hydrology presentation

Hydrology Presentation

Yuba River Development ProjectFERC Project 2246 Relicensing

Thursday, November 10, 2010

Yuba River Development Project (YRDP) – FERC Project 2246 Relicensing

Meeting Agenda

Introductions Previous Meetings Updated Hydrology Project Operations


Previous Meetings 3/15/2011 – Conference Call

Presented hydrology approach Focus of discussion on accretions Action items:

Investigate sources of difference between area-weighted and mass balance methods Investigate more robust calculations of accretion flow

4/28/2011 Presented revised hydrology with precipitation adjustment to area weighted method Showed how gage error could be used to explain difference between synthetic and mass-balance

computed flows Concerns remained about differences between synthetic and mass-balance computed flows

5/15/2011 – Conference Call Presented potential gaging error at Colgate and Smartsville as explanation for differences between

synthetic and mass-balance flows. YCWA indicated concerns about YB/DS unimpaired flows Action Items:

YCWA to continue to evaluate potential sources of gaging error YCWA to revisit analysis of unimpaired flow (hold discussions with R. Jones)


BackgroundYRDP Relicensing uses a mix of historical gaged flows and synthetic accretions.

NBB accretion inflow is 33% of total NBB Inflow

Englebright accretion inflow is 35% of totalEnglebright inflow (excluding NBB inflow)


Background

Accretions are synthesized according to the formula:Flow1 = (Area1/Area2) * (Precip1/Precip2) * Flow2

New Bullards Bar Reservoir accretions use both Oregon Creek and North Yuba near Goodyears Bar as index flows (Flow2)

Englebright Reservoir accretions use Oregon Creek as index flow

Precipitation based on PRISM 30-year annual average


Area-Weighted Method Compared to Mass-Balance Method

Mass-Balance Method inherently must use downstream gage flow (Colgate or Smartsville) minus upstream gage flow in the calculation Both Colgate gage and Smartsville gage are measuring

about 3 times the flow volume that we are trying to synthesize.

Colgate gage + NBB storage change - upstream gages Therefore, a X% deviation in gage measurement results in an 3X%

deviation in computed accretion flow A “good” USGS gage rating has an assumed measurement

deviation of about 5% Therefore for our use a “good” gage rating could result in a 15%

deviation in accretion flow volume


Comparison of New Bullards Bar Reservoir Accretion Calculation Methodologies

10/1

/99

3/31

/00

9/29

/00

3/30

/01

9/28

/01

3/29

/02

9/27

/02

3/28

/03

9/26

/03

3/26

/04

9/24

/04

3/25

/05

9/23

/05

3/24

/06

9/22

/06

3/23

/07

9/21

/07

3/21

/08

9/19

/08

3/20

/09

9/18

/09

3/19

/10

9/17

/10

0500

1,0001,5002,0002,5003,0003,5004,0004,5005,0005,5006,0006,5007,0007,5008,0008,5009,0009,500

10,000Mass-Balance Timeseries Area-Weighted Flow Timeseries

Flow

(cfs

)


Examination of NBB Mass BalanceDifferences between mass balance and synthesized flow are explainable by potential variations in gage data:

Colgate PH gage variations 1% 1971-1980 5% 1981-1994 6% 1995-2002 2% 2003-2010

0

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,00014,000,000

16,000,000

18,000,000Original Comparison

Mass Balance-Based Accretion Accumulated Volume (AF)

Area

-Wei

ghte

d Fl

ow A

ccum

u-la

ted

Volu

me

(AF)

0

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

14,000,000

16,000,000

18,000,000Revised Comparison


Area

-Wei

ghte

d Fl

ow A

ccum

ulat

ed

Volu

me

(AF)


Correction of Colgate Gage Error

Study by Frank Lynch (formerly of PG&E) of acoustic doppler gages on Colgate penstocks.

Identified installation error affecting 10/2007-5/2011 Revised flows included in mass-balance comparison Corrected data submitted to USGS and incorporated in relicensing data

10/1/07 2/28/08 7/27/08 12/24/08 5/23/09 10/20/09 3/19/10 8/16/100

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

Revised Colgate FlowsOriginal Colgate Flows


Comparison of Englebright Reservoir Accretion Calculation Methodologies

10/1

/99

3/31

/00

9/29

/00

3/30

/01

9/28

/01

3/29

/02

9/27

/02

3/28

/03

9/26

/03

3/26

/04

9/24

/04

3/25

/05

9/23

/05

3/24

/06

9/22

/06

3/23

/07

9/21

/07

3/21

/08

9/19

/08

3/20

/09

9/18

/09

3/19

/10

9/17

/10

-500

-250

0

250

500

750

1,000

1,250

1,500

1,750

2,000Mass-Balance Timeseries Area-Weighted Flow Timeseries

Flow

(cfs

)


