site visit and conceptual design...

1 318 McConnell Drive | Lyons, CO | 80540

Site Visit and Conceptual Design Study Woodfin Whitewater Wave Woodfin , N.C. September, 2016 Prepared for: Advocates for the Woodfin Whitewater Wave Town of Woodfin Prepared by: Scott Shipley, P.E. S2o Design and Engineering 318 McConnell Drive Lyons, CO, 80540


Executive Summary The Town of Woodfin Is underway with visionary plans to revitalize its riverfront with construction a greenway, improved access to and utilization of the French Broad River by a broad range of users, and by adding a new park fronting the river near Silverline Plastics. The Advocates for the Woodfin Whitewater Wave and the Town of Woodfin commissioned S2o Design and Engineering to perform a site visit and conceptual study to determine the feasibility of installing a safe and enjoyable whitewater feature as a possible enhancement to that revitalization plan. Towns that have installed well-designed in-stream whitewater features have shown that the a project like the one being considered at Woodfin can add strong recreational appeal to active users of varying skill levels and add tremendous spectator interest from shore. This is especially true when the whitewater venues are located alongside public parks that include connected trails and greenways, parking, restrooms, and other amenities. The entire package of improvements being contemplated by Town leaders and advocates, including a whitewater feature, should significantly enhance appeal of the Woodfin riverfront.

S2o Design identified three potential project sites for the whitewater project: at the existing Riverside Park, at the proposed Silverline Park, and just below the Craggy Dam. It was found that it is feasible to design and install whitewater features at each of the project sites, with the designs varying in complexity and cost in order to adapt to conditions at the sites and assure no increased risk during major flood events. Specific designs were developed for each site, with preliminary opinions of probable costs formed for each design option. The Riverside Park location was identified as the preferred location due to anticipated favorable hydraulic conditions for the creation of a whitewater feature, its location next to the Riverside Park whose existing infrastructure would be complemented by in-stream recreation, as well as the ability to site the structure immediately above the pool created by Craggy Dam which enhances user safety. Additionally, the Craggy Dam likely results in a backwater flooding behavior indicating that a natural fixed grouted rock structure could be installed with a No-Rise Certification rather than requiring a mechanical Obermeyer articulating structure, reducing costs and improving aesthetic appeal substantially. Two designs are considered at the Riverside Park site – the more natural fixed rock and grout structure (preferred) at an estimated total project cost of $1.6 million, and in the event it would be required in order to meet flood-safety requirements, a mechanical Obermeyer gated structure at $2.4 million. The Silverline site is anticipated to require an Obermeyer gated structure in order to meet flood safety requirements, and project cost there is estimated at $2.0 million. A conceptual design for a continuous whitewater recreation channel was developed for the site just downstream of Craggy Dam. It would be a significantly more complex structure with project cost of $8.0 million, exclusive of parking and other associated amenities that would be required. Project advocates have made it clear that this whitewater channel alternative below Craggy Dam is not likely to be actively considered as currently feasible, but it might in the long-term future.

Federal regulations and required permitting will not allow any design or project to result in increased flood impacts during major flood events. Flood studies and detailed project modeling will be used to assure that any project selected will meet the rigorous flood permitting requirements of FEMA and the US Army Corps of Engineers.


With each design recommended for consideration at the Riverside and Silverline Park sites, a whitewater wave would be created that would be exciting and enjoyable to a broad range of users. As the flow characteristics of the French Broad River offers relatively large flow rates, the creation of a larger and more appealing wave is possible, making this a substantial attraction to the river community. By-pass channels can be included as well as convenient on-shore access ramps and paths to assure that novices can enjoy the outdoor recreation in a safe and enjoyable environment. S2o has extensive experience designing whitewater waves and whitewater parks worldwide, and believes that Woodfin has the opportunity to create a truly world-class whitewater amenity.

The Conceptual Design study found that the creation of a Woodfin Whitewater Wave is feasible with the Riverside Park site being the preferred alternative, and a draft timeline of the proposed project is included herein.


Contents Executive Summary ....................................................................................................................................... 2

Introduction: ................................................................................................................................................. 6

Section 1: Whitewater Parks ......................................................................................................................... 7

Whitewater Parks Defined ........................................................................................................................ 7

The Whitewater Design Process ............................................................................................................... 8

Design Factors for Whitewater Facilities: ............................................................................................... 10

Stability ............................................................................................................................................... 11

Costs .................................................................................................................................................... 11

Typical Economic Impacts of Whitewater Parks ..................................................................................... 12

Section 2: Site Information ........................................................................................................................ 12

Woodfin and Asheville, NC ..................................................................................................................... 12

The Study Reach: ..................................................................................................................................... 13

Channel Morphology .................................................................................................................................. 15

Flow information:.................................................................................................................................... 16

Flood Modeling Within the Reach ...................................................................................................... 19

Project Sites ............................................................................................................................................ 19

Woodfin Riverside Park Site ................................................................................................................ 19

Proposed Silverline Park Site .............................................................................................................. 24

Additional Considerations ....................................................................................................................... 27

Historic Structures .............................................................................................................................. 27

Endangered Species ............................................................................................................................ 27

Section 3: Proposed Improvements ........................................................................................................... 29

Project Objectives ................................................................................................................................... 29

The Woodfin Riverside Park Site ............................................................................................................. 30

Conceptual Design .............................................................................................................................. 30

Design Functionality ............................................................................................................................ 33

Opinion of Probable Costs .................................................................................................................. 36

Proposed Silverline Park Site .................................................................................................................. 37


Design Functionality ................................................................................................................................ 39

Costs of Construction: ......................................................................................................................... 43


Physical Modelling .................................................................................................................................. 44

Section 4: Process and Permitting .............................................................................................................. 44

Process .................................................................................................................................................... 44

Federal and State Permitting: ................................................................................................................. 44

Buncombe County:.................................................................................................................................. 45

Town of Woodfin: ................................................................................................................................... 45

Construction Requirements Analysis: ..................................................................................................... 45

Other Construction Issues: Endangered Species Act: ........................................................................ 46

Site Evaluation ............................................................................................................................................ 47

Conclusion ................................................................................................................................................... 48

Appendix A: Additional Alternative Designs ............................................................................................... 49

Riverside Park Dual U-Structure ............................................................................................................. 49

Riverside Park Articulating Structure ...................................................................................................... 52

The Craggy Reservoir Dam Site (Metropolitan Sewer District Dam) ...................................................... 55


Opinion of Probable Cost .................................................................................................................... 61

Appendix B: Buncombe County Permitting Checklist ................................................................................. 62

Appendix C – Preliminary Schedule and Associated Costs ......................................................................... 70

Bibliography ................................................................................................................................................ 75


Introduction: The Town of Woodfin is located just north of Asheville in North Carolina. The region was formerly a center of industry and commerce with ties to the Vanderbilts. Following an era of industrial decline, the city has experienced a shift in business practices, becoming a mountain destination in the heart of the Appalachians. Asheville’s city center is now a tourist destination with walking malls, boutique restaurants and revitalizing the Arts district. Continuing from this, the Town of Woodfin and the City of Asheville is aiming to grow its reputation as a destination for active outdoor recreation. The city developed a series of greenways and parks creation along the French Broad River. These greenways will soon extend down the French Broad and create a connection to Woodfin along the river, while Woodfin’s own greenway will extend to meet Asheville’s with the Town currently building a second town park along the river. There is interest in including a whitewater park in either the old, or new, Town Parks in order to create an anchor attraction that draws visitors north from Downtown Asheville.

Whitewater parks are community parks that are centered on the river. The parks include waves, eddies, and other features that are attractive to in-stream users to pursue recreational kayaking, surfing, and floating. These parks, surrounded by trails and recreational areas, have not only achieved their original objective of attracting paddle sports enthusiasts, but have often exceeded expectations by becoming focal points for their communities and recreational destinations for outdoor tourism. Whitewater parks often play host to major events centered on slalom or freestyle competitions or host river festivals that feature local arts and culture. In addition, Whitewater Parks can have a positive economic impact on the local community, as visitors spend money at local restaurants, lodging, and retail establishments. Some cities, like Golden, Colorado; and Reno, Nevada have reported impacts on the local economy, from tourism generated by the park, on the order of millions of dollars per year. The timing for the project is ideal. The Town has recently developed plans for riverfront revitalization, including construction a 3.5-mile greenway, and an additional 1.5-mile greenway, adding a new park, and developing funding for the revitalization effort. A bond referendum will go before Woodfin voters in November of 2016 to support funding. There are indications that additional funding may be available from public and private grants and other types of financial support. This study was commissioned by the Advocates for the Woodfin Whitewater Wave to determine the viability of creating recreational improvements in this reach of the French Broad. The objective of this study is to identify the feasibility of a potential whitewater park within the reach extending from the proposed Silverline Park to the Craggy Dam located along the downstream end of the old Woodfin Town Park.


Section 1: Whitewater Parks

Whitewater Parks Defined

Figure 1: The Hawea Surf Park is a natural-river type surf park, placed in the Hawea River, NZ

Whitewater Parks are river parks in which the whitewater has been designed in order to create a regional attraction1. In some cases whitewater parks are built in natural rivers and consist of natural rock “drop structures”. At higher flows these parks create waves, eddies, deflectors and other features conducive to recreational, instructional, and often competition-level kayaking as well as rafting. At lower flows these features are less powerful and allow for all-types of in-stream usage including tubing and other float traffic. The parks are designed to function in a number of ways providing streamside access for fishermen and other visitors to the park as well as viewing for spectators and spaces for the general public to gather and recreate on the banks as well as in the water. In other cases—cases where natural flow and gradient sufficient for whitewater do not exist—whitewater rapids are artificially created through the use of pumps and purpose-built channels. These systems recirculate water in the same manner that theme parks or fountains draw from a single source, and do not rely on the flows of nearby rivers and streams.

