Water Resources - IMPACT - September 2017 - 10

may be in the early stages of investigation
or have recently drilled wells. Why they
are not active is important, as I laid out in
Bloetscher et al. (2014, 2015) and American
Water Works Association (AWWA)
(2016). We are still learning about ASR. In
certain formations, it works well; others
are more of a challenge. Most of the sites
have been constructed in limestone and
alluvial formations. Confinement and the
transmissivity of the aquifer are relevant
to storage. Challenges to ASR systems
include permitting issues, geochemical
problems, geological constraints, clogging,
disinfection byproducts and water rights
issues. The inability to recover sufficient
quantities of injected water was listed as a
reason to inactivate ASR efforts at 20 sites,
while recovery of metals or arsenic was an
issue at a dozen more.
Saltwater systems are a particular
challenge. Where a brackish aquifer is
used, the density difference between the
treated freshwater and saline source causes
a "bubble" of freshwater to form. When
injection starts, buoyancy occurs whereby
the freshwater wants to float on top of the
brackish water, but there is also mixing of
the native and injected water. The mixing
creates a transition zone between the
native and injected water. The quantity
of water to be stored can be as extensive
as the localized aquifer system allows,
and can be continuously pumped into the
aquifer system until needed. However, the
initially mixed water may not be recoverable
unless treatment is deployed to remove
impurities such as elevated levels of chloride
(salinity). The Collier-Manatee well in
Florida demonstrated that in a 40 foot-thick
formation, we were able to displace the water
during injection. However 6 months later,
buoyancy stratified the layer - the bottom
20 feet had chloride much like the native
water. This is because vortex theory indicates
that the freshwater will ultimately flatten out
- the higher transmissivity, the faster it will
spread out. In such systems, a large mixing
area forms. Depending on the formation,
given adequate quantities of injected water
and the right aquifer properties, the bubble
would remain fresh for a sufficiently long
time period to be available for water supply
augmentation (see Figure 2).
But here is what we do know: most sites
inject about 1 MGD (million gallons per
day), and withdraw about the same amount.

10 * Water Resources IMPACT

September 2017

10
9
8
7
6
5
4
3
2
1
0
Oct-00

Jan-01

Apr-01

Demand (MGD)

Jul-01

Nov-01

Feb-02

May-02

Raw water (MGD)

Sep-02

Dec-02

Mar-03

ASR Needed (MGD)

Figure 2: Comparison of Demand vs Supply. ASR is augmenting 4 months per year.

Injecting huge volumes of water have been
less common. There are sites with over a
billion gallons stored, but they have been
in existence for many years. Potable water
can often be pumped into the distribution
system with only disinfection, but pH and
oxidation-reduction adjustments are needed
in some cases. The recovered ASR water is
combined with the raw water to the influent
of the water plant, and treated. In most cases
these waters are surface waters. Changes
in water quality can occur during storage.
Reclaimed water is used to supplement
irrigation systems - mostly in Florida
and Arizona.
One big issue facing ASR today is
ownership of the water injected. Several
western states do not have rules with respect
to groundwater and recovery. Without
being able to recover the water, there is a
disincentive to pursue ASR. Disinfection
byproduct concerns have been raised in a
couple of states. Chlorination is needed to
prevent biofouling in the wells but it can
create disinfection byproducts. However,
25-year-old Pyne et al (1995), an AWWA
Research Foundation report on disinfection
byproducts in ASR wells, indicated they
dissipated with time. Organics will do
this as no aquifer is bacteria-free and the
bacteria consume the organics.
But perhaps the biggest challenge to ASR
is client expectations. It takes time to study
and understand the aquifer dynamics. Many
tests, lots of samples and lots of injection of
water are required. Multiple cycle tests are
needed to identify how much water can be
stored and how long it can be stored. ASR
is not useful if the water moves away in 60

days. Waters are needed 180, or 540 days
later. For ASR to be useful, the water needs
to be there for a long time. Making clients
understand the need to test for five years,
and spend thousands on the program are
important. Otherwise potentially successful
ASR projects will not be pursued further.
Aquifer storage and recovery has been
demonstrated to work in many locations.
However it takes time. To be able to quantify
the potential for success, a plan must be put
in place and pursued. Clients must fund it,
and have patience. Tests will not always go
as planned. That is the real challenge
for ASR. ■
Frederick Bloetscher is a professor at Florida
Atlantic University in Boca Raton, Florida, and
also the president of Public Utility Management
and Planning Services, Inc., which he started in
2000. His interests focus on the planning and
management water resource systems, including
groundwater resource and risk projects. Prior
to starting his own firm, he worked for local
governments in utility management for 20
years. Contact: fbloetsc@fau.edu.

