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.

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.

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.)

 

 

     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  

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      

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.        

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.

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)

• 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.