Energy Savings Effects of Artificial Recharge and Increased Storage in Groundwater Basins San Antonio Creek Spreading Grounds Rehabilitation Project Jordan L. N. Kear, P.G., C.Hg. First Western Forum on Energy & Water Sustainability UCSB Bren School 23 March 2007
Daniel B. Stephens & Associates, Inc.
Acknowledgements
Golden State Water Company Ojai Basin Groundwater Management Agency Watersheds Coalition of Ventura County Ventura County Watershed Protection District State of California Department of Water Resources Casitas Municipal Water District Senior Canyon Mutual Water Company Ojai Water Conservation District
Daniel B. Stephens & Associates, Inc.
Conceptual Workplan Number “two” project included in WCVC Proposition 50 Grant Application
Rehabilitate abandoned spreading grounds Repair and reconstruct intake structure and diversion Drill depth-discrete monitoring well Construct recharge wells Operation and maintenance CEQA compliance
Daniel B. Stephens & Associates, Inc.
SACSGRP Provides for optimization of project during final design Staged approach-some investigation precedes groundbreaking and final design Fill data gaps Depth discrete monitoring wells, recharge wells, aquifer testing Incorporate findings into spreading ground efforts Provides costs thought to be conservative “Blessed” by SWRCB with $$$$$$$$$
Daniel B. Stephens & Associates, Inc.
Demonstration of Benefits How much water is available? Hydrologic Assessment
How do stakeholders benefit? Numerous facets... ENERGY SAVINGS – Solar energy effectively lifts water up into the watershed; this potential energy is retained by such a project, thus decreasing the electrical demand to meet local dynamic head requirements Daniel B. Stephens & Associates, Inc.
Benefits Discussion
Added water in storage over natural conditions Higher water levels Improved water quality Higher production rates from FFD pumps More efficient energy use Less sanding from wells Longer pump life Longer well life Less “cascading water” conditions in wells Daniel B. Stephens & Associates, Inc.
Benefits Discussion
Longer discharge to stream for habitat amelioration Partial Lake Matilija source replacement Local use of local resource Decreased demand from Lake Casitas locally per capita Less likely importation necessity (State Water Project)
Daniel B. Stephens & Associates, Inc.
Hydrologic Assessment Based on 50+ years of hydrologic records Uses a “top-down” approach resulting in higher average spreading quantities (914 AF/yr): local input-output based, GC/SC Uses a “bottom-up” approach resulting in lower average spreading quantities (308 AF/yr): SAC confluence and area-based Reviewed – DBS&A, VCWPD, H&P Daniel B. Stephens & Associates, Inc.
From available stream water... Ranges of potentially spread water is less: about ~5 cfs for fish passage (assumed to be adequate based on literature, needs regulatory concurrence) at point of compliance = 10.65 cfs at GC/SC confluence capacity of structures: diversion, intake infiltration capacity of grounds infiltration capacity of recharge wells amount of storage in basin
Daniel B. Stephens & Associates, Inc.
Daniel B. Stephens & Associates, Inc.
5D3(341) Daniel B. Stephens & Associates, Inc.
January 11, 1984
Daniel B. Stephens & Associates, Inc.
Daniel B. Stephens & Associates, Inc.
Rain Gauge Location: 34.4480 N 119.2300 W
Rain Gauge Elevation: 745 ft (227 m) above mean sea level
50 45 40 35 30 25 20 15 10 5 0
Calendar Year
Daniel B. Stephens & Associates, Inc.
150 100 50 0
-50 -100 -150 -200 -250
Year
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Daniel B. Stephens & Associates, Inc.
Daniel B. Stephens & Associates, Inc.
1950-2006 56-year period of record for hydrologic assessment Conservative estimates of contributions to groundwater basin is 308 AF/yr on average Roughly equal to one foot of basin-wide increase in static water levels 200 wells with commensurate decreased electricity demand Daniel B. Stephens & Associates, Inc.
SAC SG RP Benefits 10000
0
20
40 1000
100 100
120 10 140
160
180
Spread Water (AF)
Daniel B. Stephens & Associates, Inc.
DTW (ft)
DTW w/ spreading (ft)
2001
1998
1994
1991
1988
1984
1981
1978
1974
1971
1965
1961
1956
1953
1952
1
Depth to water (ft)
80
1949
Acre feet spread
60
Cumulative benefit Akin to saving for retirement during one’s most productive years Longer drought periods see effect 1965: 43 feet of higher water levels over historic 1978: 3 feet of improvement 1990: 7 feet
56-year benefit: Averages 14.2 feet of increase Daniel B. Stephens & Associates, Inc.
Subsurface Energy Factors
Daniel B. Stephens & Associates, Inc.
Typical Ojai Well Values
7,500 AF pumped from the basin Well efficiency 25 to 70 % Specific Capacity 10 to 70 gpm/ft drawdown Deep Well Turbine pumps typical Overall plant efficiency rates... 40% (inefficient) to (efficient) 68% Occasional “Edison Tests” – Hydraulic testing of well pumps
Daniel B. Stephens & Associates, Inc.
1992 Historic
With Spreading
Discharge Pressure (PSI)
38.7
38.7
Standing Water Level (ft)
149.2
135
3.4
3.4
89.4
89.4
152.6
138.4
Total Head (ft)
242
227.8
Capacity (GPM)
226
226
GPM per foot drawdown
66.47059
66.47059
AF pumped in 24 hours
0.998674
0.998674
kW input to motor
24.4
23
HP input to motor
32.7
30.7
90
90
586.3558
552.7124
42.2
42.2
Drawdown (ft) Discharge Head (ft) Pumping water level (ft)
Motor Load (%) kWh per AF Overall Plant efficiency (%) Daniel B. Stephens & Associates, Inc.
Focus on the energy Pumping lift energy is effectively replaced by solar energy in the form of evaporation lift to heights within the watershed Net benefit per (inefficient) well = 33 kWh per acre foot pumped Over 7,500 Acre feet pumped = 250 MWh average annual savings Daniel B. Stephens & Associates, Inc.
250 MWh.... Powers 420 homes for a month Powers 35 homes for one year Small, but significant energy savings Recognized by Grant Funding authorities as a benefit of the project Increased well efficiency can also reduce energy demands for pumping groundwater Daniel B. Stephens & Associates, Inc.
Daniel B. Stephens & Associates, Inc.
