riverside dam presentation june 18, 2013 @ knights of columbus hall

7/28/2019 Riverside Dam Presentation June 18, 2013 @ Knights of Columbus Hall

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Public Information Centre No.2

Presentation of Alternative Solutions for Riverside DamClass Environmental AssessmentCity of Cambridge

une ,


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WelcomePresentation Outline1. Opening Remarks Kealy Dedman, Director, Engineering Services2. Main Presentation Ron Scheckenberger, Consultant Team PM

1. Introduction/Background

2. Baseline Inventory3. Study Progress and Timeline Since First Public Session4. Problem and Opportunity Statement5. Selection of Alternatives

Riverside Dam Class Environmental Assessment

6. Assessment of Alternatives7. Legislative and Regulatory Requirements8. Costs and Liabilities9. Frequently Asked Questions (FAQs)

10. Next Steps3. Closing Remarks George Elliott, Commissioner of Transportation and

Public Works4. Breakout to Work Stations Anne McIlroy, Public Facilitator


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WelcomePublic Information Centre Outline

After the presentation individuals can visit Work Stations to view thepreliminary alternatives and to ask questions and provide comments

directly to City Staff and Consultant Team members

Each Work Station is the same and includes:- Drawin s that illustrate each of the reliminar alternatives


- City Staff and Consultant Team Members to facilitate a discussion,answer questions and take notes


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1. Introduction and Background

Sulphur Creek

Riverside Park


Riverside Dam


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Riverside Dam constructed in the late 1800s tosupport Erb Mill

Maintenance of structure likely ended once the

dam and associated mill race were no longerrequired to power the mill

Over time Dam has deteriorated to current state 2008/2009 study (Sanchez) determined dam to



have elements in poor structural condition Emergency repair of south control structure

completed in December 2008

Provincial Ministry of Natural Resources (MNR)

permit stipulated requirement to build permanentworks under the Lakes & Rivers Improvement Actbased on the results of a broad basedinvestigation


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Riverside Dam is 1.5 m +/- high, 67 m +/-long concrete/rubble stone gravity dam

Two control structures previously controlled

water levels but are no longer functional The dam facilitates diversion of water flow to

the mill race which is conveyed under



,

P&H Milling has expressed an interest indecommissioning the mill race as it is nolonger required for the operation of the mill


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City has initiated the study using theProvincial MEA Class EnvironmentalAssessment process which guides decision

making for Municipal Infrastructure To direct and guide the study, the City has

formed:

- Project Team



- Technical Committee- Stakeholder Committee

Input has been received at strategic points inthe study process from each of the above


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2. BASELINE INVENTORY



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2. Baseline Inventory

As part of this study, the AMEC Team conducted numerous baselineassessments to develop a better understanding of the Riverside Dam andits local environs, these included:

land use park use

cultural heritage

structural engineering

hydrology (flows) hydraulics (levels)

water quality

sediment quantity and quality


geotechnical fisheries/aquatic habitat

vegetation

wildlife

topographic surveys (aboveand below water line)

stream stability


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Park Use and InventoryVarious components of the park include: The Speed River Interface Riverside Dam

Active Park Programming Passive Leisure Circulation (roadway) Built Heritage Features CP Rai l Line Roadway

(Shared Automotive and Pedestrian)

Parki n

Board Walk

Park Features (Uses + Buildings)

Heritage Features



Character Areas

Prominent Views

Internal Edges

Noise Disturbance

Trai ls


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Fish Community Mixed water fishery: cool water predators (pike),

warmwater based fishery One Species at Risk (SAR) fish identified

downstream of the study area - Silver Shiner(Notropis photogenis)

Mussel Community

Fisheries and Terrestrial (Vegetation/ Wildlife) Assessment



study area Wavy-rayed Lampmussel (Lampsilis fasciola)

Terrestrial (Vegetation/Wildlife) Community

The head pond upstream of Riverside Dam is documented by Guelph MNR as waterfowlwintering concentration area

