Water Power and Dam Construction. Issue April 2009

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32 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

INSPECTION

pany also tends to dive into damaged areas frequently that, though

manageable with extensive safety protocols, are certainly much less

dangerous after a detailed initial inspection with the LBV200.

The modern mini ROV such as the LBV 200 allows field teams

to access areas that divers cannot inspect, gather information (such

as heading) that is difficult to impossible for a diver to effectively

gather, and occupy areas and situations (depth, water temperatures

and low visibility) that are too hazardous for divers.

ROVs such as the LBV200L can be effectively launched and man-

aged by one person if need be, immediately reducing labour cost.

The size and weight of the system is considerably less than that of

previous systems, reducing transportation and deployment costs.

The particular environment that was discovered in the gate system

was highly dangerous. Initial ROV dives discovered that the gate

had sheared its downstream guides completely away due to failure

of the concrete pier structure, and was precariously balanced against

the remaining pier wall and scroll case downstream and off angle of

its intended position.

Large masses of concrete that originally made up the guide pier

were hanging in broken pieces from the mangled and twisted H-

beam that served as the sealing surface of the guide.

The pieces of concrete were only held in place by the anchors that

originally attac h ed the H-beam to the pier. These were obviously

severely stressed and unstable. This area was approximately 12m

off of the concrete bottom, limiting the area that a diver could safely

search. Inspection of this damage by a diver would have required

securing the upper portions of the gate to the remaining (though

now questionable) pier sections and slowly working down the face

of the gate as the diver progressed to greater depths. The upper por-

tions of the separated concrete and H-beam would have had to be

either secured or cut away and allowed to drop to the bottom, con-

taminating the scroll case further with debris. Simply engineering

and implementing the safety plan would have required days of highly

dangerous work. However, the ROV with onboard navigation was

able to penetrate the gate area and inspect the damage from the top

to the bottom without any risk to a diver.

The ROV was deployed under the gate and into the area of hang-

ing concrete and gathered info rmation that drove the dive safety

plan forward, with a much better understanding of the complexities

of the failure and the resultant situation. Thus, the ROV increased

the safety of the job in two ways:

• Limiting the exposure of the diver to an unknown and possibly

dangerous situation.

• Gathering detailed and reliable information that would enable the

diver to quickly and safely transverse the damaged gate to provide

more detailed information for the purpose of removing the gate.

The LBV200L was able to access areas that no responsible safety

plan would have allowed a diver to occup y. The dive safety plan

therefore could be engineered as a complete system from the begin-

ning, rather than a ‘secure a little and go’ approach.

DVANCED TECHNOLOGY

The increase in quality due to the use of the LB V200L is multi

faceted as well. The LBV200L has advanced onboard technology

N mid 2008, a large subsurface explosion was heard at a hydro

station in the US. The violence of the explosion and its concur-

rence with the cycling of the wicket and head gates caused the

owners grave concern, with many unanswered questions regard-

ing the nature of the event and possible damage that it had caused.

An immediate surface level inspection of the facility offered no

visual indications as to what had happened. The owner quick ly

determined that an emergency underwater inspection was critical to

protect power and water supplies.

Glenn Underwater Services (GUS) was selected to quickly assess

the situation and deliver a clear report and action plan. The hydro

project owner t asked GU S personnel with performing a detailed

underwater inspection to ascertain what had occurred during the

gate cycle. There were safety concerns connected to sending a diver

into an unknown situation within a large gate system, and so the

company deployed its LBV200L mini ROV prior to any diver enter-

ing the water.

The gate in question was approximately 6m wide by 15m high

and operated within a traditional guide system. The bottom seal was

located approximately 28m below the surface of the water. GUS was

able to almost immediately deploy the LBV200 once on site due to

the minimalist setup process and site preparation required. Th e

deployment cycle alone saved a full day that otherwise would have

been spent mobilising a dive team and setting up a dive station. Once

in the water the LBV200 began what became a lengthy and highly

technical inspection of what was soon discovered to be a gate col-

lapse resulting from a guide failure.