Figure 2 shows a Whitewater Park in use. These types of whitewater parks are typically designed to host all types of users from highly experienced competitors who come to these whitewater venues for Olympic-standard events to families and tourists who come to these venues to experience whitewater for the first time. The venues provide for commercial rafting wherein visitors are able to buy a rafting pass and take a guided raft trip down the channels, as well as recreational kayaking, floating, streamside seating and events.

1 Whitewater Parks, like many specialty fields, have a language all their own. Definitions for typical terms are shown in Appendix B


Figure 2: A pumped whitewater park features commercial rafting as well as a number of other active outdoor activities.

Both in-stream and pumped whitewater parks can become significant regional attractions that draw people not just from surrounding states, but from throughout the country and world. Often the visitors are drawn not just for the whitewater, but for the events that are hosted at these parks. Designing whitewater parks to accomplish all of these objectives is a process. Often the process is iterative and includes opportunities for local stakeholders to comment and update the designs. The following section details this process.

The Whitewater Design Process

Figure 3: Whitewater Parks are designed for many differing kinds of users.

Whitewater Parks typically require several stages of design. These stages include:

a) Feasibility/Conceptual Design—this is the first must-do part of a project. This phase is tasked with determining whether a particular project is possible and, if so, how it could look and function and what the approximate costs of the project would be. If done right this part of the project is very powerful as it provides the client with the materials necessary to pursue funding


and grants. Deliverables include a report and design documents such as a conceptual design and cost estimate, tasks required to complete a project, and permit requirements.

b) Flood Modeling—There is no existing and usable model of record for this reach of the river. Creating an effective existing conditions model will allow S2o to put specific dimensions to the concepts and to further refine probable costs for the project. This phase of design will require some surveying as well as some computer modeling using HEC-RAS software. This phase can be done separately, or as the first step of Preliminary Design.

c) Preliminary Design—this phase gets to the heart of the design elements of project. If the Feasibility phase is about identifying what needs to be done to complete a project, Preliminary Design is about doing them. It is a phase tasked with completing the necessary actions required to finalize the design functionality and layout and to gather and process the data necessary to undertake detailed design. Preliminary Design often includes all of the tasks related to preparing for permitting, surveying, creating baseline models, meeting with stakeholders and agencies to define constraints and objectives, and completing design documents to the permitting level.

d) Permitting—permitting is a process that permeates most of the design phases. It is typical to work with regulatory authorities during the preliminary design phase to establish criteria and priorities for the project. Permit applications are typically submitted following the completion of Preliminary Design. Some permits, as outlined below, have lengthy review times for specialty projects such as Whitewater Parks.

e) Detailed Design—the detailed design is about getting to the nuts-and-bolts of the project. Now that the project has been defined and adapted to the constraints and objectives laid out in Preliminary design the project is ready for detailed calculations and modeling. Often the level of computations and modeling is defined by the nature of the project. In some cases, such as the Holme-Pierrepont Whitewater Park, the project can be accomplished with 1-dimensional modeling. In other cases, such as the Calgary Whitewater Park, detailed physical models were undertaken.

f) Construction Documentation—this is the “after-design” phase. Documents are created that help define the project for the contractor including all sections, details, specifications and bid items. Often the whitewater park designer will work with the client or the community to step through these processes.

g) Project Bidding and Construction—the project is put to bid by the project owner and a contractor is selected and contracted.

h) Construction Oversight and Inspection—this is the dirty work. In this phase the contractor and the design team work together to build the project to our exacting specifications. Often we have representatives in the field virtually full-time to ensure an accurate build that is aesthetically beautifully and highly functional!

i) Course Commissioning—the final phase and the one where we finally get to get wet! Paddling experts get in the water and test the project, often tuning wave characteristics and project features until the project is fully functional and meets design objectives.


The process of design is informed by the input given from local stakeholders and regulatory agencies and is typically based on a standard of care that is evolving for this new industry. The following section details the many design factors which impact a project.

Design Factors for Whitewater Facilities:

Figure 4: A before and after view of the Hawea Whitewater Park

Figure 4, above, shows the improvements made to the Hawea Whitewater Park. This park, much like the proposed French Broad Whitewater Park(s) was created in a relatively low slope river. Design can be a challenge in some river environments due to the many factors that make up a river’s morphology. Whitewater Parks are a new phenomenon and typical design standards are just beginning to be created. There are some standards and guidelines which lend guidance to the design of in-stream whitewater parks that often define the character of whitewater parks in a given reach. The most comprehensive set of standards defined for Whitewater Parks was set by the Colorado Board of Professional Engineers. The Board found that the following tasks should be standard for whitewater park design:

a) Plans specifications and calculations should contain the following information: - Existing and proposed topography - Exact dimensions and proposed elevations/distances for any of the improvements - Methods of water control and erosion control during construction, or any type of

construction phasing.

b) Calculations should contain the following: - Structure calculations - Stability analysis - Seepage analysis - Backwater calculations - Analysis of sequent depths and hydraulic jump movement tendencies for smaller or larger

flows - Calculations for smaller or larger flows other than the design flows.

c) Technical Specifications should include the following


- Stability analysis - Backfill - Water control - Erosion control - Un-grouted rock/rip-rap or landscaping

Stability The structures which are built in the riverbed need to be stable and robust and need to be anchored in such a way that they are not moved by flows up to the 100-year flood event. Typical design guidelines for these types of drop structures are found in the Denver Urban Drainage Handbook (Urban Drainage Criteria Manual, 2013).

Experience shows that the structures tend to fail from scour/erosion and piping. These failure modes are a function of the soils upon which the structure is built with bedrock, for example, being the most stable foundation for a structure, and clay or sandy soils being the most problematic. In order to determine stability a geotechnical analysis is typically conducted and a scour and piping analysis are undertaken as a part of the design process.

Guidelines for the stability of drop structures can be found in the Urban Drainage and Flood Control District Handbook called the Urban Storm Drainage Criteria Manual (Urban Drainage Criteria Manual, 2013).

Costs There are many factors that could affect the cost of a particular Whitewater Park. These factors include physical constraints, such as the nature of the soils or the width of the river. Structures built on unstable soils, if feasible, require extensive construction in order to construct a stable platform for the drop structure. In some cases this includes expensive requirements such as sheet-pile cut-off walls.

Width of the river can also affect costs. Typical drop structures are founded on arched structures anchored into the bed and banks of the river. Arches are typically exponentially more expensive with width. An efficient drop structure is typically located in a narrow part of the river such that project costs are not prohibitively high.

The scope of the project can also affect costs. Some projects, such as whitewater parks at the base of dams, are necessarily large in scope and require multiple structures. Other projects are created in locations ideally suited to smaller scale improvements. In some cases a phased approach is recommended such that manageable portions of the project are completed per phase.

Location of the park in relation to sensitive ecosystems can also be a factor. Parks that are planned in critical habitat are more difficult to design and permit and often require extensive review periods and costly redesign. Selection of a site that is already impacted and that could benefit from the inclusion of a whitewater park to provide, for example, fish passage, can have the opposite affect and make permitting and approvals easier to attain.


Typical Economic Impacts of Whitewater Parks Whitewater Parks that have been built in similar Towns and Cities in the United States have become significant attractions. They bring enthusiasts and spectators alike to the residing communities, and have significant economic impacts through increased property values, direct spending at the site, tourism dollars, and dollars spent at local restaurants, shops and businesses. A whitewater park like the one proposed in Asheville can attract tourists and have an economic impact that is measured in the hundreds of thousands of dollars per year. In-stream whitewater parks located in Colorado have had impacts as high as $7-9 million dollars per year. Table 1 illustrates some typical economic impacts of these parks: Table 1: Economic Impacts of Whitewater Parks (per year in US Dollars) (Multiple sources)

The impacts of these parks are manifold and are based on regular usage at the Whitewater Park, as well as instructional programs, competitions, festivals, and other attractive events. Freestyle events that occur in Colorado every year can bring millions of dollars into the local economy on a single weekend alone. For example, the TEVA games in Vail, CO have a documented yearly economic impact of $3.5 million dollars. In addition to creating economic impacts, these events also help to market a particular community as an outdoor town and whitewater destination.

Section 2: Site Information

Woodfin and Asheville, NC Woodfin is a town of approximately 6,000 people located along the French Broad to the north of the City of Asheville. The Town was formerly a manufacturing center with some remaining manufacturing and distribution facilities located along the French Broad. Many of the residents of Woodfin live in the Town and commute to jobs in Asheville or in the surrounding region.

Woodfin is located adjacent to Asheville, which is a city of approximately 83,000 people located in the mountains of Western North Carolina. The larger metropolitan area surrounding Asheville includes the cities of Hendersonville and Waynesville with a total population of over 400,000 people. Asheville is located at the confluence of the Swannanoa and French Broad Rivers in the Blue Ridge Mountains. It has many national rankings from a variety of sources including, “One of the Best Outside Towns” from Outside Magazine (Motsinger) as well as one of the top whitewater destination in the US (Kahn)

River Location User Days Additional SpendingTotal Impacts

(Millions)

Clear Creek Golden, CO 13,000-14,000$910,000-$1.1

Million$1.3-2.2 Million

Blue River Breckenridge, CO 1,200-2,300 $220,000-$460,000 $0.4-$1.1 MillionGore Creek Vail, CO 1000-2,300 $3.5 Million $3.5-$4 Million

Sacandaga River Saratoga/Warren County, NY 17,600-25,400 $1.8-$2.8 Million $2.3-$3.7 MillionCuyahoga River Kent, OH 10,000-40,000 $200,000-$800,000 $0.5-$1.7 Million

Yampa River Steamboat Springs, CO 75,700 $4.9 Million $7.2 Million

Economic Impacts of Whitewater Parks


.Asheville has many waterfalls, swimming holes, and rafting opportunities nearby and can be considered to be at the center of Appalachian whitewater with famous boating destinations such as the Nantahala Outdoor Center, the narrows of the Green, the Chattooga, and other popular destinations in the near region in addition to the French Broad.