Several regional/local significant natural heritage features adjacent to the study area Speed River Provincially Significant Wetland Complex, Blair-Bechtel-CruickstonEnvironmentally Significant Landscape, Speed River Significant Valleyland

No terrestrial Species at Risk (SAR) found during study, but potential for Butternut (Juglanscinerea) an endangered tree species - to occur within the study area


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Flood and Water Level Assessment

Flood flows and flood levels have previouslybeen determined by GRCA using computer

Speed River Flow Rates @ Riverside Dam (m3/s)Summer

Mean BaseFlow

RiversidePark Floods

2 YearFlood

10 YearFlood

100 YearFlood

RegionalStorm Flood

5 >45 110 181 269 679



Levels used to generate Regulatory floodplain Riverside Dam is understood to increase flood

levels 0.56 m and 0.58 m for the 100 year andRegional Storm floods, respectively

Floodplain includes a Two-Zone policy whichestablishes distinct regulatory restrictions onlocal development potential within the floodfringe vs. the floodway


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River Morphology (Physical Properties)Study Activities Built upon information from existing

studies

Examined the head pond as well asupstream and downstream channelreaches with a particular focus on thesediment that has accumulated behind the

Top of Bank Cross-section - Site 13

271

271.5

272

272.5

273

273.5

274

0 10 20 30 40 50

Width (m)

Depth(m)

14-Nov-07 Water Bankfull 28-Nov-11



dam Field work included re-measurement of

river stations set in 2007 to assess change

Findings

The river in the vicinity of the study area has not been overly dynamic The sediment within the reservoir has accumulated to approximately

13,000 m3

The sediment within the reservoir is finer than the surrounding reaches


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Water and sediment quality studies havedemonstrated the Riverside Dam causesthe following:

Decreased dissolved oxygenconcentrations in the head pond(below Provincial objectives)

Water Quality and Sediment Quantity/Quality



downstream A build-up of sediment with metals

(Cadmium, Copper and Zinc)exceeding Provincial standards

A sediment management plan would berequired for any future works affecting theRiverside Dam (Provincial Ministry of theEnvironment requirement)


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Survey of Dam and Head Pond As part of the study, a bathymetric (underwater

survey) investigation was conducted The depth of water to sediment versus former creek

bed in the dam head pond is important tounderstand the flow properties, flood depths as wellas the amount of sediment for potentialremediation/removal



The head pond water levels tend to be quite shallow(less than 1.2 m on average)


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3. STUDY PROGRESS AND


TIMELINE SINCE FIRST PUBLICSESSION


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3. Study Progress and Timeline

Supplemental Field investigations to address key unknowns Extensive consultation with Ministry of Natural Resources (agency which permits and

regulates dams in Province) to discuss possible management alternatives and governingregulations

Assessment of alternatives and consultation with Technical and Stakeholder CommitteesApril 2012 Feb 2013June 2012 Oct 2012Aug 2012 Dec 2012

Develop

Alternatives

June 2013

PIC No. 1

April 2013

Consultation

with MNR

End of 2011/ 2012

Desktop

Characterization

Since First Public Session


Draft Report

PIC No. 2

Technical

Committee

Meeting No.2

Stakeholder

Committee

Meeting No.2

Assessment ofAlternatives

TechnicalCommittee

Meeting No.1

Supplemental

Field Investigations

(Pond Survey, SAR)

Stakeholder

Committee

Meeting No. 1


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4. PROBLEM AND OPPORTUNITY


STATEMENT


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4. Problem and Opportunity Statement

The Riverside Dam is over 100 years old andbeyond its design life

Structural assessments have determined thatvarious components of the dam are in poor

condition, other components have requiredemergency repair, all generally indicating that thestructure cannot be left unmanaged

Furthermore, the City of Cambridge has an


obligation to the Provincial Ministry of NaturalResources, under the Lakes and RiversImprovement Act, to implement a permanentsolution for the Riverside Dam

The Preferred Alternative must address the

Problem while balancing study area constraintsand opportunities, in order to best meet the needsof the various stakeholder groups invested in theRiverside Dam


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5. SELECTION OF ALTERNATIVES



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5. Selection of Alternatives