UBSTANTIAL DAMAGE

Glenn Underwate r Services has been using ROVs for ma n y years

and is very familiar with the benefits of their application. More

advanced camera systems, navigation and imaging sonars, position

systems and more advanced flight controls with the LBV200 h as

enabled the company to expand its use of ROVs to a wider range of

applications. The main advantages are now at hydro facilities.

Diving environments are quite often cramped, deep, with limited

visibility and a high potential for differential pressures. The com-

Technological advances have made ROVs even greater value in hydro power inspections.

Caleb Adams and Richard L Glenn from Glenn Underwater Services highlight the

advantage of deploying ROVS into situations deemed to be too dangerous for divers

The LBV200 ROV

Mini ROV plays major role

INSPECTION

contained in a small package that makes gathering the critical infor-

mation required of such an inspection far easier and more succinct.

Due to the destruction of the original guide system and gate, many

of the common visual reference points used to position a diver were

absent. A diver inspecting such an area would, for example, make

numerous references to the guide itself to make measurements. He

would also use the gate and guide to hold a steady position in the

water. The limited visibility present (0.9m) would make longer mea-

surements difficult and unreliable.

The use of the Tritech Micron Sonar system aboard the

LBV200L allowed topside personnel to maintain positional aware-

ness by reference to the entire pier structure. The team was able to

ensure that a complete inspection had been performed and that

there were no surprises hidden just out of the range of a diver’s vis-

ibility. Equally, the auto heading and auto depth functions allowed

for lo nger inspection of critical areas. A diver would have, for

instance, been required to hold onto material that was structural-

ly questionable, or simply fin in place in an attempt to get a steady,

long shot in any one area.

The LBV200L could be ‘parked’ at that same area without any

need for additional support and be kept there until all the topside

personnel were satisfied that the appropriate amount of informa-

tion had been gathered.

The benefits of the LBV200L on this project were its lateral

thruster, allowing the operator to m ove sideways along the area

of inspection while kee p in g the sens o r s on targe t . In additi on , on-

the-fly ten-step thruster gain adjustments and a 32- step precision

joystick enabled the operator to precisely tune power output to

the minimum required to over come currents while providing a

smooth, stable platform for optimising the qual ity of the video

and se nsor data.

OST REDUCTION

The cost reduction and safety potential of the mini ROV is perhaps

the main reason that it has entered into the market so effectively.

The LBV200’s combination of cost, advanced onboard technology,

speed, stability, accuracy, risk reduction and the ability to deploy the

system without any other required assets make it an invaluable tool

with obvious price benefits.

In the case of the gate collapse the cost benefits started to accrue

immediately following initial contact by the owner. The inspection

was conducted and the gate removed without any incidents to the

owner or contract personnel.

Caleb Adams and Richard L Glenn, Glenn Underwater

Services, 6401 Carmel Rd Suite 209,

Charlotte NC, 28226, US. Email:

rickglenn@glenndiving.com

WWW.WATERPOWERMAGAZINE.COM APRIL 2009 33

The gate did substantial damage to the concrete base of the scroll case

IWP& DC

Below: Rov inspecting an intake guide

Poor visibility (as above) was overcome with the Tritech Micron Sonar

Above and below: Images from the ROV show the substantial damage

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INSPECTION

WWW.WATERPOWERMAGAZINE.COM APRIL 2009 35

IVING AT

NDERWATER

ENTRE

The Underwater Centre’s diving school has over 30 years experience

in providing divers with the legislational and vocational qualifica-

tions required by the diving industry. As far as legisl ation is con-

cerned, The Underwater Centre trains divers who, once they have

successfully completed a course, are qualified under UK Health and

Safety Executive (HSE) certification. The HSE diving ‘ticket’ is inter-

nationally recognised and is ge nerally viewed as the benchmark,

allowing a diver to work almost anywhere in the world.

There are four component parts of the HSE’s div er legislation.