References

1. Manual M-63 - Aquifer Storage and Recovery 1st
edition (2015), primary author and editor, American Water
Works Association, Denver, CO.
2. Bloetscher, F.; Sham, Chi Ho, Ratick, S. and Danko
III, J.J. 2015. Status of Aquifer Storage and Recovery in the
United States - 2013, British Journal of Science 70 April
2015, Vol. 12 (2).
3. Bloetscher, F.; Sham, C.H.; Danko, J.J.; and Ratick, S.
2014, Lessons Learned from Aquifer Storage and Recovery
(ASR) Systems in the United States, Journal of Water
Research, 2014, 6, 1603-1629. http://www.scirp.org/journal/
jwarp http://dx.doi.org/10.4236/jwarp.2014.617146
4. Pyne, R. D. G.; Singer, P.C.; and Miller, C.T. (1995),
Aquifer Storage Recovery of Treated Drinking Water,
AWWA Research Foundation, Denver, CO.


http://www.scirp.org/journal/ http://dx.doi.org/10.4236/jwarp.2014.617146

Table of Contents for the Digital Edition of Water Resources - IMPACT - September 2017

President’s Message
Growing Up…with Managed Aquifer Recharge
Aquifer Storage and Recovery as Means to
The Regulatory Environment of Managed
The ASCE-EWRI Standard Guidelines
Managed Aquifer Recharge:
Managed Aquifer Recharge: A Global Perspective
What’s Up with Water? Sisyphus, Heraclitus and WOTUS
The New Economics of Water: Reducing CO2 Emissions in the Bay Delta Could Reverse Erosion
Domestic Well Aquifer Storage and Recovery Using Seasonal Springs
Philosophy and Ethics: The Rio Grande and the Ganges Rivers: How Human ‘Success’ is Choking the Life out of Two Great River-Spirits
ASR: Aquifer Storage Rescues a Small Water Supply District
Putting Aquifers to Work: MAR Applications in Nutrient Removal
Summer Conference Recap
Harvesting Glacial Meltwater with Managed Aquifer Recharge
AWRA State Section and Student Chapter News
In Memoriam: Peter E. Black
Herbert Scholarship Award Recipients for 2017-2018 Announced
August JAWRA Highlights
2017-2018 Editorial Calendar
Water Resources - IMPACT - September 2017 - intro
Water Resources - IMPACT - September 2017 - cover1
Water Resources - IMPACT - September 2017 - cover2
Water Resources - IMPACT - September 2017 - 3
Water Resources - IMPACT - September 2017 - 4
Water Resources - IMPACT - September 2017 - President’s Message
Water Resources - IMPACT - September 2017 - Growing Up…with Managed Aquifer Recharge
Water Resources - IMPACT - September 2017 - 7
Water Resources - IMPACT - September 2017 - Aquifer Storage and Recovery as Means to
Water Resources - IMPACT - September 2017 - 9
Water Resources - IMPACT - September 2017 - 10
Water Resources - IMPACT - September 2017 - The Regulatory Environment of Managed
Water Resources - IMPACT - September 2017 - 12
Water Resources - IMPACT - September 2017 - 13
Water Resources - IMPACT - September 2017 - The ASCE-EWRI Standard Guidelines
Water Resources - IMPACT - September 2017 - 15
Water Resources - IMPACT - September 2017 - 16
Water Resources - IMPACT - September 2017 - Managed Aquifer Recharge:
Water Resources - IMPACT - September 2017 - 18
Water Resources - IMPACT - September 2017 - 19
Water Resources - IMPACT - September 2017 - Managed Aquifer Recharge: A Global Perspective
Water Resources - IMPACT - September 2017 - 21
Water Resources - IMPACT - September 2017 - 22
Water Resources - IMPACT - September 2017 - 23
Water Resources - IMPACT - September 2017 - 24
Water Resources - IMPACT - September 2017 - 25
Water Resources - IMPACT - September 2017 - 26
Water Resources - IMPACT - September 2017 - 27
Water Resources - IMPACT - September 2017 - 28
Water Resources - IMPACT - September 2017 - 29
Water Resources - IMPACT - September 2017 - What’s Up with Water? Sisyphus, Heraclitus and WOTUS
Water Resources - IMPACT - September 2017 - 31
Water Resources - IMPACT - September 2017 - The New Economics of Water: Reducing CO2 Emissions in the Bay Delta Could Reverse Erosion
Water Resources - IMPACT - September 2017 - Philosophy and Ethics: The Rio Grande and the Ganges Rivers: How Human ‘Success’ is Choking the Life out of Two Great River-Spirits
Water Resources - IMPACT - September 2017 - ASR: Aquifer Storage Rescues a Small Water Supply District
Water Resources - IMPACT - September 2017 - 35
Water Resources - IMPACT - September 2017 - Summer Conference Recap
Water Resources - IMPACT - September 2017 - 37
Water Resources - IMPACT - September 2017 - AWRA State Section and Student Chapter News
Water Resources - IMPACT - September 2017 - In Memoriam: Peter E. Black
Water Resources - IMPACT - September 2017 - Herbert Scholarship Award Recipients for 2017-2018 Announced
Water Resources - IMPACT - September 2017 - 41
Water Resources - IMPACT - September 2017 - 2017-2018 Editorial Calendar
Water Resources - IMPACT - September 2017 - cover3
Water Resources - IMPACT - September 2017 - cover4
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