beginning flood irrigation

[greenbean]

What are the basics of flood irrigation? I bought an old farm with 25 acres that used to flood irrigate. cotton and alfalfa I think. Its all leveled out, with a slight slope for drainage. It has a good well, a huge good pump. This pump has a pipe going to an earth holding tank. The tank has a big wheel which opens a plate to let the water out of the tank to a concrete ditch which is about 500 feet long, leading down to the edge of the field.. obviously the water is diverted down this ditch to the crop.

So far so good. But scattered all over the field are these big metal and PVC pipes about 3 inches wide and 20 feet long.. I dont know what these are for. Can someone give a greenhorn some help? I'd like to start an alfalfa crop. Flood now, hopefully drip when & if I can afford it...thanks

[Irrigator]

I have a bit of experience with flood irrigation and my guess is the pipe are for one of two reasons:

1. They are in areas where the ditch was crumbling or weak so pipe was used to ensure the water did not leak out of the ditch where it was not supposed to.

2. Perhaps they were using the pipes as gates. Perhaps there are ways of pluggin the pipes to allow more water to go to a certain are and the pipes are part of a system to divert the wate.

Do either of these make sense? It would be really great if you could give us a picture.

[greenbean]

Irrigator, here is the only pix i have. There are hinge-like devices on one end of each pipe. hard to see, but there are several lying in the concrete ditch upper right corner.

[Irrigator]

To me it looks like a way to move water around where there are no ditches. Correct me if I am wrong but the pipe in this picture seems to be feeding the ditch. there will always be areas where you do not need to flood irrigate but you need to move water through. It looks like this is what it is for.

[Irrigator]

This is from Wikipedia (http://en.wikipedia.org/wiki/Irrigation), pay special attention to the part about siphon tubes.

Ditch (furrow) irrigation

Ditches (http://en.wikipedia.org/wiki/Ditch) can be dug with hand tools, turned with a plow pulled by an animal or tractor (http://en.wikipedia.org/wiki/Tractor), or precisely fashioned using laser (http://en.wikipedia.org/wiki/Laser)-guided instruments depending on economic and physical factors such as the size of the field, the types of technology available, and the cost of manpower. Plants (http://en.wikipedia.org/wiki/Plant) are grown in raised beds or listed rows. Water is distributed throughout the field via canals (http://en.wikipedia.org/wiki/Canal), unlined ditches, or furrows, between the rows or beds by use of rigid gated plastic (http://en.wikipedia.org/wiki/Plastic) or aluminum (http://en.wikipedia.org/wiki/Aluminum) pipe (http://en.wikipedia.org/wiki/Pipe), layflat plastic with holes punched at each furrow, concrete (http://en.wikipedia.org/wiki/Concrete) or plastic lined ditches, or unlined ditches. Where ditches are used, siphon tubes (http://en.wikipedia.org/w/index.php?title=Siphon_tubes&action=edit) move water from the main ditch to the furrow. When pipes are used, water flow can be controlled by turning it on or off at the local source or by using automatic or manually controlled gates to transfer it from one set of ditches to another. Unless the field is small or very level, parts of it may suffer from water-logging while other parts may be too dry. Depending on heat (http://en.wikipedia.org/wiki/Heat), wind (http://en.wikipedia.org/wiki/Wind), and soil (http://en.wikipedia.org/wiki/Soil) permeability (http://en.wikipedia.org/wiki/Permeability_%28geology%29), much water may be lost before it can benefit the plants. Automatic valves, also known as surge valves (http://en.wikipedia.org/w/index.php?title=Surge_valves&action=edit), can increase the efficiency of furrow irrigation because they alternately wet the furrows and allow the soil infiltration rate to slow prior to using the furrow for actual irrigation.

Once common in the United States (http://en.wikipedia.org/wiki/United_States), many ditch irrigation systems have been replaced because of high labor costs and increasing demands on water resources (http://en.wikipedia.org/wiki/Water_resources). Furrow irrigation also has a tendency to raise the water table in some areas and cause soil salination (http://en.wikipedia.org/wiki/Soil_salination), requiring drainage (http://en.wikipedia.org/wiki/Drainage). These types of systems are still common in other parts of the world.