Appendix A-6 328-386 River Park Preliminary Engineering Report_01152024_Draft.pdf

PRELIMINARY ENGINEERING REPORT

FOR THE

CITY OF CUMBERLAND

ALLEGANY COUNTY, MARYLAND

RIVER PARK & NORTH BRANCH POTOMAC

INDUSTRIAL DAM REMOVAL

CEC PROJECT #328-386

JANUARY 2024

i

Recreation Engineering & Planning

PRELIMINARY ENGINEERING REPORT

FOR THE

CITY OF CUMBERLAND

ALLEGANY COUNTY, MARYLAND

RIVER PARK & NORTH BRANCH POTOMAC INDUSTRIAL DAM

REMOVAL

INDEX

1. INTRODUCTION 1

A. Project Background

B. Project Scope

2. SITE ANALYSIS 2

A. Existing Site Photographs

B. Site Opportunities & Constraints

C. Hydrology

D. Floodplain Feasibility Analysis

E. Dam Structural Analysis

F. Aquatic Species

G. Construction Feasibility

H. Sedimentation Analysis

I. Canal Water Intake Analysis

J. Combined Sewer Overflow (CSO) Outlet Structure

K. Upland Analysis

3. PRELIMINARY DESIGN IMPLEMENTATION 18

A. Whitewater Park Design

B. Upland Design

C. Water Intake Design Options

D. Sediment Dredging/Passive Release Design Options

E. CSO Outlet Structures

4. CONCLUSION & NEXT PHASES 23

5. COST ESTIMATE 27

6. APPENDIX 29

PRELIMINARY ENGINEERING REPORT

FOR THE

CITY OF CUMBERLAND

ALLEGANY COUNTY, MARYLAND

RIVER PARK & NORTH BRANCH POTOMAC INDUSTRIAL DAM

REMOVAL

1. INTRODUCTION

A. Project Background

The River Park at Canal Place embodies a long-held vision for transforming Cumberland and Allegany County into a hub for outdoor enthusiasts. This initiative aims to unlock the recreational potential of the Potomac River, drawing inspiration from the success of

Cumberland's Great Allegheny Passage and the C&O Canal Towpath Trail (Towpath).

At its core, the project seeks to create a family-friendly whitewater park, converting the previously perceived obstacle of what is known locally as the “Blue Bridge Dam” into an opportunity. The removal of part of the dam allows for innovative whitewater features catering to various skill levels and to promote fish passage upstream of the dam for the first time since its construction in the 1950s. Complementing the in-water features are streamside amenities, including boat access points, spectator seating, and paved trails connecting key areas. The whitewater park of the project is strategically positioned near the Interstate 68 exit ramp. This strategic location not only promotes accessibility but also fosters greater integration with nearby businesses and local accommodations. The trails play a crucial role, weaving into the Greater Cumberland trail network along both

Maryland and West Virginia riverbanks. With connections to the Towpath, a river trestle, and a tunnel, these trails offer diverse recreational opportunities. Building upon existing assets like Canal Place, Cumberland's infrastructure, and local businesses, the river park extends services, creating a dynamic space for recreation and supporting related businesses. This report delves into the detailed analysis and feasibility aspects, envisioning a future where the River Park at Canal Place is a thriving symbol of community vibrancy and natural beauty.

B. Project Scope

To further completion of the project, Recreation, Engineering, and Planning (REP) and

Civil and Environmental Consultants, Inc. (CEC) were tasked with creating a 30%

Preliminary Engineering Report and revised masterplan that will be necessary to determine and redefine the locations of the feature water drops and related land-based trails connections. To generate the 30% report and design, the following items are necessary:

• Existing site topographic base mapping, bathymetry upstream of dam, 3D modeling of dam and other in-water man-made features.

• Hydrology Analysis

• Hydraulic Model Review

• Floodplain Feasibility Analysis

• Pertinent project site and surround area connections data

• Meetings/Coordination with United States Army Corps of Engineers

(USACE), City of Cumberland, Canal Place, and Allegany County

2. SITE ANALYSIS

A. Existing Site Photographs

Existing Aviertt Street floodwall and Levee.

Proposed whitewater launch point.

View of Ridgely Flood control wall and Bridge Street Crossing.

Proposed trail intersection with Bridge Street.

Existing floodwall and dam on river left (Maryland).

Proposed location of trail underpass adjacent to feature whitewater drop.

Existing Interstate 68 Bridge parking lots on Greene Street.

Proposed area of shared use parking for the river park.

Existing Riverside Park includes National Road 0-mile marker, George Washington’s

Headquarters. Proposed location of parking lot access for take-out location for whitewater park and the relocation of George Washington’s Headquarters to the point of the Riverside Park.

Existing Pedestrian Bridge with stairs and ADA access from Station to Riverside Park. Proposed connection point to Western Scenic Railroad Parking lot and Chesapeake & Ohio Bike Trail.

Existing flood wall River Left (Maryland side) downstream of railroad trestle. Proposed area for overlook and stair access to river trails.

Existing overlook connected to the C&O Bike Trail. Proposed ADA access ramp to riverside trails.

Existing gravel access to overhead electric lines on WV-28 Veteran’s Memorial Highway.

