[Vision2020] Sprinklers vs. Drip line: was Walmart Gets Nod for Starting Work

[Garrett Clevenger]

Matt probably knows a whole lot more about sprinklers than I, since his company is Raindrop Sprinklers.

For our needs, though, compared to the system we have set up, sprinklers wouldn't be as efficient. And compared to large farms that are irrigated with sprinkler systems, we are way more efficient.

The prob em with sprinklers is that there is a lot more evaporation that happens compared to drip lines. The flow rate may be less in sprinklers, but a less percentage of the water emitted makes it to the plant roots that we want to grow than drip line.

For one thing, since sprinklers cause the water to have more surface area and the water is sprayed in the air, there is more chance for evaporation from the sun and wind. Drip lines slowly emit the water right on the soil and right where we want it, so evaporation is minimized. It also means less mud in the walkways.

I also like to cover up the drip line, with either soil or mulch, which reduces evaporation.

Sprinklers broadcast on areas that we wouldn't want to get water, like between our beds, which means more water is being used to water weeds, which we then have to work to hoe or pull.

We also have to be concerned about getting the plants wet to prevent sun scorching and disease, so if we were to use sprinklers, we'd have to make sure we do in the early morning so the water would evaporate (more lost water) before the sun is out in full force.

For large farms, they mostly use old sprinkler systems. They are leaky and usually running during the heat of the day in order to water the large areas. I can't remember the exact percentage of lost water due to using sprinklers on these farms, but a good portion of that water is never used by the plants.

So for us, it seems sprinklers would be more inefficient (and cause more problems) compared to using drip lines and our drip lines are way more efficient compared to large farms using sprinklers.

gclev


--- On Fri, 3/13/09, Matt Decker <mattd2107 at hotmail.com> wrote:

> From: Matt Decker <mattd2107 at hotmail.com>
> Subject: RE: [Vision2020] Walmart Gets Nod for Starting Work
> To: garrettmc at verizon.net, vision2020 at moscow.com, jampot at roadrunner.com
> Date: Friday, March 13, 2009, 9:05 AM
> Garrett,
> "So unlike many larger scale farms, our water use is
> probably way more
> efficient, as we use drip line instead of sprinklers, which
> are very
> inefficient".
> 
> Drip systems are the best way to spot irrigate. I always
> recommend drip irrigation to my customers if they are trying
> to water their shrubs. Garden areas can be tricky though. I
> still recommend drip but also have no problems if sprinkler
> heads want to be used. Granted a bunch of scenarios come
> into each property. IE wind, whats being watered,etc.
> 
> Here is my reasoning; lets say you are watering a 30'
> by 100' parcel of lettuce. A T-tape(netafim) drip line
> which has a 12" drip spacer puts out about .6
> gph(gallons per hour per dripper) but you have rows spaced
> at intervals of 2 feet. Meaning you have 15 rows. If you
> water at lets say 30 minutes per cycle you could be putting
> out 450 gallons. I do prefer this method because you are
> putting the water right where you want it, on top of the
> roots.
> 
> I could design sprinkler head irrigation to cover the same
> portion which could water the veggies while potentially
> saving water.
> Sprinkler heads are designed to cover broad areas, so if
> the shrub or veggies have the same desired water needs, then
> there is no reason why you couldn't use heads. 
> 
> Using sprinkler heads(12 heads needed), each that put out
> about .6 GPM for a period of 30 miuntes would put out about
> 216 Gallons. Problem with this is that you are watering
> between rows and some veggies may not like overhead
> watering. However, in order to rototill, you would not need
> to remove the drip lines each time.
> 
> The sprinkler industry has gone to great measures to make
> irrigation environmentally friendly. New timers, sensors and
> heads have made it so a person can save 30% water compared
> to "old school" hose and sprinkler method.
> New heads now come with pressure compinsating features,
> reducing evaporation. Some have nozzles that make the
> droplets bigger, thus insuring the water reaches desired
> target.
> 
> To say that sprinkler heads are "very
> inefficient" is not true and a thing of the past.
> Perhaps in your application, heads might be the improper
> method, if you are trying to selectively water. If however,
> your design of the plots includes same watering needs, then
> overhead watering could be benifitial.
> 
> I'm not trying to say your doing something wrong but
> just trying to show that sprinkler heads are not
> inefficient. 
> 
> Take care,
> 
> MD