Western Water Workshop Front Range Groundwater: Scarcity and Opportunity July 21, 2010 Topics for Presentation What problem? The inevitability of groundwater dependence Conservation as an answer A portfolio approach Infrastructure Where.
Download
Report
Transcript Western Water Workshop Front Range Groundwater: Scarcity and Opportunity July 21, 2010 Topics for Presentation What problem? The inevitability of groundwater dependence Conservation as an answer A portfolio approach Infrastructure Where.
Western Water Workshop
Front Range
Groundwater: Scarcity
and Opportunity
July 21, 2010
Topics for Presentation
What problem?
The inevitability of groundwater
dependence
Conservation as an answer
A portfolio approach
Infrastructure
Where to next?
Storage for future use
The public policy dilemma
Why Groundwater?
Woodmoor’s Raw Water System Development
Historical Perspective
• Why non-tributary groundwater?
– No accessible surface water provider
– Readily available
– Valuable resource
– Develop incrementally
– Relatively low cost for initial development
– Protected from contamination
– Drought resistant
• Groundwater is not “running out” but will cost more as
groundwater levels continue to decline
• More wells, more energy needed to pump at deeper levels,
reduction in well yield, and higher maintenance costs
Denver Basin Aquifers
•Interbedded Sandstone, Shale and Clay Aquifers
Source: USGS HA-730-C
Dawson: 50 – 150 gpm
700 ft total depth
Denver: 50 – 250 gpm
1300 ft TD
Arapahoe: 200 – 500 gpm
1900 ft TD
Laramie-Fox Hills: 75 – 150 gpm
(projection) 2500 ft TD
Groundwater
dependent
communities
on the Front
Range
All Rights Reserved © West Water Research
Confidential and Proprietary Information
What Problem?
100 year
theoretical
life of the
aquifer
The
practical life
is 30 to 40
years
Source: Colorado Foundation for Water Education
NEIGHBORHOOD DRAWDOWN
DWSD 8
Some simple math
A single family home needs about one-half
acre-foot of delivery
The aquifer (all 4 layers) holds about 1.5
acre-feet of water per acre
Land density is about 3.5 units per acre.
At build-out, the water needed is 1.65 acrefeet per acre USING ALL 4 AQUIFERS!
Demand vs. Supply
Service Area Build-out
EFFECTS OF GROWTH
DWSD 9
FULL GROWTH
DWSD 10
Arkansas Basin Consumptive
Use Water Needs Assessment
KEY FINDINGS
Total Gross Gap:
28,600 – 28,752 AF
Counties with largest gap:
El
Paso (unincorporated): 22,600 AF
Increased
demand: 9,250 AF
Loss of existing groundwater
supplies: 13,350 AF
Lake:
1,950 AF
Increased
demand- Unincorporated
areas
Arkansas Basin Roundtable
Conservation
Seasonal variation and daily peak
A water manager has to meet both
Peaking on a deep aquifer well stresses the
aquifer further reducing well yield
Residential Water Use
Other
4%
Outdoor
40%
Leaks
8%
Toilet
15%
Faucet
9%
Shower & Bath
11%
Washer
13%
2005 Annual Hydrograph
60.0
Outdoor
66.45%
Monthly Demand (Million Gallons)
Indoor
62.28%
50.0
56.74%
56.36%
40.0
47.95%
Irrigation / Summer Demand
30.0
25.03%
14.33%
20.0
Indoor / Winter Demand
10.0
0.0
Jan
Feb
Mar
Apr
May
Jun
Jul
Month
Aug
Sep
Oct
Nov
Dec
Time
11:00 PM
10:00 PM
9:00 PM
8:00 PM
7:00 PM
6:00 PM
5:00 PM
4:00 PM
3:00 PM
2:00 PM
1:00 PM
12:00 PM
11:00 AM
10:00 AM
9:00 AM
5
8:00 AM
7:00 AM
6:00 AM
5:00 AM
4:00 AM
3:00 AM
2:00 AM
1:00 AM
12:00 AM
Demand (MGD)
Managed Peak Day Demand
6
20% - Peak Reduction
4
3
2
1
0
Conservation/Demand Management Programs
Passive Conservation
• Information/Education
–
–
–
–
–
–
Bill Stuffers
Articles
Water-Wise Garden Open House
New “Product” Exhibit
“Green Builders” BMPs
Water Use Audit Programs
• Demand Reduction
– Annual Demands 5 % - 10%
– Max Day Demands 5 % – 10%
Conservation/Demand Management Programs
Active Demand Management
–
–
–
–
–
–
–
Reduction of Unaccounted for Water
Rebates
Designated Watering Days (max-day)
Designated Watering Hours (annual demand)
Budget Billing
Conservation Rates
“Water Conservation” Building Codes
• Demand Reduction
– Annual Demand 10% - 15%
– Max Day Demand 15% - 25%
Conservation/Demand Management Programs
Restrictions
– Turf Limitations – size – type
– Punitive price/rates structures
– Landscape Designs Review and Approval
– Irrigation System Review and Approval
– Limit Designated Watering Days (max-day)
– Limit Designated Watering Hours (annual demand)
– Budget Billing – reduce budgets – increase rates
• Demand Reduction
– Annual Demands 15% - 35%
– Max Day Demands 25% - 40%
2007 Summer Water Use Program
(June 1st. through September 1st.)