Proposed asphalt turnaround with parking for downstream of whitewater park boat launch points and access to the trail network from the Ridgeley, WV side of the North

Branch of the Potomac River.

Existing shared use gravel parking area adjacent to WV-28. Proposed shared use parking for use for downstream of whitewater park boat launch points and access to the trail network from the Ridgeley, WV side of the North Branch of the Potomac River.

B. Site Opportunities & Constraints

1. Opportunities

1. Economic Development:

The incorporation of new biking and hiking trails, fishing habitats, whitewater features, and observation areas within the project area is a significant expansion of recreational opportunities, reunifying both cities (Cumberland, Maryland and

Ridgeley, West Virginia) through their use of the river, providing an easy escape to the natural environment within the confines of an up-and-coming city built upon the rich history of its past and is a one-of-a-kind opportunity for the region that will produce continued economic growth and development.

2. Historic Features and Tourism:

Building on the existing success of the C&O Canal Towpath, National Historic

Park, the National Road, and the Downtown Cumberland Historic district, the

River Park at Canal Place is strategically positioned to draw from the rich historical tapestry of the region, offering visitors a distinctive and educational experience. The project's adjacency to key attractions, including the Great

Allegheny Passage Trail, Chesapeake and Ohio Canal Trail, Knobley Tunnel, Western Maryland Scenic Railroad, Canal Place businesses and event space, and the historic canal, creates a compelling foundation for recreational and tourism development.

3. Innovative Whitewater Features:

The proposed whitewater park which includes concrete and boulder features to create a unique manmade whitewater rapid structure that offers a distinctive recreational experience, attracting a broad spectrum of users, from novices to advanced enthusiasts. Intertwining riverside trails that bring spectators right next to the whitewater action and provide access to passive seating areas on nearby hillsides providing multiple interaction points.

4. Trail Network Integration:

The comprehensive trail network provides opportunities for exploration, connecting to existing trails like the Towpath and GAP Trail and introducing users to unique features such as the whitewater area, Knobley Tunnel, and railroad trestle. The trail networks will create a series of loops of varying length for users to create their own trail network that best fits their timeframe for a quick or longer ride, while enjoying different views for the extent of their ride back to their starting point.

5. Adaptive Reuse of the Dam:

Turning the once-perceived dam obstruction into a recreational opportunity exemplifies adaptive reuse. Although removed, the whitewater feature drops will continue to play a crucial role in the success of the Canal Re-watering

Project. Additionally, the integration of fish passage routes through the dam will grant various fish species access upstream for the first time since its construction in the 1950s.

2. Constraints

1. Sediment Contamination:

Historical studies indicate sediment contamination, specifically dioxins, behind the dam, necessitating careful consideration and involvement of regulatory authorities like Maryland Department of the Environment (MDE).

2. Historical Building Relocation:

The relocation of George Washington’s Headquarters is suggested due to its lack of significant historical value in the current location, introducing potential challenges in finding a suitable and historically appropriate site.

3. Infrastructure Adaptation:

The proposed changes to the dam and adjacent areas necessitate careful planning to ensure the integration of new and existing infrastructure, including existing

Combined Sewer Overflows (CSO), proposed extension and capacity of CSO to the North Branch of the Potomac River, and other potential interactions that may come from project construction.

4. Site Morphology:

The elevation changes and natural morphology of the site need to be considered in the design process to ensure the safety and accessibility of the proposed features including the connection to upland and riverside ADA accessibility options and trail designs.

5. Regulatory Approvals:

The project requires compliance with various regulatory requirements, including permits, zoning regulations, and legal considerations, which may pose challenges in terms of timelines and a lengthy approval process for construction.

6. Historic Preservation:

Balancing the need for progress with the preservation of historic sites and structures requires a nuanced approach to ensure the cultural integrity of the region is maintained or accentuated.

7. Public Safety:

The inclusion of in-water features, particularly whitewater features, necessitates careful design to ensure public safety, especially for users with varying skill levels.

C. Hydrology

The availability and timing of flow is one of the most important factors in the performance and function of a river park, and a key factor in design. The North Branch of the Potomac River in Cumberland is a relatively large river with discharges that vary dramatically throughout the year. The character of the park will change with various flows, but generally there is enough flow to provide for quality river recreation features throughout the year. Many popular river parks have similar flow regimes, designed to function down to 300 cubic feet per second (cfs) or even less. These same features can be designed to also function well at higher flows with increased performance for advanced paddlers and surfers.

River discharge data was downloaded from the publicly available USGS gage station

01603000, North Branch Potomac River Near Cumberland MD, located near the Canal

Parkway bridge a little over 2 miles downstream of the project site. At the downstream end of the project area is the confluence with Wills Creek, which contributes significant flow to the river. Discharge data from Wills Creek was downloaded from USGS gage station 01601500. In order to estimate the flow in the North Branch Potomac upstream of the confluence, flow data from Wills Creek was subtracted from the North Branch

Potomac gage data to create a time series of flow data for the North Branch Potomac upstream of Wills Creek.

