The Rock Creek Project: Contact and Site Information                        

Original March 7, 2004

                                                                                                                        Last Updated  Feb 5, 2005


FERC # 11866-000 California  -          Currently  -

2/1/05              Stage 1 Consultation Complete

Stage 1 Consultation Studies in process

Engineering Review by PG&E

Distribution Interconnection review in process

Permit Holder:

Davis Hydro, LLC

                        Principal and Contact:

                        Richard D. Ely

                        Davis Hydro, LLC

                        27264 Meadowbrook Drive

                        Davis, CA 95616


Phone                                       Weekends                                530 753-8864 (Home office)

                                                Weekdays                                530 753-0562 (Hydro office)

Fax                                                                                          530 753-4707


Web site 



Proposed project Description


Location                       Rock Creek Diversion Dam – adjacent to State Rt-70 at milepost PL-12.3.

Electrical service:          21 kV three phase service existing on site. 

Total Size                     0.5 MW  (maximum) Design depends on final design. 


Initial plans were 3 or 4 generators:


Original Generator                 (1) 700 KW induction or synchronous

Plan                                         (1) 500 KW induction

(1)   300 KW)


Current plans (1-02-05) are under discussion with PG&E.  Current design under discussion has one turbine with a maximum capacity of 500 kW and an initial operating point at 400 kW, subject to continuing review and possible monitoring of transmission limitations.  The turbine is planned, at present, to be located in the lower gate chamber just downstream of center abandoned gate.  Exact sizes are to be determined by detailed design and fisheries requirements.


Design Constraints:


Consultation with PG&E has also indicated they need something like 120 cfs of water through the 30” river release penstock to maintain a low sediment level in front of its trash rack.  Aural observation confirms that small gravel is passing through the pipe during recreation releases from the sluice gate.  The exact amount is unknown and subject to ongoing review by PG&E.


The lower gates are buried under 40 or more feet of gravel and sand.  Their operators have been electrically disconnected, and they are considered by all parties to be abandoned.  This suggests the opportunity of using the lower gate chamber for a turbine site.  A similar idea was proposed by PG&E for a 1985 micro-hydro project in the same place.  That design used the water in the lower conduits; current design is to operate on a tap off of the 30 “river release” conduit.



Interconnection Discussion


{Topics below this point have not been agreed to by any party. 

They are the products of informal discussions.}


Informal indications has been received from PG&E in December 2004 that it is possible to export 400kW from this site without major distribution system upgrades.  Levels above that are subject to review and modification as conditions permit.  With that informal guideline, Davis Hydro is designing the system to 500 kW maximum with an initial operating point at about 400 kW with the expectation that operation over 400 kW will be subject to field conditions.



PF Caps

To reach 95 % PF (or as specified by PG&E) on induction units

Electrical Interface

Three phase manual ganged air breaker (normal dual access/lock-out)


3 phase 21 kV manual fused CL pull disconnects to protect transformer


PGE: primary or secondary per discussion with PG&E. Davis Hydro has no preference.

Primary Service

Wye or Delta and grounding options per PG&E recommendations.


500 KVA transformer   21 kV /4160/2400  (Delta/Wye)

21 KV/ 208/120 (possibly off existing dam service )

Transformer located in or near the Diversion gatehouse

Connections to dam

Use of abandon conduits.


At Gatehouse


Expected generation will be 24 hours/day  - 365 days per year.  Required fisheries release.

The site will produce approximately 4 GWH/year.


Control  (Current design – 5/1/05)


Control of hydro gate can be operated by PG&E.  By moving the flow gauge, there will be no change in their operation of their software.  The turbine will act as a 90 cfs “leak” off of the existing 30” river release decreasing the amount through the control butterfly.


Operation and Maintenance:

Davis Hydro will operate and maintain equipment under PG&E’s direction, or PG&E can operate site.

Davis Hydro will maintain the equipment. 

All scheduled outages will be by arrangement and notice to PG&E.


Relaying::   Per PG&E Requirements 


Additional relaying at option of applicant

Relaying sensing:

·        Primary phase to ground faults (off metering PTs)

·        Secondary phase imbalance (measured open Delta)

·        Secondary ground fault (by generator)

·        Thermal overheat, vibration, and noise check

·        PLC failure

·        PLC operation and reclosure coordination with sluice gate


Lightning and surge protection:

Consultation with PG&E’s field engineering staff.

We will lower grounding impedance at service drop.


Sluice gate automatic control:

Discussions with PG&E on better control opportunities to be supplied by DH to PG&E as part of lease


Inlet design:

                        To meet FERC (fisheries) requirements.  No change is proposed.


Telephone access:  

                        Shares phone access conduits with PG&E.  New phone line will be installed