filled in by intermittent grasses which help with a nutrient and contaminant filtration, however the area can be better utilized for stormwater quality. Alpine Engineering Inc. 9/25/12 A-7 r I" \ti .k.. r # _ +y. y r, 'lam, '•i( •bisection,. ' it% ,.‘, ,_ .. ..?•:. .- , .1.r - k'. "r - � �;SS • Imagery Data'9/23/2011 39'38'38.84"N 106..18'25.88":W el2"v 8393gft? li'L - E'11 c.]I; 10362 f[ Image 3. East Vail Stormwater Catch Basin and Proposed Retention Basins The University Of New Hampshire has proven retention systems such which can effectively treat suspended solids (97% removal efficiency), while meeting petroleum hydrocarbon quality standards for the state.They can also remove 99%of zinc.While removal of road salt chlorides from water is minimal in all natural systems besides total evaporation of water.Vegetated Infiltration systems do reduce the spike in chloride levels by slowing the stormwater input through detention. The existing stormwater inlets capture water from the blue highlighted area and channel it parallel to the underpass road to Gore Creek. The depression areas surrounding these stormwater inlets have excellent potential as bioretention basins. These basins would provide an area for sediment capture, pollutant treatment, and infiltration of stormwater into the groundwater. The area already provides substantial snow storage which could be modified to retain the portions of runoff. Proximity to level roadways allows convenient access for construction and maintenance equipment. Images 4-9 illustrate existing conditions for proposed location. Alpine Engineering Inc. 9/25/12 A-8 • NI c .411100, .wit. M1 Image 4.Current Inlet south of EBI-70 Off Ramp(Imagery Date 8-29-12) "111111111111Pir _ter 3'. N rl F.fr• f 7•} Irk- • 111 Image 5.Current Inlet south of WB 1-70 On Ramp(Imagery Date 8-29-12) Alpine Engineering Inc. 9/25/12 A-9 unt WAY • I• m rix f ' X4s "i�aa fif � `4 ti } ys • .7 mil • Image 6. Current Inlet North of WB 1-70 Off Ramp(Imagery Date 8-29-12) ,. d7+• _ f 'A4� - ..,.ems - _!—• Ar- - • • Image 7. Current Inlet and Grading of EB 1-70 Off Ramp(Imagery Date 8-29-12) Alpine Engineering Inc. 9/25/12 A-10 Appendix A References Aspen Urban Runoff Management Plan: http://www.aspenpitkin.com/Departments/Engineering/Stormwater/Development- Construction/ Denver Urban Drainage and Flood Control District Drainage Criteria Manual http://www.udfcd.org/downloads/down critmanual.htm Information from University of New Hampshire Stormwater Center including the 2007 and 2009 Biannual Reports: http://www.unh.edu/unhsc/ Seattle's Stormwater Manuel Vol. 3 Stormwater Flow Control and Water Quality Treatment Technical Requirements http://www.seattle.gov/dpd/codes/dr/DR2009-17.pdf Alpine Engineering Inc. 9/25/12 A-24 Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Appendix B Gore Creek Action Plan Stormwater Control Projects Prepared by RESEPC, Inc. 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' ,Ir ,: .: - ;. WIIIIIIIIIIIIIIIIIIIIIIIIIIZ ��� 1A. Gore Creek Station 622+00, Adjacent r' w',•'.:- .: F , Li to I-70 below 1-70 Truck Ramp ;# •Y ", ;. 't :�,:.:�' k 'iI' ..- a' ;. Z c� Proposed BMP Recommendation: Forebays '�� ;. `� :R. r a j` .. y" — -� r W�. P Y y f ,�:_ III III bj m., and Sand Filter to provide treatment and • r M 1 •., '" ....