For the purposes of this study, REP analyzed the average daily discharge for 30 full calendar years, 1993 through 2022. This provides a relatively large sample of data from the modern watershed. Older discharge data may not accurately reflect current watershed dynamics due to development, increase in impervious surface area, and other factors.

Mean daily flow time series for the 30 calendar years analyzed (1993-2022) for the North Branch Potomac upstream of Wills Creek. The river typically flows between 300 and 3,000 cfs, though high flow events have occurred ranging from over 10,000 cfs to over 20,000 cfs.

The complete time series of the daily flow data for the last 30 full calendar years is shown above. Flows in the river can vary dramatically from year to year, depending on precipitation and snowmelt. Generally, flows are higher in the winter and spring months

(January – May) and lower in the summer and fall (July – October). However, high flows can occur at any time of the year as evidenced by the highest flow recorded on September

7, 1996. On that date, the flow peaked at 21,230 cfs, the highest flow calculated for the

North Branch of the Potomac upstream of the confluence with Wills Creek.

Exceedance probabilities offer a valuable method for determining typical flows and were computed for every calendar month. The 75% exceedance probability (lower quartile flow) represents the flow that surpasses 75% of the recorded daily flows in that month.

Similarly, the 50% exceedance probability (median flow) is the flow eclipsed by 50% of the recorded daily flows, while the 25% exceedance probability (upper quartile flow) denotes the flow exceeded by 25% of the recorded daily flows in that month.

The accompanying plot illustrates these flows for each month, connecting the median flow with a blue line and shading the area between the upper and lower quartile flows in light blue. This shaded region encapsulates the middle 50% of recorded flows for each month, offering a reliable indicator of the typical flow range anticipated throughout the year.

The median flows for February through May are all above 1,000 cfs, while the median flows for July through November are all below 400 cfs. A table summarizing the monthly statistics developed is shown on the following page. The month where the minimum daily flow was recorded is January (20 cfs), although this month has also recorded high flows

Monthly median, upper quartile, and lower quartile daily flows calculated for each month of the year based on mean daily flow data from 1993-2022, based on the calculated flows in the North Branch Potomac River upstream of the confluence with Wills Creek.

up to 10,200 cfs. This demonstrates the annual variability in flows depending on the storm cycles that move through the watershed.

Numerous established river parks with comparable flow patterns have achieved success.

Leveraging the expected flow conditions, the proposed enhancements for river recreation can be tailored to perform effectively throughout a significant portion of the average year.

In the winter and spring, characterized by higher flows, the project can be configured to offer accessible whitewater suitable for everyone from beginners to advanced paddlers.

As the flow decreases in the summer and early fall, the river features may be less enticing for advanced users, but the same structures can be designed to accommodate tubing, boat passage, and novice whitewater activities. Riverside recreation, encompassing activities such as fishing, strolling, picnicking, biking, splashing, and wading, will be available year-round. The project is intended to facilitate fish passage at all expected flows while creating a habitat for aquatic species.

D. Floodplain Feasibility Analysis

The floodplain feasibility study work has not been performed, as the necessary existing hydraulic models of record have not yet been received from the US Army Corps of

Engineers (USACE). The necessary information has been requested through a Freedom of Information Act (FOIA) request.

Floodplain and flood flow conveyance are important considerations for this location on the North Branch Potomac River (and Wills Creek) in Cumberland. Levees, floodwalls and other flood flow conveyance infrastructure exist at the site and trails have been constructed atop areas of flood protection infrastructure. The floodplain feasibility analysis will ensure the proposed project can be built without causing adverse impacts to the regulatory floodplain.

A preliminary level proposed conditions hydraulic model will be created to represent the

Industrial Dam modification and river recreation park concept, and water surface elevation results will be compared to the effective model for the reach. Model results will determine if the proposed project can be implemented without adverse impacts to the floodplain. To conduct the formal floodplain analysis necessary for permitting, further topographic / bathymetric survey will be required, and the design will need to be progressed to at least the 60% design level.

E. Dam Structural Analysis

Based on a review of the available record drawings (See appendix section for drawings and figures), it appears that the bridge pier and abutments were not designed to have connection to the dam. The construction drawings do not indicate a positive connection between the two structures (e.g., steel dowels or other reinforcing steel configurations).

Instead, the two structures were to be separated by an expansion joint (filled with ¾” premolded expansion joint material). A 9” wide, vertically oriented waterstop was also included at the joint to minimize water infiltration through the joint.

Although it is not possible to verify that the design of the piers and abutments accounted for the location of the dam “infill” for any lateral stability without reviewing the original calculations (which are not available), given the construction means and the intentional expansion joint between the structures, it is unlikely that it was considered. In order to construct the abutments and pier as designed, it would have been necessary to have constructed these structures prior to placement of the dam concrete. As such, the design would have been considered a period of time prior to and during the construction of the dam that those structures would have been without the lateral support of the dam or the bridge superstructure.

Therefore, it is our opinion that the removal of portions of the dam will not adversely affect the performance of the bridge piers and abutments. Removal of the concrete near the interface between the structures to remain should be demolished with means that will ensure that incidental impacts will not occur (e.g., cutting rather than hammering). Given that the concrete in the dam appears to have been designed with some reinforcing steel, cutting of the concrete is the recommended approach.

