Sha Dadx Habitat Restoration Project The Good, The Bad, & The Costly

Megan Hilgart, NOAAJason Lehto, NOAA

Larger Project Context

The project was constructed with funds from the Commencement Bay Natural Resource Damage Assessment.

Trustees (NOAA, USFWS, Puyallup Tribe, Muckleshoot Tribe and WA State Dept of Ecology) performed injury assessment at the Superfund site.

Trustees received funds through settlements with the parties responsible for the contamination to perform compensatory restoration.

The Trustees have achieved 30+ restoration projects within the watershed.

Restoration projects have a nexus to the injury.

Sha Dadx Project Background

The project is located on the Puyallup River near Tacoma, WA.

The project is located in the tidal fresh portion of the estuary. The lower Puyallup River has been channelized with levees so

there is very little off-channel habitat for juvenile salmon. The projects goal is to reconnect an old river meander as off

channel habitat for salmon. Reduced off channel habit is a factor that limits the ability for

Chinook salmon in the Puyallup River watershed to recover.

NORTH LEVEE ROAD

NORTH LEVEE ROAD

PUYALLUP RIVER

THE SHA DADX SITE IN 2007 PRE CONSTRUCTION

NORTH LEVEE ROAD

PUYALLUP RIVER

THE SHA DADX SITE IN 2010 POST CONSTRUCTION

26 FOOT TALL LEVEE

NORTH LEVEE ROAD

80 FOOT STEEL PIPE

We successfully reconnected the old river meander to the Puyallup which is approximately 20 acres of off channel habitat.

Fish (juvenile & adult salmon) are actually using the site. Wildlife are using the site (ducks, coyotes, many bird species)

Some Good Stuff

More Good Stuff. The Ends Justifies the DSAYs

In the Commencement Bay injury assessment we use discounted service acre years (DSAYs) as the currency to scale the restoration to the injury.

1 DSAY in Commencement Bay = $67,000 The 20 acres that we restored = 154 DSAYs 154 DSAYs ~ $10.3 million The project cost including feasibility, design, permitting, and

construction was roughly $10.9 million.

Cost Savings Are Good

Puyallup Tribe donated most of the land to the project. Savings = $2 Million

We segregated the topsoil and used it back on the site. Savings = $150,000

We salvaged timber during clearing that we used as root wad structures in the channels. Savings = $100,000

We ground up the remaining timber and used it as mulch on the site. Savings = $200,000

Job Creation is Good

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FTE 6 MONTHS INDIRECT FTE TOTAL

Not so Bad But Definitely Costly The local jurisdiction required that North Levee Road

remain open throughout the construction. We had to push 80 feet of pipe that was an inch thick and

10 ft in diameter under the working road. To do this we had to construct a pipe jacking pit on the

interior side and a receiving pit with a cofferdam on the river side.

We had to grout around the pipe to fill voids and reduce road sag.

Cost of the pipe = $1,000,000 Cost of installation = $1,000,000

COFFERDAM AND RECEIVING PIT

RECEIVING PIT/COFFERDAM

PIPE JACKING PIT

PIPE JACKING

PUSHINGRAM

AUGER TO REMOVE DIRT

More Costly Stuff

Dewatering Costly = $1,000,000 Dewatering wells every 15 feet around the levee

alignment. Needed for equipment to operate effectively on the site. Needed dryer soil to use in levee construction. Wet material used in levee lifts won’t pass specifications. Each lift of a levee must pass specifications before the

next lift is built.

DEWATERING

DEWATERING WELLS EVERY 15 FEET

The Bad Begins - Inspection Trench

6 ft deep trench around levee foot print Discovered large zone of very sandy substrate Raised concerns about seepage under the levee at higher

head pressures.

INSPECTION TRENCH

TOO SANDY

The Bad Continues and it Gets Costly

Our contractor had performed geotech studies and seepage analysis but not enough in the correct locations.

The original geotech study missed large sand lenses which led to an erroneous seepage analysis.

We performed more geotechnical studies = $50,000 Additional geotech showed a lot more sand which cascaded

into a lot of other issues.

The word SAND appears too often In this geotechnical drawing

1st Issue Related to Bad Geotech

• We couldn’t use on site material to build the levee (too sandy). Had to import all material.

• Material excavated from the site had to be disposed of off site.

• Cost increase = $1,000,000

2nd Issue Related to Bad Geotech

Performed second seepage analysis = $25,000 Seepage analysis showed that seepage/ catastrophic

piping could occur when head pressure exceeded 16 feet. Why did we design the levee to 26 feet? Cost of extra ten feet of levee $1,000,000

APPARENTLY RED IS A BADCOLOR IN A SEEPAGE ANALYSIS

3rd Issue Related to Bad Geotech

We needed to ensure that the water level never exceeded 16 feet inside the ring levee.

Buy and install a flood gate = $150,000

FLOOD GATE $150,000

Other Random Bad Things

ROAD SLUMPED

FUEL TRUCK TIPPED OVER

GARBAGE DUMP FOUND

FORK LIFT TIPPEDOVER

Lesson Learned

For large projects it pays dividends to have an independent third party perform a thorough review of the entire project design and the related studies.

Using a technical team approach with members having a diverse background may catch issues early.

When constructing larger scale restoration projects in an urban environment significant contingency funds should be factored into the budget.

Let’s Leave on a High Note