^ `�" �—=-. ' J w �� � � � s "; r IIIIIIII IIII le remove pollutants, including sedimentation, ,_: ' a I a t Q IIIIIIII filtering, and adsorption of constituents. - i `�'••, � '•' ••4 ?�' j� — �Illz .- -_^... • Pollutant Sources: Pollutant wash—off from -� _^' ''';',.‘,'.."5:;;,....- �y�. "� > .: • ::r-x •,-,51(: •^ :s14-,7 !,.. 7:_"..',: ,.`(1' - - .'` •+i, _ Yf 1 1 ' y ` . :x . � . r,10,44'ti r ,''`�'.' _ fix: r',..'A 1, r 1-70, sediment, cinders, hydrocarbons, trace <" 01.'• ,'_. �r, ��: : "; - ; r" „•..:;,; 5'.i '' :=.. .",:~• .y..•_:;`-'":(�.;.��-`,•.:i�b'--v-). 1 �f�_ �'i _�/•: .V `•'�:ty'. u�: .y^�; ' ". .'i �'i '' � ( metals, road salt and deicing chemicals. �- -- � r _ :a,'. _� =„ '�• .--� ; :� �� • � �� c.- - - ^.'_„ - '•k'µ'� r �ty ,�.:_ Ili Ute Property Ownership: 1-70 R.O.W., USFS 4 ti' x t1 ' :' y` ' ' �3,w :fir , *� fir= k�i 1 -u ::; " _, �'., j r ...�,�, 2 n ,.. { - . Lat/Long: 39°37'31.24"N, 10616'41.34"W ; - ;�.;K;.:. '; ';� ,, ' :�. '' • '; •;�.,� rr[ ,mac Potential Permitting] CDOT, USFS y - - '' wrr' :h, ; ; v, .:i 1 r ,•7r yT - ..tr nR„•�''▪�'�• '•rte•'•• .L•;'T�:,: 1 Al-4' .7• TT ..}� ~�"•- Potential Partnering: CDOT, TAP grant � ,,4 I -Y`. . 4•:A' `j�'n� -It A, ,� " I. . .i -: .; ”, ` .'.1,i:': ';-r:':F i J 0 Estimated Cost: ;: ;' :. �y ,• P �.x 1 n Z Construction: $110,000 c4 s f r-.-. - 4 , +. YA r+:y;;:�, , pd.i,•• x , !'a+r: 0 04 Design and Permitting: $44,000 " rz. _- r •. .�� . • ,,die • A. • _ .. rw.r.> .°:, F " _ zr 000 Total: $154,000 }�sr ,._ _'I, �.„ .. - _ - ' � '-' `r *.` t, - ,:. 5. al Notes: Sand Filter and Forebays. ttF 'Kt:.:r; i. � c ; Q Next Steps to Proceed to Preliminary Level: ._ , }. I �J a� ^' Detailed Field Topography, Utilityxx"=z ` _ - 1. 'm '1,- " Existing ,. Locates, Geotechnical Evaluation, Ie•'?'' •�- -'`'' +: -� j 4. F . I ' <-11` ,gyp :1 •'{ ': - - i:: ‘„a.r Ot.;. _ -�i:' Environmental Clearances, and engage CDOT ,s. q r. u ,. i:ti • o in discussions. § k:.5;•••41C :3.:. 'x` ,� ' � - 0 N '• •% :}.., ?,A.�a'. 1. 4za "r: :• Y:" _ •.4•+f ' kr :'A.:. •.w 1•y .3'. /C :0/4 ., S .•).r •L'--',i i' '.;''4,'/-" R.•F. :f' A "r. r��r '. ' •I e '-'..H %Ld , •%_ //o/� Ln Priority: Rated Level 1 because there is a f y •��•.���� �':..�.� r.:�� � •S . �6'�RC' ;' � - .--I ��, _• '.b ✓'A yet. 'if .-p'•itk, '''• ' = large amount of traction sand and other ' �'',I '� I. pollutants from 1-70 with poorlymaintained ' ' '� - - :'° )' -• . x treatment or catchment. There appears to • .moi :. , . " ' '� � �;.•� r�•y 2. i • ; '; ry IA k-, 0 be space to provide Sand Filters and to , " r1� � r. Qprovide and improve Forebays. 0 61 N SEDIMENT FOREBAY .: RIM yam•, -_ PER PLAN 1 / r0oq? RIM 0 (TYPICAL) z Ci. '.".'=""... _ I I I Ii �Qa INSTALL FABRIC MIN 4" ABOVE — I I I I I I 15 Tr F® SAND LAYER, KEY IN AND Z •, II. 1 R7 STAPLE. OVERLAP FABRIC BY CLEAN OUT WITH (2) ce M4,1. 18" MINIMUM AT SEAMS 45'BENDS WITH I FOREBAY TREATMENT BMP III= WATERTIGHT CAP TOP OF SAND FILTER , • rr U) RIPRA - - 4.5'L x 4 5W TYPE L - ,� i OR PLUNGE 000E MM) V RIPRAP RIPRAP BOSBE v - PLACED OVER _ > If z p GEOTEXTID FABRIC - _ III III III II III TI ETl" OUTLET PIPE AND VOIDS TO BE _ \ Y FILLED WITH CLASS C I I—I 1 1 I I -III IIIIII -- b FILTER MATERIAL —�i i Qi FOREBAY TREATMENT BMP III- 4(MIN. UNDERDRAIN -:a D e , a ! U) 23" DEPTH CDOT PERFORATED H A-2000 a - 0 n C INSTALL MIRAFl ao �-I HEADWALL(IF OR APPROVED EQUALTERWEAVE PERFORATED PIPE) /// r v �n 01 CLASS C FILTER MATERIAL OR EQUAL / Q = 0 ,,, SAND TREATMENT BED / e, o .