Seven (7) preliminary alternatives have been considered to potentially addressthe future management requirements of the Riverside Dam and local environs:

Alternative A: Do Nothing

Alternative B: Rebuild Dam In-place Alternative C: Naturalize Speed River Alternative D: Construct In-stream Rock Structures Alternative E: Lower Dam Crest


erna ve : u ne am an a ura ze pee ver Alternative G: Incremental Decommissioning of Dam

Alternatives E, F and G have been screened from further assessment as theywere not considered technically feasible nor functionally effective or would notbe permitable

Alternatives A, B, C, and D have been carried forward to be evaluated as partof the Short-listed Alternatives


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6. ASSESSMENT OF


ALTERNATIVES


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6. Assessment of Alternatives

To systematically evaluate the short-listed alternatives, a set of appropriateEvaluation Factors needed to be established

Functional

Flooding Fluvial Stability/

Sediment Transport

Natural Environment

Social

Cultural Heritage Boating Fishing Park Uses


Fish Passage Aquatic Habitat / Health Water Quality and Temperature Natural Heritage

Sediment Quality

Public Safety Economics

Capital Operations and

Maintenance Liability

Regulatory Permitability


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Alternative A Do Nothing



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Required by the Municipal Class Environmental Assessment (EA) process Represents baseline conditions November 2008 permit (MNR) for temporary emergency works states that:

City has an obligation to the Province under the Lakes and RiversImprovement Act (LRIA) to complete a Class EA (the current study) andmake an application to complete permanent works to address the dam

Alternative A Do Nothing



Only engineeredsolutions would be considered permanent works, thusAlternative A: Do Nothing is not considered feasible nor compliant withthe Provincial requirements


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Alternative B Rebuild Dam In-place



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Alternative B Rebuild Dam In-place Riverside Dam would be replaced essentially in kind, maintaining existing structurallayout/configuration aesthetics and hydraulic performance; sediment upstream of thedam would need to be removed as part of the works; a feasibility study would berequired to determine the potential for power generation




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Alternative B Rebuild Dam In-placeVisualization




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Technical & Regulatory Considerations Existing structure has no status as a dam under

Provincial policy (pre-dates), therefore a permit

for a new dam is required from Province Province requires the City to obtain flooding

rights for the increase in flood levels caused bya new dam relative to a natural river condition




this likely will require City to purchase theaffected land or acquire land rights

The Province (MNR) has indicated Rebuilding the dam does not meet itsmandate with respect to:

restoration of fisheries improving water quality supporting recovery of Species at Risk improving navigation


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Natural Environment Considerations No direct impact, but opportunities to

improve the following are not realized:

- Aquatic habitat- Fish passage- Water quality- Sediment trans ort/ ualit




Social Considerations Considered preferred solution from a

cultural heritage perspective best

opportunity to maintain existingresource in existing configuration


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Property Impacted by Alternative B Rebuild Dam In-place




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Alternative C Naturalize Speed River



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Remove Riverside Dam and with it theheadpond area

Restore river from approximately

King Street to Sulphur Creek Natural channel design

- Riffle-pool sequences


Speed River



-

- Depth varying from 1 m to 1.8 m +/- River would look and function like

Speed River up and downstream ofstudy area

Speed RiverDownstream of Dam


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Visualization



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Natural Environment Considerations

Technical/Regulatory Considerations Permit required for dam decommissioning (Provincial/MNR) MOE would require a sediment removal plan

The removal of the dam would be expected to result in an overall reduction inwater surface elevations for all design events




species, including local Species at Risk (SAR) Eliminates the negative impact (i.e. warming) of the existing headpond on water

temperature Improves water quality (dissolved oxygen)

Eliminates future liability related to contaminated sediment build-up Reinstates natural movement of sediment Returns 800 m +/- of natural river and associated riparian habitat


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Alternative C Naturalize Speed RiverSocial Environment Considerations

Highest impact on cultural heritage resources Mitigation can include:

- Protect/restore/relocate the north andsouth control structures, a portion of thegravity dam structure, and the Mill Racecontrol structure while accommodatin the



new channel- Install commemorative interpretationsignage documenting the history of theRiverside Dam and its significance to thePreston community

Reduction in nuisance flooding in RiversidePark and related park closures


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Alternative D Construct In-Stream


Rock Structures

6 A f Al i


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Remove Riverside Dam and headpond Construct 4 +/- rocky ramps from

downstream of King Street and

upstream through headpond Rocky ramps would:

- Collectively generate the height of

Alternative D Construct In-Stream Rock Structures



.