Numbered parts I-IV cover the key skills of scuba diving, surface

supplied diving, surface supplied top up diving (known colloquial-

ly as wet bell) and closed bell diving (also known as saturation and

mixed gas). Possession of these certificates allows you to work legal-

ly as a diver. However, like most jobs, you don’t get paid for travel-

ling to work, which, when you get to the nub of it, is all the diving

qualifications are. Instead, you get paid for working.

This is where the additional training in the var ious vocational

skills comes in . Student s on The Underwater Centre’s 13-week

course will learn how to weld and burn underwater, use power tools

and pneumatic equipment safely an d ge nerally le arn most skills

required for carrying out underwater inspections. The school trains

around 150 new commerc ial divers each year as well as training

HE Underwater Centre in Scotland was set up in the early

1970s by the UK government to enable divers to be trained

in the skills required to service the booming North Sea oil

and civil engineering diving industries safely. They chose

Fort William, a small Scottish town at the head of Loch Linnhe, as

the location for their school. With a sheltered inland location, cou-

pled with wate r depths of 5 0m withi n a stone’s throw and 150m

within a mile or so, The Underwater Centre is blessed with an

impressive subsea geography. The combination of a sheltered, sea-

water site wh ich pro vides direct access to a wide r ange of water

depths makes it an ideal location, not just for learning to dive, but

for ROV training and, increasingly, technology trialling. An extra-

ordinary array of wrecks, vehicles, equipment and structures means

that there are numerous and varied training and equipment trialling

opportunities all year round.

The Underwater Centre has a sister school of the same name at

Beauty Point in Tasmania, Aust ralia. B oth scho ols’ cou rses are

designed to provide suitable training so that students meet the inter-

nationally recognised standards for scuba, surface supplied, wet bell

and closed bell diving. Vocational skills such as non destructive test-

ing, subsea welding and tools usage are provided by both schools as

part of their training packages. As well as the varied diving courses,

The Underwater Centre also offers courses for prospective dive

supervisors and assistant life support technicians.

Commercial inspection divers are required

to undertake a number of physical tasks.

These include manhandling debris from

sluices and fish ladders to welding, burning

or concreting. Once you add low visibility,

low temperatures and the possibility of

working in confined spaces, it is easy to

understand why such a specialist job

requires thorough training. Dougie

Ormiston from The Underwater Centre in

Scotland gives more details

In at the

deep end

The centre offers ROV training and technology trialling

The centre offers courses on underwater welding and burning

36 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

INSPECTION

ter inspect ion divers. Qualification under the CSWIP umbrella

requires students to complete a preparatory course which includes

classroom work as well as practical, underwater inspections. Once

they are assesse d as being of sufficient pr oficiency, they will be

allowed to take th e formal examination. The Underwater Centre

runs preparatory courses for the CSWIP qualifications which, once

successfully completed, prepare students for the formal exam.

The growing demand for qualified inspection personnel, and the

increased employment and earning potential this offers divers and

ROV pilots, has meant that the waiting list for exams has increased

dramatically in recent years. This shortfall in manpower has raised

the question of whether it is better, and easier, to take skilled

inspectors and teach them to dive as an alternative t o training

divers to be inspectors.

Whilst there may be some credence to the idea that training some-

one to dive is, theoretically, easier than training someone to inspect,

there are far more divers capable of training successfully as inspec-

tors than there are i nspectors who will be able to train as divers.

Even then, once an inspector has got their diving certification, they’ll

still have to complete a 3.1U preparatory course and pass the exam.

As well as underwater inspection, commercial divers are required

to undertake a number of much more physical tasks as a result of

their efforts. These tasks can include manhandling debris from

sluices and fish ladders to welding, burning or concreting. Once you

add low visibilit y, cold and the possibility of working in very

enclosed spaces, quite why commercial diving is such a specialist job

is easy to understand. This makes the idea of traini ng specialist

inspection divers less tenable.