� REQUIRED) BELOW SAND LAYER NOTE: THE SAND SHOULD BE MOISTENED AND z z w z TREATMENT VOLUME c> W W z 0 INFLOW AS SPECIFIED(SEE MODIFIED TYPE C LEVELED WITH LITTLE OR A COMPACTION. THE INLET SUBGRADE SHOULD BE SCARIFIED ABOUT 6 TO 8 w rc x p DESIGN CRITERIA)EINCHES DEEP AND LEVELED WITH LITTLE OR NO 0 0 " 0 I / CHECK AM COMPACTION TO INCREASE SOIL INFILTRATION ii OREBAYI/ TREATMENT RMP0-1 CHARACTERISTICS. RIPRAP APRON NTS. SHEET CR PLUNGE POOL D SAND FILTER EXTENDED DETENTION BASIN TYPICAL DETAIL 1C 0 a .. , . a r PRIORITY: ► yZllllllllllllllllllllllllllZii i �P ....kirvik - ' .--"J s • r ... .., _ .,. „ .. . ....., ,„,� _.:�` �_•.•__,... 4,411.--:.N2( �. *.• CB ��� LEVEL 1 .. a � 4. •�- - `.( �- , •-- [�• - - F �. 1111111� IIZ X05 ItSt Iiiii,„ _ . , . a 111111 2.%. • I • ot '14 lilt ' \If 1 F' I " • I 0\GN3RNr Ilk,N....1',...„ \y ` 1 II 1 0 lik .a n y b Ii ili.: / \-- r:. • 7-— > CON WI ,+ i0 . s r • UUPO/ A • I - - - - - _t ✓ -z _ - / 7 illk 4. / aCC "Ilk . �/ 1 1 W iVl` / I I "4 / / W2ArC . ._ U IM Ir a — I .€ � oo � 0 N I SITE 1B * sit ........_ 6ti5= r:.; 1 ,vir* ... 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' ''?-'5°C' ,Ig 3. ‘O'4" ,,, ir 1 ill- ,Z:4"'C-1 ' 1 j'' ''' '1 di*: .../ er. •c __ 140 f - ja „ III a s _ -- Q V1 • _ ro P r\k. _ I 1' g19x00 J n 111111111 • I 4 O Q £ /')Ik'. •i 'a1 — . / _ 818+� ` ai _ �I o 6, ; 11111111 s hi ... 4411.k•- , . . . 411,4 Q S Y Y O �, o rc) ; _ GRAPHIC SCALE W w o 0 \\-\\ \� / f - - - / + -- - 5r �` '�• ' - 24"CMFO z 6 z I _---- CB f 0 50 100 200 E E = q' a \ /\co , \ — FEET SHEET O — 1 s • s ` / a 1 inch 100 ft 2A o - L �cIdH \ cb 6 N ------\ -_ -_� i �s. \ � \ \ 6a. .4,I f \\ 1 \I 1 ,\ , , \\ \ \ 1, /CB \ \ . \ \ \ ` 1\._: \ I \ \ I - � \\ `\ \ ` " '' '/ ( III III ug. / A\ I .\ \ \ \ \ \ \ . \ I \\\ \ 1 `\ • N \ \ \ \ \-, \ r. \ 1 -- ` , --' - LL, / ( \\\\s/1 \ I • ` \\ \\\\ \ / _\\ \1\\\ ��?\ \ \ 1 / \\\86584 \ \\ \ \\\ \ \ `_r�---------' / IIIIIIII IIIIZ �'� \ \� \ \ \ \\� \•\ \ / a4 .7c\ \\\\ I ��\ � \ \ \ \ ` Ili'/ _— \`� ` �/ /✓ ��� / — /• III (7 0 \ 951' • ,► \_ _ \\N\ 1 \\ \ \ \ , �s --- -- J IIIIZ oWa \ \ ' \ \ \\\\\`\\� \\ \\\\\\ I \\ \\\ \ � \ -ice _---- ( ,// \ \�-i \ /. c \ \\\ \ \k ,\ / ill \ \ \ \ \ \\\ N\\ \ ,\\ •\\\\\ / \ / _...... 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I \ % / /�// //OErtse r/d�s I I 1 \ \ \\ m x-r 1 \ -. \ ... ---\. -_-„,,,-...,-.,:- _‘1 • -:_-- -----........------_.:-.- ---- ___ N -\-„,... •-•„„. ----ill* __ __-, • N m l \� \ \ i -- \..J \ \ �, .r \ iet 446_ - J \ \ • • • ---- . - . •i / / / - - 0 / 1 \ --:8, -- 'lir '2., •--: -- ' / .7 •-• --- 7 7 7 d /1 \ \. ` 1 -k' ,2-- 1 _ \ - iii \ /7N- 1 \ �1 (�` 4111\ R• i��- D ----' -�-- // -'- -�' �/ --- �' S CO LII' \\ s.• \\ \ I�l - - % _-' -- f -' --�� I \i I I , '�� '�/ i// � iii �� i� ; / \\\ \ ..\\ -J \ \ \ ii'- / /----.-:"----:>.