CC 2019-04-23_11c Monthly Water Supply and Demand March 2019_Two Year ProjectionsMEMORANDUM
TO: CITY COUNCIL
FROM: BILL ROBESON, PUBLIC WORKS DIRECTOR
BY: SHANE TAYLOR, UTILITIES MANAGER
SUBJECT: MONTHLY WATER SUPPLY AND DEMAND UPDATE AND TWO-YEAR
WATER SUPPLY AND DEMAND PROJECTIONS
DATE: APRIL 23, 2019
SUMMARY OF ACTION:
The update reports the water supply and demand for March 2019. Current Lopez
Reservoir level and projected levels are provided in the attachments.
IMPACT ON FINANCIAL AND PERSONNEL RESOURCES:
Approximately two (2) hours of staff time is required to prepare the report.
RECOMMENDATION:
It is recommended the City Council receive and file the monthly Water Supply and
Demand Report and two-year Water Supply and Demand projections.
BACKGROUND:
On April 25, 2017, the City Council, by resolution, rescinded the Stage 1 Water Shortage
Emergency along with related emergency water conservation measures and restrictions.
During the public hearing the City Council requested staff to continue preparing the
monthly water supply and demand updates. The Council urged citizens to continue to
practice every day water saving measures, and reiterated that the previously adopted
water saving measures were to remain in effect.
In March 2019, the City’s water use was 130.4 acre-feet with a per capita use of 78 gallons
per day/per person. There was a total of 3.3” of rainfall in March. The water use for the
current “rolling” water year from April 2018 to March 2019 was 2,121 acre-feet, which
equates to a per capita use of 107 gallons per day/per person. There was a total of 18.1”
of rain fall for this period.
ANALYSIS OF ISSUES:
The United States Drought Monitor, as of April 11, 2019 shows San Luis Obispo County
in a normal condition. Rainfall to date (July 1, 2018 to April 12, 2019) is 17.6 inches at
Item 11.c. - Page 1
CITY COUNCIL
MONTHLY WATER SUPPLY AND DEMAND UPDATE AND TWO-YEAR WATER
SUPPLY AND DEMAND PROJECTIONS
APRIL 23, 2019
PAGE 2
the Corporation Yard rain gauge. Lopez Lake, as of April 11, 2019 is at 59.2% capacity
(29,243 acre-feet of storage).
The projected water use in water year 2018/19 was 2,000 acre-feet. The actual use was
2,121 acre-feet.
The new water year began on April 1, 2019 and the current total available supply from
Lopez is 2,290 acre-feet, our normal entitlement. In addition, we have 1,323 acre-feet of
ground water entitlement from the Santa Maria Basin and 200 acre-feet from the Pismo
Formation. In addition, we have 378 acre-feet of available surplus water from Lopez. The
projected water use for 2019/20 is 2,200 acre-feet. In conclusion, based on average
rainfall for the next two years, the current supply will meet the projected demand.
ADVANTAGES:
No advantages noted at this time.
DISADVANTAGES:
No disadvantages noted at this time.
ALTERNATIVES:
Not applicable at this time.
ENVIRONMENTAL REVIEW:
No environmental review is required for this item.
PUBLIC NOTIFICATION AND COMMENTS:
The Agenda was posted at City Hall and on the City’s website in accordance with
Government Code Section 54954.2.
Attachment:
1. Water Year 2019 Water Supply and Demand Update Presentation
Item 11.c. - Page 2
1 April 23, 2019
City Council Meeting
SOQUEL CREEK
WATER DISTRICT
Water Year 2019
Water Supply &
Demand Update
ATTACHMENT 1
Item 11.c. - Page 3
2
Presentation Topics
•Background
•Supply Summary
•Demand Summary
•Two Year Water Supply and Demand Look-Ahead
•Supporting Supply Reports
Item 11.c. - Page 4
3
Background
•April 25, 2017
–City Council rescinded Stage 1 Water Shortage Emergency
and related water conservation measures and restrictions
–Directed staff to prepare ongoing monthly water supply and
demand updates since direction
•As of April 2, 2019, the United States Drought
Monitor shows Arroyo Grande is not in a
drought classification.
•Rainfall to date (July 1, 2018 to April 4, 2019) is
17.7 inches at the Corporation Yard rain gauge.
•Lopez Lake is at 59.2% capacity (29,243 acre-
feet (AF) of storage) as of April 11, 2019
Item 11.c. - Page 5
4
Supply Summary
•May 23, 2017, the County BOS rescinded the drought
emergency proclamation. However, as recommended
by the Zone 3 Advisory Board, the BOS kept the Low
Reservoir Response Plan (LRRP) in place until March
31, 2018.
