Colorado Avenue Dam Proposed Paddle Trail Improvements Preliminary Design Report Deschutes River, Bend, Oregon

Transcription

1 Colorado Avenue Dam Proposed Paddle Trail Improvements Preliminary Design Report Deschutes River, Bend, Oregon Prepared For: Bend Metro Park and Recreation District 799 SW Colombia Street Bend, Oregon Prepared By: Gary M. Lacy, PE Mike Harvey, CFM, PMP Recreation Engineering and Planning. Boulder, CO (303) Final Draft October 2009 (303)

2 Table of Contents Introduction... 3 Background... 4 Hydrology... 9 Alternatives Analysis General Design Background Option Option Option Option Option 1A Analysis of Option 1, Option 1A, and Option Recommended Option Regulatory Issues and Permitting US Army Corps of Engineers: Oregon Department of Environmental Quality: Oregon Division of State Lands: City of Bend: Summary Table of Required Permits: ADA Accessibility Preliminary Cost Estimate Bibliography Appendix 1: Drawings Appendix 2: Ecological Assessment of the Proposed Colorado Avenue Dam Deschutes River Streambed, Prepared by Pacific Habitat Response to Above Report, Prepared by REP Appendix 3: Public Process Summary (303)

3 Introduction The purpose of the following report is to summarize the recommended preliminary design plan for recreation, environmental, and safety improvements at the Colorado Avenue Dam (See Figure 1). Recreation Engineering and Planning (REP) has been contracted by the Bend Metro Park and Recreation District (BMPRD) to complete a preliminary design for this site. The Colorado Avenue Dam was identified as a critical site for improvements during the Deschutes River Paddle Trail Feasibility Study, completed by REP in SECTION 1 Introduction and Background Figure 1: Colorado Ave. Dam The Colorado Avenue Dam emerged through the Paddle Trail planning process as the site with the most potential to meet the goals of the Paddle Trail Study and was selected as the first improvement project. Once the Colorado Avenue Dam site was chosen, multiple alternatives were considered for the site. This report summarizes REP s final recommendation as to which alternative would most effectively meet the goals of the community based on the criteria set forth in the Paddle Trail (303)

4 study, the information gathered during the process, and REP s professional opinion. Option 1A was selected as the best alternative to meet the needs of stakeholders. The following information was used to evaluate the options and includes, but is not limited to: 1. The public comment process, 2. Meetings with adjacent landowners, 3. Input from Bend Paddle Trail Alliance (BPTA), 4. Environmental Assessment completed by Pacific Habitat Services, Inc. (July, 2008), 5. Survey Data, 6. Anticipated Costs, 7. Safety, 8. Total footprint of the proposed improvement. Background The Colorado Avenue Dam creates an impoundment that was once used to support lumber mill operations. The impoundment currently maintains water surface elevations upstream in the Mill District area. Maintenance of this water surface elevation was a critical design constraint when alternatives were considered for modification of the existing dam. The dam is located in an area of the river that is heavily used during the summer months by people on inner tubes and other inflatable craft that require little skill to operate, thus exposing a high number of low skilled river users to the dangerous conditions. The dam and access bridge structure are an extreme hazard for every type of in stream user. The combination of the dam s low overhead clearance, multiple channel obstructions, loosely placed sieve boulders, and angle iron bridge supports create an entrapment and drowning hazard. The dam hazard has been documented by a fatal accident and numerous near miss incidents. The need for safety improvements at the Colorado Avenue Dam was identified and discussed in the Paddle Trail Study as a critical goal of the community. (303)

5 Figure 2: Ownership map of the area surrounding the Colorado Avenue Dam (303)

6 Figure 3: A bathymetric survey of the Deschutes River at the Colorado Avenue Dam was created for design purposes. The Colorado Avenue Dam is an obstruction to the upstream migration of fish and improved fish passage was identified as a design criteria. Additional environmental concerns included the maintenance and creation of spawning habitat, improvement of the aquatic habitat of the reach and improvement of the feeding grounds for the resident Osprey. A preliminary environmental analysis of the proposed concepts was completed by Pacific Habitat Services and (303)

