water

1. Benefits: [E = Effectiveness, I = Environmental Impact, P = Practicability]
E Provides an extra 4700 AFY most years, over 3 times SqCWD’s 1500 AFY target
E Recharges aquifers 2 to 3 times faster: Purisima in as little as 7 years,
Santa Margarita in as little as 4 years
E Fills a vast water bank 5x bigger than the Loch and 30x bigger than SqCWD’s
1500 AF target.
E Protects all of mid-County against long-term droughts.
E Gives good yield even in most dry years, because winter storm water usually is
still abundant.
I Increases fish populations: cool water seeps from recharged aquifers into habitat
base flows.
I Increases dry-season flows at Tait Street Diversion, easier to meet bypass
requirements.
I Uses water which is not needed by fish habitat; reduces big turbid flows that may
harm fish.
IP Fisheries’ approvals may be quick as a result, speeding water rights approval.
I Good carbon footprint: Energy use per gallon is only about the same as SCWD’s
is today.
EIP Hydroelectricity can be generated in the gravity feed to customers. (see Section
15 for details)
EP When river is turbid, allows GHWTP to draw water while Loch is being filled.
P Operating cost per gallon is comparable to SCWD’s current operating cost per
gallon.
P Low capital cost per AF of capacity, potentially 6 times lower than that of desal
plant.
P High yield on capital cost, because of long project operating lifetime. Potential
profit on pond.
Summary: Increase Felton diversions and pre-treat water to a standard suitable for
storage in Loch Lomond. Increase Loch pipeline capacity to about 28 mgd by upgrading
existing aging 14 mgd pipeline and adding a second one. Quarry storage of stormwater
surges probably will be unnecessary. Transfer to Felton some of the County’s reserved
17,000 AFY Zayante Creek water right and/or obtain San Lorenzo River stormwater
rights at Felton Diversion.

2. Build an 8 mgd
conventional water
treatment plant to
treat Loch water all
year for the benefit of
SqCWD, SCWD,
SVWD and other
water districts--which
would rest their wells
substantially and thus
let all of the region’s
aquifers recharge at
the highest possible
rates. Locate the
treatment plant at
about the same
elevation as the Loch
so getting water from
the Loch takes little
energy, and so most
customers can be fed
via gravity only,
without needing
electric pumps. Such
a good site for the
plant might be in the
Scotts Valley area,
perhaps in a corner
of one of the quarry
properties.
For water diversions use Ranney collectors predominantly, as they filter out most
turbidity before it even enters their system, and because they are very friendly to fish.
(See Section 12 for details) To pre-treat conventional (non-Ranney) Felton diversions
for turbidity, build a low-cost settling pond nearby using large drain pipes to define its
periphery and provide floodwater bypass routes. (See Section 11 for details.) Years
later when sediment has filled it up and aquifers are recharged, sell it as buildable land.
(At that point, most of the Ranney collectors could be rested as well, except in drought-recovery
years.)
Background:
Of the 190,000 AFY which flows through the streams of SCWD and SqCWD, only some
11,000 AFY (6%) is diverted (all by SCWD). The other 94% flows into the ocean
unused.1 The Lochquifer Alternative simply would divert an extra 5400 AFY each winter
and would save it in Loch Lomond. The Loch has a capacity of 8400 AF2, quite ample
for the job. In the past the Loch has been drawn to as low as 28%, and has been at or
below the 36% level five times in the last 41 years, as shown by the chart below.3
_______________________
1 The amounts of water diverted by upstream communities are negligible here, because
the amounts are small and because irrigation and septic systems return much of these
amounts via underground pathways.

3. 2 SCWD 2010 Urban Water Management Plan (UWMP) Sec. 3.1.3
3 Chart from the SCWD2 Seawater Desalination Draft Environmental Impact Report
(dEIR):
Although SCWD can resort to its bountiful streams, SqCWD is entirely dependent on
wells presently. Scotts Valley Water District (SVWD) is heavily dependent upon wells,
which draw from the Santa Margarita Aquifer which extends into the San Lorenzo River
valley. SCWD’s Loch Lomond reservoir currently is doing double-duty as mitigator of
both the “long-term drought” problem (once in 6.5 years average) and the “short-term”
a.k.a. “winter/summer” problem: it rains lots in the winter but almost not at all in the
summer—and summer demand is twice that of winter. The Lochquifer Alternative would
relieve the Loch of double-duty so as to recharge the Purisima, Santa Margarita and
Lompico Aquifers at virtually the fastest possible rates.
The long-term drought problem is caused by an extremely high variability in rainfall year-to-
year, per SCWD’s Confluence computer model. A comparison of 71 years of data
about San Lorenzo River flow reveals that flow in the wettest year exceeded flow in the
driest year by 29 times. (See Section 5 for a graph and details regarding weather
variability and stream flow magnitudes.)