- Span the width of the existingheadpond (+/-)

- Cause localized ponding areasupstream

- Would have a cascade effect ondownslope (4%)

6 A t f Alt ti


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Alternative D Construct In-Stream Rock Structures Under low flow conditions, the top of

the rocky ramps will be visible

extending from the banks towards the

centre of the ponded area The river would generally be

navigable through Riverside Park

when the similar reaches of the



Speed River are navigable (this

depends on flows and type of boat) Large storm events may cause minor

shifting in the ramps;

The river will be calmer upstream of

the rocky ramps, especially towardsthe banks, and faster in the centre, as

it flows over the ramps

6 A t f Alt ti


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6 A t f Alt ti


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Alternative D Construct In-Stream Rock StructuresVisualization



6 Assessment of Alternatives


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Technical/Regulatory Considerations Permit required for dam decommissioning but does not require approval as

a dam by the Province (requires approval as channelization)

The removal of the dam would be expected to result in some reduction inwater surface elevations for all design events MOE would require a sediment removal plan




Provides migratory access for fish and aquatic species, including localSpecies at Risk (SAR)

Improves water quality (dissolved oxygen)

Social Environment Considerations

Level of impact on cultural heritage resources would be the same asAlternative C

Mitigation measures would be similar to Alternative C

6 Assessment of Alternatives


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AssessmentCategory Assessment Factor Alternative A:Do Nothing Alternative B:Rebuild Dam

Alternative C:

Naturalize SpeedRiver

Alternative D: In-

Stream RockStructures

Functional(Physical)Environment

Flooding

Fluvial Stability / Sediment Transport

NaturalEnvironment

Fish Passage

Aquatic Habitat / Health

Water Quality and Temperature

Natural Heritage

Sediment Quality



SocialEnvironment

Cultural Heritage

Boating

Fishing

Park Uses

Public Safety

Economic Capital

Operations and Maintenance

Liability

Regulatory Permitability

Positive Positive Neutral Neutral Negative Neutral Negative Does not meet Regulatory Requirements Meets Regulatory Requirements


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7. LEGISLATIVE AND


REGULATORY REQUIREMENTS

7 Legislative and Regulatory Requirements


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Relevant Legislation:- Lakes & Rivers Improvement Act- Public Lands Act- Navigability Act

- Fisheries Act- Conservation Authorities Act- Cultural Heritage Act- Endangered Species Act / Species at Risk Act

7. Legislative and Regulatory Requirements


- Environmental Protection Ac

- Water Resources Act Administered by several regional, Provincial and Federal agencies:

- Grand River Conservation Authority- Ministry of Natural Resources

- Ministry of the Environment- Department of Fisheries & Oceans- Transport Canada- Ministry of Tourism, Culture & Sport

7 Legislative and Regulatory Requirements


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Permitability of Short-Listed Alternatives Under Relevant Provincial/Federal Policy

Legislative PolicyAlternative A:

Do Nothing

Alternative B:

Rebuild Dam

Alternative C:

Naturalize Speed River

Alternative D:

In-Stream Rock

Structures

Lakes & Rivers Improvement Act

Public Lands Act

Navigable Waters Protection Act

Fisheries Act

7. Legislative and Regulatory Requirements


Conservation Authorities Act

Ontario Heritage Act

Species at Risk Act

Environmental Protection Act

Water Resources Act

Less Preferred Does not meet Regulatory Requirements Meets Regulatory Requirements


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8. COST AND LIABILITY


8 Costs and Liability


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Preliminary Cost EstimateEstimated Life Cycle Cost for Short-Listed Alternatives ($)Alternative Capital Land Replacement Maintenance Total Life Cycle