7 REP completed a response. Both documents are attached in Appendix 2. It is recognized that additional environmental analysis will be required during final design development. Providing for non whitewater paddle craft, such as canoes, recreational kayaks, and inner tubes to safely travel between the Class I moving water sections above and below the Dam, was another objective that was identified in the Paddle Trail Study. In addition, the Colorado Avenue dam has sufficient head to create whitewater play features. Whitewater boating improvements appropriate for a variety of users including instruction, beginner to intermediate whitewater paddlers, and expert level park and play whitewater paddling were further identified as potential objectives for this site. Stakeholder Criteria COID Dam Healy Bridge Area Colorado Street Dam Bend Hydro Tumalo Dam and First Street Rapids North Unit Canal Dam BMPRD Addresses safety issue Associated with other District or City of Bend projects Completes a missing link that connects existing trail segments and parks Ease of implementation Relative level of use (user type and numbers) Environmental Improvement to fish habitat Improvement to natural appearance Recreational Users Instructional Opportunities Whitewater play features Accomodates users over wide range of flows Spectators Provides sufficient seating and view of the river total Priority matrix used to determine which sites could provide the greatest benefit to residents of Bend. Each site was scored on a scale from 0 to 5, where a score of 0 indicates no benefit or no improvement in that catgory and 5 indicates the highest benefit or greatest improvement in that category, relative to the other sites. Figure 4: This priority matrix was developed during the Paddle Trail Study (2007) and identified the Colorado Avenue Dam as the highest rated site for improvements. (303)

8 Figure 5: View of the Colorado Avenue Dam looking upstream from the river right bank Figure 6: This artist s rendering for the Colorado Avenue Dam illustrates the general concept proposed for safety and habitat improvements, in the 2007 Paddle Trail Feasibility Study. (303)

9 Hydrology In the reach where the Colorado Avenue Dam is located, The Deschutes River exhibits a very stable flow regime that provides sufficient flow for recreation throughout the year. The Deschutes River is subject to seasonal flooding, however flood flows rarely exceed the monthly mean flows for June and July, shown in Figure 7. The Flood Insurance Study(FIS) for Deschutes County (FEMA, 2007) notes that the flood of record for the Deschutes River was 2,280 cubic feet per second (CFS) while the one percent chance (100 yr.) flood flow is 2,685 cfs. It is recognized that additional hydrologic and hydraulic analysis may be required during final design, such as impacts to the regulatory flood elevations (base flood elevations) through the site. However, the currently proposed design alternatives are all engineered to withstand the additional scour potential that flood events create. Figure 7: Hydrology of the Deschutes River through Bend (303)

10 Alternatives Analysis Three primary options were originally considered for the Colorado Avenue Dam and a fourth option was proposed by REP based on feedback during the spring of These options are labeled Option 1, 2, 3, and 1A, respectively. The original three alternatives were presented in January of 2008 to local stakeholders and the public while the fourth option included recommendations from REP s 20 years of experience with similar projects and additional concerns raised during the design process. All options could be implemented such that they would have no negative impact on the upstream impoundment elevation and would provide for safer passage through the dam. Additionally, all options include removal of the existing pedestrian bridge and replacement with a new, higher pedestrian bridge, with one bridge pier attaching to a constructed island in the dam. SECTION 2 Alternatives Analysis In May 2009 an additional safe passage only option was requested by the district in order to provide an additional alternative and to evaluate the incremental cost of the proposed whitewater play features described in the original four options. For simplicity, this option was labeled Option #4. (303)

11 General Design Background With dam improvement projects there is an opportunity to create a step pool or pool drop configuration where the hydraulic fall of the dam is distributed over a longer stretch of stream through a series of drop structures with downstream plunge pools (shown in Figure 8). In the proposed design alternatives this is referred to as the Whitewater Channel. This type of design is most often implemented when whitewater features are a desired goal. This design has the additional benefit of creating habitat diversity, increasing fish passage opportunities, and creating overwinter holding areas for aquatic species. The second type of dam modification is referred to as a bypass channel (shown in Figure 8). In this case the hydraulic fall of the dam is distributed evenly over a longer reach of stream. This type of improvement is most often implemented when the desired design goal is to more evenly distribute velocities along the reach to allow for fish passage opportunities of less vigorous species and create a safe moving water/class I boat passage through a dam. The channel can be configured a number of ways to include riffle/pool sequences and increased habitat diversity along the reach. Offset velocity shelters can improve the ability of boats to pass the dam safely and create feeding lane for fish species. (303)