�• . • 4. \ / _-� 0 / •/ o ---- / d - -- -- -i �-\ ; \`\\ _/-- - i• I I, / \ •`-� - \\ •` \ ` // /� //✓ v 86899. -- -- - - - - / / I v V -- ` -� i l I I , / — C / / / / / / / i 86888. • / \�/ ------ '- - / // / /1 o � \ \ •s I\ \,6'1 W I \ \\ + ----'I --/ iii//////i✓ �� / I'1/ ) 1 / / 11° I I I ---' ' //////// // X/ I \ •\ \ \ v / \ / 1 / III / \ -- -/ I 1 cI'N / 11\\ III/ 1 1 - --1 I I / 6 • --- — -- -- / / / -/ \ / I / / 1 / I -1 7///4!.• , / - — 23630 _ --// 1 I \ / ` I I / I / // I/ N , \./ I I l / J --- --- G— // — a = r v o - I r' / --- / \ / \ 1 f / ' I / / / rA� CC�Ak.E/ w o 1 J / I I I r / 1-= --_ CBS / I / / so/- ioo 2 - w o `r Z ) J �' ( 1 I GNF 8691 3 / / / / / / /� -/ , 1 i' o o v o o. �_ f 1 1 I / ^� _ / / I I1 J / / / r___40,. �• l I / ' Q- �. -i•�F I / 1 1 1 1 1 I / / - \ / k. -1- _ / 10E/ / / ,/ J/ ' \ � .• .( X �858 .1 \ I / I , I \ \ I / J \ 1 S / I / / / -' 8751. E.- / - �/t" I I 1 I / 1 I I / / / \ II \ j / // / / / / /--, / -- o _ \ I 1 I -�� \ I / I / / / /7-7_ - ' 7ss w \ X )' I \` \ \ / I I 1 \ 1 ! 1 / / �- / / / / \ (IN/ T� SHEET r V \ \✓/ / I A I 1 1 / I / I 1 / / / /// v , A ",� > \ 8582.7 1 \ 0 i'-/ \ I I 1 \ \ I• \ \X 8�o9.Q I / / / I tw / yv0 ft/' I I 1 / / / III I \ 1 in / 2B - - - I I / / I I / I I 1 / / I III /// //i % / X/, / O �� \ / 1 \ v 1 / / I 111 \ a GO \ 1� - i - . ,t \ / /ic. l ! / / 1 1 \,� 1 / I / �l i i l I ��\--' // ii,/. `•//i// / WIIIIIIIIIIIIIIIIIIIIIIIIII Z � 1B. Gore Creek Station 619+50, Z — a^ 1-70 Bighorn Road Overpass W= ',t = air d• na Fr.::-• .w � •. I•f. "��.." aIII III W�"' ' 'r, Jw �„ Proposed BMP Recommendation: Forebay and .,, • ;,4 -� ' • s' � c � . poiBioretention (Rain Gardens) to provide treatment .-, + a 11111111cDand remove pollutants, including sedimentation, '' - :� •""•' _ 4 r `,'I.` h.-a- IN '' ' IIIiw oWafilterin adsor tion eva otrans iration andw '`g� P P P , - - _.�rL• - T L �_ z biological uptake of constituents. � {*: '' ° } ,- '. r •' ;F is • Pollutant Sources: Pollutant wash—off from 1-70 - '' LI -. and Bighorn Road, sediment, cinders, hydrocarbons, ' ` :,;1•'f-`�I.,K _ ., trace metals, road salt and deicing chemicals. '`` T `Li..':` '''''' e'.` Property Ownership: 1-70 R.O.W., USFS IL :,;.;' ; Lat/Long: 39°37'35.04"N, 10616'43.39"W - .. .a : r: _r . _ '02 2014 09 02 2014 4 J Potential Permitting: CDOT, USFS, NEPA "" a Potential Partnering: CDOT, TAP grant , . : ' O _.,* `.: 44404e% ''Niz,, : ''', '-:,',.'.•f' - 0 m "IIIIIIIIIIIIr Estimated Cost: PoPi— _ ` >- Construction: X140,0004: ' _ 3"' '' ,;, V 6 Vic, �11, { .; O �, Design and Permitting: $56,000 a:� :' ` Nge% ,�' s; ^ " . b 'A' ::; WZ Total: $196,000 ri • ,_; • ..',7'....,..„,,,'L ;..;:-, ' - 44 w. I'I . . L3 'f-it'''''' 'r r r � .r °''' .'s •. ... ,x- 00 Notes: Bioretention and Forebay. .,� - ' Y -,,f, :,,,--,-.4„--.J._e,". - M (•.J :„1. :,''• ts'B.. I .- %,.C+ 1M %a.Cl/ CS Evaluate site to see if wetlands creation is _` ;-°'•�'_ ' `” `= '°" .: appropriate. ti, . _ S : _ ;IN, .. T • - :. .i4-4:. V �i y • .:-.-4.'';'•.4`..,":"-- - :- IE p fir.;. '' L.-, '':;-.. ;s . N Next Steps to Proceed to Preliminary Level: _. -.Lus:;4ti• , - -•. _,-.