Colorado Water 2012: Agricultural water use

irrigation.jpg

Here’s the latest installment of the Valley Courier’s Water 2012 series. Nathan Coombs, manager of the Conejos Water Conservancy District, has written a primer about water and agriculture. Here’s and excerpt:

1) Priority- like it implies, there are certain users of water that get priority over others. This priority system is based on “first come, first served.” The earlier in history that someone put water to a good (beneficial) use, the lower their priority number. This number however, is like the placing in a tournament- #1 is best or senior and so on. A water right can however be both senior and junior. For example the #2 priority is senior to the #3, yet junior to #1. The actual physical location along the river is basically irrelevant. The priority number determines who gets the water in what order.

2) Decree- this term is used to define how much water, and to what purposes the water is used. For example, you cannot use water for raising fish unless this purpose is expressly granted in your decree. You also cannot take from the source (well or river) all that you want. Your decree states how much water to which you are entitled. The term decree is applicable to both river (surface) water and well (ground) water.

3) Compact- this is a legal term for a federally recognized interstate or international agreement. The Rio Grande River Compact dictates how water from the Rio Grande River is divided between Colorado, New Mexico, Texas, and Mexico. It was developed to be as equal and fair as possible. (This topic is always up for coffee shop discussion!)

4) Unconfined aquifer- this is the area of water that exists from immediately below the surface of the ground to a depth that varies from about 75 to 200 ft. At the bottom of this “layer” is a boundary of clays and Malpais lava flows that really slows water from moving up or down.

5) Confined aquifer- this is the area that is below the unconfined. Where the unconfined is relatively shallow, the confined can be thousands of feet deep. This is where artesian water comes from because of usual upward pressure.

6) Diversion- Diversion describes the location and method used to get water from a river or the ground. A headgate on the river is a diversion for surface water and a well is the diversion for the ground water.

More Colorado Water 2012 coverage here.

Leave a Reply