12 Figure 8: The two profiles describe both the bypass and whitewater channel concepts. This drawing can be found in Appendix 1. All options include a flood resistant, river right concrete trail underpass under the Colorado Avenue auto bridge. This underpass must have a minimum of seven feet of overhead clearance between the low chord of the Bridge and the trail surface and meet ADA requirements on all approaches. The trail includes a wetland boardwalk to provide public access to the adjacent wetland but does not continue downstream past the proposed pedestrian bridge. All options also include improvements to an existing gravel trail located on the river left. This trail has historically been used to portage around the existing dam. The new trail will include a trail underpass under the Colorado Avenue auto bridge that also meets ADA requirements. (303)

13 The proposed replacement pedestrian bridge is envisioned as a pre engineered steel pedestrian bridge with a 1% arch and a center pier. This new bridge will create appropriate overhead clearances for river users and be of sufficient width to accommodate trucks and vehicles. The bridge will be engineered for 10,000lbs loads. Option 1 Option 1 proposed three channels across the crest of the dam face as shown in Figure 9. The river right channel (as looking downstream) was designed as a gradually dropping habitat protection area. The area was designed to create additional habitat area to address landowner concerns associated with an Osprey nesting area located on the river right bank in the figure. No improvements or impacts would affect the river right bank near the nesting area. The habitat area would not be designed for boaters and would be mostly inaccessible. The center channel was designed as a safety bypass/fish passage channel using a step poolriffle configuration. The channel contained three refuge areas for boaters and velocity shelters that would provide areas for fish to recover during upstream or downstream travel. The refuge areas could also serve as locations for boaters to retrieve river craft and gear if mishaps were to occur during navigation. The safety bypass/fish passage channel would contain smaller drops and pools primarily designed for habitat enhancement as well as small drop pool riffle sequences with recreational value for beginner to intermediate boaters. Lastly, both banks on the center channel would be designed to withstand flooding and serve as an island to delineate the channels and enhance the habitat within the project area. The river left channel was designed as a whitewater boating channel composed of three drop structures in a step pool configuration. Drop #1 is the signature whitewater feature composed of a dynamic 2 foot drop with possible adjustable whitewater enhancement features. Drop #2 is an intermediate drop that would offer freestyle kayaking for a wide range of boaters. Drop (303)

14 #3 is a gentle whitewater feature for all abilities and is located a short distance from the existing beach at McKay Park. The riparian vegetation located on the left bank would be preserved. This option was favored by the recreational boating community who felt that the segregation of uses between less skilled and more highly skilled users was critical. Option #1 meets all of the stated goals of the improvement project however also raised a number of concerns. The footprint of this option is very large, the entire width of the river was utilized and the safety channel and whitewater channels occupied over 70% of the total channel width. Specifically, the option created concerns for stakeholders because of potential impact to the resident Osprey nest and in stream habitat, including trout spawning beds located in the river right channel. The large footprint of the proposed configuration of Option 1 raised concerns that increased recreational activity would be drawn too far to the river right side of the channel. Figure 9: Option 1 (303)

15 Option 2 Option #2 proposed three channels in a configuration very similar to (Option #1). The river right channel would be constructed similar to Option #1 with a gradually dropping habitat protection area but with a greater overall cross sectional width. The center channel would be constructed as a safety bypass/fish passage channel in a drop pool riffle sequence. The center channel would merge with the whitewater channel above drop #3 near the existing beach at McKay Park. This intersection of channels would allow a greater volume of flow for the bottom whitewater feature and reduce the overall footprint of the in stream improvements. Additionally this configuration would funnel all recreational use further away from the river right habitat area. Option 2 was eliminated due to the concern that the combination of potential user groups at the confluence of the center and left channels would lead to conflicts. (303)