•;_--.A • CC 1— I Detailed Field Topography, Existing Utility Locates, I F "Y f' 'r � _: ' r (NI. 8 `n Geotechnical Evaluation, Environmental Clearances, 4 - �,f _� a = Wetland Delineation, and engage CDOT in 3 �I k ,•�,� X discussions. rig ;, -...:..t.,_.'", _J 5 09 02 2014 o Priority: Rated Level 1 because there is a large .. `= * - °J'. "•;' -"-iw=' m amount of traction sand and other pollutants from O 1-70 with no visible treatment or catchment. There is space to provide Forebays and Bioretention and possible wetlands creation. N O a SEDIMENT FOREBAY o a s 9 1 WRAP AU.CEOTEXTLE FABRIC TO TOP OF SOL.ATTACH FABRIC .: . DRAAND SHRUBS FIRMLY TO WALLS OR TRENCH ADES CU YM1D CO .-moi'; _. PER LANDSCAPING.DO NOT USE SOD PLL SIDE SLOPES}1 OR RAILER ALL ADE SLOPES 3:1 OR WRAP ALL FABRIC TO (4:1 OR FLATTER PREFERRED) INLET AND RIM iiii FLATTER(4:1 OR FLATTER TOP CF SOIL IL ATTACH FABRIC UNLESS VERTICAL WALL IS USED PER PLAN o PREFERRED)UNLESS FRMLY TO WALLS OR TRENCH SIDES ALL INLETS (TYPICAL) PROVIDE r MIN.HEAD CU L •ii � AtAX: PROM ALL SINLETS HEAD VERTICAL WALL IS USED wOCv N FOREBAY W°F DRYLAND GRASSES WATER L TREATMENT BMP RFACE SURFACE V �•.• = SU REALE WILDFLOWERS OR SHRUBS INLET AND RIM PER LANDSCAPING.DO NOT USE SOD PER PLAN O RIPRA• ON (TYPICAL) --......m. 31,---\ ij �113RT.!7/� V/\ OR PLUNGE -00L /I 1 \ \/%`\ \� � ��\//\/\ Q \\\\\\ 7YPE L PoPRAP(FILL __ _ /\ \\\ \ 'it D i SDC ALTER MMATERIAL)S MTN COOT CLASS //\ "tB SAND/COMPOST lO1L ASM C-33 SKID /\/\ N UNDERLAIN w/FILTER /\\ LAYER 309.TOPSOIL/ORGANIC \ VOIOC FILTER MATERIAL) IB-''.."'""b<'."-"C°."''''''' AN�D/ POS7 CpAP05T/SIftEDDED �LAIE M Y a] CLOTH / - j // ` J PAPER M'I /* /// Q S Y Y O MATTER ,I 30 MIL PVC UNER TO BE (p �/\ \ \ PLACED BELOW PoPRAP AND >• \ \ \/\\/. ////////\\\\/////'//\\// \� WOVEN CEOEXTILET�FABPoCILE FABRIC : P w 1o I IA Z Z Y Z FOREBAY TREATMENT BMP ASTM D4751-AOS US STD.SIE CLEAN OUT WITH(2)c45. N Q W m 0 WOVEN GEOEXRA FABRIC MEETING: 0 TO I�/O Ar GTH I MN BENDS WITIi WATERTIGHT CAP C ASIA D475gg177-AOS US STD.SIEVETAPE 2LBS. IN.O STRENGTH 100% 4-MIN.UNDERDRAI 6 E 6 O g �—I HEADWALL(IF TAPEIADAL TEAR STRENGTD SIEO'il X 60 LBS.NLN.OPEN AREA OF 4$.30 MIL PVC UNER TO BE PLACED (CONTECH A-2000 REQUIRED) 60 LBS MIN.OPEN AREA OF 40 BELOW GEOTE%TILE FABRIC PERFORATED PIPE)OR EQUAL - TREATMENT VOLUME SCARIFIED SUBCRADE WTI1 PER CaCAD ON `--I INFLOW AS SPECIFIED(SEE RATES EXCEEDING 20 MINUTES PER INCH 6.DEPTH COOT CLASS C FILTER MATERIAL G DESIGN CRITERIA) SAND TREATMENT BED 0 AM NITS � FULL INFILTRATION RAIN GARDEN NON INFILTRATION RAIN GARDEN SHEET > OREBA�RFATMFNT RMS 2C o O RIPRAP APRON A TYPICAL BIORETENTION SECTION B TYPICAL BIORETENTION SECTION IS: OR PLUNGE POOL PRIORITY: Ung og. _� r , t s LEVEL 1 — z s„ JIIIIII , n Mill zm�� -Al ;m N F° 1111111 z R�rqc w w . • SHALLOW CHECK DAM with BIOSWALE AND TF�STq /� ��� ,_ UNDERDRAINS (TYP.)" a cr . \\, ,, 0. e. , ,'rte Q J 4 \ \ -P: 'N yr�-''-� Y' �� BIORETENTION x .. `" ��4 R F 8 WN SHALLOW CHEet. ., B /\ - , '- • SHh BIOSWALE ? '� \ \\ �J U 0 >. '.: \` UNDERDRAINS (TY" �: �\ _ _ - Q WZ "` \ \ SHALLOW CHECK DAMSIli 1 ``+ ` 4 �.� with BIOSWALE AND - 4ikiRAISE INLE \ . " ,� b UNDERDRAINS (TYP.) W Q ia� / PROVIDER 1 W 3 a _ / C v > - BIORETENTION• \ ` / / / - ,_ . _ U CC . , ., , , r. 4 \ „^ ilkliop f FA' / CB BIORETE $ \ p. # \ / / 'a s k h a / . \ : . . . / SHALLOW CHECK �• 811111111 c=n t • \ \ INSTALL RISE ----� J ^ ` CONNECT with BIOSWALE AND -� t t t:,� UNDERDRAINS (TYP. \ • i,,4 i. \ S �'� S AND ei/ `�� P.F3 E ham/ / ”• ; r� c \ BI ENilON / \ _ f v *� 98X / 8/6X/ ,.