There are a number of significant cities in the region that contribute to Asheville’s, and potentially Woodfin’s, growing tourist economy. The Asheville area is located approximately 125 miles from Charlotte, the largest City in North Carolina, and approximately 200 miles from both Atlanta, GA and Knoxville, TN. This park could potentially become a significant regional attraction, drawing visitors from neighboring states to the Town of Woodfin Figure 5 illustrates a 200 mile radius around the Town of Woodfin (Free Demographics).

Figure 5: There are a significant number of large Cities that contribute to Asheville’s tourist economy (Free Demographics).

The Study Reach: The study reach is a stretch of the French Broad River that follows a proposed (and currently being implemented) greenway that extends from Woodfin along the river towards Asheville. An earlier study looked at potential sites in the Arts District; however this study analyzes sites at the downstream end of the proposed greenway located in Woodfin. Figure 6 shows the location of potential sites in Woodfin. The study reach is located along the French Broad River between the proposed Silverline Park site and the Craggy Dam.


Figure 6: The project area with respect to Asheville's City limits and the River Arts District

Three potential sites were identified within the project reach. The three sites include the proposed Silverline Park Site, the Riverside Park Site, and the Craggy Dam which is located at the Metropolitan Sewage Treatment Plant Site Dam (MSTP). The site locations are shown below in Figure 7. Design for these sites was highly dependent upon the river’s morphology in this reach.


Figure 7: The proposed project areas are located in Woodfin immediately south of the Craggy Dam. The three sites included in this study are the Riverside Park Site, the Proposed Silverline Park Site and the Craggy Dam.

Channel Morphology From its headwaters, high in the Appalachian Mountains, the French Broad River cuts through gently sloping topography with relatively expansive floodplains along the river's southern reaches upstream of Asheville, NC. Here average bed slopes are as little as 3 feet per mile. Downstream of Asheville the river channel narrows and bed slopes increase to between 16 to 30 feet per mile as the river descends into a series of gorges as it approaches the Tennessee State line.

Similar to the New River, the French Broad cut through the Appalachians as they rose up around it. Here the mountains are primarily composed of metamorphic rock that was uplifted during relatively recent collisions between two continental crusts.

The French Broad River in this reach is moderately sized river that is characterized as generally broad (hence the name) and slow moving. The riverbed is largely bedrock with apparent outcroppings


throughout the reach. There has been significant development in the river corridor including several road bridges and road development along both sides of the river.

Within downtown Asheville, extending down to Woodfin, the French Broad flows through a combination of residential and commercial zones downstream of its confluence with the Swannanoa River. Here there is extensive infrastructure within the active channel and floodplain including residential and industrial developments, railroad lines and facilities, bridge crossings, roads, and utilities.

There are a significant number of structures within the floodplain including numerous aging industrial buildings and warehouses. Some of these buildings have been restored and currently function as commercial properties. Others are abandoned and decrepit and are in need of removal or redevelopment. Some of these structures, or aging and abandoned flood berms/fill areas in the project area reside in the active floodway and removal of these buildings/fill from the floodway will decrease flood risks to adjacent property and allow for the restoration of a green buffer between the Town and the French Broad.

Additionally, there is a significant dam at the downstream end of the project reach. By inspection, the dam is approximately 12’ high with a flat, even crest and creates an impoundment that is several hundred yards in length (The Old Woodfin Town Park is located along this impoundment). Reports from local kayakers suggest that the dam impoundment extends further upstream as the flows rise in the French Broad suggesting a rising backwater effect from the dam (Hunt, 2016).

Flow information: The French Broad in this reach sees significant average flows and can have large flood events. Figure 8 shows the mean monthly flow data for the French Broad River at Asheville according to the USGS Gauge 03451500. Flow rates are shown in Cubic Feet per Second (CFS):


Figure 8: Average Monthly Flows on the French Broad River at Woodfin (cfs)

Figure 8 shows flows that are significant throughout the year with peak flows that average almost 3,000 cfs in the spring and flows that average greater than 1500 cfs throughout the remainder of the year. These flows are higher, on average, than most whitewater parks in America and are sufficient to create attractive whitewater within a whitewater park that features sufficient drop.

Flooding within the French Broad river system typically occurs in the spring following seasonal rain or in the summer or fall during tropical storm events. The flood of record occurred on July 16th 1916, with an estimated magnitude of 110,000 cfs, whereas the mean annual flood event is calculated as 16,663 cfs. The most significant floods in recent history occurred on September 8th, 2004 with an associated magnitude of 43,100 cfs and flooding on May 6th 2013 with an associated magnitude of 23,200 cfs. Finding a low water period of time with a lesser risk of flood events will help to set the likely window of construction for this facility.

As can be seen, flood flows in this reach are significant and dangerous. The size of these floods is of concern to this project and significant flood modeling will be required to understand the impacts of the proposed structures within the floodplain. Table 2 shows the 2, 5, 10, 25, 50, 100 and 200 year return flood flows for the French Broad at the Asheville Gauge. Note that the regulatory 100 year flood discharge is 63,000 cfs at Pearson Bridge on the French Broad River (Flood Risk Information System, 2014). This calculation represents a higher level of recurrence analysis than used in the available data in Table 2:

0

500

1,000

1,500

2,000

2,500

3,000

3,500

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Flows In the French Broad River at Woodfin, NC. (cfs) USGS Gauge 03451500


Table 2: Flood Recurrence Intervals in the French Broad River (OSU, 2014)

Table 2 shows that significant flooding events occur on a regular basis. A histogram of historical flood levels in the French Broad River is shown in Figure 9.

Figure 9: Peak Stream flows on the French Broad River at Woodfin, NC

Figure 9 shows the peak flood each year for the period of record at the USGS gauge in Asheville. The figure describes a river in which historic flows in the reach regularly exceed 20,000 cfs with many near or around 40,000 cfs. The size of these floods within the French Broad River corridor suggests several project concerns. Woodfin is a part of the Federal Flood Insurance Program (FIS) which places several limitations on the proposed project. In order to understand the limitations it is important to understand how the FIS delineates the river corridor.

Floodplain—The Federal Emergency Management Agency, FEMA, regulates development within the 100 year floodplain of the river. The 100-year floodplain is defined as the area that has a 1 percent chance of being flooded in any given year. One of the purposes of the Flood Insurance Study is to determine the boundaries and elevation of the 100-year floodplain at each location along the area of study. The area inundated during the 100 year flood is defined as the 100 year floodplain. Development is limited in the 100 year floodplain.

Floodway—within the 100 year floodplain an FIS defines a sub-area known as the active floodway. The regulatory floodway is designated as the river and adjacent lands required to dissipate flows without increasing the base flood elevation by a certain height, typically 1 ft (Floodway). The floodway, also known as the conveyance zone, is the portion of the floodplain which the government preserves in order to ensure that the river actively conveys flood flows

Recurrence Interval (years) 2 5 10 25 50 100 200Flow Rate (cfs) 11,551.86 17,764.19 22,724.91 30,021.74 36,275.41 43,269.49 51,113.03


through the river corridor. Development within the active floodway is typically limited to changes that do not cause a rise to the 100 year flood elevation. Such a project can receive a “no rise” floodplain development certificate. This is a typical permit approval for whitewater parks. In some limited cases a rise within the active floodway can be allowed. This requires an extensive Letter of Map Revision (LOMAR) process with FEMA. One of the requirements of approval for a LOMAR is no negative flood impacts to insurable structures within the floodplain2.

Given the wide and flat nature of the French Broad in the study reach, creating a significant whitewater feature without causing a flood impact will be a challenge. The combination of this geometry with significant flood flows and a number of insurable structures located in the floodplain requires a project that artificially creates drop at a given location at average flows while not causing an impact to the 100-year flood elevation. This will be a design challenge that likely requires an innovative design approach.

Flood Modeling Within the Reach The existing flood models for the reach are antiquated and done in an earlier version of floodplain modeling software. These HEC-2 models are limited in accuracy and difficult to update. S2o recommends that an updated flood modeling exercise be undertaken and that this model be used to aid in the design of in-stream structures. This task would include creating an “existing conditions model” of an extended reach of the riverbed with accompanying bathymetric survey. Depending on the results of the study, it may also be advisable for the City to undertake a Letter of Map Revision Process with FEMA in order to adjust the regulatory floodplain to match the new and more accurate study.

The flood modeling task, which is shown in the cost estimates below as a separate task, could be undertaken prior to beginning preliminary design or as the first part of the preliminary design process. The costs for this task have been subdivided to provide the client flexibility in the timing and funding source of this task.

Project Sites A site visit was conducted by S2o representatives on 6th of July, 2016. S2o toured the river from Jean Webb Park downstream to the Craggy Dam. Three sites along the French Broad in the study reach were identified as possible locations for a Whitewater Park. This study builds on a previous study that also identified three sites located closer to Asheville’s Arts District.

