Water Management: Irrigation and Drainage
Part of farming is having water when you need it and not to have too much when you don't need it. We learned that even the best intentions can sometimes give a bad result.
Years ago we had help from a couple of Oregon State graduate students who were studying the effects of ground covers on the growth of trees. They put moisture blocks at the depths of 1', 2' and 3'. We all shared the work of taking readings for those blocks. It was a huge amount of data that told us the ground covers were taking water away from our baby trees.
We decided to irrigate our new plantings and built a pond. The pond is a great place for blue herons, osprey, red-winged blackbirds and the occasional beaver. It also is an emergency supply of water in case of fire. When we built it, there wasn't a fire department out here.
We irrigate once a year for approximately 1-2" of "rain". Once the trees are 3 or 4' tall their root system is established and they don't need to be irrigated.
We learned early on that we needed to manage the water that is already here, too. One time we flew over the farm in a small plane. We discovered that it wasn't just the water on our farm that was important, but also the water and farming practices across fence lines both upstream and downstream that were important, too.
The first thing the three rolls of pictures showed, was the high water table in some fields that was damaging or killing trees. We have now tiled most of our farm. As expensive as that was, it has paid off in better root development and far better quality trees and fewer trees dying or stressed due to a high water table in the winter.
The next thing we did was to put in diversion ditches and piping to control the water coming into our farm from the neighbors. Where necessary, the ditches have rock structures to slow the water down and to allow the erosion coming from our neighbors to settle here. Fortunately, our neighbors downstream have managed their water so that it does not back up into our farm.
The tall fescue that was a problem out in our tree fields is actually a help in our grass waterways and non-rocked wagon roads. It is tough, tough, tough.
Our stream bank enhancement program took a great jump in 2007. We have fattened out the trees and brush along all our waterways. What once was pasture is now planted to ponderosa pine, Douglas-fir, western red cedar, grand fir and many deciduous shrubs.