__:_,:_\_FOREBAY °° << °R . 11111111 v N ROS r / ,� 4\\ 0 • Rte_ \. - - - a_ CSF\.. :::N ING / -\ \ \ Q = Y a o g GRAPHIC SCALE • o o o 0 50 100 200 • • - - .'� o .. is a > :� ? :, 1 inch = 100 ft. SOz*• t h : _, 1\'� _ .. -.-. ulllllllllllllllllllllllllll_' � �;� - ,;� \ PRIORITY: Z Z daR �\ 8382.4 8 ����_ ` \\ �\ \ O `\ C� •�X - --__,--.0 0 --__ \N.`\\\\`, LEVEL 1 a Z = , . 78.6 \,„� ` -� 0� \` ,„-„-.\\\ \\ ` ` \ \\._ '-', ---...._.`.` a\\ \`�\`\\��\ J 11111111 11112 ri \ ,\ 8382.9 ��\ ---__\ \ ` `\ ` \" II II �ol \\\�\\ __--- \X RpNq ` .` \ a \\\`\�\ IIw oWa NNNN �.��`\`N\ S • o _\8381.1 4 • \ \ \ \ /' �' ``�N ------ \ - __, Si3ALLe :.ECK DASI .` `\ -� I `� \�� /N \\\\\\ S I �� - - 8378.9 ,with-E1.10 : D `\\\\`\\\\\ \♦ /t `\`\\\\\ QRS _ \ Net X �1TVi1ERDRAIN� (T `• \`\ `\ .24•� \� .\ N\ \\ \\`� ,. JO i1 `\ `N\ ---?O\ _ NN.�N NN ��•�N.\ � -\ i ,\\\\ �• \\\ `\ \\♦ `\`\`\ - 71bC' 83 • 2 N N N\ 1 N\ \\\\\\ ��\ \` \ ` ���\ ! \` \���11$ \\ `\\ ` Ate`\\`\`\\�\ �! '\`�`\` \ '\�� \\`��\ 8385.0 \\�\�o \'�_� ���� I _ s ♦ ``\ \`\` ♦ ... \` �\`\`\ \`\ \ \ \ �"......2..,� \ \\ \, `�� X �\ \\ \�_-�\ 8372.6".° o `• 0\ `\ \• \\ `\ ‘`..,"*"\...„.„.'„\ \` ` \ 83 \5 `�\ \ 8379.1 /- `��\ ` \ ` \ X Y> *�` `�I f �EiCfQ�f\ ` \ `\ `\` \` Q J X \ \ \ I \„ p 4 \ \ •\ ` ` ``�\ `� \ 8381.2 \� / \.7C°\\\\• _ / / / �.I ` I I ` ` ` ` \ \ 'l \ \ \ \ \ \ 8371.1• \ \ \ \ \ \ \ �\ \\ \ ..... \ \ ` `�' `• ��\\`�\ `\ \ X \�„ `� o\\ I ``$372.8 \\ `\ \ `\ `\ `\ `\ N. \.„ , ...• \ ... 0 \ a \ I \ C \ s. • \\ \ \ `•\ • 8387.4 \ \ \ _ - -1 < \• \ Li, N. \ \ \ L9GV\ CK GAMS \ • `_ o • \ \ \ \ ---._::-. 348.:6,...:, \ �\ N. \\\\ A\ \ ` `l ` `\ /i�S O'er `� �\ ♦\ \ ISH\LL� r1�aCK D A � -, ` .-- `,.. �..\ \ ` `\\ `�\ �\\ \ \N ... \ X C \ \� 8388.8 /i ��- 372.7 \ \\\\`o I ` Wl `B,IOS,WAC AAL `\ `\ \` -- L WLrb \�� \�\\\ \` ` \\\ `\ ` `� \`�\�._�\\ \\ l �/! , 384.1 \�\ 1:::1 �� \\\ \\ \ \ /�-�`� `\ \� ` \` ''Ii�\ \ \ \ \ \ 8383.2 ` `y �♦ . \ ` \ '� DE QIIV'.� \"R� `\ ` \ -� -`,\ �+ Q O\ \ \ \ 1 \ ` XIT180 \ \ - r \ ` \ \ \ \ W CC 493+°° \\� \ \ \\\ \ \ \- gliN/ \ fc � / \ `� ` ^\ • \� I \ \ \ \\ \ \ • \ \ \ \ \ \ - \ O.(I) \ r\ \\ \ \ \ \ \ \ ,.....416,7,•' / • ��- \ /� \o \ ` `� 85.1 ` `\ `\ ` `� `\ `\ •.\ `\\ �+ //C i' 8342.4�` `\ `�\ \\` �� \ �-\j I s- - `�``\ \/coNc. i 8389.7 - \ �\ \�\\ \ \ / _\C\ \\ , X \\ ♦\ \�` �� \ \\\ \\ N�\ frill 0 . - \ . \- . __. 8 1:0 -4 \ • �- \ \�\ `\`` / _� N. •., X`\��-�/� 4111 /I `\ \ 8391.4 \\ \ \ \\ / ���� `\ ` �� \ `� u5 8343.7 /` \ 411% \ / \ \ \ \ \ ` ` \ \ o x e `` \ \\ \ `SC �SiaB \ / BIORETE -- IN ` \ ' \� .\)\ / \ ``\ \ \\ 8361.2 I / \ \\ ♦ _ I \ _ \ \ /� \ \ \ -Ln \ `\ \\\ \`,_8360.8 N..,„\f �n \\ / \\ •4, N4�L k C.'H`\ECK D. S\ \\ .���,, `\ ` `�\.��� `\ m l=/7 I \ 3' ` �� •' L RISER \ \` \ 8361.1 S ����'.�iilaT ; \ r,. `\ \ \\\ \\ .O \ .\ \ / J \ \.0 .� \ �\ ,�• ` lwd'�hJ BIOS AND \ _ • \ \ \ i I \ 4 AI"._ -a\N c,�* \\ I \,\ X \ S YP.) `\ / \� --- \ \`\�. X -------- eIN RAI1\l \ X • \ 11 S PIP �`,\\\ Q/y l\° \ • \ a.. ••� `\\ \\ �\ • / / \ `�\ \� \ ( \\ X -7l \ \ \\\\ \ of '\ \\\ \` \ \ I \ \ ` \ 83.44.6 \ \ "OVI i \ \\\ \ I \ ` - . \ \ \ \` `\ \`\ \ `\N PON \ ��i-Nom\ NN 8343.5 \ \ \ \\ ti/ \ \ \ \ \��/ i-- --� \ \` \ \N \\\Z 859.6 \ / � ) \ \\ \ \ \ \ \ \ ,\ i �, -, / \ \. C, X 1 : . •RET • \`,\y ,,,, x /-` \ / ,...2„,..