Woodfin Riverside Park Site The preferred location to construct the proposed Woodfin Whitewater wave is in conjunction with the Woodfin Riverside Park. It has the most ideal hydraulic properties of the three potential sites, its location relative to the Craggy Dam means it likely will not cause a rise in water surface elevations, and it has much of the existing infrastructure required for a central park. As will be detailed in subsequent chapter, the combination of these factors lead it to be the least costly and most functional option of the four proposed alternatives.

2 A full description of required permits is shown below in the permitting section of this report.


Site Description

Figure 10: The Riverside Park Site is located along an impoundment created by the Metropolitan Water Treatment dam.

The Woodfin Riverside Park site is located along Riverside Drive just upstream of the Metropolitan Water Treatment Facility, and is the preferred location for the proposed Woodfin Whitewater Wave. The dam at this location causes an impoundment that creates still water along the river for the bulk of this reach. At the upstream end of the Riverside Park are the footings of a former railroad bridge that crossed the river. At this site there is adequate drop and flow to create a whitewater drop structure.

There are several advantages to this site including that there are existing parking, picnic facilities, restrooms and trail facilities at the site. This provides for the entire access and support infrastructure required for the proposed whitewater park. Some of the current infrastructure at this site can be seen in Figure 11:

Figure 11: The Riverside Park

This location, according to discussions with a local paddler (Hunt, 2016), is backwatered by the Craggy Dam. S2o is investigating the flood characteristics of this location, however if true, the backwater effect of the dam will likely make this site feasible in rock as opposed to the moveable dam structures utilized above and at other locations. In high flow events, water is likely backed up above the Craggy Dam, creating a still reservoir of higher WSE’s further upstream. Anecdotally, this backwater effect will ‘drown


out’ any whitewater structure installed at the Woodfin Riverside Park. This phenomenon will be investigated further in the modelling phase of the project, but it is anticipated that the result of this effect will be that any whitewater structure will not cause a rise to the 100 year floodplain, such that the dual U-structure is a feasible option for this project site.

Figure 12 shows the aerial image of the Riverside Park Site:

Figure 12: Aerial image of the Riverside Town Park Site including the railroad bridge abutments ( (Google, 2015) A

The aerial picture of the site shows that the dominant feature is the former train bridge footings. The site features riparian growth along both banks, although there are some low lying buildings on the western bank of the river upstream of the Old Leicester Rd Bridge.


Land Ownership

Figure 13: Land Ownership at the Riverside Park site. (Buncombe County, 2014)

Land Ownership at the site is relatively simple with the railroad right of way on river left and the two northernmost lots being owned by the Town of Woodfin. Construction easements are likely required for the river left side of the project and any work performed must not interfere with the running of the railway. Table 3 lists land ownership in the project area:

Table 3: Land Ownership at the Riverside Park Site (Buncombe County, 2014)

It is important to note that this study does not state that these lands will be acquired nor that this is the City’s current intention. The study merely states that, in order for construction to occur, ownership or easements are required at the project location.

Pinnum Owner973003288400000 Town of Woodfin973004411700000 Town of Woodfin


Flood Impacts

Figure 14: Flood Zoning Information for the Riverside Park site (FEMA, 2016)

FEMA mapping shows that there are insurable structures in the floodplain located upstream of the Old Leicester Rd Bridge. Per floodplain requirements the proposed whitewater structures can have no measurable impact to the 100 year flood elevations at these buildings.


Proposed Silverline Park Site Site Description

Figure 15: The Silverline Park will be located on an existing, and largely undeveloped, piece of land adjacent to the French Broad.

The Silverline Park Site is located on Town-owned land located just downstream of the Silver-Line Plastics manufacturing facility. The proposed park is undeveloped at this time with early concepts for the park designs slated for the coming year. The proposed Greenways project is funded in this location and will provide trails and park improvements in this reach. Figure 16 illustrates the layout of this site:

Figure 16: Aerial Image of the Silverline Park Site (Google, 2015)

The river in this reach is very broad and flat. S2o did not see any recognizable drop sufficient to support a whitewater structure at this site. However, S2o did see appreciable drop located just downstream of the park adjacent to Riverside Drive and located just downstream of the commercial business property for Garbage Disposal Services, Inc. The location of this business can be seen below in the section regarding property ownership in the reach. Figure 17 shows this riffle crest at low flows:


Figure 17: The proposed Silverline Park Site.

The amount of drop available at the Silverline Park site is minimal but can be compared to other whitewater parks around the world. A typical minimum amount of drop for whitewater parks is approximately 1.5 feet for the amount of flow present at the site. While a survey has not yet been completed at this site, a site inspection reveals that there is approximately 2-4 feet of drop in this reach. There may be enough gradient at this site to support more than one drop.

The site features significant bedrock and will require some excavation as well as construction. The drop is located in an area of the river that also features a bend in the river which can affect the hydraulics of a whitewater feature. The feature will need to be located and oriented in a way that minimizes inertial effects at the drop.

Land Ownership

Figure 18: Land Ownership surrounding the Silverline Park Site. (source: (Buncombe County, 2014)

Land Ownership at the site is simplified by few landowners. The entirety of the river left bank throughout the project area is owned by the Norfolk Southern Railroad. The river right side features land owned by the Town of Woodfin with Silverline Plastics, Inc, located upstream of the Silverline Park Site, and Garbage Disposal Services, Inc. located downstream of the new park site. The remainder of the right bank is NCDOT right of way, but for a small sliver of a lot owned by Dorothy Brock. A construction


and access easement will likely be required from Ms. Brock if in-stream structures are located downstream of the Garbage Disposal Services. The downstream portion of the river left bank is also owned by the Town of Woodfin. However, the area on river left from just downstream of the Haywood Bridge extending upstream throughout the reach of this site is owned by Progress Energy of the Carolinas and Carolina Power. (Buncombe County, 2014)

Table 4 shows land ownership at the project site:

Table 4: Land Ownership near Silverline Park Site (Buncombe County, 2014)


Flood Impacts For all Flood Insurance Rate Maps provided by FEMA Table 5 shows the naming convention used to delineate the varying flood risk areas.

Zone AE: Floodway Areas: The floodway is the channel of a stream plus any adjacent floodplain areas that must be kept free of encroachment so that the 1% annual chance flood can be carried without substantial increases in flood heights.

Shaded Zone X: Other Flood Areas: Areas of 0.2% annual chance flood; areas of 1% annual chance flood with average depths of less than 1 foot or with drainage areas less than 1 square mile; and areas protected by levees from 1% annual chance flood.

Unshaded Zone X: Other Areas: Areas determined to be outside the 0.2% annual chance floodplain.

Table 5: FEMA FIRM Naming Convention for Flood Risk Areas

FEMA Zone Percent Chance Name Convention AE 1 % Annual Chance Flood Hazard Floodplain X 0.2 % Annual Chance Flood Hazard 500 year Flood Event

Figure 19 shows the flood insurance mapping for the Silverline Park Site:

Pinnum Owner973042045600000 Doster & Dorothy Brock973042617500000 Garbage Disposal Services, Inc.973051299800000 Town of Woodfin973052411300000 American Eagle Investments973061233700000 Silver Line Plastics


Figure 19: Flood Zoning Information for Silverline Park Site. (Buncombe County, 2014)

The flood hazard area shown in Figure 19 is significant to this project. Figure 19 features three flood delineations. Of significance is the fact that the whitewater park, which will be located in the active floodway, is situated in a reach in which there are a significant number of insurable structures. Figure 19 shows that the floodplain extends to Riverside Street and includes all of the aforementioned adjacent property owners. Recall that it is a requirement for construction that the proposed park does not cause an impact (a measurable rise) to any insurable structures in the project area.

Additional Considerations Historic Structures The National register of Historic Places lists several locations that are registered as historic places in Buncombe County (Wikipedia, 2014). However, none of these historic structures are near the project site.

Endangered Species A list of all endangered species in the region according to the U.S. Fish and Wildlife Service is shown in Table 6. The species highlighted in red are those that are either threatened (T) or endangered (E). All others are listed as Federal Species of Concern (FSC), and are not defined in the federal Endangered Species Act. This category is defined in North Carolina, by the Asheville and Raleigh Field Offices of the US Fish and Wildlife Service (Service) “as those species that appear to be in decline or otherwise in need of conservation and are under consideration for listing or for which there is insufficient information to support listing at this time. Subsumed under the term "FSC" are all species petitioned by outside parties and other selected focal species identified in Service strategic plans, State Wildlife Action Plans, or Natural Heritage Program Lists” (Endangered Species, Threatened Species, Federal Species of Concern and Candidate Species, Buncombe County, NC, 2014).


Table 6: List of Endangered Species for Buncombe County.

The project will need to consult with Fish and Wildlife to ensure that there is not habitat for species of concern in the project area. If there is habitat for concern, the project will need to work with Fish and Wildlife to determine if the project, in design or implementation, can minimize impacts in an acceptable manner.