16 Figure 10: Option 2 Option 3 Option 3 shown in Figure 11 proposed two channels, while deleting the independent safety bypass/fish passage channel. The option was created as an attempt to maximize the size of the habitat protection area near the river right channel and minimize the potential impact to the portion of the channel dedicated to habitat. Although this option would create a sizeable habitat area near the right bank, it would funnel all recreational users into the same channel. There was concern that this mixing of uses would lead to user conflicts and would not fully meet the objectives of the project. The riparian habitat and existing vegetation on both the left and right banks would be preserved. Option 3 was rejected by the stakeholders because of the lack of a segregated safety bypass for recreational boats not interested in a whitewater experience. There was an additional concern (303)

17 that the combined channel would prevent paddlers from attaining the dam, i.e. paddling upstream from the bottom pool to the upstream impoundment. Figure 11: Option 3 Option 4 Option 4 is an alternative that provides a safety bypass only and thereby evaluates the incremental cost and impacts of the proposed whitewater play features described in option 1A. This option is shown in Figure 12 and is similar to Option 1A, but without the whitewater channel in the center channel. The option includes no impact, construction, footprint affects, or construction equipment in the vicinity of the Osprey habitat, and all channel modifications near the right bank and center of the channel have been deleted. The entire footprint of the proposed improvement was shifted towards the river left to maximize the buffer zone between recreational use and the existing in (303)

18 stream and riparian habitat on river right. No channel modifications for recreation, safety, habitat enhancement, or fish passage are proposed in the right or center channel. In the option, the existing crest elevation of the Colorado Street dam will be maintained to retain the pool elevation above the dam and distribute water through the cross sectional area as designed. Rebuilding the dam, which includes a concrete cutoff wall, additional divider wall material, and scour protection at the base of the drop above the habitat area, are included in this option. The river right and center of the river will include a trickle down boulder cascade designed to maintain the hydrology in the vicinity of the habitat area and maintain adequate flow in the potential spawning beds. This design maintains the flow regime in the river right and center channels but increases the risk of drawing kayaks, canoes, and inner tubes over the boulder cascade. This design also reduces the volume of fill required and thus the resulting construction costs. Additionally, the construction footprint will be slightly less than that created in Option 1A. The river left channel is designed as a safety bypass/fish passage channel. This channel will be used to accommodate safe passage of the dam for all river users. Based on stakeholder concerns, the safe passage channel is located on the left bank to alleviate the concern of users impacting the river right habitat area. Additionally, this configuration places the bypass channel adjacent to the left bank in order to make it more convenient to access the portage path that is also provided for the less skilled users. (303)

19 Figure 12: Option 4 Option 1A Option 1 shown in Figure 9 matches the needs and objectives of the majority of river users. However the large total footprint of the improvement created concerns about the impacts to the river right spawning beds and in stream habitat. In response to these concerns REP created a fifth option, Option 1A shown in Figure 13. The option includes no impact, construction, footprint affects, or construction equipment in the vicinity of the Osprey habitat and all channel modifications near the right bank have been deleted. The entire footprint of the proposed improvement was shifted towards the river left to maximize the buffer zone between recreational use and the existing in stream and riparian habitat on river right. No channel modifications for recreation, safety, habitat enhancement, or fish passage are proposed in the right channel. (303)

20 In all proposed alternatives, Including Option 1A, the existing crest elevation of the Colorado Street dam will be maintained to retain the pool elevation above the dam and distribute water through the cross sectional area as designed. In Option 1A, the river right side of the river will include a trickle down boulder cascade designed to maintain the hydrology on the vicinity of the right habitat area and maintain adequate flow in the potential spawning beds located in the river right channel. The crest of the boulder cascade is located at an elevation such that water flows between the boulder during normal flows, but not over the crest of the dam. This design maintains the flow regime in the river right channel without introducing the risk of drawing kayaks, canoes, and inner tubes over the boulder cascade. This design also reduces the volume of fill required and thus the resulting construction costs. Additionally this solution for the habitat channel minimizes the impacts to the existing geomorphology of the river right channel. The center channel is designed as the whitewater channel with drop #1 being a dynamic 2 foot drop with modular whitewater enhancement features. The width of the channel has been decreased in order to reduce to overall footprint of the modification. The river left channel is designed as a safety bypass/fish passage channel. This channel will be used to accommodate safe passage of the dam for beginner to intermediate boater and tubers. Based on stakeholder concerns, the safe passage channel is located on the left bank to alleviate the concern of tubers impacting the river right habitat area. Additionally, this configuration places the bypass channel adjacent to the left bank in order to make it more convenient to access the portage path that is also provided for the less skilled users. (303)