\ \`�\` \ \ \ `\ / .� \ \ _ \ X�� N. \ \\ X 361.9 �\ / \ \ \ Ni \\ , I I ,\ \ / • \\ \ \ \ \ \ \ \ \ \ \ 8399.7 \ // • \ \ \\\\, \\i 8359.3 x J \` ` `N N�� `\\ ��\ ` `\ N �� ,I \\`=__� \\ i _ , \ 1 \ \ \ tip/ �'iJ \ \ / \ \ \ • \ \ \Alifr / ��� • \ \ , \ / `\835.5 \* \ \ ` �`\,`\��\\`\ \ N. N. / `� o \ , \ �i- \,\ \ "..N.,":\N. \\ \ \ i ,\ i • Q \ i 8347.3 \ '\ \ \ -...3•„„ N \ v"k , \ \ \ i • \ \ \ • ••• ••\`\ _ 60. \ I 1 �� \. 8354.5\ \\\ \ <14 \ \`�\\ \ / -- 11 ` N\`N N �N \ N` \ ` ` ' Q \ \ \ 1 �/ - \ \ \ / --J \ • • \\\•. GRA-PHI: SCA I •\ . - \ I ` \ \ \ \\` \ / w co W o �\\a\\\\ • 50 1\ • 10c 1 200 / -, \ ��\\\\\ /- \ / / \ \\\\ \\ l\ / � \\\\\ \,\\\\ I cri \� 8349.5 �_�___\ • •.L\\ \\\\ `\ \`�\``�V ���` L / ,�7I ---` ��\\\ SHEET 0 \ \- •\ - -_ •• X ` \\�---- - �\ \\ SMP - ---_ \\\`\`\ ittc)i "1OA\ft. -- •. • - _. _ _ `` \ \`----D_-----------:-"---. _ ` a. \ `� ! \` \ / I.1� ��\ ` ,\`\o p \ 8367.3 \\ \ ` \ ZIIIIIIIIIIIIIIIIIIIIIIIIIIZR � 7. Gore Creek Station 498+50, a z 'a• l Big Horn Road, 1-70 Exit 180. J III III „ Idi 41Iso IIII w ." Proposed BMP Recommendation: Forebay - ��� cp il8a and Bioretention (Rain Gardens) to provide - -• .. n_ - �� 141.11 _ :" i" ����w W o treatment and remove pollutants, including - ''r° �� . sedimentation, filtering, adsorption, �J-- - . - _ ,�-- 4.. evapotranspiration, and biological uptake of �� w ��.�n• �. _ s - --..1: = `3i"t .-. - _'• 4,......, -:..i . L w i -,.\ .•.: constituents. Check Dams with Bioretention ' - * : =;; E: _ . K ,.. , R Media and Underdrains. *ter;•... - _ „lit . �, . 18. r' _�V' --.7 �• ` '"�^ :Yrs.',.' lam. *"- "may' ■ 1 _-. --- ..� r • Pollutant Sources: Pollutant wash—off from _ -- -4-4=-,„--t- I-70 and Bighorn Road, sediment, cinders, _, •-� �,� �` ' ,� -'��: _ � � ., . . hydrocarbons, trace metals, road salt and ,Y: .; ..-74..-1:-� t ; deicing chemicals. J.y. Fa'S. -'o- zi..,4 _ ;:nr_F .,,;Sv - Property Ownership: CDOT a - Z Lat/Long: 39°38'40.19"N, 106°18'27.70"W F -.‘1.444. O Potential Permitting: CDOT, TOV •- � n 0 ° 6 , Potential Partnerin3 g: CDOT, TAP grant in -. •..u3 i , Q ..WZ 2017 Ali ._ . „Am. _ w , ., .: ,:.H .., Q� ..,.. a Estimated Cost: � - �. " � a Construction: $400,000 ., :.:,. a . 7•-,-• :`�°:' :ate- ' Vit,., iP` :- - U � M • Design and Permitting: $160,000 = .: K__ : r,Sn,. Ili _ 1wed - . __ It Total: X560,000 ,c: ; xr. � ' Notes: Bioretention, Bioswale, Check Dams ct , :, ` } ;r,>4 �5 r: O (1) L' and Forebay. �F.:.�: ,. :1. ;::' • . 06 r. Next Steps to Proceed to Preliminary Level: „. x Detailed Field Topography, Existing Utility .- - 0 Locates, Geotechnical Evaluation, `'°� � 0 Environmental Clearances, and engage CDOT in discussions. 6-, BIOSWALE SEDIMENT FOREBAY N Priority: Rated Level 1 because although FAST DRAINING BIOSWALE NOTES OSWALE ELEVATION SHALL BE MIN. 6" the area is pretty well stabilized and SOLID MIX TO INCLUDE BELOW THE LOWEST ADJACENT ELEVATION 1 /� o • 50%COURSE SAND 2. BIOSWALE SHALL NOT BE CONSTRUCTED vegetated with some impervious area, a • 20%PEAT MOSS UNTIL ALL CONTRIBUTING DRAINAGE AREAS L • HAVE BEEN STABILIZED z a • 30%SANDY LOAM •, p substantial amount of traction sand and I BIOSWALE 3. COORDINATE PERFORATED PIPE UNDER =11N d PLANTING DRAINAGE SYS MS WITH CIVIL DRAWINGS FOREBAY 5 m pollutants from roads were observed in the - TREATMENT BMP E N field without apparent treatment or SEE 'L RIPRA A ON a) — — — lip ��� — OR PLUNGE -OOL catchment and there appears to be space ...2) .