Common Name Scientific name Federal StatusVertebrate:Allegheny woodrat Neotoma magister FSCBog turtle Clemmys muhlenbergii T (S/A)Carolina northern flying squirrel Glaucomys sabrinus coloratus ECerulean warbler Dendroica cerulea FSCEastern small-footed bat Myotis leibii FSCGray bat Myotis grisescens EHellbender Cryptobranchus alleganiensis FSCMountain blotched chub Erimystax insignis eristigma FSCNorthern long-eared bat Myotis septentrionalis PNorthern saw-whet owl (Southern Appalachian population) Aegolius acadicus pop. 1 FSCPygmy salamander Desmognathus wrighti FSCRed crossbill (Southern Appalachian) Loxia curvirostra FSCSouthern Appalachian eastern woodrat Neotoma floridana haematoreia FSCSouthern water shrew Sorex palustris punctulatus FSCYellow-bellied sapsucker (Southern Appalachian population) Sphyrapicus varius appalachiensis FSCInvertebrate:Diana fritillary (butterfly) Speyeria diana FSCFrench Broad crayfish Cambarus reburrus FSCSpruce-fir moss spider Microhexura montivaga EVascular Plant:Blue Ridge Ragwort Packera millefolium FSCCain's reedgrass Calamagrostis cainii FSCDarlington's spurge Euphorbia purpurea FSCFraser fir Abies fraseri FSCFrench Broad heartleaf Hexastylis rhombiformis FSCGray's lily Lilium grayi FSCGray's saxifrage Saxifraga caroliniana FSCMountain catchfly Silene ovata FSCMountain heartleaf Hexastylis contracta FSCPiratebush Buckleya distichophylla FSCSpreading avens Geum radiatum ESweet pinesap Monotropsis odorata FSCNonvascular Plant:Lichen:Rock gnome lichen Gymnoderma lineare E


Section 3: Proposed Improvements

Project Objectives

Figure 20: Spectators watching the Animas River Days event.

The project has multiple objectives. The primary objective with which S2o was originally tasked is to create an in-stream Whitewater Park in Woodfin to create outdoor branding and positive economic impacts to the region while creating a recreational amenity that could be used by many types of boaters.

The design of these whitewater features will need to meet the current regulatory requirements for work within waters of the United States. In so doing, it will need to show no net negative impact to the regulatory floodplain and will need to be of a design and construction method that is foreseen to allow for permitting under the Federal Clean Water Act. Additionally, the designs should be designed to allow for the restoration of in-stream and riparian habitat as well as the migration of fish upstream through the site. In Woodfin, where digital flood models of a current standard do not exist, this is problematic in the conceptual stages. A flood model must be created in order to better understand the impacts of this project or a design must be created that can reasonably expected to have no impact to 100-year flood elevations in any scenario. This is the design approach taken by S2o in this instance.

The park, or parks, depending on which locations are chosen for construction, will create recreational whitewater through drop structures that are designed to allow for surfing and river running as well as to create eddies, chutes, wave trains, and fish habitat that will be attractive to whitewater boaters, tubers, fishermen and other recreational users of the river.

Though shown in concept only in these drawings, the final design should include parking and access improvements to allow for the general public as well as boating enthusiasts to responsibly access and utilize the site. These access points should include areas for access and egress to the river via designed and maintained pathways and should contemplate use by a wide range of visitors including tubers and other “float through” traffic. All access and recreational areas are restricted to in-stream and the river right side of the river, with no accessible areas on river left so as not to intrude on the railway’s right of way. The two primary proposed designs are shown below, with additional designs for potential long term plans listed in Appendix A.


The Woodfin Riverside Park Site This is the preferred location for the Woodfin Whitewater Wave. The hydraulic conditions by way of gradient and flow are the most suitable for a whitewater feature, its location relative to the Craggy Dam indicates that any in-stream structure will have minimal negative impact on the floodplain, and it has much of the required park infrastructure already in place. Ideally, the existing park infrastructure of a trail network, picnic tables and other amenities could be enhanced in this project, with the whitewater structure becoming a focal point of the area to provide viewing opportunities and a place for events and community gatherings.

Conceptual Design The preferred conceptual design for the Woodfin Whitewater Wave is a single spanning U-structure located at the Riverside Park Site. The structure will be located adjacent to existing park amenities, including restrooms and enhanced pathways, with terracing rock lining the banks for comfortable spectating areas. Beach areas will be encouraged above and below the Wave, to provide both a welcoming area to spectate or relax, as well as an open river access point to both put in and take out of the river. The conceptual design is shown in Figure 21 and again in detail in Figure 22.

Figure 21: Layout for Riverside Park Site.


Figure 22: Detailed view of the proposed structure at the Riverside Park site

A single spanning structure has numerous advantages. A single structure capitalizes on the entire flow of the river, leading to a more attractive whitewater feature for river goers, creating a larger pool on the downstream end of the structure which provides an area of still water for enhanced safety and recovery while similarly benefit from the backwater effect of the Craggy Reservoir during large flood events. Local river users in the Woodfin and Asheville region have expressed this as their preferred option, and are anticipated to gain substantial utility from the proposed development.

It is likely that a rock structure could be created at the Riverside Park and that a pneumatically adjustable gate would not be required3. The type of drop that S2o recommends for this feature is called a “U-Structure”. U-Structures are versatile structures that can be designed to provide a basic hydraulic feature at lower flows that then grows in size and power as the flows in the river increase. The proposed structure, as shown above, would be a full width U-Structure that feature high, medium, and low flow channels as well as an overflow area for high volume flooding events. The size of each of these channels would be scaled based on historic flows in the river to provide the maximum benefit a common flow rates.

The structure would be built out of native rock from the area and would be anchored into the bed and banks of the river. While the structure would not be tunable using pneumatic structures, some amount of tuning could be done as follow up construction in subsequent years. This tuning would allow the wave to evolve into its final configuration, if needed. These structures are modelled in great detail to 3 While it is likely, S2o is unsure of the viability of a rock structure at this site. As such, Appendix A includes an adjustable feature for this site with accompanying cost estimate.


provide an accurate depiction of how the full scale structure will interact with the full range of expected flow conditions. Though these designs are typically installed on lower volume rivers with a significantly shorter bankfull width, such as the Arkansas River through Buena Vista and Salida in Colorado, there are examples of these same structures being used with great success such as in Glenwood Springs in Colorado.

This design is pending the full hydraulic investigation into the backwater effect of craggy dam, but it is expected that the backwater effect will fill in over the proposed whitewater structure in high flow events, such that the structure will not cause a rise in the 100 year flood elevations. As a result, the non-adjustable rock structures are listed as the first preference for their cost efficiency. Though, a separate design for this site is shown in Appendix A featuring adjustable head gates to pass flood waters should the hydraulic study show the rock structures as unfeasible.


Design Functionality This U-Structure is used to create a river wide "drop" and can be used to constrict lower flows to increase the velocity and power of the water. By adjusting the gradient of the flow over the U-drop a wave or hydraulic can be formed. The structure also features elevated wings that are positioned along both riverbanks. These wings provide an eddy for easy recirculation to the wave. This structure is also beneficial to the in-stream habitat. The gradient of the drop keeps a pool below the structure scoured and creates a natural habitat for fish and aquatic life.

Figure 23: Typical plan view of a U-structure

This structure is very stable and will accommodate high volume/high velocity flows. The structure features an arched shape laid in the plane defined by the riverbed with its footing sunk into the riverbank to bear these loads.

The structure is a tiered with a series of steps across its span to allow for use at a variety of water levels. The low flow channel can be designed to provide deep passage and a usable hydraulic feature during typical low flows. During the mid-range flows the low flow channel and part of the high flow would be submerged. During run-off the high flow channel would create a larger, more usable hydraulic feature (a hydraulic jump or wave train), and at extreme flood the river will overflow the shoulders of the


structure. The downstream side of these shoulders are stepped to provide seating during normal flows and to prevent the formation of dangerous hydraulics during extreme flooding.

At low flows the U-Structure will make a beginner/intermediate feature that is consistent and that provides for a beginner/intermediate experience that includes side surfing, surfing, spins and other basic maneuvers. More experienced paddlers will come at these levels and take part in surfing as well. Depending on the depth of flow at these lower flows, these more experienced paddlers will be able to attempt more advanced maneuvers such as cartwheels, loops, and other dynamic tricks in addition to basic surfing. As flows increase so too will the power of the wave feature. At higher flows the feature will become an attraction that draws boaters from the surrounding region. At these flows the wave feature will grow in power, height, and width. Paddlers will seek out the wave to pursue expert/advanced kayaking on a large whitewater feature that will be characterized as a wave/hole. The feature will provide for surfing, advanced freestyle, basic river crosses and navigation (below the main feature), as well as eddy service on both sides of the flow. Some typical whitewater park images for this type of feature are shown below.

Figure 24: A typical U-Structure created by S2o.


Figure 25: The U-Structure is used by many different types of watercraft.

Figure 26. The U-Structure wave will grow in power and width as the flows increase


Opinion of Probable Costs The expected cost of construction for this structure is shown in Table 7.

Table 7: Opinion of Probable Cost of Riverside Park Site.

Estimated Construction Costs of Riverside Park Site

Description Quantity Unit Unit Cost Item Total CostSite SetupTraffic Control 1.0 LS 5,000.00$ 5,000.00$

Install & Maintain Best Management Practices 1.0 LS 5,000.00$ 5,000.00$

Operate & Maintain Water Control 2.0 LS 75,000.00$ 150,000.00$

Whitewater U-Structure Install Equipment Access Ramps & Roads 2.0 EA 1,500.00$ 3,000.00$

Reclaim Equipment Access Ramps, Roads, & Staging Areas 2.0 EA 2,500.00$ 5,000.00$

Bedrock Removal 555.0 CY 350.00$ 194,250.00$

Excavate & Grade Native Alluvium 185 CY 22.00$ 4,070.00$

Furnish & Install Bedding Material 300.0 Tons 30.00$ 9,000.00$

Furnish & Install Mirafi 180n Filter Fabric 694.4 SY 8.00$ 5,555.56$

Furnish & Install Boulder (Avg 36" B Axis) 1853.7 Tons 85.00$ 157,564.50$

Riprap Pool Amoring 925.9 CY 75.00$ 69,444.44$

Furnish & Install Concrete Grout, Including Rebar, & Marine Epoxy 166.5 CY 272.00$ 45,288.00$

Unclassified Hauloff 740 CY 20.00$ 14,800.00$

Terracing, Steps and Circulation PathFurnish & Install Boulder (Avg 36" B Axis) 1390.3 Tons 85.00$ 118,173.38$

Excavate & Grade Native Alluviam 555 CY 50.00$ 27,750.00$



Furnish & Install crusher fines Walkways 6100 SF 0.30$ 1,830.00$


Additional Included ItemsPhysical Model 1 LS 120,000.00$ 120,000.00$

Additional Excavator Time as directed by S2o 80 HR 220.00$ 17,600.00$

PROJECT SUBTOTAL 986,259.21$

Contingency (25%) 246,564.80$

CONSTRUCTION SUBTOTAL 1,232,824.01$

Bathymetric/Topographic Survey 12,328.24$

Engineering Design 73,969.44$

Hydraulic Modeling 12,328.24$

Permitting 404, 401 24,656.48$

Permitting Floodplain 24,656.48$

Construction Bonding/Ins 36,984.72$

Mob and Demob 36,984.72$

Construction Stakeout 6,164.12$

Construction Monitoring 98,625.92$

TOTAL PROJECT COST OPINION 1,559,522.37$

Project: Asheville Whitewater Park Opinion of Probable Cost

Issue Date: 9/15/2016Developed By: JR


Proposed Silverline Park Site Conceptual Design In addition to the Riverside Park Site, a location of a Proposed Silverline Park was also investigated. The layout of this design is shown in Figure 27 while the structure is shown in detail in Figure 28.