Since the available record drawings are labeled to be “as built”, the discovery of connection between the dam and the pier or abutments is not anticipated. Nondestructive test methods (e.g., x-ray or ground penetrating radar) can be used prior to demolition to ensure such connections were not included. However, it is unlikely that such undocumented changes would have occurred in this case.

F. Aquatic Species

The Potomac Industrial Dam has a profound impact on historic migration corridors and spawning habitat. Dams and other manmade barriers have resulted in stream fragmentation limiting movement of resident fish and migrations of catadromous

(migrate down rivers to the sea to spawn) and anadromous (migrate upstream of a river to spawn) species, including the American eel, to their historical spawning and nursery habitat. In turn, the dam likely limits the abundance and diversity of mussel species in the impounded zone behind the dam due to a lack of fish host and habitat impairments.

The Maryland Department of Natural Resources (MDNR) indicated that it has been assumed that mussels have long been extirpated or, if extant, few species remain, and they persist in very low numbers in the North Branch Potomac River (McCann, 2021).

The Potomac Industrial Dam has been identified as a high priority blockage for resident fish species and a moderate priority blockage for catadromous and anadromous species.

Though there are six downstream barriers from the Potomac Industrial Dam, with one having a fish ladder and another being notched, the American eel has been documented downstream of the Potomac Industrial Dam but not upstream. According to the MDNR, the section of the North Branch Potomac River from Westernport downstream to Pinto remains cold and suitable for trout management (MDNR, n.d.). The impounded zone behind the Potomac Industrial Dam is likely impeding the trout population in this reach.

G. Construction Feasibility

In-river construction presents a set of unique challenges. Based on extensive experience designing and overseeing many similar river projects throughout the country, the design team believes the proposed project is constructable in a manner that can minimize the impact to the river. Detailed phasing and water control plans will be developed in future project phases and will change as the design progresses, but the overall approach will include:

• Placement of temporary cofferdams to isolate work areas. The existing dam may be used temporarily as a cofferdam. Pump water to dewater the work area.

• Allow space for river flow to pass around the isolated construction areas.

Working in a single channel river such as this, the drop structures will need to be constructed in phases, with a portion constructed in the dry and then the river

“flipped” with flow passing over the recently constructed portion while the rest of the structure work area is dewatered.

• Turbidity curtains, care of water area, and other best management practices

(BMPs) designed to limit excess turbidity in the river.

H. Sedimentation Analysis

The Potomac Industrial Dam has interrupted the North Branch Potomac River’s natural sediment transport process resulting in sediment accumulation in the impounded zone behind the dam. Princeton Hydro estimated the impoundment to be approximately 1.9 miles long with an estimated accumulated sediment volume of 142,000 cubic yards

(Wildman, 2010, reported in Van Ryswick and Sylvia 2015). The dam was constructed to supply water to local industry; however, this past industrial activity created concerns regarding the chemical and physical properties of the accumulated sediment, leading stakeholders to sample and analyze the sediment for contaminants.

As part of a feasibility study for removal of the Potomac Industrial Dam, Princeton Hydro collected three surficial sediment samples within the impounded zone behind the dam in

2009. The results of these sediment samples showed the presence of low levels of dioxin and dioxin-like compounds in surficial sediments in the impoundment. Due to the results of this study, American Rivers contracted the Maryland Geological Survey (MGS) to perform a more detailed sediment study within the impounded zone of the dam to determine the physical and chemical properties of the sediment and the areal extent and depth of dioxins and metals in the sediment (Van Ryswick and Sylvia 2015). MGS collected 10 sediment core samples, ranging from 1 to 3.4 meters deep, from the upstream impoundment area. Various depth intervals were analyzed for grain size, elemental concentration, extractable metals, and dioxins.

The following summarizes the findings of the study:

1. Upper sediments that accumulated after construction of the dam predominantly consist of gravelly sands. Fine muddy sand and mud sediments have accumulated in low energy areas close to the shore and along river left just above the dam. Gravel and cobbles increase in the deeper sediments, indicative of the pre-dam high energy streambed.

2. Total elemental concentrations in the sediments are within the ranges of other dam impoundment sediments from similar settings.

3. Toxicity characteristic leaching procedure (TCLP) analyses for extractable hazardous metals were run on the finer sediments at various intervals in the cores indicative of post-dam deposition. MGS found that the TCLP metals concentrations were either below the detection limit or well below hazardous metal threshold concentrations; therefore, MGS concluded that there were no concerns associated with TCLP metals in the sediments within the impounded zone.

4. The sediments were analyzed for a suite of dioxin compounds. Since the toxicity of individual dioxins varies by orders of magnitude but have a similar mode of action, the concentration and toxicity of individual dioxins were standardized to the most toxic dioxin, 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and presented as the Toxicity Equivalent (TEQ) dioxin concentration. Dioxins were found in all the sediment samples, with lower concentrations in coarser sand and gravelly sand sediments and higher concentrations in finer grained mud and organic sediments.

Dioxin levels generally decreased in the pre-dam sediments dominated by gravelly sands and cobbles. Dioxins concentrations were generally lower farther upriver from the dam except in Core 8, which was taken in a finer sediment accumulated near the river right bank edge.