4. Flows
Into
the
Loch
Source:
Water
Supply
Alternatives
Study
Camp
Dresser
&
McKee
January
1994
1
mgy
=
3.07
AFY.
From
the
above
graph:
(thousand
mgy)
from
(thousand
AFY)
from
Year
Newell
Creek
Felton
Diversion
Total
Year
Newell
Creek
Felton
Diversion
Total
1970
2.7
0.7
3.4
1970
8.3
2.1
10.4
1971
0.5
1.0
1.5
1971
1.5
3.1
4.6
1972
0.4
0.8
1.2
1972
1.2
2.5
3.7
1973
3.2
0.6
3.8
1973
9.8
1.8
11.7
1974
2.1
0.9
3.0
1974
6.4
2.8
9.2
1975
1.4
0.8
2.2
1975
4.3
2.5
6.8
1976
0.2
0.1
0.3
1976
0.6
0.3
0.9
1977
0.2
0.1
0.3
1977
0.6
0.3
0.9
1978
3.5
0.7
4.2
1978
10.7
2.1
12.9
1979
1.2
0.7
1.9
1979
3.7
2.1
5.8
1980
2.4
0.8
3.2
1980
7.4
2.5
9.8
1981
0.8
0.8
1.6
1981
2.5
2.5
4.9
1982
4.2
0.5
4.7
1982
12.9
1.5
14.4
1983
7.1
0.5
7.6
1983
21.8
1.5
23.3
1984
0.7
1.0
1.7
1984
2.1
3.1
5.2
1985
0.4
1.0
1.4
1985
1.2
3.1
4.3
1986
4.5
0.6
5.1
1986
13.8
1.8
15.7
1987
0.4
0.5
0.9
1987
1.2
1.5
2.8
1988
0.3
0.2
0.5
1988
0.9
0.6
1.5
1989
0.4
0.5
0.9
1989
1.2
1.5
2.8
1990
0.2
0.2
0.4
1990
0.6
0.6
1.2
1991
0.8
0.4
1.2
1991
2.5
1.2
3.7
1992
1.8
0.8
2.6
1992
5.5
2.5
8.0

5. Total
39.4
14.2
53.6
Total
121.0
43.6
164.6
Average
1.713
0.617
2.330
Average
5.259
1.895
7.154
Median
2.25
0.75
3.00
Median
6.91
2.30
9.21
Note:
numbers
in
yellow
exceed
the
8400
AF
capacity
of
the
Loch;
nevertheless,
water
was
added
from
Felton.
Why
are
medians
higher
than
means?
EP
PROPOSED
ANNUAL
LOCHQUIFER
WATER
BALANCE
SHEET
for
the
Lochquifer
Alternative
in
an
Average
Year,
stated
in
acre-­‐feet
per
year
(AFY)
INFLOWS
AFY
Source
Comments
1932
Rain
from
9
sq.
mi.
watershed
above
Loch;
previous
chart
(Camp)
says
this
=
5259
avg.
6000
Diversions
from
San
Lorenzo
River
at
Felton
and
from
Zayante
Creek;
this
is
the
proposed
maximum
rate
of
diversion,
not
the
increase
in
the
rate
over
the
historical
rate.
7932
TOTAL
5600
of
this
goes
into
Loch;
the
balance
of
2332
of
this
goes
to
water
districts
when
diverted
in
the
wet
third
of
the
year
OUTFLOWS
AFY
Destination
Comments
2332
WDs;
wet
goes
directly
to
water
districts
when
diverted
in
the
wet
third
of
the
year;
its
purpose
is
to
rest
wells,
to
let
aquifers
recharge
quickly.
3494
WDs;
dry
goes
from
Loch
to
water
districts,
mostly
in
the
dry
2/3
of
the
year;
its
purpose
is
also
to
rest
wells,
to
let
aquifers
recharge
quickly.
5826
AFY
is
the
total
amount
provided
to
WDs
for
resting
wells.*
675
Evap.
The
Loch
typically
loses
some
675
AFY
to
evaporation.
0
SLVWD
San
Lorenzo
Valley
Water
District
has
not
been
exercizing
their
320
AFY
right,but
may
begin
to
do
so
as
a
matter
of
degree
sometime
in
the
future.
145
Newell
Cr.
Fisheries
regulators
rules
require
0.2
CFS
to
be
let
out
of
the
Loch
at
all
times;this
may
be
increased
to
1.0
CFS,
where
it
has
been
historically.
1286
SCWD
Santa
Cruz
Water
Department's
approximate
annual
average
Loch
water
use
7932
TOTAL
5600
AFY
is
the
total
amount
coming
from
the
Loch;
it
is
the
sum
of
all
Outflows
items
with
the
exception
of
the
first
item.
This
number
was
chosen
so
that
a
full
Loch
would
be
drawn
down
to
a
level
no
lower
than
1/3
of
capacity.
*
The
approximate
amounts
of
new
water
which
would
be
required
to
rest
wells
completely:
4100
SqCWD
1400
SVWD
450
SCWD
5950
TOTAL

6. EP
NOTE:
Even
in
most
dry
years,
WDs
do
NOT
need
to
“repay”
SCWD
with
their
aquifer
water:
• SCWD
will
merely
use
a
larger
share
from
the
Loch
via
the
new
treatment
plant,
and
• the
rested
wells
will
resume
pumping
somewhat,
but
for
their
own
respective
WDs
only.
In
general,
actually
taking
more
water
out
of
the
aquifers
than
we
do
now
is
an
occurrence
which
would
happen
rarely.
Even
in
dry
years,
aquifers
may
show
gains.