•A new Lopez water year (WY) began on April 1, 2019
with new allocations of 2,290 AF of entitlement plus
378 AF of surplus
•1,323 AF of Santa Maria Groundwater Basin (SMGB)
•200 AF from the Pismo Formation
Item 11.c. - Page 6
5
Demand Summary
050100150200250300350
January-13March-13May-13July-13September…November-…January-14March-14May-14July-14September…November-…January-15March-15May-15July-15September…November-…January-16March-16May-16July-16September…November-…January-17March-17May-17July-17September…November-…January-18March-18May-18July-18September…November-…January-19March-19SMGB (AF)Pismo Formation (AF)Lopez (AF)
SMGB (AF)
Pismo
Formation (AF)
Lopez
(AF)
Monthly
Total
(AF)
Monthly
Rainfall (in.)
Water Year
Cumulative
Rainfall (in)Population
Monthly Per
Capita Water
Use (gpcd)
April-18 0.0 0.0 161.2 161.2 0.5 0.5 17,641 99.2
May-18 1.3 0.0 201.6 202.9 0.0 0.5 17,641 120.9
June-18 1.2 0.0 213.2 214.4 0.0 0.5 17,641 132.0
July-18 4.4 0.0 209.4 213.8 0.0 0.5 17,641 127.4
August-18 10.3 0.0 211.0 221.3 0.0 0.5 17,641 131.8
September-18 2.7 0.0 212.7 215.4 0.0 0.5 17,641 132.6
October-18 7.7 0.0 189.6 197.3 0.4 0.9 17,641 117.5
November-18 2.1 0.0 175.6 177.7 1.8 2.7 17,641 109.4
December-18 0.9 0.0 147.1 148.0 1.2 3.9 17,641 88.2
January-19 0.0 0.0 127.4 127.4 5.1 9.0 17,641 75.9
February-19 0.0 0.0 111.0 111.0 5.9 14.9 17,641 73.2
March-19 3.3 2.7 124.4 130.4 3.3 18.2 17,641 77.7
Water Year
2017/18 33.9 2.7 2,084.1 2,120.6 18.2 18.2 17,641 107.3
Item 11.c. - Page 7
I
■ ■ ■
6
Demand Summary
•Historical per capita water use, measured in gallons
per capita per day (gpcd), compared to rainfall (in.)
160
138
104 96
116 107
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
200.0
0
5
10
15
20
25
30
January-13March-13May-13July-13September-13November-13January-14March-14May-14July-14September-14November-14January-15March-15May-15July-15September-15November-15January-16March-16May-16July-16September-16November-16January-17March-17May-17July-17September-17November-17January-18March-18May-18July-18September-18November-18January-19March-19gpcdin.Water Year GPCD & Rainfall
Water Year Cumulative Rainfall (in)Monthly Rainfall (in.)
Monthly Per Capita Water Use (gpcd)Water Year Per Capita Water Use (gpcd)
Item 11.c. - Page 8
--
•
7
Demand Summary WY 13/14-18/19
•gpcd correlated to rainfall using regression analysis1
1Regression analysis: statistical processes for estimating the relationships among variables (rainfall & gpcd). Focus is on the relationship
between a dependent variable (gpcd) and one or more independent variables (or 'predictors’, such as rainfall). Helps one understand
how the typical value of the dependent variable (or 'criterion variable') changes when any one of the independent variables is varied.
The observed water demand trend is assumed to be correlated to multiple factors in addition to rainfall, such as water conservation
efforts. However, it is difficult to directly and discretely calculate all factors’ impact on water use. Therefore, rainfall is a reasonably
attainable and discrete data source that can be used to project water demand due to their strong correlation with each other.