21 Figure 13 Option 1A (303)

22 Analysis of Option 1, Option 1A, and Option 4 Design Consideration Option 1 WW left bank Center safety channel Roughened right channel large footprint Option 1A WW center Safety channel left No right channel overall smaller footprint Option 4 No WW channel Safety channel left No right channel Smallest footprint Directing Tubers to Correct Channel Currently tubers are conditioned to move left for portage. Aligns with the upstream portage takeout. Easier for tubers to reach and get out at the McKay Park beach. Aligns with the upstream portage takeout. Easier for tubers to reach and get out at the McKay Park beach. User friendly for low skilled users User friendly for higher skilled users Upstream movement for paddlers Habitat impact, left bank If floating down the center, easier to stay center. Places whitewater channel next to park for increased access for park and play. Larger footprint allows for longer, flatter overall slope, reducing velocities and increasing likelihood that upstream movement is possible. Whitewater channel could step down more quickly and mimic existing bank more closely. May be slightly more difficult for low skilled users to move left. May result in more tubers inadvertently using whitewater channel. Kayaks and canoes can be easily maneuvered out to center channel with moderate skill set. May still be possible with careful design. Potential for more bank disturbance with a more gradual left channel resulting in higher relative water surface elevations on the upstream end. May be more difficult for low skilled users to move left to the entrance to the bypass channel. Navigational passage only. No whitewater recreation. May still be possible with careful design. Potential for more bank disturbance with a more gradual left channel resulting in higher relative water surface elevations on the upstream end. Habitat impact, right bank Proximity of pools and drops may encourage entry from the bank. Park and play use furthest from osprey. May result in some tubers using right bank for exit if they can t make it left to portage path. Potential for more tubers to exit river along the bank. No impact with elimination of right habitat channel. Smaller overall footprint than option 1. Potential for more tubers to exit river along the bank. No impact with elimination of right habitat channel and center whitewater channel. (303)

23 Safety for lesser skilled users Users desiring portage must exit river well in advance of left channel. Safety channel and portage trail on same side. Safety channel next to park may enhance safety for park/river interface. Safety channel and portage trail on same side. Not as safe as options 1 and 1A, due to the fact that users might be pulled over the dam. Safety for WW paddlers Spectator ease Play features for whitewater boats Trail connections land Constructability Fish passage Habitat impact riverbed Same set of potential risks for all three options. Safety and rescue from McKay Park. Closer to whitewater boaters from McKay Park side. Equal viewing opportunity from pedestrian bridge. Equal potential for whitewater as Option 1A. Larger footprint = more space to accommodate boaters. No change between alternatives. Larger overall footprint. More material = comparable cost. Technically very little difference. All three alternatives offer improvement of upstream fish passage. All three alternatives offer improved instream habitat. River right habitat channel offers larger habitat improvement. Same set of potential risks for all three options. Safety and rescue access incorporated into new pedestrian bridge and separator island. Equal viewing opportunity from pedestrian bridge. Equal potential for whitewater as Option 1. Smaller footprint = less space to accommodate boaters. No change between alternatives. Smaller overall footprint. Less material = comparable cost. Technically very little difference. All three alternatives offer improvement of upstream fish passage. All three alternatives offer improved in stream habitat. Eliminating the right channel reduces the overall habitat values. Same set of potential risks for all three options. Safety and rescue from McKay Park. Equal viewing opportunity from pedestrian bridge. Not included in this option. No change between alternatives. Smallest overall footprint. Approximately 11% less than Option 1A. All three alternatives offer improvement of upstream fish passage. All three alternatives offer improved in stream habitat. Eliminating the right channel reduces the overall habitat values but eliminating the center channel increases the overall habitat value. Costs Similar to Option 1A Similar to Option 1 Approximately 11% cheaper than other two options Figure 14: Colorado Avenue Dam Sub-Alternative Analysis (303)