As the requirement for skilled subsea inspection personnel grows,

partly due to the inspection requirement of aging oil and gas facilities

and partly due to the increasing numbers of maritime energy genera-

tion projects such as wind farms and wave and tidal systems, the like-

lihood is that more and more divers and ROV pilots who are qualified

as inspectors will move to these more lucrative sectors of the indus-

try. In the long term, it is unclear where this is likely to leave tradi-

tional civils works, like dam and harbour inspections.

Dougie M Ormiston, The Underwater Centre, Scotland

Email: douglas@theunderwatercentre.co.uk

For more details log on to

www.theunderwatercentre.co.uk

approximately the same number of experienced commercial divers

in closed bell diving and underwater inspection.

ROV

The development of ROV systems to support oil and gas exploration

of ever-deeper regions of the ocean floor has resulted in an unprece-

dented rise in demand for ROV pilot technicians. The Underwater

Centre’s team of experienced ROV instructors train students from

all over the world in every aspect of not only how to fly an ROV,

but to also ensure that it is in a suitable condition to fly. All of the

hydraulics and electronics elements required to keep an ROV in the

water are included in the course material.

The International Marine Contractors Association (IMCA) has

approved guidelines for ROV courses, and all of The Underwater

Centre’s ROV courses meet the IMCA guidelines. The industry

standing of The Underwater Centre as a benchmark for ROV train-

ing can be measured in the number of top level ROV operators who

are seeking to use Fort William’s exceptional dive site, pier complex,

purpose built training rooms, ROV work shops and team of spe-

cialist tutors to deliver training to their new recruits. A purpose built

simulation, along with a variety o f subsea structures, submerged

vehicles and wrecks means that even the most capable of pilots will

be challenged when flying one of The Underwater Centre’s ROVs.

Over 700 students have trained here over the past 11 years, includ-

ing teams from the National Oceanography Centre, the Portuguese

Maritime Inspectorate and pilots from Russia’s Pod Vod Services.

NDERWATER INSPECTION

As the subsea and civils diving industry has evol ved, so have the

requirements upon divers and ROV pilots. What used to be a pre-

dominantly construction based job is becoming ever more focussed

on inspection as part of planned maintenance regimes. CSWIP, the

certific ation body for underwater inspection, oversees a series of

qualifications for non destructive testing underwater.

Inspection falls into two broad categories; routine inspection as

part of a planned maintenance programme and surveying to assess

a site prior t o unde rtaking constructi on or remed ial work. The

diving qualifications, 3.1U and 3.2U, teach divers how to accurate-

ly inspect and record their findings. The 3.3U certificate is the ROV

pilot equivalent.

There is, in addition to the ‘wet’ qualifications, a course within

the CSWIP curriculum relating to topside supervision of underwa-

A diver’s role is becoming increasing focused on inspection as part of planned maintenance regimes

IWP& DC

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38 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

PUMPED STORAGE

TAH

The state of Utah has never been synonymous with green energy.

Utah’s energy production has always been heavily based on coal

mining and coal-fired power plants. In 2006, 90% of Utah’s elec-

tricity came from coal. While base load demand has been growing

steadily at 2.6% annually, peak power demand has increased 5.4%

annually. Although coal is locally available, inexpensive and reliable,

it does not provide for daily fluctuations in power demands. Natural

gas-fired plants have been added to meet growing peak demand, but

this solution adds to the output of carbon dioxi de emission s.

Additionally, these costly gas plants built to respond to infrequent

spikes in demand lie dormant for most of the year.

The benefits of pumped storage hydro power in Utah would be

numerous. Utah does not currently use pumped storage but relies on

peaking power plants to respond to peak power demand. Pumped

storage will be a key feature in the transition away from fossil fuel-

fired power plants by providing a method to store intermittent solar

and wind power as these resources are developed in the state.

ROJECT LOCATION

The North Eden project will be located in Rich County just east of

Bear Lake. This is a popular recreation destination shared by south-

eastern Idaho and northwestern Utah. The upper reservoir will be

built on the eastern flank of Black Mountain; the lower will be locat-

ed in North Eden Canyon. The location of the project is shown in

Figure 1.

