2022-04-26 Callimanis Presentation 3 Rob Hedges LQRRD to PC PHFrom: Alena Callimanis <acallimanis@gmail.com>
Sent: Tuesday, April 26, 2022 1:43 PM
To: Tania Flores; Cheri Flores
Cc: Rob Hedges
Subject: Presentation number 3 - Rob Hedges LQRRD Planning Commission April 26
Attachments: Rob Hedges Planning Commision Presentation.pdf
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Here is the presentation for Rob Hedges for LQRRD presentation number 3.
Alena Callimanis
The Water Issues
Water Volume & Loss to Evaporation
Water Cooling and Energy Requirements
Rob Hedges
BioChemist
La Quinta
The proposed surf pool will cover more than 12 acres and have an
additional intermittently -wet concrete area of almost 4 acres. Evaporation
will occur from up to 16 acres of wet surface.
Evaporation rate is usually measured as the decline in surface level per
month. Factors affecting the volume of pool evaporation include surface area
of the pool, water temperature, water movement/agitation, air temperature, air
humidity and air movement.
A 2012 U.S. Army Corps of Engineers study of evaporation rates in five
Texas reservoirs shows that monthly losses due to evaporation vary from
3"/month in the winter (Dec, Jan) to 13"/month in the hot months. See the
next slide. Texas has much colder winters than La Quinta and higher
humidity both of which mean that the La Quinta rate will be higher.
Figure 2 on page 12 of
the US Army Corps of
Engineers study.
12 Estimation of Evaporation from Open Water
Average monthly pan evaporation in inches
14.00
13.EE
120E
11.00
1D.DD
9.00
B.00
7.00
6.00
5.00
4.0E
3.00
2.00
1.00
D.00
EXPLANATION
Benbrook Lake
Canyon Lake
Granger Lake
Hords Creek Lake
Sam Rayburn Lake
January February March April
May
June July
Month
August September October Navarnber December
Figure 2. Average monthly historical Class A pan evaporation from five reservoirs in Texas, 1953-2010.
Projected Surf Park Evaporation at Coral Mountain
From the Texas data, an extrapolation can be made for the proposed
surf pool. At the high end, the decline in surface level multiplied by the
evaporation surface area gives a daily evaporation volume of a quarter
million US gallons in the proposed pool.
Given that La Quinta temperatures are higher, particularly in the winter
months, the humidity is far lower and the surface of the pool will be
agitated for many hours each day, it's reasonable to expect that the
actual evaporation loss will substantially exceed 250,000 US gallons per
day. And this must be replaced with potable water.
A Comparison to the WADI Adventures Surf Basin in
UAE
WADI is a 3-acre 2,800,000 USG surf pool in the UAE. Evaporation
replacement averages 40,000 USG per day for May to November and
10,000 USG per day from December to April. WADI maintains a pool
temperature of 84F.
Simply applying the WADI evaporation rate experience (five times larger
evaporation surface) projects a loss of 200,000 USG/day for the new pool.
This confirms that the previous evaporation projection is reasonable.
Cooling Issues
As anyone with a pool in La Quinta knows, in summer, the pool turns into a
hot tub. Surfing is an energetic activity and to be safe from heat stroke,
water temperature should be lowered to about 84F. Given that water holds
more heat per unit mass than any other substance, cooling 18,000,000 USG,
and keeping it cool, requires a massive amount of energy.
Cooling that volume of water from 100F down to 84F will require the same
amount of energy in 1,000,000 KWH of electricity. It also requires heat -
exchange equipment similar to the exterior condenser and fan on a home AC
unit but much, much larger! The heat energy in the water has to be
dispersed into the air just like a home air conditioner.
During winter months, no cooling will be required. Just as in oceans,
surfers will wear wet suits as necessary. But in the summer, with local
night-time temperatures above 80F, a large pool will not lose enough heat
to maintain a safe temperature in the low 80s.
The cooling apparatus required for an 18,000,000 USG pool will be
massive. It will require numerous huge, noisy fans and large pumps.
If the electricity to power the cooling apparatus comes from IID, significant
equipment will have to be installed or upgraded to deliver this much
electricity. And this delivery will be at the same time as peak electric
demand for cooling homes and business throughout the valley.
There are lots of questions I can't answer:
1. How will the noise be abated?
2. Will the increased electric demand affect local rates?
3. Will large diesel generators be installed to reduce the extra draw from
the grid?
4. How will the noise from cooling and diesel equipment affect the quality of
life in the proposed residential community and nearby communities?
5. How will the generation and cooling equipment affect the visitor
experience and the spectator experience at surfing events?