Gold Ray Dam Removal Monitoring Outline OSU Biological and Ecological Engineering

sugarannoyedUrban and Civil

Nov 16, 2013 (3 years and 10 months ago)

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Gold Ray Dam Removal Monitoring
Outline



OSU Biological and Ecological Engineering

Summary Narrative:

In concert with work already underway at Savage Rapids, additional monitoring to consider for Gold Ray Dam is outlin
e
d
below. This work
compliments and will benefit from

other monitoring
proposed by
collaborators on GRD monitoring
(e.g. SOU, Bob Hughes/Amnis Opes, ODFW,

RVCOG, USGS

etc.)
.

Monitoring Objective: Investigate the spatial and temporal effects of removing Gold Ray Dam on

geomo
rphology,
ha
bitat and sediment
dynamics.

To contribute to broader sciences (river management, ecology, geomorphology), results will be placed within the
context of natural variability and measurement error, and will be compared to scientific consensus on

underlying
processes contributing to changes.

Spatial extent
will

include reservoir area and

downstream to Savage Rapids (approx
.

15
river miles)
. Downstream
sediment
sampling
locations and
densit
ies
, described below,

will be based on

a) mapping of
poten
tial deposition zones through

calculations of stream power
to transport sediment
and statistical power

to detect
effects
, and b) coordination with other monitoring efforts
.

Coordination
:

Edge of water surveys
will be
coordinated with SOU

during summer low water
.

OSU
will involve

SOU
students in mapping and

surveying to share information on RTK GPS survey
techniques, and SOU students will assist
with OSU field work.

We will consult with Amnis Opes regarding river navigability downstream

of the dam.



Sediment Investigations

Our expectation is that sand deposition would likely be minimal in the steeper “transport” reach below Gold Ray dam.
We propose a
primary

study reach with the upper boundary at Valley of the Rogue State Park and co
ntinuing down to
the former site of Savage Rapids Dam. (This coincides with the ODFW redd count/carcass survey site ‘Middle A’ (VOR)
from Valley of the Rogue State Park to the town of Rogue River).


We will measure longitudinal profile, pool depth and
vo
lume. We will survey existing gravel bars to obtain extents and volumes, an
d

collect surface grain size measurements
(Wolman 1954) along bar margins and on the downstream 1/3 of bars. These areas are of particular interest due to
their importance as spa
wning areas for spring and fall Chinook salmon, and the risk that gravel interstices could be filled
with sand evacuated from the reservoir.
We plan to
survey the pool depths and longit
udinal profile of the reach directly
below

Gold Ray Dam to Valley of
the Rogue state park to examine the potential of larger
gravels depositing in pools.
While we

do not
explicitly
plan to survey bars and perform surface sedime
nt assessments in this reach, the spatial
extents of the study should remain adaptable to accommo
date logistical challenges and allow for familiarization with
the site.



We will sur
vey the reservoir extensively
directly after drawdown and
during

low water each year to determine the
initial sediment volume as well as the volume and spatial extents

o
f sediment evacuated. We will also collect surface
grain size distributions along transects. Reservoir surveys will include the major sloughs

(Lower Kelley and Tolo)

now
inundated by Gold Ray Dam.

ADDITIONAL INVESTIGATIONS TO BE TARGETED: While not incl
uded as part of this proposal, we will target additional
funding to investigate bedload transport in order to develop a more complete and credible sediment budget below Gold
Ray Dam. Gravels (15% of total stored sediment



Elliot and Dittmer 2009
) will mo
ve exclusively as bedload and sand
(75% to total stored sediment) will move partially as bedload, depending on stream power and local hydraulics. We
would attempt to gather at least 5 samples (Equal Width Increment, Helley Smith 8055 or similar cable dep
loyed
sampler) at a range of applicable discharges. These samples would need to be collected at the nearest possible
downstream bridge crossing, either the railroad bridge at Gold Hill or the Rock Point Bridge.



References


Elliot and Dittmer, 2009.

Preliminary Report of the Sediment Study Conducted at Gold Ray Reservoir, Jackson
County, and Oregon

Wolman, M.G., 1954. A method of sampling coarse river bed material. Transactions of the

American Geophysical Union 35(6): 951
-
956.




Table
1. S
ummary
of

proposed monitoring actions

Action

Justification

Expected Outcomes

Surface sediment analysis (pebble
counts and bulk samples) along bar
margins downstream and limited
sampling in the reservoir area.


Downstream sediment transport and
deposition; grain size and intrusion of sands
that influence spawning habitat quality.

-

Surface grain size
distribution along
salmonid spawning
habitat in bar margins

-

Description of erosional
processes in reservoir

GPS
ground surveys


bars and
reservoir sediments

Documentation of the creation of channel
features and habitat complexity in formerly
sediment starved reach Will be used to develop
sediment budget of the removal.

-

Change in bar volumes

-

Yearly volume estimates
of sediment evacuated
from reservoir

Sonar and ADCP profiles of channel
and pools

Calculation of holding habitat changes (e.g.
residual pool depth) due to deposition in pools
and slackwater areas downstream of the
removal; Development of longitudinal prof
ile.

-

Residual pool depths,
widths

-

Change in pool volumes

-

Longitudinal profile of
thalweg

-

Variability in
velocity/depth

-



Activities in addition to field investigations:

-

Data processing

-

Presentations of monitoring progress and findings at appropriate
community meetings

-

Website with data posted in accessible format

(example
-

spatial data library at
http://rivers.bee.oregonstate.edu/ChiloquinDamRemoval.html
)

-

Annual updates

-

Development of public
ations/presentations in conjunction with
other monitoring gr
oups