Common Elements
• Outdoor Use Calendar
– Odd # address Sunday, Wednesday, Friday
– Even # address Saturday, Tuesday, Thursday
– NO watering on Monday
• Prohibited Watering Hours
– No Watering 10 am to 6 pm
• Water Waste
– It is a violation to waste water by causing runoff of water
on streets or into drainage facilities
2007 Summer Water Use Program
(June 1st. through September 1st.)
Outdoor Watering & Irrigation
• Turf Grass
– 3 times per week per calendar
• New Seed & Sod
– Lawn permits from District - additional irrigation times allowed - 2
week permit for sod - 4 week permit for seed
• Flowers, Vegetables, Trees and Shrubs
– Hand-held hose or low-volume non-spray irrigation, any day, any
time.
• Designated Community Parks, open space and Athletic
& playing fields
– Water Budget developed with the District
A Portfolio Approach
Conservation is fundamental
Do you issue a new tap on conserved water?
Demand Harding
The Yuck Factor
Indirect Potable Reuse
The Space Shuttle model
Groundwater remains in the portfolio
Integrated Supply Strategy
Groundwater
Exchange
Conservation
Exchange
D
E
M
A
N
D
Surface
Water
Conserve.
Surface
Water
Groundwater
Exchange
Groundwater
Current
Current
Future
Future
Infrastructure
Delivery infrastructure is expensive
The remaining sources are not where the
customers are located
Is this speculation?
Acquire Water Right
Infrastructure
Development
Sell Water
Wholesale
Infrastructure Development:
Well Field
The wells will be grouped into pods and
developed in phases to minimize up front capital
costs.
The development of the well field includes down
hole drilling, power hook up and collection piping.
The well field will include between 20 and 35
wells drilled at depths of 1,500 to 2,800 feet.
There is a substation on the southeast side of the
ranch reducing the costs of power hook up.
A collection network of 8” – 20” pipe will be
constructed over a phased period as market
demand comes on line.
Pump station and electrical transmission
infrastructure development costs are included in
the well field development costs.
Estimated net present value of the well field
development costs range from $29 million to $41
million based upon sales scenario.
All Rights Reserved © West Water Research
Confidential and Proprietary Information
Acquire Water Right
Infrastructure
Development
Sell Water
Wholesale
Infrastructure Development:
Conveyance (cont.)
Brown and Caldwell has prepared initial pipeline
route and cost estimates.
The routes and pipe size were selected based upon
the four most likely demand scenarios.
The pipeline route heading south consists of 9 miles
of 16” to 24” inch diameter pipe.
The pipeline routes heading north consist of 12 to 26
miles of 16” to 24” inch diameter pipe.
Pressure reducing facilities and pump station costs
are included in conveyance cost estimates.
Estimated net present value of the conveyance costs
range from $23 million to $45 million based upon
sales scenario.
All Rights Reserved © West Water Research
Confidential and Proprietary Information
Groundwater Dependence
The
Denver
Basin
Aquifers
Rate of
depletion
Future
sources
of
supply?
The Denver Basin
USGS Study: 2008
Groundwater Dependence
Designated
Basins
A Modified Prior
Appropriation
Doctrine
(Groundwater Act
of 1965)
Management
Districts
Source: Division of Water Resources
2007:A Two Pronged Approach
Base study of the Upper Black Squirrel
Designated Groundwater Basin
Colorado Geologic Survey, Dec, 2008
A Public Policy Forum sponsored by the
Arkansas Basin Roundtable (Sept, 2007)
Peer Review by the Director of Natural
Resources, Dec, 2008
Alluvial
aquifer
east of
Colorado
Springs
Lying
atop a
bedrock
layer of
Pierre
shale
Depletion
began in
the 1960’s
1964 to 2004
well
depletions
Designated Groundwater
Upper Black Squirrel Creek Basin
Alluvium Storage Calculations
*
Using a storage coefficient of 0.18
Description
Total Area (acres)
Total Storage Capacity (ac-ft)
Total Saturated Primary Alluvium
78,850
474,643
Total Unsaturated Primary Alluvium
78,850
605,865
-
Unsaturated Alluvium (50ft-water table)
38,000
218,327
-
Unsaturated Alluvium (75ft-water table)
20,250
88,164
-
Unsaturated Alluvium (100ft-water table)
8,540
25,996
Conference in Sept, 2007
http://ibcc.state.
co.us/News/
Conflicting Conclusions
The legal
system is
working just
fine
One at a time
legal cases are
very expensive
Recharge for Future Use
Recharge as
augmentation
is not recharge
for future
storage
Rules in the
Denver Basin
by SEO
A National Issue
National
Academy of
Sciences MUS
study
EPA Experts
Meeting May
5-6, 2009
Where do we go from here?
How do quantity and quality
work together?
How will the State permit
projects?
A pilot by the General Assembly?
Where do we go from here?
Source: DNR Director Harris Sherman, Dec, 2008
Opportunity?
Can we collaborate before we reach a crisis?
Can the Prior Appropriation Doctrine
accommodate the future of Colorado’s water
resources?
The River of 1890
Groundwater is tributary until you prove a
negative, i.e. non-injury
Is the legislature the appropriate venue to
change groundwater policy?