Mark Twain supposedly said “Whiskey is for drinking; water is for fighting over.”
In the early 1860s Twain traveled to Virginia City and worked as a silver miner. Later, he became a journalist and moved to San Francisco. His travels throughout the west taught him the supreme importance of water.
Despite the above-normal precipitation over the last two rainy seasons, we continue to see competition for water between agricultural, environmental and residential interests; and as water rates increase for many communities, water conservation is becoming increasingly important.
One way to conserve water, protect the environment and reduce your water bill is by utilizing a landscape irrigation controller (also known as “sprinkler timer”) that has a Watering Index Number setting. A dial on the controller allows you to adjust the setting for your landscaping and garden water needs throughout the year for your particular location.
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The Watering Index Number is normally higher in July and August as a greater amount of evaporation takes place and rainfall is scarce, but decreases during the winter with less sun and more rain. In other words, the Watering Index Number changes to reflect your garden’s changing needs for water. As new Watering Index Numbers come out, you simply adjust the dial on your irrigation controller to match the Watering Index Number value.
The Watering Index is based on evapotranspiration (ET). This term describes the transport of water into the atmosphere from soil due to evaporation and transpiration by plants in terms of inches of water per day.
An amazing amount of water transpires from the leaves of plants. A single large oak tree in our county can move 100 gallons or more of water into the air in just one day during the summer. An acre of corn gives off about 3,000 to 4,000 gallons of water each day.
ET is calculated from weather stations that measure solar radiation, air temperature, soil and air humidity levels and winds.
California residents can obtain the current Watering Index Numbers for their area at www.waterdex.com. This site considers annual weather cycles and historical weather data.
However, current local index number settings for San Luis Obispo and surrounding communities can be found at Chris Arndt’s website at SLOWeather.com. Chris told me he recalculates the Watering Index Numbers daily, but you should only need to adjust your controller once every week or two, depending on the weather and how fast the index changes.
He also said the index is only a guide, and you must pay attention to the health of your plants and the operation of your irrigation system. You should also water in the early morning when the air is still and cool. Avoid watering between the hours of 10 a.m. and 5 p.m. when much of your water will be lost to evaporation.
A thermal low will persist over the central valley while the Eastern Pacific High will remain stationary about 2,000 miles west of California and strengthen to 1,038 millibars over the next 96 hours. At the same time, an upper-level low pressure system over the Pacific Northwest will also strengthen.
This condition will produce extensive night and morning low marine cloud cover, drizzle and fog along the coast and coastal valleys. Strong to gale force (25- to 38-mph) northwesterly (onshore) winds along the coastline will move the marine layer inland and will produce cooler temperatures throughout San Luis Obispo County.
High temperatures in the North County will range between the high 80s to low 90s while the temperatures will be closer to 100s in the southern San Joaquin Valley.
The coastal valleys (San Luis Obispo) will range between the low to mid-70s.
The northwesterly facing beaches (Montaña de Oro, Los Osos and Morro Bay) will range between the high 50s to low 60s, while the southwesterly facing beaches (Cayucos and Avila Beach) will range between the high 60s to the low 70s.
Temperatures by mid-week may be as much as 10 degrees below normal for this time of year. This cool pattern is forecast to persist until next weekend and possibly into the week of July 18 for the first few days of the Mid-State Fair. Note: The average maximum temperature for San Luis Obispo for July is about 78 degrees and about 94 degrees in Paso Robles.
Today’s surf report
Today’s 5- to 7-foot northwesterly (320-degree deep-water) sea and swell (with a 5- to 10-second period) will remain at this height and period through tonight.
This northwesterly (320-degree deep-water) sea and swell will decrease to 4 to 6 feet (with a 5- to 8-second period) on Monday, further lowering to 3 to 5 feet with same period Tuesday. This northwesterly (320-degree deep-water) sea and swell will remain at this 3- to 5-foot level (with a 5- to 8-second period) through next Saturday.
From the south:
A series of large storms in the Southern Hemisphere will generate 1- to 2-foot Southern Hemisphere (210-degree deep-water) swell (with a 15- to 18-second period) Today.
Another Southern Hemisphere (200-degree deep-water) swell train will overlap today’s swell and will produced a combined 1- to 3-foot southern swell (with a 15- to 22-second period) tonight, increasing to 2 to 3 feet (with a 16- to 20-second period) Monday into Tuesday. This swell will gradually decrease Wednesday through Friday.
Seawater temperatures will range between 55- to 57-degrees through today, decreasing to 52- to 54-degrees on Monday and remaining at this level through Friday.
For those planning outings near mountain streams, rivers and reservoirs, please be extra vigilant and take appropriate safety measures.
This year’s deep snowfall and cool spring has left California’s overall snowpack at more than three times its usual water content as of June 1, meaning snowmelt will be more rapid than usual when temperatures rise. This snowmelt will result in swift and cold river flows that can create treacherous conditions.
Know the water
Sudden immersion in cold water can stimulate the “gasp reflex” causing an involuntary inhalation of air or water. It can even trigger cardiac arrest, temporary paralysis, hypothermia and drowning. When faced with swift water, even the strongest swimmers may be easily overwhelmed.
Cold water entering the ear canal can cause vertigo and disorientation. This may confuse swimmers, causing them to venture deeper into the water.
Know your limits.
Swimming in open water is more difficult than in a swimming pool — people tire more quickly and can get into trouble.
Cold water causes impairment leading to fatalities. It reduces body heat 25-30 times faster than air does at the same temperature.
Many unseen obstacles can be lurking below the water’s surface. Swift water can make these obstacles even more treacherous.
Wear a life jacket
Conditions change quickly in open water and even the best swimmers can misjudge the water and their skills when boating or swimming. Wearing a life jacket can increase survival time.
A life jacket can provide some thermal protection against the onset of hypothermia and keep you afloat until someone can rescue you.
Actively supervise children# in and around open bodies of water, giving them your undivided attention. Appoint a designated “water watcher,” taking turns with other adults.
Teach children that swimming in open water is not the same as swimming in a pool: they need to be aware of uneven surfaces, river currents, ocean undertow and changing weather.
John Lindsey, media relations representative for PG&E and a local weather expert, has lived along the Central Coast for more than 24 years. To subscribe to his daily weather forecast or ask him a question, email him at pgeweather@ pge.com.