--"----"--':* „.„.___....__-/----..---- to provide Forebays and Bioretention as i, l� _ d well as Check Dams with Bioswales. ,I—III= 111_111— �� —II III=111 =11110 111 II—III _II- -=----111-1=-, 111,- Z FAST DRAINING A • -a--I L.p II BIOSWALE SOIL d a °II— FOREBAY - TREATMENT BMP N 111 1— ° MIX 1 0• MIN. Q 1=III -3.0' MAX. _ - III 3:1 SIDE C 0 -, _ �-I HEADWALL(IF w III II -�a III II_, SLOPE MAX. o Q7 it III 1_�I=I\\- /REQUIRED)TREATMENT VOLUME wQ = r o ra - INFLOW AS SPECIFIED(SEE S DESIGN CRITERIA UNDISTURBED �= - CHECKRI )AM z z r z Cr73IO SUBGRADE - I / FRENCH DRAIN I- OREBAYI/ TREATMENT BMP o o 6 co o SYSTEM W/10” MESH �~ OR APRON � AND 4" PERF. PIPE 10 OR PLUNGE POOL 0 CI SHEET 5 8C H 0_ Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Appendix C Existing Site Photos Prepared by RESEPC, Inc. Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Exit 180 Site % I •41111100111111111111111111110.1111. ..-- .«-k- - - ' ' 4i,.._. ..i.,.., -74,1,-6 4 .. 71-I- i: - •. - r. JJ 4 Mi _ -- ___,_ •ti, -- . mi. .. Looking east at area between Big Horn Road Looking north across the WB I-70 on ramp and the EBI-70 on ramp toward the outer road i' - ' •' kli4ilto] ' ' • iiiltiii,i;ail , iii Vk,,,,..........-.14110! , .. ,i,e„MP '. ' . , , Looking east at the EB 1-70 on ramp from the Looking west along the WB I-70 on ramp north side of the on ramp '. r. A.: & ! .. - IQs •� .. �'iT.4'''P. .rel 'f' SPRINGS . Ev +. .... S i is - , -i , DENVER.II. - " • ' 'F' k 3;. r Looking north from the bottom of the EB I- 70 on ramp Looking east at WB I-70 off ramp Prepared by RESEPC, Inc. Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Snow Cast Off Area �,y� . V 7 .' ''' '. '.:7 ' 1 1W 1:1 ''''!IPI il 0 .. , C4 -- - ' I,,,,,,,,,,,, I ' L:' . , +. ,, ,.. ,_ , . .4,„:. " ' Looking toward Big Horn Road under the •�.••• .0...i. - - M., :.' -, " •r, ,�. WB 1-70 bridge Looking toward Upper Gore Creek&the EB 1-70 bridge from under the WB 1-70 bridge AL • y Looking at Upper Gore Creek&erosion of embankment under the WB I-70 bridge • S•. moi.._.._. � 4 1 Looking toward Upper Gore Creek&the EB 1-70 bridge from under the WB 1-70 bridge Prepared by RESEPC, Inc. Conceptual Alternatives Report 1-70 East Vail Landscape and Water Quality Improvements Truck Ramp Site . tom_ • AI r46 • ,:~ L.-4, �f 6... +['iii F, ,4-s!, ,i4 • ll • � lei tilligM Lookingeast at surface sediment basin off , the shoulder of WB I-70 " {' ate_ { ^, . Looking east at inlet in I-70 median Nti 1. .., _is.r l ..r..� ._n •iii ._ ; -- Looking east at inlet in shoulder of EB I-70 • ', —' IA-.p..• � 'iter. r 1�'' 'f.: -•. _ ;C. r,.. -•2 ►i.•"'mi: . •, C T....r .5_. Nef`. .. - ,-,:- t.:.e --Ar. 4. Looking east at inlet downstream of surface X . sediment basin off the shoulder of WB 1-70 _. •---- }''' ~ T Extreme erosion of Upper Gore Creek embankment off EB 1-70 shoulder Prepared by RESEPC, Inc.