Figure 27: Proposed layout at the Silverline Park Site


Figure 28: Rendering of the Whitewater Park at the Bowen Bridges Site.

In this design, a fixed U-structure is shown alongside the re-configurable Obermeyer gate option. The U-structure features the same design benefits detailed in the primary Riverside Park design. As this project site is further upstream from the Craggy Dam, and out of the expected range of the backwater effect, further design efforts were made to accommodate the 100 year flood without causing a rise in the known water surface elevations. This design features an adjustable Obermeyer Dam which can be raised to provide the necessary head difference over the structure to create a whitewater feature, but the gates can be designed to lower automatically in the event of high flow, preventing any negative impact on the water surface elevations. Additionally, higher quality whitewater features can be configured using the adjustable RapidBloc™ system.


Design Functionality

Figure 29: Each of the designs utilizes a layout that constricts the river using Obermeyer Gates into a main wave forming chute.

The pneumatic design would consist of a main wave feature in the central portion of the structure. In the conceptual design of this project the main feature would be a RapidBlocs™ compatible feature in which the wave could be adjusted and configured to an optimum shape. This would allow for a dynamic feature that was tuned during low-flow events and that was than adaptable to evolve as the sport evolves.

Figure 30: The wave forming chute utilizes RapidBlocs(tm) to create a reconfigurable wave.

The remainder of the overflow portion of the river would be an articulating dam feature known as an Obermeyer Gate. These types of pneumatically adjustable gates can be raised and lowered and can be further configured to deflate automatically during large flooding events. During low and normal flows


the articulating gates could be used to raise the water surface elevation by 1’-2’ thereby creating drop over the main wave feature that does not exist in the current configuration. Lowering of the gates would also allow for fish passage, flood conveyance, or the passage of other watercraft either through two chutes (water allowing) or during times when surfing is not occurring at the venue. The amount of articulating structure that is required will be designed during the detailed design phases and can be minimized to save on project costs. The remainder will be faced in natural rock from the region in order to create an environmentally friendly and aesthetically pleasing structure.

Figure 31: The Obermeyer gates are articulated pneumatically using an airbag that lifts the main plate of the structure.

One of the key technologies that make this design approach viable is the use of the Obermeyer-type gate. This gate, shown in Figure 32, allows the river to be modulated but then, at higher flood flows, collapses and has no impact on flood water surface elevations.


Figure 32: The Obermeyer gates are actuated pneumatically. S2o proposes to use a more natural appearing version of this gate.

The gates would provide many functions. By utilizing the versatility provided by the actuators:

x Certain gates could be open for providing a bypass to the wave for the existing tubing. x Certain gates could be opened for maintenance at the site x Certain gates could be actuated to allow for fish passage. x All of the gates could be collapsed to provide for capacity during a flood event or to create a flat

water site in the event of a safety issue. x Certain gates could be actuated for adjusting the character of the wave.

While Figure 32 shows a large amount of concrete and mechanical items, S2o proposes a design that would be more natural appearing and that would be further camouflaged by excess water flowing over the gates. Additionally, while the gates are currently shown as a river-wide implementation in the concept drawings, detailed design would allow S2o to minimize the amount of Obermeyer gate used, thereby minimizing costs as well as improving the overall aesthetics.

This design for the project significantly contributes to the safety of the park. The expert feature can be configured in the main flow while beginner bypasses can be configured on the side of the river.


The role of the novice channel is important to this design. The novice channel will operate in parallel with the main feature and will provide for the existing usage in the river including tubing, rafting, and inexperienced hard boaters. This novice channel will provide a class I-II option that can be easily navigated.

Additionally, differing gates can be actuated in the event there is an issue in order to aid in the rescue effort. This type of design is ideal for accommodating existing users, such as tubers and rafters, while allowing for expert level boaters to use a more advanced feature. The design of both the main feature and the novice channel will include roughened bed elements along the banks to provide for fish passage. Design of these features will be done in cooperation with local governmental authorities to ensure compatibility with native species.


Costs of Construction: The opinion of probable cost of this option is shown in Table 8.

Table 8: Opinion of Probable Cost

Estimated Cost of Construction of Silverline Park Site




Adjustable Whitewater StructureInstall Equipment Access Ramps & Roads 2.0 EA 1,500.00$ 3,000.00$


Furnish & Install Rapidblocks 1.0 LS 75,000.00$ 75,000.00$

Furnish & Install Unistrut Rails 930 LF 3.05$ 2,836.50$

Furnish & Install Pneumatic Gates 94 LF 4,000.00$ 376,000.00$

Bedrock Removal 300 CY 350.00$ 105,000.00$


Furnish, Install, & Finish Concrete Ramp (CDOT Class D) 154 CY 300.00$ 46,311.11$

Furnish & Install #5 Rebar 5820 LF 2.00$ 11,640.00$


Riprap Pool Armoring 85 CY 75.00$ 6,388.89$

Fixed Whitewater StructureInstall Equipment Access Ramps & Roads 2.0 EA 1,500.00$ 3,000.00$
















Additional Included ItemsAdditional Excavator Time as directed by S2o 80 HR 220.00$ 17,600.00$

Physical Modelling 1 LS 120,000.00$ 120,000.00$

PROJECT SUBTOTAL 1,271,634.36$

Contingency (25%) 317,908.59$





Permitting 404, 401 31,790.86$










Physical Modelling Physical modeling is recommended for the sites detailed in earlier sections. Given the amount of investment into a single structure S2o recommends that the physical model be undertaken in order to ensure the maximum utility and of the proposed project. Permitting can occur in parallel with the Physical Model Study. Following permitting S2o recommends completing detailed design and construction documents.

Section 4: Process and Permitting

Process This study has evaluated three sites and suggested one possible design solution for each that would meet the site constraints and requirements and that would provide a recreational attraction. This is not, however, a completed design that is ready to be constructed. Typically our design process would incorporate Preliminary Design, Detailed Design and Construction Documents design phases. Following the preliminary phase permits would be submitted and would need to be attained. This may require some design adjustment. It is also suggested, given the lack of available information and extensive flood risks in the corridor, that the City also undertake a floodplain modeling exercise which would include some regulatory process with FEMA as well. The design and permitting phases of a project of this type are typically approximately 2 years but can be accelerated if required. Once construction documents have been completed and the permits have been attained the project will need to be constructed. Typical construction times for a project of this size would be approximately 4 months. Construction typically takes place during the months when the flows are lower and when there is less impact to in-stream species. Construction windows are often set by permitting authorities.

The project will require Federal, State, and Local permits in order to be completed. At a minimum the project will require:

Federal and State Permitting: U.S. Army Corps of Engineers (USACE)

Clean Water Act, 404/401 Permits (Joint Application): Although there are numerous federal and state laws that affect wetlands, the Clean Water Act (CWA) is the main regulatory tool. There are two sections of the CWA that are of particular significance:

Section 404 of the Clean Water Act enables the USACE to grant permits for certain activities within waterways and wetlands. Construction projects affecting wetlands in any state cannot proceed until a §404 permit has been issued. In deciding whether to grant or deny a permit, the Corps must follow certain guidelines, which are discussed below. Section 401 of the Clean Water Act gives EPA the authority to prohibit an activity, including a construction project, if it can adversely impact water quality or have other unacceptable environmental


consequences. For most states, EPA has delegated this authority to state environmental agencies. In North Carolina, the Division of Water Resources (DWR) is the state agency responsible for issuing 401 water quality certifications (WQC). When the state issues a 401 certification (which is required for any federally permitted or licensed activity that may result in discharge to waters of the U.S.), this certifies that a given project will not degrade Waters of the State or violate State water quality standards. (North Caronlina Division of Environment and Natural Resources, 2014)

Whitewater Parks typically require an individual (404) permit which can be a lengthy review process that includes review of all impacts of the park to the environment including both in-stream and riparian zone as well as impacts to affected stakeholders. It would be typical that other departments, such as the Department of Environmental Conservation, fish and wildlife, and others would be consulted as a part of the process

Buncombe County: Buncombe County provides a complete checklist covering permitting and planning requirements for any development within county limits. To see the full checklist refer to Appendix B. While all steps must be completed on this checklist the main planning requirements include contacting Buncombe County Planning Department regarding both zoning requirements and flood zone information. The permitting requirements are also outlined in this document. The main items of importance to this project include:

x Stormwater Management Permit (If disturbing >1 acre of land) x Erosion Control Permit (If disturbing >1 acre of land) x Floodplain Development Permit x Building Permit

A number of tasks will be required in order to attain these permits including a detailed site survey with wetland delineation, a flood model to establish no-rise, and design drawings stamped by a licensed professional engineer. Other studies may be required in order to assess habitat, environmental, or other impacts.

