The Process
Pasture pipeline is shallow buried (12-14”) to protect it from damage. It cannot be used for year round water because it is above the frost line. It should be emptied at the end of each season, but can be left full of water as long as it is not frozen under pressure.
Pasture pipeline season in Alberta can reasonably extend from May 1 (surface ground is thawed) until October 15. If you are watering large cattle herds and can protect the ends of your pasture pipeline from freezing, you can go later than the middle of October, but doing so adds the risk of freezing the line while under pressure.
Installation
Installing pasture pipeline requires a specialized plow and a 100 horsepower tractor with two hydraulic outlets. You can use a smaller tractor if you plow your pipe to a shallower depth.
Joints are best done with some form of fusion technology (melts the pipe or joints together) as high or medium density pipe is not conducive for standard water line fittings. The only places you need to fuse pipe is on the ends (install a pipe to thread fitting) and where you want to install spur tanks (install a T and a pipe to thread fitting).
Pasture pipelines can vary from less than a ¼ mile to several miles in length.
There is an important relationship between length of the pipeline between source and end and the number of head being watered. Larger herds and longer distances require bigger diameter pasture pipeline. Generally, 500 cow herds will require 2” pipe, while 200 or less can be serviced adequately with 1.5” pipe. Pumping distances longer than 3 miles may require increased storage capacity on both ends of the pasture pipeline.
Topography is also an important consideration. You will gain or lose pressure with gains or losses of elevation between source and outlet. Pumping up hills will probably require the addition of higher pressure pumps (and possibly higher pressure pipe) while pumping down hills may require pressure reduction. If you are extremely fortunate you may be able to use gravity to deliver your water through a pasture pipeline.