At this point in the FERC application process, all engineering data

is conceptual and preliminary. Detailed enginee ring will be com-

pleted prior to the submission of the final licence application. Figure

2 is a conceptual drawing of project features. This pumped storage

project is expected to yield a total of 700MW daily. When the upper

reservoir is at full pool the maximum head will be 283m, and the

minimum will be 227m. The maximum flow rate from the upper

reservoir is estimated at 373m

/sec.

The upp er dam, referred to as Black Mountain dam, wil l be a

zoned embankment type with a clay core flanked by shell material

sourced from outcrops in the project area. The dam will be approx-

imately 31m high with an emergency spillway running eastward to

North Eden Canyon. The spillway will be 9m at its base, with 2:1

side slopes and a longitudinal slope of 5%. The maximum capacity

of the spillway will be approximately 75m

/sec. The Black Mountain

dam will impound a reservoir with a surface area of 132 acres (53ha)

at maximum water surface elevation of 2148m asl. Gross storage

capacity will be 10,962 acre-feet (13.5Mm

) and the usable storage

capacity will be 10,510 acre-feet (13Mm

). The floor and side slopes

of the reservoir will have a multi-layer construction consisting of a

0.6m clay layer overlain with a non-reinforced EPDM geomem-

brane, which will then be covered by 0.6m of soil. The intake will

consist of a glory bowl with a valve to isolate the penstock.

UMPED storage is poised to be a major player in the

renewable energy field. Wind ge nerati on conti nues to

develop, while renewable portfolio standard mandates

loom like clouds over solar panels. It is time to expand

green energy resources.

The last time a new pumped storage project was built in the US

was over 20 years ago. It’s an old and proven technology but one

that has fallen out of favour here. There have been some economic

pitfalls, some environmental blunders, and some failures. But today

pumped storage is being recognised as a proven and environmen-

tally feasible way to provide the benefits of energy storage, grid sta-

bilisation, and the harnessing of intermittent renewable sources.

Symbiotics, a Utah-based company, is in the preliminary stages of

the North Eden pumped storage hydroelectric project, which will

provide energy shaping and grid stabilisation for Utah’s coal-reliant

energy portfolio.

Making the most of

pumped storage

It’s been 20 years since a pumped storage plant was built in the US. However, the

development of the North Eden project is set to change this. Rachel Wright from

Symbiotics explains how the scheme will help to reshape Utah’s energy portfolio.

Figure 1: Project location

WWW.WATERPOWERMAGAZINE.COM APRIL 2009 39

PUMPED STORAGE

advantages of this system are that once the initial fill has occurred,

the only water needed will be a small amount to offset annual evap-

oration from the reservoirs. The precipitation and evaporation bal-

ance will result in an annual water loss of approximately 0.2m over

the total surface area of both reservoirs.

It is currently proposed that approximately 14km of 230kV trans-

mission line will be constructed to connect the project to an exist-

ing 230kV PacifiCorp transmission line located east of the project

site. The p reliminary plan includes construction of one switch-

yard/substation near the upper dam site, with the potential need for

a second. To minimise possible visual impacts, this substation will

be located on the eastern side of the upper reservoir. A second sub-

station may be needed for interconnection.

he North Eden project will be located near a newly proposed

transmission l ine which may be a viable option for interconnec-

tion. The benefits of the proximal location to transmission struc-

tures are that it will allow the utilities or line owners to stabilise

the energy efficiently by adding, reducing or pulling load off the

system. The project will help utilise the capacity of large trans-

mission lines more effectively and stabilise Wes tern Electricity

Coordinati ng Council (WECC) infrastructure. The WECC is the

energy council that distributes power throughout the western US

and British Columbia, Canada.