WY 13/14
160 gpcd WY 14/15
138 gpcd
WY 15/16
104 gpcd
WY 16/17
96 gpcd
WY 17/18
116 gpcd
WY 18/19
107 gpcd
Linear Regression Trendline
y = -2.52539640770057x + 153.676018235997
R² = 0.716863483869912
Polynomial Regression Trendline
y = 0.196083985151701x2 -8.67148817448877x + 189.79219110936
R² = 0.922230496414732
0
20
40
60
80
100
120
140
160
180
0 5 10 15 20 25 30Water Year GPCD "y"Water Year Total Rainfall (in) "x"
Regression
Trendline
Type
Water Year Total
Rainfall (in.) "x"
Projected GPCD Using
Regression Trendline to Solve
"y"
Actual GPCD
Comparison
Linear =-2.52539640770057 *18.2 +153.6760182360 108 107
Polynomial =0.196083985151701 *18.2 ^2-8.6714881744888 *18.2 +189.792191109360 97 107
Item 11.c. - Page 9
--............ ,( -········,
•··························· ~
_____. .... ...... ... II -,. .............. ---\ ..................................................... .
8
Two Year Water Supply and Demand
Look-Ahead
•Using the average of 107 gpcd from the regression analysis
formulas and assuming average rainfall (16 in.), projected
demand for WY 19/20 & WY 20/21 is 2,200 AF
Water Supply Source Entitlement
WY 2018/19
Actual Use (AFY)
WY 2019/20
Projected Use (AFY)
WY 2020/21
Projected Use (AFY)
Groundwater-SMGB 1,323 34 50 50
Groundwater-Pismo
Formation 200 3 100 100
Lopez 2,290 2,084 2,050 2,050
Total 3,813 2,121 2,200 2,200
0
1,000
2,000
3,000
4,000
5,000
Entitlement (AFY)WY 2018/19 Actual Use
(AFY)
WY 2019/20 Projected
Use (AFY)
WY 2020/21 Projected
Use (AFY)
Groundwater- SMGB Groundwater- Pismo Formation Lopez Item 11.c. - Page 10■ ■ ■
9
Supporting Supply Reports
Item 11.c. - Page 11
10 Item 11.c. - Page 12
Contractor
Arroyo Grande.
Oceano CSD
Grover Be.ach
Pismo Beach
CSA 12
San Mie:ue lito
Tot al
San Luis Obispo County Flood Control and \\Ta ter District
Zone 3 -Lopez Prqject -Monthly Operations Rep01i
March, 2019
EntL
2290
303
800
892
245
-i53 0
Lopez \Vater Deliveri es
This Month
Swplus Total Entitlemen t Swplus En titlement
Usage % Usage % Usage.
564 .00 2854.00 124 .37 5.4% 0 .00 0 .0% 2084.03
15 .00 378 .00 0 .00 0 .0% 19 .62 26.2% 303 .00
197 .00 997 .00 57.7 1 7.2% 9 .04 4.6% 800 .00
220 .00 1 1 12 .00 000 0 .0% 0 .00 0 .0% 89 2 .00
60 .00 305 .00 280 1.1% 0 .00 0 .0% 74 .1 3
1116 .00 56-16 .0 0 l 8U8 -i.1 % 28 .66 2.6% -il53.l6
Apri l to Present Lo pez Entitleme nt+Surp lus Water Usage
Ap.-May Jun Jul Aug Se p Oct Nov Dec Ja n Fe b Mar
'18 '18 '18 '18 '18 '18 '18 '1 8 '1 8 '19 '19 '19
j □AG ■GB O OCSD □PB ■CSA12 I
%
9 1.0%
100 .0%
100 .0%
100 .0%
30.3%
9 1.7%
April to Present
Swplus
Usage %
0 .00 0 .0%
75.00 100 .0%
9.04 4 .6%
220.00 100 .0%
0.00 0 .0%
304-0-i 27.2%
Note : Delive ri es are in acre feel One ac re foo t = 325 ,850 gallon s or 43,560 cubic feet. Safe yield is 8,730
ac re feet.
Lopez Dam Opemtions This Month Year t o Date
State \Vater D eliveries
This Month January to Pres ent
Total Annual Usa ge o/. of S WP I Change in Usage % of Annual
Aluwal
Usage % Request R,queos Deliveries Storage Request
2084.03 73 .0%
378.00 100.0% 227 10 .98 4 .8% 10 .98 4.8%
809.04 8 1.1 %
1 11 2 .00 100.0% 1 120 98 .50 8 .8% 278.55 24.9%
74.13 24.3% 27 5.55 20 .6% 15.78 5 8.4%
127 7.77 6.1% 22.50 17.7%
-i-i5 7.20 78 .9% 15 01 122 .80 8 .. 2% 76 I --i6 .80 327.8 1 21.8 %
Last MonthSton"I State Water 13ll.5l I This Momh Stoi,d State Water
January to Present State Water Usage
1i -1 ------w
Ap r May Jun Jul Aug Sep Oct N:>v Dec Jan Feb Mar
'1 8 '18 '18 '18 '1 8 '18 '18 '1 8 '18 '19 '19 '19
1 □ OCSD □PB ■ CSA12 □ SanM ig I
SWP
Deliveries
205.00
126-i.71
"Year to Date" is January to p resen t fo r State water, April lo present for Lopez deliveries, and July to p resen t
for rainfu.1 1.