Examination of Englebright Mass Balance

Looked at effect of potential gage variations at:Colgate gage- as described for NBBSmartsville gage- 6% 1971-1977 8% 1978-1982 8% 1993-1994 2% 1995-2010 No Oregon Creek

data for 1996

01,000,0002,000,0003,000,0004,000,0005,000,0006,000,0007,000,0008,000,000 Revised Comparison


Area

-Wei

ghte

d Fl

ow A

ccum

u-la

ted

Volu

me

(AF)

01,000,0002,000,0003,000,0004,000,0005,000,0006,000,0007,000,0008,000,000

Original Comparison


Area

-Wei

ghte

d Fl

ow A

ccum

ulat

ed

Volu

me

(AF)


Middle and South Yuba River Unimpaired Flows

Disclaimer: YRDP unimpaired flows were originally included on PIP Hydrology CD. Unimpaired flows are not a part of hydrologic alteration or operations modeling

Background: YB/DS published unimpaired flows at Jones Bar and Our House Dam as part

of their Hydrology CD. Comparison of those unimpaired flows with simulated unimpaired flows at

Milton Diversion Dam, below Bowman Reservoir, and at Langs Crossing indicated an inconsistency in the downstream flow calculation

YCWA elected to compute accretions independently


Unimpaired Middle Yuba River at Our House Dam

Uses unimpaired flow below Milton Diversion Dam from YB/DS

Synthesizes accretions between Milton DD and Our House Dam based on area-weighted precipitation adjusted flow method previously described, using Oregon Creek as the index watershed.

Double checked against available gaged accretions (10/1/1987-9/30/2007) R2 = 0.87


Unimpaired South Yuba River at Jones Bar

Uses unimpaired flow at Langs Crossing and below Bowman Reservoir from YB/DS

Computes accretions directly from USGS gages at Langs Crossing, below Bowman Reservoir, and at Jones Bar for full period of record.


Accumulated Unimpaired Flow at Smartsville

Computed unimpaired Yuba River flow at Smartsville by adding: Gaged North Yuba River flow at Goodyears Bar Computed unimpaired Middle Yuba River at Our House Dam Computed unimpaired South Yuba River at Jones Bar Synthesized YRDP accretions above Englebright Dam

Compared to DWR published Full Natural Flow for the Yuba River at Smartsville (CDEC YRS) for 1976-2008

LocationAverage Monthly Flow (cfs) Total

(TAF)Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Computed Unimpaired Flow 430 1,286 3,067 4,520 5,311 6,027 5,940 6,452 3,195 910 354 307 2,274

DWR Full Natural Flow 479 1,470 3,236 4,672 5,537 5,984 5,640 6,123 2,997 907 329 304 2,266

Difference-49

-10%

-184

-13%

-169

-5%

-152

-3%

-226

-4%

43

1%

300

5%

239

4%

198

7%

3

0%

25

8%

3

1%

8

0.4%


Accumulated Unimpaired Flow at Smartsville

0 10,000,000 20,000,000 30,000,000 40,000,000 50,000,000 60,000,000 70,000,000 80,000,0000

10,000,000

20,000,000

30,000,000

40,000,000

50,000,000

60,000,000

70,000,000

80,000,000

DWR Published Full Natural Flow at Smartsville (AF)

Synt

hesi

zed

Unim

paire

d Fl

ow a

t Sm

arts

ville

(AF)


Closer Look at Monthly Timeseries for Unimpaired Flow at Smartsville

05/07/90 01/12/91 09/19/91 05/26/92 01/31/93 10/08/93 06/15/94 02/20/95 10/28/95 07/04/96 03/11/97 11/16/97 07/24/980

5,00010,00015,00020,00025,00030,00035,00040,00045,00050,00055,00060,00065,00070,00075,00080,00085,00090,00095,000

100,000

DWR FNF Synthetic Unimpaired

Flow

(cfs

)


Now on to Project Operations

Overview of Yuba River facilities to be included in YRDP operations simulation Slate Creek Diversion Dam (SFWP facility) Our House Dam and Lohman Ridge Tunnel Log Cabin Dam and Camptonville Tunnel New Bullards Bar Dam and Colgate Powerhouse Englebright Dam (USACE facility), Narrows 1 Powerhouse

(PG&E facility), and Narrows 2 Powerhouse Daguerre Point Dam (USACE facility)

YRDP operational drivers


Yuba River Development Project Operations Model Coverage


Slate Creek Diversion Dam

On Slate Creek (RM 8.8) Owned and operated by SFWP Not actively operated through

most of the year Minimum flow below dam

Currently 10 cfs Varies monthly from 10-49 cfs

under new license Diverts to Slate Creek Tunnel

600 cfs capacity


Slate Creek Diversion Dam

Typically minimal active operation: Only make changes when required by water right or FERC

requirements Two potential modes of simulated operation:

Use historical flows from gage below dam (USGS 11413300)