Town of Woodfin: The Town would require a floodplain development permit (in some Towns the floodplain development authority is the County) that shows no flood impacts to other properties, and a grading permit. The contractor will typically also require a stormwater run-off permit prior to the onset of construction.

Construction Requirements Analysis: The construction of whitewater parks typically requires a detailed construction plan. Whitewater Parks normally require a large staging area for materials, access to and from the riverbed, and the ability to control the water through temporary berms or dams that will create a dry work area.


Figure 33: The Durango Whitewater Park was constructed in 2014 during a low water time period and using water control to maintain a dry work area per 404 and 401 permitting.

The type of construction shown in Figure 33 wherein water is diverted away from the work area is typical of in-stream construction of Whitewater Parks. Typically low flows are required for this type of work. In a river of the size of the French Broad water control can be a significant cost item.

Another typical concern for Whitewater Parks has to do with fish passage up and down the structure. S2o will work with regulatory agencies during the design phases of this project to ensure that the structures are passable by native fish species in the reach.

River access is also a concern. The contractor will require a staging area as well as vehicle access to the riverbed. Often this requires restoration of the bank areas as the construction project is completed.

Other Construction Issues: Endangered Species Act: Endangered Species in the area could limit construction access and construction timing. This will require consultation with the Fish and Wildlife service as outlined above.


Site Evaluation

Figure 34: An eleven-year old boater surfs the Hawea wave during competition.

In order to aid the City in evaluating the proposed sites and selecting a preferred solution or solutions, S2o has created a site-selection matrix which evaluates the proposed designs against the objectives and challenges of this project. This matrix is shown below:

Table 9: Site Selection Matrix

The matrix evaluates the sites against seven differing criteria. Based on the information available S2o recommends that the Riverside Park site be considered the preferred alternative. This site has ample opportunity for expanded park amenities, parking, and access. The acquisition of this site will allow for

Consideration Riverside Silverline Craggy Dam1 Parking and Access + 0 -2 Potential Flood Impacts + 0 +3 Relative Costs + 0 -4 Land Ownership + + -5 Recreational Opportunity + + +6 Economic Impacts + + +7 Accomodates or Enhances Existing uses + + +


further expansion of the Town’s greenways as well as opportunities for new business development. These acquisitions also allow for decreased impacts to the floodplain.

Conclusion

Figure 35: Spectators watching rafters surf the wave.

A whitewater park is proposed in the Town of Woodfin, NC on the French Broad River. Three sites were investigated and were found to be feasible. Of these three sites the preferred site is the Riverside Park. This site will meet project objectives and will have complementary benefits in terms of expanded parkland, parking and access, flood mitigation, and economic development. At this stage, it is expected to be able to meet the project objectives a grouted rock structure will be sufficient, but alternate designs with adjustable head gates have also been investigated.


Appendix A: Additional Alternative Designs

Riverside Park Dual U-Structure A dual spanning set of two U-Structures is also proposed for the Rivierside Park Site. While this design does not fully encompass the available flow and stream power into one single wave, the design allows for two separate waves to exist, which would be tuned to allow for recreation at a variety of flow rates. Similarly, one of the structures would be tuned to cater for more advanced river goers, with a more dynamic and powerful wave and the other structure could cater for more novice users. The conceptual layout of this design is shown in Figure 36 and again in detail in Figure 37.

Figure 36: Layout for Riverside Park Site with the dual U-structure


Figure 37: Detailed view of the proposed dual structure at the Riverside Park site

The associated costs with this design option are shown in Table 10.


Table 10: Opinion of Probable Cost for Dual U-Structure Design.

Estimated Construction Costs of Riverside Park Site




Fixed Whitewater U-Structure River LeftInstall Equipment Access Ramps & Roads 2.0 EA 1,500.00$ 3,000.00$










Fixed Whitewater U-Structure River RightInstall Equipment Access Ramps & Roads 2.0 EA 1,500.00$ 3,000.00$
















Additional Included ItemsPhysical Model 1 LS 120,000.00$ 120,000.00$

Additional Excavator Time as directed by S2o 80 HR 220.00$ 17,600.00$


Contingency (25%) 268,271.79$





Permitting 404, 401 26,827.18$










Riverside Park Articulating Structure A fully adjustable whitewater structure is also proposed at the site of the Riverside Park should the hydraulic modelling component of design deem the grouted rock structure unfeasible for flood passage. This structure would consist of two concrete slabs with reconfigurable obstacles with the collapsible Obermeyer dams between them. The conceptual layout is shown Figure 38 and again in detail in Figure 39.

Figure 38: Layout of Riverside Park with adjustable head gate option


Figure 39: Detailed drawing of adjustable whitewater structure.

Both the whitewater features in this design are fully adjustable to configure to a variety of flow rates and river user, while the Obermeyer dams allow for safe, unimpeded passage of the 100 year flood.

An opinion of probable cost is shown in Table 11.



Estimated Construction Cost for Riverside Park Articulating Feature




Adjustable Whitewater Structure RLInstall Equipment Access Ramps & Roads 2.0 EA 1,500.00$ 3,000.00$











Adjustable Whitewater Structure RRInstall Equipment Access Ramps & Roads 2.0 EA 1,500.00$ 3,000.00$


















Physical Model 1 LS 120,000.00$ 120,000.00$


Contingency (25%) 373,538.64$





Permitting 404, 401 37,353.86$










The Craggy Reservoir Dam Site (Metropolitan Sewer District Dam) Site Description

The Craggy Reservoir Dam Site, more commonly known as the Metropolitan Sewer District Dam) is perhaps the most challenging of the proposed sites, but also provides the most opportunity for improvements. Advocates have made it clear that this site might best be considered as potential project for the long-term future, and not the focus of any current initiative. The site features a dam of approximately 12 feet in height with continued slope in the riverbed downstream of the proposed project area. The site features more drop and therefore available power than any other location in the reach.

The site comes with challenges however. Figure 40 shows the site layout:

Figure 40: Aerial image of the Craggy Reservoir Dam Site (note: the northerly direction is to the right of this image). (Google, 2015)

In this image it can be seen that the current configuration of the river features a railroad track along the left bank and a hydro-canal along the right bank. The canal and associated hydro-generation and water


treatment works create a challenge to access and utilization. While solvable, solutions at this site will need to provide for access, egress, and areas from which to view the whitewater channel.

Land Ownership

Figure 41: The floodplain at the Craggy Dam Site (FEMA, 2016)

The image below shows the parcel numbers and land ownership information for the land surrounding the potential whitewater park.

The river left bank is again dominated by the railroad right-of-way. The river right bank is shown as being in the road right-of-way but by inspection it can be inferred that the hydro-generating facility has construction access and land-ownership or easements along the right bank. Consultation with both of these entities will be required prior to determining the full feasibility of this site. Table 12 provides land ownership information for the land surrounding the proposed project site.

Table 12: Land Ownership information for land surrounding the Craggy Reservoir Dam Site


Pinnum Owner973018274400000 Metro Sewage District973017688100000 Progress Energy of the Carolinas973017371000000 Metro Sewage District973007366600000 Craggy Land Co, Inc


Flood Impacts This reach is also extremely flood prone. The active floodway is contained within the riverbed in this reach but the floodplain is wide and flat. The 100 year floodplain features a central island there much of the development exists but there are insurable structures within the 100 year floodplain adjacent to the site. As with all of the sites identified along this reach, flood risks will be significant.

Figure 42: The floodplain at the Craggy Dam Site (FEMA, 2016)

Conceptual Design The conceptual design of the proposed whitewater park at the site of the Craggy Dam is shown in Figure 43.


Figure 43: Layout of the proposed whitewater park at the Craggy Reservoir.

The Craggy Reservoir Site is different than the Riverside Park and the Silverline Park in that an existing dam of approximately 12 feet in height is located at the site. The whitewater park proposed for this site would be a side-channel-type whitewater park that created an extended ramp of flow along the path of the existing hydro-channel located at the site. This channel could be designed to accommodate varying flow rates, and be of varying lengths (slopes) depending on priorities identified in the design stages.

The type of whitewater created in these types of channels is different than that seen at the U-drops shown above. In lieu of a single wave, a more extended reach of whitewater will be created similar to the type of whitewater that the Olympic Games are competed on. Figure 44, shown below, shows an image of how this kind of whitewater channel could look:


Figure 44: A purpose built whitewater channel with a moveable obstacle system

Typically these types of channels provide multiple benefits at a dam site. The primary benefit is that they create a hydraulic link between the river downstream of the dam and the pond upstream. This link allows for fish passage up the dam and connects the reach. Additionally, the same link allows boaters to navigate the dam without having to portage on either the water treatment plant side or the railroad tracks side of the river. The channels require less water (approximately 350-500 cubic feet per second) than in-stream whitewater parks and can be shut off for maintenance or to reconfigure the rapids. These types of channels are also used for a variety of different competitions/festivals including national and international-level events.