Comments: Surplus water shown is as desi gnated per BOS May 15, 20 18 De<:laration of Surphis Wa te r.
Lale. Elevatio n (full at 522.37 feet) 496.59 Difference (fee t) I -25 .78 I
Storage (full at 49200 acre feet) 29008
Rainfall 5.19
Down stream Release (4200 ac re feet/year) 196 .4 1
Spillage (acre feet) 0
% Full
26 .1 1
3830.12
000
I 59.0% I I) Oceano su pplied S tate Water to Canyon Crest via Arroyo Grande's Edna turn out. A to tal
of I .I AF delivered to Canyon C,-est was added lo Oceano's State Wa ter u sage this month
and 1.1 AF was subtracted from Arroyo Grande's usage this mon th_
Friday, April 5, 2019 Daia eniered by : D. Bravo Report prinied by: Admin Page 1 of 1
Total Water
De6nri,s
This Alonth
114 . ..l I
30 .6
66 .75
98.5
8.35
7 .77
336.3 -i
11
Supply Summary
Item 11.c. - Page 13
4 0000.0
35000.0
30000.0
.2.5000.0
15000.0
!1.0000.0
5000.0
0.0
LOPEZ RESERVO IR. STORAG E PROJIIE CT IION
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L St.o ra g:e proj e ction is bas,ed o n pre d ict e d ra infa l l from longr angeweat h e r.oom ,
hi sto r ic inflow b ase d on pre d ict e d r ai nfa ll, 18 -]'9 downstr ea m r,e lease r e qu es t s, and
mun icipa l usag,e ..
0.~9
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12 Item 11.c. - Page 14
Lopez Water -Surplus Water Availabl e in 2019/2 0 20 by Contract
A B C D
2018 -2019 Water Available Per Contract
Total
Contractor Entitl ement Surpl us 2 Available
A r royo Grande 2 ,290 564 2,854
Pismo Beac h 1 892 220 1,112
Grover Beac h 800 197 997
Ocea no CSD 303 75 378
CSA.12 245 60 305
Sub Totals 4,530 1,116 5,646
Downstream 4,200
Total 8,730
NOT ES
L Includ es subcont ract for 92 AF from CSA12
2. Surplu s wat e r as d eclared 011 5 /15/2018 at BOS
CALCULATIONS
Co lums A-D from BOS 5 .. 15.2018 Surplus Wat er Dedaratio n
Co lumns IE -H act ual and proj ect ed water d e 1 · eri es for wat e r yea r 1 8/19
Co lumns 11-J su r p lu s wat e r ca lcu lat io ns pe r Wat er Supp ly Co nt ract s
Surp lus Ava i lab l e
Total Su rtp lus by Cost of
Contractor p ercent of Entitlement Cost per AF surplus Water
A r royo Grande 378 $ 36.36 $ 13,728 .01
Pismo Beac h 147 $ 36.36 $ 5,34 7.27
Grover Beac h 132 $ 36.36 $ 4,795.98
Ocea no CSD 50 $ 36.36 $ 1,816.82
CSA.12 40 $ 36.36 $ 1,469.21
Total 747 $ 27,157.28
f F I )
Actual Deliveries Surp l us by Contract
Apri l 2018-Mar 2019
Surplus
Generated Surplus
Unused Availab lle
Entitlement Surpl us Entitlement by Contra.cl
2,084 0 20 6 378
892 220 0 147
80 0 9 0 132
30 3 75 0 50
74 0 171 40
4,153 377 747
3,830 370 0
7,983 747 747
13 Item 11.c. - Page 15
20
-___ Deep Well Index Level
(Wells -24B03 , -30F03 a n.d -30N02) I -I " I I ' I
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!H ISTORI CAL SECOND QUARTER DEEP WELL INDEX LEVELS
Northern Ciities lrVlanagement Area
2010 201 5 2020 ,..
s
San L uis Ob ispo County, Ca lifornia Water Solutions., Inc.
14 Item 11.c. - Page 16
Monthly Water Use Comparison
160
144.2
140
130.4
120
100
86
80 78
60
40
20
0
Mar-18 Mar-19
■ Acre Feet ■ Usage (gpcd)