Compute inflows based on gage below dam and gage on tunnel (USGS 11413250) Re-operate facility according to water rights and Slate Creek

flow requirements Ignore SFWP operations


Our House Dam On Middle Yuba River (RM 12.3) Minimum flow below dam:

Varies monthly from 30-50 cfs Releases made through a 24

inch dia. low-level outlet at base of dam (60 cfs capacity)

Diverts to Lohman Ridge Tunnel 850 cfs capacity Tunnel intake consists of a weir

with a trashrack


Our House Dam

Minimal active operation Set low-level outlet according to downstream flow

requirement Flow above minimum flow requirement plus a buffer flows

into Lohman Ridge Tunnel Once Lohman Ridge Tunnel capacity is filled, remaining

Middle Yuba River flows spill over Our House Dam


Log Cabin Dam On Oregon Creek (RM 4.2) Around 100 feet below Lohman

Ridge Tunnel outfall Minimum flow below dam:

Varies monthly from 8-12 cfs Releases made through a 18

inch dia. low-level outlet (13 cfs capacity)

Diverts to Camptonville Tunnel 1,100 cfs capacity Tunnel intake consists of a

weir and a trashrack Diverts flow into New Bullards

Bar Reservoir


Log Cabin Dam

Similar operations as Our House Dam Low level outlet is set to meet downstream flow

requirement Flows above minimum flow into Camptonville Tunnel Flows above Camptonville Tunnel capacity spill over Log

Cabin Dam to Oregon Creek


New Bullards Bar Dam and Reservoir

On North Yuba River 966,000 acre-foot storage capacity Up to 170,000 acre-feet of flood

control reservation Receives diversions from

Camptonville Tunnel Releases through:

Colgate Penstock (3,430 cfs capacity)

Low-level outlet (1,200 cfs limit) Fish Hydro (6 cfs capacity Spillway (167,000 cfs capacity)


Colgate Powerhouse

On Yuba River (RM 33.5) 5.8 miles below Middle Yuba

River Approx 1 mile above

Englebright Reservoir normal maximum water surface

Twin pelton wheel turbines 340 MW capacity

(FERC nameplate is 315 MW)


New Bullards Bar Dam and Reservoir and Colgate Powerhouse

Complex operations: Flood management – Flood control reservation + downstream

objective flows Yuba River Accord – Lower Yuba River flow requirements PG&E Power Purchase Agreement – Cooperatively manage

reservoir storage and releases to provide power value Target Storage operations (to be discussed) FERC Requirements – Minimum flows on Middle Yuba, Oregon

Creek, North Yuba River, and Lower Yuba River. Also ramping rates

Agricultural deliveries from diversions near Daguerre Point Dam Water supply carryover storage targets


Englebright Dam and Reservoir USACE facility

Sediment management Approximately 70 TAF of storage

Approximately 8,500 AF of storage currently exercised

Approximately 1.8 MAF of annual releases (WY 1970-2010)

Releases through Narrows 1 and 2 Powerhouses Narrows 1 (PG&E): 720 cfs

capacity Narrows 2 (YCWA) 3,400 cfs

capacity Narrows 2 bypass (YCWA)

3,000 cfs capacity Spill over dam crest

181,000 cfs capacity


Englebright Dam and Reservoir

Ensures relatively stable flows to Lower Yuba River Elevations fluctuated to capture variability in Colgate Powerhouse

releases Releases to meet Lower Yuba River flow objectives

Flow requirements at Marysville and Smartsville Agricultural deliveries from diversions near Daguerre Point Dam

Captures “freshets” from Middle and South Yuba rivers New Bullards Bar Reservoir will reduce releases in anticipation of small

storm events, creating space in Englebright. Englebright storage exercised to manage small storm events through

Narrows powerhouses High volume of recreation usage

Minimum operational levels to protect marina operators


Daguerre Point Dam

USACE facility Debris management

No operable storage Provides for gravity diversion

for YCWA irrigation system


Daguerre Point Dam No operational capability Site of diversions for agricultural deliveries north and south of the Yuba

River BVID’s Pumpline Diversion (.9 miles upstream) Hallwood-Cordua Canal YCWA Main Canal or South Canal

Approximately 116,000 acres currently irrigated from the Yuba River Total build-out of approximately 120,000 acres

Approximate annual demands: 310 TAF in wet years (331 TAF future) 325 TAF in dry years (346 TAF future)

Annual contracts and water rights for 386 TAF No historical shortages

Previous analyses imposed shortages to ensure sufficient storage to make minimal deliveries in following years assuming extreme drought conditions


Next Steps

December: Meeting to discuss agricultural demands and detailed operations of New Bullards Bar and Englebright reservoirs

February-March: Meeting for initial release of operations model

hydrology presentation

Documents

smartsville gage

calculationboth colgate

upstream gage flow

downstream gage flow

gage data

massbalance flows

nbb accretion inflow

good gage rating