5. The TEQ dioxin concentrations in the sand and gravelly sand samples were below or just above the level of low risk to sensitive mammalian wildlife. The TEQ dioxin concentrations were highest in the very muddy sediments of Core 2 along the left bank just above the dam, where two samples contained TEQ values above the EPA level of high risk for sensitive avian wildlife.

I. Canal Water Intake Analysis

The existing canal water intake system is a necessary component of the Canal Rewatering

Project. Currently, the first 0.25 miles of the proposed 1.20-mile canal reconstruction has been completed. The water intake system as constructed was designed to meet the rewatering requirements of the 1.20 miles of canal reconstruction. As the project stands as of this report, the required water for rewatering the canal is only needed as makeup water for water lost out of the canal. The capacity required for the total 1.20 miles is 8 cubic feet per second or approximately 3,600 gallons per minute.

There is an intake screen structure located in the reservoir formed by the Corps Dam at an elevation of 606.25 feet mean sea level (MSL). The water flows via gravity through a 24-inch water line into a sluice gate to the wet well of the pumping station. Two 75 HP submersible pumps move water through two 10-inch discharge pipes, below the pedestrian bridge to the can turning basin. A float switch cluster is located near the canal in a stilling structure that controls the pumps by allowing them to come on and off at various water levels.

When the dam is removed, the water level at the existing intake location may fall below required levels. Modifications/relocations will need to be made to the intake to ensure proper water levels if/when the Canal Project extends to the proposed 1.20 miles. The design options are shown in the preliminary design section of this document.

J. Combined Sewer Overflow (CSO) Outlet Structure The proposed future construction of an upgraded larger CSO structure (a part of the

Canal Re-watering Project) downstream of the proposed whitewater park has been coordinated with the design and intent of this 30% Preliminary Engineering Report, however continued coordination may be necessary as both projects mature towards construction.

K. Upland Analysis

Parking

Greene Street Interstate 68 Bridge Underpass – Below the Interstate 68 Bridge

(Clarysville Bridge), includes three distinct asphalt paved parking lots between S Johnson

Street and Bridge Street Intersections. Parking areas nearest to the S Johnson Street intersection and Bridge Street intersection are shared use parking for businesses on both sides of Greene Street. The middle parking lot is a metered public parking lot (Parking

Lot #3) and is the designated parking lot for the National Road Monument and George

Washington Headquarters.

South Mechanic Street – Two asphalt public parking lots with striping serve the public.

One adjacent to the Western Maryland Scenic Railroad Station/ and Canal Place Heritage

Area and one below the Interstate 68 bridge at the intersection of Howard Street and

South Mechanic Street. Both parking lots serve as overnight/long-term parking for users of the GAP and C&O Trail systems as well as parking for the Shops at Canal Place and stage great lawn area. It also serves as additional parking for the Cumberland Pedestrian

Mall and greater downtown area.

Route 28 (Veterans Memorial Highway), WV- Blocker Street Utility Road – At the end of Blocker Street located near the railroad trestle serves as an existing access point for u

Route 28 (Veterans Memorial Highway), WV – A gravel overflow area serves as additional overflow parking directly across from a small business plaza currently housing

Chef Paul’s Kitchen & Catering, My Place, and J&B’s Quick Stop Drive Thru. Adjacent to the overflow parking area is a car dealership, Nelson Auto Sales. The gravel lot can hold approximately 20-25 vehicles.

River Access

There are multiple launch ramps for boating along the North Branch of the Potomac

River upstream and downstream from the industrial dam. Unfortunately, the inability to pass through Cumberland’s industrial dam has been a stumbling block for long distance river trails. With the removal of the industrial dam, a user could now paddle from

Jennings Randolph Lake near Westernport, Maryland 147 miles to Sharpsburg, Maryland. Providing an expanded user group to lodge and board in Cumberland as they make their excursion down the Potomac River Water Trail.

Local area launch ramps docks and ramps are located below:

Alleghany County Fairgrounds Boat Ramp

Location: Lat: 39.607549 Long: -78.803939

Miles to downstream launch/take-out point: 2.70 miles

Upper Potomac Industrial Park Boat Launch

Location: Lat: 39.634237 Long; -78.797227

Miles to downstream launch/take-out point: 2.15 miles

Whitewater Park Launch

Location: Lat: 39.647570 Long: -78.768506

Miles to downstream launch/take-out point: 0.30 miles

Whitewater Park Take-out

Location: Lat: 39.648074 Long: -78.764786

Miles to downstream launch/take-out point: 0.20 miles

Canal Place Stage Launch

Location: Lat: 39.645972 Long: -78.764318

Miles to downstream launch/take-out point: 2.72 miles

Mason recreation Boat Ramp

Location: Lat: 39.619571 Long: -78.762443

ADA Accessibility

ADA accessibility from the Western Scenic Railroad Station to Howard Street is carefully planned for seamless inclusivity. Originating at the ADA parking lots near the

GAP/C&O Trailhead Junction, a wide ADA ramp encircles the Canal Park Stage, extending to a pedestrian bridge over the canal and an overlook along the Chesapeake and Ohio Bike Trail. Access to Riverside Park is facilitated by an ADA ramp from the south side of the Railroad Station building, connecting to the train station platform. The platform features an ADA crosswalk for safe passage over train tracks, leading to an additional ADA ramp connected to the pedestrian bridge. This strategic design ensures uninterrupted and barrier-free access, prioritizing the diverse mobility needs of individuals from Howard Street to the Western Scenic Railroad Station and to future planning endeavors along the North Branch of the Potomac.