ROJECT OPERATION

At the initiation of each daily cycle, 10,510 acre-feet (12.93Mm

)of

water will be pumped from the lower reservoir to the upper reser-

voir. Later in the cycle this process will be reversed, with the same

The lower reservoir and dam will be located one mile from the

mouth of North Eden Canyon on North Eden Creek. The lower dam

will be approximately 52m high, built at a base elevation of 1846m

asl in a similar manner to the Black Mountain dam with an imper-

vious clay core surrounded by more pervious outer layers. There will

be an emergency spillway for the lower reservoir with a maximum

apacity of 10,000ft

/sec (283m

/sec). The spillway will extend to

the abutment of the dam in North Eden Canyon. It will be 18m wide

at its base, with 2:1 side slopes and a longitudinal slope of 5%.

The lower reservoir will have a surface area of 250 acres (101ha)

at maximum water surface elevation of 1891m asl. The gross stor-

age capacity will be 13,761 acre-feet (17Mm

) and the usable capac-

ity will be 11,932 acre-feet (14.7Mm

). Approximately 1000 acre-feet

(

1.2Mm

)

will be dead storage, as the base of the dam will be below

the intake/outtake structure. The side slopes and base will be similar

to the upper reservoir with a multi-layer composition of clay, EPDM

geomembrane and soil. Water discharged from the turbines will enter

a stilling basin located approximately 24m below the minimum pool

elevation. Placing the intake/outlet structure at this location should

alleviate the potential for cavitation during operation.

A 792m long, 9m diameter tunnel with a 32% longitudinal slope

will connect the two reservoirs. Transitional penstocks will connect

the main tunnel to the pump turbine units. The powerhouse will

contain as many as seven variable speed pump-turbines. It will be

located on the south side of the lower reservoir and will house the

turbine units and a control room.

North Eden Creek will be the primary source of water for the ini-

tial fill of the lower reservoir. Water rights will need to be secured,

both for the initial fill and annual evaporation maintenance. The

Conceptual drawing of the project features

40 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

PUMPED STORAGE

mitigation options are being explored.

One proposed option is that Symbiotics will rehabilitate 2km of

North Eden Creek between the project and Bear Lake. This would

involve fencing off riparian habitat from livestock, restoring stream

form and function a nd r eintro ducing Bonneville cutt hroat trout.

Another possibility is the restoration of connectivity to Bear Lake

by means of a fish ladder. This would allow natural recruitment of

Bonneville cutthroat in North Eden Creek from Bear Lake.

Construction of the project will permanently displace 400 acres

(162ha) of shrub-steppe habitat and alter North Eden Canyon’s value

as a wildlife corridor on the Bear river plateau. Some recreational

hunting takes place in the area for deer, partridge and sage grouse

and this could be affected by the project. Before construction com-

ences, a variety of surveys will take place to document wildlife use

of the area and delineate habitat for sensitive species. This will aid

habitat rehabilitation and mitigation efforts. Some species of concern

that could occur in the project area are greater sage-grouse, pygmy

rabbit, loggerhead shrike, burrowing owl, willow flycatcher and

western toad. Sensitive plant species surveys and noxious weed sur-

veys will inform construction efforts and revegetation efforts fol-

lowing construction.

ISUAL RESOURCES

It is expected that project features will not be visible from Bear Lake,

a popular recreation destination. A study has been proposed to doc-

ument the current character of the local landscape and to investigate

and ensure that project features will not be visible from viewpoints

within the greater Bear Lake area. In addition, project features will

be designed to blend in with their natural surroundings.

The National Register of Historical Places and the state of Utah

do not identify any culturally or historically significant sites within

the project area. However, all ground disturbing activities will be

preceded by a cultural resources survey to prevent displacement of

valuable cultural resources.

ROJECT PROGRESS

The North Eden project is currently in the licensing stage of project

development. Symbiotics was issued a preliminary permit from FERC

on 24 December 2008. The pre-application document, which pre-

sents the preliminary plan and environmental impacts of the pro-

posed project, was submitted on 22 January 2009, along with a

request for the use of the traditional licensing process (TLP).

Symbiotics is currently waiting for FERC to approve their request

to use the TLP and will be receiving a response soon. A public scop-

ing meet i ng is expected to take place in May and, following this,

Symbiotics will begi n the first year of environmenta l studies.