24 Recommended Option Based on the provided options, matrix analysis, feedback during the public process, safety, costs, environmental enhancement, and REP s experience with projects of this type, REP recommends Option 1A. REP believes this option considers all concerns raised, meets stakeholder goals and objectives, and is the preferred alternative for the following reasons: This option provides the most safety for all users, particularly unskilled paddlers, inner tubers, and similar craft. This option provides for passage without the chance of anyone being swept over the dam. This option eliminates the lack of overhead clearance, and body and leg entrapment potential (similar to the other options). This option provides multiple options for fish passage. This option increases recreational options for multiple users including downstream and upstream passage of watercraft, inflatable and inner tube downstream passage, whitewater recreation, freestyle kayaking, and multiple habitat features for fishing enhancement. This option provides for segregation of users. The multiple channels allow for tubers and other non skilled craft to proceed downstream separate from the more dynamic whitewater channel. This option preserves the right bank and Osprey nesting area with a large undisturbed habitat protection area. The overall footprint is greater than option 4, but it provides more benefits. This option provides for easier access to the portage and access to the entrance of the navigational channel on the left bank. It enhances trail connections, viewing opportunities and the portage route. This option maintains the upstream pool elevation (similar to the other options). This option is more expensive than option 4 but also provides more benefits. (303)

25 Regulatory Issues and Permitting The proposed improvements are subject to the Clean Water Act which is administered through the Federal Section 404 permit and State 401 water quality certification. Work above the bank would be reviewed by Oregon Parks and Recreation Department, and work below would be reviewed by the Oregon Department of State Lands (DSL), The Oregon Department of Environmental Quality and the Army Corps of Engineers. Additional local permitting would be required by the City of Bend. Permitting for the proposed project will require extensive coordination between all of the identified agencies and the BMPRD. A pre application meeting involving all of the various agencies may be advisable as a means to streamline communications between the BMPRD and regulatory representatives. US Army Corps of Engineers: The Clean Water Act gives regulatory authority to the US Army Corps of Engineers for all navigable waters of the US. All temporary and permanent fill placed below the Ordinary High Water Line (OHW) is regulated through the US Army Corps of Engineers, Section 404 permit. Bend is in the Portland District of the USACE. There are typically two categories of 404 permits; Individual and Nationwide. Nationwide permits are available for certain common types of projects which have a smaller overall impact and smaller quantities of fill. The proposed project will, in all likelihood, be considered an Individual Permit. Individual Permits can be a lengthy process from the pre application process to execution of a signed permit. An Individual Permit acts as a comprehensive environmental review of a project. Typically an Individual Permit submittal involves the preparation of a lengthy report which documents the existing conditions at a given site and then assesses the potential impacts of a proposed modification. Alternatives Analysis, work area isolation methods and fish passage documentation are some of the critical components of the 404 permit in Oregon. The Individual Permit typically includes consultation with additional federal and State agencies which may include, but not be limited to: (303)

26 Local Tribal Governments and/or Oregon State Historic Preservation Office US Fish and Wildlife Service Oregon Department of Fish and Wildlife It is recommended that additional design consulting also be undertaken with the local environmental community before submittal of the required 404 permit application. In Oregon a joint application for Removal Fill is submitted to both the US Army Corps of Engineers and the Oregon Division of State Lands. The instructions for this application are located at the following web address: In the case of the proposed Colorado Avenue Dam modifications an additional permit may be required to dredge or expose the sediment behind the dam. This will permit may or may not be applicable and will depend on the dewatering method determined during the final design process. The Sediment Evaluation Framework includes the preparation of a Sampling and Analysis Plan (SAP), which identifies and evaluates the potential hazardous elements within the sediment at the Colorado Avenue Dam. This plan addresses how a given project will handle and manage the sediment and any potential dredging that may have to occur. The document discussing this submittal is over 300 pages long and can be found at the following link: Oregon Department of Environmental Quality: The Oregon DEQ oversees the State portion of the Clean Water Act, the 401 Water Quality Certification. In the case of an Individual 404 Permit in the State of Oregon there is no additional permit submittal; the materials submitted to the US Army Corps of Engineers are forwarded to the Oregon DEQ once the 404 permit is deemed complete and ready for public comment by the USACE. This review process should be more or less concurrent to the 404 permit process and thus should not increase the overall time required. (303)

