Irrigation Desain : sprinklers (1)

2 Feb

A sprinkler requires two things to operate- water flow and water pressure. When a sprinkler system design fails, it is almost always due to a lack of water pressure at the sprinklers. This is important because, if you are like 99% of the people using this tutorial, you are thinking solely in terms of water flow. "How much water do I need (or have available) for my sprinkler system?" That’s an important question to ask, but it must go hand in hand with its sister question, "How much pressure will I have at the sprinkler?" The "at the sprinkler" part of that question is critical! Allow me to demonstrate by means of a simple, if not somewhat stupid, example:

Go get a sprinkler, any sprinkler will do fine, even one you put on the end of a hose. Now get a big bucket of water. 5 gallons is an ideal size. Now place the sprinkler on the ground (somewhere outside is strongly recommended) and pour the water into the sprinkler inlet. Did the sprinkler operate correctly? Did it water a good size area? NO? Why not? It had plenty of water. Ahh… but it didn’t have any water pressure! The water you poured into it didn’t have enough pressure to make the sprinkler operate.

Water pressure is the ENERGY that makes the sprinkler do its thing. Water pressure is like the gasoline for the car. Flow is like the distance the car travels. No gas, no travel. No water pressure, no water flow. (Yes, Ms. Ph.D. in hydraulics, that’s not a perfect analogy- but it works for most people.)

We understand that water requires pressure to push it through the pipes. It also stands to reason that just as a car uses up gas when it travels, the water also uses up the pressure as it flows! So from the moment the water starts flowing through the pipes of your water system, it is using up the pressure. We refer to that as "losing pressure" when designing. Some pressure is lost when the water goes through a water meter. It loses some more pressure as it moves through the various pipes in your yard and house. Squeezing through valves and/or a backflow preventer eats up more pressure. Everything the water encounters as it moves from the water source to the sprinkler uses up a small amount of the water pressure.

So here is the key to a good sprinkler system design: After the water gets through all those pipes and valves and reaches the sprinkler head, there still must be enough pressure left to make the sprinkler head operate correctly. If there isn’t, it’s just like the sprinkler you poured water onto in the example above. All the water in the world won’t make it work without pressure! By using the correct sizes of pipes, valves, etc. you can control how much pressure is lost in the irrigation system, and that, my friends, is what sprinkler system design is all about!

So here’s sprinkler design in a nutshell: Sprinkler design is simply manipulating how much water pressure is lost between the point the water enters your yard and the sprinkler head. That’s right, you are about to learn how to manipulate! (Come on, you’ve always had a secret desire to be able to manipulate, right?)

The Sprinkler System Design Process:

Step #1:
You’ll learn how to accurately measure your yard and then sketch out the area to be irrigated. Next some information needs to be obtained. Don’t worry, I’ll tell you how and where to get it. We’ll also make an "educated guess" at an Initial Flow Rate, which will serve as a starting point for the flow and pressure manipulations mentioned earlier.

Step #2:
We’ll take a look at those things that will "eat up" your water pressure as the water moves to the sprinklers. I’ll show you how to find out how much pressure each one of those items will use. While we’re at it, you’ll learn about sprinkler heads, valves, backflow preventers and all the other equipment that will go into your new sprinkler system. You’ll learn how to tell a good product from a bad one, regardless of brand names. Then we will manipulate those pressure losses and end up with the actual flow and pressure values you will use for your sprinkler system. Don’t panic, there’s a lot of information to cover, but I will lead you through it item by item. It will be easy if you take it one thing at a time and don’t freak out on me!

Step #3:
Here’s where we actually start drawing the sprinkler system on paper. Finally! You will learn a lot more about sprinklers in step #3. It’s a long wait, but if you had started trying to figure out where to put the sprinklers back in step 1 or 2, like some tutorials do, you’d be erasing them now!

Step #4:
Here’s where you’ll divide your sprinkler system up into zones and lay out the piping routes. This is where we’re going to make the right decisions to create a sprinkler system that uses less water than most and gives you healthier plants. Bad sprinkler design is a major cause of turf disease and wasted water.

Step #5:
Finally, we will determine the size of each pipe and clean up a few small details. We’ll look at how to automate the sprinkler system if you want to.

Low-energy spray irrigation

2 Feb

It is called a Low Energy Precision Application (LEPA) center-pivot system. Instead of high-power spray units, this system has small water sprayers hanging down from a large water-carrying pipe above. At the bottom of each pipe, very close to the ground, is a nozzle that gently sprays water onto the crops.