Trail Connections

The junction of the Great Allegheny Passage (GAP) Trail and Chesapeake and Ohio

Canal (C&O) Towpath Trail in Cumberland, Maryland, serves as a pivotal point for economic development. This convergence transforms Cumberland into a thriving tourist hub, attracting outdoor enthusiasts and bikers. The city strategically provides amenities such as bike rentals, accommodations, and restaurants to cater to trail users, fostering business growth. Cumberland's historical significance is heightened as it marks the transition from the industrial C&O Canal to the scenic GAP Trail. The economic impact is evident in increased patronage for local businesses, job creation, community engagement, and infrastructure investment. Overall, the trail junction enhances

Cumberland's appeal, showcasing a successful model of economic development driven by outdoor recreation and cultural exploration.

3. PRELIMINARY DESIGN IMPLEMENTATION

A. Whitewater Park Design

IN-WATER DESIGN: In the proposed river recreation park's water design, the intricacies of each instream recreational drop structure are meticulously planned to offer a dynamic and engaging experience for a broad spectrum of users. The natural stone boulders, with a minimum diameter of 3 feet, are strategically arranged and anchored to the riverbed where necessary, ensuring stability during varying flow rates. The variability in dry drop (1.5 to 3 feet) caters to users of different skill levels, making the park accessible to both beginners and advanced enthusiasts. The upstream-most drop structure, designed to mirror the water surface elevation of the existing dam, serves as a key element in maintaining consistency and preserving the impoundment created by the Industrial Dam.

A casual river surf scene at a dam modification project in

Dayton, Ohio. This surf structure shown is anchored directly to a defunct low-head dam.

A whitewater park on the Arkansas River in Salida, CO. The park is utilized by a wide range of people and abilities and has been credited with driving significant economic growth.

A beginner kayaker descends a recreational drop structure in

San Marcos, Texas designed by REP. These structures perform together with, and are anchored to a defunct mill dam, a common site scenario and opportunity for river recreation.

The incorporation of fish passage channels at each drop structure demonstrates a commitment to ecological considerations.

The un-grouted natural stone channels, specifically designed for low-flow conditions, aim to facilitate the movement of target fish species across the park. The pools between the drop structures not only provide a visually appealing cascade effect but also ensure a well-thought-out recovery time, contributing to the safety and enjoyment of users. The stone bank terracing further enhances the aesthetics of the water design, creating areas of focus for spectators and users alike.

Riverside Design: The riverside design of the park intricately weaves together accessibility, safety, and environmental sensitivity. The ADA accessible trails, constructed with durable riverside concrete, offer users the opportunity to traverse the length of the project seamlessly. The deliberate positioning of the trails close to the river’s edge provides not only scenic views but also enhances user experience, allowing them to feel connected to the water throughout their journey.

Trail underpasses at the existing "Blue Bridge" roadway bridge ensure a continuous and uninterrupted path for users.

The flood-resistant design of the trails acknowledges the dynamic nature of the river, accommodating potential inundation during high flows. Multiple ADA accessible river access points, strategically placed upstream and downstream, serve as pivotal entry and exit points for various water activities, fostering a sense of convenience and inclusivity. Stone river access steps, seamlessly integrated into the stone bank terracing, add an aesthetic touch while providing functional access to the water's edge. The emphasis on preserving existing infrastructure not only ensures continuity with the surrounding environment but also minimizes the project's ecological footprint. This comprehensive riverside design is a testament to the project's commitment to creating a harmonious and sustainable river recreation park.

B. Upland Design

All the site areas outside of the immediate water course are included in the upland design.

Proposed structure and design elements including parking facilities, trail heads, trails, seating areas, viewing areas, historical features, fishing access and connections to existing infrastructure are a part of this section.

Trail System: Expanding on the achievements of the C&O Canal and the Great

Allegheny Passage Trail Systems, the proposed upland trail network aims to establish connections with national, regional, and local trail systems. Nationally, it integrates with the C&O and Great Allegheny Passage trail systems, while regionally, it connects to

Carpendale, WV, the presently closed Knobley Tunnel, and potential future rails to trails connections. At the local level, the 1.9-mile Maryland loop trail offers wetland paths and fishing access points along the river. The system includes larger loop trails with smaller loops, providing diverse experiences and scenic views. This integrated trail system is

Stone terracing and river access at a dam modification project in Calgary, Alberta.

designed to facilitate the reconnection of cities with their waterfronts, a prospect not realized for generations.

Parking: There are four proposed parking facilities providing river and trail access. They are integrated into the city’s fabric and are multi-use facilities.