27 When more than an acre is disturbed by a project seeking a Joint Removal Fill permit the Oregon DEQ requires a 1200 C permit. The 1200 C permit addresses stormwater management, sediment and erosion control and a Land Use Compatibility Statement. The 1200 C permit requires an applicant to detail the Best Management Practices (BMP s) for a given project. The Land Use Compatibility Statement (LUCS) must be signed by a local planning department and demonstrates that project seeking authorization from the DEQ is consistent with local comprehensive plans. The guidelines for this permit submittal are located at the following link: Oregon Division of State Lands: The joint Removal Fill permit is detailed above and is the required permit for work on the submerged lands of the State of Oregon. City of Bend: The Water Overlay Zone (WOZ) is the portion of the City of Bend Development Code which pertains to development within the zoning area surrounding the Deschutes River. There are four sub zones within this zoning boundary: 1. Riparian Corridor 2. Deschutes River Corridor Design Review 3. River Corridor Areas of Special Interest 4. Floodplain The proposed project is located within the channel of the Deschutes and as such falls within all of these sub zones as they are defined. The majority of the WOZ code deals with land based development within this zone. The required elements of the WOZ permit application are similar to the application requirements for the Federal and State applications. These WOZ (303)

28 submittals are reviewed either at the staff level and/or by the full City of Bend Planning Commission. The City of Bend is the Floodplain Administrator for the FEMA Flood Insurance Program within the City of Bend. The WOZ application also contains a floodplain permitting process. The City of Bend requires an applicant to demonstrate no negative impact to the Base Flood Elevations (BSE) as determined on the updated flood maps for the City of Bend dated, September 28, In order to demonstrate that the proposed design does not create a rise in the BSE a one dimensional, HEC RAS flood model will have to be created or the proposed design will need to be modeled in the existing model of record; if that model can be located and obtained. The WOZ code is located in Chapter of the City of Bend Development Code (pages ) and can be found at the following link: ment_code_08_06_08.pdf Summary Table of Required Permits: Agency Required Permit US Army Corps of Engineers Joint Removal Fill Application Oregon Division of State Joint Removal Fill Lands Application Oregon DEQ 401 Water Quality Certification (Same submittal as above) Oregon DEQ 1200 C Permit (303)

29 City of Bend WOZ Water Overlay Zone ADA Accessibility All put ins, take outs and portage routes should be constructed in such a way that they are ADA accessible. SECTION 3 Costs Preliminary Cost Estimate The preliminary cost estimate includes two estimates. The first estimate is for the recommended Option 1A. The second estimate is for Option 4 which was requested by the District to quantify the costs associated with the addition of the whitewater channel shown in Option 1A. The costs associated with Option 1A are shown in Figure 15 and Figure 16 and total 1.72 million. The costs associated with Option 4 are shown in Figure 17 and Figure 18 and total 1.53 million. Comparing the two cost estimates shows that the costs associated with Option 4 are approximately 11% lower than the costs associated with Option 1A. Costs are offered based on recent market values for similar materials or work items. The cost estimate makes several assumptions that may prove incorrect after the bidding process is completed. The costs can be affected by presently unknown regulatory permitting conditions. (303)

30 The costs associated with the demolition of the existing pedestrian bridge assume an offsetting cost associated with recycling the steel. The cost assumes that an estimated quantity of stone (1300cy) is within the current Colorado Ave. dam and can be utilized in the proposed design. A contingency of 15% is contained in the estimate to account for assumptions. At this level of design the total cost is assumed to be within the range of 5%+10%. (303)

31 Colorado Avenue Dam Safety Improvement-Option 1A Preliminary Cost Estimate Item # Description Instream improvements: Estimated Quantity Unit Unit Price Item Total Price 1 Mobilization L.S. L.S. $20,000 $20,000 2 Water Control (During low-flow) breach dam, construct coffer dam, pumping. L.S. L.S. $120,000 $120,000 3 Acquisition, placement and handling of grouted stone in whitewater channel and divider walls 4525 Cubic Yards (CY) $85 $384,625 4 Acquisition, placement, and shaping of bypass channel, compacted stone fill 1400 Cubic Yards (CY) $85 $119,000 5 Acquisition, placement and handling of grouted stone in the habitat area 275 Cubic Yards (CY) $85 $23,375 5 Concrete Grout (whitewater channel, divider walls, overflow crest at river right habitat area) 1000 CY $180 $180,000 6 Acquisition and placement of Buoys 10 each $1,100 $11,000 7 Signage 2 each $1,250 $2,500 Figure 15: Cost Estimate Option 1A (303)