Alternative A:

Do Nothing0 0 0 0 0

Alternative B:

Rebuild Dam

In-place

5,805,000 8,525,000+ 1,205,000 802,000 16,337,000

8. Costs and Liability


Alternative C:

Naturalize SpeedRiver

4,953,000 0 0 275,000 5,228,000

Alternative D:

In-Stream Rock

Structures

6,715,000 0 0 190,000 6,905,000

8 Costs and Liability


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Potential Liability of Short Listed Alternatives City accepts liability for the infrastructure it builds Liability results from normal operation of infrastructure and potential failure scenarios The larger the infrastructure, the greater the potential damage Potential liability:

- Damage to project infrastructure itself

- Damage to downstream infrastructure (CPR bridge), buildings, environment- Risk to Life

8. Costs and Liability

Estimated Potential Liability for Short-Listed Alternatives

*


* 1 = highest relative risk and 4 = least relative risk

Alternative A: Do Nothing 7,681,000 1

Alternative B: Rebuild Dam In-place 13,486,000 2

Alternative C: Naturalize Speed River Minimal 4 (Typical river)

Alternative D: In-Stream Rock Structures 750,000 3


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9. FREQUENTLY ASKED


QUESTIONS (FAQS)

9. Frequently Asked Questions (FAQs)


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Q1. How long before the dam fails?

A1. Predicting when a structure will fail is very difficult and depends on

several variables. Instead we rely on indicators like the structuralcondition of the dam to indicate the potential to fail. Investigations have

determined that portions of the dam are in poor condition indicating the


.

dam will continue to deteriorate without mitigation.



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Q2. Why cant the current dam be just repaired? Why would it have tobe a full replacement?

A2. Since the existing Riverside Dam does not have status with the Province

under the Lakes and Rivers Improvement Act (it pre-dates the Act), anyrepair or modification to the dam would trigger the necessity for thepermit for a new dam and the structure would be required to meet the


curren es gn requ remen s o e rov nce. e ex s ng am, a over

100 years old, was not designed or constructed to current standards andwould therefore need to be fully rebuilt.



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Q3. When will the Preferred Alternative be selected?

A3. The Preferred Alternative will be selected once all comments have been

received from the public and regulatory agencies. All comments areexpected to be received by the beginning of July 2013. It is anticipated

that the final report will be filed and available for public comment in


.



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9 eque t y s ed Quest o s ( Qs)

Q4. What will be the impact to Sulphur Creek if the dam is removed?Will water in the creek be maintained?

A4. The flow into Sulpher Creek would need to be maintained by providing

riffles or other structures in the Speed River to maintain water levelshigh enough to divert flows into Sulpher Creek. Alternatively, or incombination, the inlet to Sulphur Creek could be altered, thereby


mprov ng t e a ty to contro n ow to t e u p ur ree .



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q y Q ( Q )

Q5. Will removing the dam stop the flooding in the park (i.e. the ball

diamonds)?

A5. Removing the dam will lower flood elevations and reduce the frequency offlooding in the park, however flooding will not be eliminated.




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q y ( )

Q6. Will the removal of the dam affect the flooding of propertiesdownstream of the current dam location?

A6. Removing the dam would in fact reduce the risk of flooding associated

with a dam failure. Removing the dam would not change the extent ofthe existing downstream Regulatory floodplain or floodplains associatedwith other storm events.




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q y ( )

Q7. Will any of the alternatives for the dam harm any of the SAR identified?Will removal of the dam help invasive species invade the upper reachesof the Speed River ?

A7. None of the alternatives will harm the identified SAR, the alternatives toremove the dam will serve to benefit these SAR. Invasive aquatic speciesknown in the Grand River Watershed include the Round Goby, Sea Lamprey,


e ra usse , s an rass arp, an t e usty ray s an none o t ese

species will be affected by this project. Invasive species have not beenidentified as a threat by our team, MNR or GRCA.