Greene Street Interstate 68 Bridge Underpass – Below the Interstate 68 Bridge

(Clarysville Bridge), includes three distinct asphalt paved parking lots between S Johnson

Street and Bridge Street Intersections. Parking areas nearest to the S Johnson Street intersection and Bridge Street intersection are shared use parking for businesses on both sides of Greene Street. The middle parking lot is a metered public parking lot (Parking

Lot #3) and is the designated parking lot for the National Road Monument and George

Washington Headquarters. It is anticipated that this will be additional parking for guests and users of the whitewater park and trails.

South Mechanic Street – Two asphalt public parking lots with striping serve the public.

One adjacent to the Western Maryland Scenic Railroad Station/ and Canal Place Heritage

Area and one below the Interstate 68 bridge at the intersection of Howard Street and

South Mechanic Street. Both parking lots serve as overnight/long-term parking for users of the GAP and C&O Trail systems as well as parking for the Shops at Canal Place and stage great lawn area. It also serves as additional parking for the Cumberland Pedestrian

Mall and greater downtown area. It is anticipated that users of the whitewater park and trail system will utilized this areas for parking.

Blocker Street parking facility and emergency access-. Located on the Ridgely, WV side of the river, this existing access point could be expanded and developed into a 7-space trail head providing parking, emergency access, and ADA accessibility to the river.

WV-28 Shared use river access point. This existing gravel lot off WV-28 along the levee in Ridgely, WV can provide river access to boaters and ADA access to hikers and fishermen.

River Left North Branch of Potomac River

Whitewater Launch Trailhead: Includes the Avirett Avenue trail linkages and boater access to the whitewater park launch area. This trail head provides access to the top of the levee trail, the river side trail, and the boat launch area.

Top of the Levee Trail- This trail follows the existing levee creating a strong connection along the entire length of the whitewater park linking the launch area and the takeout area with multiple access points into the city and down to the riverfront. The trail offers outstanding views of the river, city, and surrounding countryside. In addition, the trail is almost entirely ADA compliant.

Riverside Trail: The riverside trail system provides direct access to the waterfront linking the beach, viewing, and seating areas along the riverfront. There are three access points down to the riverfront, however the middle access point allows for ADA accessibility to the riverfront.

Connections to Existing Pedestrian Systems: Where the top of the levee trail crosses the blue bridge, there is a proposed crosswalk providing a strong sidewalk connection into the city.

Blue Bridge Underpass: As the riverside trail passes under the blue bridge, an outstanding environment is created. Focused on the largest drop in the water park and bringing the trail close to the rushing water, letting bystanders experience the sound and feel the rushing water in close connection to whitewater enthusiasts.

Terraced Rock Seating Area: Located in a natural bowl focused on the last two feature water drops in the water park, this feature provides the ideal viewing area of the park.

Whitewater Park Take Out Area: The takeout is located at the end of the whitewater park, providing a calm area to take out. It also provides access along the levee wall to the top of the levee trail, providing direct access to the launch area, relocated Washington’s headquarters and connections into town via the pedestrian bridge to canal place or road connections via Greene Street.

Proposed Observation Platform and Stairway: The proposed viewing platform will be located on an existing foundation structure and will provide panoramic views of the river, city and, countryside while the stairway will also provide access to the riverfront.

Proposed ADA Ramp for River Access: Located adjacent to the existing observation platform this ramp will provide water access.

Waterfront Trail: The waterfront trail provides ADA access to beaches, hiking, and fishing opportunities along the calmer portion of the river.

Creating Fishing Opportunities Around River Deflectors: Along the waterfront trail access, fishing areas are created in and around the diversion structures, providing great eddies and low current for fish to congregate as they move up and downstream.

Connection to the Maryland Loop Trail: This 1.9-mile trail explores wetlands and river environments down river and be able to loop back to the beginning of the trail.

River Right North Branch of Potomac River

Proposed expansion of the waterfront trail upriver to Carpendale, WV, includes a trail connection in Ridgely, WV, at the blue bridge. This involves establishing a crosswalk and sidewalk connections to link the town with the riverfront. Specific features of the plan include:

Blue Bridge Underpass on WV Side: Details regarding the underpass at the Blue

Bridge on the West Virginia side.

Trestle Bridge Underpass: The walkway provides trail users to access upstream and downstream of the whitewater park without the interaction of pedestrians and the active railroad line. Occasionally, a user may be fortunate enough to be below the trestle when a train rumbles across overhead.

Emergency Access ADA Parking and Access: A secondary location for users to park and access the riverfront trails from WV-28 and used for emergency access as needed.

Boat Launch Access on WV-28: The inclusion of a boat launch access point from WV-

28 will provide water enthusiasts to access the calmer portions of the river and allow a gentle ½ day float trip to the Mason boat Launch take out.

Waterfront Trail: The main waterfront trail facilitating activities such as viewing, hiking, fishing, and access to beaches along the waterfront.

Connection to Trestle Loop Trail Downriver: Establishing a connection to the Trestle

Loop Trail downstream.

C. Water Intake Design Options

The following options to be examined prior to the dam’s removal:

• A slip stream constructed on the side of the river below trail surface to provide necessary depth to cover intake screen.

• Intake screen to be relocated upstream before the first feature drop, anchored into the designs of the feature’s wingwalls.

• Water intake location to remain in place, but installation of a smaller pipeline within the 24-inch pipeline to be pumped rather than gravity fed.