32 Pedestrian and Trail Improvements: 1 Mobilization L.S. L.S. $20,000 $20,000 2 Demolition/recy cling of existing pedestrian bridge and structure Loader-90 hours hours $120 $10,800 Excavator-180 hours hours $160 $28,800 Truck-80 hours hours $100 $8,000 3 Concrete Bridge Abutments, Center Pier, Concrete wing walls & retaining walls 2 ABUTMENTS- 30 cubic yards of fill per abutment CENTER PIER- 40 cubic yards of fill per pier Cubic Yards (CY) Cubic Yards (CY) $700 $42,000 $700 $56,000 4 Pre-engineered pedestrian bridge L.S. L.S. $160,000 $160,000 5 Backfill, grading & trail approaches 2000 Cubic Yards (CY) $40 $80,000 6 Trail Underpass 250 L.F. $180 $45,000 7 Trail landscape, restoration & signage L.S. L.S. $15,000 $15,000 Subtotal for trail and pedestrian improvements= $465,600 Subtotal Colorado Avenue Dam Improvements= $1,326,100 Contingency 15% $198,915 Design and Permitting 15% $198,915 Total= $1,723,930 Figure 16: Cost Estimte Option 1A: continued (303)

33 Colorado Avenue Dam Safety Improvement-Option 4 Preliminary Cost Estimate Item # Description Instream improvements: Estimated Quantity Unit Unit Price Item Total Price 1 Mobilization L.S. L.S. $20,000 $20,000 2 Water Control (During low-flow) breach dam, construct coffer dam, pumping. L.S. L.S. $120,000 $100,000 3 Acquisition, placement and handling of grouted stone in divider wall 2400 Cubic Yards (CY) $85 $204,000 4 Acquisition, placement, and shaping of bypass channel, compacted stone fill 1400 Cubic Yards (CY) $85 $119,000 5 Acquisition, placement and handling of grouted stone in the habitat area 1225 Cubic Yards (CY) $85 $104,125 5 Concrete Grout (whitewater channel, divider walls, overflow crest at river right habitat area) 840 CY $180 $151,200 6 Acquisition and placement of Buoys 10 each $1,100 $11,000 7 Signage 2 each $1,250 $2,500 Figure 17: Cost Estimate: Option 4 (303)

34 Pedestrian and Trail Improvements: 1 Mobilization L.S. L.S. $20,000 $20,000 2 Demolition/recy cling of existing pedestrian bridge and structure Loader-90 hours hours $120 $10,800 Excavator-180 hours hours $160 $28,800 Truck-80 hours hours $100 $8,000 3 Concrete Bridge Abutments, Center Pier, Concrete wing walls & retaining walls 2 ABUTMENTS- 30 cubic yards of fill per abutment CENTER PIER- 40 cubic yards of fill per pier Cubic Yards (CY) Cubic Yards (CY) $700 $42,000 $700 $56,000 4 Pre-engineered pedestrian bridge L.S. L.S. $160,000 $160,000 5 Backfill, grading & trail approaches 2000 Cubic Yards (CY) $40 $80,000 6 Trail Underpass 250 L.F. $180 $45,000 7 Trail landscape, restoration & signage L.S. L.S. $15,000 $15,000 Subtotal for trail and pedestrian improvements= $465,600 Subtotal Colorado Avenue Dam Improvements= $1,177,425 Contingency 15% $176,614 Design and Permitting 15% $176,614 Total= $1,530,653 Figure 18: Cost Estimate: Option 4 continued (303)

35 Bibliography Pacific Habitat Services, Inc. Ecological Assessment of the Proposed Colorado Avenue Dam-Deschutes River Streambed Improvements in Bend, Oregon. July, PHS Project Number SECTION 4 Bibliography (303)