7. Other Integral Parts of the Lochquifer Alternative: Please refer to the sections listed
below, as they are integral parts of the Lochquifer Alternative. Generally, they are also
related to other projects or ideas as well, which is why they are not simply inserted here.
Sec. 4 Include the Neighbors
Sec. 8e 4 Time-spans of Loch Use
Sec. 8g Dealing With Turbidity
Sec. 9a Tide-Over Projects
Sec. 9c Diversion Systems
Sec. 9d Pond Buy/Sell/Lease
Sec. 10a to g Regulatory Buy-ins First
Sec. 11 Multipurpose Settling Pond
Sec. 12 Diversion Alternatives
Sec. 14 Upgrade Existing Intertie
Sec. 15 Cross-County (Raw)
Pipeline
Sec. 23 Loch-Down Alternatives
Sec. 24 Cowell RR Pipeline
Sec. 25 Guidance Questions
Illustrative Art
The image below was created in 2013 by professional illustrator Erika Aitken of Santa
Cruz. It compares the Lochquifer plan with recent past practice. The volume of each
water transfer is represented approximately by the width of each arrow. In essence,
abundant winter water not needed by fish goes from the river via Loch Lomond to the
users. Water treatment facilities and wells are omitted here for simplicity. In the
Lochquifer plan the aquifers are shown as having been filled by annual rainfall, because
wells generally are no longer used and so do not compete. An exception occurs in the
driest years, when wells dispense water from the aquifers’ vast store.

9. Cost estimates:
M$ Comment (Figures represent costs for minimum configuration plus
hydroelectric option)
35 Conventional 8 mgd water treatment plant, including land acquisition
10 De-turbidifying diversion devices, installed: 2 @ $5M each
3 Settling pond/infiltration gallery and other pre-treatment at Felton Diversion
14 Raw water pipeline, 5 miles @ $1.1M/mile, and pumpstations
5 Potable water pipeline, 4 miles @ $1.1M/mile (no pump necessary)
5 Hydroelectric facility (small pre-fab turbine/generator)
15 Design and permitting
87 TOTAL capital cost
26 Bond interest* (30-year fixed rate at 3.125% on all but the first $35M = $52M x
50%)
103 Sum of capital cost plus finance cost
1.29 Amortized over 80-year operating life: annualized capital+finance cost
1.00 Operation and maintenance, per annum (includes credit earned for
hydroelectricity)
2.29 Total per annum cost
$380 Cost per acre-foot in $, not M$, producing 6,000 AFY -includes bond
interest*
$348 -not including bond
interest*
*Note: competing projects may or may not include bond interest in their cost estimates.
Further study:
Which Lochquifer option is the best?
• Minimum Lochquifer alternative: put a Ranney collector or two at Felton to fix
the current pipeline gridlock, de-turbidify, and boost the amount diverted (Terry
McKinney proposal).
• Cowell Railroad Pipeline plus the above: boosts yield, saves energy, water-loops,
repurpo-ses Graham Hill Rd pipeline section to be a potable intertie with
Scotts Valley. (Section 24)
• Original Lochquifer proposal: put a Ranney collector(s) at Felton, add a booster
pump near Ben Lomond to increase the capacity of the pipeline, and add a
second pipeline to the Loch to divert enough water to rest all the wells of several
water districts and recharge aquifers ASAP.
• Original Lochquifer with buffer storage, e.g. add a pond, quarry and/or
infiltration gallery. Probably unnecessary if pipeline flow rates to Loch are high
enough, and especially if no pre-treatment is needed for Ranney water to enter
the Loch.
• Loch-Down, which diverts water at elevations above the Loch, where water
quality is higher, and to save energy, operate during power outages, provide
flood control, etc. (Section 23)
• Cross-County Pipeline (Raw water at 500-foot elevation) enables diversion into
the Loch of clean water from high-elevation streams from Bear Creek to Soquel
Creek, as well as augmenting any of those streams during dry times; may get
enthusiastic backing from fisheries regulators regarding water rights acquisition.
(Section 15)

10. • Hydroelectric option: just before treated water gets all the way down the
mountain to users, insert a pre-fab hydroelectric generator in-line with the
pipeline. (Section 23)
What does it take to use Ranney collectors in the site areas contemplated for new
diversions?
What are the details of the optimal pre-treatment to meet Loch standard?
What are the most important details regarding the new treatment plant; will it require
membranes?
How much sludge will the existing Felton Diversion & its new settling pond remove? (nil
for Ranneys)
What does it take to get regulators’ early buy-in, so as to obtain water rights in 3 to 4
years?
What tide-over projects would be best, while we wait for water rights?
What does it take to make a profit from the Felton settling pond/infiltration gallery?
Would it be worth it to put a Ranney collector in the Loch? Benefits:
• the new treatment plant might not have to remove particulates,
• which means it would not have to dispose of much sludge,
• all contributing to lower construction and operating costs.
if and when the Loch silts up, the Ranney collector might continue to make the Loch
useful as a reservoir.