Submittal of a final licence a pplication co uld occ ur as early as

December 2010, with construction beginning in 2013.

Progress on this project may be t racked on the FERC website

(www.ferc.gov) in the E-library under the North Eden Pumped

Storage Hydroelectric Project, Docket No. P-13249.

Rachel Wright is a technical writer at Symbiotics in

Portland, Oregon, US. Email:

rachel.wright@symbioticsenergy.com

amount of water being discharged from the upper reservoir to run

through the turbines and generate power. The result will be a total

fluctuation of 20m in the lower reservoir and 29m in the upper reser-

voir. The project is expected to operate in pump mode for 14 hours

a day and turbine generation mode eight hours a day, with two hours

for reserve in the case of emergencies. The 700MW capacity will be

available daily, for up to 10 hours a day. The project is expected to

have 75-76% wire to wire efficiency. Table 1 contains the average

production in kWh monthly and annually.

NVIRONMENTAL CONCERNS

Symbiotics’ biologists and engineers seek to develop a project that

has the least impact possible on the environment. However, the cre-

ation of two reservoirs will involve the inundation and subsequent

displacement of terrestrial and riparian habitat. Symbiotics has deter-

mined the potential impacts and concerns associated with all aspects

of the project in its preliminary-application document (PAD) based

on existing data. Studies will be required to determine the environ-

mental impacts and mitigation needs of the project. In the next step

of the licensing process, Symbiotics will supply a study plan that will

be reviewed by the FERC, resource agencies and the public. This will

inform future study and mitigation efforts.

The North Eden project will inundate 5km of North Eden Creek

and therefore cannot be considered a closed loop system. In addi-

tion, three of these five kil ometer s ar e considered ‘high quality

waters’ and some riverine fish habita t w ill be permanently lost.

However, North Eden Creek currently loses all connectivity to Bear

Lake in the summer due to irrigation water rights that use all exist-

ing flows. The existing storage right in the system for water rights

holders is 400 acre-feet (493,376m

), with an additional 0.11m

/sec

diversion rights for the stream. Symbiotics will maintain all down-

stream irrigation and municip al water rights. The possibility of

improving and maintaining the quality of North Eden Creek below

the project is being explored as a mitigation option.

The project will require a substantial amount of earthmoving,

including the excavation of the reservoirs, the clearing of dam foun-

dations to bedrock, excavation and placement of dam fill materials

and excavation for penstocks, spillways and the powerhouse. Roads

and road upgrades have been proposed to allow access to project

features. All of these activities have the potential to discharge sedi-

ment into nearby Bear Lak e. In order to receive the Section 401

water quality certification, Symbiotics will develop a soil erosion

control plan that will address all concerns associated with project

construction.

ISHERIES

WILDLIFE AND BOTANICAL RESOURCES

Some of this riverine habitat will be permanently lost due to the pro-

ject. The Bonneville cutthroat trout (Oncorhynchus clarki utah), a

native species that occurs in North Eden Creek, is considered a core

population with a conservation management designation. There are

some concerns about impacts upon the habitat of this species and

IWP& DC

Symbiotics’ hydro portfolio

Symbiotics has been developing low impact hydroelectric projects since

2001. The company was formed by merging the resources and expertise of

Ecosystems Research Institute and Northwest Power Services. This merger

combined over 30 years of experience in selecting, permitting, constructing

and operating hydroelectric facilities. The company currently has five new

run-of-river hydroelectric projects with FERC licences, two of which are under

construction; three run-of-river projects in operation; and FERC preliminar y

permits for 39 new run-of-river hydroelectric projects and 11 closed loop

pumped storage projects.

Table 1: Average monthly energy

production for the proposed

North Eden project

Month Production (kWh) Month Production (kWh)

January 172,298,000 July 172,298,000

ebruary 153,749,000 August 172,298,000

March 172,298,000 September 166,740,000

pril 166,740,000 October 172,298,000

ay 172,298,000 November 166,740,000

June 166,740,000 December 172,298,000

NNUAL = 2,026,795,000