Because the nozzle is so close to the ground, you lose a lot less water to evaporation than you would with a traditional spray-irrigation system. Plus, electricity is saved because it takes less to use these low-powered systems. These systems allow more than 90-percent of the water pumped to be used by the crop — pretty efficient!

Drip Irrigation

2 Feb

The bushes in this picture are being irrigated using the drip irrigation method, which is the most common type of "microirrigation." If you look closely you’ll see the small horizontal pipes that are slowly dripping water running just above the ground. Drip irrigation is one of the more advanced techniques being used today because, for certain crops, it is much more efficient than traditional spray irrigation, where a larger portion of the water is lost to evaporation.

In drip irrigation, water is run through pipes (with holes in them) either buried or lying slightly above the ground next to the crops. Water slowly drips onto the crop roots and stems. Unlike spray irrigation, very little is lost to evaporation and the water can be directed only to the plants that need it, cutting back on water waste.

Advantages of microirrigation

Microirrigation has gained attention during recent years because of its potential to increase yields and decrease water, fertilizer, and labor requirements if managed properly. Microirrigation systems can apply water and fertilizer directly to individual plants or trees, reducing the wetted area by wetting only a fraction of the soil surface; thus, water is applied directly to the root zone.

  • Microirrigation is a low pressure, low volume irrigation system suitable for high-return value Crops such as fruit and vegetable Crops.
  • If managed properly, microirrigation can increase yields and decrease water, fertilizer and labor requirements.
  • Microirrigation applies the water only to the plant’s root zone and saves water because of the high application efficiency and high water distribution uniformity.
  • Microirrigation can irrigate sloping or irregularly-shaped land areas that cannot be flood irrigated.
  • Any water-soluble fertilizer may be injected through a microirrigation system.

Aqueducts

2 Feb

f you live in an area where ample rain falls all year, you won’t see many aqueducts like the ones pictured here. But there are many areas of the world, such as the western United States, where much less rainfall occurs and it may only occur during certain times of the year. Large cities and communities in the dry areas need lots of water, and nature doesn’t always supply it to them.

Some parts of the western U.S. do have ample water supplies, though. So, some states have developed ways of moving water from the place of ample supply to the thirsty areas. Engineers have built aqueducts, or canals, to move water, sometimes many hundreds of miles. Actually, aqueducts aren’t a high-tech modern invention—the ancient Romans had aqueducts to bring water from the mountains above Rome, Italy to the city.

Can you see something about the aqueduct in these pictures that causes some water to be lost in transit? In places where the climate is hot and dry, a certain portion of the water flowing in the aqueduct is bound to evaporate. It would be more efficient to cover the aqueduct to stop loss by evaporation, but the cost of covering it must be weighed against the value of the evaporated water.


Solar Pump for Irrigation Water Pumping Station

6 Jul

Setelah bahan bakar diesel naik akibat hilangnya subsidi, banyak petani di Pulau Jawa (khususnya Jawa Tengah dan Jawa Timur) menggunakan minyak tanah oplosan (dicampur dengan teer/oli bekas) sebagai bahan bakar pompa untuk penyediaan air irigasi. Dari perkembangan yang ada dan arah kebijakan pemerintah yang semakin membuat langka minyak tanah, akan menyebabkan harga minyak tanah terus naik. Jika hal ini terjadi maka ribuan petani yang menggunakan minyak tanah oplosan sebagai bahan bakar pompa irigasi akan menjumpai angka ketidak layakan biaya operasional. Dari beberapa sumber yang diperoleh langsung dari petani dalam kelompok pengguna pompa irigasi tersebut, penggunaan bahan bakar diesel (minyak solar) terlalu mahal (dalam hal ini bisa diterjemahkan petani akan mengeluarkan cost terlalu mahal untuk operasional dan tidak layak secara ekonomi apabila dibandingkan dengan hasil panen), maka mereka banyak memaksakan penggunanaan minyak tanah oplosan tersebut.

Tahun 2010 diperkiraan akal-akalan versi petani kampung Jawa tersebut akan mustahil lagi dilaksanakan. Gebrakan pemerintah menggalakkan pengembangan bio-diesel sampai saat ini belum sampai ke daerah pedesaan (ke ibukota kabupaten saja belum tentu ada).

Sumber : mohab.org

Pindah rumah – pindah domain

17 Apr

Sabtu 18 April 2009 saya sekeluarga menempati rumah baru (walaupun baru setengah jadi, karena dari rencana lantai 2 baru selesai lantai 1).

Biar lebih flexibel juga blog saya pindah alamat ke mohab.org

Semoga rumah baru dan domain baru memberi suasana serta rezeki baru seperti harapan

PLTA : Arsip 2 (gambar)

14 Apr
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