Updating EBMUD’s Water Supply Planning Model to Meet Future Challenges

CWEMF 2016

GARY PALHEGYI, P.E., D,WRE BEN BRAY, PH.D., P.E. Why a New Planning Model?

• Previous model built in FORTRAN – Many years of edits, changes and manipulation – Difficult to make code changes and integrate new components – Loosing experts that can manage the model

• Update to modern software (RiverWare) – Improved system and temporal resolution – Improved capabilities and flexibility – Improved transparency

2 Overview of System

Lower

Woodbridge ID Lodi

Walnut Creek Pump Station

3 RiverWare Schematic

PG&E Regulated Inflows

Amador County CCWD Calaveras County Intertie

Mokelumne Hill G Walnut Creek PP Jackson Valley WD Local 3 2 1 hydrology Pardee Reservoir FRWP WC FP

Local USL hydrology

G Lafayette P Chabot FP Moraga Channel Seepage, Riparian & Senior PP Release Evaporation G Appropriators USL Briones WTP Briones Lafayette North San Joaquin PP G P County WD Orinda Control Center Woodbridge ID, Woodbridge Dam San Pablo G City of Lodi

Release Orinda Sobrante FP WTP ><((((‘> Customer Demands ><((((‘> ><((((‘> Flows to Bay Delta 4 Operational Priorities

• Meet obligations for water right holders • Comply with environmental requirements – Flows and temperature • Meet USACE flood reserve requirements • Meet EBMUD customer demands

5 Water Right Holders

• PG&E (non-consumptive use) – Unimpaired Runoff  Regulated Undiminished Flow

• Upcountry – Amador County Water Agency – Calaveras County WD, Calaveras Public Utility District – Jackson Valley Irrigation District • East Bay Municipal Utility District • Lower Mokelumne River – North San Joaquin Water Conservation District – Woodbridge Irrigation District, City of Lodi – Riparian and Senior Appropriators

6 Environmental Flow Requirements

Below Camanche Below Woodbridge Below Camanche AN/N BN D CD AN/N BN D CD 푅 = 푚푎푥 Below Woodbridge + diversions and losses Month [cfs] [cfs] Oct 1-15 325 250 220 100 100 100 80 15 Oct 16-31 325 250 220 130 100 100 80 75 Nov 325 250 220 130 100 100 80 75 Dec 325 250 220 130 100 100 80 75 Jan 325 250 220 130 100 100 80 75 Feb 325 250 220 130 100 100 80 75 Mar 325 250 220 130 100 100 80 75 Apr 325 250 220 130 150 150 150 75 May 325 250 220 100 300 200 150 15 Jun 325 250 100 100 300 200 20 15 Jul 100 100 100 100 25 20 20 15 Aug 100 100 100 100 25 20 20 15 Sep 100 100 100 100 25 20 20 15

Woodbridge Golf Year Type AN Above Normal N Normal BN Below Normal D Dry CD Critically Dry

7 Environmental Flow Temperature Requirements

Goal: Maintain cold water temperatures in the Lower Mokelumne River • Maintain Camanche hypolimnetic volume 28 TAF thru October • Colder than 16.4 degrees Celsius • Supported by Pardee Reservoir

Observed

Modeled

28 TAF

8 Flood Reserve Requirements

Sept 15th May 31st Jul 31st

Rain Reserve

Snow Melt 130 TAF Reserve

200 TAF Nov 5th Mar 15th Jun 30th

9 Fixed Demand Model

 Level of Development  Discretized into 5 treatment plants  Annual Average Demand For example: Walnut Creek Filter Plant

Modeled Drought Contingency Planning

• Drought Planning Sequence • Customer Demand Rationing • Freeport Regional Water Project – CVP Drought Contingency Supply • Need for Water – Transfers

11 Drought Planning Sequence

• 1976, 1977 and modified 1978

560 TAF

• Which drought LOD = 2040

is more severe?