D. Sediment Dredging/Passive Release Design Options

Sediment Dredging Option: Following permit approvals, the first step of project implementation will be to mobilize equipment for the installation of MDE-approved erosion and sediment control measures and best management practices. Existing high value natural resources located in the work area will be demarcated to avoid unanticipated disturbances. Given the setting of the Bank, multiple ingress and egress locations exist that could be utilized to mobilize equipment. A mobile dredger will be brought in to begin the process of excavating deposited sediment from the reservoir behind the dam to prevent the release of contaminated sediment to the downstream channel. The removal of accumulated sediment will be planned and executed with approaches that will mitigate deleterious effects on aquatic life. The dredging program including the type of dredge, rating of pumps, location, and depth from which the sediment is to be removed, will need to be determined.

It is anticipated that the dredging activity will generate approximately 142,000 cubic yards of waste requiring disposal. The disposal of the dredged material will be conducted in compliance with federal, state, and local government laws and regulations.

Passive Sediment Release Option: To avoid undue harm during dam removal, deconstruction will be undertaken in careful steps to not only avoid downstream degradation but also to maintain public safety and the structural integrity of the Blue

Bridge, which is co-located with the dam. Though it has been determined that the bridge and dam are not structurally connected, the decommissioning will be completed in coordination with the State Highways Administration.

The project will involve dam removal to allow certain structures to remain in place, without reservoir impoundment or hazards to the Blue Bridge or recreational boaters. The dam will be removed as stated in the design section of this document, while leaving the center pier for the bridge in place. The pier will be stabilized, along with the streambed within the footprint of the former dam, to provide a suitable hydraulic section for velocity control and fish passage.

Removing the dam will generate short-term, temporary geomorphic disturbances during the passive release of the remaining sediments from the impoundment. Shifts in patterns of sediment movement can be a prominent ecological response to dam removal and these changes in transport control the process of channel evolution, which can also have important consequences for biogeochemical cycling. Additional modeling will need to be completed to determine the channel evolution and associated rates of sediment delivery.

Per the following case study. the Bloede Dam Biogeochemical Impacts Analysis Report

(Boynton, et. al., 2014), which assessed phosphorus inputs to the ecosystem associated with sediment release from removal of the Bloede Dam. This analysis assessed how particulate phosphorus would interact with the estuarine segments of the Patapsco River, with the most basic distinction being between inputs of total particulate phosphorus and inputs of particulate phosphorus forms that could be converted into forms that could grow algae. The analysis concluded that there would be a reasonable expectation that release of sediment from the Bloede Dam could result in 1) the deposition of inorganic phosphorus in sediments of the tidal Patapsco River and that 2) under saline, and especially low oxygen conditions, a portion of that phosphorus could become bio-available for the growth of algae

(Boynton, et. al., 2014). However, it is important to note that these release rates were related to the area of deposition; if the area of deposition of fine-grained material were spread out over the whole tidal Patapsco, then the releases would be aerially moderate.

Ultimately the study concluded that a significant phosphorus release was not anticipated.

Based on this study and the anticipated removal of sediment from the impounded zone behind the dam, it is anticipated that the same discountable phosphorus release will be associated with the Potomac Industrial Dam.

Low-head dams not only affect the downstream sediment supply and biogeochemical cycling processes, but they also have potential implications associated with flooding.

These effects associated with the removal of a low-head dam can include both direct effects associated with changes in riverine hydrology and indirect effects related to potential changes in river morphology. The Potomac Industrial Dam does not provide a flood control function and the deleterious effects of its removal on flooding will likely be minimal. The accumulated sediment in the impounded zone decreases the reservoirs’ ability to store floodwater and its removal is anticipated to result in reduced flood elevations upstream due to the loss of backwater effects. Indirect effects of low-head dam removal are generally associated with changes in river morphology, which could result in increased flood elevations associated with a sediment release that exceeds the channel’s conveyance capacity.

4. CONCLUSION & NEXT PHASES

Based on the assessment described in this report, a river recreation park at the site of the

Industrial Dam is feasible from a technical perspective (pending the floodplain feasibility analysis), as shown in the preliminary design developed.

To progress into the detailed design phase, additional data will need to be collected including additional topographic and bathymetric survey, water level logger install and data analysis, and a sediment assessment. It is recommended that this additional data collection is scheduled in late summer / fall 2024 while flows in the river are low.

Below is a summary of the next technical steps required to bring the design through 60% design and regulatory permit application submittals:

Topographical Survey: Additional surveying including a detailed bathymetric survey will be necessary beyond what has been collected to date.

Water Level Loggers: Installation of water level loggers at multiple locations in the project vicinity to record water surface elevations. It is important this task occurs during low flows prior to the next high flow season, as the water surface elevation data collected is needed for the full range of flows from low to high. This data is used for calibration of the design hydraulic model and needs to be collected prior to detailed design hydraulic modeling.

Sediment Assessment: An assessment of the impounded sediment upstream of the dam will be necessary to advance the design. The sediment assessment would entail rod probing to refusal throughout the sediment assessment area to estimate sediment depths, sediment type, and underlying material characteristics.