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q y ( )

Q8. What will the sediment management plan entail? Why the high cost? Wherewould the sediment be taken to?

A8. The form of the sediment management plan would be dependent on the Preferred

Alternative which has yet to be determined by this study. It will also be dependent onthe volume and quality of sediment to be managed, which will be determined in detailat the next stage of assessment, and finally on the opportunity to use the sedimentelsewhere. The sediment management plan could include one or a combination of the


o ow ng: management on-s te us ng t e se ment or ot er purposes n vers e

Park), disposal at another site in need of fill, or disposal in landfill.

The cost represents a worst case scenario whereby all of the accumulated sedimenthas been assumed to be contaminated, could not be managed onsite in a safemanner, and would require landfilling as contaminated waste. The cost is high

because of the following: the volume of sediment is significant, the cost to remove itfrom a sensitive watercourse is high, the sediment will be wet and require dewatering,the cost to transport it is high, and the tipping fees to landfill it are high.



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Q9. How will the options affect canoeing?

A9. Alternative B: Rebuild Riverside Dam would maintain flat water boatingopportunities in the headpond as per existing conditions. Navigation

would be impeded by the dam.Alternative C: Naturalize Speed River would provide river (movingwater) boating conditions. Depths would be similar to Speed River up


.

would generally be navigable through reach adjacent to Riverside Parkwhen similar reaches of the Speed River are navigable (this depends onflows and type of boat).Alternative D: In-stream Rock Structures would provide a mix of flatwater and moving water conditions. The extent of flat water conditionswould be smaller than the existing headpond. The river would generallybe navigable through Riverside Park when the similar reaches of theSpeed River are navigable (this depends on flows and type of boat).



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Q10. Who will be covering the cost of the proposed work?

A10. The City of Cambridge will be responsible for the cost of designing and

constructing the preferred alternative, once selected. At this time, the

City has allocated $5.0M as part of the Capital Budget that is intendedfor the preferred alternative. Various cost sharing opportunities will be

investigated during the detail design phase.




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Q11. How does the cost of rebuilding the Riverside Dam compare toother local dams?

A11. The GRCA has recently completed a similar study for the Drimmie Dam

in Elora. The cost of rebuilding the Drimmie Dam was estimated at$1.2 million (2010). This is comparable to the estimated cost forRiverside Dam which is $2.1 million (excluding sediment


partially accounts for the difference in cost. Other factors includegeotechnical conditions, site access, site dewatering, etc.

Note: It should be clearly understood that the full Life Cycle cost of the DamRebuild alternative is estimated at $16.3M which includes capital, land,

maintenance and long term obligations to rebuild and removesediment (this excludes liability estimates discussed earlier)



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Q12. When will construction start?

A12. Construction is anticipated to begin at the earliest in 2015. The City will

first have to file the Class EA and then complete detail design and

acquire all necessary approvals before construction can begin.



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10. NEXT STEPS


10. Next Steps/Schedule


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Next Steps

Finalize assessment of short-listed alternatives

based on comments received from regulatory

agencies and the public

Establish Preferred Alternative Document assessment of preliminary

alternatives and Preferred Alternative in Project


Establish Budget for Capital works Initiate detail design and approvals of Preferred

Alternative

Schedule

Receive comments by July 5, 2013 Finalize and File Project File in September 2013

Closing Remarks


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Public Consultation is essential to the EA Study Process Public reaction has been substantial, passionate and split

We need and appreciate all comments

Please share your passion....respectfully

Work Stations provided for your comfort Ask questions, discover what we have learned

Look, point, draw, write, chat, share...


Help shape the best solutionThank You


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Breakout to Work Stations


Work Stations


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Please join our Consultant Team at one of the three Work Stations you see inthis room.

Each Work Station is the same and includes:

Drawings that illustrate each of the preliminary alternatives

City Staff and Consultant Team Members to facilitate a discussion,answer questions and take notes


Comment sheets are also available to fill out now or to take home and submit

later.

We are here tonight to hear from you

and answer your questions.

Public Information Centre Layout


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riverside dam presentation june 18, 2013 @ knights of columbus hall

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