(TAF)

12 Rationing Guidelines

Drought Projected End-of-September Rationing Goal Stage Total System Storage (TAF)

Normal 500 TAF or more None

Moderate 500 – 425 TAF 0 to 10% - Voluntary

Significant 425 – 390 TAF 10% to 15% - Voluntary

Severe 390 – 325 TAF 15% to 20% - Mandatory

Critical Less than 325 TAF 20% - Mandatory

13 Freeport Regional Water Project

• Eligible when EOS-TSS < 500 TAF

• Contract limits (1-year, 3-year)

Drought Year First Year July Start at 85.4 cfs First Year July Start at 110 cfs

1st 41 TAF 53 TAF 2nd 62 TAF 80 TAF 3rd 62 TAF (165 TAF limit) 32.4 TAF (165 TAF limit) 4th Repeat pattern Repeat pattern etc.

14 Need for Water – Example Demand Reduction

2040 LOD Demand Deficiency

Drought Planning Sequence

15 Pardee Reservoir

Modeled Observed RMSE = 22 TAF

16 Camanche Reservoir

Modeled Observed RMSE = 32 TAF

17 Draft from Pardee Reservoir

2010 LOD, 216 MGD

Comparison to OBSERVED daily data 18 Briones Reservoir

San Pablo Reservoir

USL Reservoir

19 Questions?

[email protected] [email protected] 510-287-2068 510-287-0206 Forecasting Future Storage

Carryover Storage CVP drought supply EOS TSS March 1st

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

Rationing EOS TSS April 1st

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

JSA Year Type (Oct thru Mar) P+C Storage Oct 1st

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

21 Comparison of Flows at Golf

5000 Difference in Volume = -0.050% 4500 RMSE = 41 cfs 4000

3500 y = 1.006x R² = 0.996 3000

2500

2000

Predicted Flows (cfs) Flows Predicted 1500

1000

500

0 0 1000 2000 3000 4000 5000 Observed Flows (cfs) 22 Year Type Designation

• Environmental Flow Requirements (JSA) – AN, BN, Dry, Critical – April thru September (runoff from Oct thru Sept) – October thru March • Oct 1st: forecast Nov 5th Pardee+Camanche storage

• Riparian & Senior Appropriators Diversions – Runoff volume (runoff from Oct thru June) – RSA year type (< or ≥ 250 TAF)

• Woodbridge Irrigation District/Lodi Diversions – Pardee Inflows (Oct thru Sept) – WID year type (< or ≥ 375 TAF)

23 TRA Calibration – Runoff (base flows and storm flows)

Comparison of Computed Local Runoff to Observed San Pablo Creek Flow 0.60 Measured Flows

Computed by Rational Formula with Baseflows added 0.50

0.40

High flows exceeded gage capacity, no data recorded, gaged damaged

0.30

storm flows

Discharge (AF/acre /month) (AF/acre Discharge 0.20 base flows

0.10

0.00 Apr-83 Oct-83 Apr-84 Oct-84 Apr-85 Oct-85 Apr-86 Oct-86 Apr-87 Oct-87 Apr-88 Oct-88 Apr-89 Oct-89 Apr-90 Oct-90 24 Pardee+Camanche Storage - OBSERVED

RMSE RiverWare = 50 TAF

RMSE 2000 to 2012 = 23 TAF RMSE using EBMUDSIM = 75 TAF

25 Total System Storage - OBSERVED

RMSE RiverWare = 58 TAF RMSE 2000 to 2012 = 25 TAF RMSE using EBMUDSIM = 80 TAF

26 TRA Calibration

Local hydrologic parameters Measured Inflows

Precipitation Watershed runoff (storms, base flows) Measured Measured Evaporation Storage Draft Seepage/leaks

Measured Outflows

27 RiverWare Workspace

28 True Natural Flow & Year Type

29 Calibration Procedure

USGS @ Mokelumne Hill G

Local hydrologic parameters

Pardee Reservoir JVID Aqueduct Draft Precipitation (Seepage = 16-18 cfs) Computed Pardee Outflows Test for Storm runoff G Goodness-of-Fit Observed Pardee Outflows Evaporation Seepage/leaks Camanche Reservoir (Seepage = 8-12 cfs)

Computed Camanche Outflows Test for G Goodness-of-Fit USGS @ Camanche Dam

30