Draft Plan for Gravel Placement Below New Bullards Bar Dam
YRDP Relicensing Participants
August 26, 2015
1.0 Background
1.1 Description of FERC Project
1.1.1 Facilities
1.1.2 Reservoirs
1.1.3 Project-affected Stream Reaches
1.2 Purpose and Goals/Objectives of Plan
Since its construction in 1970, New Bullards Bar Dam has effectively trapped
100% of course substrate from the North Yuba River upstream of the dam. Over
the past 45 years, this has blocked sediment supply to and created a deficit of inchannel coarse substrate storage in the reaches of the Yuba River downstream of
the dam and upstream of Englebright Reservoir. Table 3.4-1 of YCWA’s final
license application for the Project estimates approximately 51,191 tons/yr. of
bedload material would be supplied to the North Yuba River in the absence of
New Bullards Bar Dam. To mitigate Project effects on substrate supply and
storage in the reaches of the Yuba River below New Bullards Bar Dam, YCWA
will supply a mix of material of appropriate size and volume, as described in
section 2.0 below, in the North Yuba River below the dam.
The objective of this plan is to improve river habitat in the North Yuba River
downstream to the confluence with the Middle Yuba River. High water velocities
during spillway operation will facilitate gravel transport in the North Yuba River,
thus enabling gravel deposition in downstream reaches by transport from a single
area of instream gravel placement. Course bed features such as large boulders
will function to retain gravel material during high flow events.
1.3 Description of Spawning Gravels
1.3.1 Definition
1.3.2 Importance as a habitat element
2.0 Adaptive Management Strategy for Gravel Augmentation
2.1 Gravel/Cobble Placement
Within five years of License issuance YCWA will:

Map the channel geometry and model the hydraulics of the New Bullards
Bar spillway pool and tailout (~200 meters) to determine critical velocities
that will initiate movement of stockpiled gravel and cobble (0.25-6 inch
materials).

Develop a plan for initial gravel/cobble placement in consultation with the
State Water Board, Cal Fish and Wildlife, BLM, Forest Service, Foothills
Water Network, and other interested entities.



Place 5,000 tons of mixed gravel/cobble 0.25 to 6 inches in diameter
downstream of the New Bullards Bar spillway on the North Yuba River.
Conduct a baseline evaluation of the initial stockpile to document the size
and extent of gravel and cobble.
Markers (e.g., PIT tags, paint) will be used on gravel and cobble placed
under this plan to inform the monitoring phase on the retention and gross
movement of gravel and cobble. (method and subsample for marking to be
determined)
2.2 Gravel Monitoring in New Bullards Bar Reach
 Photo points will be established for the gravel stockpile and at least three sites
downstream to be selected in consultation with the State Water Board,
CDFW and the FS. Photos will be captured at each monitoring event.
 After first spill event of 2000 cfs, when feasibly possible and safely accessible, the
Licensee shall monitor changes to the gravel stockpile and areas of
downstream deposition of gravel in the NBB reach. Monitoring by the same
method will occur after each subsequent spill event over 2,000 cfs for four spill

events1, or until all gravel/cobble has been flushed from the New Bullards
Bar reach, whichever occurs first.
During each monitoring event, licensee will:
o
Survey the aerial extent and depth of the stockpile to estimate the
volume of the remaining stockpile and the volume of gravel and
cobble transported.
o
Survey the NBB reach to locate and characterize gravel/cobble
deposits. Survey methods will utilize markers, GPS, photos and
geomorphic descriptors.
o
Quantify the amount of gravel retained at large woody material
(LWM) anchored sites or in association with transported and
depositied LWM (see LWM Management Plan)
o
Describe habitat changes such as gravel bar formation and riparian
vegetation recruitment (to be determined in the Aquatic
Monitoring Plan).
2.3 Consultation
Within 1 year following completion of monitoring, YCWA will consult with the State
Water Board, Cal Fish and Wildlife, BLM, Forest Service, Foothills Water Network, and
other interested entities on the results of the monitoring and possible management
actions.
 Consultation will include a presentation on the monitoring results, distribution of
raw data collected, a discussion of the successes and/or failures of the project, a
discussion of the new flood control outlet’s as-built use and capacity, and a
discussion regarding the feasibility and projected benefits of continuing
1
Spills from New Bullards Bar Dam typically occur in 50% of the years of the historical record
with an average peak flow of 14,478 cfs, including spills below 2,000 cfs classified as
“operational” releases.


gravel/cobble placement in New Bullards Bar reach. Consultation will consider
the contribution of gravel placement from the New Bullards Bar reach to the
Yuba River.
Depending on projected costs, benefits, and feasibility, future management
actions will be collaboratively determined by the agencies and YCWA. The
agencies may defer recommending management actions until after the new flood
control outlet is constructed and tested.
Future management actions could include, but are not limited to: 1) discontinuing
placement of gravel/cobble in the New Bullards Bar reach, 2) additional pilot
projects for gravel/cobble placement in the New Bullards Bar reach, 3)
subsequent gravel/cobble placement to replenish the gravel stockpile of up to
5,000 tons every five years for the term of the license.