It is also versatile in terms of how the use of the park can be controlled for different users. If the hydro-plant needs the water, then the channel can be closed to push the full amount of flow into the hydro-channel for power generation. If the water is too high for boating then a set-amount can be allowed into the channel for a controlled experience at reasonable flows. The channel can be opened in full to help lower the effective flood level during flooding events. Figure 45, shown below, shows an image of another dam with a similar bypass channel:


Figure 45: A bypass-channel whitewater park in Prague, CZ

As seen from the construction drawings, a U-drop structure is also shown alongside the base of the channel. This is a further optional feature, with similar design characteristics to the whitewater structures detailed in earlier chapters, and can be installed in conjunction with the extended channel.


Opinion of Probable Cost The expected cost of construction for this structure is shown in Table 13.


Estimated Construction Costs of Craggy Dam Site




Whitewater ChannelInstall Equipment Access Ramps & Roads 1.0 EA 175,000.00$ 175,000.00$


Compacted Fill 6666.7 CY 35.00$ 233,333.33$

Furnish, Install, & Finish Concrete Channel 5920 CY 375.00$ 2,220,000.00$








Fixed Whitewater StructureInstall Equipment Access Ramps & Roads 2.0 EA 1,500.00$ 3,000.00$










Terracing, Steps and Circulation PathBridges 2 LS 125,000.00$ 250,000.00$





Furnish & Install crusher fines Walkways 2000 SF 0.30$ 600.00$



Physical Model 1 LS 120,000.00$ 120,000.00$


Contingency (25%) 1,265,697.07$





Permitting 404, 401 126,569.71$










Appendix B: Buncombe County Permitting Checklist


Appendix C – Preliminary Schedule and Associated Costs

Key Project Dates Phase Tasks Estimated Costs - Riverside Rock Structure

Estimated Costs - Silverline Adjustable Structure

Assess Community Interest

Assess funder Interest

Bond Referendum November 8th

Hydraulic Modelling - Existing Conditions $6,164.12 $7,947.71Bathymetric/Topographic Survey $12,328.24 $15,895.43Engineering Design - Prelim Design Assessment $14,793.89 $19,074.52

Engineering Design - Develop plans sufficient for Permitting and Development of Physical Model

$29,587.78 $38,149.03

Hydraulic Modelling - Proposed Conditions

$4,931.30 $6,358.17

Engineering Design - Update to Project Cost Estimates $3,698.47 $4,768.63

404, 401 Permitting - Submit to Regulatory Agencies for Permitting

$24,656.48 $31,790.86

Engineering Design - Make Necessary Adjustments to Preliminary Design $7,396.94 $9,537.26

Physical Modelling - Development of 1/14th Laboratory Scale Model

$120,000.00 $120,000.00

Engineering Design - Adjustments to Preliminary Design $14,793.89 $19,074.52

Engineering Design - Design and Construction Drawings Completed $3,698.47 $4,768.63Hydraulic Modelling - Final Hydraulics for No-Rise

$1,232.82 $1,589.54

Floodplain Permitting $24,656.48 $31,790.86Gather and Evaluate Contractor Bids

Finalization of Cost Estimates Based On Contractor Bids

Construction Materials $866,259.21 $1,151,634.36

Construction Bonding $36,984.72 $47,686.29

Mob and Demob $36,984.72 $47,686.29Construction Stakeout $6,164.12 $7,947.71

Construction Monitoring $98,625.92 $127,163.44

N/A Contingency25% Contingency - Construction Materials and Physical Modelling $246,564.80 $317,908.59

Sunday, September 01, 2019 CommissioningRibbon Cutting and Opening of Project for Public Use 0 0

0

0

$2,010,771.83

Contractor Mobilization and

Construction

Physical Model Development and Detailed Design

(90%)

Total Project Cost $1,559,522.37

November 2018 – January 2019

Design Submittal (100%)

January 2019 – April 2019

Construction Drawings, Bid, and

Contract for Construction

0

May 2019 – August 2019

August 2018 - November 2018

January 2017 - May, 2017 Preliminary Design Phase

June 2017 – August 2017Preliminary Design

(30%)

September 2016 – December 2016

Woodfin Leaders and Local Advocates Assess Project and Funding Potential

0

September 2017 - November 2018

Permitting Phase


Appendix D: Glossary

These terms are often used in the white water parks business. Let us know if you are left wondering about a term or phrase—we’ll add it to the list!

2-Dimensional Flow Models: Flow models such as River 2d show the nature and distribution of flows. Flow 2d models are often useful for establishing fish passage by adjusting the design to meet flow criteria established with permitting authorities.

3-Dimensional Flow Models: Flow models such as Fluent or Flow 3d that use computational fluid dynamics to compute virtually every characteristic of the flow including vortices, turbulence, water surface character, and more. These models are often less informative and more expensive than creating an actual physical model.

Business and Market Analysis: A study that establishes what the market potential for a whitewater park is in a given community including total expected visitorship and the character and demographics of these visitors. We also use research data to establish price point and complementary amenities. Based on this information we create a business and operations model for the client. Our models are very robust and have, without comment, been reviewed by independent as well as state and banking reviewers in preparation for grant and loan funding. Beware of freebie and cheap “general purpose” business models. These are the only white water park business models that provide operators and financiers the information that they need, for their project, to make it happen.

Class I-VI: Whitewater rapids can be classified according to difficulty and risk. A generally accepted classification system typically uses roman numerals between I and VI with I being the easiest to navigate and appropriate for beginners with obvious lines and very little power and class VI being the most difficult with steep and powerful lines that are difficult to attain and maintain even for the best expert boaters.

Dangerous “Keeper” Hydraulic: Hydraulic jumps vary in power and character. In general the gamut of hydraulic jump types varies from glassy green wave to a hydraulic jump that features dangerous recirculating currents that swimmers have difficulty existing. The designers challenge in whitewater park design is to create a whitewater feature that has sufficient power to be a play feature, but not so much power that it creates a hazard to beginner boaters.

Economic Impact Study: A study completed in cooperation with a PhD in economics. We study the economics of the region surrounding the park and establish, based on published data (or surveyed data if published data does not exist) what the economic impact of a whitewater park will be to a host community in terms of total dollars, increased tax revenue, increased average incomes, increased jobs, and other pertinent economic metrics.

EPDUK: S2o’s design partner in Great Britain. S2o and EPDUK partnered together on several projects including the London Olympic Park Project.


Floodplain Analysis: A process that undertaken to understand the effect of a whitewater park on a floodplain at a particular project site. Often the floodplain analysis is conducted hand-in-hand with the project design to minimize or eliminate flooding impacts.

Freestyle Feature: A surf or play feature of sufficient size and power to be used for Freestyle, or trick kayaking, competitions.

Freestyle kayaking: A type of whitewater competition in which paddlers surf in a wave or hydraulic and perform tricks over a set time period. The paddlers are scored according to style, difficulty, and number and variety of tricks. Large events such as the Teva Mountain Games, which are held in the Nick Turner (now of S2o) designed pneumatically adjustable play feature can have an economic impact of $3.5 million dollars in a single weekend event!

HEC-RAS Model: a one dimensional flow model developed by the Army Corps of Engineers to predict flood elevations in rivers. This software has limited applications to Whitewater Design—particularly within floodplains.

Kayak Park: A whitewater park designed specifically for kayaking. Many of the freestyle whitewater parks are custom designed to create waves and play-holes specifically for kayaking

Physical Model: A Froude scaled model that is hydraulically scaled (using the Froude number relationship) to mimic the behavior of a full-sized river. If done properly this model can accurately predict wave size, height, and shape as well as depths, velocities, and other pertinent course features.

Play Features: Similar to Surfing Features. Surfing features in whitewater parks are waves or hydraulic jumps which are conducive to surfing a kayak, stand-up-paddleboard (SUP) or surf board. These waves are called standing waves and remain stationary in the current (in comparison to waves in the ocean which transit a body of water and break on the beach).

Run-Of-The-River Type Features: Whitewater Park features which are a challenge or that augment the experience of running the river. These features contrast with Freestyle and Play features in that they provide a navigational challenge to varying levels of boater.

Slalom kayaking: A type of whitewater competition in which kayakers are timed going through a set course of slalom gates (poles hung from wires above the river/channel). Paddlers are timed and scored with the winner posting the fastest time. Large events, such as the 2008 Olympic Team Trials can have as many as 30,000 spectators in a single weekend and can have millions of dollars in economic impact to a hosting town or city.

Slalom Racing/Slalom Features: Whitewater Slalom Racing is a timed event wherein kayakers race through a set of 18-25 slalom gates hung in a whitewater rapid. Athletes are scored based on total running time plus assessed penalties for touching or missing the gates. Slalom Features are features that are conducive to setting challenging slalom courses.


Surfing Features: Similar to Play Features. Surfing features in whitewater parks are waves or hydraulic jumps which are conducive to surfing a kayak, stand-up-paddleboard (SUP) or surf board. These waves are called standing waves and remain stationary in the current (in comparison to waves in the ocean which transit a body of water and break on the beach).

Swift water Rescue Park: a park designed specifically to help train rescue authorities in swift water rescue. These parks can hold cars, trees, and platforms in the main flow and can be turned off in an instant if a rescue or scenario becomes dangerous.

White water Park Design: The planning, design, market and business analysis, and creation of construction documents for a white water park.

Whitewater Raft: a watercraft that is inflatable that is typically designed to carry paddlers through a whitewater rafting. Rafters can be commercial rafters as a part of a for-profit business, or private rafters, who own or acquire their own inflatable watercraft.

Width, Depth, And Aspect Ratio When Referring to Whitewater Features: Constructed whitewater features—in particular freestyle features—typically span the river or channel in which they were built. These features, in order to meet permit and FEMA requirements need to match existing river morphology in the reach. As a rule the existing bed therefore defines the width, depth, and aspect ratio of the existing river bed and the designer often checks, by inspection, that the selected location is appropriate for improvements given the existing aspect ratio of the river.


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